C68 Steel across the cavernous sinuses, saved by Willis: a tale of transcirculatory trapping and surgical extraction

<h3>Introduction</h3> Penetrating skull base injuries involving the cavernous sinuses and internal carotid artery (ICA) are exceptionally rare and pose high risk of haemorrhage and infarction. When direct repair is unfeasible, the Circle of Willis may offer both collateral flow and endovascular access for vessel control. <h3>Case Description</h3> A young patient presented with a retained knife penetrating the right temporal bone, crossing both cavernous sinuses, and lodging in the left cavernous ICA. Imaging showed spontaneous ICA occlusion just proximal to the blade tip, with preserved perfusion via a robust posterior communicating artery (Pcom). A balloon occlusion test confirmed tolerance to left ICA sacrifice. Endovascular trapping was performed using a dual-access strategy: the proximal cavernous ICA was coiled via the left ICA, and the distal segment was occluded retrogradely through the Pcom from the basilar artery. A tailored frontotemporal craniotomy allowed careful extraction of the blade and reconstruction of the cavernous. Minor bleeding at the site was controlled with n-butyl cyanoacrylate (NBCA) injection into the pre-placed coil mass. No intraoperative haemorrhage occurred. Postoperative imaging confirmed intact perfusion and no infarction. The patient recovered with only mild, transient cranial nerve symptoms. <h3>Conclusions</h3> This case highlights the life-saving role of the Circle of Willis not just in maintaining perfusion, but in enabling transcirculatory access for endovascular vessel control. Combined with meticulous surgical extraction, this approach allowed safe management of a rare and anatomically extreme neurovascular injury. <h3>Conflict of Interest</h3> No