Introduction: The surgical treatment of unruptured fusiform aneurysms of the vertebrobasilar system is challenging with a high morbidity and mortality rate. However, the natural history of these lesions is not well-characterized.
Methods: Three tertiary cerebrovascular referral centers retrospectively reviewed the records of patients with unruptured fusiform aneurysms of the intracranial vertebrobasilar system. Aneurysms of the basilar bifurcation and saccular aneurysms were excluded. Patient presentation, angiographic and MRI characteristics, clinical course and outcome at either most recent medical follow-up or after surgical treatment (if performed) were recorded.
Results: 52 aneurysms were identified, with mean follow-up duration of 29.1 months (range, 3 days – 12.75 years). Presentation was unsteady gait (31%), cranial neuropathy (23%), headache (27%) or lateralizing signs (10%); 12% were incidentally discovered. The average diameter was 16.1 mm (range, 4 – 39 mm). 50% contained intraluminal thrombus, 42% were associated with brainstem edema and 25% with brainstem stroke. Two aneurysms ruptured within 7 days of presentation; no other aneurysm ruptured during the follow-up period. Symptom progression was seen in 50% and was not related to aneurysm diameter, brainstem edema or antiplatelet treatment. Nineteen patients (37%) were surgically treated due to either symptomatic or radiological progression. Good outcome (mRS 0-2) was seen in 63% in both surgical and medical groups.
Conclusions: Unruptured fusiform vertebrobasilar aneurysms are often associated with symptomatic progression but rarely rupture in follow-up. In this retrospective study, surgical treatment outcomes did not significantly differ from aneurysms treated conservatively.
Patient Care: Understanding the natural history of vertebrobasilar aneurysms will improve treatment selection and patient outcome.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the natural history of unruptured fusiform vertebrobasilar aneurysms and 2) discuss surgical vs. conservative treatment for these lesions.