Ruptured Posterior Cerebral Artery Dissecting Aneurysm After Trauma: A Case Report and Literature Review.

Posterior cerebral artery (PCA) aneurysms are rare, accounting for less than 2% of intracranial aneurysms. Among them, dissecting aneurysms frequently occur in the P2 segment. Traumatic PCA aneurysms are extremely uncommon and usually reported in pediatric or young adults following high-energy injuries. We report the case of a 43-year-old woman who sustained a ruptured left PCA P2 dissecting aneurysm with subarachnoid hemorrhage, accompanied by an L2 unstable burst fracture after a high-speed motor vehicle collision. Initial neuroimaging revealed diffuse basal cistern hemorrhage with more predominance at the left side ambient cistern and a fusiform aneurysm with a superimposed saccular component along its anterior portion of left PCA P2 segment. The patient underwent endovascular treatment with a flow-diverting stent and stent-assisted coiling, achieving complete obliteration, followed by lumbar minimally invasive spinal surgery (MISS). The patient recovered without neurological deficits and remained fully independence at a one-year follow-up. Traumatic PCA dissecting aneurysms pose a diagnostic challenge due to their rarity and potential for delayed clinical manifestation, yet they carry a substantial risk of morbidity and rebleeding if untreated. Early recognition through detailed vascular imaging and timely reconstructive endovascular intervention are essential to preventing secondary hemorrhage and optimizing clinical outcomes. This case underscores the need for heightened suspicion for vascular injury in patients with significant craniovertebral trauma.