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Objective: The primary goal of this study is to determine trends in patient 30-day postoperative readmission and reoperation following elective posterior lumbar fusion (PLF) between 2006-2016., Methods: We retrospectively identified patients in the ACS-NSQIP database who underwent elective, non-emergent PLF from 2006 to 2016. Descriptive statistical and time trend analyses were performed on demographic, comorbidities, perioperative, and outcome variables. Primary outcomes were reoperation and readmission within 30 days and secondary outcomes were medical and surgical complications reported within 30 days of the operation. Linear and binary logistic regression were performed to adjust for patient specific confounders., Results: A total of 26,265 patients underwent elective PLF over the study period. Overall case volume increased from 0.02 % (n = 27) of all total cases in ACS-NSQIP in 2006 to 0.82 % (n = 8228) in 2016. Mean age increased from 51.22 [SE: 2.77] in 2006 to 60.57 [SE: 0.14] in 2016 (p < 0.001). For comorbidities, there was a decrease in smokers and increase in hypertension requiring medication and ASA Class 3. A readmission rate of around 5% per year did not vary significantly over the study period (p = 0.531). Unplanned reoperations declined from 7.4 % in 2006 to 3.1 % in 2016, but the overall trend from 2006 to 2016 was not statistically significant (p = 0.139). Reoperation demonstrated a significant association between age and BMI, but did not vary with admission year. Surgical site infections followed by hematomas and seromas were listed as the most common cause of both readmission and reoperation in PLF patients., Conclusion: Since the establishment of the ACS-NSQIP database, reoperation rates due to complications declined after 2006 and remained relatively stable. Readmissions were added as a variable in 2011 and had no significant changes over time., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Dermatomal maps are a mainstay of clinical practice and provide information on the spatial distribution of the cutaneous innervation of spinal nerves. Dermatomal deficits can help isolate the level of spinal nerve root involvement in spinal conditions and guide clinicians in diagnosis and treatment. Dermatomal maps, however, have limitations, and the spatial distribution of spinal cord sensory activity in humans remains to be quantitatively assessed. Here we used spinal cord functional MRI to map and quantitatively compare the spatial distribution of sensory spinal cord activity during tactile stimulation of the left and right lateral shoulders (i.e. C5 dermatome) and dorsal third digits of the hands (i.e., C7 dermatome) in healthy humans (n ​= ​24, age ​= ​36.8 ​± ​11.8 years). Based on the central sites for processing of innocuous tactile sensory information, we hypothesized that the activity would be localized more to the ipsilateral dorsal spinal cord with the lateral shoulder stimulation activity being localized more superiorly than the dorsal third digit. The findings demonstrate lateralization of the activity with the left- and right-sided stimuli having more activation in the ipsilateral hemicord. Contradictory to our hypotheses, the activity for both stimulation sites was spread across the dorsal and ventral hemicords and did not demonstrate a clear superior-inferior localization. Instead, the activity for both stimuli had a broader than expected distribution, extending across the C5, C6, and C7 spinal cord segments. We highlight the complexity of the human spinal cord neuroanatomy and several sources of variability that may explain the observed patterns of activity. While the findings were not completely consistent with our a priori hypotheses, this study provides a foundation for continued work and is an important step towards developing normative quantitative spinal cord measures of sensory function, which may become useful objective MRI-based biomarkers of neurological injury and improve the management of spinal disorders., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The coronavirus disease 2019 (COVID-19) pandemic has had a tremendous impact on the healthcare system. Owing to restrictions in elective surgery and social distancing guidelines, the training curriculum for neurosurgical trainees has been rapidly evolving. This evolution could have significant long-term effects on the training of neurosurgery residents. The objective of the present study was to assess the effects of COVID-19 on neurosurgical training programs and residents., Methods: A survey consisting of 31 questions assessing changes to resident clinical and educational workload and their sentiment regarding how these changes might affect their careers was distributed electronically to neurosurgery residents in the United States and Canada., Results: The survey respondents were from 29 states and Canada and were relatively evenly spread across all levels of residency. Nearly 82% reported that the inpatient and outpatient volumes had been either greatly (44.0%) or moderately (37.8%) reduced. Greater than 91% reported that their work responsibilities or access to the hospital had been reduced, with a significant reduction in work hours and a significant increase in resident didactics (P < 0.001). Senior residents expressed concern about their educational experience and their future career prospects as a result of the pandemic., Conclusion: Universally, residents have experienced reduced work hours and a reduction in their operative case volumes. Programs have adapted by increasing didactic time and using electronic platforms. It is quite possible that this remarkable period will prompt a critical reappraisal of the pre-COVID-19 adequacy of educational content in our training programs and that the enhanced educational efforts driven by this pandemic could be lasting., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Anterior cervical discectomy and fusion (ACDF) is the most common procedure for the treatment of degenerative cervical conditions. The objective of this study is to determine time-dependent trends in patient outcomes following ACDF for degenerative disease from 2006 to 2016., Methods: We used the National Surgical Quality Improvement Program (NSQIP) database to retrospectively review all patients who underwent elective ACDF between 2006 and 2016. A descriptive statistical analysis followed by time trend analysis was performed on demographics, comorbidities, perioperative, and outcome variables. Primary outcomes were reoperation and readmission rates. Secondary outcomes were medical and surgical complications reported within 30 days of operation., Results: A total of 36,854 patients underwent elective ACDF from the 2006 to 2016 NSQIP database. Mean age increased from 48.19 years [standard error: 1.49] in 2006 to 54.08 years [standard error: 0.12] in 2016 (P < 0.001). There was a significantly greater number of outpatient procedures from 2012 to 2016 (P < 0.001). The proportion of patients with American Society of Anesthesiologists classes 3/4 significantly increased over time (P < 0.001, P < 0.001, P = 0.005, respectively). Readmission risk, first documented in NSQIP in 2011, increased over time from 2011 to 2016 (P < 0.001). Unplanned reoperations have remained consistent at about 1.4%. Postoperative complications varied over time with no discernable patterns or trends., Conclusions: Since the establishment of the NSQIP database, there have been no considerable improvements in reoperation or postoperative complication rates based on available data, however, there have been increased rates of readmission. Changes in data collection and an aging patient population with greater burden of comorbidities could confound these trends., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: Machine Learning and Artificial Intelligence (AI) are rapidly growing in capability and increasingly applied to model outcomes and complications within medicine. In spinal surgery, post-operative surgical site infections (SSIs) are a rare, yet morbid complication. This paper applied AI to predict SSIs after posterior spinal fusions., Patients and Methods: 4046 posterior spinal fusions were identified at a single academic center. A Deep Neural Network DNN classification model was trained using 35 unique input variables The model was trained and tested using cross-validation, in which the data were randomly partitioned into training n = 3034 and testing n = 1012 datasets. Stepwise multivariate regression was further used to identify actual model weights based on predictions from our trained model., Results: The overall rate of infection was 1.5 %. The mean area under the curve (AUC), representing the accuracy of the model, across all 300 iterations was 0.775 (95 % CI [0.767,0.782]) with a median AUC of 0.787. The positive predictive value (PPV), representing how well the model predicted SSI when a patient had SSI, over all predictions was 92.56 % with a negative predictive value (NPV), representing how well the model predicted absence of SSI when a patient did not have SSI, of 98.45 %. In analyzing relative model weights, the five highest weighted variables were Congestive Heart Failure, Chronic Pulmonary Failure, Hemiplegia/Paraplegia, Multilevel Fusion and Cerebrovascular Disease respectively. Notable factors that were protective against infection were ICU Admission, Increasing Charlson Comorbidity Score, Race (White), and being male. Minimally invasive surgery (MIS) was also determined to be mildly protective., Conclusion: Machine learning and artificial intelligence are relevant and impressive tools that should be employed in the clinical decision making for patients. The variables with the largest model weights were primarily comorbidity related with the exception of multilevel fusion. Further study is needed, however, in order to draw any definitive conclusions., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: White matter volume loss may be an anatomic driver in the development of clinical symptoms in cervical spondylotic myelopathy (CSM). Considerably less attention has been devoted to gray matter (GM) injury. Newly developed atlas-based mapping techniques may allow evaluation of GM cord volume alterations in CSM., Methods: There were 29 subjects evaluated: 15 patients with CSM (61.1 ± 8.7 years old) and 14 age-matched control subjects (56.1 ± 5.3 years old). All subjects underwent 3T magnetic resonance imaging of the cervical spine. Post-processing with the Spinal Cord Toolbox (v3.0) provided GM volumetric analysis. Clinical scores collected included modified Japanese Orthopaedic Association, neck and arm numeric rating scales, Nurick Scale, and Neck Disability Index. All volumes were normalized to account for anatomic variability., Results: Normalized mean ventral GM volume in the compression region was significantly lower in patients compared with control subjects (1.103 ± 0.21 vs. 1.35 ± 0.32, P = 0.027). Normalized mean dorsal volume in the compression region was decreased in patients compared with control subjects (0.90 ± 0.17 vs. 1.04 ± 0.15, P = 0.049). GM volumes were associated with clinical scores, including Neck Disability Index, arm numeric rating scale, modified Japanese Orthopaedic Association, and Nurick Scale scores (P = 0.022, P = 0.004, P = 0.027, and P = 0.016)., Conclusions: GM volume loss may be evaluated through atlas-based post-processing techniques and may correlate with clinical symptoms in CSM., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Unplanned preventable hospital readmissions within 30 days are a great burden to patients and the healthcare system. With an estimated $41.3 billion spent yearly, reducing such readmission rates is of the utmost importance. With the widespread adoption of big data and machine learning, clinicians can use these analytical tools to understand these complex relationships and find predictive factors that can be generalized to future patients. The object of this study was to assess the efficacy of a machine learning algorithm in the prediction of 30-day hospital readmission after posterior spinal fusion surgery., Methods: The authors analyzed the distribution of National Surgical Quality Improvement Program (NSQIP) posterior lumbar fusions from 2011 to 2016 by using machine learning techniques to create a model predictive of hospital readmissions. A deep neural network was trained using 177 unique input variables. The model was trained and tested using cross-validation, in which the data were randomly partitioned into training (n = 17,448 [75%]) and testing (n = 5816 [25%]) data sets. In training, the 17,448 training cases were fed through a series of 7 layers, each with varying degrees of forward and backward communicating nodes (neurons)., Results: Mean and median positive predictive values were 78.5% and 78.0%, respectively. Mean and median negative predictive values were both 97%, respectively. Mean and median areas under the curve for the model were 0.812 and 0.810, respectively. The five most heavily weighted inputs were (in order of importance) return to the operating room, septic shock, superficial surgical site infection, sepsis, and being on a ventilator for > 48 hours., Conclusions: Machine learning and artificial intelligence are powerful tools with the ability to improve understanding of predictive metrics in clinical spine surgery. The authors' model was able to predict those patients who would not require readmission. Similarly, the majority of predicted readmissions (up to 60%) were predicted by the model while retaining a 0% false-positive rate. Such findings suggest a possible need for reevaluation of the current Hospital Readmissions Reduction Program penalties in spine surgery.

Introduction: Exercise-related injuries (ERIs) are a common cause of nonfatal emergency department and hospital visits. CrossFit is a high-intensity workout regimen whose popularity has grown rapidly. However, ERIs due to CrossFit remained under investigated., Methods: All patients who presented to the main hospital at a major academic center complaining of an injury sustained performing CrossFit between June 2010 and June 2016 were identified. Injuries were classified by anatomical location (eg, knee, spine). For patients with spinal injuries, data were collected including age, sex, body mass index (BMI), CrossFit experience level, symptom duration, type of symptoms, type of clinic presentation, cause of injury, objective neurological examination findings, imaging type, number of clinic visits, and treatments prescribed., Results: Four hundred ninety-eight patients with 523 CrossFit-related injuries were identified. Spine injuries were the most common injuries identified, accounting for 20.9%. Among spine injuries, the most common location of injury was the lumbar spine (83.1%). Average symptom duration was 6.4 months ± 15.1, and radicular complaints were the most common symptom (53%). A total of 30 (32%) patients had positive findings on neurologic examination. Six patients (6.7%) required surgical intervention for treatment after failing an average of 9.66 months of conservative treatment. There was no difference in age, sex, BMI, or duration of symptoms of patients requiring surgery with those who did not., Conclusions: CrossFit is a popular, high-intensity style workout with the potential to injure its participants. Spine injuries were the most common type of injury observed and frequently required surgical intervention.

Methods: Twenty patients with CSM and 17 controls were recruited. Clinical scores of modified Japanese Orthopedic Association (mJOA) and Nurick were collected. MRI based compression grades such as cord distortion were assessed. Hand dysfunction was tested using a custom motorized apparatus. Subject's forearm was placed in a cast and positioned such that their metacarpophalangeal (MCP) joint was vertically aligned with the motor shaft. Surface electromyographic sensors were placed on flexor digitorum superficialis (FDS) and extensor digitorum communis muscles. Hyperreflexia was measured as the FDS muscle activation during reflex when the MCP joint was moved from flexion to extension at 300°/sec. Proprioception was quantified as the angle of detection in absence of visual or auditory cues (subjects were blindfolded and given noise-cancelling headphones). Strength was measured as the maximum isometric force at the MCP joint. 2-sample t-test (p<0.05) were performed to assess significant differences in reflexes, proprioception and strength among patients and controls (SPSS software version 24)., Results: Patients reported higher Nurick (1.90±1.0 vs 0±0, p<0.001) and lower mJOA scores (14.3±1.9 vs 18.0±0, p<0.001) as compared to controls. Similarly, patients with CSM had increased reflexes (peak FDS EMG) (0.073±0.096 vs. 0.014±0.010, p = 0.019). Patient proprioception was significantly worse; mean angle of detection was greater than twice as high in patients (9.6± 9.43°) compared to controls (4.0± 2.3°), p = 0.022. MRI based compression ratio (CR) was a significant predictor of hyperreflexia, CR<0.44 resulted in steep increase in reflex activity. Fifteen of the 20 patients who completed follow up testing at 6 months after surgery show substantial clinical improvement in reflexes and proprioceptive angle, while repeated testing in controls were unchanged., Conclusion: In conclusion, hyperreflexia and decline in proprioception are the main drivers of hand disability in patients with CSM. Of multiple scales, only a select few MRI scales (such as compression ratio) were predictive of increased reflexes. The study describes a pre-clinical testing apparatus to quantitatively and objectively assess primary presenting symptoms in CSM. This pilot apparatus has the potential to evaluate treatment efficacy through repeated testing. Objective testing of hand dysfunction can help inform the design of clinically feasible devices, guide MRI biomarker analysis, and improve our understanding of the progression of neurological injury in this patient population., Competing Interests: The authors have declared that no competing interests exist.

Background: Cervical spondylotic myelopathy (CSM) severity and presence of symptoms are often difficult to predict based simply on clinical imaging alone. Similarly, improved machine learning techniques provide new tools with immense clinical potential., Methods: A total of 14 patients with CSM and 14 controls underwent imaging of the cervical spine. Two different artificial neural network models were trained; 1) to predict CSM diagnosis; and 2) to predict CSM severity. Model 1 consisted of 6 inputs including 3 common imaging scales for the evaluation of cord compression, alongside 3 objective magnetic resonance imaging measurements. The outcome for model 1 was binary to predict CSM diagnosis. Model 2 consisted of 23 input variables derived from probabilistic volume mapping measurements of white matter tracts in the region of compression. The outcome of model 2 was linear, to predict the modified Japanese Orthopedic Association (mJOA) score., Results: Model 1 was used in predicting CSM. The mean cross-validated accuracy of the trained model was 86.50% (95% confidence interval, 85.16%-87.83%) with a median accuracy of 90.00%. Area under the curve (AUC) was calculated for each repetition. Average AUC for each repetition was 0.947 with a median AUC of 1.0. Average sensitivity, specificity, positive predictive value, and negative predictive value were 90.25%, 85.05%, 81.58%, and 91.94%, respectively. Model 2 was used in modeling mJOA. The mJOA model predicted scores, with a mean and median error of -0.29 mJOA points and -0.08 mJOA points, respectively, mean error per batch was 0.714 mJOA points., Conclusions: Machine learning provides a promising method for prediction, diagnosis, and even prognosis in patients with CSM., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Venous thromboembolic events (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), are a major cause of readmission, morbidity, and mortality after spine surgery. Patients with spinal fractures are particularly at an increased risk for VTE. The objective of this study is to understand VTE risk factors in this patient population and to examine current institutional practices., Patients and Methods: We retrospectively examined records from 195 consecutive patients with spinal fractures who underwent spinal stabilization surgeries- amongst a cohort of 6869 patients who underwent spinal surgery. We collected data on patient demographics, surgery, hospital course, and 30-day rates of VTE, readmission, reoperation. Multivariable logistic regression was used to identify independent predictors of each outcome., Results: Among 195 patients undergoing surgery for spinal fractures, 9.2% experienced a VTE, compared to 2.3% among all other spine patients (OR 4.466, p < 0.0001). 48.7% spine fracture patients received chemoprophylactic anticoagulation, compared to 35.7% of all other spine patients (OR 2.657, p < 0.0001). Within 30 days of surgery, estimated blood loss (EBL) was associated with VTE (OR 1.001, p = 0.0415) and DVT (OR 1.001, p = 0.049), and comorbid cardiac disease burden showed a trend toward significance in predicting both VTE (OR 1.890, p = 0.0956) and DVT (OR 4.228, p = 0.0549). Number of levels in surgery predicted PE within 30 days of surgery (OR 1.573, p = 0.0107)., Conclusions: Compared to all other patients undergoing spine surgery, patients with spinal fractures are more likely to receive chemoprophylactic anticoagulation, but nevertheless have a higher rate of VTE events. EBL and comorbid disease burden predict VTE events in patients with spine fractures., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Cervical spondylotic myelopathy (CSM) is among the most common spinal cord disorders of the elderly. Muscle fat infiltration (MFI), a potential pathological sign of muscle adiposity, may contribute to or be associated with pain/disability/impairments in patients with CSM. We examined the relationship between MFI and CSM's clinical manifestations by enrolling nine CSM patients and five aged-matched controls to undergo MRI imaging of the cervical spine with MFI. A blinded investigator calculated MFI for each of the bilateral multifidii muscles from C3 to C7 on the MRI images. Nurick scores, Neck Disability Index, and modified Japanese Orthopedic Association scores were collected for all patients. CSM patients and controls were equivalent with respect to age, height, weight, gender, race, smoking status, and employment status. MFI was higher in patients with CSM than in controls (31.7% v. 24.6%, respectively, p = 0.0178). Higher MFI was associated with increased disability on the Nurick scale (p = 0.0371). MJOA scores correlated linearly with MFI (R = 0.542, p = 0.0453), but not NDI (p = 0.3125). Increased MFI of the multifidus muscles is associated with cervical myelopathy and a clinically significant decline in sensorimotor function as measured by mJOA and Nurick scores. Spinal injury in CSM may lead to secondary muscle loss and muscle fat infiltration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Study Design: Case-control., Objective: The aim of this study was to understand the role of high-resolution magnetic resonance (MR) in identifying regional cord volume loss in cervical spondylotic myelopathy (CSM)., Summary of Background Data: Preliminary studies suggest that compression of the ventral region of the cord may contribute disproportionately to CSM symptomology; however, tract-specific data are lacking in the CSM population. The current study is the first to use 3T MR imaging (MRI) images of CSM patients to determine specific volume loss at the level of detail of individual descending white matter tracts., Methods: Twelve patients with CSM and 14 age-matched were enrolled prospectively and underwent 3-Tesla MRI of the cervical spine. Using the high-resolution images of the spinal cord, straightening and alignment with a template was performed and specific spinal cord tract volumes were measured using Spinal Cord Tool-box version 3.0.7. Modified Japanese orthopedic association (mJOA) and Nurick disability scores were collected in a prospective manner and were analyzed in relation to descending spinal tract volumes., Results: Having CSM was predicted by anterior/posterior diameter, eccentricity of the cord [odds ratio (OR) 0.000000621, P = 0.004], ventral reticulospinal tract volume (OR 1.167, P = 0.063), lateral corticospinal tract volume (OR 1.034, P = 0.046), rubrospinal tract volume (OR 1.072, P = 0.011), and ventrolateral reticulospinal tract volume (OR 1.474, P = 0.005) on single variable logistic regression. Single variable linear regression showed decreases in anterior/posterior spinal cord diameter (P = 0.022), ventral reticulospinal tract volumes (P = 0.007), and ventrolateral reticulospinal tract volumes (P = 0.017) to significantly predict worsening mJOA scores. Similarly, decreases in ventral reticulospinal tract volumes significantly predicted increasing Nurick scores (P = 0.039)., Conclusion: High-resolution 3T MRI can detect tract-specific volume loss in descending spinal cord tracts in CSM patients. Anterior/posterior spinal cord diameter, ventral reticulospinal tract, ventrolateral reticulospinal tract, lateral corticospinal tract, and rubrospinal tract volume loss are associated with CSM symptoms., Level of Evidence: 2.

Study Design: A case-control study., Objective: The aim of this study was to understand the role of magnetization transfer ratio (MTR) in identifying patients with clinically significant myelopathy and disability., Summary of Background Data: MTR is a quantitative measure that correlates with myelin loss and neural tissue destruction in a variety of neurological diseases. However, the usefulness of MTR in patients with cervical spondylotic myelopathy (CSM) has not been examined., Methods: We prospectively enrolled seven CSM patients and seven age-matched controls to undergo magnetic resonance imaging (MRI) of the cervical spine. Nurick, Neck Disability Index (NDI), and modified Japanese Orthopedic Association (mJOA) scores were collected for all patients. Clinical hyperreflexia was tested at the MCP joint, using a six-axis load cell. Reflex was simulated by quickly moving the joint from maximum flexion to maximum extension (300°/second). Anterior, lateral, and posterior cord MTR measurements were compared with clinical outcomes., Results: Compared with controls, CSM patients had lower anterior cord MTR (38.29 vs. 29.97, Δ = -8.314, P = 0.0022), and equivalent posterior cord (P = 0.2896) and lateral cord (P = 0.3062) MTR. Higher Nurick scores were associated with lower anterior cord MTR (P = 0.0205), but not lateral cord (P = 0.5446) or posterior cord MTR (P = 0.1222). Lower mJOA was associated with lower anterior cord MTR (P = 0.0090), but not lateral cord (P = 0.4864) or posterior cord MTR (P = 0.4819). There was no association between NDI and MTR of the anterior (P = 0.4351), lateral (P = 0.7557), or posterior cord (P = 0.9171). There was a linear relationship between hyperreflexia and anterior cord MTR (slope = -117.3, R = 0.6598, P = 0.0379), but not lateral cord (P = 0.1906, R = 0.4511) or posterior cord (P = 0.2577, R = 0.3957) MTR., Conclusion: Anterior cord MTR correlates with clinical outcomes as measured by mJOA index, Nurick score, and quantitative hyperreflexia, and could play a role in the preoperative assessment of CSM., Level of Evidence: 2.

Study Design: Retrospective cohort study., Objective: The aim of the study was to determine readmission rates and predictors of readmission after posterior cervical fusion (PCF)., Summary of Background Data: PCFs are common spinal operations for a variety of spinal disorders including cervical myelopathy, unstable fractures, cervical deformity, and tumors. Data elaborating on risk factors for 30-day readmission are limited., Methods: Data were collected from the 2006 to 2013 American College of Surgeons National Surgical Quality Improvement Program database. Predictors of 30-day readmission comprising patient demographics, comorbidities, operative features, and postoperative complications were identified through logistic multivariable regression., Results: A total of 3401 patients met study criteria. Rate of 30-day readmission was 6.20%. Multilevel fusion was performed in 69.16% of patients. Postoperative infection was the most reason, accounting for 17.06% of all readmissions. Age older than 70 years (odds ratio [OR] = 1.61, P = 0.012), renal failure requiring dialysis (OR = 3.69, P = 0.011), anemia (OR = 1.57, P = 0.006), multilevel fusion (OR = 1.61, P = 0.012), surgical site infections (OR = 20.4, P < 0.001), wound dehiscence (OR = 19.08, P < 0.001), postoperative pneumonia (OR = 2.75, P = 0.01), pulmonary embolism (OR = 15.39, P < 0.001), and progressing renal insufficiency (OR = 10.13, P = 0.061) were significant predictors of hospital readmission., Conclusion: The identified predictors of readmission after PCF can improve patient counseling, identification of high-risk patients, and guide changes in healthcare delivery pathways. Patients with modifiable risk factors such as anemia and kidney failure may benefit from preoperative optimization. In addition, postoperative complications represent a key target for intervention., Level of Evidence: 3.

Background: Jefferson fractures, or burst fractures of the C1 vertebra, can be managed surgically or conservatively, depending on their stability., Methods: We identified all patients who were treated for a C1 fracture at our institution between 1999 and 2016 for retrospective analysis. Patients with any other concurrent cervical fractures or nontraumatic etiology of fracture were excluded. Stability was defined as either lateral mass displacement ≥7 mm on computed tomography or presence of transverse atlantal ligament disruption on magnetic resonance imaging. We collected data on patients' demographic, clinical, and radiographic presentation and identified variables independently associated with instability at presentation and failure to achieve fusion at follow-up., Results: We identified 65 patients. On multivariable regression, instability at presentation was independently associated with atlantodens interval (odds ratio [OR] 2.357, 95% confidence interval [CI] [0.0629-1.271], P = 0.099) and type 3 fracture (OR 6.081, 95% CI [1.068-34.612], P = 0.042). Failure to achieve fusion was independently associated with age (OR 1.226, 95% CI [1.007-1.495], P = 0.043), motor vehicle collision as mechanism of injury (OR 22834.3, 95% CI [3.135-1.66e8], P = 0.027), and type 2 fracture (OR 168.537, 95% CI [1.743-16292.92], P = 0.028). Type 3 fracture was positively associated with halo vest for management (OR 17.171, 95% CI [2.882-102.289], P = 0.002) and negatively associated with a rigid cervical collar for management (OR 0.0616, 95% CI [0.0104-0.3653], P = 0.002). All 4 patients who underwent surgery presented with unstable fracture (P = 0.0187)., Conclusions: Atlantodens interval, mechanism of injury, and fracture type affect Jefferson fracture management decisions and outcomes, including instability at presentation and fusion at follow-up. Most fractures were managed nonsurgically regardless of stability., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Readmission and reoperation are used as hospital and surgeon quality metrics. Venous thromboembolic (VTE) events, including deep vein thrombosis and pulmonary embolism (PE), are a major cause of readmission, morbidity, and mortality after spine surgery. Specific procedural, perioperative, and patient characteristics may be associated with these outcomes., Methods: We retrospectively examined records from 6869 consecutive spine surgeries at our institution. We collected data on patient demographics, surgery, hospital course, and 30-day rates of VTE, readmission, reoperation, and epidural hematoma. Stepwise multivariable logistic regression was used to identify independent predictors of each outcome., Results: Factors associated with VTE within 30 days of surgery include a history of VTE (odds ratio [OR] 3.92 [confidence interval 1.83-8.36], P < 0.001), estimated blood loss (EBL; OR 1.017 [1.005-1.029], P = 0.004), fracture (OR 5.42 [2.09-14.05], P = 0.001), history of PE (OR 4.04 [1.22-13.42], P = 0.023), and transfusion (OR 2.26 [1.07-4.77], P = 0.033). Factors associated with readmission were a history of PE (OR 3.27 [1.07-9.97], P = 0.038), PE (OR 8.07 [2.26-28.8], P = 0.001), transfusion (OR 2.54 [1.55-4.17], P < 0.001), comorbid disease burden (OR 1.35 [1.01-1.80], P = 0.041), and tumor surgery (OR 2.84 [1.32-6.10], P = 0.007). Factors associated with reoperation were EBL (OR 1.024 [1.006-1.042], P = 0.008), transfusion (OR 3.86 [1.38-10.79], P = 0.01), and PE (OR 6.05 [1.03-35.62], P = 0.046). Transfusion was associated with epidural hematoma within 30 days (OR 7.38 [1.37-39.83], P = 0.02)., Conclusions: Transfusion and EBL are associated with numerous negative outcomes. Transfusion is an independent predictor of VTE, readmission, reoperation, and epidural hematoma requiring evacuation. Specific pathologies were associated with specific negative outcomes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: Multicenter propensity score-adjusted retrospective cohort study., Objective: To determine baseline 30-day complication rates for anterior cervical discectomy and fusion (ACDF) and compare clinical complications for patients undergoing single-level ACDFs between inpatient and outpatient settings., Summary of Background Data: ACDF remains the most common procedure in the treatment of a variety of cervical disc pathologies, making it a focus of quality improvement initiatives. Outpatient single-level ACDFs are becoming more common and offer advantages including reducing nosocomial infections and costs, as well as improved patient satisfaction., Materials and Methods: The 2011-2013 NSQIP datasets were queried to identify all patients who underwent single-level ACDF procedures using current procedural terminology codes. Outpatient and inpatient cohorts were matched 1:1 using propensity score analysis to assess short-term outcomes. The outcomes assessed included 30-day medical and surgical complications, reoperation, readmission, and mortality., Results: In total, 6940 patients underwent a single-level ACDF with an overall complication rate of 4.2%. A total of 5162 patients (74.4%) had an inpatient hospital stay after surgery, whereas 1778 patients (25.6%) had outpatient surgery. After matching based on preoperative and operative characteristics to account for potential confounders, the overall complication rate was higher in the inpatient arm compared with the outpatient arm (2.5% vs. 1.2%; P=0.003). The 30-day readmission rate was also higher but not significant in the inpatient group than the outpatient group (2.2% vs. 1.8%; P=0.355). Mortality was the same with 0.1% in both groups (P=0.564)., Conclusions: Patients undergoing outpatient single-level ACDF had a lower 30-day complication rates than those undergoing it in the inpatient setting. Outpatient surgery for single-level ACDF is safe and a favorable option for suitable patients., Level of Evidence: Level 3.

Purpose: In this article, we summarize our work on understanding the influence of cervical sagittal malalignment on the mechanics of the cervical spine., Methods: Biomechanical studies were performed using an ex vivo laboratory model to study the kinematic and kinetic response of human cervical spine specimens in the setting of cervical sagittal imbalance. The model allowed controlled variations of C2-C7 Sagittal Vertical Alignment (C2-C7 SVA) and T1-Slope so that clinically relevant sagittally malaligned profiles could be prescribed, while maintaining horizontal gaze, and their biomechanical consequences studied., Results: Our results demonstrated that increasing C2-C7 SVA caused flexion of lower cervical (C2-C7) segments and hyperextension of suboccipital (C0-C1-C2) segments to maintain horizontal gaze. An increase in C2-C7 SVA increased the lower cervical neural foraminal areas. Conversely, increasing T1-slope predominantly influenced subaxial cervical lordosis and, as a result, decreased cervical neural foraminal areas. Therefore, we believe patients with increased upper thoracic kyphosis and radicular symptoms may respond with increased forward head posture (FHP) as a compensatory mechanism to increase their lower cervical neural foraminal area and alleviate nerve root compression as well as reduce the burden on posterior muscles and soft and bony structures of the cervical spine. Increasing FHP (i.e., increased C2-C7 SVA) was associated with shortening of the cervical flexors and occipital extensors and lengthening of the cervical extensors and occipital flexors, which corresponds to C2-C7 flexion and C0-C2 extension. The greatest shortening occurred in the suboccipital muscles, suggesting considerable load bearing of these muscles during chronic FHP. Regardless, there was no evidence of nerve compression within the suboccipital triangle. Finally, cervical sagittal imbalance may play a role in exacerbating adjacent segment pathomechanics after multilevel cervical fusion and should be considered during surgical planning., Conclusions: The results of our biomechanical studies have improved our understanding of the impact of cervical sagittal malalignment on pathomechanics of the cervical spine. We believe this improved understanding will assist in clinical decision-making.

Background: The effects of chronic corticosteroid therapy on complications, readmission, and reoperation after posterior lumbar fusion (PLF) remain underinvestigated, and were examined to determine differences in outcomes., Methods: We analyzed patients undergoing PLF between 2006 and 2013 using the National Surgery Quality Improvement Program database (NSQIP). Patients taking steroids for a chronic condition were compared with those not taking steroids. Multivariable regression identified factors independently associated with complications, readmission, and reoperation. A risk score was calculated for predicting complications., Results: A total of 8492 patients were identified, of whom 353 used steroids. The patients using steroids were older (mean age, 65.4 years vs. 61.0 years; P < 0.001), were more likely to be female (61.2% vs. 55.1%; P = 0.025), had a higher American Society of Anesthesiologists class (P < 0.001), were less likely to be functionally independent (90.3% vs. 96.5%; P < 0.001), and were more likely to have a history of hypertension (69.1% vs. 58.3%; P < 0.001), diabetes mellitus (21.8% vs. 17.4%; P = 0.033), cardiac disease (74.8% vs. 66.1%; P = 0.001), and/or severe chronic obstructive pulmonary disease (10.5% vs. 4.2%; P < 0.001). The rates of readmission (9.4% vs. 6.0%; P = 0.023), reoperation (6.5% vs. 3.6%; P = 0.004), overall complications (14.5% vs. 9.6%; P = 0.003), and infections (9.6% vs. 5.1%; P < 0.001) were higher in the steroid group. On multivariable regression, steroids were independently associated with overall complications (odds ratio [OR], 1.38; P = 0.044) and infectious complications (OR, 1.65; P < 0.001), but not with medical complications, readmission, or reoperation. Patients with higher risk scores had higher complication rates., Conclusions: The use of corticosteroid therapy is associated with a moderately increased risk of overall complications, but no association was found with readmission or reoperation., (Copyright © 2017. Published by Elsevier Inc.)

Objective: Recently, minimally invasive surgery (MIS) has been included among the treatment modalities for scoliosis. However, literature comparing MIS to open surgery for scoliosis correction is limited. The objective of this study was to compare outcomes for scoliosis correction patients undergoing MIS versus open approach., Methods: We retrospectively collected data on demographics, procedure characteristics, and outcomes for 207 consecutive scoliosis correction surgeries at our institution between 2009 and 2015., Results: MIS patients had lower number of levels fused ( p < 0.0001), shorter surgeries ( p = 0.0023), and shorter overall lengths of stay ( p < 0.0001), were less likely to be admitted to the ICU ( p < 0.0001), and had shorter ICU stays ( p = 0.0015). On multivariable regression, number of levels fused predicted selection for MIS procedure ( p = 0.004), and multiple other variables showed trends toward significance. Age predicted ICU admission and VTE. BMI predicted any VTE, and DVT specifically. Comorbid disease burden predicted readmission, need for transfusion, and ICU admission. Number of levels fused predicted prolonged surgery, need for transfusion, and ICU admission., Conclusions: Patients undergoing MIS correction had shorter surgeries, shorter lengths of stay, and shorter and fewer ICU stays, but there was a significant selection effect. Accounting for other variables, MIS did not independently predict any of the outcomes.

Study Design: Retrospective cohort study., Objective: To determine whether receipt of blood transfusion and preoperative anemia are associated with increased rates of 30-day all-cause readmission, and secondarily with a prolonged hospital stay after spinal surgery., Summary of Background Data: Increased focus on health care quality has led to efforts to determine postsurgical readmission rates and predictors of length of postoperative hospital stay. Although there are still no defined outcome measures specific to spinal surgery to which providers are held accountable, efforts to identify appropriate measures and to determine modifiable risk factors to optimize quality are ongoing., Methods: Records from 1187 consecutive spinal surgeries at Northwestern Memorial Hospital in 2010 were retrospectively reviewed and data were collected that described the patient, surgical procedure, hospital course, complications, and readmissions. Presence or absence of transfusion during the surgery and associated hospital course was treated as a binary variable. Multivariate negative binomial regression and logistic regression were used to model length of stay and readmission, respectively., Results: Nearly one fifth (17.8%) of surgeries received transfusions, and the overall readmission rate was 6.1%. After controlling for potential confounders, we found that the presence of a transfusion was associated with a 60% longer hospital stay [adjusted incidence rate ratio=1.60 (1.34-1.91), P<0.001], but was not significantly associated with an increased rate of readmission [adjusted odds ratio=0.81 (0.39-1.70), P=0.582]. Any degree of preoperative anemia was associated with increased length of stay, but only severe anemia was associated with an increased rate of readmission., Conclusions: Both receipt of blood transfusion and any degree of preoperative anemia were associated with increased length of hospital stay after controlling for other variables. Severe anemia, but not receipt of blood transfusion, was associated with increased rate of readmission. Our findings may help define actions to reduce length of stay and decrease rates of readmission.

Study Design: Multicenter prospective pilot study., Objective: To evaluate if continuous physical activity monitoring by a personal electronic 3-dimensional accelerometer device is feasible and can provide objective data that correlates with patient-reported outcomes following spine surgery., Summary of Background Data: Self-reported health-related quality-of-life (HRQOL) metrics are inherently limited by being very subjective, having a low frequency of data collection, and inconsistent follow-up., Methods: Inclusion criteria: adults (18+), thoracolumbar deformity or degenerative disease, and regular access to a computer with internet connection. Physical activity parameters included: number of daily steps, maximum hourly steps, and activity intensity. Patients completed the Oswestry Disability Index (ODI), the Short-Form Health Survey 36 (SF-36), and the Scoliosis Research Society-22r (SRS22) preoperatively and postoperatively at 6 weeks, 3 months, and 6 months., Results: Thirty-two patients were enrolled, 8 (25%) withdrew, 1 (3.1%) died, and 1 (3.1%) did not end up undergoing surgery resulting in 22 (68.8%) available patients. Mean preoperative and postoperative step ranges were 1278±767 to 17,800±6464 and 891±587 to 12,655±7038, respectively. Eleven patients improved in mean total daily steps at the final postoperative month with 2 having significant improvements (P<0.05). Five patients did not significantly change (P>0.05) and 6 patients had significantly lower mean total daily steps at 6 months (P<0.05). The entire cohort significantly improved in ODI, SF-36 Physical Component Summary, SRS Activity, SRS Appearance, SRS Mental, SRS Satisfaction, and SRS Total score at 6 months postoperative (P<0.05 for all). Both ODI and Physical Component Summary were significantly correlated with preoperative average total daily steps (r=-0.61, P=0.0058 and r=0.60, P=0.0114, respectively). No other HRQOL metrics were significantly correlated at baseline or at 6 months postoperative (P>0.05)., Conclusions: A prospective pilot study for continuous real-time physical activity monitoring was successfully completed. This is the first study of its kind and demonstrates a foundation to continuous physical activity monitoring following spine surgery. A larger and longer prospective study is needed to confirm long-term results and its relationship with HRQOL scores.

OBJECTIVE Venous thromboembolism (VTE) after spinal surgery is a major cause of morbidity, but chemoprophylactic anticoagulation can prevent it. However, there is variability in the timing and use of chemoprophylactic anticoagulation after spine surgery, particularly given surgeons' concerns for spinal epidural hematomas. The goal of this study was to provide insight into the safety, efficacy, and timing of anticoagulation therapy after spinal surgery. METHODS The authors retrospectively examined records from 6869 consecutive spinal surgeries performed in their departments at Northwestern University. Data on patient demographics, surgery, hospital course, timing of chemoprophylaxis, and complications, including deep venous thrombosis (DVT), pulmonary embolism (PE), and spinal epidural hematomas requiring evacuation, were collected. Data from the patients who received chemoprophylaxis (n = 1904) were compared with those of patients who did not (n = 4965). The timing of chemoprophylaxis, the rate of VTEs, and the incidence of spinal epidural hematomas were analyzed. RESULTS The chemoprophylaxis group had more risk factors, including greater age (59.70 vs 51.86 years, respectively; p < 0.001), longer surgery (278.59 vs 145.66 minutes, respectively; p < 0.001), higher estimated blood loss (995 vs 448 ml, respectively; p < 0.001), more comorbid diagnoses (2.69 vs 1.89, respectively; p < 0.001), history of VTE (5.8% vs 2.1%, respectively; p < 0.001), and a higher number were undergoing fusion surgery (46.1% vs 24.7%, respectively; p < 0.001). The prevalence of VTE was higher in the chemoprophylaxis group (3.62% vs 2.03%, respectively; p < 0.001). The median time to VTE occurrence was shorter in the nonchemoprophylaxis group (3.6 vs 6.8 days, respectively; p = 0.0003, log-rank test; hazard ratio 0.685 [0.505-0.926]), and the peak prevalence of VTE occurred in the first 3 postoperative days in the nonchemoprophylaxis group. The average time of initiation of chemoprophylaxis was 1.46 days after surgery. The rates of epidural hematoma were 0.20% (n = 4) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.622). CONCLUSIONS The risks of spinal epidural hematoma among patients who receive chemoprophylaxis and those who do not are low and equivalent. Administering anticoagulation therapy from 1 day before to 3 days after surgery is safe for patients at high risk for VTE.

Study Design: A systematic review., Objective: The available literature on interspinous rigid fixation/fusion devices (IFD) was systematically reviewed to explore the devices' efficacy and complication profile., Summary of Background Data: The clinical application of new spinal technologies may proceed without well-established evidence, as is the case with IFDs. IFDs are plate-like devices that are attached to the lateral aspects of 2 adjacent spinous processes to promote rigidity at that segment. Despite almost a decade since the devices' introduction, the literature regarding efficacy and safety is sparse. Complications have been reported but no definitive study is known to the authors., Methods: A systematic review of the past 10 years of English literature was conducted according to PRISMA guidelines. The timeframe was chosen based on publication of the first study containing a modern IFD, the SPIRE, in 2006. All PubMed publications containing MeSH headings or with title or abstract containing any combination of the words "interspinous," "spinous process," "fusion," "fixation," "plate," or "plating" were included. Exclusion criteria consisted of dynamic stabilization devices (X-Stop, DIAM, etc.), cervical spine, pediatrics, and animal models. The articles were blinded to author and journal, assigned a level of evidence by Oxford Centre of Evidence-Based Medicine (OCEBM) criteria, and summarized in an evidentiary table., Results: A total of 293 articles were found in the initial search, of which 15 remained after examination for exclusion criteria. No class I or class II evidence regarding IFDs was found. IFDs have been shown by methodologically flawed and highly biased class III evidence to reduce instability at 1 year, without statistical comparison of complication rates against other treatment modalities., Conclusions: Although IFDs are heavily marketed and commonly applied in modern practice, data on safety and efficacy are inadequate. The paucity of evidence warrants reexamination of these devices' value and indications by the spine surgery community.

Background: Management of combination fractures of the atlas and axis varies from nonoperative immobilization to selective early surgical intervention. In this study, we present our experience in managing these injuries., Materials and Methods: Electronic databases from two level 1 trauma centers were queried to identify all patients diagnosed with C1-C2 combination fractures from 2009 to present. Patient demographics, fracture characteristics, treatment modality, complications, Frankel scores, and fusion status were collected. Patients were separated into operative and nonoperative cohorts, and comparisons were made between the two groups., Results: Forty-eight patients were included, of which 19 received operative management and 29 were treated nonoperatively. The mean age was 76.1 and 75.3 years, respectively ( P = 0.877). Frankel grade distribution was similar on presentation in both groups, with most being neurologically intact. C1 fractures of both the anterior and posterior arch were present in 41.2% patients undergoing fusions compared to 27.6% of patients treated nonoperatively. No significant differences in comorbidities, neurologic deficits, or radiographic measurements were observed across the two groups., Conclusions: This study demonstrates the variety of treatment strategies used for the management of combined C1-C2 fractures. Patients managed operatively tend to have both anterior and posterior C1 arch fractures, while patients managed nonoperatively tend to have either anterior or posterior arch fractures. In general, treatments should be tailored to patients' needs depending on the stability of the fractures, neurological state, and medical comorbidities., Competing Interests: There are no conflicts of interest.

Study Design: Retrospective cohort study., Objective: To describe the readmission rate and identify risk factors associated with 30-day readmission after transforaminal lumbar interbody fusion (TLIF) surgery., Methods: Patients who underwent elective single level TLIF surgery from 2011 to 2013 were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Emergency or trauma cases were excluded. Preoperative, intraoperative, and postoperative variables were extracted. A multivariate binary regression identified predictors correlated with 30-day readmission., Results: A total of 4992 patients were included in the analysis. The overall 30-day readmission rate was 5.51% (275/4992) for readmissions reported between 2011 to 2013. The mean age of patients readmitted was 62.40 years (standard error [SE] = 0.78) and 60.92 years (SE = 0.20) among those whom were not readmitted ( P = .05). The top three causes for readmission included postoperative pain control, deep or superficial surgical site infections. Predictors associated with 30-day readmission in a multivariate analysis included female gender (odds ratio [OR] = 1.27, 95% CI = 0.97-1.65), history of severe chronic obstructive pulmonary disease (OR = 1.81, 95% CI = 1.11-2.96), and in the postoperative period, American Society of Anesthesiologists class (OR = 1.30, 95% CI = 1.04-1.63), presence of superficial surgical site infection (OR= 18.23, 95% CI = 10.36-32.08), or urinary tract infection (OR = 4.93, 95% CI = 2.84-8.58)., Conclusions: The readmission rate, risk factors, and causes following TLIF surgery are comparable to other lumbar spinal procedures reported from the ACS-NSQIP database., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Competing Interests: There are no conflicts of interest.

Study Design: Retrospective multicenter case series study., Objective: Because cervical dural tears are rare, most surgeons have limited experience with this complication. A multicenter study was performed to better understand the presentation, treatment, and outcomes following cervical dural tears., Methods: Multiple surgeons from 23 institutions retrospectively identified 21 rare complications that occurred between 2005 and 2011, including unintentional cervical dural tears. Demographic data and surgical history were obtained. Clinical outcomes following surgery were assessed, and any reoperations were recorded. Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA), Nurick classification (NuC), and Short-Form 36 (SF36) scores were recorded at baseline and final follow-up at certain centers. All data were collected, collated, and analyzed by a private research organization., Results: There were 109 cases of cervical dural tears among 18 463 surgeries performed. In 101 cases (93%) there was no clinical sequelae following successful dural tear repair. There were statistical improvements ( P < .05) in mJOA and NuC scores, but not NDI or SF36 scores. No specific baseline or operative factors were found to be associated with the occurrence of dural tears. In most cases, no further postoperative treatments of the dural tear were required, while there were 13 patients (12%) that required subsequent treatment of cerebrospinal fluid drainage. Analysis of those requiring further treatments did not identify an optimum treatment strategy for cervical dural tears., Conclusions: In this multicenter study, we report our findings on the largest reported series (n = 109) of cervical dural tears. In a vast majority of cases, no subsequent interventions were required and no clinical sequelae were observed., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Kevin R. O'Neill reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AOSpine, grants from AOSpine North America, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Michael P. Steinmetz reports grants from AOSpine North America during the conduct of the study; Praveen V. Mummaneni reports grants from AOSpine North America during the conduct of the study, other from Depuy Spine, grants and other from AOSpine, other from Globus, other from Springer Publishers, other from Thieme Publishers, other from Taylor and Francis Publishers, other from Spincity/ISD, outside the submitted work; Dean Chou reports grants from AOSpine North America during the conduct of the study, other from Globus, other from Orthofix, other from Medtronic, outside the submitted work; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; Sheeraz A. Qureshi reports grants from AOSpine North America during the conduct of the study, and is a consultant and receive royalties from Stryker Spine, Biomet Spine, and RTI; Evan O. Baird reports grants from AOSpine North America during the conduct of the study; Justin S. Smith reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Nuvasive, personal fees from Cerapedics, personal fees from K2M, personal fees from Globus, personal fees from DePuy, outside the submitted work; Christopher Shaffrey reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Medtronic, from Nuvasive, personal fees from K2M, personal fees from Stryker, outside the submitted work, and Editorial Board Spine, Spinal Deformity and Neurosurgery; Chadi A. Tannoury reports grants from AOSpine North America during the conduct of the study; Tony Tannoury reports grants from AOSpine North America during the conduct of the study; Ziya L. Gokaslan reports grants from AOSpine North America during the conduct of the study, grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Jeffrey L. Gum reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, Alphatec, Stryker, LifeSpine, Acuity, Pacira, PAKmed, Gerson Lehrman Group, personal fees from OREF, AOSpine, personal fees from Acuity, other from Medtronic, personal fees from MiMedx, Pacira Pharmaceuticals, Alphatec, grants from Fischer Owen Fund, nonfinancial support from American Journal of Orthopaedics, nonfinancial support from American Journal of Orthopaedics, The Spine Journal, outside the submitted work; Robert A. Hart reports grants from AOSpine North America during the conduct of the study, other from CSRS Board, other from ISSLS, other from ISSG Executive Commitee, personal fees from DepuySynthes, personal fees from Globus, personal fees from Medtronic, other from Evans, Craven & Lackie, other from Benson, Bertoldo, Baker, & Carter, grants from Medtronic, grants from ISSGF, personal fees from Seaspine, personal fees from DepuySynthes, other from Spine Connect, personal fees from DepuySynthes, outside the submitted work; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; David B. Bumpass reports grants from AOSpine North America during the conduct of the study, grants from North American Spine Society, personal fees from Doximity, personal fees from Gerson Lehrman Group, outside the submitted work; Adeeb Derakhshan reports grants from AOSpine North America during the conduct of the study; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark Consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; Jonathan R. Pace reports grants from AOSpine North America during the conduct of the study; Gabriel A. Smith reports grants from AOSpine North America during the conduct of the study; Khoi D. Than reports grants from AOSpine North America during the conduct of the study; K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, non-financial support from Broadwater, outside the submitted work.

Study Design: Retrospective cohort study., Objective: The objective of the study was to determine rates of medical and surgical postoperative complications following anterior lumbar interbody fusion (ALIF) along with their associated predictors., Methods: Using the American College of Surgeons National Surgical Quality Improvement database, patients who underwent single-level ALIF surgery from 2006 to 2013 were identified. The 30-day rate of postoperative medical and surgical complications along with associated risk factors were evaluated by multivariable logistic regression., Results: In total, 1474 patients were included in the analysis. The overall rate of complications was 14.5%. The medical complication rate was 12.7%, while the surgical complication rate was 2.8%. Predictors of surgical complications were diabetes (odds ratio [OR] = 2.79, 95% CI = 1.20-6.01, P = .009), corticosteroid dependence (OR = 4.94, 95% CI = 1.73-14.08, P = .003), and preoperative transfusion of >4 units (OR = 7.12, 95% CI = 1.43-35.37, P = .016). Predictors of medical complications were longer operative times (OR = 4.25, 95% CI = 2.90-6.24, P < .001), preoperative anemia (OR = 2.29, 95% CI = 1.50-3.50, P < .001), >10% weight loss prior to surgery (OR = 6.79, 95% CI = 1.01-45.93, P = .049), and more severe American Society of Anesthesiologists classification (OR = 2.18, 95% CI = 1.54-3.11, P < .001)., Conclusions: The present study determines postoperative medical and surgical complications among patients undergoing ALIF. The risk factors elucidated in this study indicate that clinical practices to curtail complications should be targeted toward patients with preoperative anemia, weight loss, corticosteroid dependence, and toward those at risk for perioperative transfusions., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Study Design: Retrospective, multicenter case-series study and literature review., Objectives: To determine the prevalence of brachial plexopathy after cervical spine surgery and to review the literature to better understand the etiology and risk factors of brachial plexopathy after cervical spine surgery., Methods: A retrospective case-series study of 12 903 patients at 21 different sites was performed to analyze the prevalence of several different complications, including brachial plexopathy. A literature review of the US National Library of Medicine and the National Institutes of Health (PubMed) database was conducted to identify articles pertaining to brachial plexopathy following cervical spine surgery., Results: In our total population of 12 903 patients, only 1 suffered from postoperative brachial plexopathy. The overall prevalence rate was thus 0.01%, but the prevalence rate at the site where this complication occurred was 0.07%. Previously reported risk factors for postoperative brachial plexopathy include age, anterior surgical procedures, and a diagnosis of ossification of the posterior longitudinal ligament. The condition can also be due to patient positioning during surgery, which can generally be detected via the use of intraoperative neuromonitoring., Conclusions: Brachial plexopathy following cervical spine surgery is rare and merits further study., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Khoi D. Than reports grants from AOSpine North America during the conduct of the study; Praveen V. Mummaneni reports grants from AOSpine North America during the conduct of the study, other from Depuy Spine, grants and other from AOSpine, other from Globus, other from Springer Publishers, other from Thieme Publishers, other from Taylor and Francis Publishers, other from Spincity/ISD, outside the submitted work; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AO Spine, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America, during the conduct of the study; Paul M. Arnold reports grants from AOSpine North America, during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work.

Study Design: A multicenter, retrospective review of C5 palsy after cervical spine surgery., Objective: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery., Methods: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ 2 tests or Fisher exact tests for categorical variables., Results: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%)., Conclusion: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Sara E. Thompson reports grants from AOSpine North America during the conduct of the study; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AOSpine, grants from AOSpine North America during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; David E. Fish reports grants from AOSpine North America during the conduct of the study; Jeffrey C. Wang reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Chadi A. Tannoury reports grants from AOSpine North America during the conduct of the study; Tony Tannoury reports grants from AOSpine North America during the conduct of the study; P. Justin Tortolani reports grants from AOSpine North America during the conduct of the study, other from Globus Medical, grants from Spineology, other from Innovasis, outside the submitted work, and in addition, Dr. Tortolani has a patent Globus with royalties paid; Vincent C. Traynelis reports grants from AOSpine North America during the conduct of the study, and Medtronic – Royalties, Consultant Globus – Institutional Fellowship Support; Ziya Gokaslan reports grants from AOSpine North America during the conduct of the study, grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Alan S. Hilibrand reports grants from AOSpine North America during the conduct of the study, other from Amedica, Vertiflex, Benvenue, Lifespine, Paradigm Spine, PSD, Spinal Ventures, outside the submitted work, and in addition, Dr. Hilibrand has a patent Aesculap, Amedica, Biomet, Stryker, Alphatec, with royalties paid; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; Praveen V. Mummaneni reports grants from AOSpine North America during the conduct of the study, other from Deputy Spine, grants and other from AOSpine, other from Globus, other from Springer Publishers, other from Thieme Publishers, other from Taylor and Francis Publishers, other from Spincity/ISD, outside the submitted work; Dean Chou reports grants from AOSpine North America during the conduct of the study, other from Globus, other from Medtronic, other from Orthofix, outside the submitted work; Sheeraz A. Qureshi reports grants from AOSpine North America during the conduct of the study, and is a consultant and receives royalties from Stryker Spine, Biomet Spine, and RTI; Evan O. Baird reports grants from AOSpine North America during the conduct of the study; Zorica Buser reports grants from AOSpine North America during the conduct of the study; Michelle J. Clarke reports grants from AOSpine North America during the conduct of the study; Adeeb Derakhshan reports grants from AOSpine North America during the conduct of the study; Elizabeth L. Lord reports grants from AOSpine North America during the conduct of the study; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; Michael P. Steinmetz reports grants from AOSpine North America during the conduct of the study; Jonathan Pace reports grants from AOSpine North America during the conduct of the study; Peter I. Cha reports grants from AOSpine North America during the conduct of the study; Erica L. Gee reports grants from AOSpine North America during the conduct of the study; D. Alex Stroh reports grants from AOSpine North America during the conduct of the study; Khoi D. Than reports grants from AOSpine North America during the conduct of the study; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Samuel K. Cho reports grants from AOSpine North America during the conduct of the study; grants from OREF, personal fees from Stryker, from Medtronic, personal fees from DePuy Synthes, outside the submitted work; Rick C. Sasso reports grants from AOSpine North America during the conduct of the study; personal fees from medtronic, grants from medtronic, grants from K2, outside the submitted work; Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Mohamad Bydon reports grants from AOSpine North America during the conduct of the study; Anthony F. De Giacomo reports grants from AOSpine North America during the conduct of the study; Bruce Jobse reports grants from AOSpine North America during the conduct of the study; Daniel Lubelski reports grants from AOSpine North America during the conduct of the study; Mark Corriveau reports grants from AOSNA during the conduct of the study; Sungho Lee reports grants from AOSpine North America during the conduct of the study; Dhananjay Chatterjee reports grants from AOSpine North America during the conduct of the study; Erik N. Mayer reports grants from AOSpine North America during the conduct of the study; Owen J. McBride reports grants from AOSpine North America during the conduct of the study; Allison K. Roe reports grants from AOSpine North America during the conduct of the study; Marisa Y. Yanez reports grants from AOSpine North America during the conduct of the study.

Study Design: A multicentered retrospective case series., Objective: To determine the incidence and circumstances surrounding the development of a symptomatic postoperative epidural hematoma in the cervical spine., Methods: Patients who underwent cervical spine surgery between January 1, 2005, and December 31, 2011, at 23 institutions were reviewed, and all patients who developed an epidural hematoma were identified., Results: A total of 16 582 cervical spine surgeries were identified, and 15 patients developed a postoperative epidural hematoma, for a total incidence of 0.090%. Substantial variation between institutions was noted, with 11 sites reporting no epidural hematomas, and 1 site reporting an incidence of 0.76%. All patients initially presented with a neurologic deficit. Nine patients had complete resolution of the neurologic deficit after hematoma evacuation; however 2 of the 3 patients (66%) who had a delay in the diagnosis of the epidural hematoma had residual neurologic deficits compared to only 4 of the 12 patients (33%) who had no delay in the diagnosis or treatment ( P = .53). Additionally, the patients who experienced a postoperative epidural hematoma did not experience any significant improvement in health-related quality-of-life metrics as a result of the index procedure at final follow-up evaluation., Conclusion: This is the largest series to date to analyze the incidence of an epidural hematoma following cervical spine surgery, and this study suggest that an epidural hematoma occurs in approximately 1 out of 1000 cervical spine surgeries. Prompt diagnosis and treatment may improve the chance of making a complete neurologic recovery, but patients who develop this complication do not show improvements in the health-related quality-of-life measurements., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Gregory D. Schroeder reports grants from AOSpine North America during the conduct of the study, other from AOSpine, grants from Medtronic, outside the submitted work; Alan S. Hilibrand reports grants from AOSpine North America during the conduct of the study, other from Amedica, Vertiflex, Benvenue, Lifespine, Paradigm Spine, PSD, Spinal Ventures, outside the submitted work, and in addition, Dr. Hilibrand has a patent Aesculap, Amedica, Biomet, Stryker, Alphatec, with royalties paid; David E. Fish reports grants from AOSpine North America during the conduct of the study; Jeffrey C. Wang reports grants from AOSpine North America during the conduct of the study; Jeffrey L. Gum reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, Alphatec, Stryker, LifeSpine, Acuity, Pacira, PAKmed, Gerson Lehrman Group, personal fees from OREF, AOSpine, personal fees from Acuity, other from Medtronic, personal fees from MiMedx, Pacira Pharmaceuticals, Alphatec, grants from Fischer Owen Fund, nonfinancial support from American Journal of Orthopaedics, nonfinancial support from American Journal of Orthopaedics, The Spine Journal, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Ziya L. Gokaslan reports grants from AOSpine North America during the conduct of the study, grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; Thomas E. Mroz reports other from AOSpine, grants from AOSpine North America during the conduct of the study; personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Zorica Buser reports grants from AOSpine North America during the conduct of the study; Peter I. Cha reports grants from AOSpine North America during the conduct of the study; Erica L. Gee reports grants from AOSpine North America during the conduct of the study; Elizabeth L. Lord reports grants from AOSpine North America during the conduct of the study; Erik N. Mayer reports grants from AOSpine North America during the conduct of the study; Owen J. McBride reports grants from AOSpine North America during the conduct of the study; Emily C. Nguyen reports grants from AOSpine North America during the conduct of the study; P. Justin Tortolani reports grants from AOSpine North America during the conduct of the study, other from Globus Medical, grants from Spineology, other from Innovasis, outside the submitted work, and in addition, Dr. Tortolani has a patent Globus with royalties paid; D. Alex Stroh reports grants from AOSpine North America, during the conduct of the study; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Rick C. Sasso reports grants from AOSpine North America during the conduct of the study; personal fees from medtronic, grants from medtronic, grants from K2, outside the submitted work; Mohamad Bydon reports grants from AOSpine North America during the conduct of the study; Dhananjay Chatterjee reports grants from AOSpine North America during the conduct of the study; Allison K. Roe reports grants from AOSpine North America during the conduct of the study; D. Alex Stroh reports grants from AOSpine North America during the conduct of the study; Marisa Y. Yanez reports grants from AOSpine North America during the conduct of the study.

Study Design: Retrospective multi-institutional case series., Objective: The anterior cervical discectomy and fusion (ACDF) affords the surgeon the flexibility to treat a variety of cervical pathologies, with the majority being for degenerative and traumatic indications. Limited data in the literature describe the presentation and true incidence of postoperative surgical site infections., Methods: A retrospective multicenter case series study was conducted involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network, selected for their excellence in spine care and clinical research infrastructure and experience. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, inclusive, were reviewed to identify the occurrence of 21 predefined treatment complications. Patients who underwent an ACDF were identified in the database and reviewed for the occurrence of postoperative anterior cervical infections., Results: A total of 8887 patients were identified from a retrospective database analysis of 21 centers providing data for postoperative anterior cervical infections (17/21, 81% response rate). A total of 6 postoperative infections after ACDF were identified for a mean rate of 0.07% (range 0% to 0.39%). The mean age of patients identified was 57.5 (SD = 11.6, 66.7% female). The mean body mass index was 22.02. Of the total infections, half were smokers (n = 3). Two patients presented with myelopathy, and 3 patients presented with radiculopathic-type complaints. The mean length of stay was 4.7 days. All patients were treated aggressively with surgery for management of this complication, with improvement in all patients. There were no mortalities., Conclusion: The incidence of postoperative infection in ACDF is exceedingly low. The management has historically been urgent irrigation and debridement of the surgical site. However, due to the rarity of this occurrence, guidance for management is limited to retrospective series., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Tony Tannoury reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AO Spine during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Bruce C. Jobse reports grants from AOSpine North America during the conduct of the study; Sara E. Thompson reports grants from AOSpine North America during the conduct of the study; K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; George M. Ghobrial reports grants from AOSpine North America, during the conduct of the study; James S. Harrop reports grants from AOSpine North America, during the conduct of the study; personal fees from Depuy spine, personal fees from Tejin, Asterias, Bioventus, outside the submitted work; Rick C. Sasso reports grants from AOSpine North America, during the conduct of the study; personal fees from medtronic, grants from medtronic, grants from K2, outside the submitted work; Chadi A. Tannoury reports grants from AOSpine North America, during the conduct of the study; Zachary A. Smith reports grants from AOSpine North America, during the conduct of the study; Paul M. Arnold reports grants from AOSpine North America, during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Anthony F. De Giacomo reports grants from AOSpine North America, during the conduct of the study; Ra'Kerry K. Rahman reports grants from AOSpine North America, during the conduct of the study; in addition, Dr. Rahman has a patent Deformity System & Pedicle Screws pending.

Study Design: A multicenter, retrospective case series., Objective: In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication., Methods: A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center., Results: A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%)., Conclusions: This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Jeremy C. Peterson reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Robert A. Hart reports grants from AOSpine North America during the conduct of the study, other from CSRS, other from ISSLS, other from ISSG Exec Board, personal fees from Depuy Synthes, personal fees from Globus, personal fees from Medtronic, other from Evans, Craven & Lackie, other from Benson, Bertoldo, Baker, & Carter, personal fees from Seaspine, personal fees from Depuy Synthes, other from Spine Connect, personal fees from Depuy Synthes, outside the submitted work; Alan S. Hilibrand reports grants from AOSpine North America during the conduct of the study, other from Amedica, Vertiflex, Benvenue, Lifespine, Paradigm Spine, PSD, Spinal Ventures, outside the submitted work, and in addition, Dr. Hilibrand has a patent Aesculap, Amedica, Biomet, Stryker, Alphatec, with royalties paid; Tony Tannoury reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AO Spine during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Bradford L. Currier reports grants from AOSpine North America during the conduct of the study, personal fees from DePuy Spine, personal fees from Stryker Spine, personal fees from Zimmer Spine, other from Zimmer Spine, other from Tenex, other from Spinology, other from LSRS, other from AOSNA, outside the submitted work; Jeremy L. Fogelson reports grants from AOSpine North America during the conduct of the study and Previous Consultant for one day to Depuy-Synthes March 2014; Bruce C. Jobse reports grants from AOSpine North America during the conduct of the study; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark Consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plaintiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; Ra’Kerry K. Rahman reports grants from AOSpine North America during the conduct of the study; in addition, Dr. Rahman has a patent Deformity System & Pedicle Screws pending. Chadi A. Tannoury reports grants from AOSpine North America during the conduct of the study; Anthony F. De Giacomo Dr. De Giacomo reports grants from AOSpine North America during the conduct of the study.

Study Design: A multicenter, retrospective cohort study., Objective: To evaluate clinical outcomes in patients with reintubation after anterior cervical spine surgery., Methods: A total of 8887 patients undergoing anterior cervical spine surgery were enrolled in the AOSpine North America Rare Complications of Cervical Spine Surgery study. Patients with or without complications after surgery were included. Demographic and surgical information were collected for patients with reintubation. Patients were evaluated using a variety of assessment tools, including the modified Japanese Orthopedic Association scale, Nurick score, Neck Disability Index, and Short Form-36 Health Survey., Results: Nine cases of postoperative reintubation were identified. The total prevalence of this complication was 0.10% and ranged from 0% to 0.59% across participating institutions. The time to development of airway symptoms after surgery was within 24 hours in 6 patients and between 5 and 7 days in 3 patients. Although 8 patients recovered, 1 patient died. At final follow-up, patients with reintubation did not exhibit significant and meaningful improvements in pain, functional status, or quality of life., Conclusions: Although the prevalence of reintubation was very low, this complication was associated with adverse clinical outcomes. Clinicians should identify their high-risk patients and carefully observe them for up to 2 weeks after surgery., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Narihito Nagoshi reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Hiroaki Nakashima reports grants from AOSpine North America during the conduct of the study; Lindsay Tetreault reports grants from AOSpine North America during the conduct of the study; Jeffrey L. Gum reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, Alphatec, Stryker, LifeSpine, Acuity, Pacira, PAKmed, Gerson Lehrman Group, personal fees from OREF, AOSpine, personal fees from Acuity, other from Medtronic, personal fees from MiMedx, Pacira Pharmaceuticals, Alphatec, grants from Fischer Owen Fund, nonfinancial support from American Journal of Orthopaedics, nonfinancial support from American Journal of Orthopaedics, The Spine Journal, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Chadi A. Tannoury reports grants from AOSpine North America during the conduct of the study; Tony Tannoury reports grants from AOSpine North America during the conduct of the study; Vincent C. Traynelis reports grants from AOSpine North America during the conduct of the study, grants from National Institutes of Health, outside the submitted work, and Consultant for Medtronic Royalties from Medtronic Institutional Fellowship Support from Globus; Thomas E. Mroz reports other from AOSpine, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Ziya L. Gokaslan reports grants from AOSpine North America during the conduct of the study, grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Mohamad Bydon reports grants from AOSpine North America during the conduct of the study; Bruce C. Jobse reports grants from AOSpine North America during the conduct of the study; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Anthony F. De Giacomo reports grants from AOSpine North America during the conduct of the study.

Study Design: Multicenter retrospective case series and review of the literature., Objective: To determine the rate of esophageal perforations following anterior cervical spine surgery., Methods: As part of an AOSpine series on rare complications, a retrospective cohort study was conducted among 21 high-volume surgical centers to identify esophageal perforations following anterior cervical spine surgery. Staff at each center abstracted data from patients' charts and created case report forms for each event identified. Case report forms were then sent to the AOSpine North America Clinical Research Network Methodological Core for data processing and analysis., Results: The records of 9591 patients who underwent anterior cervical spine surgery were reviewed. Two (0.02%) were found to have esophageal perforations following anterior cervical spine surgery. Both cases were detected and treated in the acute postoperative period. One patient was successfully treated with primary repair and debridement. One patient underwent multiple debridement attempts and expired., Conclusions: Esophageal perforation following anterior cervical spine surgery is a relatively rare occurrence. Prompt recognition and treatment of these injuries is critical to minimizing morbidity and mortality., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Stuart H. Hershman reports grants from AOSpine North America during the conduct of the study; William A. Kunkle reports grants from AOSpine North America during the conduct of the study; Michael P. Kelly reports grants from AOSpine North America during the conduct of the study; Wilson Z. Ray reports grants from NIH/NINDs, grants from Department of Defense, grants from DARPA, other from Depuy/Synthes, other from Ulrich, other from Harvest Technologies, outside the submitted work; David B. Bumpass reports grants from AOSpine North America during the conduct of the study, grants from North American Spine Society, personal fees from Doximity, personal fees from Gerson Lehrman Group, outside the submitted work; Jeffrey L. Gum reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, Alphatec, Stryker, LifeSpine, Acuity, Pacira, PAKmed, Gerson Lehrman Group, personal fees from OREF, AOSpine, personal fees from Acuity, other from Medtronic, personal fees from MiMedx, Pacira Pharmaceuticals, Alphatec, grants from Fischer Owen Fund, nonfinancial support from American Journal of Orthopaedics, nonfinancial support from American Journal of Orthopaedics, The Spine Journal, outside the submitted work; Colleen M. Peters reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Bradford L. Currier reports grants from AOSpine North America during the conduct of the study, personal fees from DePuy Spine, personal fees from Stryker Spine, personal fees from Zimmer Spine, other from Zimmer Spine, other from Tenex, other from Spinology, other from LSRS, other from AOSNA, outside the submitted work; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; Justin S. Smith reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Nuvasive, personal fees from Cerapedics, personal fees from K2M, personal fees and other from DePuy, personal fees from Medtronic, outside the submitted work; Christopher Shaffrey reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Medtronic, from Nuvasive, personal fees from K2M, personal fees from Stryker, outside the submitted work; and Editorial Board Spine, Spinal Deformity and Neurosurgery; Sara E. Thompson reports grants from AOSpine North America during the conduct of the study; Jeffrey C. Wang reports grants from AOSpine North America during the conduct of the study; Elizabeth L. Lord reports grants from AOSpine North America during the conduct of the study; Zorica Buser reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AOSpine during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plaintiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Jacob M. Buchowski reports grants from AOSpine North America during the conduct of the study; personal fees from Advance Medical, personal fees from DePuy, personal fees from CoreLink, Inc., personal fees from Globus Medical, Inc., personal fees from K2M, Inc., personal fees from Medtronic, Inc., personal fees from Stryker, Inc., personal fees from Broadwater/Vertical Health, personal fees from DePuy Synthes, personal fees from Globus Medical, Inc., personal fees from Orthofix, personal fees from Stryker, Inc., personal fees from Wolters Kluwer Health, Inc., personal fees from Globus Medical, Inc., outside the submitted work; and AO Foundation (parent organization to AO Spine). AO FOUNDATION is a non for profit organization. “Other”, “Teaching”, “Not for Profit Organization” Weerasak Singhatanadgige reports grants from AOSpine North America during the conduct of the study; Jin Young Kim Dr. Kim reports grants from AOSpine North America, during the conduct of the study; Zachary A. Smith Dr. Smith reports grants from AOSpine North America, during the conduct of the study; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; Ra'Kerry K. Rahman reports grants from AOSpine North America during the conduct of the study; in addition, Dr. Rahman has a patent Deformity System & Pedicle Screws pending; Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work.

Study Design: This study was a retrospective, multicenter cohort study., Objectives: Rare complications of cervical spine surgery are inherently difficult to investigate. Pseudomeningocoele (PMC), an abnormal collection of cerebrospinal fluid that communicates with the subarachnoid space, is one such complication. In order to evaluate and better understand the incidence, presentation, treatment, and outcome of PMC following cervical spine surgery, we conducted a multicenter study to pool our collective experience., Methods: This study was a retrospective, multicenter cohort study of patients who underwent cervical spine surgery at any level(s) from C2 to C7, inclusive; were over 18 years of age; and experienced a postoperative PMC., Results: Thirteen patients (0.08%) developed a postoperative PMC, 6 (46.2%) of whom were female. They had an average age of 48.2 years and stayed in hospital a mean of 11.2 days. Three patients were current smokers, 3 previous smokers, 5 had never smoked, and 2 had unknown smoking status. The majority, 10 (76.9%), were associated with posterior surgery, whereas 3 (23.1%) occurred after an anterior procedure. Myelopathy was the most common indication for operations that were complicated by PMC (46%). Seven patients (53%) required a surgical procedure to address the PMC, whereas the remaining 6 were treated conservatively. All PMCs ultimately resolved or were successfully treated with no residual effects., Conclusions: PMC is a rare complication of cervical surgery with an incidence of less than 0.1%. They prolong hospital stay. PMCs occurred more frequently in association with posterior approaches. Approximately half of PMCs required surgery and all ultimately resolved without residual neurologic or other long-term effects., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Tamir Ailon reports grants from AOSpine North America, during the conduct of the study; Justin S. Smith reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Nuvasive, personal fees from Cerapedics, personal fees from K2M, personal fees and other from DePuy, personal fees from Medtronic, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; David E. Fish reports grants from AOSpine North America during the conduct of the study; Jeffrey C. Wang reports grants from AOSpine North America during the conduct of the study; Alan S. Hilibrand reports grants from AOSpine North America during the conduct of the study, other from Amedica, Vertiflex, Benvenue, Lifespine, Paradigm Spine, PSD, Spinal Ventures, outside the submitted work, and in addition, Dr. Hilibrand has a patent Aesculap, Amedica, Biomet, Stryker, Alphatec, with royalties paid; Praveen V. Mummaneni reports grants from AOSpine North America during the conduct of the study, other from Depuy Spine, grants and other from AOSpine, other from Globus, other from Springer Publishers, other from Thieme Publishers, other from Taylor and Francis Publishers, other from Spincity/ISD, outside the submitted work; Dean Chou reports grants from AOSpine North America during the conduct of the study, other from Globus, other from Medtronic, other from Orthofix, outside the submitted work; Vincent C. Traynelis reports grants from AOSpine North America during the conduct of the study, and Medtronic - Royalties and Consultant Globus - Institutional Fellowship Support; Thomas E. Mroz reports other from AO Spine, grants from AOSpine North America during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Zorica Buser reports grants from AOSpine North America during the conduct of the study; Elizabeth L. Lord reports grants from AOSpine North America during the conduct of the study; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; Arjun S. Sebastian reports grants from AOSpine North America during the conduct of the study; Khoi D. Than reports grants from AOSpine North America during the conduct of the study; Michael P. Steinmetz reports grants from AOSpine North America during the conduct of the study; Gabriel A. Smith reports grants from AOSpine North America during the conduct of the study; Jonathan Pace reports grants from AOSpine North America during the conduct of the study; K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; and Christopher Shaffrey reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Medtronic, from Nuvasive, personal fees from K2M, personal fees from Stryker, outside the submitted work, and Editorial Board Spine, Spinal Deformity and Neurosurgery; Hani R. Malone reports grants from AOSpine North America during the conduct of the study; Adam S. Kanter reports grants from AOSpine North America during the conduct of the study; Samuel K. Cho reports grants from AOSpine North America during the conduct of the study; grants from OREF, personal fees from Stryker, personal fees from Medtronic, personal fees from DePuy Synthes, outside the submitted work; Ra'Kerry K. Rahman reports grants from AOSpine North America during the conduct of the study; in addition, Dr. Rahman has a patent Deformity System & Pedicle Screws pending. Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work.

Study Design: A multicenter retrospective case series was compiled involving 21 medical institutions. Inclusion criteria included patients who underwent cervical spine surgery between 2005 and 2011 and who sustained a vertebral artery injury (VAI)., Objective: To report the frequency, risk factors, outcomes, and management goals of VAI in patients who have undergone cervical spine surgery., Methods: Patients were evaluated on the basis of condition-specific functional status using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) score, the Nurick scale, and the 36-Item Short-Form Health Survey (SF-36)., Results: VAIs were identified in a total of 14 of 16 582 patients screened (8.4 per 10 000). The mean age of patients with VAI was 59 years (±10) with a female predominance (78.6%). Patient diagnoses included myelopathy, radiculopathy, cervical instability, and metastatic disease. VAI was associated with substantial blood loss (770 mL), although only 3 cases required transfusion. Of the 14 cases, 7 occurred with an anterior-only approach, 3 cases with posterior-only approach, and 4 during circumferential approach. Fifty percent of cases of VAI with available preoperative imaging revealed anomalous vessel anatomy during postoperative review. Average length of hospital stay was 10 days (±8). Notably, 13 of the 14 (92.86%) cases resolved without residual deficits. Compared to preoperative baseline NDI, Nurick, mJOA, and SF-36 scores for these patients, there were no observed changes after surgery ( P = .20-.94)., Conclusions: Vertebral artery injuries are potentially catastrophic complications that can be sustained from anterior or posterior cervical spine approaches. The data from this study suggest that with proper steps to ensure hemostasis, patients recover function at a high rate and do not exhibit residual deficits., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Wellington K. Hsu reports grants from AOSpine North America, during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Abhishek Kannan, reports grants from AOSpine North America, during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America, during the conduct of the study; Vincent C. Traynelis reports grants from AOSpine North America during the conduct of the study, Medtronic - Royalties, Consultant Globus - Institutional Fellowship Support; Ziya L. Gokaslan reports grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Alan S. Hilibrand reports grants from AOSpine North America during the conduct of the study, other from Amedica, Vertiflex, Benvenue, Lifespine, Paradigm Spine, PSD, Spinal Ventures, outside the submitted work, and in addition, Dr. Hilibrand has a patent Aesculap, Amedica, Biomet, Stryker, Alphatec, with royalties paid; Thomas E. Mroz reports other from AOSpine, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Eric M. Massicotte reports grants from AOSpine North America during the conduct of the study, grants from Medtronic, Depuy-Synthes Spine Canada, personal fees from Watermark Consulting, grants from AOSpine North America, nonfinancial support from AOSpine North America, outside the submitted work; Wilson Z. Ray reports grants from NIH/NINDs, grants from Department of Defense, grants from DARPA, other from Depuy/Synthes, other from Ulrich, other from Harvest Technologies, outside the submitted work; Michael P. Steinmetz reports grants from AOSpine North America during the conduct of the study; Gabriel A. Smith reports grants from AOSpine North America during the conduct of the study; Jonathan Pace reports grants from AOSpine North America during the conduct of the study; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; Jeffrey C. Wang reports grants from AOSpine North America during the conduct of the study; Elizabeth L. Lord reports grants from AOSpine North America during the conduct of the study; Zorica Buser reports grants from AOSpine North America during the conduct of the study; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Paul M. Arnold reports grants from AOSpine North America, during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work; Mohamad Bydon reports grants from AOSpine North America during the conduct of the study; Mark Corriveau reports grants from AOSNA during the conduct of the study; Harry T. Mai reports grants from AOSpine North America during the conduct of the study; Ahmad Nassr reports grants from AOSNA from null, during the conduct of the study; Sungho Lee reports grants from AOSpine North America, during the conduct of the study.

Study Design: A multicenter retrospective case series., Objective: Horner's syndrome is a known complication of anterior cervical spinal surgery, but it is rarely encountered in clinical practice. To better understand the incidence, risks, and neurologic outcomes associated with Horner's syndrome, a multicenter study was performed to review a large collective experience with this rare complication., Methods: We conducted a retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records for 17 625 patients who received subaxial cervical spine surgery from 2005 to 2011 were reviewed to identify occurrence of 21 predefined treatment complications. Descriptive statistics were provided for baseline patient characteristics. Paired t test was used to analyze changes in clinical outcomes at follow-up compared to preoperative status., Results: In total, 8887 patients who underwent anterior cervical spine surgery at the participating institutions were screened. Postoperative Horner's syndrome was identified in 5 (0.06%) patients. All patients experienced the complication following anterior cervical discectomy and fusion. The sympathetic trunk appeared to be more vulnerable when operating on midcervical levels (C5, C6), and most patients experienced at least a partial recovery without further treatment., Conclusions: This collective experience suggests that Horner's syndrome is an exceedingly rare complication following anterior cervical spine surgery. Injury to the sympathetic trunk may be limited by maintaining a midline surgical trajectory when possible, and performing careful dissection and retraction of the longus colli muscle when lateral exposure is necessary, especially at caudal cervical levels., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Vincent C. Traynelis reports grants from AOSpine North America during the conduct of the study, and Medtronic - Royalties, Consultant Globus - Institutional Fellowship Support; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Sheeraz A. Qureshi reports grants from AOSpine North America during the conduct of the study, and is a consultant and receives royalties from Stryker Spine, Biomet Spine, and RTI; Evan O. Baird reports grants from AOSpine North America during the conduct of the study; Robert E. Isaacs reports grants from AOSpine North America during the conduct of the study, grants and personal fees from NuVasive, Inc., personal fees from Association for Collaborative Spine research, outside the submitted work; Galina Polevaya reports grants from AOSpine North America during the conduct of the study; Justin S. Smith reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Nuvasive, personal fees from Cerapedics, personal fees from K2M, personal fees and other from DePuy, personal fees from Medtronic, outside the submitted work; Christopher Shaffrey reports grants from AOSpine North America during the conduct of the study, personal fees from Biomet, personal fees from Medtronic, from Nuvasive, personal fees from K2M, personal fees from Stryker, outside the submitted work, and Editorial Board Spine, Spinal Deformity and Neurosurgery; P. Justin Tortolani reports grants from AOSpine North America during the conduct of the study, other from Globus Medical, grants from Spineology, other from Innovasis, outside the submitted work, and in addition, Dr. Tortolani has a patent Globus with royalties paid; D. Alex Stroh reports grants from AOSpine North America during the conduct of the study; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; Thomas E. Mroz reports other from AOSpine, grants from AOSpine North America, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff , grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Hani R. Malone reports grants from AOSpine North America during the conduct of the study; Adam S. Kanter reports grants from AOSpine North America during the conduct of the study; Samuel K. Cho reports grants from AOSpine North America during the conduct of the study; grants from OREF, personal fees from Stryker, personal fees from Medtronic, personal fees from DePuy Synthes, outside the submitted work; Ra'Kerry K. Rahman reports grants from AOSpine North America during the conduct of the study; in addition, Dr. Rahman has a patent Deformity System & Pedicle Screws pending. Paul M. Arnold reports grants from AOSpine North America during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work.

Study Design: Multicenter retrospective study., Objectives: To investigate the risk of symptomatic recurrent laryngeal nerve palsy (RLNP) following cervical spine surgery, to examine risk factors for its development, and to report its treatment and outcomes., Methods: A multicenter study from 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was performed. Each center screened for rare complications following cervical spine surgery, including RLNP. Patients were included if they underwent cervical spine surgery (levels from C2 to C7) between January 1, 2005 and December 31, 2011. Data were analyzed with regard to complication treatment and outcome. Cases were compared to a control group from the AOSpine CSM and CSM-I studies., Results: Three centers reported 19 cases of RLNP from a cohort of 1345 patients. The reported incidence of RLNP ranged from 0.6% to 2.9% between these 3 centers. Fifteen patients (79%) in the RLNP group were approached from the left side. Ten patients (52.6%) required treatment for RLNP-6 required medical therapy (steroids), 1 interventional treatment (injection laryngoplasty), and 3 conservative therapy (speech therapy). When examining outcomes, 73.7% (14/19) of cases resolved completely, 15.8% (3/19) resolved with residual effects, and in 10.5% (2/19) of cases this could not be determined., Conclusions: In this multicenter study examining rare complications following cervical spine surgery, the risk of RLNP after cervical spine surgery ranged from 0.6% to 2.9% between centers. Though rare, it was found that 16% of patients may experience partial resolution with residual effects, and 74% resolve completely., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Ziya L. Gokaslan reports grants from AOSpine North America, personal fees from AO Foundation, grants from AOSpine, outside the submitted work; Zachary A. Smith reports grants from AOSpine North America during the conduct of the study; Wellington K. Hsu reports grants from AOSpine North America during the conduct of the study, personal fees from Medtronic, personal fees from Stryker, personal fees from Bacterin, personal fees from Graftys, personal fees from Ceramtec, personal fees from Relievant, personal fees from Bioventus, personal fees from Globus, personal fees from SpineSmith, outside the submitted work; Sheeraz A. Qureshi reports grants from AOSpine North America during the conduct of the study, and is a consultant and receive royalties from Stryker Spine, Biomet Spine, and RTI; Thomas E. Mroz reports other from AOSpine, during the conduct of the study, personal fees from Stryker, personal fees from Ceramtec, other from Pearl Diver, outside the submitted work; Michael Fehlings reports grants from AOSpine North America during the conduct of the study; and K. Daniel Riew reports personal fees from AOSpine International, other from Global Spine Journal, other from Spine Journal, other from Neurosurgery, personal fees from Multiple Entities for defense, plantiff, grants from AOSpine, grants from Cerapedics, grants from Medtronic, personal fees from AOSpine, personal fees from NASS, personal fees from Biomet, personal fees from Medtronic, nonfinancial support from Broadwater, outside the submitted work; Mohamad Bydon reports grants from AOSpine North America during the conduct of the study; Rafael De la Garza-Ramos reports grants from AOSpine North America during the conduct of the study; Samuel K. Cho Dr. Cho reports grants from AOSpine North America during the conduct of the study; grants from OREF, personal fees from Stryker, personal fees from Medtronic, personal fees from DePuy Synthes, outside the submitted work; Evan O. Baird reports grants from AOSpine North America during the conduct of the study; Paul M. Arnold Paul M. Arnold reports grants from AOSpine North America, during the conduct of the study; other from Z-Plasty, other from Medtronic Sofamore Danek, other from Stryker Spine, other from FzioMed, other from AOSpine North America, other from Life Spine, other from Integra Life, other from Spine Wave, other from MIEMS, other from Cerapedics, other from AOSpine North America, outside the submitted work.

Study Design: A retrospective, multivariate analyses of a prospectively collected multicenter database., Objective: The aim of this study was to evaluate the risk factors for postoperative airway complications following single- and multilevel anterior cervical discectomy and fusion (ACDF)., Summary of Background Data: Airway compromise following ACDF may result in catastrophic outcome. However, its predictors have not been identified by a multi-institutional study., Methods: Patients who underwent ACDF between 2011 and 2013 were selected from the American College of Surgeons National Surgical Quality Improvement Program database. Multiple logistic regression analysis was performed to identify the risk factors for airway compromise following ACDF., Results: Twelve thousand one hundred eighty-five patients were analyzed in this study. Our multivariate analysis identified older age, male gender, dependent functional status, chronic obstructive pulmonary disease, bleeding disorder, American Society of Anesthesiology class >2, Wound Class >2, and prolonged operative durations as significant predictors of postoperative airway compromise following ACDF. Surprisingly, multilevel and corpectomy procedures were not significant risk factors for airway complication following ACDF., Conclusion: We identified significant risk factors for airway compromise following ACDF procedures. While ACDF is considered a safe procedure, postoperative airway complication can lead to disastrous outcome. Continued efforts to elucidate preoperative risk factors and subsequent optimization are warranted to improve outcomes in ACDF., Level of Evidence: 3.

Background Context: Higher American Society of Anesthesiologists (ASA) classification is a known predictor of postoperative complication in diverse surgical settings. However, its predictive value is not established in single-level elective anterior cervical discectomy and fusion (SLE-ACDF)., Purpose: This study aimed to evaluate the predictive value of ASA classification system on 30-day morbidity following SLE-ACDF., Design/setting: Patients who underwent SLE-ACDF between 2011 and 2013 were selected from the American College of Surgeons National Surgical Quality Improvement Program database., Patient Sample: A total of 6,148 patients were selected from the 2011-2013 American College of Surgeons National Surgical Quality Improvement Program database., Outcome Measures: All outcomes are self-report measures as tracked by dedicated clinical reviewers via prospective review of inpatient charts, outpatient clinic visits, and direct contact with the surgical team., Methods: Propensity score matching and multiple logistic regression analyses were performed to evaluate ASA classification as 30-day morbidity predictor. This study has no financial conflict and has no potential conflict of interest to disclose., Results: A total of 6,148 patients were analyzed in this study. Patients in the ASA >II cohort had higher incidence of comorbidities and postoperative complications (overall complication, pneumonia, unplanned intubation, ventilator dependent >48 hours, cerebrovascular accident or stroke, catastrophic outcome, and airway complication). Propensity score matching yielded 1,628 pairs of well-matched patients. Multivariable analyses with the propensity score matched dataset revealed the following associations between ASA class >II and 30-day outcomes: any complication (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.48-1.41), pneumonia (OR 1.22, 95% CI 0.33-4.56), unplanned intubation (OR 1.49, 95% CI 0.41-5.36), ventilator >48 hours (OR 5.92, 95% CI 0.69-50.96), catastrophic outcome (OR 1.02, 95% CI 0.39-2.71), and airway complication (OR 2.21, 95% CI 0.67-7.29)., Conclusions: Although we did not detect associations between ASA class >II and adverse 30-day outcomes following SLE-ACDF, imprecision of estimates precludes definitive inferences. Although ASA classification allows simple assessment of patients' physiological status, their overall perioperativerisk factors need to be considered collectively for adequate optimization and improved outcomes in SLE-ACDF., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Competing Interests: There are no conflicts of interest.