Contralateral Interhemispheric Transfalcine Approach for Intra-Axial Medial Occipital Lesion: 2-Dimensional Operative Video.

Safe access to intra-axial mesial cortical lesions is challenging. When approached through standard transcortical approaches, normal white matter tracts such as the superior longitudinal fasciculus, corona radiata, and optic radiations may be violated en route to the lesion. Conversely, use of ipsilateral interhemispheric approaches necessitates retraction and manipulation of edematous and friable perilesional tissue. The contralateral interhemispheric transfalcine (CIHTF) approach may circumvent these challenges. The CIHTF approach uses a gravity-created window between the ipsilateral hemisphere and the falx and allows direct access contralaterally by opening the falx. We demonstrate the CIHTF approach for an intra-axial, medial occipital/precuneus lesion in a 69-yr-old man presenting with left homonymous hemianopia. MRI revealed a heterogeneously enhancing intra-axial lesion in the right mesial occipital lobe. After the patient gave voluntary informed consent, a CIHTF approach was planned, with the patient positioned laterally, right side up (IRB approval was unnecessary). A lumber drain facilitated gravity autoretraction of the ipsilateral lobe. Within the created trajectory, the falx was opened with use of a nerve hook attached to monopolar electrocautery. The contralateral lesion was visualized and removed piecemeal with the assistance of fluorescence imaging. Postoperative MRI showed complete removal. The patient reported a significant vision improvement. The diagnosis was metastatic adenocarcinoma from the lung; subsequent radiosurgery was recommended. MRI at the 8-mo follow-up revealed no recurrence of the lesion. The CIHTF approach is feasible for a mesial intra-axial lesion because it offers gravity autoretraction, a large working angle, and avoidance of parenchymal swelling. Used with permission from Barrow Neurological Institute.