gms | German Medical Science

Objective: The formation of a traumatic intracranial aneurysm is rare, accounting for less than 1% of cerebral aneurysms. The pericallosal artery as part of the anterior cerebral circulation seems to be a locus typicus for this entity of vascular lesion. This report illustrates the importance of early diagnosis as well as of repeated investigation if the initial imaging is negative. Timing and choice of treatment of this secondary formation after vascular injury due to high-energy head trauma are critical.

Methods: Here we report on a 16-year-old patient who was involved in a moped traffic accident and admitted to the emergency room of our center of tertiary care. CT scanning revealed a mostly parenchymal corpus callosum hemorrhage as the leading lesion. The initial treatment consisted of implantation of an external ventricle drainage and a pressure probe. An aneurysm as source of hemorrhage was ruled out by angiography showing only small artery wall irregularities of the pericallosal artery. The patient was monitored on the pediatric intensive care unit. As intracranial pressure rose, bilateral decompressive craniectomy was performed.

Results: Prompted by the initial suspicion of a vascular lesion as possible source of bleeding, a follow-up control by MR-angiography was carried out on the 28^th day post trauma and revealed the formation of a pseudoaneurysm of the pericallosal artery which was affirmed by conventional 3D-angiography. This lesion was not to be seen as such in the initial angiogram but corresponded to the site which had demonstrated an irregularity of the artery-wall. This pseudoaneurysm, which had formed itself after dissection of the pericallosal artery, was then clipped by positioning of two micro-clips. Post operative neuroimaging controls demonstrated a good occlusion of the aneurysm.

Conclusions: Especially when the suspicion of a vascular lesion is raised by location or distribution of cerebral hemorrhage in spite of an undoubted, primarily traumatic etiology of intracranial hemorrhage, repeated vascular neuroimaging is critical to identify secondary vascular lesions such as traumatic pseudoaneurysm. Irregularity of artery wall morphology on initial angiography might be an early sign of the impending formation of a pseudoaneurysm. These aneurysms have a high incidence of bleeding, and clipping or coiling is urgent to prevent the disastrous consequences of a rupture.