Facial Nerve Outcomes following Subtotal, Near-Total, and Total Vestibular Schwannoma Resection: A Retrospective Analysis of the British Skull Base Society National Vestibular Schwannoma Database

Aims: Macroscopic “gross total resection” was the traditional goal for patients undergoing resection of vestibular schwannoma. There has been a shift toward “subtotal” resection in an attempt to mitigate the risk of cranial nerve injury, reserving radiotherapy and/or revision surgery for growing residual tumors. The decision for subtotal versus total resection may be made preoperatively. Additionally, “near-total” resection has been acknowledged as microscopic residual disease, the decision of which is often made intraoperatively when cranial nerve risk is encountered. In recent years, some centers have advocated for planned subtotal resection, citing overall lower risks of facial palsy; however, to date, no robust comparison of facial nerve outcomes has been performed. This study reviews a United Kingdom national, multicenter registry to explore the demographic and disease features of extent of resection and compare cranial nerve outcomes.

Methods: A retrospective review of the British Skull Base Society (BSBS) National Vestibular Schwannoma Database performed over a 19-year period from 2004 to 2023. Cases were included when surgery was the initial treatment modality, preoperative intracranial tumor diameter (ICTD) was ≥ 15 mm, preoperative house Brackman was grade I, and either 5 years of follow-up (or 2 years with exit MRI for total resection was recorded. NF2 was excluded.

Results: A total of 18,247 cases were retrieved from the database; 2,824 were identified as undergoing surgery. A total of 200 cases met the study inclusion criteria: 14.5% underwent subtotal resection, 39.5% near-total, and 46.0% total resection. Compared to total, those undergoing subtotal resection were older, had a larger preoperative ICTD and were more commonly performed via a retrosigmoid approach. The risk of facial weakness (≥ HB II) was 32.0% for the entire cohort. The risk of poor facial nerve outcome (HBIII–VI) was twice as common in the subtotal group (20.7%) compared to the near-total (10.1%) and total group (9.5%), although not statistically significant. Ordinal logistic regression modeling could significantly predict House Brackman facial nerve outcomes using age, preoperative ICTD and extent of tumor resection as predictive variables. Of these, only age was a significant predictor, with the risk of facial weakness increasing with age. 27.6% of those undergoing surgical resection proceeded to post-operative radiotherapy, while 7.1% required revision surgery.

Discussion: A powerful confounding bias in this study is the acknowledgement of whether a planned preoperative decision or an intraoperative assessment and decision for extent of resection occurs. Furthermore, it identifies the ambiguity that can surround the classification of the extent of resection. Discussion of these results reveals factors that may lead to decisions regarding the extent of resection and identifies where future improvements in study design are required to answer this important clinical question.

 

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Artikel online veröffentlicht:
07. Februar 2025