Introduction: Migration of a coil during endovascular treatment of intracranial aneurysm occurs in 2-6% of cases, and the frequency of its occurrence has not significantly changed over the past 20 years. The consequences of coil migration vary significantly from minor flow alterations of the parent artery which are asymptomatic to thromboembolic occlusion of large intracranial vessels resulting in massive infarcts.

Methods: We performed a comprehensive literature review and identified 37 reported cases of migrated coil retrieval consisting of ten case reports and six case series.

Results: The majority of aneurysms presented with rupture (65%) and were located in the anterior circulation (70%). The endovascular treatment approaches were coil embolization alone (57%), stent-assisted coiling (26%), and balloon remodeling (17%). Endovascular retrieval was performed with guidewires or microwires, nonangled and Alligator Retrieval devices, L5 and X6 Merci devices, loop and Goose Neck snares, and Solitaire stent and Catch Plus stentriever devices. There was a single report of microsurgical extraction following failed endovascular removal and three cases of coil fracture in which the coil fragments were secured to the vessel walls with Cerebrence or Neuroform stents. For minor coil protrusion or prolapse, we recommend conservative management with antiplatelet therapy with or without short-term anticoagulation. Major coil displacement must be treated aggressively to avoid significant neurological morbidity and mortality.

Conclusions: As the number of endovascular aneurysm treatments continues to rise and new approaches for successful occlusion continue to be developed, it is critically important that the proper management of intraprocedural coil migration becomes more clearly defined.

Patient Care: As endovascular approaches for the treatment of intracranial aneurysms have become increasingly widespread, the reported rates of intraprocedural coil migration have not significantly changed. Therefore, with a likely increasing incidence of intraprocedural coil migration, the proper management of this complication has significant implications in improving patient outcomes from endovascular aneurysm treatment.

Learning Objectives: By the conclusion of this session, participants should be able to 1) Describe the importance of properly managing intraprocedural coil migration during endovascular aneurysm treatment, 2) Discuss, in small groups the various techniques and devices available for retrieval of errant coils, and 3) Identify an effective treatment for intraprocedural coil migration.

References: 1. Casasco AE, Aymard A, Gobin YP, Houdart E, Rogopoulos A, George B, Hodes JE, Cophignon J, and Merland JJ: Selective endovascular treatment of 71 intracranial aneurysms with platinum coils. J Neurosurg 79: 3-10, 1993. 2. Dinc H, Kuzeyli K, Kosucu P, Sari A, and Cekirge S: Retrieval of prolapsed coils during endovascular treatment of cerebral aneurysms. Neuroradiology 48: 269-72, 2006. 3. Fiorella D, Albuquerque FC, Deshmukh VR, and McDougall CG: Monorail snare technique for the recovery of stretched platinum coils: technical case report. Neurosurgery 57: E210; discussion E210, 2005. 4. Gao BL, Li MH, Wang YL, and Fang C: Delayed coil migration from a small wide-necked aneurysm after stent-assisted embolization: case report and literature review. Neuroradiology 48: 333-7, 2006. 5. Guglielmi G, Vinuela F, Sepetka I, and Macellari V: Electrothrombosis of saccular aneurysms via endovascular approach. Part 1: Electrochemical basis, technique, and experimental results. J Neurosurg 75: 1-7, 1991. 6. Guglielmi G, Vinuela F, Dion J, and Duckwiler G: Electrothrombosis of saccular aneurysms via endovascular approach. Part 2: Preliminary clinical experience. J Neurosurg 75: 8-14, 1991. 7. Henkes H, Fischer S, Weber W, Miloslavski E, Felber S, Brew S, and Kuehne D: Endovascular coil occlusion of 1811 intracranial aneurysms: early angiographic and clinical results. Neurosurgery 54: 268-80; discussion 280-5, 2004. 8. Henkes H, Lowens S, Preiss H, Reinartz J, Miloslavski E, and Kuhne D: A new device for endovascular coil retrieval from intracranial vessels: alligator retrieval device. AJNR Am J Neuroradiol 27: 327-9, 2006. 9. Hopf-Jensen S, Hensler HM, Preiss M, and Muller-Hulsbeck S: Solitaire(R) stent for endovascular coil retrieval. J Clin Neurosci 20: 884-6, 2013. 10. Koseoglu K, Parildar M, Oran I, and Memis A: Retrieval of intravascular foreign bodies with goose neck snare. Eur J Radiol 49: 281-5, 2004. 11. Lee CY: Use of wire as a snare for endovascular retrieval of displaced or stretched coils: rescue from a technical complication. Neuroradiology 53: 31-5, 2011. 12. Leslie-Mazwi TM, Heddier M, Nordmeyer H, Stauder M, Velasco A, Mosimann PJ, and Chapot R: Stent Retriever Use for Retrieval of Displaced Microcoils: A Consecutive Case Series. AJNR Am J Neuroradiol 2013. 13. Li H, Pan R, Wang H, Rong X, Yin Z, Milgrom DP, Shi X, Tang Y, and Peng Y: Clipping versus coiling for ruptured intracranial aneurysms: a systematic review and meta-analysis. Stroke 44: 29-37, 2013. 14. Molyneux A, Kerr R, Stratton I, Sandercock P, Clarke M, Shrimpton J, and Holman R: International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised trial. Lancet 360: 1267-74, 2002. 15. Nogueira RG, Lutsep HL, Gupta R, Jovin TG, Albers GW, Walker GA, Liebeskind DS, and Smith WS: Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial. Lancet 380: 1231-40, 2012. 16. O'Hare A, Brennan P, and Thornton J: Retrieval of a Migrated Coil Using an X6 MERCI Device. Interv Neuroradiol 15: 99-102, 2009. 17. O'Hare AM, Rogopoulos AM, Stracke PC, and Chapot RG: Retrieval of displaced coil using a Solitaire((R)) stent. Clin Neuroradiol 20: 251-4, 2010. 18. Phatouros CC, McConachie NS, and Jaspan T: Post-procedure migration of Guglielmi detachable coils and Mechanical detachable spirals. Neuroradiology 41: 324-7, 1999. 19. Prestigiacomo CJ, Fidlow K, and Pile-Spellman J: Retrieval of a fractured Guglielmi detachable coil with use of the Goose Neck snare "twist" technique. J Vasc Interv Radiol 10: 1243-7, 1999. 20. Raftopoulos C, Goffette P, Billa RF, and Mathurin P: Transvascular coil hooking procedure to retrieve an unraveled Guglielmi detachable coil: technical note. Neurosurgery 50: 912-4; discussion 914-5, 2002. 21. Saver JL, Jahan R, Levy EI, Jovin TG, Baxter B, Nogueira RG, Clark W, Budzik R, and Zaidat OO: Solitaire flow restoration device versus the Merci Retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial. Lancet 380: 1241-9, 2012. 22. Schutz A, Solymosi L, Vince GH, and Bendszus M: Proximal stent fixation of fractured coils: technical note. Neuroradiology 47: 874-8, 2005. 23. Standard SC, Chavis TD, Wakhloo AK, Ahuja A, Guterman LR, and Hopkins LN: Retrieval of a Guglielmi detachable coil after unraveling and fracture: case report and experimental results. Neurosurgery 35: 994-8; discussion 999, 1994. 24. Vora N, Thomas A, Germanwala A, Jovin T, and Horowitz M: Retrieval of a displaced detachable coil and intracranial stent with an L5 Merci Retriever during endovascular embolization of an intracranial aneurysm. J Neuroimaging 18: 81-4, 2008. 25. Watanabe A, Hirano K, Mizukawa K, Kamada M, Okamura H, Suzuki Y, and Ishii R: Retrieval of a migrated detachable coil--case report. Neurol Med Chir (Tokyo) 35: 247-50, 1995. 26. White PM, Lewis SC, Nahser H, Sellar RJ, Goddard T, and Gholkar A: HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS trial): procedural safety and operator-assessed efficacy results. AJNR Am J Neuroradiol 29: 217-23, 2008. 27. Zoarski GH, Bear HM, Clouston JC, and Ragheb J: Endovascular extraction of malpositioned fibered platinum microcoils from the aneurysm sac during endovascular therapy. AJNR Am J Neuroradiol 18: 691-5, 1997.