Microsurgical Treatment of Complex Distal Middle Cerebral Artery Aneurysms: 2-Dimensional Operative Video

Distal middle cerebral artery (MCA) aneurysms present a surgical challenge. Not only are they less frequent, but they are also more commonly fusiform, rendering them difficult to treat by standard endovascular or microsurgical clipping techniques.1-4 Options for microsurgical treatment include trapping with or without bypass or complex clip reconstructions alone or supplemented with bypass.3,5-8 We present 2 cases that demonstrate the complex anatomy and operative techniques and that illustrate the contrasting treatment options available. The patients consented to the procedures, and they also provided informed consent for publishing their cases. The first case is a 70- year-old woman who presented with an unruptured, fusiform aneurysm arising from the angular branch of the MCA. In this case, a superficial temporal artery to angular branch direct bypass was performed, and the aneurysm was subsequently trapped. In the second case, a 71-year- old woman presented with a ruptured distal MCA aneurysm. With temporary clipping, there was robust retrograde flow into the MCA branch distal to the aneurysm on indocyanine green video angiography and no neuromonitoring changes. Therefore, no bypass was necessary, and simple trapping of the aneurysm was performed. As shown here, indocyanine green video angiography can surrogate balloon test occlusion. Balloon test occlusion evaluates extracranial and adjacent intracranial vessels, with 1.6% complications, 0.4% permanent neurological deficit, and a 20%-22% chance of infarction, despite successful results.9-11 These cases demonstrate the contrasting treatment options available for these complex aneurysms and the thorough understanding of each patient's unique anatomy that is needed for making decisions regarding the treatment of these distal MCA aneurysms.