Pre-operative blood-based inflammatory indices and long-term facial nerve outcomes following vestibular schwannoma resection.

OBJECTIVE: Inflammation contributes to tumor pathogenesis and growth in vestibular schwannoma (VS) patients, but associations with facial nerve outcome following surgical resection remain unclear. We aimed to evaluate whether blood-based inflammatory indices are associated with postoperative facial nerve outcomes following VS resection. PATIENTS AND METHODS: This retrospective cohort study included adult VS patients who consecutively underwent microsurgical resection at our institution between July 2016 and July 2024. Patients with neurofibromatosis, previous radiotherapy or resection, baseline facial weakness, and inadequate followup were excluded. The neutrophil-to-lymphocyte ratio (NLR) and other inflammatory indices were calculated at several timepoints. Multivariable logistic regression was used to evaluate associations with poor facial nerve outcome (House-Brackmann grade > 2) at last followup and with recovery of facial nerve function. RESULTS: Among 396 patients, favorable facial nerve outcome (HB ≤ 2) was achieved in 315(80%) patients. A higher preoperative NLR was independently associated with poor long-term facial nerve outcome while adjusting for tumor size (OR = 1.10 [1.01–1.20], p = 0.028). A total of 162 patients developed facial nerve weakness (HB > 2) postoperatively, among which 81(50%) achieved recovery. A higher preoperative NLR was independently associated with non-recovery (OR = 0.82 [0.67–0.99], p = 0.035). Optimal discriminating cutpoints of preoperative NLR for facial nerve outcome and recovery were 1.62 and 2.02, respectively. CONCLUSION: Preoperative NLR may represent a biomarker for long-term facial nerve outcome following microsurgical resection of VS. This may be related to greater tumor adherence and a more vigorous inflammatory response to iatrogenic facial nerve injury. CLINICAL TRIAL NUMBER: Not applicable. This study does not constitute a clinical trial.