Thrombotic, Dolichoectatic, Distal Posterior Cerebral Artery Aneurysm Treated with Excision and P2-P2 Reanastomosis.

Posterior cerebral artery aneurysms are rare and often optimally treated with clip reconstruction.1-3 Complex cases may require aneurysm excision with in situ reanastomosis.4-6 A woman in her early 40s presented with 2 weeks of severe headache and received a diagnosis of a thrombotic, dolichoectatic, distal right P2 aneurysm. Clip reconstruction was recommended. After providing consent, the patient underwent a right subtemporal approach. The P2 aneurysm was encountered in the ambient cistern. The aneurysm and its inflow and outflow arteries were isolated, and bleeding was controlled with temporary clips. Primary clip reconstruction was aborted due to a neck configuration that precluded preservation of the outflow vessels during primary clip reconstruction. The decision was made to excise the aneurysm and perform a P2-P2 end-to-end reanastomosis.7 After completion of the initial bypass, indocyanine green videoangiography indicated bypass thrombosis, which was thought to be attributable to poor tissue quality from inadequate vessel trimming at the anastomosis site. We elected to excise the bypass, trim both P2 ends back to healthy tissue, and perform a repeat end-to-end P2-P2 reanastomosis, which ultimately resulted in successful revascularization with indocyanine green confirmation. Postoperative angiography confirmed complete obliteration of the aneurysm with stable graft patency, and the patient remained intact at her neurologic baseline through last follow-up at 6 weeks after discharge from the hospital. Video 1 demonstrates microsurgical nuances for deep end-to-end reanastomosis, as well as intraoperative troubleshooting in the setting of a complex ruptured posterior circulation aneurysm.

Selection of approach and bypass for fetal-type posterior cerebral artery aneurysm: illustrative cases.

BACKGROUND: Unlike in aneurysms of the adult-type posterior cerebral artery (PCA), in aneurysms of the fetal-type PCA, parent artery occlusion (PAO) results in vascular insufficiency and major ischemic strokes. Preservation or reconstruction of fetal-type PCAs is necessary to prevent these complications. Furthermore, it is necessary to select an appropriate bypass method and approach for revascularization of the PCA. OBSERVATIONS: The authors report 2 cases of aneurysms of fetal-type PCAs that were successfully treated with PAO with revascularization. A 38-year-old man with a large unruptured right PCA aneurysm at the postcommunicating (P2) segment underwent trapping with superficial temporal artery-PCA bypass via the anterior temporal and subtemporal approaches. In addition, a 45-year-old woman with a left PCA aneurysm at the quadrigeminal (P3)-cortical (P4) segments resulting in subarachnoid hemorrhage underwent proximal clipping of the P3 segment via the occipital interhemispheric approach with an occipital artery-PCA bypass. Although she had perforator infarction, major ischemic stroke was prevented, and aneurysm occlusion was accomplished in both cases. LESSONS: Aneurysms of fetal-type PCAs pose a risk of ischemia due to PAO. The combined use of bypass and revascularization should be considered to prevent major ischemic stroke after occlusion of the fetal-type PCA. However, perforator infarction is a concern.