Introduction The treatment of internal carotid artery termination and A1/A2 junction aneurysms can be challenging, particularly in the context of anatomical variation.

Aim of Study The study aimed to assess the safety and clinical outcomes of the use of flow diversion in the treatment of aneurysms where the A1 or A2 segment was jailed.

Methods Patients who underwent flow diversion as the primary modality of treatment between 2013 and 2022 at a single centre were retrospectively reviewed. Data was collected on patient demographics, aneurysm characteristics, intra-procedural imaging, clinical outcome, and follow-up.

Results 20 patients (80% female) with 26 aneurysms were treated where the A1 or A2 segment was jailed. The mean age was 53. Two cases were acute procedures for subarachnoid haemorrhage. Aneurysm location included the ICA (n=12), MCA (n=5), AComA (n=4), and PComA (n=5). The A1 segment was jailed on 18 occasions, and the A2 segment on two occasions. Thromboembolic complications resulting in permanent neurological deficit occurred in one patient. Other complications included groin haematomas (n=2) and hyperperfusion syndrome (n=1), all of which were successfully medically managed. 96% received follow-up, with a mean duration of 33 months. 77% of aneurysms were completely occluded (RROC 1) on most recent imaging with 92% demonstrating satisfactory occlusion (RROC 1 or 2). No patient required re-intervention.

Conclusion Jailing of the A1 or A2 segment during flow diverting treatment of aneurysms may be performed in selected cases dependent on the patient anatomy with a relatively safe and efficacious outcomes.

Disclosure of Interest no.