Development and External Validation of a Risk Calculator for Prediction of Major Complications and Readmission After Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: A retrospective, case-control study. OBJECTIVE: We aim to build a risk calculator predicting major perioperative complications after anterior cervical fusion. In addition, we aim to externally validate this calculator with an institutional cohort of patients who underwent anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: The average age and proportion of patients with at least one comorbidity undergoing ACDF have increased in recent years. Given the increased morbidity and cost associated with perioperative complications and unplanned readmission, accurate risk stratification of patients undergoing ACDF is of great clinical utility. METHODS: This is a retrospective cohort study of adults who underwent anterior cervical fusion at any nonfederal California hospital between 2015 and 2017. The primary outcome was major perioperative complication or 30-day readmission. We built standard and ensemble machine learning models for risk prediction, assessing discrimination, and calibration. The best-performing model was validated on an external cohort comprised of consecutive adult patients who underwent ACDF at our institution between 2013 and 2020. RESULTS: A total of 23,184 patients were included in this study; there were 1886 cases of major complication or readmissions. The ensemble model was well calibrated and demonstrated an area under the receiver operating characteristic curve of 0.728. The variables most important for the ensemble model include male sex, medical comorbidities, history of complications, and teaching hospital status. The ensemble model was evaluated on the validation cohort (n=260) with an area under the receiver operating characteristic curve of 0.802. The ensemble algorithm was used to build a web-based risk calculator. CONCLUSION: We report derivation and external validation of an ensemble algorithm for prediction of major perioperative complications and 30-day readmission after anterior cervical fusion. This model has excellent discrimination and is well calibrated when tested on a contemporaneous external cohort of ACDF cases.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion.

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

Retrospective evaluation of cervical fusion with DTRAX (R) cervical cage.

Background: Cervical radiculopathy is a relatively common problem that often affects individuals in their 5th decade. Most cases resolve with conservative treatment, but when unsuccessful, many opt for surgical intervention. Anterior cervical discectomy and fusion is currently considered the gold standard for the surgical management of cervical radiculopathy. One promising alternative, the DTRAX facet system is minimally invasive and may significantly reduce or eliminate cervical radicular symptoms. This case series and literature review looks to investigate the safety and efficacy of the DTRAX facet system in treating cervical radiculopathy. Methods: This retrospective analysis was performed by chart review of patients who underwent posterior cervical fusion and received the DTRAX spinal implant at University of California, Los Angeles within the last 8 years. Patient charts were located using the surgical cases report function of Epic electronic medical record, and patients were included in the study if they received a DTRAX implant during the stated time period. Data were compiled and analyzed using Microsoft Excel. Results: A total of 14 patient charts were reviewed. Of the 14, there were no immediate postoperative complications. One international patient was subsequently lost to follow-up, and of the remaining 13, mean follow-up duration was 273 days, with a range of 15-660 days. All but one reported improvement of symptoms postoperatively, there were no device failures, and no reoperations were required. There were similar outcomes in patients who received single versus multilevel operations. Conclusion: The findings of this retrospective study of 14 patients who received the DTRAX facet system over the last 8 years support the conclusions of previous studies that DTRAX is safe and effective. In addition, this is the first study to look for differences in outcomes between single and multi-level DTRAX operations, of which there were none. Further investigation with larger cohorts should be conducted as DTRAX becomes more widely adopted in order to verify its safety and efficacy in various clinical scenarios.

Machine learning-driven identification of novel patient factors for prediction of major complications after posterior cervical spinal fusion.

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

Prediction of Major Complications and Readmission After Lumbar Spinal Fusion: A Machine Learning-Driven Approach.

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

Updated external validation of the SORG machine learning algorithms for prediction of ninety-day and one-year mortality after surgery for spinal metastasis.

BACKGROUND CONTEXT: Surgical decompression and stabilization in the setting of spinal metastasis is performed to relieve pain and preserve functional status. These potential benefits must be weighed against the risks of perioperative morbidity and mortality. Accurate prediction of a patient's postoperative survival is a crucial component of patient counseling. PURPOSE: To externally validate the SORG machine learning algorithms for prediction of 90-day and 1-year mortality after surgery for spinal metastasis. STUDY DESIGN/SETTING: Retrospective, cohort study PATIENT SAMPLE: Patients 18 years or older at a tertiary care medical center treated surgically for spinal metastasis OUTCOME MEASURES: Mortality within 90 days of surgery, mortality within 1 year of surgery METHODS: This is a retrospective cohort study of 298 adult patients at a tertiary care medical center treated surgically for spinal metastasis between 2004 and 2020. Baseline characteristics of the validation cohort were compared to the derivation cohort for the SORG algorithms. The following metrics were used to assess the performance of the algorithms: discrimination, calibration, overall model performance, and decision curve analysis. RESULTS: Sixty-one patients died within 90 days of surgery and 133 died within 1 year of surgery. The validation cohort differed significantly from the derivation cohort. The SORG algorithms for 90-day mortality and 1-year mortality performed excellently with respect to discrimination; the algorithm for 1-year mortality was well-calibrated. At both postoperative time points, the SORG algorithms showed greater net benefit than the default strategies of changing management for no patients or for all patients. CONCLUSIONS: With an independent, contemporary, and geographically distinct population, we report successful external validation of SORG algorithms for preoperative risk prediction of 90-day and 1-year mortality after surgery for spinal metastasis. By providing accurate prediction of intermediate and long-term mortality risk, these externally validated algorithms may inform shared decision-making with patients in determining management of spinal metastatic disease.

Utilization trends and outcomes of computer-assisted navigation in spine fusion in the United States.

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

Transoral Removal of an Extruded Odontoid Screw Causing Dysphagia and Dysphonia.

A 77-year-old male underwent open reduction and internal fixation with placement of odontoid screws after sustaining C1 arch and odontoid fractures in a fall 14 months prior to presentation to the laryngology clinic for combined surgery with orthopedics. Serial imaging after the initial surgery demonstrated loosening of a screw and its entry into the pharyngeal lumen. The patient reported odynophagia, dysphagia, and dysphonia. He reported taking small bites and using liquid assist, vocal fatigue, and difficulty with pitch control. A surgical screw entering the pharynx just inferior to the level of the tip of the epiglottis was seen on flexible laryngoscopy. On phonation, the screw made intermittent contact with the right arytenoid resulting in restriction of full abduction of the right vocal fold. On flexible endoscopic evaluation of swallowing, there was pharyngeal and vallecular residue, and residue around the screw itself. The patient was taken to the operating room with orthopedic surgery, the screw was visualized with a combination of mouth gag and endoscopes. It was gently rocked with an orthopedic screw grabber and tapped toward the caudal pharynx. After successful removal, the mucosal defect was sutured. The patient reported improvement in swallowing postoperatively. Dysphagia is a described sequela of cervical spine surgery. We describe the presentation and treatment of a patient with a history of cervical spine surgery and subsequent exposure of an orthopedic screw in the pharynx. Laryngoscope, 131:1078-1080, 2021.

Surgical treatment of metastatic spine disease: an update on national trends and clinical outcomes from 2010 to 2014.

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

Implications of sagittal alignment and complication profile with stand-alone anterior lumbar interbody fusion versus anterior posterior lumbar fusion.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) is commonly utilized in lumbar degenerative pathologies. Standalone ALIF (ST-ALIF) systems were developed to avoid added morbidity, surgical time, and cost of anterior and posterior fusion (APF). Controversy exists in the literature about which of these two techniques yields superior clinical and radiographic outcomes, and few studies have directly compared them. This study seeks to compare ST-ALIF and APF in terms of sagittal correction and surgical complications. METHODS: Ninty-two consecutive ALIF cases performed from 2013-2018 were retrospectively reviewed and separated into 2 groups. Radiographic measurements were performed on pre- and post-operative radiographs, including segmental lordosis (SL), lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL). Surgical complications were determined. Statistical analysis was performed using chi-square test of homogeneity, Fisher's exact test, and independent sample t-test. Comparisons between groups were deemed statistically significant at the P<0.05 threshold. RESULTS: Fifty-seven ST-ALIF, 35 APF were identified. There were no differences in age, gender, BMI, Charlson Comorbidity Index (CCI), preoperative diagnosis, or surgical level between the 2 cohorts. Bone Morphogenetic Protein (BMP) was utilized in 24.6% of ST-ALIF versus none of APF (P=0.001). No differences were detected in SL, LL, and PI-LL mismatch. ST-ALIF cohort had significantly greater risk of subsidence and revision surgery versus APF (12.3% vs. 0%, RD 95% CI: 3.8-20.8%, P=0.042). Recurrent spondylolisthesis occurred in 5 ST-ALIF cases, 3 cases with implant failure, and 2 nonunions versus none in the APF group. CONCLUSIONS: ST-ALIF was associated with significantly greater subsidence and revision surgery versus APF. Careful patient selection is paramount when considering ST-ALIF. The potential for revision surgery may offset the potential benefit in avoiding posterior fusion. Despite the greater risk of subsidence, sagittal alignment was not significantly affected.

Outpatient Posterior Lumbar Fusion: A Population-Based Analysis of Trends and Complication Rates.

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: The aim of this study was to determine the nationwide trends and complication rates associated with outpatient posterior lumbar fusion (PLF). SUMMARY OF BACKGROUND DATA: Outpatient lumbar spine fusion is now possible secondary to minimally invasive techniques that allow for reduced hospital stays and analgesic requirements. Limited data are currently available regarding the clinical outcome of outpatient lumbar fusion. METHODS: The Humana administrative claims database was queried for patients who underwent one to two-level PLF (CPT-22612 or CPT-22633 AND ICD-9-816.2) as either outpatients or inpatients from Q1 2007 to Q2 2015. The incidence of perioperative medical and surgical complications was determined by querying for relevant International Classification of Diseases and Current Procedural Terminology codes. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate odds ratios (ORs) of complications among outpatients relative to inpatients undergoing PLF. RESULTS: Cohorts of 770 patients who underwent outpatient PLF and 26,826 patients who underwent inpatient PLF were identified. The median age was in the 65 to 69 years age group for both cohorts. The annual relative incidence of outpatient PLF remained stable across the study period (R = 0.03, P = 0.646). Adjusting for age, gender, and comorbidities, patients undergoing outpatient PLF had higher likelihood of revision/extension of posterior fusion [(OR 2.33, confidence interval (CI) 2.06-2.63, P < 0.001], anterior fusion (OR 1.64, CI 1.31-2.04, P < 0.001), and decompressive laminectomy (OR 2.01, CI 1.74-2.33, P < 0.001) within 1 year. Risk-adjusted rates of all other postoperative surgical and medical complications were statistically comparable. CONCLUSION: Outpatient lumbar fusion is uncommonly performed in the United States. Data collected from a national private insurance database demonstrate a greater risk of postoperative surgical complications including revision anterior and posterior fusion and decompressive laminectomy. Surgeons should be cautious in performing PLF in the outpatient setting, as the risk of revision surgery may increase in these cases. LEVEL OF EVIDENCE: 3.

Ambulatory anterior cervical discectomy and fusion is associated with a higher risk of revision surgery and perioperative complications: an analysis of a large nationwide database.

BACKGROUND CONTEXT: With the changing landscape of health care, outpatient spine surgery is being more commonly performed to reduce cost and to improve efficiency. Anterior cervical discectomy and fusion (ACDF) is one of the most common spine surgeries performed and demand is expected to increase with an aging population. PURPOSE: The objective of this study was to determine the nationwide trends and relative complication rates associated with outpatient ACDF. STUDY DESIGN/SETTING: This is a large-scale retrospective case control study. PATIENT SAMPLE: The patient sample included Humana-insured patients who underwent one- to two-level ACDF as either outpatients or inpatients from 2011 to 2016 OUTCOME MEASURES: The outcome measures included incidence and the adjusted odds ratio (OR) of postoperative medical and surgical complications within 1 year of the index surgery. MATERIALS AND METHODS: A retrospective review was performed of the PearlDiver Humana insurance records database to identify patients undergoing one- to two-level ACDF (Current Procedural Terminology [CPT]-22551 and International Classification of Diseases [ICD]-9-816.2) as either outpatients or inpatients from 2011 to 2016. The incidence of perioperative medical and surgical complications was determined by querying for relevant ICD and CPT codes. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate ORs of complications among outpatients relative to inpatients undergoing ACDF. RESULTS: Cohorts of 1,215 patients who underwent outpatient ACDF and 10,964 patients who underwent inpatient ACDF were identified. The median age was in the 65-69 age group for both cohorts. The annual relative incidence of outpatient ACDF increased from 0.11 in 2011 to 0.22 in 2016 (R2=0.82, p=.04). Adjusting for age, gender, and comorbidities, patients undergoing outpatient ACDF were more likely to undergo revision surgery for posterior fusion at both 6 months (OR 1.58, confidence interval [CI] 1.27-1.96, p<.001) and 1 year (OR 1.79, CI 1.51-2.13, p<.001) postoperatively. Outpatient ACDF was also associated with a higher likelihood of revision anterior fusion at 1 year postoperatively (OR 1.46, CI 1.26-1.70, p<.001). Among medical complications, postoperative acute renal failure was more frequently associated with outpatient ACDF than inpatient ACDF (OR 1.25, CI 1.06-1.49, p=.010). Adjusted rates of all other queried surgical and medical complications were comparable. CONCLUSIONS: Outpatient ACDF is increasing in frequency nationwide over the past several years. Nationwide data demonstrate a greater risk of perioperative surgical complications, including revision anterior and posterior fusion, as well as a higher risk of postoperative acute renal failure. Candidates for outpatient ACDF should be counseled and carefully selected to reduce these risks.

Chondrosarcoma of the Osseous Spine: An Analysis of Epidemiology, Patient Outcomes, and Prognostic Factors Using the SEER Registry From 1973 to 2012.

STUDY DESIGN: Retrospective analysis. OBJECTIVE: To determine the epidemiology and prognostic indicators in patients with chondrosarcoma of the osseous spine. SUMMARY OF BACKGROUND DATA: Chondrosarcoma of the spine is rare, with limited data on its epidemiology, clinicopathologic features, and treatment outcomes. Therapy centers on complete en bloc resection with radiotherapy reserved for subtotal resection or advanced disease. METHODS: The Surveillance, Epidemiology, and End Results Registry was queried for patients with chondrosarcoma of the osseous spine from 1973 to 2012. Study variables included age, sex, race, year of diagnosis, size, grade, extent of disease, and treatment modality. RESULTS: The search identified 973 cases of spinal chondrosarcoma. Mean age at diagnosis was 51.6 years, and 627% of patients were males. Surgical resection and radiotherapy were performed in 75.2% and 21.3% of cases, respectively. Kaplan-Meier analysis demonstrated overall survival (OS) and disease-specific survival (DSS) of 53% and 64%, respectively, at 5 years. Multivariate Cox regression analysis showed that age (OS, P < 0.001; DSS, P = 0.007), grade (OS, P < 0.001; DSS, P < 0.001), surgical resection (OS, P < 0.001; DSS, P < 0.001), and extent of disease (OS, P < 0.001; DSS, P < 0.001) were independent survival determinants; tumor size was an independent predictor of OS (P = 0.006). For confined disease, age (P = 0.013), decade of diagnosis (P = 0.023), and surgery (P = 0.017) were independent determinants of OS. For locally invasive disease, grade (OS, P < 0.001; DSS, P = 0.003), surgery (OS, P = 0.013; DSS, P = 0.046), and size (OS, P = 0.001, DSS, P = 0.002) were independent determinants of OS and DSS. Radiotherapy was an independent indicator of worse OS for both confined (P = 0.004) and locally invasive disease (P = 0.002). For metastatic disease, grade (OS, P = 0.021; DSS, P = 0.012) and surgery (OS, P = 0.007; DSS, P = 0.004) were survival determinants for both OS and DSS, whereas radiotherapy predicted improved OS (P = 0.039). CONCLUSION: Surgical resection confers survival benefit in patients with chondrosarcoma of the spine independent of extent of disease. Radiotherapy improves survival in patients with metastatic disease and worsens outcomes in patients with confined and locally invasive disease. LEVEL OF EVIDENCE: 4.

Prognostic determinants and treatment outcomes analysis of osteosarcoma and Ewing sarcoma of the spine.

BACKGROUND CONTEXT: Osteosarcoma (OGS) and Ewing sarcoma (EWS) are the two classic primary malignant bone tumors. Due to the rarity of these tumors, evidence on demographics, survival determinants, and treatment outcomes for primary disease of the spine are limited and derived from small case series. PURPOSE: To use population-level data to determine the epidemiology and prognostic indicators in patients with OGS and EWS of the osseous spine. STUDY DESIGN/SETTING: Large-scale retrospective study. PATIENT SAMPLE: Patients diagnosed with OGS and EWS of the spine in the Surveillance, Epidemiology, and End Results (SEER) registry from 1973 to 2012. OUTCOME MEASURES: Overall survival (OS) and disease-specific survival (DSS). METHODS: Two separate queries of the SEER registry were performed to identify patients with OGS and EWS of the osseous spine from 1973-2012. Study variables included age, sex, race, year of diagnosis, tumor size, extent of disease (EOD), and treatment with surgery and/or radiation therapy. Primary outcome was defined as OS and DSS in months. Univariate survival analysis was performed using the Kaplan-Meier method and the log-rank test. Multivariate analysis was performed using Cox proportional hazards regression models. RESULTS: The search identified 648 patients with primary OGS and 736 patients with primary EWS of the spine from 1973 to 2012. Mean age at diagnosis was 48.1 and 19.9 years for OGS and EWS, respectively, with OGS showing a bimodal distribution. The median OS and DSS were 1.3 and 1.7 years, respectively, for OGS, with OGS in Paget's disease having worse OS (0.7 years) relative to the mean (log-rank p=.006). The median OS and DSS for EWS were 3.9 and 4.3 years, respectively. Multivariate cox regression analysis showed that age (OS p<.001, DSS p<.001), decade of diagnosis (OS p=.049), surgical resection (OS p<.001, DSS p<.001), and EOD (OS p<.001, DSS p<.001) were independent positive prognostic indicators for spinal OGS; radiation therapy predicted worse OS (hazard ratio [HR] 1.48, confidence interval [CI] 1.05-2.10, p=.027) and DSS (HR 1.74, CI 1.13-2.66, p=.012) for OGS. For EWS, age (OS p<.001, DSS p<.001), surgical resection (OS p=.030, DSS p=.046), tumor size (OS p<.001, DSS p<.001), and EOD (OS p<.001, DSS p<.001) were independent determinants of improved survival; radiation therapy trended toward improved survival but did not achieve statistical significance for both OS (HR 0.76, CI 0.54-1.07, p=.113) and DSS (0.76, CI 0.54, 1.08, p=.126). CONCLUSIONS: Age, surgical resection, and EOD are key survival determinants for both OGS and EWS of the spine. Radiation therapy may be associated with worse outcomes in patients with OGS, and is of potential benefit in EWS. Overall prognosis has improved in patients with OGS of the spine over the last four decades.

Epidemiology of musculoskeletal injury in the California film and motion picture industry.

INTRODUCTION: Musculoskeletal injury exerts a significant burden on US industry. The purpose of this study was to investigate the frequency and characteristics of musculoskeletal injuries in the California (CA) film and motion picture (FMP) industry which may result in unforeseen morbidity and mortality. METHODS: We reviewed the workers' compensation (WC) claims database of the Workers' Compensation Insurance Rating Bureau of California (WCIRB) and employment statistics through the US Bureau of Labor Statistics (BLS). We analyzed the frequency, type, body part affected, and cause of musculoskeletal injuries. RESULTS: From 2003 to 2009, there were 3505 WC claims of which 94.4% were musculoskeletal. In the CA FMP industry, the most common injuries were strains (38.4%), sprains (12.2%), and fractures (11.7%). The most common sites of isolated injury were the knee (18.9%), lower back (15.0%), and ankle (8.6%). Isolated musculoskeletal spine injuries represented 19.3% of all injuries. The most common causes of injury were work-directed activity (36.0%) and falls (25.5%). CONCLUSION: We present the first report on the unique profile of musculoskeletal injury claims in the FMP industry. This data provides direction for improvement of workplace safety.

Rare case of conus medullaris syndrome from a metastatic yolk sac tumor originating from the mediastinum of an adult male: a case report and review of the literature.

BACKGROUND: Yolk sac tumors (YST) are malignant neoplasms. They are a subtype of germ cell tumors and typically originate in the gonads although extragonadal origins of such tumors have been described. Yolk sac tumors are commonly found in the gonads of infants and children and are extremely rare in adults. The goal of this case report is to describe the clinical presentation of a rare case of metastatic extragonadal yolk sac tumor originating from the mediastinum and causing an acute conus medullaris syndrome in an adult male. METHODS: A 47-year old male presented to our emergency department with a one-day history of bilateral lower extremity weakness, urinary retention and bowel incontinence. Imaging revealed a destructive lesion and a burst fracture of the first lumbar vertebral body (L1) with severe spinal canal stenosis. An urgent spinal decompression and fusion was performed. Oncologic workup revealed a yolk sac tumor originating from the mediastinum. RESULTS: His neurologic function, including motor strength, bowel and bladder function improved in the postoperative period. Chemotherapy regimen of ifosfamide, etoposide and cisplatin was administered and radiation therapy was administered to the spine tumor bed. CONCLUSIONS: Yolk sac tumors, although rare, should be considered in the long list differential diagnosis of an otherwise healthy male presenting with conus medullaris or spinal cord compression from metastatic disease without evidence of a testicular mass. Prompt diagnosis with urgent decompression of neural structures and stabilization of the spine may result in improvement in neurological function.