Dissecting aneurysms of the distal segment of the posterior inferior cerebellar arteries: clinical presentation and management

Abstract

Background and purpose: Dissecting aneurysms of the distal segment of the PICA are rare. The purpose of this study was to evaluate the clinical presentations, imaging features, treatment options, and clinical outcomes of dissecting PICA aneurysms.

Materials and methods: Six patients with dissecting aneurysms in the distal segments of PICA were found in the database of a single medical center, from November 1996 to December 2008, and retrospectively evaluated. Treatment mode and follow-up clinical outcomes were analyzed.

Results: Five patients with dissecting PICA aneurysms presented with acute intracranial hemorrhage and 1 patient presented with a large mass from an intramural hematoma. All 5 patients with intracranial hemorrhage were treated with endovascular occlusion of both the dissecting PICA aneurysm and the distal parent artery. The patient with the intramural hematoma underwent surgical trapping with end-to-end anastomosis. In 1 patient, the dissecting aneurysm recurred twice within a 5 year 3 month period, despite endovascular occlusion of both the aneurysm and the parent artery. The clinical outcome postprocedure was excellent in all patients, without permanent neurologic complication.

Conclusions: For the endovascular treatment of dissecting aneurysms in the distal PICA segments, we recommend occlusion of both the dissecting aneurysm and the parent artery to avoid leaving the point of initial intimal tear untreated. All of our patients had excellent clinical outcomes; however, our experience with recanalization illustrates the need for close follow-up of patients.

Fig 1.

A 28-year-old man (patient 4) had serious head trauma from motor vehicle crash. A, The cerebral angiogram following the second SAH shows a small aneurysm at the anterior medullary segment of left PICA. B, Selective angiogram of the left vertebral artery at the time of treatment illustrates the PICA aneurysm increased in size in a day and diffuse spasm of the vertebral and basilar artery. C, Postembolization injection of the left vertebral artery demonstrates complete occlusion of the PICA at its origin with coils in the patent artery and the aneurysm.

Fig 2.

An 80-year-old woman (patient 6) presented with sudden severe headache. A and B, Initial digital subtraction angiogram of the left vertebral artery in the frontal projection and 3D rotational angiogram show a fusiform irregular-shaped aneurysm at the anterior medullary segment with focal irregularity of left PICA, indicating dissection. C, The postembolization angiogram illustrates the dissecting aneurysm and parent artery are occluded.

Fig 3.

A 35-year-old woman (patient 5) presented with Hunt and Hess grade III SAH. A, A lateral projection of the right vertebral angiogram demonstrates a 3 × 4 mm fusiform aneurysm at the lateral medullary segment of right PICA. B, The aneurysm is treated by endovascular occlusion of dissecting aneurysm and parent artery. The postocclusion angiogram in the lateral projection shows complete obliteration of the PICA trunk and the aneurysm. C, Five-year follow-up DS angiogram; note that the occluded PICA is recanalized without any growth of the aneurysm.