Salvage Microsurgery Following Failed Primary Radiosurgery in Sporadic Vestibular Schwannoma

Abstract

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.

Assessing Facial Nerve Function After Salvage Microsurgery for Vestibular Schwannoma—Reply

“…In Reply We appreciate the complementing insights offered by Di Stadio et al in their recent correspondence regarding our multicenter study examining clinical outcomes after salvage microsurgery for vestibular schwannoma failing primary radiosurgery . We share similar feelings regarding the limitations of the House-Brackmann grading scale and other gross scales for assessing facial nerve function.…”

Assessing Facial Nerve Function After Salvage Microsurgery for Vestibular Schwannoma

“…These data from this study have important implications for shared decision-making. The authors note that with primary microsurgery, the risk of facial paresis is upfront; they also consider a role for early intervention for tumors with cerebellopontine angle extension, acknowledging the diagnostic complexity from postradiosurgical tumor pseudoprogression.…”

“…To the Editor We read with interest the article by Marinelli et al, which identified persistent facial palsy in more than half of patients undergoing salvage microsurgery for residual or recurrent schwannoma after failed primary radiosurgery. The inflammatory changes, scarring, and vascular alterations from radiation can impede complete tumor removal and increase risk of complications, including impaired facial nerve injury.…”