Three-dimensional morphometry of the A2 segment of the anterior cerebral artery with neurosurgical relevance

Description of the anterior cerebral artery and its cortical branches: Variation in presence, origin, and size

OBJECTIVE

Certain aspects of the anterior cerebral artery (ACA) cortical branches tend to vary, including absent or additional arteries, variation in origin, and changes to diameter and length. Knowledge of these factors can be crucial in aneurysm and arteriovenous malformation surgery. Few studies report on these aspects and a South African study have not been completed. Therefore, the aim of this study is to report absent or additional arteries, the origin, diameter and length of ACA cortical branches in a Western Cape population.

METHODS

A coloured silicone was injected into the ACA of 121 hemispheres (60 right, 61 left), consisting of 83 males and 38 females. Specimens were divided in groups younger than 34 (n=36), between 35 and 48 (n=35), older than 49 (n=40), and unknown (n=10). There were three population groups; coloured (n=72), black (n=37), white (n=10), and unknown (n=2). Any absent or additional arteries were noted, as well as the origins. External diameter and lengths were measured using a digital micrometre, string and a ruler.

RESULTS

The diameter and lengths indicated significant differences between right and left, sex, age and population groups. Most commonly absent (callosomarginal artery) and additional (paracentral lobule artery) arteries were noted. Origins were similar to the literature; however, previously unreported origins and common trunks were also observed.

CONCLUSION

The aspects reported have been neglected in previous work and neurosurgeons should be aware of these variations and anomalies to avoid complications. Studies should continue to assess the cerebral vasculature since undocumented variations are still being reported.

Detailed description of the anterior cerebral artery anomalies observed in a cadaver population

Anomalies of the anterior cerebral artery (ACA) include the median ACA (MedACA), bihemispheric ACA (BihemACA) and the azygos ACA. Knowledge of these anomalies can be crucial to clinicians and neurosurgeons, especially during surgeries involving the interhemispheric region and in the interpretation of the clinical signs of a stroke. Since few reports exist on the origin, area supplied, diameter and length of the ACA anomalies, the aim of this study is to give a detailed description on the anatomy of the ACA anomalies. The ACAs of 60 brains were injected with a colored silicone. When an anomaly was observed, a detailed illustration of the course and pattern of the ACA and cortical branches were made. The origins and the areas supplied by the anomalous arteries were noted. The external diameter was measured using a digital micrometer and the length was measured using string and a ruler. There were seven cases (11.7%) of a MedACA and 12 cases (20.0%) of a BihemACA. The MedACA originated mostly from the anterior communicating artery, and from the A2 segment in one case. The MedACA was bilateral in four cases and unilateral in three cases. Excluding Cases 5 and 9, the BihemACA cases can be divided into two groups; one branch to the left hemisphere (n=3), and one branch to the right hemisphere (n=7). The average diameter of both the BihemACA and MedACA was 1.8mm. Studies rarely provide additional information on these anomalies. Therefore, the present study elaborated on the origin, diameter, length and the area supplied by these anomalies. The definitions are described in the literature, although additional criteria were still lacking and this was provided in the present study. Since information on these aspects of the ACA anomalies is scarce, future research should give detailed descriptions on the ACA anomalies.