Keyhole Transsylvian Resection of Infiltrative Insular Gliomas: Technique and Anatomic Results

Insular gliomas have traditionally been approached through variations of large frontotemporal craniotomies exposing much of the Sylvian fissure. Due to the importance of many structures exposed by such an approach, a less-invasive approach to these lesions is a viable alternative for resection. We present the technique and results of our keyhole transsylvian approach to remove infiltrating insular tumors.

A small linear incision and keyhole craniotomy is planned under image guidance to open a transsylvian window. Using a combination of the microscope and endoscope, we remove the insula circumferentially outward. We present our results of 20 patients with gliomas confined to the insula evaluated with volumetric imaging analysis.

There were 12 right-sided and 8 left-sided tumors. The median skin-to-skin operative time was 215 minutes. 15/20 patients were discharged from the hospital on or before post-operative day 3, with 5 of those going home the day after surgery. Greater than 90% of the tumor was removed in 18 of 20 cases, with an additional case achieving 89.5% resection. In no case was the residual tumor volume greater than 3 cc. Permanent weakness occurred in 2 patients (10%). Despite a significant number of left-sided tumors, temporary dysphasia occurred in only 1 patient (12.5%), which resolved by first follow up.

Localized insular gliomas can be effectively removed through a minimally invasive approach without increasing the risk of neurological morbidity. This minimizes manipulation of uninvolved, potentially eloquent cortices, and minimizes damage to the overlying soft tissue.