Ruptured aneurysm with delayed distal coil migration requiring surgical treatment. Case report.

A 64-year-old woman with subarachnoid hemorrhage manifesting as sudden onset of severe headache visited our hospital on post-onset day 8. Diagnostic cerebral digital subtraction angiography revealed an aneurysm located at the left internal carotid-anterior choroidal artery with diffuse cerebral arterial spasm. Coil embolization was selected because of diffuse spasm in spite of parent artery elongation at the extra-cranial portion. A small portion of the coil migrated to the parent artery, but coil embolization was successfully completed. The patient developed delayed spasm, which required arterial fasudil hydrochloride injection. After the acute phase of subarachnoid hemorrhage, the patient's symptoms disappeared. However, on day 24 after subarachnoid hemorrhage, the patient showed right hemiparesis and total aphasia, and skull radiography revealed that the migrated coil had moved into the M1 portion of the left middle cerebral artery. Craniotomy was performed to retrieve the coil and clip the aneurysm neck. However, the migrated coil could not be retrieved because of adhesion to the arterial wall. Delayed coil migration is very rare in the chronic phase.