Translamina Terminalis Approach to Laser-Assisted Resection of Thalamomesencephalic Cavernous Malformation

Cavernous malformations of the midbrain require careful consideration of the risks and benefits of intervention as well as the optimal surgical approach for these challenging lesions. Excellent results can be achieved with careful surgical planning and technique. We demonstrate a contralateral left pterional craniotomy for a translamina terminalis approach to carbon dioxide laser-assisted microsurgical resection of a thalamomesencephalic cavernoma in a 59-year-old woman with progressive debilitating diplopia secondary to partial third nerve palsy (Video 1). We performed a contralateral left modified pterional craniotomy in which we limited dissection of the temporalis muscle to approximately one third rather than extending the muscle split down to the zygoma. The cavernous malformation was resected with no complications, and the patient was discharged from the hospital on postoperative day 3. She noted immediate improvement and nearly complete resolution of symptoms over ensuing weeks. This approach offers a direct route to the lesion with minimal brain transgression, while avoiding the critical structures within the interpeduncular cistern, including the basilar artery and thalamomesencephalic perforating arteries, as well as bordering neural structures, including cerebral peduncles, oculomotor nerves, and mamillary bodies. Use of the carbon dioxide laser with its 0.55-mm tip offers a low surgical profile and allows for precise cutting, thus minimizing thermal damage to surrounding tissues. The translamina terminalis approach through a pterional craniotomy offers a safe and potentially less morbid alternative to select thalamomesencephalic lesions compared with exposure through the mesencephalic surface, which in our experience often necessitates an orbitozygomatic craniotomy.