The paramedian supracerebellar transtentorial approach to the mediobasal temporal region

Abstract

The mediobasal temporal region (MTR) is located near the brain stem and surrounded by the eloquent neurovascular structures. The supracerebellar transtentorial approach (STA) is safe access to the posterior MTR structures, however its use for resection of anterior MTR lesions still remains controversial. The article describes the technique and outcome of surgery for different MTR structures using STA. The paramedian STA was used in 18 patients (13 females and 5 males) for 7 years. Ten patients presented with glial MTR tumors, 3 patients with cavernomas, 2 patients with arteriovenous malformations (AVMs), 2 patients with intraventricular meningiomas, and 1 patient with mesial temporal sclerosis. The patient age ranged from 19 to 57 years. In 10 cases, lesions were localized on the left. Epilepsy was the leading symptom in 14 cases. Patients underwent preoperative high-resolution MRI, electroencephalography video monitoring before and after surgery, intraoperative corticography (if necessary), and postoperative CT and MRI. Lesions were located in the anterior third of MTR in 5 patients, in the anterior and middle thirds in 2 patients, in the middle third in 5 patients, in the middle and posterior thirds in 2 patients, in the posterior third in 1 patient, in the anterior, middle, and posterior thirds in 1 patient, and in the ventricular triangle area in 2 patients. In all patients with intraventricular tumors, AVMs, and cavernous malformations and in 8 patients with glial MTR tumors, the lesions were totally resected. Two patients with intracerebral tumors underwent subtotal resection. A patient with intractable epilepsy and mesial temporal sclerosis underwent resection of the anterior two-thirds of the hippocampus and parahippocampal gyrus and, partially, amygdala using intraoperative corticography. There was no surgical mortality; 2 patients developed a transient neurological deficit, and 1 patient had a cerebellar hematoma that was successfully removed during surgery. STA enables resection of lesions localized in all parts of the MTR, without damage to the surrounding nerve and vascular structures.