Microsurgical Resection of a Middle Cerebellar Peduncle Cavernous Malformation: 3-Dimensional Operative Video.

Brainstem cavernous malformations are frequently surrounded by vital structures, which often makes surgical treatment a challenging task even to the most skilled surgeon. Accordingly, microsurgical excision is preferably offered to symptomatic patients and superficial lesions.1-3 We present the case of a 41-yr-old male presenting with progressive dizziness and diplopia. Neurological examination showed horizontal nystagmus, dysmetria, and unbalance. Preoperative magnetic resonance imaging (MRI) suggested a cavernous malformation in the right middle cerebellar peduncle. A telovelar approach was employed with the guidance of intraoperative neurophysiological monitoring. An exophytic lesion was identified in the right middle cerebellar peduncle and a clear cleavage plane was obtained allowing circumferential dissection around the capsule. The lesion was removed en bloc. Postoperative MRI confirmed a complete excision of the malformation. The patient presented an improvement in his initial symptoms, with no new neurological deficit. Cavernous malformations related with the fourth ventricle can be successfully resected through a telovelar approach in select cases, especially when exophytic, where the surgeon might take advantage of the path created by the lesion. Informed consent was obtained from the patient for the procedure and publication of this operative video. Anatomic images were a courtesy of the Rhoton Collection, American Association of Neurological Surgeons (AANS)/Neurosurgical Research and Education Foundation (NREF).