Distance from the midline to the aneurysm as simple predictor of ischemic complication with small unruptured middle cerebral artery aneurysm surgery.

Background: This study aimed to clarify the risk factors for postoperative cerebral infarction in surgical clipping for prevalent small middle cerebral artery aneurysms (MCA Ans).

Methods: This retrospective study included 246 patients (mean age, 64.8 ± 10.0 years; 25.6 % males, 74.4 % females) with 258 aneurysms (mean aneurysm size, 5.4 ± 2.4 mm) who underwent direct surgery for unruptured MCA Ans at our institution from January 2015 to December 2020. All surgeries were performed under general anesthesia, incorporating indocyanine green videoangiography and transcranial motor-evoked potentials to enhance surgical precision and safety. The occurrence of surgery-related cerebral infarction was evaluated using postoperative CT scans within one week, comparing them with preoperative images. Patients were categorized based on the presence or absence of postoperative stroke and were analyzed for age, sex, past medical history, aneurysm size, number of clips used, and distance from the midline to the aneurysm.

Results: Seventeen patients had postoperative cerebral infarction (6.6 %, symptomatic 6, asymptomatic 11). There were no significant differences in terms of age, number of clips, or aneurysm size between the two groups; however, the distance from the midline to the aneurysm was significantly shorter in the stroke group (27.1 ± 4.7 mm; p < 0.001), with a cutoff value of 29 mm using the receiver operating characteristic curve.

Conclusion: Surgical clipping for MCA Ans presents a high risk of cerebral infarction for aneurysms located closer to the midline, emphasizing the importance of considering aneurysm location as a risk indication in surgical clipping.