Background: Rupture of spinal aneurysms is a rare cause of subarachnoid hemorrhage. These aneurysms are often associated with a variety of vascular malformations that increase blood flow in the spinal circulation or with disorders that compromise the vessel wall. However, spinal aneurysms may be isolated, not associated with any known predisposing condition. The objective of this study is to explore the possible mechanisms associated with the formation and rupture of isolated spinal aneurysms (ISAs).
Methods: We conducted a retrospective review of a series of consecutive patients admitted for a ruptured ISA. In all cases, spinal angiography confirmed the presence of a spinal aneurysm responsible for the bleeding. Particular attention was paid to medical history and symptoms before bleeding, for potential factors predisposing to their formation and rupture.
Results: Between 2008 and 2020, ten cases of spinal aneurysms were seen at our institution including 4 cases of ISA. All patients with ISA were female, and in 3 cases the aneurysm involved the territory of the posterior spinal artery. In 3 of these 4 (75%) ISA cases, there was a strikingly similar history of retching and vomiting preceding the thunderclap headache. In 1 patient, the aneurysm was surgically resected; pathologic analysis revealed a fusiform dissecting aneurysm. All 4 patients had a favorable outcome.
Conclusions: We suggest that the straining during prolonged retching and vomiting plays a role in the formation and rupture of some ISAs, possibly because of pressure spikes, increased transmural arterial pressure, and increased wall shear stress during straining.
Keywords: Aneurysm formation; Aneurysm rupture; Dissecting aneurysms; Fusiform aneurysms; Spinal aneurysms; Spinal arteries; Subarachnoid hemorrhage.
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