Resection of Mesencephalic Cavernoma Using the "Half-and-Half" Approach: 2-Dimensional Operative Video.

Brainstem cavernous malformations present a particular challenge to neurosurgeons. Their deep location and proximity to critical brainstem nuclei and fiber tracts make surgical access challenging. Despite this, microsurgical resection of brainstem cavernomas has been associated with good long-term neurological outcome, albeit with notable (but temporary) perioperative morbidity.  Here, we demonstrate the microsurgical resection of a mesencephalic cavernoma via a "half-and-half" approach. Described as the temporopolar approach by Sano in 1980,1 this approach centers on the oculomotor nerve and combines the transsylvian and pre-/subtemporal corridors. A wide opening of the Sylvian fissure and posterior mobilization of the temporal lobe permits access to the interpenducular cistern, mesencephalon and rostral pons. In this way, the "half-and-half" ideally suited for lesions of the anterior and antero-lateral brainstem. While temporary postoperative oculomotor nerve palsy is not uncommon, rapid resolution is expected.  Verbal consent was provided by the patient for reproduction and publication of her case.