Microsurgical Resection of a Left Cerebral Peduncle Cavernous Malformation: 3-Dimensional Operative Video

Brainstem cavernous malformations are challenging lesions considering the numerous eloquent structures frequently related. Surgical resection is the preferred treatment if the patient is symptomatic and the lesion can be safely resected. We present the case of a right-handed 38-yr-old female, presenting with progressive impairment of her handwriting. Physical examination showed a right-sided grade 4/5 hemiparesis. Preoperative imaging was suggestive of a left cerebral peduncle cavernous malformation with a recent area of hemorrhage. The most superficial portion of the lesion was on the surface of the brainstem in the supratrigeminal safe entry zone of the pons. A frontotemporal craniotomy was performed, followed by a pretemporal transtentorial approach. Prior to performing brainstem incision, the area was stimulated, and no motor evoked potential was recorded. The hematoma was then evacuated, and the cavernous malformation was dissected and removed. The capsule was also dissected and removed, using neurophysiological monitoring to guide this procedure. The lesion was completely resected, and the patient was discharged on postoperative day 7 with a right-sided hemiparesis grade 3/5, which improved to grade 5/5 after 4 mo. The patient presented an improvement of her symptoms, with no new neurological deficits. Brainstem cavernomas can be safely removed in selected cases, using the adequate safe entry zone and the appropriate surgical approach. The pretemporal route can be used to reach the anterolateral aspect of the upper part of the brainstem, as it combines the advantages of both transsylvian and subtemporal approaches. An informed consent was obtained from the patient for publication of this operative video.