The "SHI" Internal Maxillary Bypass for Giant Fusiform Middle Cerebral Artery Bifurcation Aneurysms: 2-Dimensional Operative Video.

Although the extracranial-to-intracranial bypass has been widely used for 5 decades, the substantive modification in this technique has rarely presented except for the internal maxillary artery (IMaxA) bypass. Recently, the IMaxA bypass has been redefined as the new "workhorse" for high-flow arterial reconstruction and replaced the cervical artery bypass as the results of sparing second incision, short graft harvesting, and well-matched caliber between donor and recipient. This video demonstrates a 37-year-old female who presented with a 1-month history of severe headache. Her complex middle cerebral artery (MCA) aneurysm was treated by IMaxA bypass with radial artery graft. Preoperative neuroimaging revealed a giant, fusiform, thrombosed aneurysm that extensively involved the sphenoidal (M1) and insular (M2) segments of the MCA. After a multidisciplinary discussion, the reversal high-flow IMaxA bypass was performed, followed by proximal MCA occlusion. We approached the aneurysm using a frontotemporal craniotomy with zygomatic osteotomy to expose the pterygoid segment of IMaxA (IM2), which is defined as the "SHI" IMaxA bypass method. Simultaneously, the radial artery graft was harvested and prepared before being anastomosed in an end-to-end fashion to the IM2 using No. 9-0 polypropylene. The free end of the RAG was then brought to the sylvian fissure and anastomosed to the M2 in an end-to-side manner. The proximal part of M1 after the bypass takeoff was then occluded with a permanent aneurysm clip (Aesculap Instruments Corp., Tuttlingen, Germany). Complete elimination of the aneurysm with a patent graft artery was observed postoperatively, and the patient was discharged with intact neurologic function (modified Rankin Scale score 0).