Contralateral Supracerebellar-Transtentorial Approach for Posterior Mediobasal Temporal Cavernous Malformation Resection

Abstract

Cerebral cavernous malformations are abnormal clusters of thin-walled sinusoidal vascular channels without intervening brain parenchyma. The most common presenting symptom is seizure, which results from hemosiderin deposition in surrounding tissues. Early surgical resection of these malformations confers the greatest likelihood of long-term seizure freedom. This operative video demonstrates the resection of a posterior mediobasal temporal cavernous malformation through a contralateral supracerebellar-transtentorial (cSCTT) approach. The patient, a 65-year-old woman, presented with a complex partial seizure with secondary generalization. On preoperative evaluation, she was neurologically intact. The risks and benefits of treatment alternatives, including observation, were explained to her. She consented to proceed with surgery to remove the cavernous malformation. The patient was placed in the sitting position with neck flexion to flatten the angle of the tentorium. A torcular craniotomy was performed to expose the confluence of the sagittal and transverse sinuses. Gravity retraction of the cerebellum plus contralateral supracerebellar arachnoid dissection allowed generous exposure of the ambient cistern and incisura with no brain retraction or transgression. The tentorium was opened, and the cavernous malformation was then circumferentially dissected and removed en bloc. Postoperative magnetic resonance imaging findings indicated complete resection without cortical injury. The patient remained free of seizures through the 6-month follow-up. Video 1 demonstrates the cSCTT approach to lesions of the posterior mediobasal temporal lobe without the need for retraction or transcortical dissection. The cSCTT approach extends the reach of the ipsilateral, infratentorial approach laterally, which is nearly 2 cm off midline, more than is possible without cutting the tentorium.

Keywords: Cavernous malformation; Seizure; Supracerebellar-transtentorial approach; Torcular craniotomy.