Intentional sparing of daughter sac from coil packing in the embolization of aneurysms causing the third cranial nerve palsy : initial clinical and radiological results

Objective: Cerebral aneurysms which cause oculomotor nerve [cranial nerve (CN) III] palsy, are frequently found with a daughter sac of the aneurysm dome. We assumed that CN III might be compressed by the daughter sac and it would be more helpful not to fill the daughter sac with coils than vice versa during endosaccular embolization for recovering from CN III palsy, because it may give a greater chance for the daughter sac to shrink by itself later. We reviewed the initial results of our experiences of such cases.

Methods: Among 9 aneurysms accompanied by CN III palsy, 7 (6 unruptured, 1 ruptured) showed a daughter sac. We tried to fill the main dome completely and spare the daughter sac from coil filling to increase the possibility of decompression. We evaluated the short-term effectiveness of this concept using medical records and angiograms.

Results: After initial embolization, all of CN III palsy caused by unruptured aneurysms (6/6) resolved completely after various periods (3-90 days) of time. No adverse effects were noted during and after the procedures except for one case of harmless coil stretching during coil filling using double microcatheter.

Conclusion: During the coil embolization of the cerebral aneurysm causing CN III palsy, sparing the daughter sac from coil packing while tightly packing the main dome, can be helpful in increasing the effectiveness of decompression. However, a long-term follow-up will be required.