Facial nerve outcomes in middle cranial fossa versus translabyrinthine approaches

Abstract

Objectives: To compare facial nerve outcomes between middle cranial fossa (MCF) and translabyrinthine (TL) approaches for resection of size-matched vestibular schwannomas. Methods: Retrospective review of vestibular schwannoma data base revealed 209 patients who underwent resection utilizing either MCF or TL approaches and had complete data. Patients in each group were matched for tumor size to eliminate the effect of this variable on facial nerve outcomes. Tumor size was determined as the longest dimension of the tumor on MRI including the intracanalicular portion. Thirty-five patients were identified in each group with matching tumor sizes. The initial, first follow-up and final facial nerve examinations were compared between the 2 matched surgical groups. Fisher’s exact test was used to compare facial nerve outcomes between the 2 surgical approaches. Results: The mean tumor size in MCF group was 1.02 cm (range, 0.6–1.7 cm) while the mean tumor size for the TL group was 1.06 cm (range, 0.4–1.5 cm). A t test confirmed the absence of significant difference in tumor size between the 2 surgical groups. Using Fisher’s Exact test, no difference was found in final facial nerve outcomes between the 2 surgical groups. The translabyrinthine approach did appear to have better early facial nerve outcomes compared to the middle fossa approach. Conclusions: There is no difference in final facial nerve outcomes between TL and MCF approaches for resection of vestibular schwannomas up to 17 mm in size. Patients in this group can be counseled that there is no increased risk of permanent facial nerve injury when using a MCF approach.