Reply:

We would like to thank Armoiry and colleagues for their critical analysis of our recently published systematic review. As the authors point out, there are a number of challenges to performing systematic reviews and meta-analyses of the literature in the field of interventional neuroradiology and neurosurgery.¹ This is especially true because many authors report single-center series and then a portion of those patients go on to be reported in large multi-institutional or multinational registries.

Regarding our inclusion of studies with overlapping populations, sometimes this is necessary in cases in which 1 study may focus on reporting outcomes at different time periods (ie, immediate posttreatment results versus long-term posttreatment results) or when studies focus on different outcomes (ie, morbidity and mortality versus angiographic outcomes). While patient populations may overlap, we do our best not to include overlapping results.

As stated by the authors, our systematic review and systematic reviews in the neurovascular literature in general are at risk of including overlapping patient populations. As we mentioned in our limitations section, though we were careful to exclude studies that had overlapping patient populations by examining the time periods studied and the institutions where the patients were treated, in some cases, articles were not clear as to whether patients included in their studies were included in prior publications.² In all such cases, we did attempt to contact the authors of articles. It is important for authors of both single-center series and large multi-institutional registries to provide information regarding the potential for overlap with prior publications.

Last, we would like to congratulate Armoiry and colleagues on their systematic review of the Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical, Aliso Viejo, California).³ Their work provides an excellent and systematic overview of the current data regarding the WEB and provides important information that should be considered by all practitioners who are treating aneurysms with this device.

• © 2017 by American Journal of Neuroradiology