Abstract 383: Multimodal Endovascular Management for Iatrogenic ICA Injury During Endoscopic Skull Base Surgery

Introduction Iatrogenic injury of the internal carotid artery (ICA) during endoscopic endonasal approach (EEA) skull base surgery is rare but potentially catastrophic. Despite its infrequency, such injuries carry a high risk of morbidity and mortality. Optimal management requires a thorough understanding of skull base vascular anatomy and rapid intervention strategies. Materials and Methods We present the clinical course, endovascular management, and follow‐up of an 11‐year‐old female who sustained an iatrogenic ICA injury during EEA for recurrent skull base giant cell tumor resection. Results The patient presented with progressive retro‐orbital pressure. MRI confirmed tumor recurrence, and she was referred for surgical resection after conservative treatment with denosumab proved ineffective. During EEA, brisk arterial bleeding was noted while dissecting the pituitary gland from the cavernous ICA, at the medial border of the horizontal ICA segment. Immediate surgical packing temporarily controlled the hemorrhage, and the patient was urgently taken for digital subtraction angiography (DSA). Initial DSA revealed a cavernous ICA segment traumatic pseudoaneurysm and right carotid‐cavernous fistula (CCF) with retrograde drainage into the superior ophthalmic vein. Three overlapping flow‐diverting stents were deployed with interval slowing of the fistula. A repeat DSA two days later showed persistent leakage. A transvenous approach via the external jugular vein, facial vein, and superior ophthalmic vein delivered coils and liquid embolic agents targeting the fistulous point and occluding the superior and inferior ophthalmic veins, yet extravasation persisted. A second transvenous embolization (TVE) through the internal jugular vein and inferior petrosal sinus successfully occluded the fistulous site. Persistent leakage noted on follow‐up angiography required placement of a fourth flow‐diverting stent, which ultimately achieved complete hemostasis. Six‐month follow‐up DSA demonstrated persistent full resolution of the pseudoaneurysm without residual extravasation. Unlike spontaneous or traumatic CCFs, which can occasionally be resolved with TVE alone, this iatrogenic fistula involved multiple arterial defects along the cavernous ICA, necessitating sequential TVEs combined with multiple flow‐diverting stents to achieve complete vessel remodeling and hemostasis. Conclusion Iatrogenic CCFs, particularly those involving multiple arterial defects, differ from spontaneous or acquired traumatic fistulas and often cannot be managed with TVE alone. This case highlights the importance of multimodal endovascular strategies—combining flow‐diverting stents with transvenous coiling and liquid embolic embolization—to achieve hemostasis while preserving ICA patency. Iatrogenic ICA injury during EEA is life‐threatening and requires rapid recognition, coordinated intervention, and careful procedural planning. Long‐term follow‐up is essential to ensure complete vascular remodeling, prevent delayed complications, and guide safe postoperative recovery. image