gms | German Medical Science

The rhomboid fossa approach is a commonly used route to the ponto-mesencephalic region of the brainstem. There are only a few reports pointing out the indications and advantages of the subtemporal approach for the treatment of ponto-mesencephalic cavernomas. We report on the indication, technique and clinical experience with the subtemporal approach as an important surgical route in selected patients harboring anterolateral brainstem lesions.

Fourteen patients with cavernous malformations in the anterolateral ponto-mesencephalic region out of a group of 68 surgically treated brainstem cavernomas were approached subtemporally by placing a lumbar drain prior to surgery. All patients were electrophysiologically monitored during surgery. A tentorial incision to enlarge the exposure was performed in all patients. The access route was evaluated on MRI-scans and by transferring data to a neuronavigation workstation. All patients underwent either postoperative MRI or CT scan. The clinical data, patients outcome and the video-documented surgical technique of the subtemporal approach were analyzed.

All patients underwent successful total resection of their cavernoma. There was no severe additional morbidity and mortality due to the subtemporal approach. The vein of Labbé was preserved in all patients. No damage of the neuronal structures in terms of temporal hemorrhage, edema, cranial nerve trauma or temporal lobe contusion was observed postoperatively.

The decision for a subtemporal approach by a limited basal temporal craniotomy needs to be based on anatomical considerations to allow successful treatment of anterolateral ponto-mesencephalic cavernomas with lowest rate of morbidity. The temporal veins do not conflict the approach and are rarely cumbersome when assessing the ponto-mesencephalic region.