Microsurgical anatomy of the cisternal anterior choroidal artery with special emphasis on the preoptic and postoptic subdivisions

Abstract

Object The object of this study was to delineate the microsurgical anatomy of the cisternal segment of the anterior choroidal artery (AChA). The authors also propose a new classification of this segment on the basis of its complicated course within the carotid and crural cisterns in relation to important neurovascular structures, and the site of origin, course, and areas of supply of perforating arteries. Methods Thirty cadaveric cerebral hemispheres injected with colored latex were dissected under surgical magnification to view the cisternal segment of the AChA and its perforators. Fiber dissections using the Klingler technique were performed in two additional latex injected hemispheres to follow the penetration points, courses, and terminal areas of supply of perforating branches that arise from the cisternal segment of the AChA. Results The cisternal segment of the AChA was divided into pre- and postoptic parts that meet at the artery's genu, the most medial extension point of the cisternal segment where the artery makes an abrupt turn after passing under the optic tract. The preoptic part of the AChA extended from its origin at the inferomedial side of the internal carotid artery to the artery's genu, which is commonly located just inferomedial to the initial part of the optic tract. The postoptic part coursed within the crural cistern and extended from the genu to the inferior choroidal point. The genu of the AChA was 8 mm medial to the artery's origin and was located medial to the optic tract in 13% of the hemispheres. The postoptic part was longer than the preoptic part in all hemispheres and had more perforating arteries supplying critical deep structures (preoptic 3.4 per hemisphere vs postoptic 4.6 per hemisphere), and these results were statistically significant (p = 0.01). At the preoptic part, perforating arteries arose from the superolateral portion of the artery and coursed laterally; at the postoptic part, perforators arose from the inferomedial portion of the artery and coursed medially. Perforating arteries from both segments passed most commonly to the optic tract, followed by the anterior segment and apex of uncus in the preoptic part and the cerebral peduncle in the postoptic part. Conclusions Both parts of the cisternal segment of the AChA come into surgical view during surgeries for different pathologies in and around the perimesencephalic cisterns. However, attending to the artery's genu and defining pre- and postoptic parts during surgery may help the surgeon locate the origin and eventual course of these perforators, and even estimate the terminal areas of supply of most of the perforating arteries. The proposed classification system can prove helpful in planning any operative procedure along the crural cistern and may reduce the probability of inadvertent injury to perforating branches of the cisternal segment.

Microsurgical Treatment of 86 Anterior Choroidal Artery Aneurysms: Analysis of Factors Influencing the Prognosis

“…The beginning of the AChA is often a single trunk, and its end branch (anterior perforating artery) the posterior limb of the internal capsule lacks collateral circulation. 1,[7][8][9][10][11] When the terminal segment is occluded, infarction in the supplying territory can occur, clinically characterized by AChA syndrome (►Fig. 4).…”

Flow diversion for anterior choroidal artery (AChA) aneurysms: a multi-institutional experience

“…They are not ideally treated by FD due to retrograde flow to fill the aneurysm by extensive anastomoses distally. Instead, they may be treated by coil embolization,43 clip ligation,21 or vessel sacrifice 38…”

Choroid plexus AVM with anomalous origin of the capsulothalamic artery: A case report

“…The capsulothalamic artery is known to be the largest perforating branch of the AChoA, and usually originates from the cisternal segment of the AChoA. 4,8 Although some reports have described this artery as potentially arising from the proximal plexal segment of the AChoA, 3,5 none have referred to a capsulothalamic artery originating from the LPB.…”