Objective To describe the incidence and clinical course of patients who develop delayed facial nerve paralysis (DFNP) after surgical resection of vestibular schwannoma.
Setting Tertiary skull base center.
Methods Retrospective chart review.
Results A total of 246 consecutive patients who underwent surgical resection for vestibular schwannoma at a single center between 2010 and 2015 were analyzed. Of these patients, 22 (8.9%) developed DFNP, defined here as deterioration of function by at least 2 House-Brackmann (HB) grades within 30 days in patients with immediate postoperative HB ≤ 3. The mean age of DFNP patients was 47.2 years (range: 17–67) and 16 (73%) were female. The mean tumor size in greatest dimension was 2.1 cm (range: 0.7–3.5 cm). Tumors were excised via translabyrinthine (86%) or retrosigmoid (14%) approaches. At the conclusion of each case, the facial nerve stimulated at the brainstem at 0.05 mA. All patients had normal preoperative facial nerve function with the exception of one patient who was HB Grade II/VI. The mean immediate postoperative facial nerve function was HB 1.8 (range: 1–3). Average facial nerve function at the 3-week postoperative visit was 4.4 (range: 2–6). At 1 year, 8 patients (36%) recovered HB 1 function, 10 patients (46%) recovered to HB 2, and two patients (9%) were HB 3. The remaining two patients did not recover function and were HB 6 at last follow-up. Initial postoperative facial nerve function (HB 1 or HB 2) was associated with improved recovery to normal (HB 1) function (p = 0.018) (Fig. 1). No patient with initial postoperative HB 3 that had DFNP recovered to HB 1. Six patients (27%) developed synkinesis.
Conclusion The incidence of DFNP paralysis is low. A majority of patients who develop delayed paralysis will recover excellent facial nerve function. Patients with HB 1 or HB 2 function preoperatively have higher rates of complete recovery. Patients should be counseled, however, that a small percentage of patients will not recover function long-term, despite having a previously functioning and anatomically intact nerve.
Fig. 1
