Facial Nerve Outcomes Following Microsurgical Resection of Large Cerebellopontine Angle Tumors: Experience From a Tertiary Care Center in Pakistan

Background Cerebellopontine angle (CPA) tumors present surgical challenges due to their proximity to the facial nerve. Despite preservation efforts, facial nerve paresis is a major issue. This study aims to identify key factors affecting facial nerve preservation during microsurgical resection of large CPA tumors in a low-and middle-income countries (LMIC) setting. Methods This retrospective cross-sectional study, conducted at Aga Khan University, included patients who underwent microsurgical resection of large (>3 cm) CPA tumors with House-Brackmann (HB) grades 1–4. Postoperative facial nerve function was assessed using the HB grading system. Data was extracted from medical records and analyzed using SPSS 22. Results This study analyzed 95 patients (M:F=1:1.16, mean age 44.24±13.71 years) with CPA tumors who underwent microsurgical resection. Common presenting complaints included a complete hearing loss (57.9%), headache (52.6%), and abnormal gait (40%). Preoperative facial nerve function was normal (HB grade I) in 75%, with 19%, 7%, and 2% having HB grades II, III, and IV, respectively. Schwannoma (69.5%), meningioma (16.8%), and epidermoid cyst (10.5%) were the most common diagnoses. Postoperative preservation of facial nerve function was achieved in 73.7% of patients. At six months, HB grades I and II were observed in 64% and 11.5%, respectively, while none had complete facial nerve palsy. On univariate analysis, larger tumor size and higher HB grade correlated with worse facial nerve outcomes (p=0.02). Complications were more frequent in patients with worsened outcomes (72% vs. 38.6%, p=0.004). However, in multivariate analysis, only preoperative HB grade was identified as a predictor. Conclusion Facial nerve preservation during CPA tumor resection is influenced by intrinsic tumor characteristics, surgical complexity, and patient-specific factors. Detailed preoperative counseling is crucial to set realistic expectations.