De Novo Multiple Aneurysms After STA-PCA Bypass for Ruptured Traumatic Dissecting Aneurysm of the Fetal Posterior Cerebral Artery: A Case Report

<title>Abstract</title> <p>Traumatic dissecting aneurysms of the posterior cerebral artery (PCA) are rare, and their management is particularly challenging when associated with a fetal-type PCA. We report a case of a ruptured traumatic dissecting aneurysm of the right fetal PCA, treated with a one-stage superficial temporal artery–PCA (STA-PCA) bypass and proximal coil occlusion of the right PCA. On postoperative day 9, the patient developed sudden ventricular cast hemorrhage. Emergency cerebral angiography revealed a de novo aneurysm of the right anterior choroidal artery and diffuse aneurysmal changes in the basilar artery. Despite external ventricular drainage and supportive therapy, the patient’s outcome was poor. From the perspective of the “trauma–inflammatory storm–vascular injury” cascade, we discuss the potential pathomechanism by which post-traumatic inflammatory responses may drive multiple, diffuse cerebrovascular lesions. This case underscores that severe head trauma and subarachnoid hemorrhage can trigger vascular inflammation, leading to the acute formation and rupture of remote aneurysms, and highlights the need for heightened clinical suspicion and comprehensive vascular surveillance.</p>