Endovascular embolization of superior hypophyseal artery aneurysms.

OBJECTIVE: Internal carotid artery aneurysms arising from the superior hypophyseal artery are frequently termed paraophthalmic or paraclinoid aneurysms, but they constitute a distinct anatomic entity. They are particularly amenable to endovascular treatment.
METHODS: Between 1991 and 1995, we attempted treatment in 11 patients with superior hypophyseal artery aneurysms with Guglielmi detachable coil embolization and were successful in 10. Surgical exploration in seven of the patients was unsuccessful, three patients were considered to be at high risk for surgery or to have poor likelihood of surgical success by the referring neurosurgeon, and one patient refused operative clipping. Two aneurysms were giant (> 25 mm), three were large (10-25 mm), and six were small (< 10 mm). Of the six small aneurysms, two had wide necks (> 4 mm) and four had narrow necks (< or = 4 mm).
RESULTS: There were no technical or clinical complications related to embolization. Immediate complete aneurysm obliteration was obtained in five aneurysms, all of which were small. Four of the remaining five aneurysms had obliteration of the dome and body, leaving only a small remnant neck. The remaining semifusiform aneurysm represented our single treatment failure. Recanalization occurred in only one patient; that patient had a giant aneurysm. Nine of the 10 patients for whom embolization was successful had good or excellent clinical outcomes; there were no clinical deteriorations attributable to embolization.
CONCLUSION: We conclude that Guglielmi detachable coil embolization of superior hypophyseal artery aneurysms is an excellent treatment alternative, especially for smaller lesions.