Zygomatic approach for lesions in the interpeduncular cistern.

Lesions in the interpeduncular cistern include basilar tip aneurysms, craniopharyngiomas, and chordomas. The surgical approach to these lesions presents a special technical problem, particularly when they are located high in the interpeduncular fossa. For the purpose of minimizing brain retraction and achieving excellent exposure within the interpeduncular cistern, the authors have developed a new surgical technique which involves detachment of the zygomatic arch. The patient is placed in the supine position with the head rotated 45 degrees to the contralateral side and tilted down 30 degrees so that the surgeon can see into the interpeduncular cistern obliquely from below. The zygomatic arch of the temporal bone as well as a portion of the lateral orbital rim (the posterior ridge of the frontal process of the zygomatic bone) is removed to expose the anterior temporal base. With posterior retraction of the temporal lobe, the arachnoid membranes covering the Sylvian stem are opened in a retrograde fashion until the tentorial edge is sufficiently exposed. The posterior communicating artery and the optic tract are elevated to enter the interpeduncular cistern, after which the oculomotor nerve is dissected free of its surrounding arachnoid membranes and displaced posteroinferiorly. Two patients with basilar tip aneurysms were operated on with this zygomatic approach, and a subtemporal modification of the zygomatic approach was used to treat a craniopharyngioma and a chordoma in two other patients. The procedure is described and a short description of its clinical use is given.