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Background Stability following multilevel decompressive laminectomy without fusion has been debated using in vitro biomechanical and radiographic models. However, there is a lack of information regarding clinical outcomes for these patients. The aim of the present study was to determine the association between clinical outcomes and number of levels decompressed via laminectomy for treatment of lumbar spinal stenosis. Methods We performed a retrospective cohort analysis of patients who underwent a primary lumbar laminectomy between 2009 and 2015 by senior orthopedic spine surgeons for lumbar spinal stenosis. Patients were divided into 2 groups based on the number of decompression levels: single level or 3 or more levels. Patient-reported outcomes were obtained in the form of Oswestry Disability Index (ODI) scores, visual analog scale (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey scores, and Veterans Rand 12-Item Health Mental and Physical Survey scores. Results Overall, 138 consecutive patients were assessed, of which 106 underwent a single-level and 32 underwent a 3-or-more-level laminectomy. Average follow-up was 24.2 months. There were no significant differences in the preoperative VAS back, VAS leg, or ODI scores between the single-level laminectomy and 3-or-more-level laminectomy groups. Both groups of patients experienced significant improvements in these clinical outcomes postoperatively with no clinically significant difference in the degree of improvement. Reoperation rates were low and similar between the 2 groups. Conclusions Patients undergoing decompression of 3 or more levels present with similar postoperative outcomes to those who undergo a single-level decompression for lumbar spinal stenosis. Under specific clinical and radiographic criteria, a multilevel decompression of 3 or more levels may be a safe and effective procedure with acceptable outcomes at 2 years after surgery. Level of Evidence 3.

Objective We compared the long-term clinical and radiographic outcomes after 3- and 4-level anterior cervical discectomy and fusion (ACDF) in a retrospective cohort study. Methods Patients who had undergone primary 3- or 4-level ACDF were retrospectively identified. The demographic data and patient-reported outcome measures (PROMs) were collected through a review of the medical records. PROM surveys were administered preoperatively for baseline measurements and at 1 year postoperatively. The surveys included the Neck Disability Index, 12-item short-form physical component summary, 12-item short-form mental component summary, and visual analog scale (VAS) scores for neck and arm pain. The cervical sagittal alignment parameters included C2–C7 lordosis, segmental lordosis, the sagittal vertical axis (SVA), and the T1 slope. Multivariate regression models were used to compare the changes in the PROMs and radiographic measurements over time between 3- and 4-level ACDF. Correlation coefficients were calculated to compare the delta scores for the PROMs and radiographic measurements. Results The VAS scores for neck and arm pain had significantly improved from baseline in both cohorts. Only the 3-level group showed significant improvements perioperatively in the Neck Disability Index and 12-item short-form physical component summary. No significant differences were found in the improvement in clinical outcomes between the 2 groups. The pooled results demonstrated a significant negative correlation between the perioperative changes in segmental lordosis and VAS scores for arm pain. A significant negative correlation was also found between the perioperative changes in the SVA and 12-item short-form mental component summary and VAS scores for neck pain. C2–C7 lordosis significantly increased postoperatively only in the 3-level ACDF group. Conclusions Patients undergoing both 3- and 4-level ACDF experienced significant clinical improvement without significant differences between the 2 groups. The radiographic measures of segmental lordosis and SVA also correlated with the changes in clinical outcomes.

Surgical treatment of herniated lumbar intervertebral disks is a common procedure worldwide. However, recurrent herniated nucleus pulposus (re-HNP) may develop, complicating outcomes and patient management. The purpose of this study was to utilize machine-learning (ML) analytics to predict lumbar re-HNP, whereby a personalized risk prediction can be developed as a clinical tool. A retrospective, single center study was conducted of 2630 consecutive patients that underwent lumbar microdiscectomy (mean follow-up: 22-months). Various preoperative patient pain/disability/functional profiles, imaging parameters, and anthropomorphic/demographic metrics were noted. An Extreme Gradient Boost (XGBoost) classifier was implemented to develop a predictive model identifying patients at risk for re-HNP. The model was exported to a web application software for clinical utility. There were 1608 males and 1022 females, 114 of whom experienced re-HNP. Primary herniations were central (65.8%), paracentral (17.6%), and far lateral (17.1%). The XGBoost algorithm identified multiple re-HNP predictors and was incorporated into an open-access web application software, identifying patients at low or high risk for re-HNP. Preoperative VAS leg, disability, alignment parameters, elevated body mass index, symptom duration, and age were the strongest predictors. Our predictive modeling via an ML approach of our large-scale cohort is the first study, to our knowledge, that has identified significant risk factors for the development of re-HNP after initial lumbar decompression. We developed the re-herniation after decompression (RAD) profile index that has been translated into an online screening tool to identify low–high risk patients for re-HNP. Additional validation is needed for potential global implementation.

Study Design: Retrospective cohort study. Objectives: This study aimed to address the prevalence, distribution, and clinical significance of cervical high-intensity zones (HIZs) on magnetic resonance imaging (MRI) with respect to pain and other patient-reported outcomes in the setting of patients that will undergo an anterior cervical discectomy and fusion (ACDF) procedure. Methods: A retrospective cohort study of ACDF patients surgically treated at a single center from 2008 to 2015. Based on preoperative MRI, HIZ subtypes were identified as either traditional T2-hyperintense, T1-hypointense (“single-HIZs”), or combined T1- and T2-hyperintense (“dual-HIZs”), and their level-specific prevalence was assessed. Preoperative symptoms, patient-reported outcomes, and disc degeneration pathology were assessed in relation to HIZs and HIZ subtypes. Results: Of 861 patients, 58 demonstrated evidence of HIZs in the cervical spine (6.7%). Single-HIZs and dual-HIZs comprised 63.8% and 36.2% of the overall HIZs, respectively. HIZs found outside of the planned fusion segment reported better preoperative Neck Disability Index (NDI; P = .049) and Visual Analogue Scale (VAS) Arm ( P = .014) scores relative to patients without HIZs. Furthermore, patients with single-HIZs found inside the planned fusion segment had worse VAS Neck ( P = .045) and VAS Arm ( P = .010) scores. In general, dual-HIZ patients showed no significant differences across all clinical outcomes. Conclusions: This is the first study to evaluate the clinical significance of HIZs in the cervical spine, noting level-specific and clinical outcome–specific variations. Single-HIZs were associated with significantly more pain when located inside the fusion segment, while dual-HIZs showed no associations with patient-reported outcomes. The presence of single-HIZs may correlate with concurrent spinal pathologies and should be more closely evaluated.

Discharge to acute/intermediate care facilities is a common occurrence after posterior lumbar fusion and can be associated with increased costs and complications after these procedures. This is particularly relevant with the growing popularity of bundled payment plans, creating a need to identify patients at greatest risk.To develop and validate a risk-stratification tool to identify patients at greatest risk for facility discharge after open posterior lumbar fusion.Retrospective cohort study.Patients were queried using separate databases from the institution of study and the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) for all patients undergoing open lumbar fusion between 2011 and 2018.Discharge to intermediate care and/or rehabilitation facilities.Using an 80:20 training and testing NSQIP data split, collected preoperative demographic and operative variables were used in a multivariate logistic regression to identify potential risk factors for postoperative facility discharge, retaining those with a p value.05. A nomogram was generated to develop a scoring system from this model, with probability cutoffs determined for facility discharge. This model was subsequently validated within the NSQIP database, in addition to external validation at the institution of study. Overall model performance and calibration was assessed using the Brier score and calibration plots, respectively.A total of 11,486 patients (10,453 NSQIP, 1,033 local cohort) were deemed eligible for study, of which 16.1% were discharged to facilities (16.7% NSQIP, 9.6% local cohort). Utilizing training data, age (p.001), body mass index (p.001), female sex (p.001), diabetes (p=.043), peripheral vascular disease (p=.001), cancer (p=.010), revision surgery (p.001), number of levels fused (p.001), and spondylolisthesis (p=.049) were identified as significant risk factors for facility discharge. The area under the receiver operating characteristic curve (AUC) indicated a strong predictive model (AUC=0.750), with similar predictive ability in the testing (AUC=0.757) and local data sets (AUC=0.773). Using this tool, patients identified as low- and high-risk had a 7.94% and 33.28% incidence of facility discharge in the testing data set, while rates of 4.44% and 16.33% were observed at the institution of study.Using preoperative variables as predictors, this scoring system demonstrated high efficiency in risk-stratifying patients with an approximate four to fivefold difference in rates of facility discharge after posterior lumbar fusion. This tool may help inform medical decision-making and guide reimbursement under bundled-care repayment plans.

Despite the growing senior population within the United States, there is a lack of consensus regarding the safety and efficacy of performing lumbar spinal fusion for this population.To evaluate the clinical and radiographic outcomes in different age cohorts following lumbar spinal fusion.Retrospective cohort analysis.Analysis of 1,184 patients who underwent posterolateral lumbar fusion from 2011 to 2018. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had a lumbar fracture, tumor, or infection, or had fusions involving the thoracic spine, high-grade spondylolisthesis, or concomitant deformity. Of the 1,184 patients, 850 patients were included. Patients were divided into three roughly equal groups for analysis: young (18-54 years), middle-aged (55-69 years), and senior (≥70 years).Visual Analog Scale Back/Leg pain, and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were analyzed.Several radiographic parameters were measured using plain radiographs obtained at preoperative, immediately postoperative (standing radiographs performed on postoperative day 1), and most recent follow-up visits. Preoperative and final patient-reported outcomes, along with demographic information, were obtained all patients. Binary outcome variables were compared between groups with multivariate logistic regression, and continuous outcome variables were compared using multivariate linear regression, with age 18 to 54 years used as the reference. Multivariate regressions were used to compare outcomes between cohorts while controlling baseline characteristics.A total of 850 patients were included; 330 young (38.80%), 317 middle-aged (37.30%), and 203 senior (23.90%). Seniors had higher postoperative length of stay compared to younger patients (p.001). Younger patients had worse final ODI scores compared to middle-aged patients (p=.002). Seniors had higher rates of proximal ASD (p=.002) compared to young patients. There was no difference in achievement of minimal clinically important differences (MCID) between all three groups.Senior patients have significant improvement in patient-reported clinical outcomes, despite having greater comorbidities, and longer length of stay. However, given a general lack of achievement of MCID across all cohorts, these findings suggest the need for a critical re-evaluation of the role of lumbar spinal fusion in the management of patients with refractory radiculopathic and/or neurogenic claudication symptoms.

Objective To assess the impact of Modic changes (MC) on preoperative symptoms, and postoperative outcomes in anterior cervical discectomy and fusion (ACDF) patients. Methods We performed a retrospective study of prospectively collected data of ACDF patients at a single institution. Preoperative magnetic resonance imagings were used to assess the presence of MC. MC were stratified by type and location, and compared to patients without MC. Associations with symptoms, patient-reported measures, and surgical outcomes were assessed. Results A total of 861 patients were included, with 356 patients with MC (41.3%). MC more frequently occurred at C5–6 (15.1%), and type II was the most common type (61.2%). MC were associated with advanced age (p < 0.001), more levels fused (p < 0.001), a longer duration of symptoms, but not with specific symptoms. MC at C7–T1 resulted in higher postoperative disability (p < 0.001), but did not increase risk of adjacent segment degeneration or reoperation. Conclusion This study is the first to systematically examine the impact of cervical MC, stratified by type and location, on outcomes in ACDF patients. Patients with MC were generally older, required larger fusions, and had longer duration of preoperative symptoms. While MC may not affect specific outcomes following ACDF, they may indicate a more debilitating preoperative state for patients.

Degenerative spine imaging findings have been extensively studied in the lumbar region and are associated with pain and adverse clinical outcomes after surgery. However, few studies have investigated the significance of these imaging "phenotypes" in the cervical spine. Patients with degenerative cervical spine pathology undergoing anterior cervical discectomy and fusion (ACDF) from 2008 to 2015 were retrospectively and prospectively assessed using preoperative MRI for disc degeneration, narrowing, and displacement, high-intensity zones, endplate abnormalities, Modic changes, and osteophyte formation from C2-T1. Points were assigned for these phenotypes to generate a novel Cervical Phenotype Index (CPI). Demographics were evaluated for association with phenotypes and the CPI using forward stepwise regression. Bootstrap sampling and multiple imputations assessed phenotypes and the CPI in association with patient-reported outcomes (Neck Disability Index [NDI], Visual Analog Scale [VAS]-neck, VAS-arm) and adjacent segment degeneration (ASDeg) and disease (ASDz). Of 861 patients, disc displacement was the most common (99.7%), followed by osteophytes (92.0%) and endplate abnormalities (57.3%). Most findings were associated with age and were identified at similar cervical vertebral levels; at C5-C7. Imaging phenotypes demonstrated both increased and decreased associations with adverse patient-reported outcomes and ASDeg/Dz. However, the CPI consistently predicted worse NDI (P = .012), VAS-neck (P = .007), and VAS-arm (P = .013) scores, in addition to higher odds of ASDeg (P = .002) and ASDz (P = .004). The CPI was significantly predictive of postoperative symptoms of pain/disability and ASDeg/Dz after ACDF, suggesting that the totality of degenerative findings may be more clinically relevant than individual phenotypes and that this tool may help prognosticate outcomes after surgery.

STUDY DESIGN: A retrospective study with prospectively-collected data. OBJECTIVE: To determine how type, location, and size of endplate lesions on magnetic resonance imaging (MRI) may be associated with symptoms and clinical outcomes after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Structural endplate abnormalities are important, yet understudied, phenomena in the cervical spine. ACDF is a common surgical treatment for degenerative disc disease; however, adjacent segment degeneration/disease (ASD) may develop. METHODS: Assessed the imaging, symptoms and clinical outcomes of 861 patients who underwent ACDF at a single center. MRI and plain radiographs of the cervical spine were evaluated. Endplate abnormalities on MRI were identified and stratified by type (atypical, typical), location, relation to operative levels, presence at the adjacent level, and size. These strata were assessed for association with presenting symptoms, patient-reported, and postoperative outcomes. RESULTS: Of 861 patients (mean follow-up: 17.4 months), 57.3% had evidence of endplate abnormalities, 39.0% had typical abnormalities, while 18.2% had atypical abnormalities. Patients with any endplate abnormality had greater odds of myelopathy irrespective of location or size, while sensory deficits were associated with atypical lesions (P = 0.016). Typical and atypical abnormalities demonstrated differences in patient-reported outcomes based on location relative to the fused segment. Typical variants were not associated with adverse surgical outcomes, while atypical lesions were associated with ASD (irrespective of size/location; P = 0.004) and reoperations, when a large abnormality was present at the proximal adjacent level (P = 0.025). CONCLUSION: This is the first study to examine endplate abnormalities on MRI of the cervical spine, demonstrating distinct risk profiles for symptoms, patient-reported, and surgical outcomes after ACDF. Patients with typical lesions reported worsening postoperative pain/disability, while those with atypical abnormalities experienced greater rates of ASD and reoperation. This highlights the relevance of a degenerative spine phenotypic assessment, and suggests endplate abnormalities may prognosticate clinical outcomes after surgery. LEVEL OF EVIDENCE: 3.

Study Design: Retrospective cohort. Objectives: To determine how the number of fused intervertebral levels affects radiographic parameters and clinical outcomes in patients undergoing open posterolateral lumbar fusion (PLF) for low-grade degenerative spondylolisthesis. Methods: This was a retrospective cohort study on patients who underwent open PLF for low-grade spondylolisthesis at a single institution from 2011 to 2018. Patients were divided into groups based on number of levels fused during their procedure (1, 2, or 3 or more). Preoperative and postoperative spinopelvic radiographic parameters, patient-reported outcomes (Visual Analog Scale [VAS]-back, VAS-leg, Oswestry Disability Index [ODI]), and postoperative complications were compared. Results: Of the 316 patients eligible (203 one-level, 95 two-level, 18 three or more levels), change in initial postoperative to final pelvic incidence-lumbar lordosis was greatest in 2-level fusions ( P = .039), while 3 or more level fusions had worse final pelvic tilt measures ( P = .021). In addition, multilevel fusions had worse final VAS-back scores (2-level: P = .015; 3 or more levels: P = .011), higher rates of dural tears (2-level: P = .001), reoperation (2-level: P = .039), and discharge to facility (3 or more levels: P = .047) when compared with 1-level fusions. Conclusions: Patients in multilevel fusions experienced less improvement in back pain, had more complications, and were more commonly discharged to a facility compared with single-level PLF patients. These findings are important for operative planning, for setting appropriate preoperative expectations, and for risk stratification in patients undergoing posterior lumbar fusion for low-grade spondylolisthesis.

Study Design: Retrospective cohort study. Objective: To assess the effect of diabetes mellitus (DM) on clinical and radiographic outcomes in patient with degenerative spondylolisthesis undergoing posterior lumbar spinal fusion. Methods: Analysis of patients who underwent open posterior lumbar spinal fusion from 2011 to 2018. Patients being medically treated for DM were identified and separated from nondiabetic patients. Visual analogue scale Back/Leg pain and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were also collected. Results: A total of 850 patients were included; 78 (9.20%) diabetic patients and 772 (90.80%) nondiabetic patients. Final PI-LL difference was significantly larger ( P = .032) for patients with diabetes compared to no diabetes, but there were no other significant differences between radiographic measurements, operative time, or postoperative length of stay. There were no differences in clinical outcomes between the 2 groups. Diabetic patients were found to have a higher rate of discharge to a facility following surgery ( P = .018). No differences were observed in reoperation or postoperative complication. Conclusions: While diabetic patients had more associated comorbidities compared with nondiabetic patients, they had similar patient-reported and radiographic outcomes. Similarly, there are no differences in rates of reoperation or postoperative complications. This study indicates that diabetic patients who have undergone thorough preoperative screening of related comorbidities and appropriate selection should be considered for lumbar spinal fusion.

BACKGROUND: In young and active patients, long head of biceps (LHB) tenodesis has become a common procedure for managing LHB pathology, but it remains unclear whether it is performed in isolation or along with other shoulder procedures and whether open and arthroscopic techniques produce different complications. QUESTIONS/PURPOSES: We sought to determine and compare open and arthroscopic LHB tenodesis in terms of (a) trends in overall use, (b) trends in use in isolation and in association with rotator cuff repair (RCR) and superior labral tear from anterior-to-posterior (SLAP) debridement/repair, and (c) the rates of post-operative complications. METHODS: We performed a retrospective analysis of data from an insurance database to identify LHB tenodesis procedures performed from 2011 to 2014. The overall annual rates of open and arthroscopic LHB tenodesis were determined and then stratified according to concurrent RCR and SLAP repair/debridement. A multivariate logistic regression analysis that controlled for patient demographics (age, sex, comorbidity) was performed. RESULTS: Overall, 8547 patients underwent LHB tenodesis, of which 43.5% were open and 56.5% were arthroscopic procedures. There was a significant increase in the utilization of LHB tenodesis from 2011 to 2014. In isolation, open LHB tenodesis was the more common technique overall and by year. Arthroscopic LHB tenodesis was the most common tenodesis technique performed in conjunction with RCR and SLAP repair/debridement. The overall complication rate was 2.9%; only wound dehiscence demonstrated a difference between techniques. CONCLUSIONS: The rates of open and arthroscopic LHB tenodesis procedures increased significantly from 2011 to 2014, with open techniques more common when LHB tenodesis is performed in isolation and arthroscopic techniques more common when performed as a concomitant procedure. Our use of a population database did not allow us to evaluate biomechanical or cost-related phenomena, and future research should examine these and other relevant differences between these two LHB tenodesis techniques. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11420-018-9645-1) contains supplementary material, which is available to authorized users.

This study describes a novel, combined Modic changes (MC) and structural endplate abnormality phenotype of the cervical spine, which we have termed the Modic-Endplate-Complex (MEC), and its association with preoperative symptoms and outcomes in anterior cervical discectomy and fusion (ACDF) patients. This was a retrospective study of prospectively collected data at a single institution. Preoperative cervical magnetic resonance imagings were used to assess the presence of MC and endplate abnormalities. Patients were divided into four groups: MC-only, endplate abnormality-only, the MEC and controls. The MEC was defined as the presence of both a MC and endplate abnormality in the cervical spine. Phenotypes were further stratified by location and compared to controls. Associations with patient-reported outcome measures were assessed using regression controlling for baseline characteristics. A total of 628 patients were included, with 84 MC-only, 166 endplate abnormality-only, and 187 MEC patients. Both MC (p < 0.001) and endplate abnormalities (p < 0.001) were independently associated with one another. MC at the adjacent level (p = 0.018), endplate abnormalities (regardless of location) (p = 0.001), and the MEC within the fusion segment (p = 0.027) were all associated with higher Neck Disability Index scores. Both MC within the fusion segment (p = 0.008) and endplate abnormalities within the fusion segment (p = 0.017) associated with lower Veteran's Rand 12-item scores. MC and structural endplate abnormalities commonly manifest concomitantly in patients indicated for ACDF for degenerative pathology. Patients with the endplate pathology, including the MEC phenotype, reported significantly higher levels of postoperative disability following ACDF. These findings add valuable data to the prognostic assessment of degenerative cervical spine patients.

Study Design: Original research, cross-sectional study. Objectives: Evaluate patient satisfaction with spine care delivered via telemedicine. Identify patient- and visit-based factors associated with increased satisfaction and visit preference. Methods: Telemedicine visits with a spine surgeon at 2 practices in the United States between March and May 2020 were eligible for inclusion in the study. Patients were sent an electronic survey recording overall satisfaction, technical or clinical issues encountered, and preference for a telemedicine versus an in-person visit. Factors associated with poor satisfaction and preference of telemedicine over an in-person visit were identified using multivariate logistic regression. Results: A total of 772 responses were collected. Overall, 87.7% of patients were satisfied with their telemedicine visit and 45% indicated a preference for a telemedicine visit over an in-person visit if given the option. Patients with technical or clinical issues were significantly less likely to achieve 5 out of 5 satisfaction scores and were significantly more likely to prefer an in-person visit. Patients who live less than 5 miles from their surgeon’s office and patients older than 60 years were also significantly more likely to prefer in-person visits. Conclusions: Spine telemedicine visits during the COVID-19 pandemic were associated with high patient satisfaction. Additionally, 45% of respondents indicated a preference for telemedicine versus an in-patient visit in the future. In light of these findings, telemedicine for spine care may be a preferable option for a subset of patients into the future.

Early onset adjacent segment degeneration (ASD) can be found within six months after anterior cervical discectomy and fusion (ACDF). Deficits in deep paraspinal neck muscles may be related to early onset ASD. This study aimed to determine whether the morphometry of preoperative deep neck muscles (multifidus and semispinalis cervicis) predicted early onset ASD in patients with ACDF. Thirty-two cases of early onset ASD after a two-level ACDF and 30 matched non-ASD cases were identified from a large-scale cohort. The preoperative total cross-sectional area (CSA) of bilateral deep neck muscles and the lean muscle CSAs from C3 to C7 levels were measured manually on T2-weighted magnetic resonance imaging. Paraspinal muscle CSA asymmetry at each level was calculated. A support vector machine (SVM) algorithm was used to identify demographic, radiographic, and/or muscle parameters that predicted proximal/distal ASD development. No significant between-group differences in demographic or preoperative radiographic data were noted (mean age: 52.4 ± 10.9 years). ACDFs comprised C3 to C5 (n = 9), C4 to C6 (n = 20), and C5 to C7 (n = 32) cases. Eighteen, eight, and six patients had proximal, distal, or both ASD, respectively. The SVM model achieved high accuracy (96.7%) and an area under the curve (AUC = 0.97) for predicting early onset ASD. Asymmetry of fat at C5 (coefficient: 0.06), and standardized measures of C7 lean (coefficient: 0.05) and total CSA measures (coefficient: 0.05) were the strongest predictors of early onset ASD. This is the first study to show that preoperative deep neck muscle CSA, composition, and asymmetry at C5 to C7 independently predicted postoperative early onset ASD in patients with ACDF. Paraspinal muscle assessments are recommended to identify high-risk patients for personalized intervention.

Background: Information regarding the treatment of high-grade spondylolisthesis (HGS) in adults has been previously described; however, previous descriptions of the evaluation and surgical management of HGS do not represent more recent and now established approaches. The purpose of the current review is to discuss current concepts in the evaluation and management of patients with HGS. Methods: Literature review. Results: HGS is diagnosed in up to 11.3% of adults with spondylolisthesis and typically presents as nonspecific lower back pain. Regarding evaluation, a thorough history and physical examination should be performed, which may help predict the presence of HGS. Diagnostic imaging, and specifically the use of spino-pelvic parameters, are now commonly implicated in guiding treatment course and prognosis. When surgical intervention is indicated, surgical approaches include in situ fusion variations, reduction and partial reduction with fusion, and vertebrectomy. Although the majority of studies suggest improvements with these approaches, the literature is limited by a low level of evidence with regards to the superiority of one technique when compared with others. Conclusions: HGS is a unique cause of low back pain in adults that carries considerable morbidity, but rarely presents with neurologic symptoms. Although the definitions, classifications, and methods of diagnosis of this spinal deformity have been established and accepted, the ideal surgical management of this deformity remains highly debated. Fusion in situ techniques are often technically easier to perform and provide lower risk of neurologic complications, whereas reduction and fusion techniques offer greater restoration of global spino-pelvic balance. Preoperative spino-pelvic parameters may have utility in assisting in procedural selection; however, future, higher-quality and longer-term studies are warranted to determine the optimal surgical intervention among the widely available techniques currently used, and to better define the indications for these interventions.

OBJECTIVE Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are alternative and less invasive techniques to stabilize the spine and indirectly decompress the neural elements compared with open posterior approaches. While reoperation rates have been described for open posterior lumbar surgery, there are sparse data on reoperation rates following these less invasive procedures without direct posterior decompression. This study aimed to evaluate the overall rate, cause, and timing of reoperation procedures following anterior or lateral lumbar interbody fusions without direct posterior decompression. METHODS This was a retrospective cohort study of all consecutive patients indicated for an ALIF or LLIF for lumbar spine at a single academic institution. Patients who underwent concomitant posterior fusion or direct decompression surgeries were excluded. Rates, causes, and timing of reoperations were analyzed. Patients who underwent a revision decompression were matched with patients who did not require a reoperation, and preoperative imaging characteristics were analyzed to assess for risk factors for the reoperation. RESULTS The study cohort consisted of 529 patients with an average follow-up of 2.37 years; 40.3% (213/529) and 67.3% (356/529) of patients had a minimum of 2 years and 1 year of follow-up, respectively. The total revision rate was 5.7% (30/529), with same-level revision in 3.8% (20/529) and adjacent-level revision in 1.9% (10/529) of patients. Same-level revision patients had significantly shorter time to revision (7.14 months) than adjacent-level revision patients (31.91 months) (p < 0.0001). Fifty percent of same-level revisions were for a posterior decompression. After further analysis of decompression revisions, an increased preoperative canal area was significantly associated with a lower risk of further decompression revision compared to the control group (p = 0.015; OR 0.977, 95% CI 0.959–0.995). CONCLUSIONS There was a low reoperation rate after anterior or lateral lumbar interbody fusions without direct posterior decompression. The majority of same-level reoperations were due to a need for further decompression. Smaller preoperative canal diameters were associated with the need for revision decompression.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a common surgical procedure for treatment of degenerative spondylolisthesis (DS) but remains controversial for treatment of isthmic spondylolisthesis (IS). Few studies have compared IS and DS outcomes after MIS TLIF. Therefore, the objective of the current study was to compare outcomes of patients with IS and DS after MIS TLIF. METHODS: A retrospective cohort analysis was performed on a prospectively maintained database of patients who underwent a primary, 1-level MIS TLIF for grade I or II IS or DS. Grade I and II DS and grade I IS patients were treated with MIS TLIF via a unilateral tubular approach, whereas the grade II IS patients were treated via a bilateral tubular approach. Differences in patient demographics and preoperative characteristics were assessed using independent sample t tests and χ(2) tests. The type of spondylolisthesis and its effect on postoperative outcomes was analyzed using Poisson regression with robust error variance (binary outcomes) or linear regression (continuous outcomes) adjusted for preoperative characteristics. Subgroup analysis comparing grade I IS versus DS and grade II IS versus DS was performed. RESULTS: A total of 223 patients were included (IS: 62 [27.8%]; DS: 161 [72.2%]). IS patients were younger (P < .001), had a lower comorbidity burden (P < .001), and a greater incidence of grade II spondylolisthesis (P < .001) at L5–S1 (P < .001) than the DS cohort. Patients with IS experienced longer operative times (P < .001) and lower, but not statistically significant, arthrodesis rates compared to the DS cohort. No differences were observed in the remaining preoperative patient characteristics, perioperative or postoperative outcomes. CONCLUSIONS: Despite being younger and having a lower comorbidity burden than the DS cohort, similar outcomes were observed after MIS TLIF for IS patients. LEVEL OF EVIDENCE: 3. CLINICAL RELEVANCE: These results suggest MIS TLIF is an appropriate treatment option for IS patients despite the increased instability inherent with IS.

Study Design: Retrospective cohort study. Objectives: Examine pre- and postoperative outcomes between patients presenting with a central/paracentral versus a far lateral herniated nucleus pulposus (HNP) and assess whether significantly worse postoperative outcomes, assessed via patient self-reported survey, are associated with far lateral disc herniations. Methods: We performed a retrospective cohort analysis of patients who underwent primary lumbar decompression between January 2008 and December 2015. Groups were divided based on herniation type, central/paracentral or far lateral. Patients with 3 months, or longer, of follow-up were included. Variables analyzed included demographics, American Society of Anesthesiologists (ASA) Score, Charleston Comorbidity Index (CCI), Oswestry Disability Index (ODI) scores, Visual Analog Scales (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey (SF-12) scores, and Veterans RAND 12-Item Mental and Physical Survey (VR-12) scores. Results: A total of 100 patients met the inclusion criteria. Postoperative ODI scores for central/paracentral HNP were significantly lower compared to far lateral HNP. Patients with a far lateral disc herniation presented with significantly lower preoperative SF-12 and VR-12 scores. The improvement in ODI score from preoperative to final was significantly lower in the patients presenting with a far lateral HNP. Conclusions: Although patients with far lateral HNP present with worse preoperative outcome scores, they can expect similar symptom improvement to central or paracentral herniations following discectomy. This information can be used for future surgeons when weighing conservative versus surgical treatment of far lateral herniations.

Background Context The presence of missing data is a limitation of large datasets, including the National Surgical Quality Improvement Program (NSQIP). In addressing this issue, most studies use complete case analysis, which excludes cases with missing data, thus potentially introducing selection bias. Multiple imputation, a statistically rigorous approach that approximates missing data and preserves sample size, may be an improvement over complete case analysis. Purpose The present study aims to evaluate the impact of using multiple imputation in comparison with complete case analysis for assessing the associations between preoperative laboratory values and adverse outcomes following anterior cervical discectomy and fusion (ACDF) procedures. Study Design/Setting This is a retrospective review of prospectively collected data. Patient Sample Patients undergoing one-level ACDF were identified in NSQIP 2012–2015. Outcome Measures Perioperative adverse outcome variables assessed included the occurrence of any adverse event, severe adverse events, and hospital readmission. Methods Missing preoperative albumin and hematocrit values were handled using complete case analysis and multiple imputation. These preoperative laboratory levels were then tested for associations with 30-day postoperative outcomes using logistic regression. Results A total of 11,999 patients were included. Of this cohort, 63.5% of patients had missing preoperative albumin and 9.9% had missing preoperative hematocrit. When using complete case analysis, only 4,311 patients were studied. The removed patients were significantly younger, healthier, of a common body mass index, and male. Logistic regression analysis failed to identify either preoperative hypoalbuminemia or preoperative anemia as significantly associated with adverse outcomes. When employing multiple imputation, all 11,999 patients were included. Preoperative hypoalbuminemia was significantly associated with the occurrence of any adverse event and severe adverse events. Preoperative anemia was significantly associated with the occurrence of any adverse event, severe adverse events, and hospital readmission. Conclusions Multiple imputation is a rigorous statistical procedure that is being increasingly used to address missing values in large datasets. Using this technique for ACDF avoided the loss of cases that may have affected the representativeness and power of the study and led to different results than complete case analysis. Multiple imputation should be considered for future spine studies.

STUDY DESIGN Retrospective cohort. OBJECTIVE To assess differences in baseline characteristics between sexes of patients undergoing anterior cervical discectomy and fusion (ACDF) and risk factors for adverse outcomes according to sex. SUMMARY OF BACKGROUND DATA ACDF is a common treatment for cervical spine disease. To reduce the rate of complications, risk factors associated with adverse events have been identified. However, few studies have examined the risk for inferior outcomes or complications after ACDF by sex. METHODS The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent ACDF from 2005 through 2014. Data collected included demographics, comorbidities, operative characteristics, and postoperative adverse events. Demographic and comorbidity variables were compared between men and women using chi-squared analysis. Perioperative outcomes were compared between groups using multivariate linear regression or Poisson regression with robust error variance controlling for preoperative characteristics. RESULTS In the 20,383 patients who met inclusion criteria, the male cohort was slightly older, less likely to be normal weight or morbidly obese, and had a higher incidence of diabetes and hypertension (P

The purpose of this study was to compare the rates of adjacent segment degeneration (ASD), sagittal alignment parameters, and patient-reported outcomes in patients who underwent multi-level versus single-level anterior cervical discectomy and fusion (ACDF). A retrospective cohort analysis was performed on consecutive patients who underwent an ACDF. Pre- and post-operative radiographic assessment included ASD, change in C2–C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient-reported outcomes were obtained. Of the 404 that underwent an ACDF with a minimum of 6 months of follow-up (average 28 months), there was no significant difference in the rate of radiographic ASD overall (p = 0.479) or in the proximal or distal adjacent segments on multivariate analysis. Secondarily, the multi-level fusions appear to restore significantly greater amounts of lordosis compared to single-level procedures (p

BACKGROUND Epidemiological estimates indicate a rising incidence of periprosthetic hip fractures. While native hip fractures are known to be a highly morbid condition, a significant body of research has led to improved outcomes and decreased complications following these injuries. Comparatively, little research has evaluated the relative morbidity and mortality of periprosthetic hip fractures. The purpose of this study was to compare the morbidity and mortality of periprosthetic vs native hip fractures. METHODS Using the National Surgical Quality Improvement Program (NSQIP) database, 523 periprosthetic hip fractures were matched to native hip fractures using propensity scores. The 30-day rates of complications were compared using McNemar's test. A multivariate regression was then used to determine independent risk factors for mortality following periprosthetic fracture. RESULTS Mortality was similar between groups (periprosthetic: 2.7% vs native: 3.4%; P = .49). Periprosthetic fractures exhibited a greater rate of overall (63.1% vs 38.6%; P < .001) and minor complications (59.1% vs 34.4%; P < .001). There was an increased rate of return to the operating room (7.8% vs 3.1%; P < .001) and blood transfusion in the periprosthetic group (54.9% vs 30.2%; P = .001). Age greater than 85 (odds ratio 9.21) and dependent functional status (odds ratio 5.38) were both independent risk factors for mortality following periprosthetic fracture. CONCLUSIONS While native hip fractures are known to be highly morbid, our findings suggest that periprosthetic hip fractures have a similar mortality with significantly higher short-term morbidity. Future research is warranted to better understand risk factors and prevention strategies for complications in this subset of patients.

Little research has focused on the influence of gender on postoperative morbidity following total hip arthroplasty (THA) and total knee arthroplasty (TKA). This study aimed to compare operative time, length of stay, 30-day complications, and readmissions based on patient gender.The prospectively collected National Surgical Quality Improvement Program registry from 2005 to 2014 was queried to identify primary elective THA and TKA patients. Multivariate regression was used to compare the rates of 30-day adverse events, rates of readmission, operative time, and postoperative length of stay between men and women. Multivariate analyses were controlled for baseline patient characteristics and procedure type.A total of 173,777 patients were included (63.5% TKA and 36.5% THA). Male gender increased the risk of multiple adverse events, including death (relative risk [RR] 1.1, P.001), surgical site infection (RR 1.2, P.001), sepsis (RR 1.4, P.001), cardiac arrest (RR 1.8, P.001), and return to the operating room (RR 1.3, P.001). Men had decreased overall adverse events (RR 0.8, P.001) secondary to a lower risk of urinary tract infection (RR 0.5, P.001) and blood transfusion (RR 0.7, P.001), which were prevalent adverse events. Men had an increased risk of 30-day readmission (RR 1.2, P.001), slightly increased operative time (+6 minutes, P.001), and slightly decreased length of stay (-0.2 days, P.001).Men had increased risk of multiple individual adverse events including death, surgical site infection, cardiac arrest, return to the operating room, and readmission. Conversely, women had increased risk of urinary tract infection and blood transfusion.

BACKGROUND CONTEXT Studies have shown robotically-assisted surgery demonstrates increased pedicle screw accuracy when compared to conventional freehand surgery. However, little research has been done to determine if this increased accuracy translates to improved clinical outcomes. PURPOSE The purpose of this study is to compare patient reported outcome measures (PROMs) for patients undergoing one to three level lumbar fusion using robotically-assisted vs freehand screw placement. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Patients who underwent either robotically-assisted or freehand lumbar fusion surgery of one to three levels from January 1, 2014 to August 31, 2020. OUTCOME MEASURES Oswestry Disability Index (ODI), Form-12 Physical (PCS-12) and Mental (MCS-12) Composite scores, visual analogue scale (VAS) back and leg scores, incidence of revisions and surgical complications. METHODS Clinical and surgical outcomes were compared between groups. Recovery ratios (RR) and the number of patients achieving the minimally clinically important difference (MCID) were calculated for ODI, PCS-12, MCS-12, VAS Back and VAS Leg at 1-year postoperative. Surgical outcomes included complication and revision rates. Multivariate linear regression analysis was performed to determine the effect of surgery type (robotically assisted or freehand) on PROMs, controlling for age, gender, BMI and number of levels fused. RESULTS A total of 262 patients were included in the study, 85 robotically-assisted and 177 freehand. No significant differences were found in ∆PROM scores, RR, or MCID between patients who underwent robotically-assisted vs freehand screw placement. The rates of revisions (1.70% in freehand group vs 1.18% in robotic group, p = 1.000) and complications (1.10% in freehand vs 1.18% in robotic group, p =1.000) between the two groups were not statistically significant. Controlling for demographic factors, procedure type (robot vs freehand) did not emerge as a significant predictor of ∆PROM scores on multivariate linear regression analysis. CONCLUSIONS Robotically-assisted screw placement did not result in significantly improved clinical or surgical outcomes compared to conventional freehand screw placement. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Discharge from the hospital on the day of (same-day) hip and knee arthroplasties has become more common; however, to our knowledge, few studies have compared morbidity between same-day and inpatient surgical procedures. The aims of this study were to compare matched cohorts of patients who underwent same-day and inpatient hip or knee arthroplasty in terms of postoperative complications and 30-day readmission rates.Patients who underwent primary elective total hip arthroplasty, total knee arthroplasty, or unicompartmental knee arthroplasty from 2005 to 2014 were identified from the National Surgical Quality Improvement Program registry. Patients discharged the day of the surgical procedure were matched 1:1 with patients who had an inpatient stay using propensity scores. The rates of 30-day adverse events and readmission were compared between matched cohorts using the McNemar test. Risk factors for 30-day readmission following same-day procedures were identified using multivariate regression.Of 177,818 patients identified, 1,236 (0.70%) underwent a same-day surgical procedure. After matching, there were no differences in overall adverse events or readmission between same-day and inpatient groups, although inpatients had increased thromboembolic events (p = 0.048) and same-day patients had an increased rate of return to the operating room (p = 0.016). When procedures were assessed individually, the only difference identified was that the same-day total knee arthroplasty cohort had an increased return to the operating room compared with the inpatient total knee arthroplasty cohort (p = 0.046). Body mass index of ≥35 kg/m (p = 0.035), insulin-dependent diabetes (p = 0.041), non-insulin-dependent diabetes (p = 0.013), and age of ≥85 years (p = 0.039) were associated with 30-day readmission following same-day surgical procedures. Infection was the most common reason for reoperation and readmission following same-day procedures.No significant differences in overall postoperative complications or readmission were found between matched cohorts of patients who underwent same-day and inpatient hip and knee arthroplasties, although inpatients had a higher rate of thromboembolic events and same-day patients had a higher rate of reoperation. Patients with a body mass index of ≥35 kg/m, diabetes, and an age of ≥85 years had an increased risk of 30-day readmission following same-day procedures, which was most commonly due to infection.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Although lumbar spinal stenosis often presents as a degenerative condition (degenerative stenosis [DS]), some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. Patients with CS often have a distinct pathophysiology with fewer degenerative changes but present with multilevel involvement. In the setting of neurologic symptoms, decompression alone while preserving stability has been proposed for both patient populations.The purpose of this study is to evaluate if the different etiology for narrowing in CS and DS results in a different natural history of pain progression, different locations requiring decompression, and different outcomes following a stability-preserving decompression procedure.This study used a retrospective cohort study patient sample: We retrospectively reviewed consecutive patients of a single surgeon with DS or CS who underwent surgical decompression without fusion between 2008 and 2014. Patients were excluded if they had undergone a previous lumbar surgical procedure (decompression or fusion) or follow-up less than 12 months.Pre- and postoperative clinical outcome scores including visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded. Postoperatively, data were collected regarding complications, the presence of new radicular or myelopathic symptoms, and necessity of reoperation in the lumbar spine.Demographic information included age, sex, body mass index, smoking status, and Charleston Comorbidity Index (CCI). Preoperative clinical symptoms as well as the presence of lower extremity radiculopathy and claudication were evaluated. Patients were determined to have a diagnosis of CS by the treating surgeon if primary radiographs revealed shortened pedicles and decreased cross-sectional area of the spinal canal as detailed by previous studies. Binary outcomes were compared between congenital and degenerative cohorts using bivariate and multivariate logistic regression. Multivariate regressions controlled for baseline patient and operative characteristics.The average age of the DS cohort was 66.7±10.7 years, whereas for the CS group, it was 47.1±9.2 years. Average follow-up was 27.6 months. The patients with DS had significantly more comorbidities as shown by the CCI score (2.8±1.6 vs. 0.5±0.6); p.001) and the American Society of Anesthesiologists (ASA) score ≥3 (52.8% vs. 11.1%; p.001). Patients with CS presented with higher VAS back (8.0 vs. 5.1; p=.008) and leg (7.9 vs. 4.5; p.001) scores. Patients with DS presented with significantly greater duration of preoperative back pain and leg pain (42.7 vs. 30.5 months; p=.042). Postoperatively, there were no significant differences in VAS back, leg, or ODI scores. However, a trend toward a lower VAS leg score was present in the patients with CS when compared with patients with DS (2.6±3.0 vs. 4.2±3.2; p.117). Both patient groups experienced similar levels of symptomatic relief and improvement in VAS and ODI scores. There were no significant differences in new-onset radicular symptoms requiring conservative treatment or reoperation. In both groups combined, 81.9% of patients reported resolution of lower extremity symptoms at final follow-up. Overall, 20.6% of patients experienced new lower-extremity radicular symptoms after a period of resolution of symptoms postoperatively. There were significantly more reoperations following surgical decompression in patients with DS (13.9% vs. 2.8%; p=.02).Patients with CS and patients with DS respond well to decompression alone, without a supplemental fusion, despite differences in pain experience and presentation. The localization of pathology requiring decompression is similar. The patients with DS were more susceptible to require another operation resulting in a fusion, which confirms the theory that initial microinstability can progress in DS, but is likely not part of the disease process in CS. At just over 2 years after decompression, patients with CS may not need to be treated by a fusion in the setting of lower back pain; however, longer-term follow up is necessary to further assess these outcomes.

Background Quality improvement in orthopaedic surgery has received increasing attention; however, there is insufficient information available about the perioperative safety of many common pediatric orthopaedic procedures. This study aimed to characterize the incidence of adverse events in a national pediatric patient sample to understand the risk profiles of common pediatric orthopaedic procedures, and to identify patients and operations that are associated with increased rates of adverse outcomes. Methods A retrospective cohort study was conducted using the prospectively collected American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Pediatric database. Pediatric patients who underwent 29 different orthopaedic procedures were identified in the 2012 NSQIP Pediatric database. The occurrence of any adverse event, infection, return to the operating room, and readmission within 30 days, were reported for each procedure. Multivariate regression was then used to identify the association of patient and operative characteristics with the occurrence of each adverse outcome. Results A total of 8975 pediatric patients were identified. Supracondylar humerus fracture fixation was the most common procedure performed in this sample (2274 patients or 25.57% of all procedures), followed by posterior spinal fusion (1894 patients or 21.10% of all procedures). Adverse events occurred in 352 patients (3.92% of all patients). Four deaths were noted (0.04% of all patients), which only occurred in patients with nonidiopathic scoliosis undergoing spinal fusion. Infections occurred in 143 patients (1.59%), and 197 patients (2.19%) were readmitted within 30 days. Multiple patient characteristics and procedures were found to be associated with each adverse outcome studied. Conclusions Spinal fusion, multiaxial external fixation, and fasciotomy were procedures associated with increased rates of adverse outcomes within 30 days. Patients with obesity, ASA class ≥3, and impaired cognitive status also had increased rates of adverse outcomes. The results from this study of a large, national sample of pediatric orthopaedic patients are important for benchmarking and highlight areas for quality improvement. Level of evidence Level III-Prognostic.

STUDY DESIGN A retrospective analysis. OBJECTIVE The aim of this study was to quantify improvements in Visual Analogue Scale (VAS) neck and arm pain, Neck Disability Index (NDI), and Short Form-12 (SF-12) Mental (MCS) and Physical (PCS) Composite scores following an anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA ACDF is evaluated with patient-reported outcomes. However, the extent to which these outcomes improve following ACDF remains poorly defined. METHODS A surgical registry of patients who underwent primary, one- or two-level ACDF during 2013 to 2015 was reviewed. Comparisons of VAS neck and arm, NDI, and SF-12 MCS and PCS scores were performed using paired t tests from preoperative to each postoperative time point. Analysis of variance (ANOVA) was used to estimate the reduction in neck and arm pain over the first postoperative year. Subgroup analyses were performed for patients with predominant neck (pNP) or arm (pAP) pain, as well as for one- versus two-level ACDF. RESULTS Eighty-nine patients were identified. VAS neck and arm, NDI, and SF-12 PCS improved from preoperative scores at all postoperative time points (P

Aims The aim of the present study was to compare the 30- and 90-day re-admission rates and complication rates of outpatient and inpatient total shoulder arthroplasty (TSA). Patients and Methods The United States Medicare Standard Analytical Files database was questioned to identify patients who had undergone outpatient or inpatient TSA between 2005 and 2012. Patient characteristics were compared between the two groups using chi-squared analysis. Multivariate logistic regression analysis was used to control for differences in baseline patient characteristics and to compare the two groups in terms of post-operative complications within 90 days and re-admission within 30 days and 90 days. Results A total of 123 347 Medicare subscribers underwent TSA between 2005 and 2012; 3493 (2.8%) had the procedure performed as an outpatient. A significantly greater proportion of patients who underwent TSA as inpatients were women, had a history of smoking, and had a greater incidence of medical comorbidity including diabetes, coronary artery disease, congestive heart failure, and chronic kidney disease (p < 0.05 for all). Re-admission rates were significantly higher for inpatients at both 30 days (0.83% versus 0.60%, p = 0.016, odds ratio 1.8) and 90 days (2.87% versus 2.04%, p < 0.001, odds ratio 1.8). Complications, including thromboembolic events (p < 0.001) and surgical site infection (p = 0.002), were significantly higher in inpatients. Conclusion Patients who underwent TSA on an outpatient basis were overall younger and healthier than those who had inpatient surgery, which suggests that patient selection was taking place. After controlling for age, gender, and medical conditions, patients who underwent TSA as outpatients had lower rates of 30- and 90-day re-admission and a lower rate of complications than inpatients. Cite this article: Bone Joint J 2017;99-B:934–8

Background Context Multiple methods are used to measure proximal junctional angle (PJA) and diagnose proximal junctional kyphosis (PJK) after fusion for adolescent idiopathic scoliosis (AIS); however, there is no gold standard. Previous studies using the three most common measurement methods, upper-instrumented vertebra (UIV)+1, UIV+2, and UIV to T2, have minimized the difficulty in obtaining these measurements, and often exclude patients for which measurements cannot be recorded. Purpose The purpose of this study is to assess the technical feasibility of measuring PJA and PJK in a series of AIS patients who have undergone posterior instrumented fusion and to assess the variability in results depending on the measurement technique used. Study Design/Setting A retrospective cohort study was carried out. Patient Sample There were 460 radiographs from 98 patients with AIS who underwent posterior spinal fusion at a single institution from 2006 through 2012. Outcome Measures The outcomes for this study were the ability to obtain a PJA measurement for each method, the ability to diagnose PJK, and the inter- and intra-rater reliability of these measurements. Methods Proximal junctional angle was determined by measuring the sagittal Cobb angle on preoperative and postoperative lateral upright films using the three most common methods (UIV+1, UIV+2, and UIV to T2). The ability to obtain a PJA measurement, the ability to assess PJK, and the total number of patients with a PJK diagnosis were tabulated for each method based on established definitions. Intra- and inter-rater reliability of each measurement method was assessed using intra-class correlation coefficients (ICCs). Results A total of 460 radiographs from 98 patients were evaluated. The average number of radiographs per patient was 5.3±1.7 (mean±standard deviation), with an average follow-up of 2.1 years (780±562 days). A PJA measurement was only readable on 13%–18% of preoperative filmsand 31%–49% of postoperative films (range based on measurement technique). Only 12%–31% of films were able to be assessed for PJK based on established definitions. The rate of PJK diagnosis ranged from 1% to 29%. Of these diagnoses, 21%–100% disappeared on at least one subsequent film for the given patient. ICC ranges for intra-rater and inter-rater reliability were 0.730–0.799 and 0.794–0.836, respectively. Conclusions This study suggests significant limitations of the three most common methods of measuring and diagnosing PJK. The results of studies using these methods can be significantly affected based on the exclusion of patients for whom measurements cannot be made and choice of measurement technique.

STUDY DESIGN Retrospective cohort study. OBJECTIVE To compare short-term morbidity for primary and revision anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA Revision ACDF procedures are relatively common, yet their risks are poorly characterized in the literature. There is a need to assess the relative risk of revision ACDF procedures compared with primary surgery. METHODS The prospectively collected American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent primary and revision ACDF from 2005 to 2014. The occurrence of 30-day postoperative complications, readmission, operative time, and postoperative length of stay were compared between primary and revision procedures using multivariate regression to control for patient and operative characteristics. RESULTS A total of 20,383 ACDF procedures were identified, 1219 (6.0%) of which were revision cases. On multivariate analysis, revision procedures were associated with significantly increased risk of any adverse event (relative risk [RR] 2.3, P

BACKGROUND CONTEXT Herniations of lumbar intervertebral discs are one of the most common injuries sustained across the United States, and present challenges in management for the spine surgeon. Though patients often experience symptomatic relief following surgical decompression, reherniation is a common, yet unpredictable occurrence that may lead to further adverse outcomes. PURPOSE The purpose of this study was to create a prognostic tool to identify patients at greatest risk for reherniation after surgery. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Patients were identified by reviewing magnetic resonance imaging (MRI) studies and clinical documentation to identify all patients receiving surgical decompression of the lumbar spine for a herniated nucleus pulposus (HNP) from 2006 to 2018. OUTCOME MEASURES Reherniation of a lumbar intervertebral disc after decompression surgery. METHODS Following identification of the eligible cohort, patient charts were subsequently queried for type, location and incidence of reherniation events after decompression surgery. Baseline demographic (age, sex, body mass index (BMI), American Society of Anesthesiologist (ASA) Class, smoking history), clinical (duration of symptoms, type of herniation, number of planned operative levels), and radiographic information (pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), coronal angulation (CA), lumbar lordosis (LL)) was also collected. Following an 80:20 training and testing data split, multiple imputation and LASSO logistic regression were employed to build and validate a predictive model to identify patients at risk for reherniations after surgery. Ten folds of cross-validation were used to identify tuning parameters for the LASSO logistic regression model, allowing for selection of the strongest predictors for reherniation events. This model was subsequently refit to the multiply-imputed data to allow calculation of pooled model estimates. A threshold to distinguish patients as low- or high-risk for reherniations was established using Youden's index. The threshold for statistical significance was set p RESULTS A total of 517 patients (318 male, 199 female) presented for surgical decompression of a lumbar HNP, in which 51 experienced reherniations after surgery. Patients had a mean age of 45.2±13.9 years, BMI of 29.4±6.3 kg/m2, and 22.4±28.0 months of follow-up. Most herniations were paracentral (431/517; 83.4%), followed by central (55/517; 10.6%), and far lateral (29/517; 5.6%). Reherniations were seen at a mean of 46.0±70.0 months after surgery. LASSO logistic regression identified nine significant predictors for reherniations: age, sex, ASA class, operative levels, duration of preoperative symptoms, paracentral disc herniation, preoperative PI, preoperative LL, and VAS-Leg scores. Paracentral disc herniations and duration of preoperative symptoms were the strongest positive and negative predictors for reherniation outcomes, respectively. Validation of this model demonstrated excellent model discrimination (AUC: 0.834), sensitivity (71.4%), and specificity (87.6%). Within the testing cohort, 16.3% and 83.7% of patients were identified as high- and low-risk, respectively. Of these, 29.4% of high-risk patients (5/17) sustained future reherniations, while nearly all low-risk patients (85/87; 98.7%) experienced no recurrence of their HNP. CONCLUSIONS This is the first study to develop and validate a screening tool to identify patients with clear differences in risk for reherniation after lumbar decompression for HNP. With further validation, this tool can be readily implemented in clinical practice, and may accurately identify patients likely to experience lasting surgical benefit for lumbar disc herniations. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Retrospective cohort study.To compare clinical outcomes after anterior cervical discectomy and fusion (ACDF) based on preoperative duration of radiculopathy symptoms.There is no clear indication of when outcomes after ACDF become less effective in the setting of acute versus chronic symptoms from cervical nerve root compression.A retrospective cohort study of consecutive patients who underwent an ACDF between 2008 and 2015 for radiculopathy was performed. Patients were divided into 3 groups: radicular symptoms lasting for6 months, symptoms lasting for 6-12 months, and those with symptoms for ≥12 months. Neck Disability Index (NDI) and Visual Analog Scale (VAS) scores for both the neck and arms were obtained at preoperative and final postoperative visits. Radiographs were assessed for adjacent segment degeneration, fusion, and subsidence. Bivariate and multivariate regressions were subsequently used to compare outcomes between groups.A total of 379 patients were included. Patients with symptoms lasting for 6-12 months and those with symptoms lasting for ≥12 months had worse preoperative VAS neck pain compared with patients with symptoms lasting for6 months (P=0.000 and P=0.004, respectively). Patients with symptoms lasting for ≥12 months had worse baseline functional status compared with patients with symptoms lasting for6 months (P=0.009). At final follow-up, there were no significant differences in VAS neck, VAS arm, or NDI between symptom duration groups. However, differences in outcomes were noted when considering the type of preoperative symptom. Patients with pain symptoms of ≥12 months had worse preoperative VAS neck (P=0.001), VAS arm (P=0.008), and NDI (P0.001) and had significantly worse final VAS arm (P=0.019) and NDI (P=0.016) compared with patients with preoperative pain symptoms lasting for6 months. The overall reoperation rate was 4.5%. Fusion was achieved in 97.6% of the patients, and subsidence was observed in 5.5%. There were no significant differences in the risk of adjacent segment degeneration, reoperations, fusion rates, or subsidence rates based on preoperative symptom duration.Despite worse preoperative neck pain and functional status in patients with preoperative duration of symptoms6 months, there were no differences in final clinical outcomes across groups.

STUDY DESIGN Retrospective cohort study at a single institution. OBJECTIVE To examine the effect of symptom duration on clinical outcomes after posterolateral lumbar fusion. SUMMARY OF BACKGROUND DATA Nonoperative measures are generally exhausted before patients are indicated for surgical intervention, leaving patients with their symptomatology for varying lengths of time. It is unclear at what point in time surgical intervention may become less efficacious at alleviating preoperative symptoms. MATERIALS AND METHODS Consecutive patients who underwent primary elective open posterior lumbar spinal fusion at a single academic institution were included. Patient and operative characteristics were compared between symptom duration groups (group 1

Outpatient lumbar spinal fusion surgery has the potential for improved patient satisfaction, speed of recovery, and economic advantages when compared to inpatient surgery. Despite the rise in the number of these procedures performed annually, the literature on this topic remains scarce. As such, there is a need for a comprehensive review of current concepts in indications and management. The current review will present the most recent literature regarding pre-operative, intra-operative, and post-operative considerations when performing outpatient lumbar spinal fusion surgery.

Recent advancements in medical technology have led to the emergence of robotic-assisted surgery with the hope of creating a safer and more efficient surgical environment for the patient and surgical team. Spine surgery and spine tumor surgery involve challenging anatomy and demand highly precise surgical maneuvers, creating an important niche for robotic systems. While still in its infancy, robotics in spine surgery have proven successful in pedicle screw placement. Similarly, robotics has begun to be used for accurate resections and surgical planning in tumor surgery. As future studies are published and robotics systems continue to evolve, we can expect more tactile haptic feedback and implementation of useful instruments to improve preoperative planning, resection guidance, and reconstruction during spine tumor surgery.

Patients with back pain predominance (BPP) have traditionally been thought to derive less predictable symptomatic relief from lumbar fusion surgery.To compare postoperative clinical outcomes as well as degree of improvement in clinical outcome measures between patients with BPP and patients with leg pain predominance (LPP) undergoing open posterior lumbar fusion.Retrospective cohort study.Analysis of patients who underwent an open posterior lumbar fusion for low-grade (Meyerding Grade I or II) degenerative or isthmic spondylolisthesis from 2011 to 2018 was conducted. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had less than 6 months of follow-up, presented with a lumbar vertebral body fracture, tumor, or infection, or underwent a fusion surgery that extended to the thoracic spine, high-grade spondylolisthesis, or concomitant deformity.Radiographs obtained at preoperative, immediate postoperative, and final visits were evaluated for presence or absence of fusion. Patient-reported outcomes were recorded at preoperative and final clinic visits that included: visual analog scale (VAS) back/leg pain, and Oswestry disability index (ODI). Achievement of minimal clinically important difference (MCID) was analyzed, along with rates of postoperative complication and reoperation.Preoperative and final patient-reported outcomes were obtained. Achievement of MCID was evaluated using following thresholds: ODI 14.9, VAS-back pain 2.1, VAS-leg pain 2.8. For analysis, patients were divided into two groups based on predominant location of pain: predominantly VAS-back pain (BPP) and predominantly VAS-leg pain (LPP).One hundred forty-one patients met inclusion criteria. Of these, 71 had LPP, and 70 had BPP. Patients with preoperative LPP experienced greater improvements in VAS-leg (p.001) compared to those with BPP, whereas patients with preoperative BPP experienced greater improvements in VAS-back (p=.011) postoperatively compared to those with LPP. There were no differences in the final clinical outcomes. Additionally, LPP achieved MCID for VAS-leg (p=.027) at significantly higher proportion than BPP and BPP achieved MCID for VAS-back (p=.050) at significantly higher proportion than LPP.Patients with low-grade spondylolisthesis who underwent an open posterior lumbar fusion had improvement in symptoms regardless of presentation with BPP or LPP. In properly indicated patients, posterior spinal fusion is effective for those with BPP in the setting of experiencing both leg and back pain, and clinicians can use this information for perioperative discussions and surgical decision-making.

Study design A retrospective study of patients undergoing anterior cervical discectomy and fusion (ACDF) in the prospective National Surgical Quality Improvement Program (NSQIP) database. Objective To determine the most common reasons for readmission within 30 days after elective ACDF. Summary of background data ACDF is a commonly performed surgery that is safe and effective for treating a variety of cervical spine pathologies. With new quality-based reimbursements tied to readmissions within 30 days of discharge, better understanding of the causes of readmissions is, however, needed. Methods Patients undergoing ACDF in the NSQIP database from 2012 to 2014 were reviewed. The overall rate of readmission and documented reasons for readmission were collected. Multivariate regression was then used to determine risk factors for readmissions. Results A total of 17,088 patients undergoing elective ACDF were identified. There were 545 (3.2%) readmissions within 30 postoperative days. Of the readmitted patients, 293 (53.8%) were readmitted for nonsurgical site-related reasons, with neuropsychiatric (n = 44), cardiovascular (n = 39), and pneumonia (n = 37) being the most common reasons. A total of 184 patients (33.8%) were readmitted for surgical site-related reasons, with surgical site infection (n = 42), hemorrhage/hematoma (n = 42), and dysphagia (n = 32) being the most common reasons. A total of 84 patients (15.6%) had undocumented reasons for readmission. In multivariate analysis, only older age and higher American Society of Anesthesiologists class were independently associated with readmissions. Conclusion Most readmissions after ACDF were due to nonsurgical site-related reasons, suggesting the importance of careful patient selection, aggressive preoperative medical optimization, and adequate postoperative management. Level of evidence 3.

Background The rate of total shoulder arthroplasty (TSA) is rising, which has an impact on health care expenditure. One avenue to mitigate cost is outpatient TSA. There are currently no published reports of this practice. In this study, we determine the 30-day adverse event and readmission rates after outpatient TSA and compare these rates with inpatient TSA. Methods A retrospective cohort study using a population database in the United States was undertaken. Patients who underwent primary TSA between 2005 and 2014 were identified and divided into 2 cohorts based on length of stay (LOS): outpatient TSA (LOS 0 days) and inpatient TSA (LOS >0 days). Patient and procedure characteristics were collected. The 30-day adverse event and readmission rates were calculated for each cohort. A multivariate logistic regression determined if the odds of an adverse event or readmission were significantly different between the inpatient and outpatient TSA cohorts. Results Overall, 7197 patients in this database underwent TSA between 2005 and 2014, of which 173 patients (2.4%) underwent outpatient TSA. The 30-day adverse event rate in the outpatient and inpatient TSA cohorts was 2.31% and 7.89%, respectively. The 30-day readmission rate in the outpatient and inpatient TSA cohorts was 1.74% and 2.93%, respectively. In the multivariate logistic regression, the odds of an adverse event or readmission were not significantly different (odds ratio of 0.4 [ P = .077] and odds ratio of 0.7 [ P = .623], respectively). Conclusion There are no significant differences in the 30-day adverse event and readmission rates between outpatient and inpatient TSA. In the appropriately selected patient, outpatient TSA is safe and cost-effective.

STUDY DESIGN Retrospective study of data collected prospectively by the American College of Surgeons National Surgical Quality Improvement Program. OBJECTIVE To determine the incidence and risk factors for development of pneumonia after posterior lumbar fusion (PLF). SUMMARY OF BACKGROUND DATA Postoperative pneumonia has important clinical consequences for patients and the health care system. Few studies have examined pneumonia after spinal fusion procedures. METHODS Patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent PLF during 2005 to 2013 were included. The primary outcome was a diagnosis of pneumonia within the first 30 postoperative days. Independent risk factors for the development of postoperative pneumonia were identified using multivariate regression. Rates of sepsis and mortality were compared between patients who did and did not develop pneumonia using multivariate regression that adjusted for all demographic, comorbidity, and procedural characteristics. RESULTS A total of 12,428 patients undergoing PLF were identified. The incidence of pneumonia was 0.59%. Independent risk factors for the development of pneumonia were chronic obstructive pulmonary disease (relative risk [RR] = 2.7, P = 0.006), steroid use (RR = 2.6, P = 0.017), non-insulin-dependent diabetes mellitus (DM) (RR = 2.4, P = 0.003), insulin-dependent DM (RR = 2.9, P = 0.005), and greater number of operative levels (two level: RR = 1.7, P = 0.033; three level: RR = 2.7, P = 0.007). Patients who developed pneumonia had a higher rate of sepsis (15.1% vs. 0.8%, adjusted RR = 14.5, P

Alpine skiing and snowboarding are both popular winter sports that can be associated with significant orthopaedic injuries. However, there is a lack of nationally representative injury data for the two sports. The National Trauma Data Bank was queried for patients presenting to emergency departments due to injuries sustained from skiing and snowboarding during 2011 and 2012. Patient demographics, comorbidities, and injury patterns were tabulated and compared between skiing and snowboarding. Risk factors for increased injury severity score and lack of helmet use were identified using multivariate logistic regression. Of the 6055 patients identified, 55.2 % were skiers. Sixty-one percent had fractures. Lower extremity fractures were the most common injury and occurred more often in skiers (p

STUDY DESIGN Retrospective analysis of a prospectively maintained surgical registry. OBJECTIVE To examine the association between body mass index (BMI) and the risk for undergoing a revision procedure following a single-level minimally invasive (MIS) lumbar discectomy (LD). SUMMARY OF BACKGROUND DATA Studies conflict as to whether greater BMI contributes to recurrent herniation and the need for revision procedures following LD. Patients and surgeons would benefit from knowing whether greater BMI is a risk factor to guide the decision whether to pursue an operative versus non-operative treatment. METHODS Patients undergoing a single-level MIS LD were retrospectively identified in our institution's prospectively maintained surgical registry. BMI was categorized as normal weight (

Introduction This study compared complication rates between pedicle flaps and free flaps used for resurfacing of intraoperative brachytherapy (IOBT) implants placed following head and neck tumour extirpation to help clarify the ideal reconstructive procedure for this scenario. Patients and methods A retrospective review of reconstructions with IOBT at our institution was conducted. Patient and treatment details were recorded, as were the number and type of flap complications, including re-operations. Logistic regressions compared complications between flap groups. Results Fifty free flaps and 55 pedicle flaps were included. On multivariate analysis, free flap reconstruction with IOBT was significantly associated with both an increased risk of having any flap complication (OR = 2.9, p = 0.037) and with need for operative revision (OR = 3.5, p = 0.048) compared to pedicle flap reconstruction. Conclusions In the setting of IOBT, free flaps are associated with an increased risk of having complications and requiring operative revisions.

It is not known which adverse events occur more commonly following revision than following primary total joint arthroplasty.Patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) during 2011 to 2013 as part of the America College of Surgeons National Surgical Quality Improvement Program were identified. Rates of adverse events were compared between patients undergoing primary and patients undergoing revision procedures with adjustments for demographic and comorbidity characteristics.In total, 48307 THA patients and 70605 TKA patients met inclusion criteria. Of the THA patients, 43247 (89.5%) underwent primary procedures, while 5060 (10.5%) underwent revision procedures. Of the TKA patients, 65694 (93.0%) underwent primary procedures, while 4911 (7.0%) underwent revision procedures. Patients undergoing revision procedures had higher rates of systemic sepsis (for THA, 0.3% vs 0.1%, adjusted relative risk [RR], 3.5; 95% confidence interval [CI], 1.7-7.0; P.001; for TKA, 0.3% vs 0.1%, adjusted RR, 3.0; 95% CI, 1.7-5.2, P.001), deep incisional surgical site infection (for THA, 1.3% vs 0.3%, adjusted RR, 4.3; 95% CI, 3.2-5.8, P.001; for TKA, 0.7 vs 0.2%, RR, 4.0; 95% CI, 2.7-5.9, P.001), and organ/space infection (for THA, 1.8% vs 0.2%, RR, 7.4; 95% CI, 5.4-10.0, P.001; for TKA, 1.1% vs 0.1%, adjusted RR, 7.5; 95% CI, 5.4-10.6, P.001). Patients undergoing revision procedures did not have higher rates of pulmonary embolism or deep vein thrombosis (P ≥ .05 for each).Public reporting of adverse events should be interpreted in the context of the differences between primary and revision procedures, and reimbursement systems should reflect the greater amount of postoperative care that patients undergoing revision procedures require.

STUDY DESIGN Retrospective review of the prospective American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) database with 30-day follow-up of 2164 patients undergoing elective anterior cervical discectomy and fusion (ACDF). OBJECTIVE To determine factors independently associated with increased length of stay (LOS) and complications after ACDF to facilitate preoperative planning and setting of realistic expectations for patients and providers. SUMMARY OF BACKGROUND DATA The effect of individual preoperative factors on LOS and complications has been evaluated in small-scale studies. Large database analysis with multivariate analysis of these variables has not been reported. METHODS The ACS NSQIP database from 2005 to 2010 was queried for patients undergoing ACDF procedures. Preoperative and perioperative variables were collected. Multivariate regression determined significant predictors (P

To determine (1) the incidence of delayed surgical treatment, (2) risk factors associated with delayed surgical intervention, (3) inpatient adverse events and discharge disposition, and (4) the association of delayed surgery with inpatient adverse events.Retrospective cohort study.2011 and 2012 National Trauma Data Bank.All adult patients younger than 50 years of age with femoral neck fractures.Not applicable.(1) Time to surgical intervention after inpatient admission, (2) odds ratio (OR) for delayed surgery (later than 24 hours after admission), (3) incidence of inpatient adverse events and discharge disposition, (3) rates of inpatient adverse events and discharge disposition, and (4) OR for occurrence of serious adverse events, minor adverse events, and any adverse events.Of a total of 1361 patients, 67.8% of patients underwent surgery within 24 hours of presentation. In multivariate analysis (controlling for patient and injury characteristics), Charlson comorbidity index of 3+ compared with Charlson comorbidity index of 0 (OR: 3.62), pelvic fracture (OR: 2.01), and treatment at an American College of Surgeons level I trauma center (compared with levels II-IV; OR: 1.56) were associated with delayed surgery. The overall rate of mortality and inpatient adverse events was 0.2% and 12.1%, respectively. Delayed surgery was independently associated with increased occurrence of serious adverse events, minor adverse events, and any adverse events.Although a majority of nonelderly patients with femoral neck fractures underwent surgery within the first 24 hours of admission and had good outcomes in the short-term, certain subpopulations have a higher risk of delayed surgery. As delayed surgery is associated with worse outcomes, and short-term and long-term outcomes, efforts should focus on expediting care of these patients.Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Background:Whether resident involvement in surgical procedures affects intra- and/or postoperative outcomes is controversial.Purpose/Hypothesis:The purpose of this study was to compare operative time, adverse events, and readmission rate for arthroscopic knee surgery cases with and without resident involvement. We hypothesized that resident involvement would not negatively affect these variables.Study Design:Cohort study; Level of evidence, 3.Methods:A retrospective review of the prospectively maintained National Surgical Quality Improvement Program was performed. Patients who underwent arthroscopic knee surgery between 2005 and 2012 were identified. Multivariate Poisson regression with robust error variance was used to compare the rates of postoperative adverse events and readmission within 30 days between cases with and without resident involvement. Multivariate linear regression was used to compare operative time between cohorts. Because of multiple statistical comparisons, a Bonferroni correction was used, and statistical significance was set at P < .004.Results:A total of 29,539 patients who underwent arthroscopic knee surgery were included in the study, and 11.3% of these patients had a resident involved with the case. The overall rate of adverse events was 1.62%. On multivariate analysis, resident involvement was not associated with increased rates of adverse events or readmission. Resident cases had a mean 6-minute increase in operative time ( P < .001).Conclusion:Overall, resident involvement in arthroscopic knee surgery was not associated with an increased risk of adverse events or readmission. Resident involvement was associated with only a mean increased operative time of 6 minutes, a difference that is not likely to be clinically significant. These results support the safety of resident involvement with arthroscopic knee surgery.

BACKGROUND CONTEXT Anterior lumbar interbody fusion (ALIF) has shown significant improvements in clinical outcomes for patients with degenerative disc disease causing lower back pain and foraminal stenosis. However, few studies have examined if there is a difference between outcomes in single level vs two level standalone ALIF. PURPOSE The purpose of this study was to assess for a difference in outcomes in single level vs two-level ALIF. STUDY DESIGN/SETTING Retrospective cohort study of patients treated at a single academic institution by a single surgeon. PATIENT SAMPLE Consecutive adult patients from 2011 to 2019 with the diagnosis of degenerative disc disease who underwent a single level (L5-S1) vs two level (L4-S1) standalone ALIF were included in this study. Only patients with 6 months of follow-up were analyzed. OUTCOME MEASURES Patient demographic data including age, body mass index, gender and American Society of Anesthesiologists classification was collected. Visual analog scale (VAS) pain scores for the back and leg, Oswestry Disability Index (ODI), Short Form 12 (SF-12) and Veterans RAND 12 (VR-12) scores were collected for clinical outcomes preoperatively and at the final postoperative visit. METHODS This study was a retrospective review of prospectively collected data. The patients were divided into cohorts of single level vs level ALIFs. Demographic data was compared between the two cohorts to look for baseline differences. Changes between preoperative and final clinical outcomes were compared using bivariate and multivariate linear regressions. Patients who achieved the minimal clinically important difference (MCID) in VAS and ODI scores from both groups were further analyzed with bivariate and multivariate linear regressions to assess for significant differences in outcomes. RESULTS A total of 73 patients were included. Fifty-six (76.7%) underwent a single level ALIF and 17 (23.3%) underwent two level ALIF. There were no baseline differences in patient demographics, nor in preoperative clinical scores. Both cohorts demonstrated improvements in all clinical outcomes postoperatively, and there was no significant difference between either group in bivariate and multivariate regression analysis of the postoperative clinical outcomes. Twenty patients (35.7%) in the single level ALIF cohort and seven patients (41.2%) in the two-level ALIF groups met the MCID cutoffs in VAS and ODI scores, and there was no significant difference between these patients in outcomes. CONCLUSIONS Both single-level L5-S1 and two-level L4-S1 standalone ALIF for degenerative disc disease demonstrate improvements in all clinical outcomes postoperatively. There is no significant difference between patients who underwent a single-level vs two-level stand-alone ALIF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.