Retrograde Woven EndoBridge Deployment for a Posterior Communicating Artery Aneurysm after Failed Flow Diverter Treatment: A Case Report.

We report a case of a patient in their 60s with a recurrent posterior communicating artery (PCOM) aneurysm after flow diverter (FD) placement, in whom the antegrade approach was not suitable due to coverage of the aneurysmal neck by the prior FD. Given the dominant configuration of the PCOM and the presence of a narrow but patent P1 segment, a retrograde approach via the posterior circulation was considered feasible. After confirming clinically acceptable flow from the vertebrobasilar system, a Woven EndoBridge (WEB) device was successfully deployed into the aneurysmal sac through the P1-PCOM route, intentionally covering the PCOM origin. Postoperative angiography showed stagnation of flow within the aneurysm, and complete occlusion was confirmed on follow-up angiography at 3 months. This case highlights the potential utility of retrograde WEB deployment for recurrent PCOM aneurysms following FD placement, particularly when PCOM occlusion is acceptable and anatomical access permits.