Posterior Transpetrosal Transtentorial Approach for Tumors of the Petrous and Clival Regions: Experience with 25 Consecutive Cases

ABSTRACT

Because of their proximity to adjacent vital structures, and deep and narrow operative field in the surrounding compact bony structures, tumors located in the clival or petroclival regions represent a formidable technical challenge to neurosurgeons. Between April 1990 and May 1996, 25 patients(eight males and 17 females with a mean age of 44 years), harboring clival or petroclival tumors underwent surgery in our department involving the posterior transpetrosal transtentorial approach. The median follow-up period was 24 months. A total of 28 operations were performed ; in three cases, these involved two stages, in which different approaches were used. The surgical pathology included 15 meningiomas, seven neurinomas(four acoustic and three trigeminal), and one case each of myxoid chondrosarcoma, chondroid chordoma, and paratrigeminal epidermoid. Tumor size ranged from 2 to 8cm ; 16 were larger than 4cm. According to the extent of petrous resection, three different approaches were used ; retrolabyrinthine in ten cases, translabyrinthine in four, and transcochlear in eleven. The superior petrosal sinus was always sacrificed and the tentorium completely cut. Gross total removal was accomplished in 13 cases, and subtotal removal in 12. The causes of incomplete removal included cavernous sinus invasion in four cases, severe adhesion to the brain stem in two, extremely high consistency and vascularity of the tumor in two, insufficient exposure to the tumor in two, and unexpected residual tumors seen in two cases on postoperative MRI. There was no operative mortality in this series and the most common complication was cranial nerve palsy, which occurred in 15 cases. Other complications included hemiparesis in two cases, CSF leakage in two and an epidural hematoma in one. The authors conclude that the posterior transpetrosal transtentorial approach is advantageous for resecting petroclival tumors because, by avoiding unnecessary brain retraction, it significantly reduces the risk of postoperative complications, and helps provide shorter access and wider exposure of the lesion.