To the Editor:
We read with great interest the recent by Al-Mufti et al,1 reviewing the various procedural complications associated with flow diverter deployment (FDD). The authors have made an invaluable addition to the neurointerventional literature by a systematic and qualitative literature review, focusing on intraprocedural complications. There has been a concerted effort by many groups to focus on causes for flow diversion failure and delayed complications. Relatively fewer investigations have focused on intraprocedural complications, and to date, these have not been so well synthesized. The authors reviewed 94 total papers in their analysis; we commend the authors on this comprehensive review and discussion.
In our recent article in Neurosurgical Focus, we analyzed our experience with prolapse of the Pipeline embolization device (PED; Medtronic Inc).2 It appears our article was published in the interval between submission and acceptance of the article by Al-Mufti et al.1 In the fast-developing field of neuroendovascular technology and clinical experience, even a systematic review will miss such updates. Our review of prolapse incidence among 413 total aneurysms treated represents the single largest review on the topic, and as it is a topic of shared interest, we wish to discuss our findings in light of this systematic review.
In the discussion of FDD prolapse, the authors share our conclusions that device migration is multifactorial, including the “accordion effect”, “watermelon seed effect”, FDD deformation, and displacement by the delivery wire or during re-capture. We did not note the effect of vertical placement of the PED in our series, though this is an interesting hypothesis that bears attention in future studies on the topic. In our series, the 3 instances of prolapse only occurred in aneurysms >2 cm. Due to the rare incidence in our series, statistical analyses about this incidence based on aneurysm size was not performed, but it is intuitive that this is a complication unique to large and giant aneurysms with very wide neck. Prior reports, as reviewed by Al-Mufti et al1 and in our article,2 had not described PED being left in situ after prolapse without rescue. As an update to our report, there has still been no adverse effect on these 2 patients with prolapsed PED left in situ at >48 mo, though they are being followed closely on antiplatelet therapy.
The techniques summarized in both our article2 and by Al-Mufti et al1 are important to study, as this rare occurrence of prolapse is likely to occur at some point in any busy practice. Being prepared and knowledgeable about the rescue strategies beforehand is the best way to provide optimal care for our patients. We congratulate the authors on their selection as an Editor's choice article and encourage others to refer to it when dealing with potential complications.
Dr Kan is a consultant for Medtronic and Styker Neurovascular. The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
1. Al-Mufti F, Amuluru K, Cohen ER, et al. Rescue therapy for procedural complications associated with deployment of flow-diverting devices in cerebral aneurysms. Oper Neurosurg. 2018;15(6):624-633.
2. Srinivasan VM, Carlson AP, Mokin M, et al. Prolapse of the Pipeline embolization device in aneurysms: incidence, management, and outcomes. Neurosurg Focus. 2017;42(6):E16.