The system of modified transcochlear approaches for intradural skull base lesions

The modified transcochlear approach was used to manage 27 patients with intradural tumours of petroclival region and prepontine cistern. Total tumour removal was possible in 21 cases. Planned subtotal removal was done in 2 elderly patients; one was a chordoma with involvement of the cavernous sinus and extending upto the optic chiasma while the other was a petroclival meningioma involving the cavernous sinus with normal abducent nerve function. The remaining 4 cases are awaiting their second stage. The modified transcochlear approach is systematized and further classified into types A, B, C and D depending upon its extensions. The basic surgical technique with its extensions, details of the classification, indications of each type and results are presented in this report.