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Implant related infection following spine surgery is a devastating complication for patients and can potentially lead to significant neurological compromise, disability, morbidity, and even mortality. This paper provides an overview of the existing animal models of postoperative spine infection and highlights the strengths and weaknesses of each model. In addition, there is discussion regarding potential modifications to these animal models to better evaluate preventative and treatment strategies for this challenging complication. Current models are effective in simulating surgical procedures but fail to evaluate infection longitudinally using multiple techniques. Potential future modifications to these models include using advanced imaging technologies to evaluate infection, use of bioluminescent bacterial species, and testing of novel treatment strategies against multiple bacterial strains. There is potential to establish a postoperative spine infection model using smaller animals, such as mice, as these would be a more cost-effective screening tool for potential therapeutic interventions.

Study Design: Retrospective chart review., Objective: The goal of this study is to examine the relationship between global alignment and proportion (GAP) score and postoperative orthoses with likelihood of developing proximal junctional kyphosis (PJK)., Methods: Patients who underwent thoracic or lumbar fusions of ≥4 levels for adult spinal deformity (ASD) with 1-year post-operative alignment x-rays were included. Chart review was conducted to determine spinopelvic alignment parameters, PJK, and reoperation., Results: A total of 81 patients were included; baseline and 1-year postoperative alignment did not differ between patients with and without PJK. There was no PJK in 53.1%, 29.6% had PJK from 10-20°, and 17.3% had severe PJK over 20° (sPJK). At baseline, 80% of patients had severely disproportioned GAP, 13.75% moderate, 6.25% proportioned. GAP improved across the population, but improved GAP was not associated with sPJK. Greater correction of the upper instrumented vertebra to pelvic angle (UIV-PA) was associated with a larger PJK angle (PJKA) change (R = -0.28) as was the 1 year T1-upper instrumented vertebra (T1-UIV) angle (R = 0.30), both P < .05. GAP change was not correlated with PJKA change. Postoperative orthoses were used in 46% of patients and did not impact sPJK., Conclusions: There was no correlation between PJK and GAP or change in GAP. Greater correction of UIV-PA and larger postop T1-UIV was associated with greater PJKA change; suggesting that the greater alignment correction led to greater likelihood of failure. Postoperative orthoses had no impact on PJK.

Study Design: A retrospective, case-control study., Objective: We aim to build a risk calculator predicting major perioperative complications after anterior cervical fusion. In addition, we aim to externally validate this calculator with an institutional cohort of patients who underwent anterior cervical discectomy and fusion (ACDF)., Summary of Background Data: The average age and proportion of patients with at least one comorbidity undergoing ACDF have increased in recent years. Given the increased morbidity and cost associated with perioperative complications and unplanned readmission, accurate risk stratification of patients undergoing ACDF is of great clinical utility., Methods: This is a retrospective cohort study of adults who underwent anterior cervical fusion at any nonfederal California hospital between 2015 and 2017. The primary outcome was major perioperative complication or 30-day readmission. We built standard and ensemble machine learning models for risk prediction, assessing discrimination, and calibration. The best-performing model was validated on an external cohort comprised of consecutive adult patients who underwent ACDF at our institution between 2013 and 2020., Results: A total of 23,184 patients were included in this study; there were 1886 cases of major complication or readmissions. The ensemble model was well calibrated and demonstrated an area under the receiver operating characteristic curve of 0.728. The variables most important for the ensemble model include male sex, medical comorbidities, history of complications, and teaching hospital status. The ensemble model was evaluated on the validation cohort (n=260) with an area under the receiver operating characteristic curve of 0.802. The ensemble algorithm was used to build a web-based risk calculator., Conclusion: We report derivation and external validation of an ensemble algorithm for prediction of major perioperative complications and 30-day readmission after anterior cervical fusion. This model has excellent discrimination and is well calibrated when tested on a contemporaneous external cohort of ACDF cases., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Achieving fusion in spine surgery can be challenging because of patient factors such as smoking and diabetes. The consequences of pseudarthrosis can be severe, including pain, instability, and additional surgery. Autologous iliac crest bone graft is the historical standard for augmenting spine fusion, providing high rates of fusion throughout the cervical, thoracic, and lumbar spine. Harvest of autologous iliac crest bone can be associated with comorbidities and this has led to development of alternative biologic materials to enhance spine fusion. Substitutes include various forms of allograft products including decellularized allograft; demineralized bone matrix; synthetic materials including bioactive glass; and autologous and allograft mesenchymal stem cells. Bone morphogenetic proteins can be efficacious for fusion but have significant risks and are not suitable for all spine procedures. There is a wide variety of utilization of biologics for spine fusion that are influenced by spinal region, surgeon preference, surgical training, health system formulary, and cost.

Background: C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy., Methods: We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model., Results: A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age., Conclusions: We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: Posterior cervical fusion is associated with increased rates of complications and readmission when compared to anterior fusion. Machine learning (ML) models for risk stratification of patients undergoing posterior cervical fusion remain limited. We aim to develop a novel ensemble ML algorithm for prediction of major perioperative complications and readmission after posterior cervical fusion and identify factors important to model performance., Methods: This is a retrospective cohort study of adults who underwent posterior cervical fusion at non-federal California hospitals between 2015 and 2017. The primary outcome was readmission or major complication. We developed an ensemble model predicting complication risk using an automated ML framework. We compared performance with standard ML models and logistic regression (LR), ranking contribution of included variables to model performance., Results: Of the included 6822 patients, 18.8% suffered a major complication or readmission. The ensemble model demonstrated slightly superior predictive performance compared to LR and standard ML models. The most important features to performance include sex, malignancy, pneumonia, stroke, and teaching hospital status. Seven of the ten most important features for the ensemble model were markedly less important for LR., Conclusion: We report an ensemble ML model for prediction of major complications and readmission after posterior cervical fusion with a modest risk prediction advantage compared to LR and benchmark ML models. Notably, the features most important to the ensemble are markedly different from those for LR, suggesting that advanced ML methods may identify novel prognostic factors for adverse outcomes after posterior cervical fusion., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Ogilvie syndrome (OS) is a rare but serious condition seen in the postoperative period. This was an epidemiologic study using data from the National Inpatient Sample from 2005 to 2014 to look at incidence, risk factors, and outcomes associated with OS after primary spine fusion., Methods: International Classification of Diseases, Ninth Revision codes were used to identify patients who underwent spine fusion surgery. Patients were separated into 2 cohorts based on the diagnosis of OS. Outcome measures and risk factors for cohorts were analyzed using multivariate logistic regression and compared., Results: Over the 10-year study period, 3,884,395 patients underwent primary spine fusion surgery. Among these, 0.04% developed OS during the index hospitalization. The greatest incidence seen in primary fusion involved the thoracic spine (0.15%). OS was more common after spine fusion for spine deformity (P < 0.001). Patients with OS were more likely to be men (P < 0.001), older (P < 0.0001), and have more comorbidities (P < 0.0001). Patients with OS were more likely to require postoperative blood transfusions (odds ratio [OR], 3.39; 95% confidence interval [CI], 2.51-4.59; P < 0.001) and sustain any complication (OR, 4.20; 95% CI, 3.17-5.57; P < 0.001). Patients with OS had a longer length of stay (15.7 vs. 3.9 days; P < 0.001) and increased average hospitalization cost ($63,037.03 vs. $26,792.19; P < 0.001). The development of OS was associated with fluid electrolyte disorder (OR, 4.06; 95% CI, 2.99-5.51; P < 0.001)., Conclusions: OS is a rare but serious complication of primary spine fusion surgery. Identifying the specific risk factors, symptoms, and potential complications related to OS is critical to aid in decreasing the significant morbidity associated with its development., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background Context: Computer-assisted navigation (CAN) has emerged in spine surgery as an approach to improve patient outcomes. While there is substantial evidence demonstrating improved pedicle screw accuracy in CAN as compared to conventional spinal fusion (CONV), there is limited data regarding clinical outcomes and utilization trends in the United States., Purpose: The purpose of this study was to determine the utilization rates of CAN in the United States, identify patient and hospital trends associated with both techniques, and to compare their results., Study Design: Retrospective review of national database., Patient Sample: Nationwide Inpatient Sample (NIS), United States national database., Outcome Measures: CAN utilization, mortality, medical complications, neurologic complications, discharge destination, length of hospital stay, cost of hospital stay., Methods: The NIS database was queried to identify patients undergoing spinal fusion with CAN or CONV. CAN and CONV utilization were tracked by year and anatomic location (cervical, thoracic, lumbar/lumbosacral). Patient demographics, hospital characteristics, index length of stay (LOS), and cost of stay (COS) were compared between the cohorts. After multivariate adjustment, index hospitalization clinical outcomes were compared., Results: A total of 4,275,413 patients underwent spinal fusion surgery during the study period (2004 to 2014). CONV was performed in 98.4% (4,208,068) of cases and CAN was performed in 1.6% (67,345) of cases. The utilization rate of CAN increased from 0.04% in 2004 to 3.3% in 2014. Overall, CAN was performed most commonly in the lumbar/lumbosacral region (70.4%) compared to the cervical (20.4%) or thoracic (9.2%) regions. When normalized to region-specific rates of fusion with any technique, the proportional utilization of CAN was highest in the thoracic spine (2.7%), followed by the lumbar/lumbosacral (2.2%) and cervical (0.9%) regions. CAN utilization was positively correlated with patient factors including increasing age and number of medical comorbidities. Multivariate adjusted clinical outcomes demonstrated that compared to CONV, CAN was associated with a statistically significant decreased risk of mortality (0.28% vs 0.31%, OR=0.67, 95% CI: 0.46-0.97, p=.035) and increased risk of blood transfusions (9.1% vs 6.7%, OR=1.19, 95% CI: 1.02-1.39, p=.032). However, there was no difference in risk of neurologic complications. CAN patients had an increased average LOS (4.44 days vs. 3.97 days, p<.0001) and average COS ($34,669.49 vs $26,784.62, p<.0001) compared to CONV patients., Conclusions: CAN utilization increased in the United States from 2004-2014. Use of CAN was proportionately higher in the thoracic and lumbar/lumbosacral regions and in older patients with more comorbidities. Given the continued trend towards increased CAN utilization, large-scale studies are needed to determine the impact of this technology on long-term clinical outcomes., (Published by Elsevier Inc.)

Background: Given the significant cost and morbidity of patients undergoing lumbar fusion, accurate preoperative risk-stratification would be of great utility. We aim to develop a machine learning model for prediction of major complications and readmission after lumbar fusion. We also aim to identify the factors most important to performance of each tested model., Methods: We identified 38,788 adult patients who underwent lumbar fusion at any California hospital between 2015 and 2017. The primary outcome was major perioperative complication or readmission within 30 days. We build logistic regression and advanced machine learning models: XGBoost, AdaBoost, Gradient Boosting, and Random Forest. Discrimination and calibration were assessed using area under the receiver operating characteristic curve and Brier score, respectively., Results: There were 4470 major complications (11.5%). The XGBoost algorithm demonstrates the highest discrimination of the machine learning models, outperforming regression. The variables most important to XGBoost performance include angina pectoris, metastatic cancer, teaching hospital status, history of concussion, comorbidity burden, and workers' compensation insurance. Teaching hospital status and concussion history were not found to be important for regression., Conclusions: We report a machine learning algorithm for prediction of major complications and readmission after lumbar fusion that outperforms logistic regression. Notably, the predictors most important for XGBoost differed from those for regression. The superior performance of XGBoost may be due to the ability of advanced machine learning methods to capture relationships between variables that regression is unable to detect. This tool may identify and address potentially modifiable risk factors, helping risk-stratify patients and decrease complication rates., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background Context: Metastatic spine disease (MSD) is becoming more prevalent as medical treatment for cancers advance and extend survival. More MSD patients are treated surgically to maintain neurological function, ambulation, and quality of life., Purpose: The purpose of this study was to use a large, nationally representative database to examine the trends, patient outcomes, and health-care resource utilization associated with surgical treatment of MSD., Design: This was an epidemiologic study using national administrative data from the Nationwide Readmissions Database (NRD)., Patient Sample: All patients in the NRD from 2010 to 2014 who underwent spinal surgery were included in the study., Outcome Measures: Mortality, blood transfusion, complications, length of stay, cost, and discharge location during index hospitalization as well as hospital readmission and revision surgery within 90-days of surgery were analyzed., Methods: International Classification of Diseases, Ninth Revision, (ICD-9) codes was used to identify patients of interest within the NRD from 2010 to 2014. Patients were separated into two cohorts - those with MSD and those without. Trends for surgical treatment of MSD were assessed and outcomes measures for both cohorts were analyzed and compared., Results: The number of surgical treatments for MSD increased from 6,007 in 2010 to 7,032 in 2014 (p-trend<.0001) which represented a 17.1% increase. During index hospitalization, MSD patients had an increased risk of mortality (odds ratio [OR]=3.22, 95% confidence interval [CI]: 2.85-3.63, p<.0001), blood transfusion (OR=2.93, 95% CI: 2.66-3.23, p<.0001), any complication (OR=1.24, 95% CI: 1.18-1.31, p<.0001), and discharge to skilled nursing facility (OR=1.51, 95% CI:1.41-1.61, p<.0001). MSD patients had longer average length of stay (13.05 vs. 4.56 days, p<.0001) and cost ($49,421.75 vs. $26,190.37, p<.0001) during index hospitalization. Furthermore, MSD patients had an increased risk of hospital readmission (OR=2.82, 95% CI: 2.68-2.96, p<.0001), readmission for surgical site infection (OR=2.38, 95% CI: 2.20-2.58, p<.0001), and readmission with neurologic deficits (OR=1.62, 95% CI: 1.27-2.06, p<.0001) despite a decreased risk of revision fusion (OR=0.71, 95% CI: 0.53-0.96, p=.026)., Conclusions: The number of MSD patients who undergo surgical treatments is increasing. Not only do these patients have worse outcomes during index hospitalization, but they are also at an increased risk of hospital readmission for surgical site infection and neurologic complications. These findings stress the need for multidisciplinary perioperative treatment plans that mitigate risks and facilitate quick, effective recovery in these unique, at-risk patients., (Published by Elsevier Inc.)

Background: Intraoperative neuromonitoring (ION), such as motor-evoked potential (MEP), somatosensory evoked potentials (SSEP), and electromyography (EMG), is used to detect impending neurological injuries during spinal surgery. To date, little is known about the trends in the use of ION for scoliosis surgery in the United States., Methods: A retrospective review was performed using the PearlDiver Database to identify patients that had scoliosis surgery with and without ION from years 2005 to 2011. Demographic information (such as age, gender, region within the United States) and clinical information (such as type of ION and rates of neurological injury) were assessed., Results: There were 3618 patients who had scoliosis surgery during the study period. Intraoperative neuromonitoring was used in 1361 (37.6%) of these cases. The number of cases in which ION was used increased from 27% in 2005 to 46.9% in 2011 ( P < .0001). Multimodal ION was used more commonly than unimodal ION (64.6% versus 35.4%). The most commonly used modality was combined SSEP and EMG, while the least used modality was MEP only. Neurological injuries occurred in 1.8 and 2.0% of patients that had surgery with and without ION, respectively ( P = .561). Intraoperative neuromonitoring was used most commonly in patients <65 years of age and in the Northeastern part of the United States (age P = .006, region P < .0001)., Conclusions: The use of ION for scoliosis surgery gradually increased annually from 2005 to 2011. Age and regional differences were noted with neuromonitoring being most commonly used for scoliosis surgery in nonelderly patients and in the Northeastern part of the United States. No differences were noted in the risk of neurological injury in patients that had surgery with and without ION. Although the findings from this study may seem to suggest that ION may not influence the risk of neurologic injury, this result must be interpreted with caution as inherently riskier surgeries may utilize ION more, leading to an actual reduction in injuries more dramatic than observed in this study., Competing Interests: Disclosures and COI: No funds were received in support of this work. No relevant financial disclosures are associated with this work.

Fractures are common, with an incidence of 13.7 per 1000 adults annually. Systemic agents have been widely used for enhancing bone regeneration; however, the efficacy of these therapeutics for the management and prevention of fracture remains unclear. NEL-like protein 1 (NELL-1) is a potent pro-osteogenic cytokine that has been modified with polyethylene glycol (PEG)ylation [PEGylated NELL-1 (NELL-PEG)] to enhance its pharmacokinetics for systemic therapy. Our aim was to investigate the effects of systemic administration of NELL-PEG on fracture healing in mice and on overall bone properties in uninjured bones. Ten-week-old CD-1 mice were subjected to an open osteotomy of bilateral radii and treated with weekly injections of NELL-PEG or PEG phosphate-buffered saline as control. Systemic injection of NELL-PEG resulted in improved bone mineral density of the fracture site and accelerated callus union. After 4 weeks of treatment, mice treated with NELL-PEG exhibited substantially enhanced callus volume, callus mineralization, and biomechanical properties. NELL-PEG injection significantly augmented bone regeneration, as confirmed by high expression of bone turnover rate, bone formation rate, and mineral apposition rate. Consistently, the immunohistochemistry results also confirmed a high bone remodeling activity in the NELL-PEG-treated group. Our findings suggest that weekly injection of NELL-PEG may have the clinical potential to accelerate fracture union and enhance overall bone properties, which may help prevent subsequent fractures., (Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background: Intraoperative neuromonitoring (ION) such as motor-evoked potential (MEP), somatosensory evoked potentials (SSEP) and electromyography (EMG) are used to detect impending neurological injuries during spinal surgery. To date, little is known on the trends in the use of ION for scoliosis surgery in the United States., Methods: A retrospective review was performed using the PearlDiver Database to identify patients that had scoliosis surgery with and without ION from years 2005 to 2011. Demographic information (such as age, gender, region within the United States) and clinical information (such as type of ION and rates of neurological injury) were assessed., Results: There were 3618 patients who had scoliosis surgery during the study period. ION was used in 1361 (37.6%) of these cases. The number of cases in which ION was used increased from 27% in 2005 to 46.9% in 2011 (p < 0.0001). Multimodal ION was used more commonly than unimodal ION (64.6% vs. 35.4%). The most commonly used modality was combined SSEP and EMG while the least used modality was MEP only. Neurological injuries occurred in 1.8% and 2.0% of patients that had surgery with and without ION, respectively (p = 0.561). ION was used most commonly in patients < 65 years of age and in the Northeastern part of the United States (age; p = 0.006, region; p < 0.0001)., Conclusions: The use of ION for scoliosis surgery gradually increased annually from 2005 to 2011. Age and regional differences were noted with neuromonitoring being most commonly used for scoliosis surgery in non-elderly patients and in the Northeastern part of the United States. No differences were noted in the risk of neurological injury in patients that had surgery with and without ION. Although the findings from this study may seem to suggest that ION may not influence the risk of neurologic injury, this result must be interpreted with caution as inherently riskier surgeries may utilize ION more, leading to an actual reduction in injuries more dramatic than observed in this study.

Study Design: Retrospective cohort study among Medicare beneficiaries who underwent posterior lumbar interbody fusion (PLIF) surgery., Objective: To identify the complication rates associated with the use of bone morphogenetic protein 2 (BMP2) in PLIF. Human BMP2 is commonly used in the "off-label" manner for various types of spine fusion procedures, including PLIF. However, recent studies have reported potential complications associated with the recombinant human BMP2 (rhBMP2) use in the posterior approach., Methods: Medicare records within the PearlDiver database were queried for patients undergoing PLIF procedure with and without rhBMP2 between 2005 and 2010. We evaluated complications within 1 year postoperatively. Chi-square was used to compare the complication rates between the 2 groups., Results: A total of 8609 patients underwent PLIF procedure with or without rhBMP2. Individual complication rates in the rhBMP2 group ranged from 0.45% to 7.68% compared with 0.65% to 10.99 in the non-rhBMP2 group. Complication rates for cardiac, pulmonary, lumbosacral neuritis, infection, wound, and urinary tract (include acute kidney failure and post-operative complications) were significantly lower in the rhBMP2 group ( P < .05). There was no difference in the rates of central nervous system complications or radiculitis between the 2 groups., Conclusion: Our data showed that the patients who received rhBMP2 had lower complication rates compared to the non-rhBMP2 group. However, use of rhBMP2 was associated with a higher rate of pseudarthrosis. We did not observe any difference in radiculitis and central nervous system complications between the groups., 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: ZB—Xenco Medical (consultancy), AO Spine (consultancy, past). HJM—Dr Meisel is consultant (money paid to institution) - Regenerate Life Sciences GmbH for Zyga, DiFusion (ongoing), Co.don (paid to Dr. Meisel past); royalties from: Medtronic, Fehling Aesculap (past); owns stocks (money paid to institution) - Regenerate Life Sciences GmbH in DiFusion. STY—Dr Yoon owns stock in Phygen, Alphatec; Meditech, royalties Meditech Advisors, Stryker Spine (Paid directly to institution/employer), grant from AOSpine (Paid directly to institution/employer), research support from Biomet (Research support given to AREF), non financial research support from Nuvasive and Medtronic. JAY—Royalties: NuVasive, Osprey Medical, Amedica, Integra; Stock Ownership: Benvenue Medical, Paradigm Spine, Promethean Surgical Devices, Spinal Ventures, VertiFlex, Spinicity, ISD, Providence Medical; Private Investments: Amedica, VertiFlex, Benvenue, NuVasive; Consulting: Integra, NuVasive, Amedica, HealthTrust; Board of Directors: Durango Orthopedic Associates (None); Research Support (Staff and/or Materials): Globus Medical (Paid directly to institution/employer), NuVasive (Paid directly to institution/employer), VertiFlex (Paid directly to institution/employer), Integra (Paid directly to institution/employer). DB—Consultant – Vallum, Royalties – America, DePuy Synthes, Medtronic, Fellowship Support – AOSpine (paid directly to institution). JCW—Royalties: Aesculap, Biomet, Amedica, Seaspine, Synthes; Stock Ownership: Fziomed; Private Investments: Promethean Spine, Paradigm spine, Benevenue, NexGen, Vertiflex, electrocore, surgitech, expanding orthopaedics, osprey, bone biologics, curative biosciences, pearldiver; Board of Directors: North American Spine Society (nonfinancial, reimbursement for travel for board meetings, courses, etc.), North American Spine Foundation (nonfinancial), Cervical Spine Research Society (nonfinancial, reimbursement for travel for board meetings), AO Spine/AO Foundation (honorariums for board position); Fellowship Support: AO Foundation (spine fellowship funding paid to institution).

Introduction: Two-stage limb reconstruction is an option for patients with critical size segmental bone defects following acute trauma or non-union. Reconstruction is technically demanding and associated with a high complication rate. Current protocols for limb reconstruction have well-documented challenges, and no study has reported on patient outcomes using a validated questionnaire. In this study, we aimed to examine the clinical and patient-centered outcomes following our surgical protocol for two-stage limb reconstruction following critical size segmental defects., Patients and Methods: A single surgeon performed reconstruction of long bone defects using antibiotic impregnated cement spacers and intramedullary cancellous bone autograft. A retrospective chart review was performed. Three reviewers independently measured time to union based on radiographs. The Lower Extremity Functional Scale (LEFS) survey was administered to patients after most recent follow-up., Results: Ten limbs representing nine patients were included. All patients sustained a lower extremity injury, and one patient had bilateral lower extremity injuries. Average clinical follow-up was 18.3 months (range 7-33) from final surgical intervention, and follow-up to questionnaire administration was 28 months (range 24-37). The mean time between stages was 3.1 months. Average time to unrestricted weight-bearing was 7.9 months from Stage 1 (range 3.4-15.9) and 4.5 months from Stage 2 (range 1.1-11.6). Average time to full union was 16.7 months from Stage 1 (range 6.4-28.6) and 13.5 months from Stage 2 (range 1.8-27). Eight patients (nine limbs) participated in the LEFS survey, the average score was 53.1 (range 30-67), equating to 66% of full functionality (range 38%-84%). Complications included 5 infections, 3 non-unions, and one amputation. There was a moderate positive correlation between infection at any time point and non-union (R=0.65, p=0.03)., Discussion and Conclusions: Outcomes in this small patient cohort were good despite risks of complication. There is an association between infection and non-union. Further studies addressing clinical and functional outcomes will help to guide expectations for future surgeons and patients., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Study Design: Retrospective database review., Objectives: After the Food and Drug Administration approved bone morphogenetic protein-2 (BMP) in 2002, BMP was used off-label in the cervical spine to increase bone growth and bony fusion. Since then, concerns have been raised regarding complication rates and safety. This study was conducted to examine the use of BMP in anterior cervical discectomy and fusion (ACDF) in the Medicare population and to determine risk of complications and associated costs within 90 days of surgery., Methods: Patients who underwent ACDF were identified using Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision Procedure codes (ICD9-P). Complications were identified using ICD9 diagnostic codes. Charges were calculated as amount billed, and reimbursements were calculated as amounts paid by Medicare. Data for these analyses came from a nationwide claims database., Results: A total of 215 047 patients were identified who had ACDF from 2005 to 2011. For the majority of the procedures (89.0%), BMP was not used. BMP use rose from 11.84% in 2005 to a peak of 16.73% in 2007 before decreasing to 12.01% in 2011. BMP was used 16% more in women than men. BMP use was the highest in the West (13.6%) followed by Midwest (11.8%), South (10.6%), and Northeast (7.5%). There was a higher overall complication rate in the BMP group (2.1%) compared with the non-BMP group (1.9%) (odds ratio [OR] = 1.11, 95% CI = 1.01-1.22). The BMP group also had a higher rate of wound complications (0.98% vs 0.76%, OR = 1.29, 95% CI = 1.12-1.48). In this study population, there was no difference in dysphagia/hoarseness, neurologic, medical, or other complications. During the 90-day perioperative period, BMP surgeries were charged at 17.6% higher than non-BMP surgeries., Conclusions: The use of BMP in ACDF in the Medicare population has decreased since a peak in 2007. The rate of wound and overall complications for BMP use with ACDF was higher than without. Our results regarding dysphagia/hoarseness did not show a statistically meaningful difference, which is in contrast with many other studies. Charges associated with BMP use were higher during the 90-day perioperative period., 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: The financial activities of the authors are as follows: S. Tim Yoon—Bioment, Stryker, Nuvasive, Medyssey, Meditech, Phygen, Alphatec, Medtronic; Jim A. Yousseff—Nuvasive, Integra, Amedica, HealthTrust, Osprey Biomedical, Vertiflex, Benvenue, Paradigm Spine, Promethean Surgical, ISD, Spinicity, Spinal Ventures, Providence Medical, Globus Medical; Darrel S. Brodke—Amedica, Depuy Synthes, Medtronic; Jeffrey C. Wang—Fziomed, Alphatech, Promethean Spine, Paradigm Spine, Benevenue, NexGen, Amedica, Vertiflex, Electrocore, Surgitech, VG Innovations, Corespine, Expanding Orthopaedics, Osprey, Bone Biologics, Curative Biosciences, Pearldiver, Stryker, Osprey, Aesculap, Biomet, Amedica, Seaspine, Synthes, North American Spine Society, North American Spine Foundation, Cervical Spine Research Society, AO Spine/AO Foundation, Collaborative Spine Research Foundation.

Background: Shoulder instability is commonly treated by arthroscopic stabilization. However, open stabilization procedures remain important in management of complex instability. Despite continued use of these procedures, the relative frequency of related complications remains poorly described. This study investigates current trends in open shoulder stabilization and characterizes major postoperative complications., Methods: PearlDiver, a national insurance database of orthopedic patients, was used to identify open shoulder stabilization procedures from 2007 to 2010. Current Procedural Terminology codes for 4 procedures-Bankart repair, coracoid transfer, and anterior and posterior glenoid bone grafting-were used to track procedural trends. The 1-year postoperative complications were identified and categorized into 5 groups: dislocation treated with closed reduction, closed manipulation under anesthesia, reoperation with arthroscopy, reoperation with open surgery, and others. χ 2 analysis determined statistical significance., Results: There were 2678 open shoulder stabilization procedures performed, with a 1-year complication rate of 12.3%. Relative proportion of open Bankart repairs decreased (82.5% to 69.8%), whereas proportion of coracoid transfers increased (7.7% to 19%). Posterior glenoid bone grafting had the highest complication rate (20.7%). Rate of total complications was 9.8% in patients 10-24 years, 13.6% in patients 25-54 years, and 25.9% in patients >55 years., Conclusions: Based on our patient database sample, a significant decline in the relative use of open Bankart repair was observed. Our analysis indicates that the use of bone transfer procedures was correlated with significantly higher reoperation rates than open Bankart repair, particularly in the older patient cohort. Further studies comparing open stabilization procedures with contemporary arthroscopic techniques are indicated.

Study Design: This is a cross-sectional radiologic study., Objective: The purpose of this study was to assess radiologic features related to dynamic changes of dural sac diameter using kinematic magnetic resonance imaging., Summary of Background Data: It is well known that the cross-sectional area of the lumbar spinal canal decreases during movement from flexion to extension. However, the radiologic characteristics related to dynamic changes of the lumbar spinal canal have not been elucidated., Methods: A total of 453 consecutive patients with clinically symptomatic low back pain or radiculopathy were recruited to undergo lumbar kinematic magnetic resonance imaging. The study participants consisted of 271 males (60%) and 182 females (40%). The average age was 44.5±12.2 years old. We investigated the following measurements at each level from L3-L4 to L5-S1: dural sac diameter, ligamentum flavum thickness, disk bulge, disk degeneration, angular motion, translational motion, and posterior disk height. The odds ratios (ORs) for ≥2 mm change of dural sac diameter between flexion and extension were calculated., Results: The average dural sac diameter was 12.2 mm in neutral, 12.5 mm in flexion, and 11.7 mm in extension, with an average difference between flexion and extension of 0.83 mm. The OR of a ≥2 mm change in L5-S1 was 0.55 as compared with L3-L4. Significantly increased ORs were observed with ≥3 mm of ligamentum flavum in neutral (OR: 4.05), 3-3.9 and ≥4 mm of disk bulge in neutral (ORs: 1.62 and 1.81, respectively), grade IV and V disk degeneration (OR: 2.59 and 2.86, respectively), ≥8 degrees of angular motion (OR: 1.81), and ≥2 mm of posterior disk height change (OR: 1.84)., Conclusions: Several radiologic characteristics related to the dynamic change of dural sac diameter have been demonstrated.

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: A retrospective multicenter study., Objective: Routine cervical spine surgeries are typically associated with low complication rates, but serious complications can occur. Intraoperative death is a very rare complication and there is no literature on its incidence. The purpose of this study was to determine the intraoperative mortality rates and associated risk factors in patients undergoing cervical spine surgery., Methods: Twenty-one surgical centers from the AOSpine North America Clinical Research Network participated in the study. Medical records of patients who received cervical spine surgery from January 1, 2005, to December 31, 2011, were reviewed to identify occurrence of intraoperative death., Results: A total of 258 patients across 21 centers met the inclusion criteria. Most of the surgeries were done using the anterior approach (53.9%), followed by posterior (39.1%) and circumferential (7%). Average patient age was 57.1 ± 13.2 years, and there were more male patients (54.7% male and 45.3% female). There was no case of intraoperative death., Conclusions: Death during cervical spine surgery is a very rare complication. In our multicenter study, there was a 0% mortality rate. Using an adequate surgical approach for patient diagnosis and comorbidities may be the reason how the occurrence of this catastrophic adverse event was prevented in our patient population., 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: Jeffrey C. Wang reports royalties (Aesculap, Biomet, Amedica, Seaspine, Synthes), stock ownership (Fziomed), private investments (Promethean Spine, Paradigm spine, Benevenue, NexGen, Vertiflex, electrocore, surgitech, corespine, expanding orthopaedics, osprey, bone biologics, curative biosciences, pearldiver), Board of Directors (North American Spine Society [nonfinancial, reimbursement for travel for board meetings, courses, etc.], North American Spine Foundation [nonfinancial], Cervical Spine Research Society [nonfinancial, reimbursement for travel for board meetings], AOSpine/AO Foundation [honorariums for board position], fellowship support (AO Foundation [spine fellowship funding paid to institution]; Zorica Buser reports Xenco Medical (consultancy), AOSpine (consultancy, past) Zorica Buser reports grants from AOSpine North America during the conduct of the study; David Fish 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; Allison Roe 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; Erica Gee reports grants from AOSpine North America during the conduct of the study; Erik Mayer reports grants from AOSpine North America, during the conduct of the study; Marisa Yanez reports grants from AOSpine North America during the conduct of the study; Owen McBride reports grants from AOSpine North America during the conduct of the study; Peter Cha reports grants from AOSpine North America during the conduct of the study; Paul 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; Michael G. Fehlings reports grants from AOSpine North America during the conduct of the study; 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; 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.

Study Design: Retrospective cohort study of prospectively collected data., Objective: To examine the incidence of iatrogenic spinal cord injury following elective cervical spine surgery., Methods: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was conducted. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of iatrogenic spinal cord injury., Results: In total, 3 cases of iatrogenic spinal cord injury following cervical spine surgery were identified. Institutional incidence rates ranged from 0.0% to 0.24%. Of the 3 patients with quadriplegia, one underwent anterior-only surgery with 2-level cervical corpectomy, one underwent anterior surgery with corpectomy in addition to posterior surgery, and one underwent posterior decompression and fusion surgery alone. One patient had complete neurologic recovery, one partially recovered, and one did not recover motor function., Conclusion: Iatrogenic spinal cord injury following cervical spine surgery is a rare and devastating adverse event. No standard protocol exists that can guarantee prevention of this complication, and there is a lack of consensus regarding evaluation and treatment when it does occur. Emergent imaging with magnetic resonance imaging or computed tomography myelography to evaluate for compressive etiology or malpositioned instrumentation and avoidance of hypotension should be performed in cases of intraoperative and postoperative spinal cord injury., 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: Alan H. Daniels reports grants from AOSpine North America during the conduct of the study, personal fees from Stryker, personal fees from Depuy, other from Globus, nonfinancial support from Medtronic, 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; 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; 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; 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; Ahmad Nassr reports grants from AOSpine North America during the conduct of the study; 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; Arjun S. Sebastian 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; 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 workPaul 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 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 retrospective database study., Objective: The goal of this study was to (1) evaluate the trends in the use of intraoperative neuromonitoring (ION) for anterior cervical discectomy and fusion (ACDF) surgery in the United States and (2) assess the incidence of neurological injuries after ACDFs with and without ION., Summary of Background Data: Somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs) are the commonly used ION modalities for ACDFs. Controversy exists on the routine use of ION for ACDFs and there is limited literature on national practice patterns of its use., Methods: A retrospective review was performed using the PearlDiver Patient Record Database to identify cases of spondylotic myelopathy and radiculopathy that underwent ACDF from 2007 to 2014. The type of ION modality used and the rates of neurological injury after surgery were assessed., Results: During the study period, 15,395 patients underwent an ACDF. Overall, ION was used in 2627 (17.1%) of these cases. There was a decrease in the use of ION for ACDFs from 22.8% in 2007 to 4.3% use in 2014 (P < 0.0001). The ION modalities used for these ACDFs were quite variable: SSEPs only (48.7%), MMEPs only (5.3%), and combined SSEPs and MMEPs (46.1%). Neurological injuries occurred in 0.23% and 0.27% of patients with and without ION, respectively (P = 0.84). Younger age was associated with a higher utility of ION (<45: 20.3%, 45-54: 19.3%, 55-64: 16.6%, 65-74: 14.3%, and >75: 13.6%, P < 0.0001). Significant regional variability was observed in the utility of ION for ACDFs across the country (West; 21.9%, Midwest; 12.9% (P < 0.0001)., Conclusion: There has been a significant decrease in the use of ION for ACDFs. Furthermore, there was significant age and regional variability in the use of ION for ACDFs. Use of ION does not further prevent the rate of postoperative neurological complications for ACDFs as compared with the cases without ION. The utility of routine ION for ACDFs is questionable., Level of Evidence: 3.

OBJECTIVE The efficacy of some demineralized bone matrix (DBM) substances has been demonstrated in the spinal fusion of rats; however, no previous comparative study has reported the efficacy of DBM with human mesenchymal stem cells (hMSCs). There is an added cost to the products with stem cells, which should be justified by improved osteogenic potential. The purpose of this study is to prospectively compare the fusion rates of 3 different commercially available DBM substances, both with and without hMSCs. METHODS Posterolateral fusion was performed in 32 mature athymic nude rats. Three groups of 8 rats were implanted with 1 of 3 DBMs: Trinity Evolution (DBM with stem cells), Grafton (DBM without stem cells), or DBX (DBM without stem cells). A fourth group with no implanted material was used as a control group. Radiographs were obtained at 2, 4, and 8 weeks. The rats were euthanized at 8 weeks. Overall fusion was determined by manual palpation and micro-CT. RESULTS The fusion rates at 8 weeks on the radiographs for Trinity Evolution, Grafton, and DBX were 8 of 8 rats, 3 of 8 rats, and 5 of 8 rats, respectively. A significant difference was found between Trinity Evolution and Grafton (p = 0.01). The overall fusion rates as determined by micro-CT and manual palpation for Trinity Evolution, Grafton, and DBX were 4 of 8 rats, 3 of 8 rats, and 3 of 8 rats, respectively. The Trinity Evolution substance had the highest overall fusion rate, however no significant difference was found between groups. CONCLUSIONS The efficacies of these DBM substances are demonstrated; however, the advantage of DBM with hMSCs could not be found in terms of posterolateral fusion. When evaluating spinal fusion using DBM substances, CT analysis is necessary in order to not overestimate fusion.

Background: Current studies investigating surgical treatment of distal biceps tendon tears largely consist of small, retrospective case series. The purpose of this study was to investigate the current patient demographics, surgical trends, and postoperative complication rates associated with operative treatment of distal biceps tendon tears using a large database of privately insured, non-Medicare patients., Methods: Patients who underwent surgical intervention for distal biceps tendon tears from 2007 to 2011 were identified using the PearlDiver database. Demographic and surgical data as well as postoperative complications were reviewed. Statistical analysis was performed using linear regression analysis and χ(2) tests, with statistical significance set at P < .05., Results: A total of 1443 patients underwent surgical treatment for distal biceps tendon tears. Men and patients aged 40 to 59 years accounted for 98% and 72% of the cohort, respectively. Regarding surgical technique, reinsertion to the radial tuberosity was preferred (95%) over tenodesis to the brachialis (5%) (P < .01). In total, revision surgery for tendon rerupture occurred in 5.4% of treated patients. The incidence of revision surgery for rerupture in acute and chronic distal biceps tears was 5.1% and 7.0%, respectively (P = .36). Postoperative infection and peripheral nerve injury rates were 1.1% and 0.6%, respectively., Conclusion: Surgeons strongly preferred anatomic reinsertion to the radial tuberosity for treatment, regardless of the chronicity of the injury. Postoperative complication rates were similar to those found in prior studies, although the true rate of rerupture may be higher than previously thought., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Purpose: A retrospective database review was carried out to evaluate the trends and demographics of rhBMP utilization in single-level posterior lumbar fusion (PLF) in the United States., Methods: Patients who underwent single-level PLF from 2005 to 2011 were identified by searching ICD-9 diagnosis and procedure codes in the PearlDiver Patient Records Database (PearlDiver Technologies, Fort Wayne, IN, USA), a national database of orthopaedic insurance records. The year of procedure, age, gender, and region of the United States were recorded for each patient. Results were reported for each variable as the incidence of procedures identified per 100,000 patients searched in the database., Results: Totally 5158 patients had single-level PLF in this study. The average rate of single-level PLF with rhBMP utilization maintained at a relatively stable level (19.1-23.5%) from 2005 to 2009, but sharply decreased to 6.8% in 2010 and 6.9% in 2011. The overall incidence of single-level PLF without rhBMP (1.37 cases per 100,000 patients) was more than five times of the incidence of single-level PLF with rhBMP (0.27 cases per 100,000 patients) (P < 0.01). The average rate of single-level PLF with rhBMP utilization is highest in Midwest (18.7%), followed by West (18.4%), South (16.4%) and Northeast (11.5%). The highest incidence of single-level PLF with rhBMP was observed in the group aged 70-74 years with an incidence of 0.33 per 100,000 patients., Conclusions: The incidence of rhBMP utilization in single-level PLF increased from 2006 to 2009, but dropped to a low level in 2010 and 2011. The Northeast region had the lowest incidence of rhBMP utilization. The group aged 70-74 years trended to have the higher incidence of single-level PLF with rhBMP utilization.

Purpose: A retrospective radiographic study was carried out to analyze the effect of lumbar disc herniation on the kinetic motion of adjacent segments., Methods: A total of 162 patients with low back pain or radicular pain in the lower limbs without a prior history of surgery were evaluated using kinetic magnetic resonance imaging. Translational motion, angular variation, and disc height were measured at each segment from L1-L2 to L5-S1. Other factors including the degree of disc degeneration, age, gender, and vertebral segment location were analyzed to determine any predisposing risk factors for segmental instability adjacent to disc herniations., Results: Spinal levels above the disc herniation exhibited, on average, a 6.4 % increase in translational motion per mm of disc herniation (P = 0.496) and a 21.4 % increase in angular motion per mm herniation (P = 0.447). Levels below the herniation demonstrated a 5.2 % increase in translational motion per mm of disc herniation (P = 0.428) and a decrease of 10.7 % in angular motion per mm (P = 0.726). The degree of disc degeneration had no significant correlation with adjacent level motion. Similarly, disc herniation was not significantly correlated with disc height at adjacent levels, although there was a significant relationship between gender and adjacent segment disc height., Conclusions: Although disc height, translational motion, and angular variation are significantly affected at the level of a disc herniation, no significant changes are apparent in adjacent segments. Our results indicate that herniated discs have no effect on range of motion at adjacent levels regardless of the degree of disc degeneration or the size of disc herniation, suggesting that the natural progression of disc degeneration and adjacent segment disease may be separate, unrelated processes within the lumbar spine.

Purpose: To evaluate the utilization and charges related to physical therapy (PT) after rotator cuff repair in privately insured and Medicare patients and between arthroscopic and open/mini-open repair techniques., Methods: The PearlDiver insurance database was queried for patients receiving postoperative PT using Current Procedural Terminology codes. Data were available from 2007 to 2011 for United Healthcare and from 2005 to 2011 for Medicare patients. Patients undergoing arthroscopic (CPT 29827) or open/mini-open approaches (CPT 23410, 23412, 23420) were identified in both populations. Utilization was determined by both the percentage of patients with at least one postoperative PT-related code and the average number of encounters per patient. Per-patient average charge was determined by dividing total charges within the billing period by the patient total., Results: A total of 365,891 patients undergoing rotator cuff repair were identified. There was an increase in the number of arthroscopic repairs (+29.1%, P = .027, United Healthcare; +78.9%, P < .001, Medicare) and a decrease in the number of open/mini-open repairs (-18.2%, P = .038, United Healthcare; -18.2%, P < .001, Medicare) across the study period. At 6 months postoperatively, PT utilization was greater in the United Healthcare groups (82.9% arthroscopic, 81.0% open/mini-open) than in the Medicare groups (41.8% arthroscopic, 43.2% open/mini-open). Utilization-weighted per-patient average charge was comparable among all 4 groups, with slightly higher charges in the United Healthcare groups ($3,376 arthroscopic, $3,251 open/mini-open) compared with the Medicare groups ($2,940 arthroscopic, $2,807 open/mini-open). The United Healthcare groups had a greater number of utilization-weighted billed encounters (36.1 for open/mini-open, 9.5 for arthroscopic) than their Medicare counterparts (12.8 open/mini-open, 16.7 arthroscopic)., Conclusions: Utilization of PT after rotator cuff repair is substantially higher in privately insured than in Medicare patients. Utilization rates appear to be comparable between surgical approaches. Per-patient costs were comparable irrespective of surgical approach and insurance modality., Level of Evidence: Level IV, economic., (Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to compare the latest patient demographics and rerupture rates of operative versus nonoperative treatment of acute Achilles tendon rupture in the United States., Methods: Patients undergoing treatment of an acute Achilles tendon rupture from 2007 to 2011 were identified by cross-referencing ICD-9-CM and CPT codes through the PearlDiver Patient Record Database., Results: In total, 12,570 patients were treated for an acute Achilles tendon rupture. The ratio of operative to nonoperative treatment increased from 1.41 to 1.65. Males were more likely to undergo surgery than females. There were no significant differences in short-term rerupture rate for operative (2.1%) versus nonoperative (2.4%) treatment., Conclusions: The proportion of patients who received operative treatment for an acute Achilles tendon rupture increased slightly during the 5 year period, suggesting that surgeons in the United States have been slower to adopt nonoperative treatment than their European counterparts., (Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Background: Pre- and postoperative rehabilitation are important to the management of patients with anterior cruciate ligament (ACL) reconstruction, but little attention has been given to the costs. This study evaluated the pre- and postoperative rehabilitation charges in patients with ACL reconstruction in the United States., Hypothesis: Patients receive preoperative rehabilitation less commonly than postoperative rehabilitation., Study Design: Retrospective database study., Level of Evidence: Level 4., Methods: Using the PearlDiver database, we identified patients undergoing ACL reconstruction from 2007 through 2011 using Current Procedural Terminology codes. The associated rehabilitation charges billed to insurance providers for 90 days preoperatively and 6 months postoperatively were categorized as physical therapy or as durable medical equipment (DME). The charges were examined by year and geographic region and represented as per-patient average charges (PPACs)., Results: A total of 92,179 patients were identified in the study period. The PPAC for rehabilitation was $241 during the 90-day preoperative period and $1876 for the 6-month postoperative period. Patients averaged 2 preoperative sessions for physical therapy, with 44% of patients receiving preoperative rehabilitation in contrast with an average of 17 postoperative sessions per patient in 93% of patients. Rehabilitation charges were greater postoperatively than preoperatively (P < 0.05). Preoperatively, 24% of patients received a DME, while 35% received a DME postoperatively. Preoperative rehabilitation PPACs were highest in the Northeast, followed by Midwest, South, and West (P < 0.05). There were no significant differences in postoperative rehabilitation PPACs for geographic region (P = 0.43)., Conclusion: Preoperative rehabilitation charges were lower than postoperative charges. A patient undergoing ACL reconstruction typically received 9 times more sessions of postoperative physical therapy than preoperative., Clinical Relevance: This study found that preoperative supervised rehabilitation for patients with ACL reconstruction was infrequent across the United States., (© 2015 The Author(s).)

Implant related infection following spine surgery is a devastating complication for patients and can potentially lead to significant neurological compromise, disability, morbidity, and even mortality. This paper provides an overview of the existing animal models of postoperative spine infection and highlights the strengths and weaknesses of each model. In addition, there is discussion regarding potential modifications to these animal models to better evaluate preventative and treatment strategies for this challenging complication. Current models are effective in simulating surgical procedures but fail to evaluate infection longitudinally using multiple techniques. Potential future modifications to these models include using advanced imaging technologies to evaluate infection, use of bioluminescent bacterial species, and testing of novel treatment strategies against multiple bacterial strains. There is potential to establish a postoperative spine infection model using smaller animals, such as mice, as these would be a more cost-effective screening tool for potential therapeutic interventions.

The purpose of this study was to investigate the latest trends and demographics of surgical treatment of posterior cruciate ligament (PCL) insufficiency in the United States. Patients who underwent surgical treatment of PCL insufficiency from 2007 to 2011 were identified by searching the International Classification of Diseases, Ninth Revision, Clinical Modification codes and Current Procedural Terminology codes in the PearlDiver Patient Records Database (PearlDiver Technologies, Warsaw, Indiana), a publicly available national database of insurance records. The chronicity of injury, year of procedure, age, sex, region of the United States the surgery was performed, and other concomitant meniscus and ligamentous operations were elicited for each patient. In total, 701 cases of surgical PCL procedures (222 isolated and 479 combined) were identified. More PCL surgeries were completed for acute injuries (74%) than for chronic injuries (26%). Among associated procedures, meniscectomies and meniscus repairs were performed for 293 (41%) and 51 (7%) patients, respectively. Meniscectomies were completed in 77 (35%) isolated reconstructions vs 216 (45%) combined reconstructions (P=.01; odds ratio, 0.65). Of the combined PCL surgeries, anterior cruciate ligament (ACL)/PCL was the most common (62%), followed by ACL/PCL/collateral ligament repair (11%) and PCL/other ligamentous reconstruction (9%). No specific trends were observed in the yearly number of PCL procedures performed. The peak number of isolated PCL surgeries was observed in a younger age group (20-29 years) than that of combined PCL surgeries (30-39 years) (P<.01). Surgical treatment for PCL insufficiency remains reserved for acute multiligamentous knee injuries, with ACL/PCL operations being the most common combined procedure., (Copyright 2015, SLACK Incorporated.)

Study Design: Retrospective radiographical study., Objective: To define the relationship between the grade of disc degeneration and the motion of the lumbar spine by using kinetic magnetic resonance imaging., Summary of Background Data: Disc degeneration is common after middle age. Lumbar instability has generally been recognized as a potential risk factor of low back pain. However, correlations between the grade of disc degeneration and the motion of the lumbar spine need more investigation., Methods: Kinetic magnetic resonance imaging was performed in 162 patients with symptomatic low back pain without prior history of surgery. The lumbar intervertebral discs were graded by spine surgeons according to the degenerative grading system (grades I-V). Translational motion and angular variation were measured at each segment from L1-L2 through L5-S1. The relationship between the degree of lumbar disc degeneration and extent of lumbar spine mobility was analyzed., Results: The translational motion in discs with grade I through IV increased gradually, but decreased with grade V. Compared with other less degenerative grades, grade V discs had significantly decreased total intervertebral translational motion (P < 0.05). The angular variation in discs with grade I through IV was fairly constant, but decreased with grade V. Compared with other degenerative grades (I-IV), grade V discs had significantly decreased total intervertebral translational motion (P < 0.05). For less degenerative grades I and II discs, the L2-L3 and L3-L4 segmental units contributed the majority of total angular mobility of the spine. However, for the severely degenerated segments, grade V discs, the contributions of the L2-L3 and L3-L4 significantly decreased (P < 0.01)., Conclusion: As disc degeneration developed from the normal to an increasingly severe stage, the motion of lumbar spine progressed from the normal stage to an unstable phase with higher mobility and finally to an ankylosed stage where stability was increased., Level of Evidence: 3.

Study Design: A kinematic magnetic resonance imaging study., Objective: To investigate the distribution of Schmorl nodes (SNs) in the lumbar spine in healthy adults, and determine the association with lumbar disk degeneration and lumbar spine motion., Summary of Background Data: SNs have been associated with several pathologies of the lumbar spine, although it has been demonstrated that they also occur in the healthy adult population without a clearly identified cause. A thorough understanding of SN distribution may help reveal reasons for their formation. How disk degeneration and lumbar spine motion relate to SNs is poorly understood., Methods: Kinematic magnetic resonance images (0.6 T) were available for 1179 healthy individuals from 15 to 85 years of age. Spine specialists performed computer-based measurements. All parameters were measured and calculated automatically using the eRAD PACS Viewer (eRAD Inc., version 6.2.1.1). Lumbar disk degeneration was documented according to the Pfirrmann classification system. Lumbar spine lordosis was quantified as the angle between the inferior endplate of L1 and superior endplate of S1. The level of significance was defined as P ≤ 0.05. The distribution of SNs along the lumbar spine and their relationship with age and sex was investigated using the single factor analysis of variance χ test. The relationship between SNs, age group, disk location, and overall grades of lumbar disk degeneration were investigated by multiple logistic regression analysis. Lumbar spine motion was compared between patients with and without SNs via independent t test among 585 individuals with qualified kinematic images. Multiple logistic regression analysis was performed on associations of lumbar motion range among the SN population., Results: The prevalence of SNs in our study population was 28.4%, and SNs were observed to be present more frequently in males (34.6%) than in females (20.2%) (ρ< 0.01). There was no significant difference in the incidence of SNs between age groups (ρ= 0.18). SNs were more common at the L2 and L3 vertebral bodies (14.3% and 14.4%), whereas SNs were least common at S1 vertebral bodies (1.5%). The highest incidences of SNs presentation was on disks with degeneration grade III (41.9%) and grade IV (45.3%). SN occurrence, aging, and disk location were positively correlated with lumbar disk degeneration grade. The lumbar spine range of motion was significantly different between individuals with and without SNs (31.4° vs. 37.9°, ρ< 0.01). The frequency of SNs was associated with decreased lumbar range of motion in all age groups except 51 to 60 years and 61 to 70 years., Conclusion: SNs have a high incidence in individuals without persistent lumbar disorders and were found in disks at all degrees of degeneration. SNs occurrence were positively associated with lumbar disk degeneration In addition, the presence of SNs was correlated with decreased overall lumbar motion across all age groups.

Study Design Literature review. Objective The purpose of this study is to compile and review the body of literature related to kinetic magnetic resonance imaging (kMRI) of the cervical spine. Methods A review of literature related to kMRI was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results We included 16 prospective and retrospective studies of symptomatic and asymptomatic patients who underwent kMRI of the cervical spine. Conclusions Data suggest that kMRI is able to provide meaningful information regarding changes in the cervical spine in both normal and pathologic segments. A prospective study comparing magnetic resonance imaging and kMRI is needed to confirm clinically utility of this technology.

Study Design: Retrospective analysis of kinematic magnetic resonance (MR) images., Objective: To elucidate the distribution and risk factors associated with missed dynamic stenosis in cervical spine., Summary of Background Data: Motion of the cervical spine is widely accepted to be associated with cervical spondylotic myelopathy; however, the distribution and the risk factors for dynamic spinal stenosis are not well understood., Methods: A total of 435 symptomatic patients (2610 cervical segments) obtained upright kinematic MR images in neutral, flexion, and extension postures. Spinal cord compression (SCC), spondylolisthesis, disc bulging, angular motion, translational motion, disc degeneration grade, Modic changes, segmental alignment, and developmental stenosis were all evaluated. Cervical segments C2-C3 to C7-T1 were divided into 2 groups, determined by the presence of SCC. After excluding segments with SCC in the neutral position, a multivariate logistic regression model was used to evaluate for associated risk factors of SCC in flexion and extension that were not present in the neutral position., Results: SCC in neutral position was observed in 5.3% (139/2610) of segments. After excluding these segments, missed dynamic stenosis was found in 8.3% (204/2471) of segments in extension and 1.6% (40/2471) in flexion. Missed dynamic stenosis in both extension and flexion was most frequent at C5-C6. Multivariate logistic regression analysis for dynamic stenosis in extension revealed that disc bulge greater than 2.4 mm, angular motion greater than 4.8°, moderate and severe disc degeneration, segmental kyphosis, and developmental stenosis were significant risk factors. In flexion, significant risk factors were a disc bulge of 1.9 mm or greater, moderate to severe disc degeneration, and segmental kyphosis., Conclusion: Dynamic cord compression was most common at the C5-C6 segment. Cervical segments with greater disc bulge, more severe disc degeneration, greater angular motion, segmental kyphosis, and developmental stenosis may be at risk for missed dynamic stenosis.