OBJECTIVEInternal carotid artery (ICA) injuries during endoscopic endonasal surgery (EES) are catastrophic complications. Alongside the advancements in medical instrumentation and material, there is a need to modify previous treatment modalities and principles.METHODSA retrospective review of 3658 patients who underwent EES performed at the authors' institution between January 2012 and December 2017 was conducted. Ultimately, 20 patients (0.55%) with ICA injury following EES were enrolled for analysis. Data collection included demographic data, preoperative diagnosis, injury setting, repair method, and immediate and follow-up angiographic and clinical outcomes.RESULTSAmong the 20 patients, 11 received immediate endovascular therapy and 9 were treated only with packing. Of the 11 patients who received endovascular treatment, 6 were treated by covered stent and 5 by parent artery occlusion (PAO). The preservation rate of injured ICA increased from 20.0% (1 of 5) to 83.3% (5 of 6) after the Willis covered stent graft became available in January 2016. Of the 20 patients in the study, 19 recovered well and 1 patient-who had a pseudoaneurysm and was treated by PAO with a detachable balloon-suffered epistaxis after the hemostat in her nasal cavity was removed in ward, and she died later that day. The authors speculated that the detachable balloon had shifted to the distal part of ICA, although the patient could not undergo a repeat angiogram because she quickly suffered shock and could not be transferred to the catheter room. After the introduction of a hybrid operating room (OR), one patient whose first angiogram showed no ICA injury was found to have a pseudoaneurysm. He received endovascular treatment when he was brought for a repeat angiogram 5 days later in the hybrid OR after removing the hemostat in his nasal cavity. Of the 4 surviving patients treated with PAO, no external carotid artery-ICA bypass was required. The authors propose a modified endovascular treatment protocol for ICA injuries suffered during EES that exploits the advantage of the covered stent graft and the hybrid OR.CONCLUSIONSThe endovascular treatment protocol used in this study for ICA injuries during EES was helpful in the management of this rare complication. Willis stent placement improved the preservation rate of injured ICA during EES. It would be highly advantageous to manage this complication in a hybrid OR or by a mobile C-arm to get a clear intraoperative angiogram.