Thalamus Cavernous Malformation Resection of via Contralateral Anterior Interhemispheric Transcallosal Approach: Two-Dimensional Operative Video.

Thalamic cavernous malformations (CM) are highly challenging surgically. In this illustrative video (Video 1), we present the case of a 36-year-old man with a CM at the left medial thalamus, which was successfully treated by a contralateral anterior interhemispheric transcallosal approach. Informed consent was obtained from the patient. Preoperative imaging demonstrated that the CM appeared to have reached the pial surface superiorly and medially, and diffusion tensor imaging showed the pyramidal tracts to be traveling laterally to the CM. Based on the "Two-point" principle and to avoid pyramidal tract impingement, an anterior interhemispheric transcallosal approach was chosen. Furthermore, to avoid excessive retraction on the ipsilateral hemisphere, we selected the contralateral trajectory over the ipsilateral trajectory. The head was positioned with the right side down; thus, the space between the right hemisphere and the falx could expand because of gravity autoretraction, which could minimize the need of retraction during the interhemispheric dissection. A small incision on the corpus callosum was performed under the guidance of neuronavigation, and the left ventricle was subsequently entered. After a thin layer of hemosiderin-stained pia was opened on the superior surface of the left thalamus, some sandlike old hemorrhagic component was removed for decompression, and the lesion was carefully dissected away from the normal parenchyma within the surrounding gliosis boundary. The CM was removed en bloc, and the deep venous anomaly was well protected. The patient did not experience any intraoperative changes shown by electrophysiologic monitoring, and he recovered well postoperatively.