Study of postoperative facial nerve function influenced by sterical position between facial nerve and vestibular schwannoma

Objective: To study the postoperative facial nerve function influenced by sterical position between facial nerve (FN) and vestibular schwannoma (VS).

Methods: A retrospective review was performed of 101 patients with unilateral VS, who underwent tumor total removal via enlarged translabyrinthine approach between 2003 and 2006. Data concerning tumor stage based on tumor size, intra-operative sterical position between FN and VS which was classed on 4 types (type I: FN anterior to VS; type 2: anterior and superior to VS; type 3: superior to VS and type 4: posterior to VS), postoperative facial nerve function according to the House and Brackmann classification at days 7, 30, 90 and 180.

Results: The facial nerve was preserved anatomically in 98%. The intra-operative sterical position between FN and VS was found in 43% for type 1, 33% for type 2 and 24% for type 3, but none for type 4. Good facial function at days 180 was present in 73% and decreased along with the augmentation of tumor size. Statistically, there had a significant correlation between the sterical position and postoperative FN function. Good facial function in type 1 was better than that of type 3.

Conclusions: The rate of anatomic preservation of FN does not parallel that of good postoperative facial function. The prognostic factor of latter includes not only tumor size, but also sterical position between FN and VS.