Subcutaneous incision of the fistula tract and internal sphincterotomy: A novel surgical procedure for transsphincteric anal fistula

In December's edition of Colorectal Disease, Sahara et al. [1] present a novel surgical procedure for the treatment of transsphincteric anal fistula, which they call subcutaneous incision of the fistula tract and internal sphincterotomy (SIFTIS). The authors hypothesized that socalled deep crypts (primary anal fistula openings comprising wide and thick pockets) are responsible for nonhealing of the fistula. The aim of the proposed technique is to eradicate these deep crypts. SIFTIS flattens deep crypts by dissecting fistula tracts and fibrous subepithelial tissue. Basically, the external fistula opening was excised and drained optimally. Furthermore, an incision was made at the anoderm and meticulous dissection was performed in the submucosal layer. The internal anal sphincter was identified and sharp sphincterotomy was performed. Then, the fistula was identified and divided. It should be noted that the fistula was not ligated and that the internal opening was not closed. In this study, including 151 patients over a 2year period, primary endpoint was healing rate at 16 weeks postoperatively, defined as complete epithelialization of the surgical wound. SIFTIS had primary healing rate of 85%, at a median healing time of 6 weeks. After secondary surgery to treat recurrent and remnant fistulas, overall success rate was 98%. This study is interesting, because it typically describes the initial stages (and outcome) of a new technique to treat a difficult surgical problem. It is a retrospective study from a single center evaluating shortterm outcome from a new surgical technique in a selected group of patients. It should not be a surprise that success rate was high (primary healing rate 85%) and complication rate was close to zero in this cohort. Moreover, clinical continence status was good and was only evaluated by an interview, without further scoring or measuring incontinence. The quest to find the optimal technique to close and heal a transsphincteric anal fistula has been long and is still ongoing. A huge variety of surgical techniques have been explored and both shortand longterm outcome have been published. Rectal advancement flaps, fistulectomy, fistulotomy, anal collagen plugs, fibrin glue sealants, ligation of the fistula tract, videoassisted anal fistula treatment, fistula tract laser closure, overthescope clips, or a combination of abovementioned techniques have all been tried to optimize outcome and prevent fistula recurrence [2, 3]. History of anal fistula surgery has shown that almost all studies describing and evaluating new surgical techniques for anal fistula treatment initially have excellent results. Unfortunately, almost all techniques started with success rates around 90%, which then later decreased to around 50%– 60% [4– 8]. Moreover, secondary surgery rates increased to treat persistent and/or recurrent perianal fistulas. Thus, I might be a little sceptic when I analyzed results of the present study. For now, the authors should be congratulated with these excellent and promising results, but time will tell whether this technique is reproducible, generalisable, and whether it produces similar outcomes in other cohorts of patients in prospective studies.