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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 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 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.

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 CONTEXT Pedicle screw fixation can be a major challenge in patients with spinal metastases. The osteopenic nature of the vertebrae along with factors like previous radiation, immunosuppression, and marrow replacement by cancer affect the bone quality for fixation. Complications related to cement augmentation are known. We share our initial experience with the fenestrated screws. PURPOSE To demonstrate the efficacy and safety of this new screw technology in challenged fixation environements, specifically vertebral column metastases. STUDY DESIGN/SETTING Retropsective analysis from a prospective spine oncology database at a major cancer center. PATIENT SAMPLE We identified 38 consecutive patients who underwent posterior thoracic, lumbar, or sacral decompression and stabilization for pathologic fracture or cord compression (T1-sacrum) related to metastatic cancer over a 1 year period. OUTCOME MEASURES Preoperative SINS (spine instability neoplastic score), ASIA grade, cancer histology, radiation history, ECOG, and patient demographics were recorded and analyzed in a multivariable regression analysis. Postoperative CT was performed in all cases. CT was reviewed and cement extravasation was recorded at each level of pedicle screw placement in (1) the epidural space, (2) neural foramen, (3) paravertebral space, (4) lung, and (5) nearby vasculature including the segmental vessels and aorta. Complications and instrumentation or implant failure were recorded. Patient reported outcomes measures were recorded prospectively including EQ-5D, PROMIS-pain, PROMIS-disability, PROMIS-depression, Spine Oncology Study Group Questionnaire. METHODS IRB approval was obtained and a retrospective analysis was performed on a prospective spine oncology outcomes database. Fenestrated screws became available at our institution in November 2016. We identified 38 consecutive patients who underwent posterior thoracic, lumbar, or sacral decompression and stabilization for pathologic fracture or cord compression (T1-sacrum). In each case, postoperative CT imaging was performed within 24 hours of surgery. The investigators independently reviewed the studies evaluating for the extent of cement fill and extravasation. Chart review was performed for analysis of implant or construct failure and complications. RESULTS Thirty eight patients were identified and a total of 292 fenestrated screws were placed with an mean 7.21 screws implanted percase. The most common construct was two levels above and two levels below the site of worst vertebral fracture or cord compression. Cement extravasated into the (1) epidural space at six levels (2.97%), (2) neural foramen at three levels (1.49%), (3) paravertebral space at 37 levels (18.3%), (4) lung – 0, (5) nearby vasculature at 15 levels (7.42%). There was no cement spread to the aorta or vena cava. No patients developed a symptomatic radiculopathy from foraminal extent. No patient required reexploration, cement removal, or hardware revision. Follow-up ranged from 1 month to 15 months with no significant change invertebral body height at the instrumented levels by CT and x-ray. CONCLUSIONS Fenestrated screws with cement provide a safe and effective method for stabilization in the cancer patient.

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.