Descent of the anterior communicating artery after removal of pituitary macroadenoma using transsphenoidal surgery

BACKGROUND: After removal of pituitary macroadenoma, the anterior communicating artery (AComA) descends toward the original position. However, the process and contributing factors of this descent are not elucidated. METHODS: This retrospective study included 102 patients who underwent transsphenoidal surgery (TSS) for macroadenomas with maximum diameters of >2 cm. Sequential T2-weighted magnetic resonance images were used to assess the AComA flow void and its distance from the planum sphenoidale before and after TSS. The AComA position in relation to the adenoma was divided into four groups as follows: anterior, anterosuperior, superior, and posterior. The descent was compared to the presence of intratumoral hemorrhage or adenoma extension into the sphenoid sinus. RESULTS: One week after TSS, the AComA descent was more pronounced than when originally in the superior position (6.5 ± 3.7 mm vs 4.4 ± 3.5 mm, P < 0.0001). The postoperative descents of the AComA were well correlated with those of residual adenomas only when in the superior position (P = 0.030). The AComA descent was more significant at 1 week (4.4 ± 3.5 mm) than at 1 week to 3 months (0.7 ± 1.0 mm) in all the groups. Both intratumoral hemorrhage and sphenoid sinus extension of adenoma did not affect the AComA descent in each group. CONCLUSION: AComA descent was most influenced when it was superior to the macroadenoma and progressed mostly within 1 week after TSS, probably initiating during TSS. The position of the AComA in relation to a macroadenoma should be considered preoperatively to avoid vascular injury.