Anterior Communicating Artery Aneurysms: Surgical Strategy and Outcome based on Proposed Newer Classification

The ruptured anterior communicating artery aneurysm is the most frequent intra-cranial aneurysm treated at any neurosurgical department. These aneurysms arise from either the A1-A2-Acom artery junction or Acom artery. The surgical outcome depends on the age of the patient, time duration between ictus and surgery, and Hunt and Hess grade at admission. In this article, we intend to analyze the surgical outcome based on our proposed classification with our overall experience of Acom aneurysm.

A retrospective review of our surgical database with 250 patients of ruptured Acom was done, and the location, morphology, and direction of aneurysm, along with other clinical parameters including the demographic profile, radiological findings, and intra-operative details, were studied. We classified the Acom based on both site of origin and morphology (Type I, junctional on the dominant side; Type II, fusiform with an ill-defined neck and branching pattern; Type III, saccular true Acom A) and secondarily as described in the literature on the basis of the direction of fundus (Type A-E). The clinical parameters were compared among the above groups using Fischer-exact and one-way analysis of variance test.

A total of 250 patients (M: F =113:137) were included (mean age 52.1 ± 11.5 standard deviation years). 55.2% patients had left A1 dominance. Type I Acom A was commonly found on the left dominant circulation (P = 0.00). The difference in aspect ratio of Type I (2.0 ± 0.8) and Type II (1.8 ± 0.52) aneurysms was insignificant (P = 0.28). However, a significant difference in post-operative vasospasm among different types of aneurysms was found (P < 0.05). The Type I Acom A were anteriorly directed, while Type II and III were posteriorly directed (P = 0.001). The mean follow-up of the study was 44.4 ± 25.7 months, with age (P = 0.007) and Hunt and Hess grade (P = 0.001) at admission correlating with surgical outcome.

Classifying the Acom A pre-operatively based on site and morphology, location, and direction of fundus helps in surgical planning and prognosis. The junctional 'Type IA aneurysms' are most common and possess a high intra-operative rupture rate. The anteriorly directed aneurysms have a better prognosis, and visual complaints are usually associated with anterior-inferiorly directed aneurysms.