Two Indices Affecting the Directions of the Sylvian Fissure Dissection in Middle Cerebral Artery Bifurcation Aneurysms

Abstract

ObjectiveThis study proposes more objective methods for deciding the appropriate direction of the sylvian fissure dissection during surgical clipping in middle cerebral artery (MCA) bifurcation aneurysms.MethodsWe reviewed data of 36 consecutive patients with MCA bifurcation aneurysms. We measured 2 indices preoperatively on 3-dimensional computed tomography angiography (3D-CTA). Analysis of the calculated data allowed us to select the appropriate direction of sylvian fissure dissection for ease of proximal control of M1. Statistically, Mann-Whitney test was used.ResultsWe classified subjects into 2 groups based on the technical level of M1 exposure during surgical clipping. When it was difficult to expose M1, subjects were assigned to Group I, and Group II were subjects in whom M1 exposure was easy. The mean difference between the distances extending from the limbus sphenoidale (LS) line to the internal carotid artery bifurcation and extending from the LS line to the MCA bifurcation was 1.00 ± 0.42 mm in group I and 4.39 ± 2.14 mm in group II. The mean M1 angle was 9.36 ± 3.73° in the group I and 34.05 ± 16.71° in the group II (M1 slope gap p < 0.05, M1 angle p < 0.05).ConclusionWe have found an objective method for preoperatively verifying ease of exposure of M1 artery during surgical clipping. Therefore, we suggest use of the preoperative M1 slope gap and M1 angle as indicators in 3D-CTA selecting the direction of sylvian fissure dissection for easy proximal control of M1.

Variable Anatomy of the Middle Cerebral Artery from Its Origin to the Edge of the Sylvian Fissure: A Direct Fresh Brain Study

“…is length is measured preoperatively to determine the optimal surgical approach for dissecting and clipping MCA bifurcation aneurysms, for which 2 surgical techniques are used, i.e., opening of the Sylvian fissure from proximal to distal (for a short MT) or from distal to proximal (for a long MT). e average length of the MT of the MCA is therefore of great interest to neurosurgeons [25].…”

Microsurgical Management of the Middle Cerebral Artery Bifurcation Aneurysms: An Anatomic Feasibility Study

“…They positioned the head based on the visualization of the proximal MCA for complex type [2]. According to Park et al [4] the head should be positioned 30° toward the contralateral side and if needed, can be extended 20° for routine MCA aneurysms [4].…”

“…Middle cerebral artery (MCA) aneurysms account for 20% of all intracranial aneurysms and occur at the level of the bifurcation of the vessel in approximately 80% of cases [1][2][3][4][5]. The anatomical variations of the Sylvian fissure (SF), MCA as well as the dome of the aneurysm make the surgery of interest more challenging.…”