LATERAL APPROACHES TO THE MEDIAN SKULL BASE THROUGH THE PETROUS BONE - THE SYSTEM OF THE MODIFIED TRANSCOCHLEAR APPROACH

Twenty-three patients with intradural lesions of the petroclival regio n and prepontine cistern were managed in our centres by the modified t ranscochlear approach. Total tumour removal was accomplished in 17 pat ients, while a second stage was planned for the remaining six patients . Two cases died in the immediate postoperative period. All the remain ing cases showed a good outcome and returned to work. The basic approa ch type A is further classified according to its anterior, superior an d inferior extension into types B, C and D respectively. The surgical procedure, classification, illustrative case reports and patients' sum maries are presented.