Acute traumatic posteroinferior cerebellar artery aneurysms: Report of three cases

OBJECTIVE AND IMPORTANCE: Posterior fossa subarachnoid hemorrhage secondary to blunt head trauma is rarely associated with traumatic aneurysms of the posterior circulation. CLINICAL PRESENTATION: We present three cases of posterior fossa subarachno id hemorrhage from ruptured posteroinferior cerebellar artery (PICA) aneury sms after blunt head trauma. In each case, there was no associated penetrat ing injury or cranial fracture. All three patients presented with acute hyd rocephalus requiring ventriculostomy. Two of the three patients had a proxi mal PICA aneurysm visible on emergent angiography. The remaining patient's aneurysm, although not visible on his initial angiogram, was detected on a subsequent angiogram 72 hours later. INTERVENTION: All patients underwent successful surgical clipping of their aneurysms. Two cases required sacrificing of the parent vessels because of the friable nature of the false aneurysms. In each case, severe symptomatic vasospasm occurred, requiring angioplasty. All three patients also require d a ventriculoperitoneal shunt for persistent hydrocephalus. CONCLUSION: Features of these three cases and similar cases reported in the literature support the theory that vascular ruptures and traumatic aneurys ms of the proximal PICA may be related to anatomic variability of the PICA as it transverses the brainstem. This variability predisposes individuals t o vascular lesions, which occur in a continuum based on the severity of the injury. Posterior fossa subarachnoid hemorrhage after head injury requires a high index of suspicion and warrants aggressive diagnostic and therapeut ic interventions.