Basal lateral subtemporal approach for trigeminal neurinomas: report of an experience with 18 cases

Subtemporal craniotomy centred on the external ear canal was used to surgically treat 18 trigeminal neurinomas. The approach was found to be suitable to deal with either or both the middle fossa and the posterior cranial fossa components of the tumour. The basal extension of the exposure was achieved by resection of the roots of the zygomatic arch, roof of the external ear canal and superior third of the mastoid bone. The temporalis muscle was rotated anteriorly. The direction of the approach to the tumour was the shortest and perpendicular from the surface and avoided any neural or vascular exposure or manipulation. The basal exposure was horizontally wide and significantly low which reduced the operating distance, limited the extent of temporal lobe retraction and provided additional space for manipulation of instruments. The exposure was manoeuvreable with anterior, posterior and medial expansion being possible during or prior to tumour resection. The approach had the advantage of being simple and relatively quick and of its familiarity to general neurosurgeons. The experience with the approach with trigeminal neurinomas and its possible advantages over other available approaches to these lesions are analysed in this report.