Characterization and Predictive Factors of Peritumoral Radiographic Changes in Operative Vestibular Schwannomas: A Comprehensive Multi-Institutional Study

Introduction: Peritumoral radiographic changes remain an under-characterized event in vestibular schwannoma (VS) management. This large-scale, multi-institutional study uniquely evaluates radiographic changes occurring anytime during observation or treatment of VS patients–including diffusion restriction, T2 hyperintensity, parenchymal shrinkage, or encephalomalacia–leveraging data from three large tertiary care centers in New England. Objectives: To delineate clinical, demographic, and tumor-specific factors associated with peritumoral radiographic changes in operative VS patients, identify independent predictors, and assess their impact on postoperative neurological function and complication rates. Methods: A retrospective review of 2,139 operative VS patients from the MGB system databases was conducted. Peritumoral radiographic changes were identified based on criteria including diffusion restriction, T2 hyperintensity, parenchymal shrinkage, or encephalomalacia on MRI during any stage of observation or treatment. Patients were divided into presence ( n = 514) and absence ( n = 1,625) groups. The vast majority were asymptomatic and incidentally discovered. Baseline demographics, lesion characteristics, laboratory data, operative approaches, and functional outcome measures (Modified Rankin Scale [MRS], Glasgow Outcome Scale Extended [GOSE], and Barthel Index) were collected. To mitigate type 1 error inflation, no t -tests or chi-square tests were performed; logistic regression models were used to ascertain predictors of radiographic changes. Results: The radiographic changes group demonstrated a younger mean age (48.4 ± 14.6 versus 50.0 ± 12.7 years) and larger mean lesion size (24.2 ± 9.2 versus 22.4 ± 10.7 mm). Retrosigmoid craniotomy was significantly more common in radiographic change cases (89.5% versus 71.9%), while gross total resection rates were notably lower (61.2% versus 80.7%), suggesting more complex surgical courses in radiographic change patients. Importantly, cystic schwannoma morphology conferred a greater than 2-fold increased risk of radiographic changes (OR 2.13, 95% CI 1.19–3.81, p = 0.011). Similarly, abnormal preoperative nutritional status, defined by laboratory parameters, was a significant independent predictor (OR 2.26, 95% CI 1.27–4.03, p = 0.006). While age, BMI, smoking history, and high-riding jugular bulb anatomy did not reach statistical significance, trends suggested complex multifactorial risk profiles. Postoperatively, patients with radiographic changes experienced substantially higher rates of radiographic tumor recurrence (23.7% versus 6.3%) and hydrocephalus (24.5% versus 10.2%), alongside increased cerebrospinal fluid leak incidence (8.6% versus 4.9%). Functional outcome assessment revealed worsened final MRS and GOSE scores in the radiographic changes cohort, indicating sustained neurological deficits. Notably, Barthel Index scores, reflecting activities of daily living, were also lower in these patients, underscoring the clinical impact of these ischemic events on patient independence. Conclusion: This multi-institutional investigation across the MGB system identifies cystic tumor morphology and abnormal nutritional status as key predictors of peritumoral radiographic changes in operative VS patients. The changes, radiologically confirmed via diffusion-weighted imaging and T2 sequences, correlate with increased postoperative complications and worse neurological outcomes. These findings advocate for heightened preoperative assessment and optimization, particularly nutritional evaluation, and suggest potential benefits from tailored surgical strategies to mitigate risk. Future prospective studies should explore pathophysiological mechanisms and interventional approaches to improve outcomes in this high-risk cohort. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany