Comment on: Easy clip to treat anal fistula tracts: a word of caution by M. Gautier et al.

Abstract

Dear Editor: We would like to comment on the paper by Gauthier and colleagues on OTSC clipping in the treatment of anal fistula. The authors present their experience collected at multiple sites with this new surgical procedure, coming to negative conclusions about its effectiveness. We appreciate the report. Having been the developers of this procedure and in the knowledge of data published by our and other groups about this technique, we however cannot agree with the way Gauthier et al. present their experience. First of all, there is some lack of definition in fundamental terminology. The title of the paper and the conclusions drawn refer to anal fistula. However, 41 % (7/17) of patients had recto-vaginal fistulae, which is a different disease entity concerning etiology, course, and treatment. Success rates of recto-vaginal fistula surgery are significantly lower when compared to anal fistulae: for local closure techniques, including advancement flaps, the literature reports success rates of one third and even less. The case group presented by Gauthier is suffering from a strong selection bias, as the authors point out themselves. Besides the 41 % of recto-vaginal cases, 35 % (6/17) had inflammatory bowel disease. It is known from literature that up to two thirds of Crohn’s patients who undergo fistula surgery have poor wound healing and persistent complications, due to the underlying inflammatory condition. Thus, the complication rate and profile reported by Gauthier is in the range of what needs to be expected in the studied patient population with 64 % (11/17) of patients having recto-vaginal fistula location, Crohn’s disease, or both. It also remains unclear whether the patients had prior surgery and a recurrent fistula before treated with OTSC, which would be relevant information to judge the procedural success rate. Only 35 % (6/17) of the patients presented apparently suffered from typical crytoglandular anal fistula; the rest were of other etiology. Thus, the patient group studied does not represent the core of the indication spectrum for OTSC clipping but is rather at the extreme margin of what this procedure is indicated for. The rationale for such a clinical investigation as presented here remains unclear. As it is a common scientific practice, new procedures shall be evaluated in the core of their indication range first and not in extreme cases which are borderline indications. The authors discuss a clip-induced devascularization of the captured tissue with consecutive persistency of the fistula. However, literature about clip application on evenmore fragile tissue, such as bowel, has not reported on such an effect. The OTSC clip is widely used in flexible endoscopy since years. Research by numerous independent authors has demonstrated that the clip geometry allows sufficient microperfusion between the teeth of the closed clip to prevent ischemia. The most striking problem of the case series presented by Gauthier is the enormous rate of primary technical failure, meaning unsuccessful primary closure of the fistula orifice with the OTSC clip. Seventy-six percent of patients (13/17) are reported to have had continuing discharge from the fistula. This means that the clip has apparently not been properly placed during surgery or the orifice may have been too large or anatomically unsuitable to be closed by clips. The reported clinical success rate of only 12 % must be seen in the context This article is a commentary to http://dx.doi.org/10.1007/s00384-015-2146-5