Transsylvian transinsular approach for insular glioma
In 1992 Yaşargil et al. described a safe transsylvian route to resect these tumors with an acceptable complication rate and proposed a classification based on the growth patterns of these tumors 1).
Insular glioma surgery represent a unique surgical challenge due to the complex anatomy and nearby vascular elements associated within the Sylvian fissure. For certain tumors, the transsylvian approach provides an effective technique for achieving maximal safe resection.
Transsylvian approaches shorten the surgical distance to these lesions, preserve perisylvian temporal and frontal cortex, and minimize brain transgression.
Sughrue et al., 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, they remove the insula circumferentially outward.
They present ther 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 2).
Complications
The TS approach provides a shorter operative distance and preserves the noninvolved opercular cortex but requires one to work between branches of the MCA, which carries a risk of symptomatic vasospasm and infarction 3) 4).
Additionally, especially on large volume tumors with large posterior extension where wide opening of the lateral fissure and retraction of the opercula is required, a high risk of venous infarction is taken into consideration 5)