Introduction: Successful transcatheter endovascular coiling of tiny saccular intracranial aneurysms (=3mm in greatest dimension) can be technically challenging. The fine balance between deploying intra-saccular coils with enough purchase that they do not migrate into the parent artery while at the same time using little enough force to prevent against aneurysm perforation is highlighted by high complication rates involving both intraprocedural rupture and parent vessel thrombosis.(1-6) Recent technological advances in coil technology have allowed neuroendovascular practitioners to safely treat ruptured tiny saccular aneurysms.(1,3, 8-10) The purpose of this study was to report the technical feasibility, clinical results, complications, and angiographic outcomes from coiling ruptured aneurysms =3mm from a single-center experience.

Methods: We performed a retrospective review of 16 patients with 16 ruptured aneurysms from a single academic tertiary care practice between May 2013 and June 2015. Periprocedural and clinical outcome data including Glasgow Coma Scale, Hunt and Hess scores, aneurysm size, complications, aneurysm occlusion rates, and post procedural modified Rankin scale (mRS) were collected. The coils utilized in this study were Stryker Nano coils and Target Helical Ultra coils (Stryker Neurovascular). The microcatheters included SL-10 (Stryker Neurovascular), Prowler-10 (Codman), Headway (Microvention/Terumo), and Prowler 14 (Codman).

Results: The mean aneurysm size was 2.45mm. There was complete aneurysm occlusion in 10 of 16 patients (62.5%), with the remaining 6 (37.5%) having a small neck remnant. There were 2 intraprocedural ruptures (12.5%) and no coil migrations or parent artery thromboses. 8 of 16 patients (50%) had an modified Rankin Scale (mRS) of 0 and there was 1 death. There were no aneurysm recurrences among occluded patients (mean follow up of 115 days) and there were no retreatments among those with neck remnants.

Conclusions: Coiling of ruptured aneurysms =3mm is feasible with high occlusion rates and low complication rates.

Patient Care: Expanding the repertoire of neuroendovascular practitioners to allow successful and reliable treatment of small intracranial aneurysms is an important addition. Successful techniques for the treatment of small ruptured intracranial aneurysms represent an advance in endovascular technology that should be utilized when clinically appropriate.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of weighing considerations for coiling small ruptured intracranial aneurysms, 2) Discuss, in small groups, the possible options for treating small ruptured aneurysms and the technical challenges it presents and 3) Identify effective treatment options for coiling small ruptured intracranial aneurysms.

References: 1. Zhao R, Shen J, Huang QH, et al. Endovascular treatment of ruptured tiny, wide-necked posterior communicating artery aneurysms using a modified stent-assisted coiling technique. J Clin Neurosci 2013;20:1377-1381. 2. Brinjikji W, Lanzino G, Cloft HJ, Rabinstein A, Kallmes DF. Endovascular treatment of very small (3 mm or smaller) intracranial aneurysms: report of a consecutive series and a meta-analysis. Stroke 2010;41:116-121. 3. Chen Z, Feng H, Tang W, Liu Z, Miao H, Zhu G. Endovascular treatment of very small intracranial aneurysms. Surg Neurol 2008;70:30-35; discussion 35. 4. Goddard JK, Moran CJ, Cross DT, 3rd, Derdeyn CP. Absent relationship between the coil-embolization ratio in small aneurysms treated with a single detachable coil and outcomes. AJNR Am J Neuroradiol 2005;26:1916-1920. 5. van Rooij WJ, Keeren GJ, Peluso JP, Sluzewski M. Clinical and angiographic results of coiling of 196 very small (< or = 3 mm) intracranial aneurysms. AJNR Am J Neuroradiol 2009;30:835-839. 6. Suzuki S, Kurata A, Ohmomo T, et al. Endovascular surgery for very small ruptured intracranial aneurysms. Technical note. J Neurosurg 2006;105:777-780. 7. Gupta V, Chugh M, Jha AN, Walia BS, Vaishya S. Coil embolization of very small (2 mm or smaller) berry aneurysms: feasibility and technical issues. AJNR Am J Neuroradiol 2009;30:308-314. 8. Lu J, Liu JC, Wang LJ, Qi P, Wang DM. Tiny intracranial aneurysms: endovascular treatment by coil embolisation or sole stent deployment. Eur J Radiol 2012;81:1276-1281. 9. Lim YC, Kim BM, Shin YS, Kim SY, Chung J. Structural limitations of currently available microcatheters and coils for endovascular coiling of very small aneurysms. Neuroradiology 2008;50:423-427. 10. Hong B, Yang PF, Zhao R, et al. Endovascular treatment of ruptured tiny intracranial aneurysms. J Clin Neurosci 2011;18:655-660. 11. Pierot L, Barbe C, Spelle L, investigators A. Endovascular treatment of very small unruptured aneurysms: rate of procedural complications, clinical outcome, and anatomical results. Stroke 2010;41:2855-2859. 12. Forget TR, Jr., Benitez R, Veznedaroglu E, et al. A review of size and location of ruptured intracranial aneurysms. Neurosurgery 2001;49:1322-1325; discussion 1325-1326. 13. Molyneux AJ, Kerr RS, Yu LM, et al. International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion. Lancet 2005;366:809-817. 14. Gonzalez AM, Narata AP, Yilmaz H, et al. Blood blister-like aneurysms: single center experience and systematic literature review. Eur J Radiol 2014;83:197-205. 15. Nguyen TN, Raymond J, Guilbert F, et al. Association of endovascular therapy of very small ruptured aneurysms with higher rates of procedure-related rupture. J Neurosurg 2008;108:1088-1092. 16. Lum C, Narayanam SB, Silva L, et al. Outcome in small aneurysms (<4 mm) treated by endovascular coiling. J Neurointerv Surg 2012;4:196-198. 17. Birknes JK, Hwang SK, Pandey AS, et al. Feasibility and limitations of endovascular coil embolization of anterior communicating artery aneurysms: morphological considerations. Neurosurgery 2006;59:43-52; discussion 43-52.