Management and outcomes of large and giant vestibular schwannomas. Experience in 567 cases over 35 years.

Objective: (1) Study the preoperative predictive factors (such as duration of symptoms, tumor size, and cystic component) and their effects on the type of resection and facial nerve (FN) outcomes. (2) Analyze the intraoperative predictive factors, such as the extent of resection and intraoperative FN stimulation. (3) Compare our approaches (enlarged translabyrinthine approach, transotic and transcochlear approaches) to other approaches (retro sigmoid) and review the literature comparing different approaches. (4) To inquire if the surgical decision (total vs. non-total removal) and outcomes (complications and facial nerve function) of large and giant VS surgery have changed during 35 years at Gruppo Otologico.

Methods: A total of 567 cases out of 3707 were enrolled. The inclusion criteria were patients with tumors > 30 mm extrameatal diameter undergoing a translabyrinthine approach with a minimum follow-up of 12 months.

Results: The mean duration of symptoms was 35.9 months, pronounced more in the elderly (53.4 months) than in younger individuals (33.9 months). The mean tumor diameter was 36.6 mm, and 50.4% of them were cystic. Total resection (TR), near-total resection (NTR), subtotal resections (STR), and partial resection (PR) were achieved in 73.2%, 7.4%, 10.2%, and 9.1% of cases, respectively. Regrowth was observed only after STR and PR (20.7% and 44.2%, respectively). We excluded the sacrificed facial nerves (no.86) from the results of the FN outcomes. Postoperatively, FN outcomes were as follows: HB I-II 42.2%, HB III 46.9%, and HB IV-VI 10.8%. Younger individuals underwent TR in 403 (79.3%) cases, against 12 (20.3%) elderly individuals. Non-total resections (NTR/STR/PR) were performed in 47 (79.7%) cases in the elderly as against 105 (20.7%) in younger individuals. For experience effect, there were increased cases of NTR, STR, and PR (18.8% before 2004, 28.9% ≥ 2004), while the rate of complications decreased (24.8% before 2004, 13.1% ≥ 2004).

Conclusions: TR and NTR are good strategies for tumor control and FN outcomes. Preoperatively, longer symptom duration, profound deafness, and tumor diameter of ≥ 4 cm adversely influence facial nerve outcome after surgery. Conversely, cystic tumors may have a favorable influence. Additionally, intact FN responding to a stimulus after tumor resection anticipates good long-term FN (HB I-III) outcomes. With experience, operating time decreases and there may be an increase in poor outcomes of FN due to the high rate of operated giant tumors. Long-term follow-up is recommended.