Surgical management of refractory ischemic-side aneurysms in chronic internal carotid artery occlusion: insights from cases unfit for endovascular treatment.

Background: Managing ipsilateral intracranial aneurysms (IAs) in chronic internal carotid artery occlusion (ICAO) is surgically challenging, particularly when endovascular treatment is not viable. This study delineates patient characteristics, individualized microsurgical strategies, and outcomes.

Methods: A retrospective review was conducted of patients with chronic ICAO and ipsilateral IAs treated between 2015 and 2023. Based on surgical stroke risk, patients were stratified into low- and high-risk groups and received individualized treatments, including aneurysm clipping, external carotid artery-radial artery-middle cerebral artery (ECA-RA-MCA) or superficial temporal artery-middle cerebral artery (STA-MCA) bypass, or combined procedures. Outcomes were assessed via angiography and the modified Rankin Scale (mRS).

Results: The cohort included 14 patients (mean age 50.56 ± 15.69 years) with 17 aneurysms. Symptoms included subarachnoid hemorrhage (SAH, n = 5) and cerebral ischemia (n = 5), among others (n = 4). ICAO was right-sided (n = 6), left-sided (n = 7), bilateral (n = 1); atherosclerosis was the main cause (n = 11). Most aneurysms were saccular (n = 12) and irregular (n = 4) morphologies (mean diameter 5.38 ± 2.75 mm), located within the ipsilateral circle of Willis. Cerebrovascular abnormalities such as stenosis, agenesis, and tortuosity were frequently observed. Atherosclerosis was the predominant etiology (n = 11). Circle of Willis compensation patterns were type I (n = 3), II (n = 5), III (n = 4), and IV (n = 2). Collateral flow grades were: grade 4 (n = 2), grade 3 (n = 4), grade 2 (n = 5), and grade 1 (n = 3). In the low-risk group (n = 10), 7 received STA-MCA bypass with clipping, 2 had bypass alone, and 1 underwent clipping only. In the high-risk group (n = 4), 3 underwent ECA-RA-MCA bypass with clipping, and 1 had bypass alone. One patient succumbed to death within 30 days postoperatively, one developed focal cerebral edema accompanied by ptosis, and one Manifested ipsilateral thalamic infarction. The 30-day stroke incidence was 7.14%, with an overall complication rate of 21.42%, CT-P/MR-P imaging demonstrates a perfusion improvement rate of 57.14%. Over a mean follow-up of 41.46 ± 26.82 months, bypass patency remained 100% (n = 10), ipsilateral stroke recurrence was 7.14%, and mRS scores improved. Clipped aneurysms (n = 11, 64.70%) resolved on imaging; untreated ones (n = 4, 23.52%) remained stable.

Conclusions: In cases of chronic ICAO concomitant with ipsilateral IAs, a stratified approach based on surgical stroke risk factors, coupled with tailored bypass procedures and aneurysm clipping, represents a safe and effective strategy with promising clinical applicability for complex cases unfit for endovascular intervention.