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Frailty is a common comorbidity associated with worsening outcomes in various medical and surgical fields. The Hospital Frailty Risk Score (HFRS) is a recently developed tool which assesses frailty using 109 International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) comorbidity codes to assess severity of frailty. However, there is a paucity of studies utilizing the HFRS with patients undergoing anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM).The aim of this study was to investigate the impact of HFRS on health care resource utilization following ACDF for CSM.A retrospective cohort study was performed using the Nationwide Inpatient Sample (NIS) database from 2016-2019.All adult (≥18 years old) patients undergoing primary, ACDF for CSM were identified using the ICD-10 CM codes.Weighted patient demographics, comorbidities, perioperative complications, LOS, discharge disposition, and total admission costs were assessed.The 109 ICD-10 codes with pre-assigned values from 0.1 to 7.1 pertaining to frailty were queried in each patient, with a cumulative HFRS ≥5 indicating a frail patient. Patients were then categorized as either Low HFRS (HFRS5) or Moderate to High HFRS (HFRS≥5). A multivariate stepwise logistic regression was used to determine the odds ratio for risk-adjusted extended LOS, non-routine discharge disposition, and increased hospital cost.A total of 29,305 patients were identified, of which 3,135 (10.7%) had a Moderate to High HFRS. Patients with a Moderate to High HFRS had higher rates of 1 or more postoperative complications (Low HFRS: 9.5% vs. Moderate-High HFRS: 38.6%, p≤.001), significantly longer hospital stays (Low HFRS: 1.8±1.7 days vs. Moderate-High HFRS: 4.4 ± 6.0, p≤.001), higher rates of non-routine discharge (Low HFRS: 5.8% vs. Moderate-High HFRS: 28.2%, p≤.001), and increased total cost of admission (Low HFRS: $19,691±9,740 vs. Moderate-High HFRS: $26,935±22,824, p≤.001) than patients in the Low HFRS cohort. On multivariate analysis, Moderate to High HFRS was found to be a significant independent predictor for extended LOS [OR: 3.19, 95% CI: (2.60, 3.91), p≤.001] and non-routine discharge disposition [OR: 3.88, 95% CI: (3.05, 4.95), p≤.001] but not increased cost [OR: 1.10, 95% CI: (0.87, 1.40), p=.418].Our study suggests that patients with a higher HFRS have increased total hospital costs, a longer LOS, higher complication rates, and more frequent nonroutine discharge compared with patients with a low HFRS following elective ACDF for CSM. Although frail patients should not be precluded from surgical management of cervical spine pathology, these findings highlight the need for peri-operative protocols to medically optimize patients to improve health care quality and decrease costs.

Distance learning has become increasingly important to expand access to neurosurgical spine education. However, emerging online spine education initiatives have largely focused on residents, fellows, and surgeons in practice. We aimed to assess the utility of online neurosurgical spine education for medical students regarding career interests, knowledge, and technical skills.A survey assessing the demographics and effects of virtual spine education programming on the interests, knowledge, and technical skills was sent to attendees of several virtual spine lectures. The ratings were quantified using 7-point Likert scales.A total of 36 responses were obtained, of which 15 (41.7%) were from first- or second-year medical students and 18 (50.0%) were from international students. Most respondents were interested in neurosurgery (n = 30; 80.3%), with smaller numbers interested in radiology (n = 3; 8.3%) and orthopedic surgery (n = 2; 5.6%). The rating of utility ranged from 5.69 ± 1.14 to 6.50 ± 0.81 for career, 5.83 ± 0.94 to 6.14 ± 0.80 for knowledge, and 5.22 ± 1.31 to 5.83 ± 1.06 for clinical skills. Of the 36 respondents, 26 (72.2%) preferred virtual neurosurgical spine education via intermixed lectures and interactive sessions. The most common themes regarding the utility of virtual spine education were radiology by 18 (50.0%), anatomy by 12 (33.3%), and case-based teaching by 8 (22.2%) respondents.Virtual distance learning for neurosurgical spine education is beneficial for students by enabling career exploration and learning content and clinical skills. Although the overall benefit was lowest for clinical skills, virtual programming could serve as an adjunct to traditional in-person exposure. Distance learning could also provide an avenue to reduce disparities in medical student neurosurgical spine education locally and globally.

Treatment of spine and sacral chordoma generally involves surgical resection, usually in conjunction with radiation therapy.In certain locations, resection may result in significant neurological dysfunction, so definitive radiation has been used as an alternative to surgery. The purpose of this study is to report the results of high-dose, proton-based definitive radiotherapy for unresected spinal and sacral chordomas.Retrospective review of 67 patients with newly diagnosed, unresected spinal chordomas treated with high-dose definitive, proton-based radiotherapy at our center from 1975 to 2019.Reasons for radiotherapy alone included medical inoperability and/or concern for neurological dysfunction based on spine level or patient choice. Tumor locations included cervical (n = 10), thoracic (n = 1), lumbar (n = 4) spine, and sacrum (n = 52). Median maximal tumor diameter was 7.4 cm (range 1.8-25 cm). Median total dose was 77.4 Gy (RBE) (range 73.8-85.9 Gy RBE). Analysis with median follow-up of 56.2 months (range, 4-171.7 months) showed overall survival of 83.5 % (95%CI: 69.4-91.5%) and 65.9% (95%CI: 47.3-79.3%), disease-free survival of 64% (95%CI: 49.3-75.4) and 44.1% (95%CI: 27.8-59.2%), local control of 81.8% (95%CI: 67.6-90.2%) and 63.6% (95%CI: 44.7-77.5%), and distant control of 77.4% (95%CI: 63.6-86.5%) and 72.5% (95%CI: 55.7-83.8%) at 5 and 8 years respectively. The most common late side effect was insufficiency fracture.These results continue to support the use of high-dose definitive radiotherapy for patients with medically inoperable or otherwise unresected mobile spine or sacrococcygeal chordomas. There is a trend towards better disease-free survival with doses 78 Gy (RBE).

BACKGROUND CONTEXT Frailty has been associated with inferior surgical outcomes in various fields of spinal surgery. With increasing healthcare costs, hospital length of stay (LOS) and unplanned readmissions have emerged as clinical proxies reflecting overall value of care. However, there is a paucity of data assessing the impact that baseline frailty has on quality of care in patients with spondylolisthesis. PURPOSE The aim of this study was to investigate the impact that frailty has on LOS, complication rate, and unplanned readmission after posterior lumbar spinal fusion for spondylolisthesis. STUDY DESIGN A retrospective cohort study was performed using the National Surgical Quality Improvement Program (NSQIP) database from 2010 through 2016. PATIENT SAMPLE All adult (≥18 years old) patients who underwent lumbar spinal decompression and fusion for spondylolisthesis were identified using ICD-9-CM diagnosis and procedural coding systems. We calculated the modified frailty index (mFI) for each patient using 5 dichotomous comorbidities - diabetes mellitus, congestive heart failure, hypertension requiring medication, chronic obstructive pulmonary disease, and dependent functional status. Each comorbidity is assigned 1 point and the points are summed to give a score between 0 and 5. As in previous literature, we defined a score of 0 as “not frail”, 1 as “mild” frailty, and 2 or greater as “moderate to severe” frailty. OUTCOME MEASURES Patient demographics, comorbidities, complications, LOS, readmission, and reoperation were assessed. METHODS A multivariate logistic regression analysis was used to identify independent predictors of adverse events (AEs), extended LOS, complications, and unplanned readmission. RESULTS There were a total of 5,296 patients identified, of which 2,030 (38.3%) were mFI=0, 2,319 (43.8%) patients mFI=1, and 947 (17.9%) were mFI ≥2. The mFI≥2 cohort was older ( p ≤ .001 ) and had a greater average BMI ( p ≤ .001 ). The mFI≥2 cohort had a slightly longer hospital stay (3.7 ± 2.3 days vs. mFI=1: 3.5 ± 2.8 days and mFI=0: 3.2 ± 2.1 days, p ≤ .001 ). Both surgical AEs and medical AEs were significantly greater in the mFI≥2 cohort than the other cohorts, (2.6% vs. mFI=1: 1.8% and mFI=0: 1.2%, p=.022 ) and (6.3% vs. mFI=1: 4.8% and mFI=0: 2.6%, p ≤ .001 ), respectively. While there was no significant difference in reoperation rates, the mFI≥2 cohort had greater unplanned 30-day readmission rates (8;4% vs. mFI=5.6: 4.8% and mFI=0: 3.4%, p ≤ .001 ). However, on multivariate regression analysis, mFI≥2 was not a significant independent predictor of LOS (p=.285), complications (p=.667), or 30-day unplanned readmission (p=.378). CONCLUSIONS Our study indicates that frailty, as measured by the mFI, does not significantly predict LOS, 30-day adverse events, or 30-day unplanned readmission in patients undergoing lumbar spinal decompression and fusion for spondylolisthesis. Further work is needed to better define variable inputs that make up frailty to optimize surgical outcome prediction tools that impact the value of care.

Spinal metastases are an increasing societal health burden secondary to improvements in systemic therapy. Estimates indicate that 100,000 or more people have symptomatic spine metastases requiring management. While open surgery and external beam radiotherapy have been the pillars of treatment, there is growing interest in more minimally invasive technologies (eg separation surgery) and non-operative interventions (eg percutaneous cementoplasty, stereotactic radiosurgery). The great expansion of these alternatives to open surgery and the prevalence of adjuvant therapeutic options means that treatment decision making is now complex and reliant upon multidisciplinary collaboration. To help facilitate construction of care plans that meet patient goals and expectations, clinical decision aids and prognostic scores have been developed. These have been shown to have superior predictive value relative to more classic prediction models and may become an increasingly important aspect of the clinical practice of spinal oncology. Here we overview current therapeutic advances in the management of spine metastases and highlight emerging areas for research. Given the rapid advancements in surgical technologies and adjuvants, the field is likely to undergo further transformative changes in the coming decade.

Objective The aim of this study was to determine if race was an independent predictor of extended length of stay (LOS), nonroutine discharge, and increased health care costs after surgery for spinal intradural/cord tumors. Methods A retrospective cohort study was performed using the National Inpatient Sample database from 2016 to 2017. All adult (>18 years old) inpatients who underwent surgical intervention for a benign or malignant spinal intradural/cord tumor were identified using International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis and procedural coding systems. Patients were then categorized based on race: White, African American (AA), Hispanic, and other. Postoperative complications, LOS, discharge disposition, and total cost of hospitalization were assessed. A backward stepwise multivariable logistic regression analysis was used to identify independent predictors of extended LOS and nonroutine discharge disposition. Results Of 3595 patients identified, there were 2620 (72.9%) whites (W), 310 (8.6%) AAs/blacks, 275 (7.6%) Hispanic (H), and 390 (10.8%) other (O). Postoperative complication rates were similar among the cohorts (P = 0.887). AAs had longer mean (W, 5.4 ± 4.2 days vs. AA, 8.9 ± 9.5 days vs. H, 5.9 ± 3.9 days vs. O, 6.1 ± 3.9 days; P = 0.014) length of hospitalizations than the other cohorts. The overall incidence of nonroutine discharge was 55% (n = 1979), with AA race having the highest rate of nonroutine discharges (W, 53.8% vs. AA, 74.2% vs. H, 45.5% vs. O, 43.6%; P = 0.016). On multivariate regression analysis, AA race was the only significant racial independent predictor of nonroutine discharge disposition (odds ratio, 3.32; confidence interval, 1.67–6.60; P Conclusions Our study indicates that AA race is an independent predictor of nonroutine discharge disposition in patients undergoing surgical intervention for a spinal intradural/cord tumor.

The aim of this study was to compare complication rates, length of stay (LOS), and hospital costs after spine surgery for bony spine tumors and intradural spinal neoplasms.A retrospective cohort study was performed using the National Inpatient Sample database from 2016 to 2017. All adult inpatients who underwent surgical intervention for a primary intradural spinal tumor or primary/metastatic bony spine tumor were identified using International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis/procedural coding systems. Patient demographics, comorbidities, intraoperative variables, complications, LOS, discharge disposition, and total cost of hospitalization were assessed. Backward stepwise multivariable logistic regression analyses were used to identify independent predictors of perioperative complication, extended LOS (≥75th percentile), and increased cost (≥75th percentile).A total of 9855 adult patients were included in the study; 3850 (39.1%) were identified as having a primary intradural spinal tumor and 6005 (60.9%) had a primary or metastatic bony spine tumor. Those treated for bony tumors had more comorbidities (≥3, 67.8% vs. 29.2%) and more commonly experienced ≥1 complications (29.9% vs. 7.9%). Multivariate analyses also showed those in the bony spine cohort had a higher odds of experiencing ≥1 complications (odds ratio [OR], 4.26; 95% confidence interval [CI], 3.04-5.97; P0.001), extended LOS (OR, 2.44; 95% CI, 1.75-3.38; P 0.001), and increased cost (OR, 5.32; 95% CI, 3.67-7.71; P 0.001).Relative to patients being treated for primary intradural tumors, those undergoing spine surgery for bony spine tumors experience significantly higher risk for perioperative complications, extended LOS, and increased cost of hospital admission. Further identification of patient and treatment characteristics that may optimize management of spine oncology may reduce adverse outcomes, improve patient care, and reduce health care resources.

The introduction and integration of robot technology into modern spine surgery provides surgeons with millimeter accuracy for pedicle screw placement. Coupled with computer-based navigation platforms, robot-assisted spine surgery utilizes augmented reality to potentially improve the safety profile of instrumentation.In this study, the authors seek to determine the safety and efficacy of robotic-assisted pedicle screw placement compared to conventional free-hand (FH) technique.We conducted a systematic review of the electronic databases using different MeSH terms from 1980 to 2020.The present study measures pedicle screw accuracy, complication rates, proximal-facet joint violation, intraoperative radiation time, radiation dosage, and length of surgery.A total of 1,525 patients (7,379 pedicle screws) from 19 studies with 777 patients (51.0% with 3,684 pedicle screws) in the robotic-assisted group were included. Perfect pedicle screw accuracy, as categorized by Gerztbein-Robbin Grade A, was significantly superior with robotic-assisted surgery compared to FH-technique (Odds ratio [OR]: 1.68, 95% confidence interval [CI]: 1.20-2.35; p=.003). Similarly, clinically acceptable pedicle screw accuracy (Grade A+B) was significantly higher with robotic-assisted surgery versus FH-technique (OR: 1.54, 95% CI: 1.01-2.37; p=.05). Furthermore, the complication rates and proximal-facet joint violation were 69% (OR: 0.31, 95% CI: 0.20-0.48; p.00001) and 92% less likely (OR: 0.08, 95% CI: 0.03-0.20; p.00001) with robotic-assisted surgery versus FH-group. Robotic-assisted pedicle screw implantation significantly reduced intraoperative radiation time (MD: -5.30, 95% CI: -6.83-3.76; p.00001) and radiation dosage (MD: -3.70, 95% CI: -4.80-2.60; p.00001) compared to the conventional FH-group. However, the length of surgery was significantly higher with robotic-assisted surgery (MD: 22.70, 95% CI: 6.57-38.83; p=.006) compared to the FH-group.This meta-analysis corroborates the accuracy of robot-assisted pedicle screw placement.

Background Context The New England Spinal Metastasis Score (NESMS) was proposed as an intuitive and accessible prognostic tool for predicting survival in patients with spinal metastases. We designed an appropriately powered, prospective, longitudinal investigation to validate the NESMS. Purpose To prospectively validate the NESMS. Study Design Prospective longitudinal observational cohort study. Patient Sample Patients, aged 18 and older, presenting for treatment with spinal metastatic disease. Outcome Measures One-year mortality (primary); 6-month mortality and mortality at any time point following enrollment (secondary). Methods The date of enrollment was set as time zero for all patients. The NESMS was assigned based on data collected at the time of enrollment. Patients were prospectively followed to one of two pre-determined end-points: death, or survival at 365 days following enrollment. Survival was visually assessed with Kaplan-Meier curves and then analyzed using multivariable logistic regression, followed by Bayesian regression to assess for robustness of point estimates and 95% confidence intervals (CI). Results This study included 180 patients enrolled between 2017-2018. Mortality within 1-year occurred in 56% of the cohort. Using NESMS 3 as the referent, those with a score of 2 had significantly greater odds of mortality (OR 7.04; 95% CI 2.47, 20.08), as did those with a score of 1 (OR 31.30; 95% CI 8.82, 111.04). A NESMS score of 0 was associated with perfect prediction, as 100% of individuals with this score were deceased at 1-year. Similar determinations were encountered for our mortality at 6-months and overall. Conclusions This study validates the NESMS and demonstrates its utility in prognosticating survival for patients with spinal metastatic disease, irrespective of selected treatment strategy. This is the first study to prospectively validate a prognostic utility for patients with spinal metastases. The NESMS can be directly applied to patient care, hospital-based practice and healthcare policy.

Background As of May 4, 2020, the coronavirus disease 2019 (COVID-19) pandemic has affected >3.5 million people and touched every inhabited continent. Accordingly, it has stressed health systems worldwide, leading to the cancellation of elective surgical cases and discussions regarding health care resource rationing. It is expected that rationing of surgical resources will continue even after the pandemic peak and may recur with future pandemics, creating a need for a means of triaging patients for emergent and elective spine surgery. Methods Using a modified Delphi technique, a cohort of 16 fellowship-trained spine surgeons from 10 academic medical centers constructed a scoring system for the triage and prioritization of emergent and elective spine surgeries. Three separate rounds of videoconferencing and written correspondence were used to reach a final scoring system. Sixteen test cases were used to optimize the scoring system so that it could categorize cases as requiring emergent, urgent, high-priority elective, or low-priority elective scheduling. Results The devised scoring system included 8 independent components: neurologic status, underlying spine stability, presentation of a high-risk postoperative complication, patient medical comorbidities, expected hospital course, expected discharge disposition, facility resource limitations, and local disease burden. The resultant calculator was deployed as a freely available Web-based calculator ( https://jhuspine3.shinyapps.io/SpineUrgencyCalculator/ ). Conclusions We present the first quantitative urgency scoring system for the triage and prioritizing of spine surgery cases in resource-limited settings. We believe that our scoring system, although not all encompassing, has potential value as a guide for triaging spine surgical cases during the COVID pandemic and post-COVID period.

Background Preoperative prognostication of adverse events (AEs) for patients undergoing surgery for lumbar degenerative spondylolisthesis (LDS) can improve risk stratification and help guide the surgical decision-making process. The aim of this study was to develop and validate a set of predictive variables for 30-day AEs after surgery for LDS. Methods The American College of Surgeons National Surgical Quality Improvement Program was used for this study (2005–2016). Logistic regression (enter, stepwise, and forward) and LASSO (least absolute shrinkage and selection operator) methods were performed to identify and select variables for analyses, which resulted in 26 potential models. The final model was selected based on clinical criteria and numeric results. Results The overall 30-day rate of AEs for 80,610 patients who underwent surgery for LDS in this database was 4.9% (n = 3965). The median age of the cohort was 58.0 years (range, 18–89 years). The model with the following 10-predictive factors (age, gender, American Society of Anesthesiologists grade, autogenous iliac bone graft, instrumented fusion, levels of surgery, surgical approach, functional status, preoperative serum albumin [g/dL] and serum alkaline phosphatase [IU/L]) performed well on the discrimination, calibration, Brier score, and decision analyses to develop machine learning algorithms. Logistic regression showed higher areas under the curve than did LASSO methods across the different models. The predictive probability derived from the best model is uploaded on an open-access Web application, which can be found at: https://spine.massgeneral.org/drupal/Lumbar-Degenerative-AdverseEvents . Conclusions It is feasible to develop machine learning algorithms from large datasets to provide useful tools for patient counseling and surgical risk assessment.

Objective Interbody spacers have been successfully used in spinal fusion procedures with the aim to restore disc height, provide stability, and promote bone fusion. The authors evaluated the efficacy of structural body allograft versus polyetheretherketone (PEEK) implants in patients undergoing spinal fusion surgery. Methods A systematic review of electronic databases was conducted using different Medical Subject Headings terms from January 1970 to August 2019. Pooled and subgroup analyses were performed using random-effects and fixed-effects models based on I2 heterogeneity. Results The analysis included 6640 patients (structural allograft 64% and PEEK cage 36%) from 7 comparative studies. There were no statistically significant differences in age (P = 0.27), sex (P = 0.31), body mass index (P = 0.82), and smoking status (P = 0.27) between the 2 groups. Overall, the mean follow-up was 12.9 ± 1.5 months. Pooled meta-analysis revealed that patients with structural allograft had 2.59-fold higher likelihood of fusion compared with patients with PEEK cages (odds ratio [OR] 2.59, 95% confidence interval [CI] 1.02–6.57, P = 0.05) at last follow-up evaluation. Patients with structural allograft had 61% less likelihood of pseudarthrosis (OR 0.39, 95% CI 0.15–0.98, P = 0.05) and 74% lower incidence of reoperation compared with patients with PEEK implants (OR 0.26, 95% CI 0.09–0.79, P = 0.02). Our results suggest that patients with structural allografts had a higher subsidence rate compared with patients with PEEK implants, but this was statistically insignificant (OR 1.07, 95% CI 0.45–2.53, P = 0.89). Conclusions Our results corroborate that structural allografts are highly effective in promoting bony fusion compared with PEEK implants in patients undergoing spinal fusion surgery.

BACKGROUND CONTEXT There are several prognostic scores available that intend to inform decision-making for patients with spinal metastases. Many of these have not been found to reliably predict survival across the continuum of care. Recently, our group developed the New England Spinal Metastasis Score (NESMS). While the NESMS demonstrated many of the necessary attributes of a useful prediction tool, it has yet to be validated prospectively. PURPOSE To describe the prospective observational study of spinal metastasis treatment (POST). This investigation examined the performance of the NESMS, compared its predictive capacity with other scoring systems and determined its ability to identify patients who benefit the most from surgery. STUDY DESIGN Prospective observational study at two medical centers. PATIENT SAMPLE Patients age 18 and older with spinal metastases involving the spine. OUTCOME MEASURES Survival, post-treatment morbidity and health-related quality of life outcomes. METHODS The POST study assessed patients at baseline and at 1-month, 3-month, 6-month, and 12-month time-points. During the baseline assessment patient demographics, past medical history and assessment of co-morbidities, surgical history, primary tumor histology, and ambulatory status were recorded along with the designated treatment strategy (eg, operative or nonoperative). The NESMS and other predictive scores for each patient were calculated based on baseline data. Study-specific surveys administered at all time-points consisted of the EuroQuol 5-Dimension and Short-Form (SF)-12, Visual Analog Scale (VAS) for pain, and PROMIS assessment of global health. RESULTS Two hundred patients were enrolled in POST from 2017 to 2019. Patients were followed to one of the two predetermined study end-points (ie, mortality, or completion of the 12-month follow-up). Survival was considered the principle dependent variable. Post-treatment morbidity and health-related quality of life outcomes were considered secondarily. Analyses, by aim, relied on Cox proportional hazards regression, repeated measures logistic regression, propensity score matching and multivariable logistic regression. CONCLUSION The POST's findings are anticipated to provide evidence regarding the prognostic capabilities of the NESMS as well as that of other popular grading schemes for survival, post-treatment complications and physical as well as mental function.

BACKGROUND CONTEXT: Laboratory values have been found to be useful predictive measures of survival following surgery. The utility of laboratory values for prognosticating outcomes among patients with spinal metastases has not been studied. PURPOSE: To determine the prognostic capacity of laboratory values at presentation including white blood cell (WBC) count, serum albumin and platelet-lymphocyte ratio (PLR) in patients with spinal metastases. STUDY DESIGN: Retrospective review of records from two tertiary care centers (2005–2017). PATIENT SAMPLE: Patients, aged 40–80, who received operative or non-operative management for spinal metastases. OUTCOME MEASURES: Survival, complications or hospital readmissions within 90 days of treatment and a composite measure for treatment failure accounting for changes in ambulatory function and mortality at 6-months following presentation. METHODS: Multivariable Cox proportional hazard regression analysis was used to analyze the relationship between laboratory values and length of survival, adjusting for confounders. Multivariable logistic regression was used in analyses related to 6-month and 1-year mortality, complications, readmissions and treatment failure. A scoring rubric was developed based on the performance of laboratory values in the multivariable tests. Internal validation was performed using a bootstrap simulation that consisted of sampling with replacement and 1,000 replications. RESULTS: We included 1,216 patients. Thirty-seven percent of patients received a surgical intervention and 63% were treated non-operatively. Median survival for the cohort as a whole was 255 days (inter-quartile range 93–642 days). PLR (HR 1.53; 95% CI 1.29, 1.80; p

In spinal oncology, titanium implants pose several challenges including artifact on advanced imaging and therapeutic radiation perturbation. To mitigate these effects, there has been increased interest in radiolucent carbon fiber (CF) and CF-reinforced polyetheretherketone (CFR-PEEK) implants as an alternative for spinal reconstruction. This study surveyed the members of the North American Spine Society (NASS) section of Spinal Oncology to query their perspectives regarding the clinical utility, current practice patterns, and recommended future directions of radiolucent spinal implants.In February 2021, an anonymous survey was administered to the physicians of the NASS section of Spinal Oncology. Participation in the survey was optional. The survey contained 38 items including demographic questions as well as multiple-choice, yes/no questions, Likert rating scales, and short free-text responses pertaining to the "clinical concept", "efficacy", "problems/complications", "practice pattern", and "future directions" of radiolucent spinal implants.Fifteen responses were received (71.4% response rate). Six of the participants (40%) were neurosurgeons, eight (53.3%) were orthopedic surgeons, and one was a spinal radiation oncologist. Overall, there were mixed opinions among the specialists. While several believed that radiolucent spinal implants provide substantial benefits for the detection of disease recurrence and radiation therapy options, others remained less convinced. Ongoing concerns included high costs, low availability, limited cervical and percutaneous options, and suboptimal screw and rod designs. As such, participants estimated that they currently utilize these implants for 27.3% of anterior and 14.7% of all posterior reconstructions after tumor resection.A survey of the NASS section of Spinal Oncology found a lack of consensus with regards to the imaging and radiation benefits, and several ongoing concerns about currently available options. Therefore, routine utilization of these implants for anterior and posterior spinal reconstructions remains low. Future investigations are warranted to practically validate these devices' theoretical risks and benefits.

BACKGROUND CONTEXT The effectiveness of starting systemic therapies after surgery for spinal metastases from renal cell carcinoma (RCC) has not been evaluated in randomized clinical trials. Agents that target tyrosine kinases, mammalian target of rapamycin signaling, and immune checkpoints are now commonly used. Variables like sarcopenia, nutritional status, and frailty may impact recovery from spine surgery and are considered when evaluating a patient's candidacy for such treatments. Better understanding the significance of these variables may help improve patient selection for available treatment options after surgery. PURPOSE Study the treatment effect of postoperative systemic therapies on survival. STUDY DESIGN/SETTING Observational study using comparative effectiveness methods. PATIENT SAMPLE Adult patients who underwent spine surgery for metastatic renal cell carcinoma (RCC) between 2010-2019 at Massachusetts General Hospital. OUTCOME MEASURES The primary outcome of this study is overall survival. Methods Univariable and multivariable Cox regression analyses were performed to determine factors associated with overall survival (OS) in a retrospective cohort of adult patients who underwent spine surgery for metastatic RCC between 2010-2019. Propensity score matched (PSM) analysis and inversive probability weighting (IPW) were performed to determine the treatment effect of postoperative systemic therapy on OS. To address confounding and minimize bias in estimations, PSM and IPW were adjusted for covariates including age, gender, frailty, sarcopenia, nutrition, visceral metastases, IMDC (International Metastatic RCC Database Consortium) risk score, and performance status. Results Eighty-eight patients (73.9% male; median age, 62 [29-84] years) were identified. Forty-nine of 88 (55.7%) had intermediate IMDC risk and 29 of 88 (33.0%) had poor IMDC risk. Median follow-up was 17 months (1-104 months) during which 57 (64.7%) died. Poor IMDC risk (HR, 3.2, [1.08-9.3]), baseline performance status (ECOG 3-4; HR, 2.7 [1.5-4.7]), and nutrition (prognostic nutritional index 1st tertile; PNI Conclusions This comparative analysis demonstrates that postoperative systemic therapy is associated with improved survival in specific cohorts with metastatic spinal RCC after adjusting for frailty, sarcopenia, and malnutrition. The marked differences in survival should be taken into consideration when planning for surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Background The coronavirus (COVID-19) pandemic effectively ended all major spine educational conferences in the first half of 2020. In response, the authors formed a “virtual” case-based conference series directed at delivering spine education to healthcare providers around the world. We herein share the technical logistics, early participant feedback, and future direction of this initiative. Methods The Virtual Global Spine Conference (VGSC) was created in April 2020 by a multi-institutional team of spinal neurosurgeons and a neuroradiologist. Biweekly virtual meetings were established wherein invited national and international spine care providers would deliver case-based presentations on spine and spine surgery-related conditions via teleconferencing. Promotion was coordinated through social media platforms such as Twitter. Results VGSC recruited over 1000 surgeons, trainees and other specialists, with 50-100 new registrants per week thereafter. An early survey to the participants, with 168 responders, indicated that 92% viewed the content as highly valuable to their practice and 94% would continue participating post-COVID. Participants from the United States (29%), Middle East (16%), and Europe (12%) comprised the majority of the audience. Approximately 52% were neurosurgeons, 18% orthopaedic surgeons, and 6% neuroradiologists. A majority of participants were physicians (55%) and residents/fellows (21%). Conclusion The early success of the VGSC reflects a strong interest in spine education despite the COVID pandemic and social distancing guidelines. There is widespread opinion, backed by our own survey results, that many clinicians and trainees wish to see “virtual” education continue post-COVID., Highlights • The coronavirus pandemic had a detrimental impact on spine education and societal conferences • Teleconferencing platforms have been increasingly used to replace in-person events • Virtual Global Spine Conference was created to deliver spine education during the pandemic • Early survey results demonstrate excellent participant enthusiasm for continued virtual education post-pandemic Abstract

Objectives This study sought to report mechanisms of ventricular tachycardia (VT) and outcomes of VT ablation in patients with a left ventricular assist device (LVAD) as destination therapy. Background Continuous flow LVAD implantation plays a growing role in the management of end-stage heart failure, and VT is common. There are limited reports of VT ablation in patients with a destination LVAD. Methods Patients with a continuous-flow LVAD referred for VT ablation from 2010 to 2016 were analyzed retrospectively. Baseline patient characteristics, procedural data, and clinical follow-up were evaluated. Arrhythmia-free survival was assessed. Results Twenty-one patients (90% male, 62 ± 10 years) underwent catheter ablation of VT at a median of 191 days (interquartile range: 55 to 403 days) after LVAD implantation (15 HeartMate II, 6 HeartWare HVAD). Five patients (24%) had termination (n = 4) or slowing (n = 1) of VT with ablation near the apical inflow cannula, and 3 (14%) had bundle-branch re-entry. Freedom from recurrent VT among surviving patients was 64% at 1 year, with overall survival 67% at 1 year for patients without arrhythmia recurrence and 29% for patients with recurrence (p = 0.049). One patient had suspected pump thrombosis within 30 days of the ablation procedure, with no other major acute complications. Conclusions In this relatively large, single-center experience of VT ablation in destination LVAD, freedom from recurrent VT and implantable cardioverter-defibrillator shocks was associated with improved 1-year survival. Bundle branch re-entry was more prevalent than anticipated, and cannula-adjacent VT was less common. This challenging population remains at risk for late pump thrombosis and mortality.

Summary Bone metastases are devastating complications of cancer. They are particularly common in prostate cancer (PCa), represent incurable disease, and are refractory to immunotherapy. We seek to define distinct features of the bone marrow (BM) microenvironment by analyzing single cells from bone metastatic prostate tumors, involved BM, uninvolved BM, and BM from cancer-free, orthopedic patients, and healthy individuals. Metastatic PCa is associated with multifaceted immune distortion, specifically exhaustion of distinct T cell subsets, appearance of macrophages with states specific to PCa bone metastases. The chemokine CCL20 is notably overexpressed by myeloid cells, as is its cognate CCR6 receptor on T cells. Disruption of the CCL20-CCR6 axis in mice with syngeneic PCa bone metastases restores T cell reactivity and significantly prolongs animal survival. Comparative high-resolution analysis of PCa bone metastases shows a targeted approach for relieving local immunosuppression for therapeutic effect.

Purpose/Objective(s) Radiation-induced lymphocyte depletion has been reported to correlate with survival rate in post-radiotherapy patients with hepatocellular carcinoma. This study aims to assess the impact of integral dose and treatment time on the dose to circulating lymphocytes (CL) with active scanning and passive scattering proton beam therapy (PBS, SOBP), intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Materials/Methods Four plans based on VMAT, IMRT, PBS and SOBP were created for the same hepatocellular carcinoma patient delivering 52.5 Gy in 15 fractions. Six fields, 1 arc, and 2 fields were used for IMRT, VMAT and proton plans, respectively. The dose to CLs after one RT fraction was computed with a novel 4D dynamic blood flow liver model using realistic treatment times (Table 1), which takes into account hepatic vasculature (arterial, portal venous and hepatic venous trees), blood recirculation and time structure of dose delivery. We varied the delivery speed for each modality to achieve total treatment times in the range of 50-250s. The impact of integral dose and treatment time on dose to CLs across different modalities was quantified by the mean dose to CL, the % CL receiving non-zero dose (V0Gy), the % CL receiving > 0.5 Gy dose (V0Gy) and the dose received by highest 2% of CLs (D2%). Results Mean liver dose ranges from 19.4 - 22.2 Gy and treatment time from 60 - 3255s depending on the modality. The PBS and SOBP treatments yield 15% and 10% lower mean dose to CLs compare to VMAT, respectively (Table 1). However, the fraction of lymphocytes receiving any dose varies widely from 37.0% for VMAT to 80.8% for PBS, uncorrelated to integral dose. The fraction of lymphocytes receiving a significant dose (V0.5%) also varies considerably with the highest fraction in VMAT (14.6%) and the lowest for PBS (0.6%). Further analysis indicates that V0Gy depends on both the mean dose and the total treatment time, which explains the large variations observed among various modalities. Every 10s increase in treatment time leads to approximately 3% increase in V0Gy. The opposite trend was found for V0.5Gy and D2%, both decreasing with increasing treatment time. V0.5Gy and D2% decrease approximately 0.6% and 0.01Gy for every 10s increase in treatment time, respectively. Conclusion We studied dose to CLs across 4 different treatment modalities and found that to minimize the fraction of CL irradiated, it might be more important to shorten the delivery time than to reduce the dose bath. Further investigation is required to find the dose levels most correlated to lymphocyte depletion to optimize delivery time and to design immune-sparing RT regimen.

PURPOSE/OBJECTIVE(S) Radiation (RT)-associated lymphopenia may adversely affect treatment outcomes, particularly in the era of immunotherapy. We sought to determine dosimetric factors (DF) correlated with lymphopenia following palliative RT in a cohort of patients with advanced cancer treated with anti-PD-1 immune checkpoint inhibitors (ICIs). MATERIALS/METHODS We included patients with metastatic lung cancer, melanoma, or renal cell carcinoma who were treated with either pembrolizumab or nivolumab and received palliative RT to an extracranial site. Baseline and nadir absolute lymphocyte count (ALC) within 6 weeks of RT were recorded. Heart, lungs, liver, kidneys, spleen, bone, and large blood vessels (LBV) were contoured for each RT course, and various DF were extracted from the corresponding dose-volume histograms (DVHs). To model RT dose to circulating lymphocytes, we also input these DVHs into a whole-body blood flow model that simulates the spatiotemporal distribution of blood particles in organs based on blood volumes and flow rates from ICRP-89. Associations between DF with ALC nadir and ALC change were assessed with Spearman correlation coefficients. DF with the strongest correlations were dichotomized at the median and evaluated for association with grade 3+ lymphopenia (ALC < 500cells/mL) post-RT by univariable logistic regression. RESULTS We analyzed 55 patients who underwent 80 total courses of palliative RT; most (94%) were treated with 3D conformal RT. Doses to whole body, bone, and LBV were negatively correlated with ALC nadir, with the strongest correlations seen at V15 (rs = -0.38, -0.43, and -0.36, P = 0.0004, 0.0001, and 0.001, respectively). Doses to other organs were not significantly correlated with ALC nadir. The modeled dose to circulating lymphocytes was also negatively correlated with ALC nadir and ALC change (for D2%, rs = -0.31 and -0.38, P = 0.005 and 0.0007, respectively). Associations between these DF and grade 3+ lymphopenia are shown in the Table. CONCLUSION RT dose to whole body, bone, and large blood vessels were correlated with lymphopenia in patients treated with palliative RT and anti-PD-1 ICIs. The modeled dose to circulating lymphocytes in our dynamic model correlated with lymphopenia as well, validating our model and enabling future investigation into dose rate and fractionation effects. These dose parameters may help guide RT planning to minimize lymphopenia risk, though additional studies are required to elicit the relative importance of each factor.

BACKGROUND CONTEXT Oncologic resection of primary spine tumors is associated with lower recurrence rates. However, even in the most experienced hands, executing a meticulously drafted plan sometimes fails. PURPOSE The goal of this study was to utilize prospective multicenter data to determine how successful experienced surgical teams are at achieving planned surgical margins and how successful surgeons are in assessing tumor margins intraoperatively. The secondary objective was to identify factors that are associated with successful execution of the planned margins. STUDY DESIGN/SETTING This study was part of a multicenter international prospective registry for the management and outcomes of primary tumors of the spine called Primary Tumor Research and Outcomes Network (PTRON, ClinicalTrials.gov: NCT02790983). PTRON was designed and led by the AO Spine Knowledge Forum Tumor and has established an international network of 16 spine oncology centers from North America, Europe, and Asia that are dedicated to prospective research of patients diagnosed with a primary tumor of the spine. OUTCOME MEASURES Using this registry, we compared (1) planned surgical margin and (2) intraoperative assessment of the margin by the surgeon to the postoperative assessment of the margin by the pathologist. Planned and intraoperative margin assessments by the surgeon were assessed and recorded in the PTRON database in five categories: (1) intralesional; (2) intralesional with planned focal transgression; (3) marginal; (4) wide with marginal at dura, and (5) wide. The pathologist's assessment was documented in four categories for overall margin, at soft tissue, at bone, and at dura: (1) intralesional; (2) intralesional with planned focal transgression; (3) marginal; and (4) wide. The primary endpoints of this analysis were to compare (1) the planned surgical margin and (2) intraoperative assessment of the margin by the surgeon to the postoperative assessment of the margin by the pathologist. For the first endpoint, success was defined as achievement of planned surgical margins or better as confirmed by pathologist assessment. For the second endpoint, success was defined by appropriate intraoperative assessment of the margin by the surgeon when compared to histologic assessment. METHODS Univariate analyses were used to assess factors associated with successful execution of the planned resection. RESULTS A total of 300 patients from 16 centers located in North America, Europe and Asia were included for analysis. Median age was 46.0 years (IQR 27.0 – 61.5). The majority of patients were male (63.0%). Successful achievement of planned margins was attained in 224 patients (74.7%). Overall, marginal or wide margins were attained in 261 patients (87.0%). Surgeon's perception of the margins achieved intraoperatively was correctly determined in 239 patients (79.7%) compared to pathologist assessment. Margins identified as marginal or wide were adequately evaluated intraoperatively as such in 261 patients (87.0%). On univariate analysis, no factors had a statistically significant association with the achievement of successful margins. Conclusions In high volume cancer centers around the world, planned surgical margins can be achieved in approximately 75% of cases. The morbidity of the proposed intervention must be balanced with expected success rates in order to optimize patient management and surgical decision-making. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

General questionnaires are often used to assess quality of life in patients with spine metastases, although a disease-specific survey did not exist until recently. The Spine Oncology Study Group has developed an outcomes questionnaire (SOSG-OQ) to measure quality of life in these patients. However, a scoring system was not developed, and the questionnaire was not validated in a group of patients, nor was it compared with other general quality of life questionnaires such as the EuroQol 5 Dimensions (EQ-5D) questionnaire.Our primary null hypothesis is that there is no association between the SOSG-OQ and EQ-5D. Our secondary null hypothesis is that there is no difference in coverage and internal consistency between the SOSG-OQ and EQ-5D. We also assess coverage, consistency, and validity of the domains within the SOSG-OQ.A survey study from a tertiary care spine referral center was used for this study.The patient sample consisted of 82 patients with spine metastases, myeloma, or lymphoma.The SOSG-OQ (27 questions, 6 domains) score ranges from 0 to 80, with a higher score indicating worse quality of life. The EQ-5D (5 questions, 5 domains) index score ranges from 0 to 1, with a higher score indicating better quality of life.The association between the SOSG-OQ and EQ-5D index score was assessed using the Spearman rank correlation. Instrument coverage and precision were assessed by determining item completion rate, median score with range, and floor and ceiling effect. Internal consistency was assessed using Cronbach alpha. Multitrait analysis and exploratory factor analysis were used to analyze properties of the individual domains in the SOSG-OQ.The Spearman rank correlation between the SOSG-OQ and EQ-5D questionnaire was high (r=-0.83, p.001). Internal consistency of the SOSG-OQ (0.92, 95% CI: 0.89-0.94) was higher as compared to the internal consistency of the EQ-5D (0.73, 95% CI: 0.63-0.84; p.001). The SOSG-OQ score had no floor or ceiling effect indicating good coverage (median 30, range 3-64), whereas the EQ-5D had a ceiling effect of 10% (median 0.71, range 0.05-1).In conclusion, our study proposes a scoring methodology-after reversing four inversely scored items-for the SOSG-OQ and shows that the questionnaire is a valid tool for the assessment of quality of life in patients with metastatic spine disease. The SOSG-OQ is superior to the EQ-5D in terms of coverage and internal consistency but consists of more questions.

BACKGROUND CONTEXT Preoperative prognostication of 30-day mortality in patients with metastatic spine tumors can optimize surgical risk stratification and guide the decision-making process to improve survival. PURPOSE To develop and validate a set of predictive variables of 30-day mortality following surgery for metastatic spine tumors. STUDY DESIGN/SETTING The patient cohort was identified from the American College of Surgeons National Surgical Quality Improvement Program (2005-2016). PATIENT SAMPLE Statistical analysis included 3,566 patients with 30-day mortality in 2.8% (n=100) patients. OUTCOME MEASURES Machine Learning Algorithm METHODS We performed logistic regression (enter, stepwise and forward) and least absolute shrinkage and selection operator (LASSO) method for selection of variables, which resulted in 18-candidate models. The final model was selected based upon clinical knowledge and numerical results. RESULTS The model with 10-predictive factors which included: gender, American Society of Anesthesiologiss Grade, body mass index, location of the tumor, type of surgery, functional health status, chronic obstructive pulmonary disorder, preoperative serum albumin, preoperative hematocrit and preoperative white blood cell count performed best on discrimination, calibration, Brier score and decision analysis to develop a machine learning algorithm. Logistic regression showed higher AUCs than LASSO across these different models. The predictive probability derived from the best model was uploaded on an open access web application which can be found at: https://spine.massgeneral.org/drupal/Mortality-MetastaticSpineTumor CONCLUSIONS Machine learning algorithms show promising results for predicting 30-day mortality following surgery for metastatic spine tumors. These algorithms can be useful aids for counseling patients, assessing pre-operative medical risks, and predicting survival after surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

We report spinal metastasis of adrenal cortical carcinoma (ACC) to the T12 vertebrae with epidural extension. ACC is a rare malignancy with poor prognosis and high rates of metastasis. However, spinal lesions of ACC are rare, and few have been reported in the literature. We discuss our management of this lesion and review the current understanding and treatment of ACC and spinal metastasis.

Objective Intramedullary spinal cord astrocytomas are uncommon but important entities. Aggressive surgical resection is believed to be critical to prevent subsequent neurological deterioration; however, the prognostic significance of numerous patient and molecular variables remains unclear. We sought to investigate the clinical and molecular factors associated with outcomes following surgical resection of adult spinal cord astrocytomas. Methods A consecutive retrospective chart review of all patients who underwent intramedullary spinal cord astrocytoma resection at a single tertiary-care institution between January 1996 and December 2011 was conducted. Molecular data collected included p53 mutation status, proliferative activity (Ki-67), 1p/19q chromosome loss, and EGFR amplification. Multivariable logistic and Cox proportional hazards regression were used to identify variable associated with postoperative outcomes. Results Among 13 patients undergoing surgical resection followed for a median of 54 months, 54% experienced improvement in neurological status, while 15% remained unchanged and 31% deteriorated. Following resection, the 5-year local control (LC), progression-free survival (PFS), and overall survival (OS) rates were 83%, 63%, and 83%. Median PFS time was found to be 5.6 years. Multivariable regression revealed limited characteristics associated with postoperative outcomes, though no molecular characteristics were found to be prognostic. Older age at surgery predicted decreased probability of PFS (HR 0.91, 95% CI 0.81–0.99, p =0.03) and trended towards predicting lack of neurological improvement (OR 0.94, 95% CI 0.83–1.02, p =0.21) and decreased OS (HR 0.93, 95% CI 0.81, 1.03, p =0.15). Preoperative motor symptoms (OR 0.12, 95% CI p =0.14) and adjuvant chemotherapy (OR 0.07, 95% CI p =0.12) also trended towards predicting lack of neurological improvement. Conclusion Age was the only patient variable found to have a statistically significant association with profession-free survival and no other factors were significantly associated with postoperative outcomes. These findings were limited by a relatively small sample size; thus, future studies with increased power investigating the prognostic effects of molecular characteristics could provide further clarity in identifying patients most likely to benefit from surgical resection.

BACKGROUND CONTEXT Anterior cervical discectomy and fusion (ACDF) has been the gold standard surgical treatment for degenerative conditions of the cervical spine, including degenerative disc disease, cervical spondylotic myelopathy, and cervical disc prolapse. This procedure remains the preferred treatment technique particularly for more elderly patients or those with a contraindication to total disc replacement. Multilevel anterior cervical spine fusion with single plates are associated with hardware failure and screw pullout due to stress shielding and excessive loading. Given the lever arm of longer plates and multiple fusion surfaces, pseudarthrosis rates are higher than single level cases. The biomechanics of a new approach using segmental fixation versus convention fixation using a long plate is compared using computational modeling. PURPOSE To compare the biomechanics of multilevel cervical spine fixation using segmental plating versus single plating. STUDY DESIGN/SETTING Computational modeling using cadaver-validated finite element model of cervical spine PATIENT SAMPLE N/A OUTCOME MEASURES Biomechanical data including segmental range of motion and pull-out load on screws METHODS A cadaver-validated finite element (FE) model of C3-C7 spine was used. The model included all crucial anatomical components including, vertebral bones, intervertebral ligaments and connecting tissues, intervertebral disc, facet joints and uncinate processes. The model was validated by comparison of segmental range of motion against data obtained from a cadaver experiment of cervical spine. The validated model was then used to simulate the fixation across C4-C6 using anterior plating, screw and interbody fixation with PEEK cages following simulation of the surgical procedure including total annulectomy and removal of ACL ligaments and the index levels. Two surgical cases were simulated: fixation with two individual plates (each with three screws) vs fixation with single long plate and 6 screws. Anatomical loading of 70N compressive follower load plus 1.5Nm bending moment were applied to the constructs to simulate physiological flexion, extension, lateral bending and axial rotation motions. Segmental motion and screw load data were compared among constructs. RESULTS Fixation at the index levels resulted in significant reduction in range of motion with 60% reduction in extension,85% in left and right axial rotation (LR&RR),63% in left and right lateral bending (LB&RB) and 80% in flexion. The range of motion in the multi-plate construct was similar to the long plate construct in all loadings. At the upper adjacent segment, both constructs yielded a slight increase in ROM in flexion, extension and lateral bending motions (3-10%). The screws in the long plate construct had significantly greater pull out force ranging from 35-82N in extension versus 10-60N in the multi-plate constructs. In axial rotation the ranges of forces were 18-139N in long plate versus 15-70N in multi-plate constructs. The load ranges were similar in both constructs in flexion and lateral bending. CONCLUSIONS Cervical segmental plating allows the ability to treat each level individually yielding in improvement in ability of restoring natural lordosis and biomechanics. When instrumenting across more than one level in ACDF, the individual multi-plates demonstrate superior biomechanics versus the conventional single long plate constructs by ensuring load sharing versus stress shielding. The screw in segmental plating experience lower axial forces resulting in lower risk of screw pull-out post-surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Low fusion rates and cage subsidence have been reported as the main drawbacks of lumbar fixation with stand-alone interbody cages. However, recent new cage placement techniques preserve the spinal structures that contribute to spinal stability. The biomechanical effect of the addition of posterior instrumentation to interbody instrumented segment was evaluated using cadaver spine and validated computational model. PURPOSE To evaluate the mechanical support/stability of different interbody fixation techniques in lumbar spinal segments and the effect of posterior instrumentation support on altering kinematics and load sharing of stand-alone cage instrumented segments. STUDY DESIGN/SETTING A combined cadaveric and finite element (FE) modeling study. PATIENT SAMPLE N/A OUTCOME MEASURES Segmental range of motion and load sharing on vertebral endplate. METHODS An in vitro experiment using seven fresh human cadaveric spines was performed to test intact versus instrumented spines instrumented with stand-alone lateral interbody cages (LIF) and cage instrumented spine supplemented with posterior pedicle screw-rod fixation (360 construct). A Finite element (FE) model of L4-L5 motion segment was also created and validated against cadaveric kinematic data then used to simulate different surgical setting as in the in vitro experiment. The validated model was then used to evaluate the stability of stand-alone lateral (LIF), transforaminal (TLIF) and anterior (ALIF) fixation constructs. The stand-alone cage models were then stabilized with posterior instrumentation and reassessed. To simulate anatomical loading, all FE models of were subjected to a 400N compressive pre-load followed by an 8Nm bending moment. The segmental kinematics and the load sharing at the inferior endplate were computed and compared among cases. RESULTS The segmental ROM for the intact cadaveric segment was 3.1±0.9(Ext), 7.1±2.8(Flex), 5.0±1.7(LB), 5.0±2.1(RB), 2.6±1.8(LR), 2.4±1.7(RR) degrees. The FE model predicted ranges of motion close to the average and within one standard deviation of the cadaver experiment. For the LIF instrumented in vitro cases the motion ranged from 1.7±1.3 (Ext), 1.8±1.0 (Flex), 1.7±1.1 (LB), 1.7±1.0 (RB), 0.9±0.5 (LR), 1.3±0.9 (RR) for cage alone and 0.8±0.5 (Ext), 0.8±0.7 (Flex), 0.9±0.5 (LB), 0.8±0.4 (RB), 0.5±0.4 (LR), 0.6±0.3 (RR) for 360 construct cases. The predicted reduction in motion for ALIF and LIF stand-alone cage cases in axial rotation (AR) and lateral bending (LB) were similar to those with the addition of posterior instrumentation (∼90%). The reduction in sagittal motion for ALIF and LIF ranged from 66% to 86% while the corresponding value for the 360 construct was ∼90%. The peak stresses in extension for the LIF stand-alone cage were somewhat higher than the posterior instrumented cases, but not significant. Stresses for the ALIF cages were similar to the 360 construct designs. Stresses for the ALIF and LIF cages in LB and AR were similar to the posterior instrumented constructs. CONCLUSIONS Our data suggest that stand-alone cages using ALIF and LIF techniques are effective in providing stability primarily in AR and LB, at least under the controlled conditions analyzed in the present study. Clinical data will further define the role and application of stand-alone cages. This data further supports, that 360° stabilization with cage and posterior instrumentation provides maximum construct stability, irrespective of the surgical technique used for cage placement. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Objective We systematically reviewed the literature to compare risk factors for postoperative complications at the surgical wound site in primary and metastatic tumor operations. Methods We screened English-language publications on the outcomes of primary and metastatic spinal tumor operations. Pooled analyses and meta-analyses with random-effects modeling were performed comparing patients with and without wound complications, which were defined as surgical site infection or sterile wound dehiscence. Results Our search identified 5471 unique citations, from which we included 23 studies describing 5104 patients. A total of 1936 patients underwent surgery for primary tumors, with a wound complication rate of 8.1%. Subgroup analysis of benign and malignant primary tumors yielded significantly different wound complication rates of 7.8% and 26.9%, respectively. The metastatic tumor cohort included 168 patients and a complication rate of 6.6%. In a pooled analysis of primary tumors, higher wound complication rates were associated with sacral operations and the use of instrumentation. In the metastatic tumor cohort, higher complication rates were associated with female sex, smoking history, preoperative chemotherapy, preoperative radiotherapy, corticosteroid use, and previous spine surgery. Instrumentation remained a statistically significant risk factor for primary tumors with the addition of random-effects meta-analysis. Conclusions Risk factors for wound complications after primary tumor operations were related to tumor histology and the spinal location of the operation. Risk factors for metastatic tumors may be related to several systemic preoperative treatments and baseline comorbidities. Random-effects meta-analysis showed the limited generalizability of these findings because of the small heterogenous primary literature.

BACKGROUND CONTEXT Renal cell carcinoma (RCC) is one of the most commonly diagnosed malignancies, with an estimated 74,000 new cases in 2019. Approximately 40% of bony metastasis occurs in the spine. Prognostic scoring systems predict the survival time of patients with spinal metastatic disease and guide spine surgeons with decision-making about the best treatment modality. PURPOSE This study aims to assess the performance of previously validated prediction models for spine metastatic disease to predict the survival of RCC patients. STUDY DESIGN/SETTING A multi-centric retrospective study PATIENT SAMPLE Included n=86 patients with spinal metastatic RCC. OUTCOME MEASURES Preoperative scores were calculated using: (1 Tomita, (2 original Tokuhashi, (3 revised Tokuhashi, (4 original Bauer, (5 modified Bauer, (6 Katagiri, (7 Van Der Linden, (8 SORG classic algorithm, (9 SORG nomogram, (10 New England spinal metastasis score (NESMS). METHODS Univariate Cox proportional hazard models were calculated to assess the association of patient variables with 1-year survival. The time-dependent ROC was performed for each model. Cutoffs for (AUC) are as follows: excellent (AUC ≥ 0.90), good (AUC ≥ 0.80 and ˂ 0.90), fair (AUC ≥ 0.70 and ˂ 0.80), and poor performance (AUC ˂ 0.70). RESULTS N=86 patients (60.90±11.36 years, 73.25% male) undergoing spine surgery for spinal metastatic RCC. Univariate analysis showed that patient and tumor factors were strongly associated with 1-year survival: (1 Poor KPS (HR:6.78 [95% CI:1.96–23.48]), (2 ECOG grade 3-4 (HR:3.52 [1.57-7.91]), (3 Frankel grade A-D (HR:2.54 [1.01-6.46]), (4 albumin CONCLUSIONS Most validated prognostic scores have a poor or fair performance in predicting the survival of RCC surgical patients with spinal metastatic disease. Tumor-specific factors and newer treatment modalities affect the survival of RCC patients and should be evaluated in future prognostic studies. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Interbody spacers have been successfully used in spinal fusion procedures with the aim to restore disc height, provide stability and promote the bone fusion. PURPOSE The authors aimed to evaluate the efficacy of structural body allograft vs polyetheretherketone (PEEK) implants in patients undergoing spinal fusion surgery. STUDY DESIGN/SETTING We conducted a systematic review of the electronic databases using different MeSH terms from January 1970 to August 2019. PATIENT SAMPLE A total of 6,640 patients (structural allograft: 64% and PEEK cage: 36%) from 7 comparative studies were included in our analysis. OUTCOME MEASURES Outcome parameters included subsidence rate, mean change in lordotic angle, pseudarthrosis, reoperation, fusion rates and patient reported outcome measures. METHODS Pooled and sub-group analysis were performed using the random and fixed effect model based upon the I2 heterogeneity. RESULTS There was no statistically significant difference in terms of age (p=0.27), gender (p=0.31), body mass index (p=0.82) and smoking status (p=0.27) between the two groups. Overall, the mean follow-up was 12.9 ±1.5 months. Pooled meta-analysis revealed that patients with structural allograft had a 2.59-fold higher likelihood of fusion rates compared to patients with PEEK cages (OR: 2.59, 95% CI:1.02-6.57, p=0.05) at the last follow-up evaluation. Furthermore, patients with structural allograft had 61% less likelihood of pseudarthroses (OR: 0.39, 95%CI: 0.15-0.98, p=0.05) and 74% lower incidence of reoperation compared to patients with PEEK implants (OR:0.26, 95% CI:0.09-0.79, p=0.02). Although our results suggest that patients with structural allografts had a higher subsidence rate compared to PEEK implants, but it was statistically insignificant (OR:1.07, 95% CI: 0.45-2.53, p=0.89). CONCLUSIONS Our results corroborate that structural allografts are highly effective in promoting bony fusion compared to PEEK implants in patients undergoing spinal fusion surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Metabolic syndrome (MetS) is a global epidemic disorder, especially in the Western capitalistic economic development model. PURPOSE To elucidate the predictive ability of the Adult Treatment Panel (ATP)-III for survival and complications in patients who underwent decompressive surgery (DS) for metastatic spinal cord compression (MSCC). STUDY DESIGN/SETTING Patients with MSCC presented at an academic tertiary care hospital from 2011 to 2018 were identified through retrospective chart review. PATIENT SAMPLE Statistical analysis included 119 patients (median age: 67 years; 63% males), with a median survival of 14 months (95%CI: 1-28.2 months, p=0.01). OUTCOME MEASURES Survival and complications following surgery for MSCC. METHODS Patients were categorized into MetS-ATP III (42.9%, n=51) if they met 3 or more of the following criterion: waist circumference (men >102 cm and women >88 cm), triglycerides (≥150 mg/dl), high density cholesterol (men RESULTS All-cause mortality and complications were 62.2% (n=74) and 22.7% (n=27) in our cohort respectively. Patients with MetS-ATP III had a 1.74-fold higher risk of mortality at last follow-up evaluation (HR: 1.74, 95%CI: 1.07-2.81, p=0.02), after adjusting for age, sex, tumor histology and spine instability neoplastic score (SINS). Overall complication rates were significantly higher among patients with MetS (HR: 4.06, 95% CI: 1.68-9.82, p=0.002). Furthermore, the patients with MetS had a higher probability of impaired wound healing (HR: 3.85, 95% CI: 1.57-9.40, p=0.003) and thrombotic disorders (HR: 5.56, 95%CI: 1.63-19.0, p=0.006), adjusted for age, sex, tumor histology and SINS. CONCLUSIONS MetS-ATP III analysis in patients with MSCC who underwent DS was effective in identifying patients at higher risk for shorter survival and more complications. However, further prospective studies are needed to validate our results. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Several surgical techniques for atlantoaxial fixation and arthrodesis have been proposed over the years to treat patients with atlantoaxial instability with the goal of achieving C1-2 fusion. PURPOSE We report a novel C1-2 fixation technique for treating patients with atlantoaxial instability using a loop-suture technique without the use of cables or wires. We propose a safer alternative to securing structural bone graft between C1-2. STUDY DESIGN/SETTING A retrospective review of a prospective database was performed using this technique from 2013-2018 for patients with atlantoaxial instability related to trauma, degeneration, and inflammatory arthropathy. Primary bone and metastatic cancer were excluded. The technique entails anchoring a structural iliac crest autograft or allograft between C1 and C2 for interlaminar arthrodesis in addition to C1 lateral mass and C2 pars/pedicle screw placement. The bone graft is secured using a 0-Prolene suture which is looped under the C1 lamina with the blunt end of the needle first. The needle is then passed through the graft, through the C2-3 interspinous ligaments, and then tied over the graft. We report the utility, safety, durability, and effectiveness of this approach in 32 consecutive patients METHODS A retrospective review of a prospective database was performed using this technique from 2013-2018 for patients with atlantoaxial instability related to trauma, degeneration, and inflammatory arthropathy. Primary bone and metastatic cancer were excluded. The technique entails anchoring a structural iliac crest autograft or allograft between C1 and C2 for interlaminar arthrodesis in addition to C1 lateral mass and C2 pars/pedicle screw placement. The bone graft is secured using a 0-Prolene suture which is looped under the C1 lamina with the blunt end of the needle first. The needle is then passed through the graft, through the C2-3 interspinous ligaments, and then tied over the graft. We report the utility, safety, durability, and effectiveness of this approach in 32 consecutive patients. RESULTS A total of 32 patients were identified who met criteria for atlantoaxial instability due to traumatic dislocation or ligamentous injury (60.0%), cervical spine degeneration (34.5%), deformity (5.25%) or combination of trauma and degeneration (5.25%). The follow-up period ranged from 6 to 24 months (mean 7.8 months). All patients had improvement in their pain by VAS and NDI (85% and 60% improvement respectively, p CONCLUSIONS We demonstrate a novel approach for C1-2 arthrodesis that utilizes a safe technique for securing bone graft without the use of wires or cables, allowing for less sublaminar dissection and potential dural and neurologic injury as well as improved clinical outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Background The purpose of this study was to evaluate the extension of delamination and the cuff integrity after arthroscopic repair of delaminated rotator cuff tears. Methods Sixty-five patients with delaminated rotator cuff tears were retrospectively reviewed. The delaminated tears were divided into full-thickness delaminated tears and partial-thickness delaminated tears. To evaluate the medial extension, we calculated the coronal size of the delaminated portion. To evaluate the posterior extension, we checked the tendon involved. Cuff integrity was evaluated by computed tomography arthrography. Results The mean medial extension in the full-thickness and partial-thickness delaminated tears was 18.1 ± 6.0 mm and 22.7 ± 6.3 mm, respectively ( P = .0084). The posterior extension into the supraspinatus and the infraspinatus was 36.9% and 32.3%, respectively, in the full-thickness delaminated tears, and it was 27.7% and 3.1%, respectively, in the partial-thickness delaminated tears ( P = .0043). With regard to cuff integrity, 35 cases of anatomic healing, 10 cases of partial healing defects, and 17 cases of retear were detected. Among the patients with retear and partial healing of the defect, all the partially healed defects showed delamination. Three retear patients showed delamination, and 14 retear patients did not show delamination; the difference was statistically significant ( P = .0001). Conclusion The full-thickness delaminated tears showed less medial extension and more posterior extension than the partial-thickness delaminated tears. Delamination did not develop in retear patients, but delamination was common in the patients with partially healed defects.

Purpose To evaluate plan quality and delivery efficiency gains of volumetric modulated arc therapy (VMAT) versus a multicriteria optimization-based intensity modulated radiation therapy (MCO-IMRT) for stereotactic radiosurgery of spinal metastases. Methods and materials MCO-IMRT plans (RayStation V2.5; RaySearch Laboratories, Stockholm, Sweden) of 10 spinal radiosurgery cases using 7-9 beams were developed for clinical delivery, and patients were replanned using VMAT with partial arcs. The prescribed dose was 18 Gy, and target coverage was maximized such that the maximum dose to the planning organ-at-risk volume (PRV) of the spinal cord was 10 or 12 Gy. Dose-volume histogram (DVH) constraints from the clinically acceptable MCO-IMRT plans were utilized for VMAT optimization. Plan quality and delivery efficiency with and without collimator rotation for MCO-IMRT and VMAT were compared and analyzed based upon DVH, planning target volume coverage, homogeneity index, conformity number, cord PRV sparing, total monitor units (MU), and delivery time. Results The VMAT plans were capable of matching most DVH constraints from the MCO-IMRT plans. The ranges of MU were 4808-7193 for MCO-IMRT without collimator rotation, 3509-5907 for MCO-IMRT with collimator rotation, 4444-7309 for VMAT without collimator rotation, and 3277-5643 for VMAT with collimator of 90 degrees. The MU for the VMAT plans were similar to their corresponding MCO-IMRT plans, depending upon the complexity of the target and PRV geometries, but had a larger range. The delivery times of the MCO-IMRT and VMAT plans, both with collimator rotation, were 18.3 ± 2.5 minutes and 14.2 ± 2.0 minutes, respectively ( P Conclusions The MCO-IMRT and VMAT can create clinically acceptable plans for spinal radiosurgery. The MU for MCO-IMRT and VMAT can be reduced significantly by utilizing a collimator rotation following the orientation of the spinal cord. Plan quality for VMAT is similar to MCO-IMRT, with similar MU for both modalities. Delivery times can be reduced by nominally 25% with VMAT.

BACKGROUND CONTEXT Increasing prevalence of metastatic disease has been accompanied by increasing rates of surgical intervention. Current tools have poor to fair predictive performance for intermediate (90-day) and long-term (one-year) mortality. PURPOSE The purpose of this study was to develop predictive algorithms for spinal metastatic disease at these time points and to provide patient-specific explanations of the predictions generated by these algorithms. STUDY DESIGN/SETTING Retrospective review was conducted at two large academic medical centers. PATIENT SAMPLE Patients undergoing initial operative management for spinal metastatic disease between January 2000 and December 2016. OUTCOME MEASURES Ninety-day and one-year overall survival. METHODS Five models (penalized logistic regression, random forest, stochastic gradient boosting, neural network, and support vector machine) were developed to predict ninety-day and one-year mortality. RESULTS Overall, 732 patients were identified with ninety-day and one-year mortality rates of 181 (25.1%) and 385 (54.3%), respectively. The stochastic gradient boosting algorithm had the best performance for 90-day mortality and one-year mortality. On global variable importance assessment, albumin, primary tumor histology, and performance status were the three most important predictors of 90-day mortality. The final models were incorporated into an open access web application able to provide predictions as well as patient-specific explanations of the results generated by the algorithms. The application can be found at: https://sorg-apps.shinyapps.io/spinemetssurvival/ CONCLUSIONS Preoperative estimation of 90-day and one-year mortality was achieved with assessment of more flexible modeling techniques such as machine learning. Integration of these models into applications and patient-centered explanations of predictions represent opportunities for incorporation into health care systems as decision tools in the future. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

ional athletes vanced degenaradigm shift tion experts. only an all-orso result from al detrimental nto the media veteran footer of the ball were heavier, after a 5-year tensive degenCTE were disted as cause of y” was docuA concussive episode refers to inertially induced duced traumatic alteration of function of the cere associated imaging abnormalities. Appreciation f of gravity linear acceleration, angular velocity, and eration during dynamic motion of the head a emerged recently in the neurosurgical community literature details potential detrimental effects of r cussive episodes in contact sports such as boxin American football (4, 8, 13-15, 25, 32, 35-37), rug 42), hockey (9, 49, 50), and soccer (18, 23, 24, repeat concussive episode before resolution of init symptoms has been associated with fatal cerebral hypothesized “second impact syndrome” (5, 6, 27 prevention efforts in sports have focused on minim lete’s concussive episode risk, and although the e tive subconcussive trauma in contact sports ha creased attention recently, it has yet to be fully add The term dementia pugilistica (22) describes a syndro sive neurodegeneration, first described in retired box repetitive subconcussive head impacts, that shares logic features with Alzheimer disease (1, 2, 11, 31, 3 term replacing dementia pugilistica, chronic traumati pact-inwithout ad center lar accelrain has luminous itive con, 17, 26), 9, 20, 29, 46-48). A ncussion a via the ain injury g an athof repetieived ined. f progresxposed to icopatho. The new phalopathy which is recognized to result from a variety of minor CTE is associated with personality changes, memor parkinsonism, and speech and gait abnormalities. P marks include gross cerebral andmedial temporal lo extensive tau-immunoreactive neurofibrillary tangle 30, 45). Spurred by highly publicized cases of profess who died at a young age and were found to have ad erative brain changes at autopsy, there has been a p among sports medicine and head injury preven An increasing realization is that brain injury is not nothing phenomenon (eg, concussion) but may al accumulated subconcussive impacts. The potenti effect of repetitive heading in soccer was thrust i limelight in 2002 following the death of English baller Jeffrey Astle. Astle had been a prolific head during an era in which the leather balls employed especially in wet conditions. Astle died at age 59 history of rapidly deterioratingmental capacity. Ex erative brain disease and taupathy consistent with covered at autopsy;minor repetitive traumawas sta death, and a verdict of “death by industrial injur ic entity, mented (28). This ruling of cause of death was especially striking

BACKGROUND CONTEXT The decision for surgical intervention of metastatic lesions of the spine integrates the etiology of pain and neurologic deficits, oncologic history, mechanical instability and systemic disease status. For instance, given the lack of sensitivity to radiation therapy, patients with symptomatic metastatic renal cell cancer (RCC) to the spine are treated with surgical decompression, radiosurgery and medical adjuvant therapies. Modern medical management of metastatic RCC includes therapies targeting growth pathways (PDGFR, mTOR), angiogenesis, and immunotherapy. PURPOSE We hypothesized that patients with spinal RCC metastases would continue to benefit from postoperative initiation of these therapeutics despite presenting with advanced stages of disease. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE We included patients with metastatic renal cell carcinoma involving the spine treated with surgery between 2010 and 2017. The study was approved by the IRB at Massachusetts General Hospital. OUTCOME MEASURES Baseline characteristics were recorded for patients, including ASIA and performance scores, Fuhrman grade, adjuvant therapies, progression free (PFS) and overall survival (OS) following the respective procedures. Preprocedural imaging was reviewed to assign spinal instability neoplastic score (SINS) and epidural spinal cord compression (ESCC) classification. METHODS Kaplan-Meier survival analysis was performed using R statistical software. RESULTS We identified 32 patients with metastatic RCC to the spine treated at MGH between 2010 and 2017 by surgical resection with 72% also receiving postoperative radiosurgery. Instrumented stabilization was performed in 81% of patients for ESCC 2-3 and median preoperative SINS 12. Preoperative embolization was performed in 62% of patients with lower intraoperative blood loss (500±310cc vs. 1000±510cc). Increased progression free (160±91 days vs. 112±50days) and overall survival (913±317 days vs. 466±255 days) following surgery was noted in patients who received postoperative targeted therapies, including inhibitors of PDGFR (100%), VEGF (50%), mTOR (33%) and PD-L1 (11%) initiated at a median of 63 days (28-1254 days) postoperatively. All patients noted postoperative improvement in pain and neurologic function. Postoperative complications included one wound infection and one pulmonary embolus requiring anticoagulation. CONCLUSIONS Postoperative outcomes for metastatic RCC without targeted therapies in this cohort are similar to those reported in earlier series prior to the adoption of these adjuvants. However, we observe a significant increase in survival when modern targeted therapies are administered postoperatively. This has implications on optimizing postoperative multimodal management and also the preoperative evaluation of patients with systemic disease who may have previously been deemed poor surgical candidates. Future analyses of the molecular alterations in metastatic RCC of the spine may further resolve the natural history and predicted treatment response. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Spinal metastases are a major cause of morbidity in patients with cancer. Molecular profiling strategies to characterize lung cancer have identified several genetic biomarkers that may lead to more effective prognostication. PURPOSE The aim of this study was to ascertain whether gene expression signatures in patients with advanced metastatic disease are associated with survival, when the disease has progressed to the spine. PATIENT SAMPLE We identified every consecutive patient at our institution with metastatic lung cancer who underwent surgery for spinal metastases from 2011 to 2017. Inclusion criteria were the availability of genetic mutational data through chart review, and the existence of any known metastatic lesion in the body and spine at the time of presentation. OUTCOME MEASURES Median overall survival (OS) was recorded following both diagnosis and surgical treatment. METHODS Genetic mutations in ALK, MET, ROS1, EGFR, and KRAS were chosen a priori for study based on availability by standard SNaPshot Lung Tumor Genotyping Analysis. Survival time was the duration between treatment for spinal metastases and death. Kaplan-Meier methods and the log-rank test were applied to characterize survival data. RESULTS Twenty-six patients met criteria for inclusion. Median survival following surgery was 0.67 years. Median overall survival (OS) following diagnosis was 2.7 years. The presence of molecular abnormalities in patients with spinal metastases was significantly associated with increased OS(HR 0.38, 95% CI 0.12-1.22, P=.03). CONCLUSIONS Molecular phenotyping may provide prognostic insight in patients undergoing surgery for spinal metastases. This is the first study to demonstrate an association between genetic mutational data and OS in this patient population. It also represents the largest published series of such patients (n=26) for which genetic mutational data are reported. Future models estimating survival for patients with spinal metastases may be enhanced by incorporation of molecular criteria. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.