Sylvian fissure開放における工夫

─初心者が安全に剝離を進めるために─

抄録

Splitting of the sylvian fissure is the gateway for a neurosurgical beginner in microsurgery. Techniques for splitting the sylvian fissure have varied among neurosurgeons partly due to a paucity of objective data in the literature. We focused on the point along the sylvian fissure in the apex of the pars triangularis of the frontal operculum, where the subarachnoid space is reported to be relatively large and appears appropriate for the starting point of splitting the sylvian fissure. In practice, the distance from this point to the frontal base along the superficial sylvian fissure is compared between the data of preoperative 3D-CT angiography (3DCTA) surface images and that of the operative view. In both methods, anatomical identification of the pars triangularis and adjacent structures is almost definite except for cases presenting with subarachnoid hemorrhage. There is a significant correlation between them, indicating a favorable place to start splitting the sylvian fissure is approximately 31 mm distal from the frontal base. Moreover, the bifurcation of the middle cerebral artery was situated at the approximate bisect point in the line connecting the starting point with the frontal base. We concluded that preoperative 3DCTA surface image is a feasible and reliable method to determine the starting point of splitting the sylvian fissure.
We also report the importance of epiarachnoidal dissection through a subfrontal approach combined with standard subarachnoidal splitting, especially if one wishs to safely dissect severely adhesive and interdigitated parts. In most cases, a part that is hard to split is encountered, just before the M1 segment in the sphenoidal compartment of sylvian fissure has been confirmed.
This technique makes transsylvian splitting safe and promising by increasing the visualization of adhesive brain structures.