Transsylvian approach to intrinsic brain tumors

The Sylvian fissure is the most prominent anatomic structure on the lateral surface of the human brain. In its floor lies the pyramidal-shaped insula, a common location for intrinsic brain tumors. Opening the Sylvian fissure via the transsylvian approach provides access to lesions not visible on the surface of the brain without dissecting through the brain. Here we describe the transsylvian approach to intrinsic brain tumors, particularly diffuse gliomas, emphasizing intrinsic tumors of the insula, which are among the most difficult tumors to resect owing to the complex neural and vascular structures within and surrounding the Sylvian fissure. We discuss relevant anatomical and surgical techniques for resecting insular tumors via the transsylvian approach, including complication avoidance. We prefer this approach to the transcortical approach because it avoids resecting healthy brain, permits early identification of critical middle cerebral artery branches (sometimes engulfed by tumor), permits identification of lenticulostriate perforators, permits early devascularization of the tumor, and exploits the normal sulcal anatomy of the operculo-insular component of the Sylvian fissure to delineate the limits of the tumor.