Epidermal Cysts of the Posterior Fossa and Petroclival Region—Our Own Experience

Introduction: Surgical management of epidermoid cysts is still a big challenge. One of the most important goals is radicality of operation without causing additional neurological deficits, especially cranial nerve palsies. The tumor grows slowly and usually penetrates to every accessible space around its origin, even through the foramen of Luschka into the fourth ventricle. In advanced stages of tumor growth, compression and displacement of the brainstem can be significant.

Material and Methods: Since 1988, among 224 operations of cerebellopontine angle tumors and 13 operations of petroclival region via petrosal approach, there were 23 epidermal cysts. Tumor size was defined as large diameter and ranged from 40 to 70 mm (median = 50 mm). In our paper we analyze the radicality of the operation, facial nerve status, and other details of the neurological state with special attention to cerebellar signs, hearing, and other cranial nerve status.

Results: There were no perioperative deaths. Fourteen tumors (61%) were removed totally. Five patients required reoperation, one of them three times. Facial nerve paresis before surgery was present in 9 cases (39%). Facial nerve function in long-term observation was in House-Brackmann grade I or II (good) in 52% (n = 12). In 22%, it was in grade III or IV (acceptable) (n =5), and in 17% (n = 4), observation was in grade V or VI. Since introduction of intraoperative monitoring in 1998, facial nerve has been classified as H-B grade I or II in 64% (n = 9), III or IV in 14% (n = 2), and in grade V in 7% (n = 1); no patient had facial nerve in grade VI. There was one serious complication due to air embolism, which resulted in coma and a prolonged vegetative state. This patient died 9 months later. In 4 cases, postoperative chemical meningitis occurred.

Conclusions: In our opinion it is necessary to perform a total resection, because in a relatively short time after a nonradical removal, reoperation was required. Introduction of intraoperative monitoring had a positive influence on the radicality of operation and facial nerve function in long-term observation.