Target Embolization of Dilated Post-PICA Segment for Ruptured PICA-Involved Type Vertebral Artery Dissecting Aneurysm

OBJECTIVE: In parent artery occlusion (PAO) for ruptured vertebral artery dissecting aneurysms (RVADA), target embolization using coils in a short segment to occlude only the vasodilated area containing the rupture point is selected as a first-choice procedure at our institute. We focused on RVADA involving the posterior inferior cerebellar artery (PICA) and evaluated the treatment results. METHODS: This study consisted of eight cases with RVADA involving the PICA which were treated between October 2007 and January 2020. Based on radiological findings such as the bleb, the rupture points were located at the affected vertebral artery (VA) distal to PICA in all cases. Target embolization, by which only coiling at the dilated segment distal to the VA was performed. We aimed to preserve blood flow to the PICA. The incidence and extent of medullary infarctions, and neurological outcome were retrospectively assessed. RESULTS: Regarding the diameter of bilateral VA, there were no differences in six cases while the affected VA with RVADA were larger in the remaining two cases. PICA was preserved in all cases but one in which occlusion of complementary PICA was observed. Postoperative medullary infarction was not noted. There was no rebleeding during the follow-up period. However, recanalization of the VA was observed in four cases and additional coil embolization was performed. All patients were discharged with a good outcome (modified Rankin Scale [mRS] 0; seven patients, mRS 2; one patient). CONCLUSION: Target embolization preserving the PICA in PICA-involved type RVADA was considered to be an effective treatment method for cases whose rupture point was located in the VA distal to PICA orifice.