Angiographic and Clinical Outcomes of Various Techniques of Intracranial-to-Intracranial Bypass for Complex Cases with a Review of Pertinent Literature and Illustrated Cases

OBJECTIVE:Determine the utility of intracranial-to-intracranial bypass (IIB) surgery for complex cases and bypass options. METHODS:Eighteen IIB cases were included. Each case was classified as IIB with interposition grafts and non-interposition grafts. Clinical and angiographical status were evaluated pre- and postoperatively and at the last follow-up. Angiographic images were analyzed and schematically drawn. Postoperative angiography was used to measure the bypass patency and the presence of postoperative cerebral infarction. Recipient artery occlusion time of each bypass was measured. RESULTS:14 cases were complex intracranial aneurysms (IAs), 1 case was vertebrobasilar dolichoectasia, and 3 cases were intracranial arterial steno-occlusive disease (ICAS). 10 patients had incidental discovered IAs, and 7 patients presented with neurological deficits due to ischemia or aneurysmal mass effects. 10 cases were IIB with interposition grafts, including 4 cases of superficial temporal artery (STA) and 6 cases of radial artery graft (RAG) bypass. Eight cases were IIB with non-interposition grafts, including 3 cases of in situ bypass, 1 case of reanastomosis, and 4 cases of reimplantation. The pre- and postoperative mRS were not changed or improved, and all the bypasses were patent. There was no mortality during the mean follow-up period of 50.0 months. Mean occlusion time of recipient artery was 59.5 min. Total 8 patients had postoperative cerebral infarction but almost recovered at the discharge period. CONCLUSIONS:With the proper selection of the IIB type, IIB surgery can be a suitable treatment option for some patients with complex IAs and ICAS when extracranial-to-intracranial bypass is not feasible.