Incidence of cerebrospinal fluid leak after microsurgical removal of vestibular schwannomas.

OBJECTIVES: Cerebrospinal fluid (CSF) leak still remains an unresolved problem after microsurgical removal of vestibular schwannomas (VS).
METHODS: 14 (6%) Cases of cerebrospinal fluid rhinorrhea and 3 cases with subcutaneous retro-auricular CSF collection, occurring in a series of 224 patients operated on by the senior author (JMG) on VS between 1989-2000 via the suboccipital retrosigmoidal approach were studied retrospectively. Prophylaxis of CSF leak was usually attempted by packing the unroofed posterior wall of internal acoustic meatus with muscle. The mastoid air cells were packed first with collagen then with muscle and bone dust.
RESULTS: All CSF leaks were diagnosed within 2-7 days after surgery. We found no relation to tumour size. Treatment was initiated in all patients with continuous external lumbar cerebrospinal fluid drainage (CELCFD) for 7 days. In 11 cases with CSF rhinorrhea and all cases with retro-auricular CSF collection, the CSF leak was stopped. However, in 3 cases the CSF leak persisted despite the lumbar drain. These patients were operated on again with sealing the IAM and the mastoid cells again with muscle and collagen. No recurrence of CSF leak was noted after the second operation. There was no case of late onset CSF leak during the follow-up of one year.
CONCLUSION: Although CSF leak is a common complication (6%) after vestibular schwannoma removal, aggressive treatment is required only in a few cases (1%). Most of the cases are successfully treated by (CELCFD). The suboccipital approach offers an advantage of opening only a part of mastoid air cells, which are in our opinion the second most common site of CSF leakage.