LAUSR

Thalamic cavernous malformations (CM) are highly surgically challenging. In this illustrative video, we present a case of a 36-year-old male with a CM located at the left medial thalamus, which was successfully treated via a contralateral anterior interhemispheric transcallosal approach. An informed consent was obtained from the patient. Preoperative imaging demonstrated that the CM appeared to have reached the pial surface superiorly and medially, and the pyramidal tracts were shown to be travelling laterally to the CM on the diffusion tensor imaging. Based on the "two-point" principle and in order to avoid pyramidal tract impingement, an anterior interhemispheric transcallosal approach was chosen. Furthermore, in order 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 auto-retraction, 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, the left ventricle was subsequently entered. After opening a thin layer of hemosiderin-stained pia on the superior surface of the left thalamus, some sand-like 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 didn't experience any intraoperative electrophysiological monitoring changing and recovered well post-operatively.