Cerebral hypoperfusion necessitating additional bypass following hunterian ligation of the internal carotid artery despite reassuring intraoperative challenges: Video case report

Hunterian ligation has been adapted for complex intracranial aneurysm repair when other, more modern techniques are insufficient. Before drastic alteration of cerebral blood flow dynamics, intraoperative challenges and consideration of blood flow dynamics must be completed to ensure adequate perfusion postligation. On satisfaction, ligation may proceed; however, subtle changes related to hypoperfusion may not be immediately observed during intraoperative challenge under general anesthesia and/or before onset of the vasospasm window. In this report, we describe a patient who presented with a Hunt-Hess Grade III subarachnoid hemorrhage (SAH), with a right internal carotid artery (ICA) occlusion and a ruptured giant left ICA aneurysm. Endovascular treatment of the aneurysm was aborted because the nominal, 9 mm diameter of the ICA was too large for any intracranial balloon or stent. Three days later, she underwent a left-sided "insurance" extracranial-tointracranial arterial bypass (EIAB) using the superficial temporal artery simultaneously with hunterian ligation of the left ICA following reassuring results on intraoperative occlusion challenge. Over several days, her neurologic condition declined concurrent with the vasospasm window, and a right-sided EIAB was required to augment vascular supply. Following a protracted hospital course, the patient became progressively more independent and is currently residing in an assisted living facility. We illustrate an ultimately successful microsurgical treatment option in the setting of acute SAH that highlights the importance of cerebrovascular reserve and blood flow replacement in the setting of a compromised circle of Willis, especially during the vasospasm window.