Link, Michael J.

ImportanceManagement of sporadic vestibular schwannoma with radiosurgery is becoming increasingly common globally; however, limited data currently characterize patient outcomes in the setting of microsurgical salvage for radiosurgical failure.ObjectiveTo describe the clinical outcomes of salvage microsurgery following failed primary stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) among patients with sporadic vestibular schwannoma.Design, Setting, and ParticipantsThis was a cohort study of adults (≥18 years old) with sporadic vestibular schwannoma who underwent salvage microsurgery following failed primary SRS/FSRT in 7 vestibular schwannoma treatment centers across the US and Norway. Data collection was performed between July 2022 and January 2023, with data analysis performed between January and July 2023.ExposureSalvage microsurgical tumor resection.Main Outcomes and MeasuresComposite outcome of undergoing less than gross total resection (GTR) or experiencing long-term facial paresis.ResultsAmong 126 patients, the median (IQR) age at time of salvage microsurgery was 62 (53-70) years, 69 (55%) were female, and 113 of 117 (97%) had tumors that extended into the cerebellopontine angle at time of salvage. Of 125 patients, 96 (76%) underwent primary gamma knife SRS, while 24 (19%) underwent linear accelerator-based SRS; the remaining patients underwent FSRT using other modalities. Postoperative cerebrospinal fluid leak was seen in 15 of 126 patients (12%), hydrocephalus in 8 (6%), symptomatic stroke in 7 (6%), and meningitis in 2 (2%). Each 1-mm increase in cerebellopontine angle tumor size was associated with a 13% increased likelihood of foregoing GTR (64 of 102 patients [63%]) or long-term postoperative House-Brackmann grade higher than I (48 of 102 patients [47%]) (odds ratio, 1.13; 95% CI, 1.04-1.23). Following salvage microsurgery, tumor growth–free survival rates at 1, 3, and 5 years were 97% (95% CI, 94%-100%), 93% (95% CI, 87%-99%), and 91% (95% CI, 84%-98%), respectively.ConclusionsIn this cohort study, more than half of patients who received salvage microsurgery following primary SRS/FSRT underwent less than GTR or experienced some degree of facial paresis long term. These data suggest that the cumulative risk of developing facial paresis following primary SRS/FSRT by the end of the patient’s journey with treatment approximates 2.5% to 7.5% when using published primary SRS/FSRT long-term tumor control rates.

OBJECTIVE Poor pain control has a negative impact on postoperative recovery and patient satisfaction. However, overzealous pain management, particularly with opioids, can confound serial neurological assessments, increase morbidity, and predispose patients to long-term dependence. Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in treating postoperative pain and can limit opioid intake, but their use has been limited in patients undergoing craniotomy for brain tumor resection due to concerns of an increased hemorrhage risk. Herein, the authors aim to 1) address the safety of NSAID use in the immediate postoperative setting and 2) determine whether NSAID administration decreases opioid use following craniotomy for tumor resection in adult patients. METHODS The authors conducted a retrospective cohort study of patients 18 years and older with an estimated glomerular filtration rate ≥ 60 ml/min/body surface area who had undergone craniotomy for tumor resection at their institution between 2019 and 2021. NSAID use in the first 48 hours following surgery was recorded. Primary outcomes were postoperative hemorrhage requiring a return to the operating room before hospital discharge and within 30 days of surgery. Secondary outcomes were more-than-minimal hemorrhage that did not require reoperation, acute kidney injury, and total opioid use within 48 hours after craniotomy. RESULTS Among 1765 reviewed patient records, 1182 were eligible for inclusion in this analysis. Amid these records were 114 patients (9.6%) who had received at least one dose of an NSAID within 48 hours of their craniotomy. Four (0.3%) patients experienced bleeding requiring a return to operating room, one of whom was from the NSAID-treated group (RR 3.12, 95% CI 0.33–29.77, p = 0.30). No significant difference in nonoperative intracranial hemorrhage (RR 1.34, 95% CI 0.54–3.35, p = 0.53), postoperative acute kidney injury, or clinically significant extracranial bleeding was found between the NSAID and no-NSAID groups. Patients in the NSAID group had significantly higher oral morphine equivalent use (median 68 vs 30, p < 0.001). CONCLUSIONS Postoperative NSAID use following craniotomy for tumor resection was not associated with an increased risk of hemorrhage requiring a return to the operating room. The authors noted higher opioid use in the patients treated with NSAIDs, which may reflect underlying reasons for the decision to treat patients with NSAIDs in the immediate postoperative period. These data warrant further investigation of NSAIDs as a safe, opioid-sparing postoperative pain management strategy in patients with normal kidney function who are undergoing intracranial tumor resection.

Abstract White matter dissection (WMD) involves isolating bundles of myelinated axons in the brain and serves to gain insights into brain function and neural mechanisms underlying neurological disorders. While effective, cadaveric brain dissections pose certain challenges mainly due to availability of resources. Technological advancements, such as photogrammetry, have the potential to overcome these limitations by creating detailed three-dimensional (3D) models for immersive learning experiences in neuroanatomy. Objective: This study aimed to provide a detailed step-by-step WMD captured using two-dimensional (2D) images and 3D models (via photogrammetry) to serve as a comprehensive guide for studying white matter tracts of the brain. One formalin-fixed brain specimen was utilized to perform the WMD. The brain was divided in a sagittal plane and both cerebral hemispheres were stored in a freezer at -20°C for 10 days, then thawed under running water at room temperature. Micro-instruments under an operating microscope were used to perform a systematic lateral-to-medial and medial-to-lateral dissection, while 2D images were captured and 3D models were created through photogrammetry during each stage of the dissection. Dissection was performed with comprehensive examination of the location, main landmarks, connections, and functions of the white matter tracts of the brain. Furthermore, high-quality 3D models of the dissections were created and housed on SketchFab®, allowing for accessible and free of charge viewing for educational and research purposes. Our comprehensive dissection and 3D models have the potential to increase understanding of the intricate white matter anatomy and could provide an accessible platform for the teaching of neuroanatomy.

OBJECTIVE Microvascular decompression (MVD) is a well-established and highly effective treatment option for hemifacial spasm (HFS). Lateral spread response (LSR) has been used as an intraoperative indicator of HFS resolution, with controversial reliability. The purpose of this study was to determine long-term outcomes of MVD for HFS and the role of LSR and other preoperative predictors. METHODS The authors conducted a cohort study of all patients treated with MVD for HFS at a single institution from January 1, 1998, to December 31, 2019. In addition to a retrospective chart review, all patients were contacted at the time of the study to provide informed consent and responded to a telephone survey to ascertain their current disease and medication status. Patients with at least 12 months of postoperative follow-up were included. Statistical testing included a Student t-test, Fisher’s exact test, logistic regression, and Cox proportional hazards analysis. RESULTS One hundred nineteen patients met study criteria; 41 (34%) had at least 10 years of clinical follow-up. HFS fully resolved in 93 (78%), symptoms subjectively improved in 11 (9%) and were unchanged in 15 (13%). Immediate postoperative HFS status did not correlate with long-term outcome (p = 0.13). Changes in LSR were not associated with outcome. Patients receiving neuromodulating agents had significantly longer preoperative duration of symptoms and were more likely to show persistent LSR intraoperatively. HFS recurrence was associated with younger age at the time of surgery but not with intraoperative LSR resolution. CONCLUSIONS This study demonstrated that MVD for HFS is highly effective for most patients. Neither intraoperative LSR change nor immediate postoperative status was predictive of long-term outcomes.

AbstractHemifacial spasm is a neuromuscular disorder caused by compression of the facial nerve at the nerve root entry zone, often due to ectatic or aberrant vasculature. Pathologic compression of the nerve–brainstem interface results in involuntary, paroxysmal contractions of ipsilateral facial muscles that may cause considerable impairments in quality of life. For those with severe symptoms, have positive imaging demonstrating vascular compression, or who fail other management modalities,1 2 3 4 microvascular decompression offers potential definitive treatment.5 6 Traditionally, nonabsorbable packing agent is used to pack between the nerve and offending vascular structure. However, for large and more complex arterial structures, simple nonabsorbable padding is often not sufficient.In this operative video, we demonstrate microvascular decompression for intractable hemifacial spasm in a 52-year-old female using a specialized sling tacked to the petrous dura for management of a large, ectatic vertebral artery. Following a standard left retrosigmoid craniotomy, an atheromatous ectatic vertebral artery was identified. We fashioned a bovine pericardium sling around the vessel and used a permanent aneurysm clip to secure it to an incision portion of petrous dura. We subsequently identified potential additional facial nerve root compression by anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) branches, which were elevated and secured using Teflon felt packing. Following elevation of all three vessels, the lateral spread response resolved. At 2 weeks postoperatively, the patient reported substantial relief in her hemifacial spasms and endorsed highly improved quality of life.

Objective The treatment paradigm of vestibular schwannoma (VS) focuses on preservation of neurologic function, with small tumors increasingly managed with active surveillance. Often, tumor size and hearing outcomes are poorly correlated. The aim of the current work was to describe the natural history of hearing among patients with nongrowing VS during observational management. Study Design Historical cohort study. Patients Adults with sporadic VS. Intervention Wait-and-scan management. Main Outcome Measure Maintenance of serviceable hearing (SH) after diagnosis. Results Among 228 patients with nongrowing VS, 157 patients had SH at diagnosis. Rates of maintaining SH (95% CI; number still at risk) at 1, 3, and 5 years after diagnosis were 94% (89–98; 118), 81% (74–89; 65), and 78% (71–87; 42), respectively. Poorer hearing at diagnosis (hazard ratio [HR] per 10 dB hearing level increase in pure-tone average of 2.51, p < 0.001; HR per 10% decrease in word recognition score of 1.70, p = 0.001) was associated with increased likelihood of developing non-SH during observation. When controlling for baseline hearing status, tumors measuring 5 mm or greater in the internal auditory canal or with cerebellopontine angle extension were associated with significantly increased risk of developing non-SH (HR, 4.87; p = 0.03). At 5 years after diagnosis, 95% of patients with nongrowing intracanalicular VS measuring less than 5 mm maintained SH. Conclusions Hearing worsens during periods of nongrowth in sporadic VS. Patients with small (<5 mm) intracanalicular tumors demonstrate robust maintenance of SH over time, reinforcing the consideration of initial observation in this patient subset.

Abstract OBJECTIVE This study aimed to analyze the hemorrhagic risk of melanoma brain metastases following SRS. METHODS A retrospective analysis was conducted using a prospective institutional database between 1990 and 2021. Lesional hemorrhage was categorized as definite or possible, and hemorrhage severity was graded using CTCAE. RESULTS The study identified 291 patients with 1083 lesions. The mean age of patients was 60 ± 15 years, with 61% being male. Median follow-up was 11 months, corresponding to 581 patient-years. Among the patients, 82 (28%) experienced 135 lesional hemorrhages (13%). Of these, 88 lesions in 61 patients were grade 1-2 hemorrhages, 42 lesions in 25 patients were grade 3, and five lesions in five patients progressed from grade 1 to 3. Surgical intervention was required for 17 lesions (2%) in 16 patients (5%). Lesional hemorrhage was associated with radiosurgery performed between 2015 and 2021 (OR, 0.373; 95% CI, 0.231-0.60; p &lt; 0.001), increasing marginal dose (OR, 0.89; 95% CI, 0.82-0.98; p = 0.017), antiplatelet use (OR, 0.192; 95% CI, 0.082-0.45; p &lt; 0.001), and WBRT (OR, 0.51; 95% CI, 0.330-0.77; p = 0.0017). The cumulative lesional hemorrhage risk reached 17–20% at 36 months following radiosurgery, with 95-96% of hemorrhages occurring within the initial year. Median OS was 11 months (95% CI, 9-13 months). Patients who received radiosurgery between 2015 and 2021 exhibited a median OS of 17 months (95% CI, 10-24 months; p &lt; 0.001), while those without hemorrhage had a median OS of 12 months (95% CI, 10-14 months; p = 0.054). CONCLUSIONS Definitive hemorrhage risk was 17% for melanoma brain metastases after SRS within the first three years, with 95% of lesional hemorrhages occurring within the initial year. Surgical intervention was necessary in 5% of patients. Hemorrhage risk and overall survival improved after 2015.

OBJECTIVE Arginine vasopressin deficiency (AVD) following neurosurgical procedures for pituitary disorders is common and can delay discharge. Copeptin, a stable surrogate marker of arginine vasopressin, may predict postoperative AVD. The authors’ aim was to assess the optimal postoperative sampling time and cut-point concentration of copeptin to predict the development of postsurgical AVD. METHODS Adults without preexisting AVD who were undergoing surgery for a pituitary lesion between February 2020 and April 2022 were eligible for study inclusion. Two samples were drawn from each patient postoperatively to assess the copeptin concentration using an immunofluorescent assay. Samples were denoted as "early" (within 6 hours of extubation) or "postoperative day 1" (POD1; within 10–30 hours of extubation). Patients were evaluated for the development of AVD. RESULTS One hundred ninety-two patients (54.2% female) with a median age of 54.5 years (IQR 39.8–67.0 years) were included in the study. The median copeptin concentration at both time points was significantly lower in those with AVD (transient or permanent; n = 22, 11.5%) than in those without (early: 4.9 vs 18.7 pmol/L, p < 0.001; POD1: 3.4 vs 4.9 pmol/L, p < 0.001) but did not differ in those who developed transient versus permanent AVD. The optimal copeptin cut point for the prediction of AVD was < 8.5 pmol/L for early samples (sensitivity 0.70, specificity 0.80, positive predictive value [PPV] 0.29, negative predictive value [NPV] 0.96) and < 4.3 pmol/L for POD1 samples (sensitivity 0.82, specificity 0.63, PPV 0.22, NPV 0.96). In early samples, a copeptin cutoff of 22.9 pmol/L increased the sensitivity for the detection of AVD to 95% with an NPV of 99%. The proportion of patients who had AVD was higher (60.0% vs 8.8%, p < 0.001) and the copeptin concentration lower (early: 4.3 vs 17.0 pmol/L, p < 0.001; POD1: 2.7 vs 4.9 pmol/L, p < 0.001) among those who had undergone surgery for a craniopharyngeal duct pathology versus a pituitary adenoma. Although copeptin was lower in patients with persistent Cushing’s disease than in those in remission, the difference did not reach statistical significance (early p = 0.11, POD1 p = 0.52). Furthermore, the copeptin concentration could not predict the development of syndrome of inappropriate secretion of antidiuretic hormone. Patients without AVD who had received stress dose steroids intraoperatively had lower median early copeptin (11.7 vs 19.1 pmol/L, p = 0.027). CONCLUSIONS In early postoperative copeptin samples, the optimal copeptin cut point for AVD diagnosis was < 8.5 pmol/L, and a level > 22.9 pmol/L had predicative utility in excluding AVD. Caution should be used when interpreting copeptin results, as patients administered glucocorticoids intraoperatively without AVD had lower median copeptin concentrations.