Interpeduncular basilar aneurysm causing progressive locked-in syndrome: to coil or not to coil.

Dear Sir, We describe a patient with progressive locked-in syndrome due to a giant interpeduncular basilar aneurysm that initially underwent coiling and eventually clipping. The case is unusual because the locked-in syndrome was caused by severe midbrain compression rather than an ischemic infarction of the basis pontis, had a gradual rather than abrupt onset and was accompanied by vertical rather than horizontal gaze palsy. Some improvement occurred after the neck of the aneurysm underwent surgical clipping. Based on this case and a review of the literature, we suggest that patients with giant aneurysms in critical locations be treated initially with surgical clipping rather than coiling.