Balloon Dilation of Intrinsic Small Bowel Strictures: Still Doubts About Its Efficacy?

Progression towards complicated disease has been the fate most patients with small bowel Crohn’s disease [CD] have been facing. Although new treatment options, predominantly the anti-tumour necrosis factor [anti-TNF] monoclonals, have markedly influenced our therapeutic strategies, they have also all but eliminated the need for surgical interventions aimed at alleviating strictures and perforations. Conservative surgical resections have been the mainstay intervention for perforating disease, but for strictures both endoscopic and surgical strictureplasties have been developed.1 Although endoscopic dilations with rigid through-the-scope balloons mainly delay surgery,2 they do not carry the risk of certain complications specific to surgery such as wound infections and prolonged ileus. Major complications, namely significant bleeding and perforation, associated with endoscopic dilation are only observed in 5% of procedures and do not appear to be more prevalent than anastomotic leaks after surgery.3,4 Almost all evidence to support strictureplasty, both surgical and endoscopic, stems from retrospective cohort studies with inherent selection bias, but results are consistent across the board. Most of the reported evidence on the use of endoscopic dilations in patients with CD-related strictures pertains to stenosis at the ileocolonic anastomosis or at the ileocecal valve, both predilection sites for symptomatic strictures. The paper by Hirai et al. in this issue of the journal reports on a prospective cohort study focused on outcomes of endoscopic treatment of intrinsic small bowel strictures. The patients, all with obstructive symptoms, were recruited at 23 Japanese centres across the country. The authors were able to identify 112 patients who consented to the cohort study, although only 95 were evaluated for the prespecified outcomes due to protocol violations or failure to provide data on the primary outcome in the other 17. The population studied was, not surprisingly, skewed towards ileal disease location and previous CD-related surgery. Almost half the patients were receiving biologics and/or immunosuppressants. Single or double balloon endoscopy was used to reach the strictures, of which the vast majority (77%) were de novo and less than 3 cm long. After confirmation of the stricture sites with endoscopy and/or imaging, through-the-scope rigid balloons were used for dilation, but standardization of the diameter of these balloons was not part of this study (mean diameters of 14 and 15 mm are mentioned as well as 8–10 mm). Instead, the balloon diameter size was left to the physician’s discretion. Passage of the endoscope was possible in 77% of procedures after dilation, and the primary outcome, an improvement of the obstructive symptoms judged on a visual analogue score and no medical or surgical rescue therapy, was reached by 69% of patients. No predictors of short-term success were identified, even if there were non-significant trends linking large balloon diameters to better short-term outcomes. Long-term outcomes such as the long-term risk of surgery and repeat endoscopic dilation were pre-specified, but results were not provided. Safety of the balloon dilations was acceptable, with a 5% major complication rate of which most were bleeds and none required surgery. This is in line with a recent meta-analysis of mainly ilecolonic dilations.3 It is not easy to compare the results of this cohort with other previously reported data as most of the evidence published before comes also from Japan and was generated by the some of the investigators involved in the current paper. Hirai et al., also the first author on this paper, recently reported their experience from Fukuoka University Hospital. In 65 patients they achieved an 80% immediate success rate and 73% of patients were surgery-free after 3 years.5 The complication rate of 9% was potentially higher than in the present paper. A recent meta-analysis by Arulanandan et al. identified 171 patients from mainly retrospective cohort studies, who underwent endoscopic dilation in the small bowel for CD strictures that were reached by balloon-assisted enteroscopy.6 The outcomes from the assembled literature evidence were similar to those reported by Hirai et al. in this issue of JCC, with technical success in 166/171 patients, although the perforation rate of 3% (5/166) was higher. This meta-analysis found the need for re-dilation to be 43% and the need for surgery to be 25% after endoscopic dilation. Again, more than half of the studies identified in the meta-analysis reported on fewer than ten patients with CD. Of course there are technical challenges to balloon-assisted enteroscopy and the procedure is mainly in the hands of therapeutic endoscopists, who are often not directly involved in the care of the patients with inflammatory bowel disease [IBD]. This may hinder referrals. Also, it should not come as a surprise that Japan is leading the field in this respect as confidence around balloon-assisted enteroscopy is higher than in other countries. Nevertheless, it took the Japanese physicians 2 years to recruit 95 suitable patients in 23 centres across a densely populated country with a high incidence of IBD. This indicates that even in Japan balloon-assisted enteroscopy with dilation is a rare procedure or that, as in all prospective cohorts, there may have been a selection of patients included. Finally, the primary endpoint of any degree of short-term symptom improvement measured with a visual analogue scale in an open label cohort was not very stringent. For that reason, the long-term surgery and re-dilation rates from this interesting cohort are eagerly awaited. For this paper to really change clinical practice in other countries, the long-term outcomes need to be compared to surgical strictureplasty, which also has proven to be a relatively low-risk–high-gain intervention for short or intermediate length intrinsic small bowel strictures. The authors argue that randomizing patients to either surgical or endoscopic strictureplasty is associated with ethical issues and we agree to some extent, but a case-controlled cohort matched for important variables may provide some of the answers. In addition, these results highlight the need for centralization of expertise in enteroscopy and small bowel dilation given the low volume. In summary, this study shows that two-thirds of patients experience short-term benefit from endoscopic dilation with balloon-assisted enteroscopy. However, two main caveats preclude implementation in clinical practice around the world. First, a high level of technical expertise is required to reach the strictures. Second no long-term data on avoidance of surgery and new dilations nor a comparison with a surgical strictureplasty cohort is offered. TB and GVA both contributed to the writing and the editing of this editorial. The authors declare no conflict of interest.

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