Internal Carotid Artery Injury in Endoscopic Endonasal Surgery: The Value of Intraoperative Magnetic Resonance Imaging

BACKGROUND AND IMPORTANCE: Internal carotid artery (ICA) injury is a devastating complication of endoscopic endonasal surgery. We report a case of completely resected clival chordoma using endoscopic endonasal surgery despite intraoperative ICA injury. Intraoperative MRI (iMRI) was used to localize the bleeding site, confirm resection degree and ICA patency distal to the injury site, and rule out intraoperative ischemia. CLINICAL PRESENTATION: A 16-year-old girl presented with right-sided facial paresthesia and was diagnosed with a large, invasive skull base lytic lesion centered in the clivus. The patient's neurological examination was normal, except for decreased sensation on the right side of the face. During tumor resection, massive bleeding occurred from the ICA paraclival segment, which was by applying direct pressure using hemostatic agents. Partial tumor resection, no clear signs of ischemic injury, and a patent flow distal to the ICA injury site were observed using iMRI. These findings helped in the decision to proceed with surgery and complete gross total resection. Postoperative angiography immediately performed after surgery revealed a pseudoaneurysm that was successfully embolized with coils. After discharge with no new neurological deficits, the postoperative imaging showed complete resection and no evidence of ischemic stroke in the injured ICA distribution. CONCLUSION: Although not commonly used to detect skull base lesions, iMRI was valuable in our chordoma case and enabled the surgical team to proceed with a complete surgical resection. It provided real-time evaluation of the injury and possible complications. Thus, iMRI should be considered for high-risk skull base ICA injuries.