Faculty Bibliography

Stereotactic radiosurgery evolved from the desire to achieve highly precise and accurate target ablation using radiation energy. Over the past 3 decades, the range of indications for stereotactic radiosurgery has expanded significantly, making it a valuable treatment option-and often a first-line approach-for various intracranial conditions, including benign and malignant brain tumors, vascular malformations, and functional disorders. This narrative review offers a comprehensive, yet not exhaustive, overview of the current evidence, technical considerations, and areas of nuance and controversy regarding these indications and dose selection. It serves as a quick reference guide for neurosurgeons and radiation oncologists working in this field. In addition, tables are included that detail the indications, expected results, dose prescriptions, and anticipated outcomes, assisting clinicians in both clinical settings and procedural planning.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Pediatric large-volume brain arteriovenous malformations (AVMs) carry a substantial lifelong hemorrhage risk, neurological symptoms, and treatment morbidity. Single-session stereotactic radiosurgery (SRS) is often unsuitable due to constraints on dose-volume toxicity. Volume-staged SRS (VS-SRS) enables sequential dosing of large nidus volumes, potentially enhancing safety while maintaining efficacy. Evidence in children remains limited. We aimed to evaluate outcomes of VS-SRS for large AVMs in pediatric patients. METHODS:A multicenter retrospective cohort was assembled from 21 centers, including patients aged younger than 21 years treated with VS-SRS for AVMs >10 cm3. Clinical and radiological end points included obliteration, hemorrhage, and permanent symptomatic radiation-induced changes (RIC). RESULTS:A total of 103 patients were included (median age 14 years; IQR, 12-17). The median nidus volume at first stage was 18.2 cm3 (IQR, 12.3-25.6). Median prescription dose per stage was 17 Gy (IQR, 16-18). The median clinical follow-up from the first stage was 57.5 months (IQR, 25-138). Obliteration occurred in 42 of 103 patients (40.8%), with actuarial rates of 6.9% (95% CI: 2.8-14) at 3 years and 29% (95% CI: 20-39) at 5 years. Hemorrhage occurred in 17 of 103 patients (16.5%) during follow-up, and permanent RIC was observed in 9 of 103 patients (8.7%). CONCLUSION/CONCLUSIONS:VS-SRS is a reasonably safe, selected option for pediatric large-volume AVMs when microsurgical or endovascular cure is not feasible or prudent. Delivering ≥17 Gy per stage while limiting each treatment volume to <15 cm3 supports durable nidus control with acceptable toxicity. VS-SRS represents a key modality in multidisciplinary management of this historically difficult-to-treat population.

INTRODUCTION/BACKGROUND:Subway-related trauma is an understudied category of urban injury. Prior work has focused on high-acuity train-contact events, with less attention to more common mechanisms and the roles of psychiatric illness and substance use. We analyzed a large contemporary cohort to define epidemiology, injury patterns, and outcome predictors across the full spectrum of subway trauma. METHODS:We performed a retrospective cohort study of adults presenting with subway-related injury to a Level I trauma center (2018-2024). Registry data and manual chart review captured demographics, mechanisms, comorbidities, intoxication, injury severity, and outcomes. Injuries were categorized using validated natural language processing. Multivariable logistic regression identified predictors of train-contact mechanism, major trauma (ISS ≥ 15), TBI, and assault. RESULTS:Among 809 patients, median age was 50 years and 81.2% were male. Falls were most common (57.2%), followed by train contact (16.8%) and assault (16.7%). Median ISS was 9, with 25.0% sustaining major trauma. TBI occurred in 40.5% and did not differ by mechanism. Train contact was the most severe mechanism and the only independent predictor of major trauma (aOR 5.08). Psychiatric diagnosis (aOR 1.59) and acute intoxication (aOR 1.69) independently predicted train contact, while intoxication predicted TBI (aOR 1.66). Psychiatric illness and substance use disorder were associated with longer hospitalization independent of injury severity. Assault exposure varied by race/ethnicity. CONCLUSION/CONCLUSIONS:Most subway injuries result from falls rather than intentional mechanisms. Train contact drives severity, while intoxication increases TBI risk. Psychiatric and substance use comorbidities prolong hospitalization, supporting routine behavioral health screening and targeted prevention strategies.

INTRODUCTION/BACKGROUND:Essential tremor is a common movement disorder that can cause substantial functional disability when symptoms become medically refractory. Stereotactic radiosurgery (SRS) is a minimal access treatment strategy for tremor control, but multicenter outcome data remain limited. METHODS:We performed a retrospective multi-institutional cohort study of 232 stereotactic radiosurgical thalamotomy procedures for medically refractory essential tremor. The median age at treatment was 76.0 years, median tremor duration was 17.0 years, median margin dose was 70.0 Gy, and median maximum dose was 140.0 Gy. The primary endpoint was clinically meaningful tremor improvement. Secondary endpoints included tremor arrest, recurrence, adverse radiation effects (AREs), and change in Fahn-Tolosa-Marín (FTM) scores. Logistic regression was used to evaluate outcome predictors. RESULTS:Significant tremor improvement was observed in 92.1% of patients, with a median time to improvement of 4.0 months. Complete tremor relief occurred in 26.1%. Symptomatic AREs occurred in 4.3%. Tremor recurrence was noted in 12.4% at median follow-up of 2 years. Among procedures, mean unilateral hand FTM score improved from 12.53 to 5.07, corresponding to a mean improvement of 7.46 points (p < 0.001). Significant improvement was also observed across tremor, writing, drawing, and drinking sub scores (all p < 0.001). On multivariable analysis, a maximum lesion dose ≥ 140 Gy was independently associated with greater odds of clinical benefit (OR 3.44, p = 0.019). CONCLUSION/CONCLUSIONS:In this multi-institutional cohort, SRS was associated with high rates of clinically meaningful tremor improvement, significant functional improvement, and durable tremor control in medically refractory essential tremor.

BACKGROUND:Parkinson's disease management is often complicated by motor fluctuations and dyskinesia. Although deep brain stimulation addresses these symptoms, its use is limited by invasiveness, potential device failure, and the need for ongoing maintenance. Magnetic resonance-guided focused ultrasound (MRgFUS) provides incisionless, image-guided ablation as an alternative. However, the benefits and harms of staged, bilateral MRgFUS pallidothalamic tractotomy have not been evaluated systematically in prospective multicentre studies. METHODS:In this prospective, multicentre, single-arm study, adults with idiopathic, levodopa-responsive Parkinson's disease and motor complications (Movement Disorders Society Unified Parkinson's Disease Rating Scale [MDS-UPDRS] part IV item 4.2 or 4.4 score ≥2) were enrolled at nine investigational centres (six in the USA, two in Spain, and one in Taiwan). Participants underwent unilateral MRgFUS pallidothalamic tractotomy to the symptom-dominant side. Contralateral pallidothalamic tractotomy followed a minimum of 6 months later for participants meeting prespecified criteria. The primary efficacy endpoint was percent change from baseline to 3 months after the second procedure in the summed MDS-UPDRS part III off-medication upper and lower extremity (ULE) motor scores. Safety outcomes were incidence, severity, and persistence of treatment-related adverse events in the 12 months after each procedure. Safety and efficacy of unilateral treatment were evaluated in the unilateral intention-to-treat (ITT) and safety populations, defined as all patients receiving one or more sonications during the first procedure. The primary outcome and safety of bilateral treatment were evaluated in the bilateral modified ITT (mITT) and safety populations, which required one or more sonications during the second procedure, a baseline motor assessment, and at least one post-bilateral motor assessment. This trial is registered at ClinicalTrials.gov, NCT04728295 and is active, not recruiting. FINDINGS/RESULTS:Between July 12, 2021, and Nov 1, 2023, 54 patients received unilateral treatment and 40 proceeded to bilateral treatment (63 [67%] were male and 31 [33%] were female) and were included in the primary analysis; 36 completed 12-month follow-up after the second procedure. Median bilateral ULE motor scores decreased from 33·0 points (IQR 28·0-40·5) at baseline to 21·0 points (15·0-25·5) at month 3 post-bilateral treatment, a median within-patient change of 10·5 points (5·7-20·0), representing a 32% (18-52) improvement (p<0·0001). Benefits became apparent within 1 month of the first procedure and lasted through to 12 months after the second procedure. Treatment-related adverse events occurred in 21 (39%) of 54 patients after unilateral treatment; one (2%) had a persistent moderate adverse event at 6 months. After bilateral treatment, 22 (55%) of 40 patients had treatment-related adverse events; ten (25%) had persistent moderate or severe adverse events at 12 months, mainly affecting speech, gait, and balance. One (3%) patient developed severe persistent anarthria. INTERPRETATION/CONCLUSIONS:Unilateral MRgFUS pallidothalamic tractotomy demonstrated safety and efficacy for Parkinson's disease motor complications; however, bilateral treatment offered small motor gains while increasing persistent moderate or severe adverse events. Post-bilateral treatment complications in speech, gait, and balance are consistent with historical data for bilateral ablative procedures for movement disorders. Although unilateral MRgFUS pallidothalamic tractotomy was beneficial in our study, bilateral procedures demand rigorous patient selection and counselling regarding cumulative risks. FUNDING/BACKGROUND:Insightec.

BACKGROUND:Middle meningeal artery embolization (MMAE) has emerged as a treatment for chronic subdural hematoma (cSDH), but comprehensive real-world safety data remain limited. METHODS:We performed a multicenter retrospective analysis of 1781 consecutive patients undergoing MMAE for cSDH (2019-2025). The primary outcome was any procedure-related complication within 30 days. Inverse probability of treatment weighting (IPTW) assessed the association between technical success and complications, adjusting for demographic, clinical, and procedural confounders. RESULTS:Mean age was 72.8 ± 12.4 years; 68.1% were male. The 30-day complication rate was 5.1% (91/1781; 95% CI, 4.1-6.2). In-hospital mortality was 2.9% (47/1625). Technical success was achieved in 97.5% (1505/1543). Among documented complications, thromboembolic events were most common (37.2%; 32/86), followed by hemorrhagic complications (23.8%; 20/84) and access-site hematoma (10.4%; 8/77). Among patients with classifiable symptom status, 80.6% of complications were symptomatic, yielding an overall symptomatic complication rate of 3.0%. Neurological deterioration occurred in 27.1% (248/915). Among 1552 patients with documented surgical approach, complication rates were similar between surgery plus embolization (4.9%; 34/690) and embolization alone (5.2%; 45/860; OR, 0.94; 95% CI, 0.59-1.48; p = 0.79). After IPTW adjustment, technical success was associated with an 86% reduction in complication odds (OR, 0.14; 95% CI, 0.05-0.40; p < 0.001). CONCLUSIONS:In this large multicenter cohort, MMAE was associated with a 5.1% complication rate. Technical success was the strongest protective factor. Embolization with or without surgery showed equivalent safety profiles.

BACKGROUND:Population-based studies have linked progestin exposure to increased meningioma risk. However, the molecular basis of meningiomas associated with depot medroxyprogesterone acetate (DMPA) - a common injectable contraceptive-remains undefined. METHODS:We performed an integrated clinicopathologic and genomic analysis of meningiomas from 10 women with long-term DMPA exposure. Tumors underwent histopathological analysis, targeted sequencing, and DNA methylation profiling. Data were integrated with reference cohorts (Baylor and Heidelberg) and analyzed through classifier assignment, consensus clustering, copy number analysis, differential methylation testing, and dimensionality reduction. RESULTS:DMPA-associated meningiomas were all newly diagnosed, WHO grade 1 tumors with a predilection for the anterior and central skull base (n = 6). Nine patients harbored multiple meningiomas. Four experienced regression of untreated meningiomas following DMPA cessation, while five demonstrated stabilization. Histopathology demonstrated relative overrepresentation of metaplastic morphology, an uncommon meningioma subtype. All DMPA-associated meningiomas mapped to benign molecular groups, and most exhibited low copy number alteration burden. Targeted sequencing revealed enrichment for TRAF7 mutations (n = 5), with no NF2 mutations detected. Eight tumors shared consensus cluster identity, with cohesive grouping on principal component analysis and t-distributed stochastic neighbor embedding. No differential methylation was identified at the progesterone receptor locus. CONCLUSIONS:DMPA-associated meningiomas represent a recognizable phenotype within the broader NF2-wildtype/TRAF7-enriched spectrum of benign meningiomas, characterized by chromosomal stability, a shared methylation profile, tumor multiplicity, and regression or stabilization following DMPA cessation. While derived from a small single-institution cohort, these findings provide a molecular framework for understanding progestin-associated meningioma biology, re-interpreting epidemiologic literature, and informing population-level risk stratification.

OBJECTIVE:Diagnostic and treatment delays in infantile epileptic spasms syndrome (IESS) increase the risk of poor neurodevelopmental outcomes. Early clinical recognition of IESS is essential, especially in regions lacking expedited access to electroencephalograms (EEG). This study aimed to determine clinicians' accuracy at recognizing infantile epileptic spasms (ES) based on smartphone videos, and the impact of brief IESS education on accuracy, diagnostic confidence, and willingness to treat without EEG. METHODS:This multicenter prospective cohort study took place over seven sessions globally from 2022 to 2023. Smartphone videos of children from the US and South Africa with EEG-confirmed diagnoses of IESS (6 videos) and non-epileptic ES-mimickers (3 videos) were obtained. Staff physicians and trainee participants from multiple subspecialties worldwide viewed videos three times: (1) baseline viewing, (2) after brief IESS training, and (3) with clinical history. Surveys on diagnosis and management were completed after each viewing. RESULTS:Of 187 participants who attended a session and initiated a survey, 180 (80 trainees [44%]) met the inclusion criteria. Initial diagnostic accuracy averaged 64% (95% confidence interval [CI]: 62-66%) and improved to 72% (69-74%) after IESS training and clinical history (V + T + CHx). Area under the curve for diagnostic performance of smartphone videos was 0.80 (0.78-0.82), and sensitivity was 0.85 (0.83-0.88) after V + T + CHx. The odds of making a correct diagnosis increased by 86% (OR 1.86, CI 1.59-2.18, p < 0.001) after V + T + CHx. Diagnostic confidence and clinician comfort level treating ES without EEG also improved significantly after V + T + CHx (by 0.36 points and 0.45 points, respectively, on 5-point Likert scales, p < 0.001). Diagnostic accuracy correlated strongly with increased diagnostic confidence and increased clinician comfort level managing patients without an EEG (p < 0.001). Staff physicians had a 24% higher likelihood of making a correct diagnosis than trainees. SIGNIFICANCE/CONCLUSIONS:Smartphone videos, especially when enhanced by brief IESS training, can facilitate triage and early identification of infantile ES, reducing diagnostic delays in this time-sensitive condition. PLAIN LANGUAGE SUMMARY/CONCLUSIONS:Infantile epileptic spasms syndrome is associated with severe developmental impacts, which can be worsened by delayed treatment. Rapid diagnosis is critical, especially in resource-limited settings lacking specialists and timely access to diagnostic tests. Our study found that clinician participants identified epileptic spasms, the hallmark seizure type of this condition, based on video alone with moderately high accuracy, and accuracy improved after education and clinical information. Thus, smartphone videos, particularly when enhanced by brief training, may be an effective tool to triage movements concerning for epileptic spasms, potentially improving resource allocation and reducing diagnostic delays in this urgent childhood epilepsy condition.

STUDY DESIGN/METHODS:Retrospective multicenter registry. OBJECTIVE:To establish a multidimensional definition of surgical success in ASD surgery and evaluate achievement rates across diverse patient subgroups. SUMMARY OF BACKGROUND DATA/BACKGROUND:Adult spinal deformity (ASD) encompasses diverse deformity types, disability levels, and treatment options. Optimal surgery aims in part to improve function, reduce radicular pain, and minimize revisions. Despite some studies considering combined outcomes, comprehensive multifactorial evaluation remains limited. METHODS:Success was assessed across disability (2-year ODI ≤20 or ∆ODI >14), radicular pain (NRS Leg ≤3 or ∆NRS Leg >3), and reoperation (no mechanical/neurologic revision). Patients were categorized by preoperative high disability (ODI >40) and/or high pain (NRS Leg >5). Individual and composite success rates were compared across preoperative deficits and deformity types. Satisfaction and treatment repetition willingness were analyzed by success achievement. RESULTS:Of 1,504 patients, 1,084 (71.9%) completed 2-year follow-up (median age 64 years, 75.4% female, 50.7% prior surgery). Median preoperative scores: ODI 44, NRS Back 8, NRS Leg 5. Preoperatively, 40.7% had combined high disability and pain, 21.6% high disability only, 13.5% high pain only, and 20.2% neither. At 2 years, success rates were 60.9% for disability, 64.8% for leg pain, 81.2% for revision avoidance, and 40.5% composite. Composite success was highest without preoperative deficits (59.4%), intermediate with isolated deficits (38.0% high disability, 43.8% high pain), and lowest with combined deficits (32.2%). Severe coronal deformities achieved highest composite success (51.7%) versus 32.0%-41.3% for other types. Composite success strongly correlated with satisfaction (87.2%) and willingness to repeat treatment (94.4%). CONCLUSIONS:Success in ASD surgery should reflect both improvement and final outcomes. Composite success measures provide more comprehensive surgical assessment than single metrics. By identifying patient characteristics associated with higher success rates, this framework informs evidence-based patient selection, enables realistic preoperative counseling, and guides outcome-driven surgical planning.