Spontaneous thrombosis of a giant fusiform aneurysm following extracranial-intracranial bypass surgery.

The authors describe the cases of 2 patients who underwent extracranial-intracranial bypass surgery for a giant fusiform aneurysm but in whom further surgery was then not necessary because the aneurysm spontaneously thrombosed. The authors hypothesize that this thrombosis was caused by alterations in aneurysm's hemodynamics, leading to a decreased rate of blood flow in the aneurysm. In the older of the 2 cases, more than 10 years after surgery the patient has not required further surgical intervention. Spontaneous thrombosis of a giant fusiform aneurysm is a rare occurrence during extracranial-intracranial bypass, and although continual monitoring is recommended, these patients can remain stable long term.