Surgical Removal of Large Petroclival Meningiomas: the Transpetrosal Approach

ABSTRACT

For surgery involving complex lesions of the petroclival region, the transpetrosal approach-which may be anterior or posterioris known to have distinct advantages over traditional approaches. Six patients with large petroclival meningiomas(over 4.5cm), underwent surgery. In three cases, where the lesion extended only into the posterior fossa, the posterior transpetrosal approach was used, and in the other three, where it extended into the Meckels cave or cavernous sinus, surgery involved a combined anterior-posterior transpetrosal approach. In three cases with serviceable hearing, the retrolabyrinthine technique was employed, the remaining three, without serviceable hearing, were subjected to the translabyrinthine technique. Total removal was achieved in three cases(50%), and no patient died. Immediate postoperative neurological dysfunction appeared in all cases; almost all involved new cranial nerve deficit. As time passed, this dysfunction became less serious, though in four cases, it was permanent; there was mild to moderate hemiparesis in two cases and facial nerve paralysis in two. The surgical outcome was good in four cases, fair in one and poor in one. The authors suggest that the selection of surgical approach to petroclival meningiomas should be based upon the size and location of the tumor, the extent of dural attachment and the status of the patient's hearing. For a high-risk group, with brain stem invasion, arterial and cranial nerve encasement and cavernous sinus invasion, subtotal resection of the tumor is recommended.