Surgical Outcomes After Total or Subtotal Resection of Large Vestibular Schwannoma: A Single-Institution Experience

BACKGROUND: Patients with large vestibular schwannomas have various surgical outcomes. The aim of this study is to evaluate facial nerve outcome and surgical complications in patients who underwent total and subtotal resection. METHODS: Between October 2008 and September 2020, 72 patients underwent surgery in Rajavithi Hospital. Of these, 48 had total or subtotal resection. We classified these participants into two groups: VS ≥3 cm (Group A, n=30); and VS <3 cm (Group B, n=18). Both groups were compared in terms of clinical presentation, imaging data, facial nerve outcomes, and surgical complications. The retrosigmoid approach was used in each case, and all patients had follow-up for at least 1 year. Chi-square and Fisher’s exact test were used for statistical analysis. RESULTS: The mean tumor size in Group A was 3.8 cm compared with 1.5 cm in Group B. In Group A, clinical signs of hearing dysfunction, gait ataxia, and facial paresthesia were present in 96.7%, 66.7%, 50% of patients respectively, compared with 100%, 5.6%, and 11.1% respectively in Group B. Radiographic signs of hydrocephalus were observed in 56.7% of Group A subjects, and 5.6% of those in Group B. At 1 year follow-up, 40% of patients with large VS and 94.4% of patients with small to medium size VS had good facial nerve outcomes (House-Brackmann [HB] facial grading scale grade I-III). Significant differences between the two groups were found only in gait ataxia (p<0.001), facial paresthesia (p=0.006), radiographic signs of hydrocephalus (p=0.002), facial nerve outcome 1 month (p<0.001) and facial nerve outcome 1 year (p<0.001). CONCLUSION: In patients with large size VS, microsurgical resection had poor facial nerve outcomes compared with those of their counterparts with small to medium size VS. Planned subtotal resection with postoperative radiosurgery might attain superior facial nerve outcomes and result in better quality of life in subjects with large VS.