2025 Proffered Presentations
S269: 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.
Nathan Creber, FRACS, PhD1; Samuel Mackeith, FRCS2; Rajeev Mathew, FRCS, PhD2; Charlotte Hammerbeck-Ward, FRCS, PhD3; Simon Lloyd, FRCS4; James Tysome, FRCS, PhD5; 1Royal Prince Alfred Hospital Sydney, Australia; 2Oxford University Hospitals NHS Foundation Trust, UK.; 3University Hospitals Sussex NHS Foundation Trust, UK.; 4Manchester University Hospital NHS foundation Trust, UK.; 5Cambridge University Hospitals NHS Foundation Trust, UK.
Aims: Macroscopic “gross total resection” was the traditional goal for patients undergoing resection of vestibular schwannoma. There has been a shift towards “subtotal” resection in an attempt to mitigate the risk of cranial nerve injury, reserving radiotherapy and/or revision surgery for growing residual tumours. The decision for subtotal Vs 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 centres 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, multicentre 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, pre-operative intracranial tumour diameter (ICTD) was ≥ 15mm, preoperative house Brackman was grade I, and either 5 years follow-up (or 2 years with exit MRI for total resection was recorded. NF2 was excluded.
Results: 18247 cases were retrieved from the Database, 2824 identified as undergoing surgery. 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 pre-operative 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 modelling could significantly predict House Brackman facial nerve outcomes using age, preoperative ICTD and extent of tumour 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.