BACKGROUND AND IMPORTANCE: Iatrogenic internal carotid artery (ICA) injuries during endoscopic endonasal approach (EEA) surgeries are associated with a high morbidity and mortality, with few acceptable methods described for repair. CLINICAL PRESENTATION: A 13-year-old girl with a large anterior and central skull base osteoblastoma incurred an iatrogenic cavernous ICA injury during a staged EEA approach. Intraoperative angiogram was performed with balloon-assisted EEA primary microsurgical repair of the lacerated ICA. CONCLUSION: By integrating current techniques commonly used in open aneurysm surgeries and in endovascular procedures, we developed a rapid, safe technique to repair an EEA-associated iatrogenic ICA injury.