Short Segment Internal Maxillary Artery to Middle Cerebral Artery Bypass: A Novel Technique for Extracranial-to-Intracranial Bypass

BACKGROUND: Traditional high-flow extracranial-to-intracranial (EC-IC) bypass procedures require a cervical incision and a long (20-25 cm) radial artery or saphenous vein graft. This technical note describes a less invasive, EC-IC bypass technique using a short-segment (8-10 cm) of the radial artery to anastomose the internal maxillary artery (IMAX) to the middle cerebral artery. CLINICAL PRESENTATION: Anatomic dissections were performed on 6 cadaveric specimens to assess the location of the IMAX artery using an extradural middle fossa approach. Subsequently, the procedure was implemented in a patient with a giant fusiform internal carotid artery aneurysm. TECHNIQUE: A straight line was drawn anteriorly from the V2/V3 apex along the inferior edge of V2. The IMAX was found 8.6 mm on average anteriorly from the lateral edge of the foramen rotundum. We drilled to a depth of 4.2 mm on average to find the medial extent of the artery and then lateral and deep drilling exposed an average of 7.8 mm of graft. The IMAX was consistently found running just anterior and parallel to a line between the foramens rotundum and ovale. In the clinical case presented, both intra-operative indocyanine green and postoperative conventional angiography revealed a patent graft. The patient did well clinically without any new deficits. CONCLUSION: The advantages of this new technique include the avoidance of a long cervical incision and potentially higher patency rates secondary to shorter graft length than currently practiced.