Prognostic value of DNA methylation subclassification, aneuploidy, and CDKN2A/B homozygous deletion in predicting clinical outcome of IDH mutant astrocytomas

INTRODUCTION

IDH mutant astrocytoma grading, until recently, has been entirely based on morphology. The 5th edition of the Central Nervous System WHO introduces CDKN2A/B homozygous deletion as a biomarker of grade 4. We sought to investigate the prognostic impact of DNA methylation-derived molecular biomarkers for IDH mutant astrocytoma.

METHODS

We analyzed 98 IDH mutant astrocytomas diagnosed at NYU Langone Health between 2014 and 2022. We reviewed DNA methylation subclass, CDKN2A/B homozygous deletion, and ploidy and correlated molecular biomarkers with histological grade, progression free (PFS), and overall (OS) survival. Findings were confirmed using two independent validation cohorts.

RESULTS

There was no significant difference in OS or PFS when stratified by histologic WHO grade alone, copy number complexity, or extent of resection. OS was significantly different when patients were stratified either by CDKN2A/B homozygous deletion or by DNA methylation subclass (p-value=0.0286 and 0.0016, respectively). None of the molecular biomarkers were associated with significantly better progression free survival (PFS), although DNA methylation classification showed a trend (p-value= 0.0534).

CONCLUSIONS

The current WHO recognized grading criteria for IDH mutant astrocytomas show limited prognostic value. Stratification based on DNA methylation shows superior prognostic value for OS.

Percutaneous Juxtapedicular Cement Salvage of Failed Spinal Instrumentation? Institutional Experience and Cadaveric Biomechanical Study

BACKGROUND AND OBJECTIVES

Instrumented spinal fusion constructs sometimes fail because of fatigue loading, frequently necessitating open revision surgery. Favorable outcomes after percutaneous juxtapedicular cement salvage (perc-cement salvage) of failing instrumentation have been described; however, this approach is not widely known among spine surgeons , and its biomechanical properties have not been evaluated. We report our institutional experience with perc-cement salvage and investigate the relative biomechanical strength of this technique as compared with 3 other common open revision techniques.

METHODS

A retrospective chart review of patients who underwent perc-cement salvage was conducted. Biomechanical characterization of revision techniques was performed in a cadaveric model of critical pedicle screw failure. Three revision cohorts involved removal and replacement of hardware: (1) screw upsizing, (2) vertebroplasty, and (3) fenestrated screw with cement augmentation. These were compared with a cohort with perc-cement salvage performed using a juxtapedicular trajectory with the failed primary screw remaining engaged in the vertebral body.

RESULTS

Ten patients underwent perc-cement salvage from 2018 to 2022 to address screw haloing and/or endplate fracture threatening construct integrity. Pain palliation was reported by 8/10 patients. Open revision surgery was required in 4/10 patients, an average of 8.9 months after the salvage procedure (range 6.2-14.7 months). Only one revision was due to progressive hardware dislodgement. The remainder avoided open revision surgery through an average of 1.9 years of follow-up. In the cadaveric study, there were no significant differences in pedicle screw pullout strength among any of the revision cohorts.

CONCLUSION

Perc-cement salvage of failing instrumentation is reasonably efficacious. The technique is biomechanically noninferior to other revision strategies that require open surgery for removal and replacement of hardware. Open revision surgery may be avoided by perc-cement salvage in select cases.

Development and implementation of an Enhanced Recovery After Cranial Surgery pathway following supratentorial tumor resection at a tertiary care center

OBJECTIVE

Controlling length of stay (LOS) reduces rates of nosocomial infections and falls, facilitates earlier return to daily activities, and decreases strain on the healthcare system. Complications following supratentorial tumor resection present early in the postoperative period, thereby enhancing the prospect of safe, early discharge. Here, the authors describe their initial experience with the development and implementation of an Enhanced Recovery After Cranial Surgery (ERACS) pathway following resection of supratentorial tumors in select patients.

METHODS

This was a nonrandomized, ambispective quality improvement study of patients undergoing elective craniotomy for supratentorial tumor resection at New York University Langone Health between November 17, 2020, and May 19, 2022. Eligible patients were prospectively enrolled in either the ERACS pathway or the standard pathway. These prospective cohorts were compared to a retrospective cohort of patients who met eligibility criteria for the pathway. Patients in the ERACS pathway cohort were targeted for discharge on postoperative day 2. The primary outcome metric was hospital LOS. Secondary outcome metrics included duration of intensive care unit (ICU) care and rates of 30-day emergency department visits, readmissions, and complications.

RESULTS

Over the study period, 188 of 317 patients (59.3%) who underwent supratentorial tumor resection met inclusion criteria for ERACS pathway enrollment. Sixty-three patients were enrolled in the ERACS pathway, and 125 patients completed the standard pathway. The historical cohort consisted of 332 patients who would have been eligible for ERACS enrollment. Patients in the ERACS pathway cohort had a median LOS of 1.93 days compared with 2.92 and 2.88 days for patients in the standard pathway and historical cohort, respectively (p < 0.001). There was a significant reduction in ICU utilization in ERACS pathway patients (16.0 ± 6.53 vs 29.5 ± 53.0 vs 21.8 ± 18.2 hours, p = 0.005). There were no differences in the rates of 30-day emergency department visits (12.7% vs 9.6% vs 10.9%, p = 0.809) and readmissions (4.8% vs 4.0% vs 7.8%, p = 0.279) between groups.

CONCLUSIONS

Patients in the ERACS pathway cohort experienced reduced LOS and ICU utilization, with similar rates of adverse outcomes compared to standard pathway patients. The authors' initial experience suggests that an accelerated recovery pathway can be safely implemented following supratentorial tumor resection in select patients.

Developing an Automated Registry (Autoregistry) of Spine Surgery Using Natural Language Processing and Health System Scale Databases

BACKGROUND AND OBJECTIVES

Clinical registries are critical for modern surgery and underpin outcomes research, device monitoring, and trial development. However, existing approaches to registry construction are labor-intensive, costly, and prone to manual error. Natural language processing techniques combined with electronic health record (EHR) data sets can theoretically automate the construction and maintenance of registries. Our aim was to automate the generation of a spine surgery registry at an academic medical center using regular expression (regex) classifiers developed by neurosurgeons to combine domain expertise with interpretable algorithms.

METHODS

We used a Hadoop data lake consisting of all the information generated by an academic medical center. Using this database and structured query language queries, we retrieved every operative note written in the department of neurosurgery since our transition to EHR. Notes were parsed using regex classifiers and compared with a random subset of 100 manually reviewed notes.

RESULTS

A total of 31 502 operative cases were downloaded and processed using regex classifiers. The codebase required 5 days of development, 3 weeks of validation, and less than 1 hour for the software to generate the autoregistry. Regex classifiers had an average accuracy of 98.86% at identifying both spinal procedures and the relevant vertebral levels, and it correctly identified the entire list of defined surgical procedures in 89% of patients. We were able to identify patients who required additional operations within 30 days to monitor outcomes and quality metrics.

CONCLUSION

This study demonstrates the feasibility of automatically generating a spine registry using the EHR and an interpretable, customizable natural language processing algorithm which may reduce pitfalls associated with manual registry development and facilitate rapid clinical research.

Health Care Disparities in Transsphenoidal Surgery for Pituitary Tumors: An Experience from Neighboring Urban Public and Private Hospitals

Objectives  Few studies have assessed the role of socioeconomic health care disparities in skull base pathologies. We compared the clinical history and outcomes of pituitary tumors at private and public hospitals to delineate whether health care disparities exist in pituitary tumor surgery. Methods  We reviewed the records of patients who underwent transsphenoidal pituitary tumor resection at NYU Langone Health and Bellevue Hospital. Seventy-two consecutive patients were identified from each hospital. The primary outcome was time-to-surgery from initial recommendation. Secondary outcomes included postoperative diabetes insipidus, cerebrospinal fluid (CSF) leak, and gross total resection. Results  Of 144 patients, 23 (32%) public hospital patients and 24 (33%) private hospital patients had functional adenomas ( p  = 0.29). Mean ages for public and private hospital patients were 46.5 and 51.1 years, respectively ( p  = 0.06). Private hospital patients more often identified as white ( p  < 0.001), spoke English ( p  < 0.001), and had private insurance ( p  < 0.001). The average time-to-surgery for public and private hospital patients were 46.2 and 34.8 days, respectively ( p  = 0.39). No statistically significant differences were found in symptom duration, tumor size, reoperation, CSF leak, or postoperative length of stay; however, public hospital patients more frequently required emergency surgery ( p  = 0.03), developed transient diabetes insipidus ( p  = 0.02), and underwent subtotal resection ( p  = 0.04). Conclusion  Significant socioeconomic differences exist among patients undergoing pituitary surgery at our institution's hospitals. Public hospital patients more often required emergency surgery, developed diabetes insipidus, and underwent subtotal tumor resection. Identifying these differences is an imperative initial step in improving the care of our patients.

Digital Biomarkers and the Evolution of Spine Care Outcomes Measures: Smartphones and Wearables

Over the past generation, outcome measures in spine care have evolved from a reliance on clinician-reported assessment toward recognizing the importance of the patient's perspective and the wide incorporation of patient-reported outcomes (PROs). While patient-reported outcomes are now considered an integral component of outcomes assessments, they cannot wholly capture the state of a patient's functionality. There is a clear need for quantitative and objective patient-centered outcome measures. The pervasiveness of smartphones and wearable devices in modern society, which passively collect data related to health, has ushered in a new era of spine care outcome measurement. The patterns emerging from these data, so-called "digital biomarkers," can accurately describe characteristics of a patient's health, disease, or recovery state. Broadly, the spine care community has thus far concentrated on digital biomarkers related to mobility, although the researcher's toolkit is anticipated to expand in concert with advancements in technology. In this review of the nascent literature, we describe the evolution of spine care outcome measurements, outline how digital biomarkers can supplement current clinician-driven and patient-driven measures, appraise the present and future of the field in the modern era, as well as discuss present limitations and areas for further study, with a focus on smartphones (see Supplemental Digital Content , http://links.lww.com/NEU/D809 , for a similar appraisal of wearable devices).

Discontinuation of Postoperative Prophylactic Antibiotics for Endoscopic Endonasal Skull Base Surgery

Background  Postoperative prophylactic antibiotic usage for endoscopic skull base surgery varies based on the institution as evidence-based guidelines are lacking. The purpose of this study is to determine whether discontinuing postoperative prophylactic antibiotics in endoscopic endonasal cases led to a difference in central nervous system (CNS) infections, multi-drug resistant organism (MDRO) infections, or other postoperative infections. Methods  This quality improvement study compared outcomes between a retrospective cohort (from September 2013 to March 2019) and a prospective cohort (April 2019 to June 2019) after adopting a protocol to discontinue prophylactic postoperative antibiotics in patients who underwent endoscopic endonasal approaches (EEAs). Our primary end points of the study included the presence of postoperative CNS infection, Clostridium difficile ( C. diff ), and MDRO infections. Results  A total of 388 patients were analyzed, 313 in the pre-protocol group and 75 in the post-protocol group. There were similar rates of intraoperative cerebrospinal fluid leak (56.9 vs. 61.3%, p  = 0.946). There was a statistically significant decrease in the proportion of patients receiving IV antibiotics during their postoperative course ( p  = 0.001) and those discharged on antibiotics ( p  = 0.001). There was no significant increase in the rate of CNS infections in the post-protocol group despite the discontinuation of postoperative antibiotics (3.5 vs. 2.7%, p  = 0.714). There was no statistically significant difference in postoperative C. diff (0 vs. 0%, p  = 0.488) or development of MDRO infections (0.3 vs 0%, p  = 0.624). Conclusion  Discontinuation of postoperative antibiotics after EEA at our institution did not change the frequency of CNS infections. It appears that discontinuation of antibiotics after EEA is safe.

Up-front single-session radiosurgery for large brain metastases-volumetric responses and outcomes

BACKGROUND

Patients presenting with large brain metastases (LBM) pose a management challenge to the multidisciplinary neuro-oncologic team. Treatment options include surgery, whole-brain or large-field radiation therapy (WBRT), stereotactic radiosurgery (SRS), or a combination of these.

OBJECTIVE

To determine if corticosteroid therapy followed by SRS allows for efficient minimally invasive care in patients with LBMs not compromised by mass effect.

METHODS

We analyzed the change in tumor volume to determine the efficacy of single-session SRS in the treatment of LBM in comparison to other treatment modalities. Twenty-nine patients with systemic cancer and brain metastasis (≥ 2.7 cm in greatest diameter) who underwent single-session SRS were included.

RESULTS

Among 29 patients, 69% of patients had either lung, melanoma, or breast cancer. The median initial tumor size (maximal diameter) was 32 mm (range 28-43), and the median initial tumor volume was 9.56 cm³ (range 1.56-25.31). The median margin dose was 16 Gy (range 12-18). The average percent decrease in tumor volume compared to pre-SRS volume was 55% on imaging at 1-2 months, 58% at 3-5 months, 64% at 6-8 months, and 57% at > 8 months. There were no adverse events immediately following SRS. Median corticosteroid use after SRS was 21 days. Median survival after radiosurgery was 15 months.

CONCLUSION

Initial high-dose corticosteroid therapy followed by prompt single-stage SRS is a safe and efficacious method to manage patients with LBMs (defined as ≥ 2.7 cm).

Clinical utility of whole-genome DNA methylation profiling as a primary molecular diagnostic assay for central nervous system tumors-A prospective study and guidelines for clinical testing

Background

Central nervous system (CNS) cancer is the 10th leading cause of cancer-associated deaths for adults, but the leading cause in pediatric patients and young adults. The variety and complexity of histologic subtypes can lead to diagnostic errors. DNA methylation is an epigenetic modification that provides a tumor type-specific signature that can be used for diagnosis.

Methods

We performed a prospective study using DNA methylation analysis as a primary diagnostic method for 1921 brain tumors. All tumors received a pathology diagnosis and profiling by whole genome DNA methylation, followed by next-generation DNA and RNA sequencing. Results were stratified by concordance between DNA methylation and histopathology, establishing diagnostic utility.

Results

Of the 1602 cases with a World Health Organization histologic diagnosis, DNA methylation identified a diagnostic mismatch in 225 cases (14%), 78 cases (5%) did not classify with any class, and in an additional 110 (7%) cases DNA methylation confirmed the diagnosis and provided prognostic information. Of 319 cases carrying 195 different descriptive histologic diagnoses, DNA methylation provided a definitive diagnosis in 273 (86%) cases, separated them into 55 methylation classes, and changed the grading in 58 (18%) cases.

Conclusions

DNA methylation analysis is a robust method to diagnose primary CNS tumors, improving diagnostic accuracy, decreasing diagnostic errors and inconclusive diagnoses, and providing prognostic subclassification. This study provides a framework for inclusion of DNA methylation profiling as a primary molecular diagnostic test into professional guidelines for CNS tumors. The benefits include increased diagnostic accuracy, improved patient management, and refinements in clinical trial design.

The Cost Effectiveness of Implementation of a Postoperative Endocrinopathy Management Protocol after Resection of Pituitary Adenomas

Purpose  After developing a protocol for evaluating, diagnosing, and treating postoperative endocrinopathy both during the hospitalization and during the immediate discharge period following resection of pituitary adenomas, we sought to assess the impact of this protocol on quality outcomes. Methods  An IRB-exempt, quality improvement initiated, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective comparison of a pre-and-post-protocol cohort of all patients undergoing endoscopic endonasal resection of pituitary adenomas at NYU Langone Medical Center from January 2013 to December 2018. Demographic characteristics of the patients and their tumors with their postoperative outcomes were recorded. Quality outcomes regarding number of laboratory studies sent, rate of diabetes insipidus, length of stay, and readmission rate were also recorded. Statistical analysis was performed between the pre- and post-protocol groups. Results  There was a significant reduction in laboratory studies sent per patient (55.66 vs. 18.82, p <0.001). This corresponded with an overall cost reduction in laboratory studies of $255.95 per patient. There was a decrease in the overall number of patients treated with DDAVP (21.4% in the pre-protocol group vs. 8.9% in the post-protocol group, p  = 0.04). All post-protocol patients requiring DDAVP at discharge were identified by 48 hours. There was no significant change in length of stay or need for hydrocortisone supplementation postoperatively between the two groups. Length of stay was driven mostly by need for reoperation during initial hospitalization. There was no significant change in the rate of 30-day readmission. Conclusion  Implementation of a postoperative management protocol results in a more efficient diagnosis and management of endocrinopathy after pituitary adenoma surgery which translates to decreased cost.

The Value of Intraoperative Magnetic Resonance Imaging in Endoscopic Endonasal Resection of Pituitary Adenoma

Background  Intraoperative magnetic resonance images (iMRIs) have been variably adopted by some centers to help increase the rate of gross total resection (GTR) of pituitary adenomas. In this comparative study, we report our institution's experience with using iMRIs for endoscopic endonasal approach (EEA) pituitary adenoma resection to better elucidate its role and potential value for pituitary surgery. Methods  All adult patients who underwent EEA for a pituitary adenoma from January 2013 to September 2021 were retrospectively reviewed. GTR was defined as no residual tumor or recurrence on postoperative imaging within 6 months. Univariate analysis followed by multivariate analysis was performed with GTR as the categorical endpoint. To measure the independent effect of iMRI on GTR, propensity score matching was then performed. Results  A total of 351 pituitary adenoma patients who underwent EEA were identified. The mean age was 51.2 (range: 18-90) years and 196 (55.8%) patients were female. iMRI was utilized in 87 (24.8%) cases. The overall rate of GTR was 69.2%. On multivariate analysis, low Knosp grade, low tumor volume, and the use of iMRI were predictive of GTR. There was no difference in the need for desmopressin or hydrocortisone at 90 days postoperatively. Conclusion  At our institution, we report a significant absolute increase in GTR rates of 16.4% for patients undergoing an iMRI. Among iMRI patients who did not have GTR, the majority of residuals were intentionally left behind after being deemed too risky to pursue. Overall, this study suggests the high value that iMRI adds to endoscopic pituitary adenoma surgery.

SURG-24. QUANTITATIVE ANALYSIS OF TUMOR CELL DENSITY AND PROTOPORPHYRIN IX FLOURESCENCE IN GLIOMA PATIENTS USING PAIRED STIMULATED RAMAN HISTOLOGY AND TWO-PHOTON EXCITATION FLUORESCENCE MICROSCOPY

Fluorescence guidance is widely utilized to improve the precision of cancer surgery. 5-aminolevulinic acid, the most widely used fluorophore in glioma surgery, is thought to cause selective accumulation of fluorescent protoporphyrin IX (PpIX) in tumor cells by exploiting pathologic alterations in heme biosynthetic pathways. PpIX-induced fluorescence is highly specific for densely tumor-infiltrated tissue but less effective for visualizing the tumor periphery. To improve clinical detection of PpIX, we developed a microscope to perform paired stimulated Raman histology and two-photon excitation fluorescence microscopy (TPEF) and validated it in 175 fresh, unprocessed core tumor specimens from 75 high-grade glioma patients and three central nervous system lymphoma patients across three institutions. Surprisingly, intracellular PpIX accumulation was observed primarily in cells with histiocytic, rather than neoplastic morphology, and the number of cells concentrating PpIX within the cytoplasm was associated with the abundance of CD163 positive cells (p&lt; 0.02). There was no correlation between the degree of tumor cellularity and the concentration of PpIX across all imaged specimens (R=-0.21). Our findings encourage reconsideration of the existing theory of 5-ALA-induced tumor cell fluorescence in gliomas and demonstrate how 5-ALA and TPEF imaging can provide a window into the immune microenvironment of human gliomas.

Preoperative differentiation of hypophysitis and pituitary adenomas using a novel clinicoradiologic scoring system

PURPOSE

Hypophysitis can clinically and radiologically mimic other nonfunctioning masses of the sella turcica, complicating preoperative diagnosis. While sellar masses may be treated surgically, hypophysitis is often treated medically, so differentiating between them facilitates optimal management. The objective of our study was to develop a scoring system for the preoperative diagnosis of hypophysitis.

METHODS

A thorough literature review identified published hypophysitis cases, which were compared to a retrospective group of non-functioning pituitary adenomas (NFA) from our institution. A preoperative hypophysitis scoring system was developed and internally validated.

RESULTS

Fifty-six pathologically confirmed hypophysitis cases were identified in the literature. After excluding individual cases with missing values, 18 hypophysitis cases were compared to an age- and sex-matched control group of 56 NFAs. Diabetes insipidus (DI) (p < 0.001), infundibular thickening (p < 0.001), absence of cavernous sinus invasion (CSI) (p < 0.001), relation to pregnancy (p = 0.002), and absence of visual symptoms (p = 0.007) were significantly associated with hypophysitis. Stepwise logistic regression identified DI and infundibular thickening as positive predictors of hypophysitis. CSI and visual symptoms were negative predictors. A 6-point hypophysitis-risk scoring system was derived: + 2 for DI, + 2 for absence of CSI, + 1 for infundibular thickening, + 1 for absence of visual symptoms. Scores ≥ 3 supported a diagnosis of hypophysitis (AUC 0.96, sensitivity 100%, specificity 75%). The scoring system identified 100% of hypophysitis cases at our institution with an estimated 24.7% false-positive rate.

CONCLUSIONS

The proposed scoring system may aid preoperative diagnosis of hypophysitis, preventing unnecessary surgery in these patients.

Skull Base Aerosol Generating Cases Amidst the COVID-19 Pandemic: An Experience from the Epicenter

Soon after the World Health Organization declared the severe acute respiratory syndrome coronavirus 2 a global health emergency on January 30, 2020, New York City was plagued by the virus and its health system and economy pushed to their limits. The majority of the limited neurosurgical data in relation to COVID-19 is anecdotal and the higher theoretical risk of transmission of the virus among skull base aerosol generating (SBAG) cases has not been investigated or discussed in a neurosurgical population. We discuss a series of 13 patients who underwent 15 SBAG surgical procedures during the peak of COVID-19 in our hospital system and the protocols use perioperatively for their procedures. Our data support that with proper preoperative testing, a well-delineated surgical algorithm, and appropriate personal protective equipment, emergent/urgent cases can be done safely in hospitals that are currently experiencing high volumes of COVID-19 cases as we did in March to May of 2020.

Volumetric growth rates of untreated cavernous sinus meningiomas

OBJECTIVE

Meningiomas that arise primarily within the cavernous sinus are often believed to be more indolent in their growth pattern. Despite this perceived growth pattern, disabling symptoms can arise even with small tumors. While research has been done on cavernous sinus meningiomas (CSMs) and their treatment, very little is known about their natural growth rates. With a better understanding of the growth rate of CSM, patient treatment and guidance can be can optimized and individualized. The goal of this study was to determine volumetric growth rates of untreated CSMs.

METHODS

Thirty-seven patients with 166 MR images obtained between May 2004 and September 2019 were reviewed, with a range of 2-13 MR images per patient (average of 4.5 MR images per patient). These scans were obtained over an average follow-up period of 45.9 months (median 33.8, range 2.8-136.9 months). All imaging prior to any intervention was included in this analysis. Volumetric measurements were performed and assessed over time.

RESULTS

The estimated volumetric growth rate was 23.3% per year (95% CI 10.2%-38.0%, p < 0.001), which is equivalent to an estimated volume doubling time (VDT) of 3.3 years (95% CI 2.1-7.1 years). There was no significant relationship between growth rate and patient age (p = 0.09) or between growth rate and patient sex (p = 0.78). The median absolute growth rate was 41% with a range of -1% to 1793%. With a definition of "growth" as an increase of greater than 20% during the observed period, 65% of tumors demonstrated growth within their observation interval. Growth rates for each tumor were calculated and tumors were segmented based on growth rate. Of 37 patients, 22% (8) demonstrated no growth (< 5% annual growth, equivalent to a VDT > 13.9 years), 32% (12) were designated as slow growth (annual growth rate 5%-20%, VDT 3.5-13.9 years), 38% (14) were found to have medium growth (annual growth rate 20%-100%, VDT 0.7-3.5 years), and 8% were considered fast growing (annual growth rate > 100%, VDT < 0.7 years).

CONCLUSIONS

This study evaluated CSM volumetric growth rates. A deeper understanding of the natural history of untreated CSMs allows for better counseling and management of patients.

Stereotactic body radiation therapy for an unresectable FGF23-secreting tumor of the cervical spine: A case report and literature review

We present the case of a 65-year-old male with tumor-induced osteomalacia (TIO) caused by an FGF23-secreting phosphaturic tumor of C2 treated definitively with stereotactic body radiation therapy (SBRT) and kyphoplasty. The patient exhibited notable reduction in FGF23 6 weeks following radiotherapy. He also received a dose of the FGF23 monoclonal antibody, burosumab. We discuss the case with emphasis on radiation in the management of TIO. This case demonstrates SBRT as a well-tolerated local treatment option for the management of unresectable FGF23-producing tumors.

Tumor volume improves preoperative differentiation of prolactinomas and nonfunctioning pituitary adenomas

PURPOSE

Both prolactinomas and nonfunctioning adenomas (NFAs) can present with hyperprolactinemia. Distinguishing them is critical because prolactinomas are effectively managed with dopamine agonists, whereas compressive NFAs are treated surgically. Current guidelines rely only on serum prolactin (PRL) levels, which are neither sensitive nor specific enough. Recent studies suggest that accounting for tumor volume may improve diagnosis. The objective of this study is to investigate the diagnostic utility of PRL, tumor volume, and imaging features in differentiating prolactinoma and NFA.

METHODS

Adult patients with pathologically confirmed prolactinoma (n = 21) or NFA with hyperprolactinemia (n = 58) between 2013 and 2020 were retrospectively identified. Diagnostic performance of clinical and imaging variables was analyzed using receiver-operating characteristic curves to calculate area under the curve (AUC).

RESULTS

Tumor volume and PRL positively correlated for prolactinoma (r = 0.4839, p = 0.0263) but not for NFA (r = 0.0421, p = 0.7536). PRL distinguished prolactinomas from NFAs with an AUC of 0.8892 (p < 0.0001) and optimal cut-off value of 62.45 ng/ml, yielding a sensitivity of 85.71% and specificity of 94.83%. The ratio of PRL to tumor volume had an AUC of 0.9647 (p < 0.0001) and optimal cut-off value of 21.62 (ng/ml)/cm³ with sensitivity of 100% and specificity of 82.76%. Binary logistic regression found that PRL was a significant positive predictor of prolactinoma diagnosis, whereas tumor volume, presence of cavernous sinus invasion, and T2 hyperintensity were significant negative predictors. The regression model had an AUC of 0.9915 (p < 0.0001).

CONCLUSIONS

Consideration of tumor volume improves differentiation between prolactinomas and NFAs, which in turn leads to effective management.

Perioperative team communication through a mobile app for improving coordination and education in neurosurgery cases

OBJECTIVE

Miscommunication and poor coordination among surgical teams are known causes of preventable medical harms and operating room inefficiencies and inhibit surgical training. Technology may help overcome these challenges. This study used the personal experience of one of the authors as a former Air Force F-15 pilot to design a combat aviation pre- and postoperative communication workflow in the neurosurgery department and tested its effect on safety, efficiency, and education. The authors hypothesized that the adoption of this workflow through a tailored technological platform will increase compliance and improve the chances of sustainability.

METHODS

Data were prospectively collected from neurosurgery cases before (January-May 2020) and after (June-October 2020) implementation of this workflow. Briefing and debriefing were executed using a custom mobile platform and were defined as nonmandatory for all participants. All faculty and residents who operated at NYU Langone Medical Center (Tisch campus) during the intervention period were enrolled on the platform. Primary outcomes were morbidity and mortality per the department's criteria, and intraoperative last-minute requests as reported by operating room staff in a double-blinded fashion. Secondary outcomes were user responses on the subjective questionnaires.

RESULTS

Data were collected from 637 and 893 cases during the preintervention and intervention periods, respectively. The average briefing rates for residents and surgeons were 71% and 81%, respectively, and the average debriefing rates for residents and surgeons were 67% and 88%. There was no significant difference in preoperative risk score between the preintervention and intervention patient populations (p = 0.24). The rate of intraoperative last-minute requests significantly decreased from 16.6% (35/211) to 10.5% (35/334, p = 0.048). There was no significant change in morbidity and mortality between the preintervention and intervention periods. On subjective questionnaires there was a statistically significant improvement in safety, efficiency, and educational aspects of the cases during the intervention period.

CONCLUSIONS

Implementation of aviation-like structured team communication practices in the neurosurgery department through a technological platform improved education and communication between surgical teams and led to a reduction in last-minute surgical requests that could impact costs.

Transclival Approach for Resection of a Pontine Cavernous Malformation: 2-Dimensional Operative Video

Cerebral cavernous malformations are common vascular anomalies consisting of a cluster of capillaries without intervening brain tissue.1 A variety of approaches for resection have been undertaken,2 and a handful of case reports have described the endoscopic, endonasal, transclival approach.3 We present a case of a 51-yr-old woman with lupus and hepatitis B-associated cirrhosis who presented with diplopia, dysphagia, and ataxia. She had a left abducens nerve palsy and magnetic resonance imaging (MRI) showed a left pontine cavernous malformation. After a repeat hemorrhage, she consented to surgical resection. The lesion appeared to come to the medial pontine pial surface. Tractography indicated a rightward displacement of the left corticospinal tract. Therefore, an endoscopic, transnasal, transclival approach was chosen. A lumbar drain was placed preoperatively. The clivus and ventral petrous bone were drilled using the vidian canal to help identify the anterior genu of the petrous carotid artery. The clival dura was opened, revealing the abducens nerve exiting the ventral pons. The cavernoma was visible on the surface lateral to the nerve. It was removed using blunt dissection and the remaining cavity inspected. The skull base was reconstructed using an abdominal dermal-fat graft and Alloderm covered by a nasoseptal flap. Postoperatively she had transient swallowing difficulty. The lumbar drain was kept open for 5 d. Cerebrospinal fluid (CSF) leak was ruled out using an intrathecal fluorescein injection. She was discharged home, but presented 2 wk postoperatively with aseptic meningitis, which was treated supportively. Postoperative imaging did not show residual cavernoma.

Simultaneous Multislice for Accelerating Diffusion MRI in Clinical Neuroradiology Protocols

BACKGROUND AND PURPOSE

Diffusion MR imaging sequences essential for clinical neuroradiology imaging protocols may be accelerated with simultaneous multislice acquisitions. We tested whether simultaneous multislice-accelerated diffusion data were clinically equivalent to standard acquisitions.

MATERIALS AND METHODS

In this retrospective study, clinical diffusion sequences obtained before and after implementation of 2-slice simultaneous multislice acceleration and an altered diffusion gradient sampling scheme using the same 3T MRI scanner and 20-channel coil (n = 25 per group) were independently and blindly evaluated by 2 neuroradiologists for perceived quality, artifacts, and overall diagnostic utility. Diffusion tractography was performed in 13 patients both with and without 2-slice simultaneous multislice acceleration (b = 0, 1000, 2000 s/mm²; 60 directions). The corticospinal tract and arcuate fasciculus ipsilateral to the lesion were generated using the same ROIs and then blindly assessed by a neurosurgeon for anatomic fidelity, perceived quality, and impact on surgical management. Tract volumes were compared for spatial overlap.

RESULTS

Two-slice simultaneous multislice diffusion reduced acquisition times from 141 to 45 seconds for routine diffusion and from 7.5 to 5.9 minutes for diffusion tractography using 3T MR imaging. The simultaneous multislice-accelerated diffusion sequence was rated equivalent for diagnostic utility despite reductions to perceived image quality. Simultaneous multislice-accelerated diffusion tractography was rated clinically equivalent. Dice similarity coefficients between routine and simultaneous multislice-generated corticospinal tract and arcuate fasciculus tract volumes were 0.78 (SD, 0.03) and 0.71 (SD, 0.05), respectively.

CONCLUSIONS

Two-slice simultaneous multislice diffusion appeared clinically equivalent for standard acquisitions and diffusion tractography. Simultaneous multislice makes it feasible to acquire higher angular and q-space-resolution diffusion acquisitions required for translating advanced diffusion models into clinical practice.

Meningitis in the Setting of Frontoethmoidal and Temporal Meningoencephaloceles

This is a patient with multiple meningoencephaloceles which resulted in bacterial meningitis and subsequent status epilepticus. We identify impressive imaging findings demonstrating herniation of the meninges from nasal and bitemporal skull base defects possibly as a result of intracranial hypertension.

Venous Duplex Ultrasound Surveillance in the Neurosurgical Population: A Single-Center Quality Improvement Initiative

BACKGROUND

Venous thromboembolism (VTE) represents a significant source of morbidity and mortality in the inpatient population and is considered a leading preventable cause of death among inpatients. Neurosurgical inpatients are of particular interest because of the greater rates of immobility, steroid use, and potential consequences of postoperative hemorrhage. A consensus protocol for VTE screening in this population has not yet been developed, and institutional protocols vary widely.

METHODS

We performed a retrospective review of lower extremity venous duplex ultrasonography (VDUS) usage at our institution and applied this information to the development of a neurosurgery department protocol, with consideration of high-risk patient risk factors and indications for VDUS ordering. We then implemented this protocol, which consisted of preoperative screening of patients at high risk of VTE and limited postoperative surveillance, for a 6-month period and compared VDUS usage and VTE occurrence.

RESULTS

Preoperative VDUS screening before nonemergent neurosurgical procedures in high-risk patients with active cancer, an inability to ambulate, or a history of deep vein thrombosis (DVT) identified proximal DVTs that were then treated. Postoperative routine surveillance VDUS scans only diagnosed incidental isolated calf DVT for which no clinically relevant sequelae occurred. Overall, postoperative surveillance VDUS usage decreased significantly (66.9% vs. 13.5%; P = 0.001).

CONCLUSIONS

Our findings lend support to preoperative screening of high-risk patients and suggest that routine postoperative VDUS surveillance of asymptomatic patients is unnecessary.

Benefits of the Subdural Evacuating Port System (SEPS) Procedure Over Traditional Craniotomy for Subdural Hematoma Evacuation

Background

There remains no consensus on the optimal primary intervention for subdural hematoma (SDH). Although historically favored, craniotomy carries substantial morbidity and incurs significant costs. Contrastingly, the subdural evacuating port system (SEPS) is a minimally invasive bedside procedure. We assessed the benefits of SEPS over traditional craniotomy for SDH evacuation.

Methods

A single-center retrospective cohort study of SDH patients receiving craniotomy or SEPS between 2012 and 2017 was performed. Information regarding demographics, medical history, presentation, surgical outcomes, cost, and complications was collected. Pre- and postoperative hematoma volumes were calculated using 3D image segmentation using Vitrea software. Multivariate regression models were employed to assess the influence of intervention choice.

Results

Of 107 patients, 68 underwent craniotomy and 39 underwent SEPS. There were no differences in age, sex, blood thinner use, platelet count, INR, hematoma lateralization, age, volume, or midline shift at presentation between intervention groups. Although there was no difference in percent residual hematoma volume 24-hour postintervention (44.1% vs 45.1%, P = .894), SEPS was associated with lower hospitalization costs ($108 391 vs $166 318, *P = .002), shorter length of stay (4.0 vs 5.8 days, *P = .0002), and fewer postoperative seizures (2.6% vs 17.7%, *P = .048). Reoperation rate was higher after SEPS overall (33.3% vs 13.2%, *P = .048) but comparable to craniotomy in chronic SDH (12.50% vs 7.69%, P = 1.000).

Conclusion

In this retrospective cohort, SEPS was noninferior to craniotomy at reducing SDH hematoma volume. The SEPS procedure was also associated with decreased length of stay hospitalization costs, and postoperative seizures and demonstrated a comparable recurrence rate to craniotomy for chronic SDH in particular.

RADI-28. UP-FRONT SINGLE SESSION RADIOSURGERY FOR LARGE BRAIN METASTASES - VOLUMETRIC RESPONSES AND OUTCOMES

OBJECTIVE: Patients presenting with large brain metastases (LBM), described in the literature as ≥2.5 cm in maximum diameter or ≥10cm³in volume, pose a management challenge. For patients not compromised by mass effect, corticosteroid therapy followed by SRS allows for efficient, minimal access care that facilitates immediate institution of systemic therapy. METHODS: We performed a volumetric-based analysis in order to determine the efficacy of single-session SRS in the treatment of LBM in comparison to other treatment modalities. Thirty patients over the age of 18 with systemic cancer and brain metastases (≥2.7cm in greatest diameter or ≥10cm³in volume) who underwent single session SRS were included. Serial tumor volumes, clinical outcomes, and medication requirements were studied. RESULTS: Among 30 patients, 70% of patients had either lung, melanoma, or breast cancer. Median initial tumor size (maximum diameter) was 32mm (range 28–43) and median initial tumor volume was 9.32cm³ (range 1.09–25.31). Median marginal dose was 16Gy (range 12–18). Average percent decrease in tumor volume was 50% on imaging at 4–8 weeks, 60% at 4–6 months, 48% at 6–8 months, and 67% at >8 months compared to initial imaging. Only one patient required a subsequent craniotomy 4 years after SRS for an enlarging cyst which was granulation tissue consistent with radiation effects on pathology. There were no adverse events immediately following SRS. Median corticosteroid use after SRS was 21 days. There was no statistically significant difference in KPS score between treatment day and last follow up, suggesting relative safety and maintenance of function. CONCLUSION: Initial high dose corticosteroid therapy followed by prompt single session SRS is a safe and efficacious method of managing patients with large brain metastases (defined in our study as ≥2.7cm or ≥10cm³), if the clinical condition of the patient is acceptable at presentation.

FOLLICLE-STIMULATING HORMONE-PRODUCING PITUITARY ADENOMA: A CASE REPORT AND REVIEW OF THE LITERATURE

Objective

To describe an unusual presentation of a follicle-stimulating hormone-secreting pituitary adenoma leading to ovarian hyperstimulation syndrome. We also discuss the pathophysiology and subsequent management of these tumors.

Methods

This is a case report and review of the literature. A 37-year-old female with menorrhagia was found to have bilateral multilocular adnexal cysts with concern for ovarian hyperstimulation syndrome.

Results

Labs revealed elevated follicle-stimulating hormone, and an eminent estradiol level. Pituitary magnetic resonance imaging revealed a macroadenoma with cavernous sinus invasion. The patient went on to have a successful transsphenoidal resection with normalization of hormones and subsequent resumption of menstrual cycles.

Conclusion

With the help of this case report, we illustrate the pathogenesis of functioning gonadotroph adenomas as well as the management challenges associated with these tumors. Our case is unique in its presentation with severe hyperestrogenemia and cavernous sinus invasion pointing towards a clinically aggressive adenoma. It is important to increase awareness of these tumors to ensure timely and effective management of their complications.

Combined Use of Diffusion Tractography and Advanced Intraoperative Imaging for Resection of Cervical Intramedullary Spinal Cord Neoplasms: A Case Series and Technical Note

BACKGROUND

Intramedullary spinal cord neoplasms (ISCN) pose significant management challenges. Advances in magnetic resonance imaging (MRI) (such as diffusion tensor imaging, DTI) have been utilized to determine the infiltrative nature and resectability of ISCN. However, this has not been applied to intraoperative decision making.

OBJECTIVE

To present a case series of 2 patients with ISCN, the first to combine use of DTI, pre- and intraoperative 3-dimensional (3D) virtual reality imaging, and microscope integrated navigation with heads-up display.

METHODS

Two patients who underwent surgery for ISCN were included. DTI images were obtained and 3D images were created using Surgical Theater (Surgical Theater SRP, Version 7.4.0, Cleveland, Ohio). Fiducials were used to achieve accurate surface registration to C4. Navigation confirmed the levels of laminectomy necessary. The microscope was integrated with Brainlab (Brainlab AG Version 3.0.5, Feldkirchen, Germany) and the tumor projected in the heads-up display. Surgical Theater was integrated with Brainlab to allow for real time evaluation of the 3D tractography.

RESULTS

Case 1: All tracts were pushed away from the tumor, suggesting it was not infiltrative. Surgical Theater and Brainlab assisted in confirming midline despite the abnormal swelling of the cord so the myelotomy could be performed. The heads-up display outline demonstrated excellent correlation to the tumor. Gross total resection was achieved. Diagnosis of ependymoma was confirmed. Case 2: Some tracts were going through the tumor itself, suggesting an infiltrative process. Surgical Theater and Brainlab again allowed for confirmation of the midline raphe. Near total resection of the enhancing portion was achieved. Diagnosis of glioblastoma was confirmed.

CONCLUSION

This is a proof of concept application where multi-modal imaging technology was utilized for safest maximal ISCN resection.

Endovascular and Microsurgical Aneurysm Training in a Chicken Thigh and Leg Pulsatile Model

BACKGROUND

Neurovascular training models include animal models, synthetics, or computer simulation. In vivo models are expensive and require significant resources. Synthetic/computer models do not reflect the elasticity of fresh vessels. We describe an endovascular and microsurgical training model using a chicken thigh/leg.

METHODS

20 chicken thigh/leg models were obtained. Angiography was utilized to understand the anatomy. Proximal cannulation with a 5-French catheter was achieved and connected to a hemostatic valve with a pump to simulate pulsatile flow. Aneurysms were created at the thigh-leg junction. For clipping training, 3 types of aneurysms were created to reproduce anatomy seen in middle cerebral, anterior communicating and posterior communicating aneurysms.

RESULTS

The average cost per specimen from was $1.70 ± 0.30. The diameter of the proximal femoral artery (PFA) was 2.4 mm ± 0.2 mm. The length from the PFA to the aneurysm was 9.5 cm ± 0.7 cm. Distal catheterization was successful in all cases (n=6). Successful deployment of coils and a stent was achieved under fluoroscopic guidance. Gross over-sizing of coils and other mistakes led to aneurysm rupture. Each examiner performed an exploration of the pulsatile aneurysm, application and reapplication of a variety of clips and then final inspection of branching vessels to confirm patency.

CONCLUSIONS

The chicken thigh/leg model provides training opportunities in microsurgical suturing, endovascular techniques for aneurysm obliteration, and microsurgical reconstruction of aneurysms. It combines affordability, time efficiency and reproducibility. Further studies measuring improvement in technical aneurysm management and comparison to other training models are warranted.

Postoperative cerebral venous sinus thrombosis in the setting of surgery adjacent to the major dural venous sinuses

OBJECTIVECerebral venous sinus thrombosis (CVST) is a known complication of surgeries near the major dural venous sinuses. While the majority of CVSTs are asymptomatic, severe sinus thromboses can have devastating consequences. The objective of this study was to prospectively evaluate the true incidence and risk factors associated with postoperative CVST and comment on management strategies.METHODSA prospective study of 74 patients who underwent a retrosigmoid, translabyrinthine, or suboccipital approach for posterior fossa tumors, or a supratentorial craniotomy for parasagittal/falcine tumors, was performed. All patients underwent pre- and postoperative imaging to evaluate sinus patency. Demographic, clinical, and operative data were collected. Statistical analysis was performed to identify incidence and risk factors.RESULTSTwenty-four (32.4%) of 74 patients had postoperative MR venograms confirming CVST, and all were asymptomatic. No risk factors, including age (p = 0.352), BMI (p = 0.454), sex (p = 0.955), surgical approach (p = 0.909), length of surgery (p = 0.785), fluid balance (p = 0.943), mannitol use (p = 0.136), tumor type (p = 0.46, p = 0.321), or extent of resection (p = 0.253), were statistically correlated with thrombosis. All patients were treated conservatively, with only 1 patient receiving intravenous fluids. There were no instances of venous infarctions, hemorrhages, or neurological deficits. The rate of CSF leakage was significantly higher in the thrombosis group than in the nonthrombosis group (p = 0.01).CONCLUSIONSThis prospective study shows that the radiographic incidence of postoperative CVST is higher than that previously reported in retrospective studies. In the absence of symptoms, these thromboses can be treated conservatively. While no risk factors were identified, there may be an association between postoperative CVST and CSF leak.

Discontinuation of Postoperative Prophylactic Antibiotics After Noninstrumented Spinal Surgery: Results of a Quality Improvement Project

BACKGROUND

Numerous medical society guidelines recommend discontinuation of antibiotics at a maximum of 24 hours after noninstrumented spinal surgery, even when a drain is left in place. As a result of these recommendations, our institution's Neurosurgery Quality Improvement Committee decided to stop administering prolonged prophylactic systemic antibiotics (PPSAs) to patients with drains after noninstrumented spinal surgery.

METHODS

We retrospectively reviewed data for patients who had noninstrumented spinal surgery performed by a neurosurgeon at our institution between December 2012 and July 2014 (PPSA period) and December 2014 and July 2016 (non-PPSA period) and had a drain left in place postoperatively. In the PPSA period, patients received antibiotics until drain removal. In the non-PPSA period, patients received antibiotics for a maximum of 24 hours.

RESULTS

We identified 58 patients in the PPSA period and 55 in the non-PPSA period. Discontinuation of PPSAs resulted in a nonsignificant increase in the frequency of surgical site infections (SSIs; 0% in the PPSA period vs 4% in the non-PPSA period; P = .24).

CONCLUSION

After discontinuing PPSAs for patients with noninstrumented spinal procedures, as is recommended for quality improvement, we saw a nonsignificant increase in our rate of SSIs. Further monitoring of this population is warranted.

Results of a quality improvement initiative reassessing an institutional lumbar drain infection prevention protocol

OBJECTIVE The objective of this study was to determine the effects of a quality improvement initiative in which daily antibiotics and daily sampling of cerebrospinal fluid (CSF) were discontinued for patients with lumbar drains. METHODS The frequency of surgical site infections (SSIs), antibiotic-related complications (development of Clostridium difficile infection [CDI] and growth of resistant bacteria), and cost for patients with lumbar drains were compared during 3 periods: 1) prolonged prophylactic systemic antibiotics (PPSA) until the time of drain removal and daily CSF sampling (September 2013-2014), 2) PPSA and CSF sampling once after placement then as needed (January 2015-2016), and 3) antibiotics only during placement of the lumbar drain and CSF sampling once after placement then as needed (April 2016-2017). RESULTS Thirty-nine patients were identified in period 1, 53 patients in period 2, and 39 patients in period 3. There was no change in the frequency of SSI after discontinuation of routine CSF testing or PPSA (0% in period 1, 2% in period 2, and 0% in period 3). In periods 1 and 2, 3 patients developed infections due to resistant organisms and 2 patients had CDI. In period 3, 1 patient had an infection due to a resistant organism. The median cost of CSF tests per patient was $100.68 (interquartile range [IQR] $100.68-$134.24) for patients in period 1 and $33.56 (IQR $33.56-$33.56) in periods 2 and 3 (p < 0.001). The median cost of antibiotics per patient was $26.32 (IQR $26.32-$30.65) in periods 1 and 2 and $3.29 ($3.29-$3.29) in period 3 (p < 0.001). The cost associated with growth of resistant bacteria and CDI was $91,291 in periods 1 and 2 and $25,573 in period 3. CONCLUSIONS After discontinuing daily antibiotics and daily CSF sampling for patients with lumbar drains, the frequency of SSI was unchanged and the frequency of antibiotic-related complications decreased.

Mutant IDH1 and seizures in patients with glioma

OBJECTIVE

Because the d-2-hydroxyglutarate (D2HG) product of mutant isocitrate dehydrogenase 1 (IDH1^mut) is released by tumor cells into the microenvironment and is structurally similar to the excitatory neurotransmitter glutamate, we sought to determine whether IDH1^mut increases the risk of seizures in patients with glioma, and whether D2HG increases the electrical activity of neurons.

METHODS

Three WHO grade II-IV glioma cohorts from separate institutions (total N = 712) were retrospectively assessed for the presence of preoperative seizures and tumor location, WHO grade, 1p/19q codeletion, and IDH1^mut status. Rat cortical neurons were grown on microelectrode arrays, and their electrical activity was measured before and after treatment with exogenous D2HG, in the presence or absence of the selective NMDA antagonist, AP5.

RESULTS

Preoperative seizures were observed in 18%-34% of IDH1 wild-type (IDH1^wt) patients and in 59%-74% of IDH1^mut patients (p < 0.001). Multivariable analysis, including WHO grade, 1p/19q codeletion, and temporal lobe location, showed that IDH1^mut was an independent correlate with seizures (odds ratio 2.5, 95% confidence interval 1.6-3.9, p < 0.001). Exogenous D2HG increased the firing rate of cultured rat cortical neurons 4- to 6-fold, but was completely blocked by AP5.

CONCLUSIONS

The D2HG product of IDH1^mut may increase neuronal activity by mimicking the activity of glutamate on the NMDA receptor, and IDH1^mut gliomas are more likely to cause seizures in patients. This has rapid translational implications for the personalized management of tumor-associated epilepsy, as targeted IDH1^mut inhibitors may improve antiepileptic therapy in patients with IDH1^mut gliomas.

C-2 arteriovenous fistula presenting as a pathologic hangman's fracture: case report

The authors report on an 81-year-old woman with a pathologic hangman's fracture secondary to a complex arteriovenous fistula (AVF). The patient presented with severe, unremitting neck pain and was found to have fractures bilaterally through the pars interarticularis of C-2 with significant anterior subluxation of C-2 over C-3 along with widening of the left transverse foramen. Due to an abnormally appearing left vertebral artery (VA) on CT angiography, the patient underwent conventional angiography, which revealed a complex AVF stemming from the left VA at the level of C-2 with dilated posterior cervical veins and a large venous varix. Given the radiographic evidence of bone remodeling and the chronicity of the AVF, it is believed that the C-2 vertebra was weakened over time by the pulsatile and compressive force of the vascular malformation eventually leading to fracture with minimal stress. Coil embolization of the AVF was performed followed by surgical fixation of C-1 to C-4. This case highlights the importance of investigating an underlying disease process in patients who present with significant spinal fractures in the absence of trauma.

Mutant IDH1 and thrombosis in gliomas

Mutant isocitrate dehydrogenase 1 (IDH1) is common in gliomas, and produces D-2-hydroxyglutarate (D-2-HG). The full effects of IDH1 mutations on glioma biology and tumor microenvironment are unknown. We analyzed a discovery cohort of 169 World Health Organization (WHO) grade II-IV gliomas, followed by a validation cohort of 148 cases, for IDH1 mutations, intratumoral microthrombi, and venous thromboemboli (VTE). 430 gliomas from The Cancer Genome Atlas were analyzed for mRNAs associated with coagulation, and 95 gliomas in a tissue microarray were assessed for tissue factor (TF) protein. In vitro and in vivo assays evaluated platelet aggregation and clotting time in the presence of mutant IDH1 or D-2-HG. VTE occurred in 26-30 % of patients with wild-type IDH1 gliomas, but not in patients with mutant IDH1 gliomas (0 %). IDH1 mutation status was the most powerful predictive marker for VTE, independent of variables such as GBM diagnosis and prolonged hospital stay. Microthrombi were far less common within mutant IDH1 gliomas regardless of WHO grade (85-90 % in wild-type versus 2-6 % in mutant), and were an independent predictor of IDH1 wild-type status. Among all 35 coagulation-associated genes, F3 mRNA, encoding TF, showed the strongest inverse relationship with IDH1 mutations. Mutant IDH1 gliomas had F3 gene promoter hypermethylation, with lower TF protein expression. D-2-HG rapidly inhibited platelet aggregation and blood clotting via a novel calcium-dependent, methylation-independent mechanism. Mutant IDH1 glioma engraftment in mice significantly prolonged bleeding time. Our data suggest that mutant IDH1 has potent antithrombotic activity within gliomas and throughout the peripheral circulation. These findings have implications for the pathologic evaluation of gliomas, the effect of altered isocitrate metabolism on tumor microenvironment, and risk assessment of glioma patients for VTE.

Palliative CT-Guided Cordotomy for Medically Intractable Pain in Patients with Cancer

Palliative cervical cordotomy can be performed via percutaneous radiofrequency ablation of the lateral C1-2 spinothalamic tract. This rare procedure can be safe, effective, and advantageous in mitigating medically intractable unilateral extremity pain for selected patients with end-stage cancer. This report reviews the indications, techniques, risks, and potential benefits of cordotomy. We describe our recent experience treating 3 patients with CT-guided C1-2 cordotomy and provide the first characterization of spinal cord diffusion MR imaging changes associated with successful cordotomy.

GPR133 (ADGRD1), an adhesion G-protein-coupled receptor, is necessary for glioblastoma growth

Glioblastoma (GBM) is a deadly primary brain malignancy with extensive intratumoral hypoxia. Hypoxic regions of GBM contain stem-like cells and are associated with tumor growth and angiogenesis. The molecular mechanisms that regulate tumor growth in hypoxic conditions are incompletely understood. Here, we use primary human tumor biospecimens and cultures to identify GPR133 (ADGRD1), an orphan member of the adhesion family of G-protein-coupled receptors, as a critical regulator of the response to hypoxia and tumor growth in GBM. GPR133 is selectively expressed in CD133+ GBM stem cells (GSCs) and within the hypoxic areas of PPN in human biospecimens. GPR133 mRNA is transcriptionally upregulated by hypoxia in hypoxia-inducible factor 1α (Hif1α)-dependent manner. Genetic inhibition of GPR133 with short hairpin RNA reduces the prevalence of CD133+ GSCs, tumor cell proliferation and tumorsphere formation in vitro. Forskolin rescues the GPR133 knockdown phenotype, suggesting that GPR133 signaling is mediated by cAMP. Implantation of GBM cells with short hairpin RNA-mediated knockdown of GPR133 in the mouse brain markedly reduces tumor xenograft formation and increases host survival. Analysis of the TCGA data shows that GPR133 expression levels are inversely correlated with patient survival. These findings indicate that GPR133 is an important mediator of the hypoxic response in GBM and has significant protumorigenic functions. We propose that GPR133 represents a novel molecular target in GBM and possibly other malignancies where hypoxia is fundamental to pathogenesis.

Antibiotic prophylaxis for subdural and subgaleal drains

OBJECTIVE The authors sought to determine the effects of eliminating the use of prolonged prophylactic systemic antibiotics (PPSAs) in patients with subdural and subgaleal drains. METHODS Using a retrospective database, the authors collected data for patients over the age of 17 years who had undergone cranial surgery at their institution between December 2013 and July 2014 (PPSAs period) or between December 2014 and July 2015 (non-PPSAs period) and had subdural or subgaleal drains left in place postoperatively. RESULTS One hundred five patients in the PPSAs period and 80 in the non-PPSAs period were identified. The discontinuation of PPSAs did not result in an increase in the frequency of surgical site infection (SSI). The frequency of Clostridium difficile (CDI) and the growth of resistant bacteria were reduced in the non-PPSAs period in comparison with the PPSAs period. In the 8 months after the drain prophylaxis protocol was changed, $93,194.63 were saved in the costs of antibiotics and complications related to antibiotics. CONCLUSIONS After discontinuing PPSAs for patients with subdural or subgaleal drains at their institution, the authors did not observe an increase in the frequency of SSI. They did, however, note a decrease in the frequency of CDI and the growth of resistant organisms. It appears that not only can patients in this population do without PPSAs, but also that complications are avoided when antibiotic use is limited to 24 hours after surgery.