Endovascular treatment of previously clipped aneurysms: continued evolution of hybrid neurosurgery

The optimal management of residual or recurrent clipped aneurysms is infrequently addressed in the literature.

We reviewed our endovascular database from January 1998 to May 2016 to identify patients with clipped aneurysms undergoing subsequent endovascular treatment, evaluating treatment approach, and clinical and angiographic outcomes.

60 patients underwent endovascular treatment of residual/recurrent clipped aneurysms; 7 rebled prior to endovascular therapy. Treatment was via coiling alone (n=25, 42%), stent assisted coiling (n=15, 25%), balloon assisted coiling (n=8, 13%), flow diversion (n=8, 13%), stenting alone (n=3, 5%), or flow diversion with coiling (n=1, 2%). The procedural permanent neurological morbidity and mortality rates were 3% and 2%, respectively. Over a clinical follow-up of 253.4 patient years (median 3.9 years), there was one rebleed in a patient who had declined further treatment. For 43 patients with at least 1 month of digital subtraction angiographic follow-up (median 3.4 years), complete aneurysm occlusion was seen in 79% of cases. Neck remnants were observed in 14%, and stable small dome remnants were observed in 7% of cases. In a subgroup of 18 patients with 'clip induced' narrow neck aneurysms, all domes were initially coil occluded (Raymond 1 or 2); there was no permanent procedural morbidity and no aneurysms required retreatment or recanalized over a median follow-up of 3.9 years.

Endovascular treatment of residual or recurrent clipped aneurysms is an excellent treatment approach in well selected patients; 'clip induced' narrow neck aneurysms fare particularly well after treatment both angiographically and clinically.