Brain stem cavernoma excised by subtemporal-infratemporal approach.

Brain stem cavernomas are most safely removed through the pial surface at which the cavernoma is surfacing. When a lower pontine or an upper medullary cavernoma comes to the surface of the anterior portion of the brain stem, it is difficult to reach by traditional approaches. We describe a case of mid- and lower pontine cavernoma, surfacing anteriorly, which was completely excised by the subtemporal-infratemporal approach. After making a small temporal craniotomy and a zygomatic osteotomy, the petrous carotid artery was mobilized anteriorly and the petroclival bone was drilled away to reach the anterior surface of the pons using the subtemporal-infratemporal approach. A small incision was made on the anterior surface of the pons, between the CN V and CN VI and the cavernoma was completely excised with the aid of the surgical microscope and the neuro-endoscope. Immediately after the operation, the patient had a complete abducens palsy and a mild increase of left hemiparesis, both of which resolved completely within 3 months. The patient returned to the full time work without any neurological deficit. A follow-up MRI 1 year later showed the complete excision of the cavernoma. The subtemporal-infratemporal approach is useful for anteriorly located mid to lower pontine and upper medullary cavernomas.