Retreatments are part of the evaluation of device performance … but have to be analyzed separately.

We want to thank the correspondents1 for pointing out an error in our article entitled ‘Aneurysm treatment with WEB in the cumulative population of two prospective, multicenter series: 3- year follow-up’2 and JNIS for giving us the opportunity to respond to their critique. First, we must address the error in the legend to Figure 3 in our article.1 2 This legend should read as follows: ‘Unruptured middle cerebral artery aneurysm. (a) DSA (frontal view) prior to intervention. (b) 1-year follow-up radiograph showing retraction of the WEB. (c) 1-year follow-up DSA showing the resulting aneurysm recurrence. (d) and (e) Post-retreatment images performed using stents and coils.’ We are sorry that the previous legend’s text was ambiguous; the images were chosen to show the cause of failure and the retreatment method. We agree that scientific controversies are a necessary part of scientific progress, and uncorrected untruths are not the right way to build new scientific knowledge. Intrasaccular flow disruption with the Woven EndoBridge (WEB) device (Microvention/Sequent, Aliso Viejo, CA, USA) is an innovative treatment in the sense that the concept and the design of the device is new compared with existing endovascular tools. This treatment modality was introduced in Europe (after CE mark) in 2010 for the treatment of complex aneurysms (wide-neck bifurcation aneurysms (WNBAs)) and clinical evaluation started with the WEBCAST (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy) study (first inclusion in December 2011).3 This evaluation was conducted with the first generation of the device (WEB-DL, dual-layer) and required operators to develop experience during the …