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Purpose: The objective of our study was to analyze methylomic and clinical features of a cohort of spinal meningiomas (SMs) resected at our institution., Methods: This is a retrospective study of patients undergoing SM resection at our institution between 2010 and 2023. Clinical and radiographic characteristics were reviewed and analyzed with standard statistical methods. A Partitioning Around Medoids approach was used to cluster SMs with methylation data in a combined cohort from our institution and a publicly available dataset by methylation profiles. Clinical variables and pathway analyses were compared for the resulting clusters., Results: Sixty-five SMs were resected in 53 patients with median radiographic follow-up of 34 months. Forty-six (87%) patients were female. The median age at surgery was 65 years and median tumor diameter was 1.9 cm. The five-year progression-free survival rate was 90%, with subtotal resection being associated with recurrence or progression (p = .017). SMs clustered into hypermethylation, intermediate methylation, and hypomethylation subgroups. Tumors in the hypermethylated subgroup were associated with higher WHO grade (p = .046) and higher risk histological subtypes (p <.001), while tumors in the hypomethylated subgroup were least likely to present with copy-number loss in chromosome 22q (p <.0001). SMs classified as immune-enriched under a previously developed intracranial meningioma classifier did not have increased leukocyte fractions or hypomethylation of genes typically hypomethylated in immune-enriched tumors., Conclusion: SMs are more benign than their intracranial counterparts, and gross-total resection results in long term PFS. Methylation profiling identifies subgroups with differences in clinical variables., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background and Objectives: Spinal chordomas are primary bone tumors where surgery remains the primary treatment. However, their low incidence, lack of evidence, and late disease presentation make them challenging to manage. Here, we report the postoperative outcomes of a large cohort of patients after surgical resection, investigate predictors for overall survival (OS) and local recurrence-free survival (LRFS) times, and trend functional outcomes over multiple time periods., Methods: Retrospective review of all patients followed for spinal chordoma at a quaternary spinal oncology center from 2003 to 2023 was included. Data were collected regarding demographics, preoperative and perioperative management, and follow-up since initial definitive surgery. Primary outcomes were OS and LRFS, whereas secondary outcomes were functional deficits., Results: One hundred one patients had an average follow-up of 6.0 ± 4.2 years. At the time of census, 25/101 (24.8%) had experienced a recurrence and 10/101 (9.9%) had died. After surgery, patients experienced a significant decrease in pain over time, but rates of sensory deficits, weakness, and bowel/bladder dysfunction remained static. Tumors ≥100 cm3 (hazard ratio (HR) = 5.89, 95% CI 1.72-20.18, P = .005) and mobile spine chordomas (HR = 7.73, 95% CI 2.09-28.59, P = .002) are related to worse LRFS, whereas having neoadjuvant radiotherapy is associated with improved LRFS (HR = 0.09, 95% CI 0.01-0.88, P = .038). On the other hand, being age ≥65 years was associated with decreased OS (HR = 16.70, 95% CI 1.54-181.28, P = .021)., Conclusion: Surgeons must often weigh the pros and cons of en bloc resection and sacrificing important but affected native tissues. Our findings can provide a benchmark for counseling patients with spinal chordoma. Tumors ≥100 cm3 appear to have a 5.89-times higher risk of recurrence, mobile spine chordomas have a 7.73 times higher risk, and neoadjuvant radiotherapy confers an 11.1 times lower risk for local recurrence. Patients age ≥65 years at surgery have a 16.70 times higher risk of mortality than those <65 years., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and "platybasia," noting that these terms are often used interchangeably but represent distinct entities. We then provide examples that represent these pathologies and treatment paradigms. Finally, we discuss the challenges and future direction in the craniovertebral junction surgery space., (Copyright © 2023. Published by Elsevier Inc.)

The craniovertebral junction (CVJ), or the "first junction," can be affected by a variety of pathological states. Some of these conditions could represent a gray area in that they can be treated by general neurosurgeons or such specialists as skull base or spinal surgeons. However, some conditions are best managed with a multidisciplinary approach. The importance of in-depth knowledge of the anatomy and biomechanics of this junction cannot be overemphasized. Identifying what represents clinical stability or instability is key to successful diagnosis and, hence, treatment. In this report, the second in a 3-article series, we describe our approach to managing CVJ pathologies in a case-based fashion to illustrate key concepts., (Copyright © 2023. Published by Elsevier Inc.)

Von Hippel-Lindau (VHL) disease is a tumor predisposition syndrome caused by mutations in the VHL gene that presents with visceral neoplasms and growths, including clear cell renal cell carcinoma, and central nervous system manifestations, such as hemangioblastomas of the brain and spine. The pathophysiology involves dysregulation of oxygen sensing caused by the inability to degrade HIFα, leading to the overactivation of hypoxic pathways. Hemangioblastomas are the most common tumors in patients with VHL and cause significant morbidity. Until recently, there were no systemic therapies available for patients that could effectively reduce the size of these lesions. Belzutifan, the first approved HIF-2α inhibitor, has demonstrated benefit in VHL-associated tumors, with a 30% response rate in hemangioblastomas and ~30%-50% reduction in their sizes over the course of treatment. Anemia is the most prominent adverse effect, affecting 76%-90% of participants and sometimes requiring dose reduction or transfusion. Other significant adverse events include hypoxia and fatigue. Overall, belzutifan is well tolerated; however, long-term data on dosing regimens, safety, and fertility are not yet available. Belzutifan holds promise for the treatment of neurological manifestations of VHL and its utility may influence the clinical management paradigms for this patient population., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Study Design: Retrospective cohort study., Objective: The aim was to investigate the accuracy of pedicle screw placement by freehand technique and to compare revision surgery rates among three different imaging verification pathways., Summary of Background Data: Studies comparing different imaging modalities in freehand screw placement surgery are limited., Materials and Methods: A single-institution retrospective chart review identified adult patients who underwent freehand pedicle screw placement in the thoracic, lumbar or sacral levels. Patients were stratified into three cohorts based on the intraoperative imaging modality used to assess the accuracy of screw position: intraoperative X-rays (cohort 1); intraoperative O-arm (cohort 2); or intraoperative computed tomography (CT)-scan (cohort 3). Postoperative CT scans were performed on all patients in cohorts 1 and 2. Postoperative CT scan was not required in cohort 3. Screw accuracy was assessed using the Gertzbein-Robbins grading system., Results: A total of 9179 pedicle screws were placed in the thoracic or lumbosacral spine in 1311 patients. 210 (2.3%) screws were identified as Gertzbein-Robbins grades C-E on intraoperative/postoperative CT scan, 137 thoracic screws, and 73 lumbar screws ( P <0.001). Four hundred and nine patients underwent placement of 2754 screws followed by intraoperative X-ray (cohort 1); 793 patients underwent placement of 5587 screws followed by intraoperative O-arm (cohort 2); and 109 patients underwent placement of 838 screws followed by intraoperative CT scan (cohort 3). Postoperative CT scans identified 65 (2.4%) and 127 (2.3%) malpositioned screws in cohorts 1 and 2, respectively. Eleven screws (0.12%) were significantly malpositioned and required a second operation for screw revision. Nine patients (0.69%) required revision operations: eight of these patients were from cohort 1 and one patient was from cohort 2., Conclusion: When compared to intraoperative X-ray, intraoperative O-arm verification decreased the revision surgery rate for malpositioned screws from 0.37% to 0.02%. In addition, our analysis suggests that the use of intraoperative O-arm can obviate the need for postoperative CT scans., Competing Interests: A.B. has a consultation agreement with NuVasive spine. D.M.S. has consultation agreements with Depuy-Synthes, Medtronic, Stryker, Baxter, Augmedics. T.W. has the following disclosures: Medical Advisory Board and Investor-Augmedics, Inc., Grant support for spinal Fusion research from The Gordon and Marilyn Macklin Foundation, Stock Owner-Additive/Addivation Orthopedics. N.T. reports receiving royalties and consulting fees from Globus Medical and royalties from Depuy-Synthes. The remaining authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Metastatic spinal tumors commonly arise from primary breast cancer. We assessed outcomes and identified associated variables for patients who underwent surgical management for spinal metastases of breast cancer., Methods: We retrospectively reviewed patients surgically treated for spinal metastases of breast cancer. Neurologic and functional outcomes were analyzed via Frankel scale and Karnofksy Performance Status (KPS) scores, respectively. Variables associated with Frankel and KPS scores after surgery were identified. Multivariable analysis was used to assess predictors for postoperative survival., Results: Forty-nine patients were identified. There was no significant difference in Frankel scores postoperatively and at last follow-up. KPS scores (P = 0.002) significantly improved at last follow-up. Preoperative non-ambulation and postprocedural complications were associated with non-ambulation postoperatively. Postprocedural complications and disease-free interval (DFI) &lt; 24 and &lt; 60 months were associated with functional impairment at last follow-up. Current smoking status at the time of surgery (P = 0.021) and triple negative (negative immunohistochemistry for estrogen receptor, progesterone receptor, and HER2) breast cancer (P = 0.038) were significantly associated with shortened postoperative survival., Conclusion: When indicated, surgery for spinal metastases of breast cancer leads to preservation of neurologic status and long-term functional improvement. Preoperative ambulatory status and postprocedural complications were associated with ambulatory status after surgery, while postprocedural complications and shortened DFI were associated with functional status after surgery.Current smoking status at the time of surgery and triple negative breast cancer are negative predictors for postoperative survival after metastatic breast cancer to the spine., (Copyright © 2022. Published by Elsevier B.V.)

Background Context: Intramedullary spinal cord tumors (IMSCTs) are rare tumors associated with significant morbidity and mortality. Surgical resection is often indicated for symptomatic lesions but may result in new neurological deficits and decrease quality of life. Identifying predictors of these adverse outcomes may help target interventions designed to reduce their occurrence. Nonetheless, most prior studies have employed population-level datasets with limited granularity., Purpose: To determine independent predictors of nonroutine discharge, prolonged length of stay (LOS), and 30 day readmission and reoperation, and to deploy these results as a web-based calculator., Study Design: Retrospective cohort study PATIENT SAMPLE: A total of 235 patients who underwent resection of IMSCTs at a single comprehensive cancer center., Outcome Measures: Nonroutine discharge, prolonged LOS, 30 day readmission, and 30 day reoperation METHODS: Patients who underwent surgery from June 2002 to May 2020 at a single tertiary center were included. Data was collected on patient demographics, clinical presentation, tumor histology, surgical procedures, and 30 day readmission and reoperation. Functional status was assessed using the Modified McCormick Scale (MMS) and queried preoperative neurological symptoms included weakness, urinary and bowel dysfunction, numbness, and back and radicular pain. Variables significant on univariable analysis at the α≤0.15 level were entered into a stepwise multivariable logistic regression model., Results: Of 235 included cases, 131 (56%) experienced a nonhome discharge and 68 (29%) experienced a prolonged LOS. Of 178 patients with ≥ 30 days of follow-up, 17 (9.6%) were readmitted within 30 days and 13 (7.4%) underwent reoperation. Wound dehiscence (29%) was the most common reason for readmission. Nonhome discharge was independently predicted by older age (OR=1.03/year; p<.01), thoracic location of the tumor (OR=2.36; p=.01), presenting with bowel dysfunction (OR=4.09; p=.03), and longer incision length (OR=1.44 per level; p=.03). Independent predictors of prolonged LOS included presenting with urinary incontinence (OR=2.65; p=.05) or a higher preoperative white blood cell count (OR=1.08 per 10 3 /μL); p=.01), while GTR predicted shorter LOS (OR=0.40; p=.02). Independent predictive factors for 30 day unplanned readmission included experiencing ≥1 complications during the first hospitalization (OR=6.13; p<.01) and having a poor (A-C) versus good (D-E) baseline neurological status on the ASIA impairment scale (OR=0.23; p=.03). The only independent predictor of unplanned 30 day reoperation was experiencing ≥1 inpatient complications during the index hospitalization (OR=6.92; p<.01). Receiver operating curves for the constructed models produced C-statistics of 0.67-0.77 and the models were deployed as freely available web-based calculators (https://jhuspine5.shinyapps.io/Intramedullary30day)., Conclusions: We found that neurological presentation, patient demographics, and incision length were important predictors of adverse perioperative outcomes in patients with IMSCTs. The calculators can be used by clinicians for risk stratification, preoperative counseling, and targeted interventions., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: Surgical resection is considered standard of care for primary intramedullary astrocytomas, but the infiltrative nature of these lesions often precludes complete resection without causing new post-operative neurologic deficits. Radiotherapy and chemotherapy serve as potential adjuvants, but high-quality data evaluating their efficacy are limited. Here we analyze the experience at a single comprehensive cancer center to identify independent predictors of postoperative overall and progression-free survival., Methods: Data was collected on patient demographics, tumor characteristics, pre-operative presentation, resection extent, long-term survival, and tumor progression/recurrence. Kaplan-Meier curves modeled overall and progression-free survival. Univariable and multivariable accelerated failure time regressions were used to compute time ratios (TR) to determine predictors of survival., Results: 94 patients were included, of which 58 (62%) were alive at last follow-up. On multivariable analysis, older age (TR = 0.98; p = 0.03), higher tumor grade (TR = 0.12; p < 0.01), preoperative back pain (TR = 0.45; p < 0.01), biopsy [vs GTR] (TR = 0.18; p = 0.02), and chemotherapy (TR = 0.34; p = 0.02) were significantly associated with poorer survival. Higher tumor grade (TR = 0.34; p = 0.02) and preoperative bowel dysfunction (TR = 0.31; p = 0.02) were significant predictors of shorter time to detection of tumor growth., Conclusion: Tumor grade and chemotherapy were associated with poorer survival and progression-free survival. Chemotherapy regimens were highly heterogeneous, and randomized trials are needed to determine if any optimal regimens exist. Additionally, GTR was associated with improved survival, and patients should be counseled about the benefits and risks of resection extent., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms whose treatment is often technically challenging. Given the low volume seen at most centers, perioperative outcomes have been reported infrequently. Here, the authors present the largest single-institution series of IMSCTs, focusing on the clinical presentation, histological makeup, perioperative outcomes, and long-term survival of surgically treated patients., Methods: A cohort of patients operated on for primary IMSCTs at a comprehensive cancer center between June 2002 and May 2020 was retrospectively identified. Data on patient demographics, tumor histology, neuraxial location, baseline neurological status, functional deficits, and operative characteristics were collected. Perioperative outcomes of interest included length of stay, postoperative complications, readmission, reoperation, and discharge disposition. Data were compared across tumor histologies using the Kruskal-Wallis H test, chi-square test, and Fisher exact test. Pairwise comparisons were conducted using Tukey's honest significant difference test, chi-square test, and Fisher exact test. Long-term survival was assessed across tumor categories and histological subtype using the log-rank test., Results: Three hundred two patients were included in the study (mean age 34.9 ± 19 years, 77% white, 57% male). The most common tumors were ependymomas (47%), astrocytomas (31%), and hemangioblastomas (11%). Ependymomas and hemangioblastomas disproportionately localized to the cervical cord (54% and 59%, respectively), whereas astrocytomas were distributed almost equally between the cervical cord (36%) and thoracic cord (38%). Clinical presentation, extent of functional dependence, and postoperative 30-day outcomes were largely independent of underlying tumor pathology, although tumors of the thoracic cord had worse American Spinal Injury Association (ASIA) grades than cervical tumors. Rates of gross-total resection were lower for astrocytomas than for ependymomas (54% vs 84%, p < 0.01) and hemangioblastomas (54% vs 100%, p < 0.01). Additionally, 30-day readmission rates were significantly higher for astrocytomas than ependymomas (14% vs 6%, p = 0.02). Overall survival was significantly affected by the underlying pathology, with astrocytomas having poorer associated prognoses (40% at 15 years) than ependymomas (81%) and hemangioblastomas (66%; p < 0.01) and patients with high-grade ependymomas and astrocytomas having poorer long-term survival than those with low-grade lesions (p < 0.01)., Conclusions: The neuraxial location of IMSCTs, extent of resection, and postoperative survival differed significantly across tumor pathologies. However, perioperative outcomes did not vary significantly across tumor cohorts, suggesting that operative details, rather than pathology, may have a stronger influence on the short-term clinical course, whereas pathology appears to have a stronger impact on long-term survival.

Objective: Treatment of primary spinal infection includes medical management with or without surgical intervention. The objective of this study was to identify risk factors for the eventual need for surgery in patients with primary spinal infection on initial presentation., Methods: From January 2010 to July 2019, 275 patients presented with primary spinal infection. Demographic, infectious, imaging, laboratory, treatment, and outcome data were retrospectively reviewed and collected. Thirty-three patients were excluded due to insufficient follow-up (≤ 90 days) or death prior to surgery., Results: The mean age of the 242 patients was 58.8 ± 13.6 years. The majority of the patients were male (n = 130, 53.7%), White (n = 150, 62.0%), and never smokers (n = 132, 54.5%). Fifty-four patients (22.3%) were intravenous drug users. One hundred fifty-four patients (63.6%) ultimately required surgery while 88 (36.4%) never needed surgery during the duration of follow-up. There was no significant difference in age, gender, race, BMI, or comorbidities between the surgery and no-surgery groups. On univariate analysis, the presence of an epidural abscess (55.7% in the no-surgery group vs 82.5% in the surgery group, p < 0.0001), the median spinal levels involved (2 [interquartile range (IQR) 2-3] in the no-surgery group vs 3 [IQR 2-5] in the surgery group, p < 0.0001), and active bacteremia (20.5% in the no-surgery vs 35.1% in the surgery group, p = 0.02) were significantly different. The cultured organism and initial laboratory values (erythrocyte sedimentation rate, C-reactive protein, white blood cell count, creatinine, and albumin) were not significantly different between the groups. On multivariable analysis, the final model included epidural abscess, cervical or thoracic spine involvement, and number of involved levels. After adjusting for other variables, epidural abscess (odds ratio [OR] 3.04, 95% confidence interval [CI] 1.64-5.63), cervical or thoracic spine involvement (OR 2.03, 95% CI 1.15-3.61), and increasing number of involved levels (OR 1.16, 95% CI 1.01-1.35) were associated with greater odds of surgery. Fifty-two surgical patients (33.8%) underwent decompression alone while 102 (66.2%) underwent decompression with fusion. Of those who underwent decompression alone, 2 (3.8%) of 52 required subsequent fusion due to kyphosis. No patient required hardware removal due to persistent infection., Conclusions: At time of initial presentation of primary spinal infection, the presence of epidural abscess, cervical or thoracic spine involvement, as well as an increasing number of involved spinal levels were potential risk factors for the eventual need for surgery in this study. Additional studies are needed to assess for risk factors for surgery and antibiotic treatment failure.

Study Design: This was a cross-sectional study., Objective: The objective of this study is to report the impact of COVID-19 on spine surgery fellow education and readiness for practice., Summary of Background Data: COVID-19 has emerged as one of the most devastating global health crises of our time. To minimize transmission risk and to ensure availability of health resources, many hospitals have cancelled elective surgeries. There may be unintended consequences of this decision on the education and preparedness of current surgical trainees., Materials and Methods: A multidimensional survey was created and distributed to all current AO Spine fellows and fellowship directors across the United States and Canada., Results: Forty-five spine surgery fellows and 25 fellowship directors completed the survey. 62.2% of fellows reported >50% decrease in overall case volume since cancellation of elective surgeries. Mean hours worked per week decreased by 56.2%. Fellows reported completing a mean of 188.4±64.8 cases before the COVID-19 crisis and 84.1% expect at least an 11%-25% reduction in case volume compared with previous spine fellows. In all, 95.5% of fellows did not expect COVID-19 to impact their ability to complete fellowship. Only 2 directors were concerned about their fellows successfully completing fellowship; however, 32% of directors reported hearing concerns regarding preparedness from their fellows and 25% of fellows were concerned about job opportunities., Conclusions: COVID-19 has universally impacted work hours and case volume for spine surgery fellows set to complete fellowship in the middle of 2020. Nevertheless, spine surgery fellows generally feel ready to enter practice and are supported by the confidence of their fellowship directors. The survey highlights a number of opportunities for improvement and innovation in the future training of spine surgeons., Level of Evidence: Level III., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Chordomas are the most common primary spinal column malignancy in the United States. The aim of this study was to determine whether chordomas may be detected by evaluating mutations in circulating tumor DNA (ctDNA)., Methods: Thirty-two patients with a biopsy-confirmed diagnosis of chordoma had blood drawn pre-operatively and/or at follow-up appointments. Mutations in the primary tumor were identified by whole exome sequencing and liquid biopsy by ddPCR and/or RACE-Seq was used to detect one or more of these mutations in plasma ctDNA at concurrent or later time points., Results: At the time of initial blood draw, 87.1% of patients were ctDNA positive ( P < .001). Follow-up blood draws in twenty of the patients suggest that ctDNA levels may reflect the clinical status of the disease. Patients with positive ctDNA levels were more likely to have greater mutant allele frequencies in their primary tumors ( P = .004) and undergo radiotherapy ( P = .02), and the presence of ctDNA may correlate with response to systemic chemotherapy and/or disease recurrence., Conclusions: Detection of ctDNA mutations may allow for the detection and monitoring of disease progression for chordomas., (© The Author(s) 2020. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Objective: Myelopathy selectively involving the lower extremities can occur secondary to spondylotic changes, tumor, vascular malformations, or thoracolumbar cord ischemia. Vascular causes of myelopathy are rarely described. An uncommon etiology within this category is diaphragmatic crus syndrome, in which compression of an intersegmental artery supplying the cord leads to myelopathy. The authors present the operative technique for treating this syndrome, describing their experience with 3 patients treated for acute-onset lower-extremity myelopathy secondary to hypoperfusion of the anterior spinal artery., Methods: All patients had compression of a lumbar intersegmental artery supplying the cord; the compression was caused by the diaphragmatic crus. Compression of the intersegmental artery was probably producing the patients' symptoms by decreasing blood flow through the artery of Adamkiewicz, causing lumbosacral ischemia., Results: All patients underwent surgery to transect the offending diaphragmatic crus. Each patient experienced substantial symptom improvement, and 2 patients made a full neurological recovery before discharge., Conclusions: Diaphragmatic crus syndrome is a rare or under-recognized cause of ischemic myelopathy. Patients present with episodic acute-on-chronic lower-extremity paraparesis, gait instability, and numbness. Angiography confirms compression of an intersegmental artery that gives rise to a dominant radiculomedullary artery. Transecting the offending diaphragmatic crus can produce complete resolution of neurological symptoms.

Spine surgery has evolved from the advent of imaging and navigation guidance, particularly with the rise of robotic surgical assistance. Navigation guidance has demonstrated potential for increased accuracy of transpedicular screw placement and resecting primary and metastatic spinal tumors. Robotic surgery is widely accepted in other surgical fields because laparoscopic techniques applied to robots can increase operator dexterity and improve visualization. Robotic assistance with spinal tumors has enjoyed rising interest owing to the potential for safe and minimally traumatic resection. We discuss available robots used for navigation-guided transpedicular screw placement and state-of-the-art robotic techniques for spinal or paraspinal tumor resection., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms that have limited treatment options and are associated with high rates of morbidity and mortality. To better understand the genetic basis of these tumors we performed whole exome sequencing on 45 tumors and matched germline DNA, including twenty-nine spinal cord ependymomas and sixteen astrocytomas. Though recurrent somatic mutations in IMSCTs were rare, we identified NF2 mutations in 15.7% of tumors (ependymoma, N = 7; astrocytoma, N = 1), RP1 mutations in 5.9% of tumors (ependymoma, N = 3), and ESX1 mutations in 5.9% of tumors (ependymoma, N = 3). We further identified copy number amplifications in CTU1 in 25% of myxopapillary ependymomas. Given the paucity of somatic driver mutations, we further performed whole-genome sequencing of 12 tumors (ependymoma, N = 9; astrocytoma, N = 3). Overall, we observed that IMSCTs with intracranial histologic counterparts (e.g. glioblastoma) did not harbor the canonical mutations associated with their intracranial counterparts. Our findings suggest that the origin of IMSCTs may be distinct from tumors arising within other compartments of the central nervous system and provides the framework to begin more biologically based therapeutic strategies.

Background: Spinal chordomas, a subtype of primary spinal column malignancies (PSCM), are rare tumors with poor prognosis, and we have limited understanding of the molecular drivers of neoplasia., Methods: Study design was a retrospective review of prospectively collected data with cross-sectional survival. Archived paraffin embedded pathologic specimens were collected for 133 patients from 6 centers within Europe and North America between 1987 and 2012. Tumor DNA was extracted and the human telomerase reverse transcriptase (hTERT) promoter was sequenced. The hTERT mutational status was correlated with overall survival (OS) and time to first local recurrence., Results: Ninety-two chordomas, 26 chondrosarcomas, 7 osteosarcomas, 3 Ewing's sarcomas, and 5 other malignant spinal tumors were analyzed. Median OS following surgery was 5.8 years (95% CI: 4.6 to 6.9) and median time to first local recurrence was 3.9 years (95% CI: 2.5 to 6.7). Eight chordomas, 2 chondrosarcomas, 1 Ewing's sarcoma, and 1 other malignant spinal tumor harbored either a C228T or C250T mutation in the hTERT promoter. In the overall cohort, all patients with hTERT mutation were alive at 10 years postoperative with a median OS of 5.1 years (95% CI: 4.5 to 6.6) (P = 0.03). hTERT promoter mutation was observed in 8.7% of spinal chordomas, and 100% of chordoma patients harboring the mutation were alive at 10 years postoperative compared with 67% patients without the mutation (P = 0.05)., Conclusions: We report for the first time that hTERT promoter mutations C228T and C250T are present in approximately 8.7% of spinal chordomas. The presence of hTERT mutations conferred a survival benefit and could potentially be a valuable positive prognostic molecular marker in spinal chordomas., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)

Study Design: This is a retrospective study., Objective: To report the safety profile of S2-alar-iliac (S2AI) in patients over 60, comparing S2AI screws with iliac screws (ISs)., Summary of Background Data: The surgical management involving the lumbosacropelvic spine remains a challenge due to high mechanical demand and risk of pseudarthrosis. Previous articles showed lower rates of complications in patients receiving S2AI screws than ISs; however, none of them have focused on patients aged over 60 who may harbor significant comorbidities and thus require more meticulous perioperative management, given these invasive and lengthy procedures., Materials and Methods: Retrospective review of clinical records from 2010 to 2015 identified 60 patients undergoing lumbosacropelvic fixation (17 patients with ISs and 43 patients with S2AI screws) who satisfied the following criteria: (1) patients aged over 60 years old and (2) patients with >1-year follow-up periods. Rates of complications such as unplanned reoperation and cardiorespiratory complications were collected and statistically analyzed., Results: Baseline characteristics such as age, sex, and comorbidities were similar in both groups. The S2AI group had lower rates of reoperation (18.6% vs. 47.4%; P=0.02), surgical site infection (2.3% vs. 29.4%; P=0.006), wound dehiscence (2.3% vs. 29.4%; P=0.006), and postoperative anemia (7.0% vs. 29.4%; P=0.03) and had lower total volume of estimated blood loss (EBL) (mL) (1846.4 vs. 2721.2; P=0.02) and transfused red blood cell units (7.2 vs. 4.7; P=0.04) than the IS group, while rates of L5-S1 pseudarthrosis and other cardiorespiratory complications were similar in both groups. In multivariate analysis, operative time, body mass index, and use of S2AI screws over ISs were independent predictors of EBL., Conclusions: Use of S2AI screws over ISs in patients aged over 60 was associated with lower rates of reoperation, surgical site infection, wound dehiscence, and lower volume of EBL and red blood cell transfusion and is a viable surgical option.

Background: Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases-without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility., Methods: We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed., Results: The average age of the 69 patients was 60.8 ± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5-23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed., Conclusions: Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: With the advent of intraoperative electrophysiological neuromonitoring (IONM), surgical outcomes of various neurosurgical pathologies, such as brain tumors and spinal deformities, have improved. However, its diagnostic and therapeutic value in resecting intradural extramedullary (ID-EM) spinal tumors has not been well documented in the literature. The objective of this study was to summarize the clinical results of IONM in patients with ID-EM spinal tumors., Methods: A retrospective patient database review identified 103 patients with ID-EM spinal tumors who underwent tumor resection with IONM (motor evoked potentials, somatosensory evoked potentials, and free-running electromyography) from January 2010 to December 2015. Patients were classified as those without any new neurological deficits at the 6-month follow-up (group A; n = 86) and those with new deficits (group B; n = 17). Baseline characteristics, clinical outcomes, and IONM findings were collected and statistically analyzed. In addition, a meta-analysis in compliance with the PRISMA guidelines was performed to estimate the overall pooled diagnostic accuracy of IONM in ID-EM spinal tumor resection., Results: No intergroup differences were discovered between the groups regarding baseline characteristics and operative data. In multivariate analysis, significant IONM changes (p < 0.001) and tumor location (thoracic vs others, p = 0.018) were associated with new neurological deficits at the 6-month follow-up. In predicting these changes, IONM yielded a sensitivity of 82.4% (14/17), specificity of 90.7% (78/86), positive predictive value (PPV) of 63.6% (14/22), negative predictive value (NPV) of 96.3% (78/81), and area under the curve (AUC) of 0.893. The diagnostic value slightly decreased in patients with schwannomas (AUC = 0.875) and thoracic tumors (AUC = 0.842). Among 81 patients who did not demonstrate significant IONM changes at the end of surgery, 19 patients (23.5%) exhibited temporary intraoperative exacerbation of IONM signals, which were recovered by interruption of surgical maneuvers; none of these patients developed new neurological deficits postoperatively. Including the present study, 5 articles encompassing 323 patients were eligible for this meta-analysis, and the overall pooled diagnostic value of IONM was a sensitivity of 77.9%, a specificity of 91.1%, PPV of 56.7%, and NPV of 95.7%., Conclusions: IONM for the resection of ID-EM spinal tumors is a reasonable modality to predict new postoperative neurological deficits at the 6-month follow-up. Future prospective studies are warranted to further elucidate its diagnostic and therapeutic utility.

Background: Robotic-assisted techniques have been implemented in the surgical treatment of tumors in the pelvis, abdomen, and thorax. In pelvic tumors, robotic-assisted techniques evade the need for sizable surgical exposure, but make stimulation of the nerves of the sacral plexus very difficult., Objective: To describe how laparoscopic robotic-assisted surgery can couple with tools such as the nerve stimulator to aid in the resection of presacral masses emanating from the neural elements and potentially improve neurological outcome by preventing inadvertent injury to involved nerves., Methods: A patient with a large presacral ganglioneuroma underwent resection using the DaVinci system (Intuitive Surgical, Sunnyvale, California) for robotic assistance. A nerve stimulator was coupled to the bipolar cautery instrument of the DaVinci robot to define the presence of functional nerves in the surroundings of the tumor., Results: By coupling a nerve stimulator to the bipolar cautery instrument of the DaVinci robot (Intuitive Surgical), it was possible to identify important neural structures in close proximity to the tumor. After identifying functional nerves, the surgeon was able to preserve them and preserve neurological function avoiding motor dysfunction., Conclusion: The use of a nerve stimulator coupled to the bipolar cautery instrument of the DaVinci robot (Intuitive Surgical) during laparoscopic, robotic-assisted surgery for resection of presacral masses is safe and feasible. In addition to the preoperative evaluation, intraoperative monitoring and stimulation of nerves in close proximity to the tumor and also exiting through neural foramina involved by the tumor allowed the surgeon to understand the anatomy and preserve neurological function while obtaining optimal surgical resection.

Recent work has yielded a method for automatic labeling of vertebrae in intraoperative radiographs as an assistant to manual level counting. The method, called LevelCheck, previously demonstrated promise in phantom studies and retrospective studies. This study aims to: (#1) Analyze the effect of LevelCheck on accuracy and confidence of localization in two modes: (a) Independent Check (labels displayed after the surgeon's decision) and (b) Active Assistant (labels presented before the surgeon's decision). (#2) Assess the feasibility and utility of LevelCheck in the operating room. Two studies were conducted: a laboratory study investigating these two workflow implementations in a simulated operating environment with 5 surgeons, reviewing 62 cases selected from a dataset of radiographs exhibiting a challenge to vertebral localization; and a clinical study involving 20 patients undergoing spine surgery. In Study #1, the median localization error without assistance was 30.4% (IQR = 5.2%) due to the challenging nature of the cases. LevelCheck reduced the median error to 2.4% for both the Independent Check and Active Assistant modes (p < 0.01). Surgeons found LevelCheck to increase confidence in 91% of cases. Study #2 demonstrated accuracy in all cases. The algorithm runtime varied from 17 to 72 s in its current implementation. The algorithm was shown to be feasible, accurate, and to improve confidence during surgery.

Background: Surgical treatment of severe cervicothoracic kyphotic deformity may require the use of 3-column osteotomies such as the pedicle subtraction osteotomy and vertebral column resection (VCR), or VCR with anterior longitudinal ligament resection. Such procedures are extensive and are associated with high intra- and perioperative morbidity, in part, due to the need for risky reduction maneuvers., Objective: To describe a novel technique utilizing a laterally placed articulating hinge to facilitate kyphotic deformity correction of the cervicothoracic spine., Methods: A patient with severe chin-on-chest deformity of the cervicothoracic spine presented for evaluation and a 2-stage VCR with anterior longitudinal ligament resection was planned. To reduce the risk of intraoperative neurological injury and for increased control during reduction maneuvers, lateral instrumentation was placed through the chest wall resection above and below the level of VCR, which was adjoined with an articulating hinge rod apparatus., Results: Satisfactory reduction of the kyphosis was achieved utilizing the hinge rod apparatus for controlled deformity correction. The patient remained neurologically intact following this procedure with improvement in their spinal alignment., Conclusion: We present a novel technique utilizing a lateral hinge rod apparatus for efficient, controlled correction of severe kyphotic deformity.

Resection of a giant pre-sacral schwannoma originating from the right S2 nerve in a 22-year-old woman illustrates the potential for robotic surgery. The da Vinci Robot Surgical System facilitates visualization deep in the pelvis and allows for bimanual wristed instrument control to dissect the tumor from surrounding sensitive structures. Neurostimulation to identify critical nerves is possible and complete resection of the tumor can be achieved. There were no complications, she remained neurologically intact, the estimated blood loss was less than 75 ml, the total hospital stay was 3 days, and she returned to work within 2 weeks of her operation. In select patients, robot-assisted surgery may have advantages. The video can be found here: https://youtu.be/SYjUA-WcyGI .

OBJECTIVE Resection of metastatic spine tumors can improve patients' quality of life by addressing pain or neurological compromise. However, resections are often complicated by wound dehiscence, infection, instrumentation failures, and the need for reoperation. Moreover, when reoperations are needed, the most common indication is surgical site infection and wound breakdown. In turn, wound reoperations increase morbidity as well as the length and cost of hospitalization. The aim of this study was to examine perioperative risk factors associated with increased rate of wound reoperations after metastatic spine tumor resection. METHODS A retrospective study of patients at a single institution who underwent metastatic spine tumor resection between 2003 and 2013 was conducted. Factors with a p value < 0.200 in a univariate analysis were included in the multivariate model. RESULTS A total of 159 patients were included in this study. Karnofsky Performance Scale score > 70, smoking status, hypertension, thromboembolic events, hyperlipidemia, increasing number of vertebral levels, and posterior approach were included in the multivariate analysis. Thromboembolic events (95% CI 1.19-48.5, p = 0.032) and number of levels involved were independently associated with increased wound reoperation rates in the multivariate model. For each additional spinal level involved, the risk for wound reoperations increased by 21% (95% CI 1.03-1.43, p = 0.018). CONCLUSIONS Although wound complications and subsequent reoperations are potential risks for all patients with metastatic spine tumor, due to adjuvant radiotherapy and other medical comorbidities, this study identified patients with thromboembolic events or those requiring a larger incision as being at the highest risk. Measures intended to decrease the occurrence of perioperative venous thromboembolism and to improve wound care, especially for long incisions, may decrease wound-related revision surgeries in this vulnerable group of patients.

Percutaneous pelvic screw placement is challenging due to narrow bone corridors surrounded by vulnerable structures and difficult visual interpretation of complex anatomical shapes in 2D x-ray projection images. To address these challenges, a system for planning, guidance, and quality assurance (QA) is presented, providing functionality analogous to surgical navigation, but based on robust 3D-2D image registration techniques using fluoroscopy images already acquired in routine workflow. Two novel aspects of the system are investigated: automatic planning of pelvic screw trajectories and the ability to account for deformation of surgical devices (K-wire deflection). Atlas-based registration is used to calculate a patient-specific plan of screw trajectories in preoperative CT. 3D-2D registration aligns the patient to CT within the projective geometry of intraoperative fluoroscopy. Deformable known-component registration (dKC-Reg) localizes the surgical device, and the combination of plan and device location is used to provide guidance and QA. A leave-one-out analysis evaluated the accuracy of automatic planning, and a cadaver experiment compared the accuracy of dKC-Reg to rigid approaches (e.g. optical tracking). Surgical plans conformed within the bone cortex by 3-4 mm for the narrowest corridor (superior pubic ramus) and  >5 mm for the widest corridor (tear drop). The dKC-Reg algorithm localized the K-wire tip within 1.1 mm and 1.4° and was consistently more accurate than rigid-body tracking (errors up to 9 mm). The system was shown to automatically compute reliable screw trajectories and accurately localize deformed surgical devices (K-wires). Such capability could improve guidance and QA in orthopaedic surgery, where workflow is impeded by manual planning, conventional tool trackers add complexity and cost, rigid tool assumptions are often inaccurate, and qualitative interpretation of complex anatomy from 2D projections is prone to trial-and-error with extended fluoroscopy time.

Study Design: Retrospective cohort study., Objective: The S2-alar-iliac (S2AI) technique has been described as an alternative method for pelvic fixation in place of iliac screws (ISs) in spinal deformity surgery. The objective of this study was to analyze the impact of S2AI screws on radiographical outcomes, including spinopelvic parameters., Methods: A retrospective review of 17 patients receiving ISs and 46 patients receiving S2AI screws for correction of adult spinal deformity between 2010 and 2015 with minimum 1-year follow-up was conducted. Patient data on postoperative complications, including reoperation rates and proximal junctional kyphosis (PJK), and radiographical parameters was collected and statistically analyzed., Results: With mean follow-up of 21.1 months, the overall reoperation rate was significantly lower in the S2AI group than in the IS group (21.7% vs 58.8%, P = .01), but the incidence of PJK was similar (32.6% vs 35.3%, P > .99). Moreover, the time to reoperation in the IS group was significantly shorter than in the S2AI group ( P = .001), and the S2AI group trended toward a longer time to reoperation due to PJK ( P = .08). There was a significantly higher change in pelvic incidence (PI) in the S2AI group (-6.0°) compared with the IS group ( P = .001)., Conclusions: Compared with the IS technique, the S2AI technique demonstrated a lower rate of overall reoperation, a similar rate of PJK, longer time to reoperation, and possible reduction in PI. Future studies may be warranted to clarify the mechanism of these results and how they can be translated into improved patient care., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Author CRG is a UNCF-Merck Postdoctoral Fellow and is supported by an award from the Burroughs Wellcome Fund. Author AB received a research grant from DePuy Synthes Spine and serves on the clinical advisory board of MedImmune, LLC. Author ZLG has stock ownership in US Spine and Spinal Kinetics, consulting, speaking, and teaching agreements for the AO Foundation, and research support from DePuy Synthes, NREF, AOSpine and AO North America. Author DMS received honoraria from Depuy Synthes, and has had consulting agreements with Medtronic, Globus, Stryker, and Orthofix. Author TFW receives research support from the Gordon and Marilyn Macklin Foundation, and has received complementary research medications from Eli Lilly and Company.

Background and Purpose: The early diagnosis of spinal vascular malformations suffers from the nonspecificity of their clinical and radiologic presentations. Spinal angiography requires a methodical approach to offer a high diagnostic yield. The prospect of false-negative studies is particularly distressing when addressing conditions with a narrow therapeutic window. The purpose of this study was to identify factors leading to missed findings or inadequate studies in patients with spinal vascular malformations., Materials and Methods: The clinical records, laboratory findings, and imaging features of 18 patients with spinal arteriovenous fistulas and at least 1 prior angiogram read as normal were reviewed. The clinical status was evaluated before and after treatment by using the Aminoff-Logue Disability Scale., Results: Eighteen patients with 19 lesions underwent a total of 30 negative spinal angiograms. The lesions included 9 epidural arteriovenous fistulas, 8 dural arteriovenous fistulas, and 2 perimedullary arteriovenous fistulas. Seventeen patients underwent endovascular (11) or surgical (6) treatment, with a delay ranging between 1 week and 32 months; the Aminoff-Logue score improved in 13 (76.5%). The following factors were identified as the causes of the inadequate results: 1) lesion angiographically documented but not identified (55.6%); 2) region of interest not documented (29.6%); or 3) level investigated but injection technically inadequate (14.8%)., Conclusions: All the angiograms falsely reported as normal were caused by correctible, operator-dependent factors. The nonrecognition of documented lesions was the most common cause of error. The potential for false-negative studies should be reduced by the adoption of rigorous technical and training standards and by second opinion reviews., (© 2017 by American Journal of Neuroradiology.)

A multi-stage image-based 3D-2D registration method is presented that maps annotations in a 3D image (e.g. point labels annotating individual vertebrae in preoperative CT) to an intraoperative radiograph in which the patient has undergone non-rigid anatomical deformation due to changes in patient positioning or due to the intervention itself. The proposed method (termed msLevelCheck) extends a previous rigid registration solution (LevelCheck) to provide an accurate mapping of vertebral labels in the presence of spinal deformation. The method employs a multi-stage series of rigid 3D-2D registrations performed on sets of automatically determined and increasingly localized sub-images, with the final stage achieving a rigid mapping for each label to yield a locally rigid yet globally deformable solution. The method was evaluated first in a phantom study in which a CT image of the spine was acquired followed by a series of 7 mobile radiographs with increasing degree of deformation applied. Second, the method was validated using a clinical data set of patients exhibiting strong spinal deformation during thoracolumbar spine surgery. Registration accuracy was assessed using projection distance error (PDE) and failure rate (PDE  >  20 mm-i.e. label registered outside vertebra). The msLevelCheck method was able to register all vertebrae accurately for all cases of deformation in the phantom study, improving the maximum PDE of the rigid method from 22.4 mm to 3.9 mm. The clinical study demonstrated the feasibility of the approach in real patient data by accurately registering all vertebral labels in each case, eliminating all instances of failure encountered in the conventional rigid method. The multi-stage approach demonstrated accurate mapping of vertebral labels in the presence of strong spinal deformation. The msLevelCheck method maintains other advantageous aspects of the original LevelCheck method (e.g. compatibility with standard clinical workflow, large capture range, and robustness against mismatch in image content) and extends capability to cases exhibiting strong changes in spinal curvature.

Background: Cerebral intraoperative DSA (IODSA) is a well-described, routinely performed procedure that allows the effectiveness of cerebrovascular interventions to be evaluated in the operating room. Spinal IODSA, on the other hand, is infrequently obtained and has received less attention., Objective: To discuss the indications, technique, safety, and clinical impact of spinal IODSA., Materials and Methods: Twenty-three patients underwent 45 thoracic and/or lumbar spinal IODSA between 2005 and 2016, either immediately before surgery for lesion localization or after the intervention to evaluate its effectiveness. Indications included 21 vascular malformations and 2 diaphragmatic crus compression syndromes. A long femoral arterial sheath with its hub positioned on the lateral surface of the thigh was used to allow catheter manipulations in the prone position., Results: All targeted intersegmental arteries (ISAs) were successfully catheterized. The course of surgery was changed in 6 instances (26.1%). In 4 cases of epidural or perimedullary arteriovenous fistulae (AVFs), a residual lesion required additional intervention. In one case of epidural AVF, initial IODSA revealed spontaneous resolution of the lesion, preventing unnecessary surgery. Finally, angiography performed in a case of diaphragmatic crus syndrome showed thrombosis of the ISA and non-visualization of the artery of Adamkiewicz. Recanalization was obtained by IA thrombolysis, with excellent clinical outcome. No intraprocedural or postprocedural complication was noted., Conclusions: Spinal IODSA is a safe technique that offers an immediate assessment of the effectiveness of a spinovascular surgical procedure, notably epidural and perimedullary AVFs. Spinal IODSA was technically successful in all cases, influencing the surgical strategy in 6 of 23 patients, including one patient who benefited from intraoperative endovascular therapy., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Background: Surgical management of spinal metastasis is complex and can be associated with significant postoperative morbidity. Analyzing readmission rates may serve as a proxy for postoperative morbidity and functional decline, allowing patients and physicians to make informed decisions about treatment., Methods: Retrospective analysis was performed of patients with metastatic spine disease surgically treated at a tertiary center from 2003 to 2012. Patients with primary lung cancer, breast cancer, kidney cancer, bone marrow cancer, prostate cancer, gynecologic cancer, and melanoma were analyzed. Primary and secondary outcome variables were readmissions and overall survival. Multivariate Cox proportional hazards model was used to identify independent factors associated with readmissions., Results: There were 159 patients analyzed. Lung, breast, and kidney represented the most common primary cancer sites, accounting for 22%, 19.5%, and 16.4%. Of patients, 56.6% had at least 1 readmission, with a 30-day readmission rate of 13.8% and 1-year readmission rate of 47.2%. Readmissions were for surgical complications (26.7%), oncologic disease progression (33.7%), and other medical reasons (36.7%). Patients with colorectal cancer had the highest number of readmissions. Patients with melanoma had more readmissions over the course of their limited postoperative survival. Overall mortality was 59.1%, with a median survival of 15.1 months. Multivariate analysis revealed age >60 years and previous radiation of the spine increased the likelihood of readmission., Conclusions: Readmissions provide an important window into understanding postoperative morbidity among patients with metastatic disease of the spine. This study offers an important starting point for understanding the nuances of patients' postoperative outcomes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: Systematic review., Objectives: We conducted a systematic review of the literature to answer the following questions regarding the use of steroid therapy in metastatic spinal cord compression (MSCC): 1. In cases of MSCC, what is the effect of steroid administration before definitive radiotherapy or surgery on ambulatory status, bowel and bladder function and survival? 2. What steroid dosing regimens are associated with the best outcomes concerning neurological symptoms and complication prevention in cases of MSCC?, Summary of Background Data: Currently, there is significant variation in the initial bolus dose, daily maintenance dose and duration of treatment when steroids are used as a bridge to definitive therapy for MSCC., Methods: A literature search following PRISMA guidelines was conducted in June 2016, using Medline via Ovid SP, Medline via PubMed, Embase, Biosis Previews and the Cochrane Library. Search terms used in each database varied slightly to optimize results. All generic steroid formulations were included along with spinal cord compression or myelopathy combined with metastatic or malignant tumors. Papers discussing acute traumatic causes of spinal cord compression were excluded, as were papers discussing cord compression from nonmetastatic tumors or epidural lipomatosis. Subjects were limited to adult humans undergoing definitive treatment with radiotherapy or surgery., Results: Of the 309 papers retrieved, 66 full text studies were reviewed and 6 papers were found to address the stated questions., Conclusions: There is a paucity of high quality literature evaluating the use of steroids in MSCC. On the basis of the evidence available an initial 10 mg intravenous bolus of dexamethasone followed by 16 mg PO QD has been associated with fewer complications compared with 100 mg bolus and 96 mg QD. Weaning of steroids should occur rapidly after definitive treatment. Risk of gastric bleeding or perforation can be managed with the routine use of proton-pump inhibitors., Level of Evidence: Level IIIa.

Intraoperative x-ray radiography/fluoroscopy is commonly used to assess the placement of surgical devices in the operating room (e.g. spine pedicle screws), but qualitative interpretation can fail to reliably detect suboptimal delivery and/or breach of adjacent critical structures. We present a 3D-2D image registration method wherein intraoperative radiographs are leveraged in combination with prior knowledge of the patient and surgical components for quantitative assessment of device placement and more rigorous quality assurance (QA) of the surgical product. The algorithm is based on known-component registration (KC-Reg) in which patient-specific preoperative CT and parametric component models are used. The registration performs optimization of gradient similarity, removes the need for offline geometric calibration of the C-arm, and simultaneously solves for multiple component bodies, thereby allowing QA in a single step (e.g. spinal construct with 4-20 screws). Performance was tested in a spine phantom, and first clinical results are reported for QA of transpedicle screws delivered in a patient undergoing thoracolumbar spine surgery. Simultaneous registration of ten pedicle screws (five contralateral pairs) demonstrated mean target registration error (TRE) of 1.1  ±  0.1 mm at the screw tip and 0.7  ±  0.4° in angulation when a prior geometric calibration was used. The calibration-free formulation, with the aid of component collision constraints, achieved TRE of 1.4  ±  0.6 mm. In all cases, a statistically significant improvement (p  <  0.05) was observed for the simultaneous solutions in comparison to previously reported sequential solution of individual components. Initial application in clinical data in spine surgery demonstrated TRE of 2.7  ±  2.6 mm and 1.5  ±  0.8°. The KC-Reg algorithm offers an independent check and quantitative QA of the surgical product using radiographic/fluoroscopic views acquired within standard OR workflow. Such intraoperative assessment could improve quality and safety, provide the opportunity to revise suboptimal constructs in the OR, and reduce the frequency of revision surgery.

Spinal screw placement is a challenging task due to small bone corridors and high risk of neurological or vascular complications, benefiting from precision guidance/navigation and quality assurance (QA). Implicit to both guidance and QA is the definition of a surgical plan-i.e. the desired trajectories and device selection for target vertebrae-conventionally requiring time-consuming manual annotations by a skilled surgeon. We propose automation of such planning by deriving the pedicle trajectory and device selection from a patient's preoperative CT or MRI. An atlas of vertebrae surfaces was created to provide the underlying basis for automatic planning-in this work, comprising 40 exemplary vertebrae at three levels of the spine (T7, T8, and L3). The atlas was enriched with ideal trajectory annotations for 60 pedicles in total. To define trajectories for a given patient, sparse deformation fields from the atlas surfaces to the input (CT or MR image) are applied on the annotated trajectories. Mean value coordinates are used to interpolate dense deformation fields. The pose of a straight trajectory is optimized by image-based registration to an accumulated volume of the deformed annotations. For evaluation, input deformation fields were created using coherent point drift (CPD) to perform a leave-one-out analysis over the atlas surfaces. CPD registration demonstrated surface error of 0.89  ±  0.10 mm (median  ±  interquartile range) for T7/T8 and 1.29  ±  0.15 mm for L3. At the pedicle center, registered trajectories deviated from the expert reference by 0.56  ±  0.63 mm (T7/T8) and 1.12  ±  0.67 mm (L3). The predicted maximum screw diameter differed by 0.45  ±  0.62 mm (T7/T8), and 1.26  ±  1.19 mm (L3). The automated planning method avoided screw collisions in all cases and demonstrated close agreement overall with expert reference plans, offering a potentially valuable tool in support of surgical guidance and QA.

Background: Chordomas are rare, locally aggressive bony tumors associated with poor outcomes. Recently, the single nucleotide polymorphism (SNP) rs2305089 in the T (brachyury) gene was strongly associated with sporadic chordoma development, but its clinical utility is undetermined., Methods: In 333 patients with spinal chordomas, we identified prognostic factors for local recurrence-free survival (LRFS) and overall survival and assessed the prognostic significance of the rs2305089 SNP., Results: The median LRFS was 5.2 years from the time of surgery (95% CI: 3.8-6.0); greater tumor volume (≥100cm3) (hazard ratio [HR] = 1.99, 95% CI: 1.26-3.15, P = .003) and Enneking inappropriate resections (HR = 2.35, 95% CI: 1.37-4.03, P = .002) were independent predictors of LRFS. The median overall survival was 7.0 years (95% CI: 5.8-8.4), and was associated with older age at surgery (HR = 1.11 per 5-year increase, 95% CI: 1.02-1.21, P = .012) and previous surgical resection (HR = 1.73, 95% CI: 1.03-2.89, P = .038). One hundred two of 109 patients (93.6%) with available pathologic specimens harbored the A variant at rs2305089; these patients had significantly improved survival compared with those lacking the variant (P = .001), but there was no association between SNP status and LRFS (P = .876)., Conclusions: The ability to achieve a wide en bloc resection at the time of the primary surgery is a critical preoperative consideration, as subtotal resections likely complicate later management. This is the first time the rs2305089 SNP has been implicated in the prognosis of individuals with chordoma, suggesting that screening all patients may be instructive for risk stratification., (© The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Pelvic Kirschner wire (K-wire) insertion is a challenging surgical task requiring interpretation of complex 3D anatomical shape from 2D projections (fluoroscopy) and delivery of device trajectories within fairly narrow bone corridors in proximity to adjacent nerves and vessels. Over long trajectories (~10-25 cm), K-wires tend to curve (deform), making conventional rigid navigation inaccurate at the tip location. A system is presented that provides accurate 3D localization and guidance of rigid or deformable surgical devices ("components" - e.g., K-wires) based on 3D-2D registration. The patient is registered to a preoperative CT image by virtually projecting digitally reconstructed radiographs (DRRs) and matching to two or more intraoperative x-ray projections. The K-wire is localized using an analogous procedure matching DRRs of a deformably parametrized model for the device component (deformable known-component registration, or dKC-Reg). A cadaver study was performed in which a K-wire trajectory was delivered in the pelvis. The system demonstrated target registration error (TRE) of 2.1 ± 0.3 mm in location of the K-wire tip (median ± interquartile range, IQR) and 0.8 ± 1.4° in orientation at the tip (median ± IQR), providing functionality analogous to surgical tracking/navigation using imaging systems already in the surgical arsenal without reliance on a surgical tracker. The method offers quantitative 3D guidance using images (e.g., inlet/outlet views) already acquired in the standard of care, potentially extending the advantages of navigation to broader utilization in trauma surgery to improve surgical precision and safety.

Study Design: Retrospective comparative study., Objective: To compare clinical and radiographic outcomes between the S2-alar-iliac (S2AI) and the iliac screw (IS) techniques in the adult population and clarify the clinical strength of S2AI screws., Summary of Background Data: S2AI screws have been described as an alternative method for lumbosacropelvic fixation in place of ISs. The S2AI technique has several advantages with lower prominence, increased ability to directly connect to proximal instrumentation, less extensive dissection of tissue, and enhanced biomechanical strength over the IS technique. However, the clinical significance of these advantages remains unclear., Methods: A single-center retrospective review of patients who underwent lumbosacropelvic fixation yielded 25 IS group patients and 65 S2AI group patients. Baseline demographic information, postoperative complications, pain and functional outcomes, and screw-related outcomes were collected., Results: The S2AI group had lower rates of reoperation (8.8% vs. 48.0%, P < 0.001), surgical site infection (SSI) (1.5% vs. 44.0%, P < 0.001), wound dehiscence (1.5% vs. 36.0%, P < 0.001), and symptomatic screw prominence (0.0% vs. 12.0%, P = 0.02) than the IS group, whereas rates of L5-S1 pseudarthrosis, proximal junctional failure, and sacroiliac joint pain were similar in both groups. Statistically significant pain relief and functional recovery were achieved in both groups without any significant intergroup differences. On multivariate analyses, age [odds ratio (OR) = 0.91, P = 0.004] and S2AI instrumentation (OR = 0.08, P < 0.001) were protective of reoperation, whereas diabetes mellitus (OR = 10.9, P = 0.03) and preoperative diagnosis of tumor (OR = 12.3, P = 0.04) were associated with SSI, and S2AI instrumentation (OR = 0.09, P < 0.001) was protective of SSI., Conclusion: The use of the S2AI technique over the IS technique was an independent predictor of preventing reoperation and SSI, while achieving similar clinical and functional outcomes., Level of Evidence: 4.

Decision support to assist in target vertebra localization could provide a useful aid to safe and effective spine surgery. Previous solutions have shown 3D-2D registration of preoperative CT to intraoperative radiographs to reliably annotate vertebral labels for assistance during level localization. We present an algorithm (referred to as MR-LevelCheck) to perform 3D-2D registration based on a preoperative MRI to accommodate the increasingly common clinical scenario in which MRI is used instead of CT for preoperative planning. Straightforward adaptation of gradient/intensity-based methods appropriate to CT-to-radiograph registration is confounded by large mismatch and noncorrespondence in image intensity between MRI and radiographs. The proposed method overcomes such challenges with a simple vertebrae segmentation step using vertebra centroids as seed points (automatically defined within existing workflow). Forwards projections are computed using segmented MRI and registered to radiographs via gradient orientation (GO) similarity and the CMA-ES (covariance-matrix-adaptation evolutionary-strategy) optimizer. The method was tested in an IRB-approved study involving 10 patients undergoing cervical, thoracic, or lumbar spine surgery following preoperative MRI. The method successfully registered each preoperative MRI to intraoperative radiographs and maintained desirable properties of robustness against image content mismatch and large capture range. Robust registration performance was achieved with projection distance error (PDE) (median  ±  IQR)  =  4.3  ±  2.6 mm (median  ±  IQR) and 0% failure rate. Segmentation accuracy for the continuous max-flow method yielded dice coefficient  =  88.1  ±  5.2, accuracy  =  90.6  ±  5.7, RMSE  =  1.8  ±  0.6 mm, and contour affinity ratio (CAR)  =  0.82  ±  0.08. Registration performance was found to be robust for segmentation methods exhibiting RMSE  <3 mm and CAR  >0.50. The MR-LevelCheck method provides a potentially valuable extension to a previously developed decision support tool for spine surgery target localization by extending its utility to preoperative MRI while maintaining characteristics of accuracy and robustness.

Objective: The primary objective of this study is to examine the effects smoking status on rhBMP-2 supplementation in spinal fusion constructs., Methods: Patient records were reviewed retrospectively for a consecutive set of patients who underwent first-time posterolateral, instrumented fusion of the lumbar spine for degenerative spinal disease. All operations included arthrodesis supplementation with rhBMP-2. All patients were followed for at least 2 years. The primary endpoint of this study was reoperation for pseudarthrosis, instrumentation failure, or adjacent segment disease. After a rigorous sensitivity analysis, the measure of association was calculated with a multivariable logistic regression controlling for smoking, age, and number of spinal levels fused., Results: Of the 110 patients in the study population, 82 (74.6%) were nonsmokers and 28 (25.5%) were smokers. Among perioperative predictors, smokers were younger in age (53.9 ± 9.6 vs. 61.1 ± 13.1 years; P = 0.008) and had shorter length of inpatient hospital stay (4.1 ± 1.8 vs. 5.3 ± 3.0; P = 0.039). After a mean follow-up of 59 months, the 32% incidence of reoperation for pseudarthrosis, instrumentation failure, or adjacent segment among smokers was statistically significantly higher than the 13.4% incidence in nonsmokers (P = 0.027). Following multivariable logistic regression, the odds of reoperation among smokers was 4.75-fold higher than for nonsmokers (P = 0.009; 95% confidence interval, 1.48-15.24)., Conclusions: While rhBMP-2 supplements arthrodesis of instrumented lumbar fusion constructs, smoking status ascertains the strongest predictor of reoperation for pseudarthrosis, instrumentation failure, and adjacent segment., (Copyright © 2016 Elsevier Inc. All rights reserved.)