Endoscopic radial incision and cutting using balloonassisted enteroscopy for small intestinal stenosis related to Crohn’s disease: a pilot study

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Intest Res. 2025;.ir.2024.00143

Publication date (electronic) : 2025 January 21

doi : https://doi.org/10.5217/ir.2024.00143

Rintaro Moroi^,1, Kotaro Nochioka², Satoshi Miyata³, Hideya Iwaki¹, Hirofumi Chiba⁴, Hiroshi Nagai¹, Yusuke Shimoyama¹, Takeo Naito¹, Hisashi Shiga¹, Masaki Tosa⁵, Yoichi Kakuta¹, Shoichi Kayaba⁴, Seiichi Takahashi⁵, Yoshitaka Kinouchi¹, Atsushi Masamune¹

¹Division of Gastroenterology, Tohoku University Hospital, Sendai, Japan

²Clinical Research, Innovation and Education Center, Tohoku University Hospital, Sendai, Japan

³Graduate School of Public Health, Teikyo University, Tokyo, Japan

⁴Division of Gastroenterology, Iwate Prefectural Isawa Hospital, Oshu, Japan

⁵Division of Gastroenterology, Iwaki City Medical Center, Iwaki, Japan

Accepted October 24, 2024. Correspondence to Rintaro Moroi, Division of Gastroenterology, Tohoku University Hospital, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan. E-mail: rinta@med.tohoku.ac.jp

Received 2024 September 11; Revised 2024 October 23; Accepted 2024 October 24.

Abstract

INTRODUCTION

Benign small bowel stenosis is a common complication in clinical practice that can lead to bowel obstruction, requiring urgent intervention. Furthermore, Crohn’s disease (CD)-related mucosal healing and surgical anastomosis can cause stenosis of the small bowel [1-3]. Endoscopic balloon dilation (EBD) [4-6] and surgical intervention, including resection of stenosis [7] or strictureplasty [8], are the standard therapies for stenosis of the small bowel. However, each therapy has certain limitations, necessitating further endoscopic interventions. A previous study has reported the effectiveness of endoscopic stricturotomy using a needle knife for intestinal strictures associated with inflammatory bowel diseases [9]. In contrast, we have investigated a similar technique, known as radial incision and cutting (RIC), and demonstrated its efficacy and safety for managing lower gastrointestinal strictures [10-12]. The term “RIC” was first introduced in a study that evaluated the use of an electrosurgical knife for endoscopic stricturotomy in esophageal strictures [13]. Although the terms “RIC” and “endoscopic stricturotomy” describe closely related procedures, we adopt the term “RIC” in accordance with the report of Muto et al. [13] in this study.

RIC has several advantages, including the achievement of a relatively larger dilation compared with that achieved through EBD in some cases and improvement in patients’ subjective symptoms [10-12]. However, the main target lesions of RIC are usually limited to colonic stenosis and terminal ileal stenosis, as the working length of an endoscopic electrical knife available in Japan (IT knife nano; Olympus, Tokyo, Japan) is only 1,950 mm, which is not compatible with balloon-assisted enteroscopy (BAE). Although many studies have investigated endoscopic stricturotomy for targeting ileo-colonic anastomosis [9,14,15], current knowledge regarding RIC for stenosis of the small intestine necessitating BAE remains limited. We hypothesized that performing RIC for small intestinal strictures that cannot be reached by a colonoscope is safe, feasible, and effective in patients with CD, and performing RIC in patients with small intestinal strictures may be highly beneficial.

Therefore, this pilot study aimed to investigate the safety, feasibility, and efficacy of RIC for benign stenosis of the small intestine using BAE and a long electric knife, which is not commercially approved in Japan.

METHODS

3. Trial Intervention

The RIC procedure was performed as described previously [10,11]. Fig. 1 presents a representative case of RIC (Supplementary Video 1). We contracted a collaborative research agreement with Fujifilm Corporation and used a long electrosurgical knife (FlushKnife BTS long type; Fujifilm, Tokyo, Japan) with a working length of 2,300 mm and compatibility with BAE. Notably, this long electrosurgical knife is not yet commercially approved in Japan. The settings of the electrosurgical unit (VIO300D; ERBE Electromedicine GmbH, Tübingen, Germany) were the same as those used for endoscopic submucosal dissection of colorectal tumors (ENDO CUT I effect 3, duration 2, cutting duration 2, Swift COAG effect 3, 45 W). Endoscopists who had performed > 50 cases of colorectal endoscopic submucosal dissection conducted RICs.

Fig. 1.

Procedure of radial incision and cutting (RIC) in a male in his 40s with Crohn’s disease having small intestinal stenosis due to mucosal healing of Crohn’s disease. (A) Primary stenosis in the small intestine. First radial incision (yellow allow). (B) Just after first radial incision. (C) Subsequent horizontal cut (white allow) after radial incision. Regarding the depth of incision, several incisions should be performed with caution not to incise too deep. (D) Completion of RIC. We repeated several radial incisions and horizontal cuttings and completed RIC. An enteroscope could pass through the dilation site. When executing the horizontal cut, slightly angling the scope toward the muscle layer can facilitate smoother manipulation. (E) Fluoroscopy before RIC. Visible stenosis (orange allow). (F) Fluoroscopy just after the completion of RIC showing adequate dilation and no leakage (orange allow).

The protocol for this study allows for 3 potential reintervention options (EBD, surgery, or re-RIC) in cases of restenosis. The choice of reintervention is determined in consultation with the participant, taking their preferences into consideration.

RESULTS

1. Patient Characteristics

Table 1 presents the baseline characteristics of the study participants. Although patients with other benign diseases were eligible for participation, all study participants had CD. The mean age of the patients was 31.7 years, and they had CD for a mean duration of 13.6 years. Three and 7 patients had primary and secondary stenosis, respectively. Furthermore, 3 patients had a history of EBD, and 1 had stricture ulceration. The length of stenosis in all participants measured 1cm or less. The treatment for CD comprised infliximab, azathioprine, 5-aminosalicylic acid, and central parenteral nutrition for 4, 3, 2, and 1 patients, respectively. Notably, 2 patients did not receive any treatment.

Table 1.

Baseline Characteristics of Study Population

2. Primary Endpoint

We conducted 12 sessions of RIC for 10 lesions. Table 2 shows the safety profile for 1 month after RIC for small bowel strictures. No patients experienced delayed bleeding and perforation. Thirty-four days after RIC, CD worsened in 1 patient and caused restenosis, which led to bowel obstruction; the patient underwent surgical bowel resection.

Table 2.

Adverse Events within the 1 Month after RIC (n=12)

3. Short-term Outcomes of RIC of the Small Intestine Using BAE

Table 3 presents the short-term outcomes following RIC of the small intestine. The technical success rate for RIC was 100% (12/12). The mean procedural time for RIC was 9.6 minutes, and the mean duration of hospitalization after RIC was 14.4 days.

Table 3.

Short-term Results of RIC

4. Long-term Outcomes of RIC of the Small Intestine Using BAE

Fig. 2 shows the long-term outcomes following RIC of the small intestine. The cumulative restenosis-, reintervention-, and surgery-free rates 1 year after RIC were 67.5%, 78.7%, and 90.0%, respectively. Three patients underwent reintervention, including EBD (1 patient) and re-RIC (2 patients), because of restenosis. Two months after RIC, 1 patient underwent intestinal resection because of refractory restenosis that was resistant to semi-urgent EBD (the participant hoped for surgery instead of performing re-RIC).

Fig. 2.

Long-term prognosis of radial incision and cutting for stenosis of the small intestine. Graphs depicting the cumulative (A) restenosis-, (B) reintervention-, and (C) surgery-free rates.

5. Improvement in Subjective Symptoms Following RIC

Improvements in subjective symptoms are summarized in Fig. 3. The symptoms, including abdominal pain (43.6 mm vs. 3.8 mm, P= 0.008), abdominal bloating (46.5 mm vs. 7.9 mm, P= 0.007), nausea (43.8 mm vs. 1.6 mm, P= 0.009), and difficulties in defecation (37.1 mm vs. 5.4 mm, P= 0.022), significantly improved after RIC.

Fig. 3.

Subjective symptoms before and 4 weeks after radial incision and cutting (RIC).

DISCUSSION

In this pilot study, we investigated the safety and efficacy of RIC for small intestine stenosis using a long electrosurgical knife and BAE. RIC for stenosis of the small intestine demonstrated a low complication rate and high technical success rate and was associated with improved subjective symptoms.

Our results indicated the safety of RIC for the small intestine. Our previous studies have reported a relatively high delayed bleeding rate of approximately 20% [10-12]. Although our previous studies have also shown a relatively high delayed bleeding rate, endoscopic hemostasis was achieved in all cases. However, none of the patients in the present study experienced delayed bleeding after RIC. Furthermore, some previous studies have reported ileocolonic anastomotic strictures due to CD in all patients with delayed bleeding after RIC [10-12]. Conversely, the cases with secondary strictures in this study were all ileal-to-ileal anastomoses; this may be the reason for nonoccurrence of delayed bleeding in this study. Furthermore, no patients experienced perforation in this study. Additionally, a high technical success rate (approximately 100%) and low perforation rate (0%–3.7%) have been reported previously [10-12]. A retrospective study investigating endoscopic stricturotomy for small bowel stenosis using BAE exhibited similar results of high technical success and low adverse event rates [18]. Nevertheless, further investigations with larger sample sizes are necessary to precisely evaluate the safety of RIC.

The short-term outcomes of RIC using BAE were beneficial, with a technical success rate of 100% and a relatively short procedural time. Notably, RIC using BAE may be more difficult to perform than EBD, and the technical success rate may depend on the operator’s expertise. Furthermore, significant improvement in subjective symptoms, as observed in this study, is another advantage of RIC. However, this is a pilot study with a single-arm design. Further investigations are required to elucidate the clinical advantages of RIC in comparison with other interventions.

Considering RIC for stenosis of the small intestine is controversial, and in the context of the underlying etiology of stricture formation, only patients with CD were included in this study. RIC has been previously performed for various etiologies, including anastomotic stricture due to colorectal cancer and mucosal healing of ischemic and ulcerative colitis [11,12]. RIC for stenosis in the small intestine may be adapted for various etiologies, including CD. Regarding stricture length, we included patients with stricture length of ≤ 1 cm. A relatively short stricture length is desirable for RIC, as an incisional procedure cannot be performed for a longer stricture. Notably, RIC is not expected to dilate strictures of > 2 cm in length, and EBD may be suitable for such long strictures. However, RIC has the potential to dilate EBD-resistant stenosis by incising severe fibrosis using an electrosurgical knife.

The long-term outcomes of RIC for stenosis in the small intestine were favorable, with the cumulative reintervention-and surgery-free rates at 1 year after RIC of 78.7% and 90.0%, respectively. The reintervention-free rate in this study was higher than those of our previous studies (55.8%–63.7%) [11,12] which included colonic and terminal ileal strictures. Furthermore, the surgery-free rate at 1 year after RIC was comparable to or slightly higher than those reported for EBD for small intestine using BAE (63.1%–87.3%) [19,20]. However, the etiologies of stricture formation differed between the present and previous studies. Therefore, studies including relatively larger cohorts are required to determine the etiologies for which RIC can be performed.

The main aim of endoscopic dilation for the small intestine is to avoid surgery to the extent possible. Considering the low complication and high technical success rate observed in this study, RIC using a long knife and BAE could be an alternative surgical intervention for small intestinal stenosis. However, we did not directly compare the effectiveness of RIC with EBD in symptom relief. Further research, including comparative studies between RIC and EBD, is needed to more accurately assess the feasibility and effectiveness of RIC.

This study has some limitations. First, this prospective study was a single-center pilot study with a small number of participants. Notably, the sample size in this study was too small to determine the safety and efficacy of RIC for stenosis of the small intestine. Second, as RIC is a novel dilation method, the acquisition of technical skills for RIC is necessary, necessitating further investigations with large cohorts to validate the safety, efficacy, and feasibility of RIC for stenosis of the small intestine. Third, the absence of a sham procedure group introduces the potential for bias. Without a sham intervention, a placebo effect may have occurred, whereby participants could have experienced symptom relief due to psychological factors rather than the actual effects of the intervention.

In conclusion, RIC for stenosis of the small intestine using a long electrosurgical knife and BAE has the potential to be safe, effective, and feasible modality for relieving symptoms. Further investigations are warranted.

Supplementary Material

Supplementary materials are available at the Intestinal Research website (https://www.irjournal.org).

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