MATERIAL and METHODS: Surgical outcome of 36 patients with large cystic VS was retrospectively assessed, and compared with a group of 67 patients with large solid VS.

RESULTS: The anatomical integrity of the facial nerve was preserved in 88.9% of cystic group patients and in 92.5% of solid group patients. At 1 year after surgery, 75.8% of the patients with cystic VSs had favorable facial nerve function and 24.2% had poor function. There was no significant difference in facial nerve outcomes between cystic and solid tumors. When the cyst wall was closely adherent to the facial nerve, near total or subtotal resection was associated with a better facial nerve outcome compared to total excision (P<0.05).

CONCLUSION: In most cystic VS patients, favorable facial nerve function can be attained by surgical treatment via retrosigmoid approach. Special care should be taken to remove entire cystic VSs as well as partial cystic VSs with anterior or medial located cysts. When a dissection plane cannot be developed between the cyst wall and the facial nerve, near total or subtotal resection is of benefit for facial nerve function. Keywords : Vestibular schwannoma, Cystic, Retrosigmoid approach, Facial nerve outcomes