Predictors of survival and time to progression following operative management of intramedullary spinal cord astrocytomas.

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.

Detection of tumor-derived DNA in cerebrospinal fluid of patients with primary tumors of the brain and spinal cord.

Cell-free DNA shed by cancer cells has been shown to be a rich source of putative tumor-specific biomarkers. Because cell-free DNA from brain and spinal cord tumors cannot usually be detected in the blood, we studied whether the cerebrospinal fluid (CSF) that bathes the CNS is enriched for tumor DNA, here termed CSF-tDNA. We analyzed 35 primary CNS malignancies and found at least one mutation in each tumor using targeted or genome-wide sequencing. Using these patient-specific mutations as biomarkers, we identified detectable levels of CSF-tDNA in 74% [95% confidence interval (95% CI) = 57-88%] of cases. All medulloblastomas, ependymomas, and high-grade gliomas that abutted a CSF space were detectable (100% of 21 cases; 95% CI = 88-100%), whereas no CSF-tDNA was detected in patients whose tumors were not directly adjacent to a CSF reservoir (P < 0.0001, Fisher's exact test). These results suggest that CSF-tDNA could be useful for the management of patients with primary tumors of the brain or spinal cord.

Robot-assisted resection of pre-sacral schwannoma.

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 .

Bone graft options for spinal fusion following resection of spinal column tumors: systematic review and meta-analysis.

OBJECTIVE With the advent of new adjunctive therapy, the overall survival of patients harboring spinal column tumors has improved. However, there is limited knowledge regarding the optimal bone graft options following resection of spinal column tumors, due to their relative rarity and because fusion outcomes in this cohort are affected by various factors, such as radiation therapy (RT) and chemotherapy. Furthermore, bone graft options are often limited following tumor resection because the use of local bone grafts and bone morphogenetic proteins (BMPs) are usually avoided in light of microscopic infiltration of tumors into local bone and potential carcinogenicity of BMP. The objective of this study was to review and meta-analyze the relevant clinical literature to provide further clinical insight regarding bone graft options. METHODS A web-based MEDLINE search was conducted in accordance with preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines, which yielded 27 articles with 383 patients. Information on baseline characteristics, tumor histology, adjunctive treatments, reconstruction methods, bone graft options, fusion rates, and time to fusion were collected. Pooled fusion rates (PFRs) and I2 values were calculated in meta-analysis. Meta-regression analyses were also performed if each variable appeared to affect fusion outcomes. Furthermore, data on 272 individual patients were available, which were additionally reviewed and statistically analyzed. RESULTS Overall, fusion rates varied widely from 36.0% to 100.0% due to both inter- and intrastudy heterogeneity, with a PFR of 85.7% (I2 = 36.4). The studies in which cages were filled with morselized iliac crest autogenic bone graft (ICABG) and/or other bone graft options were used for anterior fusion showed a significantly higher PFR of 92.8, compared with the other studies (83.3%, p = 0.04). In per-patient analysis, anterior plus posterior fusion resulted in a higher fusion rate than anterior fusion only (98.8% vs 86.4%, p < 0.001). Although unmodifiable, RT (90.3% vs 98.6%, p = 0.03) and lumbosacral tumors (74.6% vs 97.9%, p < 0.001) were associated with lower fusion rates in univariate analysis. The mean time to fusion was 5.4 ± 1.4 months (range 3-9 months), whereas 16 of 272 patients died before the confirmation of solid fusion with a mean survival of 3.1 ± 2.1 months (range 0.5-6 months). The average time to fusion of patients who received RT and chemotherapy were significantly longer than those who did not receive these adjunctive treatments (RT: 6.1 months vs 4.3 months, p < 0.001; chemotherapy: 6.0 months vs 4.3 months, p = 0.02). CONCLUSIONS Due to inter- and intrastudy heterogeneity in patient, disease, fusion criteria, and treatment characteristics, the optimal surgical techniques and factors predictive of fusion remain unclear. Clearly, future prospective, randomized studies will be necessary to better understand the issues surrounding bone graft selection following resection of spinal column tumors.

Highly personalized detection of minimal Ewing sarcoma disease burden from plasma tumor DNA.

BACKGROUND: Even though virtually all patients with Ewing sarcoma achieve a radiographic complete response, up to 30% of patients who present with localized disease and up to 90% of those who present with metastases experience a metastatic disease recurrence, highlighting the inability to identify patients with residual disease at the end of therapy. Up to 95% of Ewing sarcomas carry a driving EWS-ETS translocation that has an intronic breakpoint that is specific to each tumor, and the authors developed a system to quantitatively detect the specific breakpoint DNA fragment in patient plasma. METHODS: The authors used a long-range multiplex polymerase chain reaction (PCR) technique to identify tumor-specific EWS-ETS breakpoints in Ewing sarcoma cell lines, patient-derived xenografts, and patient tumors, and this sequence was used to design tumor-specific primer sets to detect plasma tumor DNA (ptDNA) by droplet digital PCR in xenograft-bearing mice and patients. RESULTS: Tumor-specific breakpoint DNA fragments were detected in the plasma of xenograft-bearing mice, and the signal correlated with tumor burden during primary tumor growth, after surgical resection, and at the time of metastatic disease recurrence. Furthermore, the authors were able to detect the specific breakpoint in plasma DNA obtained from 3 patients with Ewing sarcoma and in 2 patients the authors were able to detect ptDNA when there was radiographically undetectable disease present. CONCLUSIONS: The use of droplet digital PCR to detect tumor-specific EWS-ETS fusion gene breakpoint ptDNA fragments can be developed into a highly personalized biomarker of disease recurrence that can be optimized in animal studies for ultimate use in patients. Cancer 2016;122:3015-3023. © 2016 American Cancer Society.

Total en bloc spondylectomy for locally aggressive and primary malignant tumors of the lumbar spine.

PURPOSE: To report outcomes after total en bloc spondylectomy (TES) for primary aggressive/malignant tumors of the lumbar spine. METHODS: We performed a retrospective review of 23 neurosurgical patients operated between 2004 and 2014. Outcomes included perioperative complication rates and reoperation rates for instrumentation failure. The relationship between patient/operative parameters and complication development/instrumentation failure was investigated. RESULTS: There were 15 men (65.2 %) and eight women (24.8 %), with a median of 47 years. The most common tumor was chordoma in 11 patients (47.8 %), followed by sarcoma in four (17.4 %), and giant cell tumor in three (13.0 %). All patients but one underwent a two-staged operation; median total estimated blood loss was 3200 mL and median total operative time was 18.5 h. Fifteen patients developed at least one perioperative complication (65.2 %), with the most common being wound infection and ileus (26.1 % each). There was one case of intraoperative iliac vein injury (4.4 %). Instrumentation failure occurred in 9 patients (39.1 %) at a median time of 23 months after index spondylectomy. Following logistic regression, there were no factors associated with complication development. On the other hand, postoperative radiation was significantly associated with instrumentation failure (OR 7.49; 95 % CI, 1.02-54.9). Local recurrence and 5-year survival was 8.7 and 84.4 %, respectively. Median follow-up time was 50 months. CONCLUSIONS: Although favorable oncological outcomes after en bloc resection of spinal tumors may be achieved in terms of recurrence and survival, TES in the lumbar spine remains a challenging procedure. Future investigation into complication avoidance and reconstruction techniques is encouraged.

Factors associated with improved survival following surgery for renal cell carcinoma spinal metastases.

OBJECTIVE Renal cell carcinoma (RCC) frequently metastasizes to the spine, causing pain or neurological dysfunction, and is often resistant to standard therapies. Spinal surgery is frequently required, but may result in high morbidity rates. The authors sought to identify prognostic factors and determine clinical outcomes in patients undergoing surgery for RCC spinal metastases. METHODS The authors searched the records of patients who had undergone spinal surgery for metastatic disease at a single institution during a 12-year period and retrieved data for 30 patients with metastatic RCC. The records were retrospectively reviewed for data on preoperative conditions, treatment, and survival. Statistical analyses (i.e., Kaplan-Meier survival analysis and log-rank test in univariate analysis) were performed with R version 2.15.2. RESULTS The 30 patients (23 men and 7 women with a mean age of 57.6 years [range 29-79 years]) had in total 40 spinal surgeries for metastatic RCC. The indications for surgery included pain (70%) and weakness (30%). Fourteen patients (47%) had a Spinal Instability Neoplastic Score (SINS) indicating indeterminate or impending instability, and 6 patients (20%) had a SINS denoting instability. The median length of postoperative survival estimated with Kaplan-Meier analysis was 11.4 months. Younger age (p = 0.001) and disease control at the primary site (p = 0.005), were both significantly associated with improved survival. In contrast, visceral (p = 0.002) and osseous (p = 0.009) metastases, nonambulatory status (p = 0.001), and major comorbidities (p = 0.015) were all significantly associated with decreased survival. Postoperative Frankel grades were the same or had improved in 78% of patients. Major complications occurred in 9 patients, and there were 3 deaths (10%) during the 30-day in-hospital period. Three en bloc resections were performed. CONCLUSIONS Resection and fixation may provide pain relief and neurological stabilization in patients with spinal metastases arising from RCC, but surgical morbidity rates remain high. Younger patients with solitary spinal metastases, good neurological function, and limited major comorbidities may have longer survival and may benefit from aggressive intervention.

Clinical, surgical, and molecular prognostic factors for survival after spinal sarcoma resection.

OBJECTIVE The goal of this study was to investigate the local recurrence rate and long-term survival after resection of spinal sarcomas. METHODS A retrospective review of patients who underwent resection of primary or metastatic spinal sarcomas between 1997 and 2015 was performed. Tumors were classified according to the Enneking classification, and resection was categorized as Enneking appropriate (EA) if the specimen margins matched the Enneking recommendation, and as Enneking inappropriate (EI) if they did not match the recommendation. The primary outcome measure for all tumors was overall survival; local recurrence was also an outcome measure for primary sarcomas. The association between clinical, surgical, and molecular (tumor biomarker) factors and outcomes was also investigated. RESULTS A total of 60 patients with spinal sarcoma were included in this study (28 men and 32 women; median age 38 years). There were 52 primary (86.7%) and 8 metastatic sarcomas (13.3%). Thirty-nine tumors (65.0%) were classified as high-grade, and resection was considered EA in 61.7% of all cases (n = 37). The local recurrence rate was 10 of 52 (19.2%) for primary sarcomas; 36.8% for EI resection and 9.1% for EA resection (p = 0.010). Twenty-eight patients (46.7%) died during the follow-up period, and median survival was 26 months. Overall median survival was longer for patients with EA resection (undefined) compared with EI resection (13 months, p < 0.001). After multivariate analysis, EA resection significantly decreased the hazard of local recurrence (HR 0.24, 95% CI 0.06-0.93; p = 0.039). Age 40 years or older (HR 4.23, 95% CI 1.73-10.31; p = 0.002), previous radiation (HR 3.44, 95% CI 1.37-8.63; p = 0.008), and high-grade sarcomas (HR 3.17, 95% CI 1.09-9.23; p = 0.034) were associated with a significantly increased hazard of death, whereas EA resection was associated with a significantly decreased hazard of death (HR 0.22, 95% CI 0.09-0.52; p = 0.001). CONCLUSIONS The findings in the present study suggest that EA resection may be the strongest independent prognostic factor for improved survival in patients with spinal sarcoma. Additionally, patients who underwent EA resection had lower local recurrence rates. Patients 40 years or older, those with a history of previous radiation, and those with high-grade tumors had an increased hazard of mortality in this study.

Five-level cervical corpectomy for neurofibromatosis-associated spinal deformity: case report.

PURPOSE: To describe a successful five-level cervical corpectomy and circumferential reconstruction in a patient with a plexiform neurofibroma causing a severe kyphotic deformity. METHODS: Case report. RESULTS: 43-year-old man with history of Neurofibromatosis presented with signs and symptoms of myelopathy with spastic lower extremities and gait difficulties. Imaging studies demonstrated a severe kyphotic deformity of the cervical spine with associated cord compression secondary to an anteriorly positioned plexiform neurofibroma. Two-stage surgical procedure was designed to treat this lesion. Stage I consisted of tracheostomy placement, transmandibular, circumglossal approach to the anterior cervical spine, C2-C6 corpectomies, and C1-C7 reconstruction with a custom titanium cage/plate. Stage II consisted of suboccipital craniectomy, C1-C2 laminectomies, and occipital-cervical thoracic instrumented fusion (O-T8). There were no operative complications, but the patient did develop a small pulmonary embolism post-operatively treated with anticoagulation. Patient required two-weeks of inpatient rehabilitation following surgery. Gastrostomy tube and tracheostomy were successfully discontinued with preserved swallowing and respiratory function. Patient-reported outcome measurements revealed significant and sustained improvement post-operatively. CONCLUSIONS: Five-level cervical corpectomy including C2 can be safely and successfully performed via a transmandibular, circumglossal approach. Circumferential reconstruction utilizing a custom anterior titanium cage and plate system manufactured from a pre-operative CT scan was utilized in this case. Long segment occipital-cervical-thoracic reconstruction is recommended in such a case. Using such a technique, improvement in myelopathy, correction of deformity, and improved quality of life can be achieved.

Tokuhashi score is predictive of survival in a cohort of patients undergoing surgery for renal cell carcinoma spinal metastases.

PURPOSE: Renal cell carcinoma (RCC) is an aggressive disease that metastasizes to the spine often requiring surgery. However, selecting the appropriate surgical intervention can be challenging. The Tokuhashi scoring system can be used to predict survival and inform the surgical strategy. We set out to determine the Tokuhashi score for patients with RCC spine metastases and compare expected and observed survival. METHODS: Records were reviewed for all patients who underwent surgery for spinal metastases at a single institution from January 2000 to December 2011 to determine the Tokuhashi score and survival. Kaplan-Meier estimates and log-rank test for univariate analysis were performed with R version 2.15.12 (R Foundation, 2012). RESULTS: Thirty patients underwent 40 spinal operations for metastatic RCC. Median survival was 11.4 months. Preoperative Tokuhashi scores were: 12-15, 15 patients; 9-11, seven patients; 0-8, eight patients. Median survival was 32.9, 11.7, and 5.4 months, respectively. Bone (p=0.01) and visceral metastases (p=0.005), and KPS (p=0.002) significantly affected survival. Tokuhashi score predicted survival (p=0.016); survival differed between the high and low score groups (p=0.006). CONCLUSIONS: RCC is an aggressive disease with short life expectancy when metastatic to the spine. However, patients with low systemic disease burden and solitary spinal metastases can have long survival and benefit from excisional surgery. Tokuhashi score can be useful in selecting surgical intervention in patients with RCC spinal metastases, and may be more relevant than in other cancers with spinal metastases.

Surgical treatment of sarcomas of the spine.

OPINION STATEMENT: Primary sarcomas of the spine are rare diseases and include osteosarcoma, chondrosarcoma, chordoma, and Ewing's sarcoma. Surgery for these lesions remains an important part of their treatment. Strong evidence exists for the en bloc resection of chondrosarcoma and chordoma since these lesions respond poorly to both chemotherapy and radiation. Weaker but important evidence suggests that osteosarcoma and Ewing's sarcoma may also benefit from wide excisions, but after the application of neoadjuvant therapy, which may significantly aid the surgical process as well as independently prolong the survival. The unacceptable morbidity associated with damage to the neural elements makes resection with wide margins difficult in the spine. Nevertheless, this can be achieved in many circumstances and can, on occasion, lead to long term disease-free survival and even cure. There are numerous techniques described for en bloc resections in the mobile spine and pelvis and these vary widely for the region of the spine involved and the preferences of the surgeon. There are constant principles that do apply to all cases. We think of these surgeries as consisting of 2 stages which can be done in 1 or multiple operations. In the first phase, a corridor free of tumor is removed from the bone and the neural elements to be protected are dissected free from surrounding tissues. In the second phase, the tumor and a margin of normal tissue is circumferentially dissected and delivered while sparing the neural structures. Patient selection, in terms of age, overall disease burden, personal preferences, and comorbidities need to be carefully taken into account to optimize the risk benefit ratio. Sarcomas of the spine are a challenging group of lesions to treat but they can also be the most rewarding. Our newly acquired insight into the pathogenesis of these lesions, as well as improved surgical techniques combined with better neoadjuvant and adjuvant therapies are leading to longer survival times as well as long term disease free survivors.

Surgical anatomy of the diaphragm in the anterolateral approach to the spine: a cadaveric study.

STUDY DESIGN: Laboratory cadaveric study. OBJECTIVE: To delineate the pertinent surgical anatomy of the diaphragm during access to the anterolateral thoracolumbar junction. SUMMARY OF BACKGROUND DATA: The general anatomy of the thoracic diaphragm is well described. The specific surgical anatomy as it pertains to the lateral and thoracoabdominal approaches to the thoracolumbar junction is not well described. METHODS: Dissections were performed on adult fresh cadaveric specimens. Special attention was paid to the diaphragmatic attachments to the lower rib cage and to the spinal thoracolumbar junction. RESULTS: The pertinent diaphragmatic attachments to the rib cage are at the 11th and 12th ribs. Whether the diaphragm is incised or mobilized ventrally, the pertinent spinal attachments are the lateral and medial arcuate ligaments. Identifying and sectioning these structures allows for direct access to the thoracolumbar junction, particularly the L1 vertebral body. CONCLUSIONS: An understanding of the diaphragmatic-costal and diaphragmatic-spinal attachments is key for the safe and effective implementation of diaphragm mobilization during the lateral and thoracoabdominal approaches to the spine.

Robotic Resection of a Sciatic Notch Lipoma Using the DaVinci Surgical System: 2-Dimensional Operative Video.

Sciatic notch lipomas are rare benign fatty tumors that can cause significant morbidity due to compression of the sciatic nerve. Surgical excision is the gold standard treatment, but traditional open techniques are associated with significant risks and prolonged recovery times. Robotic surgery provides opportunity to improve on traditional laparoscopic techniques by allowing better visualization of and access to regions of complex anatomy, including the pelvis. The potential benefits of robotic resection include reduced blood loss, minimized tissue trauma, and shorter hospital stays. Building on robotic techniques previously described by our group, we present a video of a robotic resection of a sciatic notch lipoma using the DaVinci Surgical System.1,2 The patient consented to the procedure. The procedure begins with the patient in lithotomy position, followed by the establishment of the robotic trocar sites in the peritoneum, including the endoscope, Da Vinci, and assistant ports. The advanced visualization and precise maneuverability allow for careful dissection and identification of vital structures, including the L5 and S1 nerve roots, with minimal tissue manipulation. Subtotal resection of the lipoma was achieved resulting in decompression of the sciatic nerve with preservation of the surrounding structures. This video highlights the technical aspects of the procedure, emphasizing the advantages of robotic assistance, such as enhanced dexterity, precision, and visualization. This new technique offers a promising alternative to open surgery for the management of sciatic notch lipomas, potentially improving patient outcomes and overall surgical experience.

Neuronavigation in minimally invasive spine surgery.

OBJECT: Parallel advancements in image guidance technology and minimal access techniques continue to push the frontiers of minimally invasive spine surgery (MISS). While traditional intraoperative imaging remains widely used, newer platforms, such as 3D-fluoroscopy, cone-beam CT, and intraoperative CT/MRI, have enabled safer, more accurate instrumentation placement with less radiation exposure to the surgeon. The goal of this work is to provide a review of the current uses of advanced image guidance in MISS. METHODS: The authors searched PubMed for relevant articles concerning MISS, with particular attention to the use of image-guidance platforms. Pertinent studies published in English were further compiled and characterized into relevant analyses of MISS of the cervical, thoracic, and lumbosacral regions. RESULTS: Fifty-two studies were included for review. These describe the use of the iso-C system for 3D navigation during C1-2 transarticular screw placement, the use of endoscopic techniques in the cervical spine, and the role of navigation guidance at the occipital-cervical junction. The authors discuss the evolving literature concerning neuronavigation during pedicle screw placement in the thoracic and lumbar spine in the setting of infection, trauma, and deformity surgery and review the use of image guidance in transsacral approaches. CONCLUSIONS: Refinements in image-guidance technologies and minimal access techniques have converged on spinal pathology, affording patients the ability to undergo safe, accurate operations without the associated morbidities of conventional approaches. While percutaneous transpedicular screw placement is among the most common procedures to benefit from navigation, other areas of spine surgery can benefit from advances in neuronavigation and further growth in the field of image-guided MISS is anticipated.

Functional Anatomy and Biomechanics of the Craniovertebral Junction.

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.

Advances, Challenges, and Future Directions in the Management of Craniovertebral Junction Pathologies.

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.

An Approach to Managing Disorders Affecting the Craniovertebral Junction.

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.

Safety and Accuracy of Freehand Pedicle Screw Placement and the Role of Intraoperative O-Arm: A Single-Institution Experience.

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.

Neurological applications of belzutifan in von Hippel-Lindau disease.

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 impact of insurance status on outcomes after surgery for spinal metastases.

BACKGROUND: Disparities based on insurance status in the American health care system are well established. However, to the authors' knowledge, this is the first study to evaluate variables that may explain differences based on payer type in the outcomes after surgery for spinal metastases. METHODS: Data from the Nationwide Inpatient Sample (2005-2008) were retrospectively extracted. Patients ages 18 to 64 years who underwent surgery for spinal metastases were included. Multivariate logistic regression was performed to calculate the adjusted odds of in-hospital death and the development of a complication for Medicaid recipients and for those without insurance compared with privately insured patients. All analyses were adjusted for differences in patient age, gender, primary tumor histology, socioeconomic status, hospital bed size, and hospital teaching status. RESULTS: A total of 2157 hospital admissions were evaluated. The adjusted odds of in-hospital death were significantly higher for Medicaid recipients (crude rate: 6.5%; odds ratio [OR], 1.79; 95% confidence interval [95% CI], 1.11-2.88 [P = .02]) and uninsured patients (crude rate: 7.7%; OR, 2.15; 95% CI, 1.04-4.46 [P = .04]) compared with privately insured patients (crude rate: 3.8%). Complication rates were also significantly higher for Medicaid recipients (OR, 1.34; 95% CI, 1.04-1.72 [P = .02]). However, after also adjusting for acuity of presentation, the odds of in-hospital death were not significantly different for Medicaid (OR, 1.38; 95% CI, 0.86-2.21 [P = .18]) or uninsured patients (OR, 1.86; 95% CI, 0.90-3.83 [P = .09]); in addition, complication rates did not appear to differ significantly. CONCLUSIONS: This nationwide study suggests that disparities based on insurance status for patients undergoing surgery for spinal metastases may be attributable to a higher acuity of presentation.