Interventional Endoscopy in Inflammatory Bowel Disease: An Expanding Frontier

Vol. 30, Issue 2 (June 2025)

Gursimran Singh Kochhar, MD
Chief, Division of Gastroenterology, Hepatology, and Nutrition
Allegheny Health Network
Pittsburgh, Pennsylvania, USA

 

Partha Pal, MD, DNB, MRCP (UK), FASGE
Department of Medical Gastroenterology and IBD
Asian Institute of Gastroenterology
Hyderabad, Telangana, India
 

1. Introduction

Structural complications in Crohn’s disease (CD), such as strictures, fistulas, and abscesses, typically emerge 4–5 years after diagnosis. In the absence of effective anti-fibrotic therapy, interventional endoscopy and surgery remain key treatment options. Chronic inflammation leads to strictures, which may progress to upstream fistulas and abscesses. Endoscopic management includes balloon dilation, stricturotomy, or stent placement. Fistulas are endoscopically treated by addressing strictures, draining abscesses (setons, fistulotomy, endoscopic ultrasound guidance), and closure using plugs, clips, or sutures. Although initial surgery rates have declined, repeat surgeries remain common. Interventional inflammatory bowel disease (IIBD) therapies offer a minimally invasive alternative, delaying surgery by up to 6.5 years and managing post-surgical complications.¹ IIBD is an alternative, effective option to surgery in certain subsets of patients, which should be discussed with the patients albeit with a higher risk of recurrence and low risk of complications. In ulcerative colitis (UC), colitis-associated neoplasia can be treated with endoscopic resection, and pouch complications after ileal pouch-anal anastomosis may be addressed using IIBD, preserving pouch function and reducing the need for permanent surgical interventions. Moreover, IIBD can be helpful to manage post-surgical complications and can be a useful tool to bridge between surgery and medical therapy (Figure 1).

Figure 1. Interventional IBD: Therapeutic targets in Crohn’s disease and ulcerative colitis.

2. Management of IBD Strictures

2.1. Classification of IBD strictures:
IBD strictures are classified by etiology into CD, UC, and post-surgical types. UC strictures, especially proximal to the splenic flexure in long-standing disease, carry a high neoplasia risk (up to 33%). Biopsies and annual surveillance are essential, with a low threshold for surgery. CD-associated de-novo and post-surgical anastomotic strictures are good candidates for endoscopic therapy. While cancer risk is low (up to 6.8%), biopsy is advised before endotherapy both in small and large bowel strictures.² Strictures can be ulcerated, fibrotic, or mixed. Ideally, fibrotic and mixed types are suitable for endoscopic treatment, as medical therapy targets inflammation alone.

2.2. Approach to endoscopic management of Crohn's disease strictures:
Before endoscopic therapy, a thorough assessment is essential. Clinical history (fistulas, surgery, anti-TNF use), inflammatory markers, and cross-sectional imaging help characterize the stricture phenotype. Imaging assesses the number, length, location, and degree of pre-stenotic dilation. Inflammatory strictures need medical therapy, while short (≤4 cm) fibrotic or mixed strictures are ideal for endoscopic treatment. Long (>4–5 cm), multiple (>4cm), or significant pre-stenotic dilation (>5 cm) strictures typically require surgery. The BACARDI score combines clinical and genetic factors to predict surgical risk in ileal strictures.³ Even multiple strictures may be treated endoscopically in a single session if technically feasible (Figure 2).⁴

Figure 2. Approach to endoscopic therapy in Crohn’s disease strictures. B3: fistulizing disease, TNF: tumor necrosis factor, CRP: C reactive protein, FCP: fecal calprotectin, EST: endoscopic stricturotomy, EBD: Endoscopic balloon dilation, FC-SEMS- fully covered self-expanding metal stents, PC SEMS: partially covered self-expanding metal stents, LAMS: lumen apposing metal stents (adapted from Pal P, Reddy DN. Interventional endoscopy in inflammatory bowel disease: a comprehensive review. Gastroenterol Rep (Oxf). 2024 Jul 25;12).

2.3. Principles of endoscopic stricture therapy:
Endoscopic management of strictures is based on three core techniques: dilation, incision, and stenting (Figure 3, A-C). Endoscopic balloon dilation (EBD) is widely applicable and can be performed throughout the gastrointestinal tract, regardless of the stricture’s location. Endoscopic stricturotomy (ES) involves making incisions in the non-ulcerated parts of the stricture. The incisions can be made in circumferential or radial fashion. Which modality is chosen between EBD and ES depends on various factors including stricture length, location, and disease associated factors.

Figure 3. Endoscopic stricture and fistula therapy: A. Endoscopic balloon dilation, B. Endoscopic stricturotomy for rectal stricture, C. Lumen apposing stent placed for refractory pylori stricture-fixed with suturing. D. Endoscopic fistulotomy for perianal fistula using free hand technique using needle knife. E. Post fistulotomy, F. Endoscopic seton placement: Guidewire placed through external opening, G. Guidewire grabbed by forceps, H. Endoscopic seton placed, I. Endoscopic ultrasound (EUS) guided abscess drainage: Needle puncture, J. Pigtail placed under EUS guidance, K. Echoendoscope and pigtail stent seen after EUS guided drainage on fluoroscopy (adapted from Pal P, Reddy DN. Gastroenterol Rep (Oxf). 2024 Jul 25;12).

3. Endoscopic balloon dilation (EBD)

3.1. Outcomes of EBD
EBD is the most commonly used technique for treating IBD-related strictures, with high technical (74–100%) and clinical success rates, and a low complication rate (0–10.6%).⁵ However, about 50% of patients experience symptom recurrence, and up to two-thirds may need repeat dilation or surgery over time. A meta-analysis reported technical and clinical success rates of 94.9% and 82.3% in small bowel CD strictures, with 48.3% recurrence and 66% requiring re-intervention.⁶ Outcomes for ileocolonic strictures were similarly favorable. Gastro-duodenal strictures had higher recurrence (70.5%) despite excellent initial success and low complication rates.

3.2. Comparison of EBD with other techniques

3.2.1. EBD versus surgery:
EBD offers an effective, less invasive alternative to surgery for short CD strictures, with the potential to delay surgery by up to 6.5 years. However, recurrence is common—
45% require surgery within 2 years, and only 15% remain surgery-free at 5 years.¹ A recent prospective study showed similar clinical outcomes between EBD and surgery, though EBD had a higher rate of re-intervention at 1 year follow up for CD strictures (<5 cm, ≤ 3 in number).⁷

3.3. Predictors of EBD efficacy:
Several factors including short stricture length (≤3-5 cm), anastomotic & colonic location, graded dilation (≥15 mm), and anti-TNF/thiopurine use (Ref ), predict positive outcomes
with EBD. Poor outcomes are linked to long length (> 5-6 cm), proximal, inflamed, or de-novo strictures, high BMI, and pre-stenotic dilation. Anastomotic strictures respond better to EBD than de-novo ones. Risk models like BACARDI can guide therapy selection and predict long-term outcomes.³ In ileo-colonic anastomotic (ICA) strictures, the 5-year surgery-free survival after EBD can be predicted based on a nomogram (developed based on a retrospective study) which includes disease duration, duration from time of surgery, pre-stenotic dilation, and presence of symptoms.⁸

4. Endoscopic stricturotomy (ES)

4.1. Patient selection for ES:
ES is best suited for short (≤2-3 cm), fibrotic, or mixed strictures—either as a first-line option or in refractory cases. Based on individual expertise, ES can be performed in all locations within the GI tract, but ideal locations include the ileocecal region, ano-rectal, and pylorus.⁹ Risk of perforation from ES is low (<1%), however in certain locations it can be challenging to manage this. So, caution should be used while performing ES in duodenum, esophagus, and small bowel.¹⁰ Complications after duodenal and esophageal ES can be
life threatening.⁹ ES yields better outcomes in anastomotic strictures than de-novo strictures, likely due to their surgical origin.

4.2. Method of ES
The procedure involves radial followed by circumferential incisions into the stricture. This can be combined with through-the-scope (TTS) clip placement (stricturoplasty) to prevent re-stenosis and bleeding or without TTS clip placement. There is no data of one being superior to the other. Tools include a needle knife or an insulated-tip knife (IT knife), with depth guided by knife length, and cuts not to extend beyond muscularis mucosa. The Endocut-I setting (effect-3, cut duration-1, cut interval 3) is commonly used to minimize bleeding risk.¹¹ A distal cap can improve control, though it may limit visibility. ES is easiest when using a therapeutic gastroscope or colonoscope; small bowel strictures may require balloon-assisted enteroscopy with use of anti-peristaltic agent but pose greater technical difficulty and risk.

4.3. Outcomes of ES:
ES shows high technical success (92–100%) and variable clinical success (42–100%), depending on the indication. While repeat procedures are sometimes needed (8–62%), the surgery rate is generally lower than with EBD (9–22%). ES carries a lower risk of perforation (~1%) but a higher risk of bleeding requiring transfusion (6–10%) compared to EBD.^12-14

4.4. Comparison of ES with other techniques

4.4.1 ES versus surgery:
A study comparing ES with ileocolonic resection (ICR) for distal ileal strictures found similar surgery-free survival (15–19%) but fewer post-procedure complications with ES. Follow-up duration was limited (~1.5 years), and longer-term data are needed.¹⁴

4.4.2 ES versus EBD:
Comparative studies show ES outperforms EBD in long-term outcomes for anastomotic strictures, with fewer emergency visits and surgeries. However, ES is more prone to bleeding, while EBD has a higher perforation risk. Both are safe and effective, with ES offering better durability in selected patients.¹⁵

5. Endoscopic Stenting

5.1. Indications and types
Stenting was among the earliest endoscopic methods for IBD strictures. Use of stents in IBD patients should be used cautiously, as long-term safety and efficacy data is lacking. Over time, various types have been used, including fully covered (FCSEMS), partially covered (PCSEMS), uncovered SEMS, lumen-apposing metal stents (LAMS), and biodegradable stents. Stents may be used in refractory cases after failed balloon dilation or stricturotomy. Long strictures (>4–5 cm) are ideal for FCSEMS, while PCSEMS (for very short duration) may be better for shorter ones due to lower migration. LAMS are suited for short, accessible anastomotic strictures, although they are not FDA approved for luminal use. Biodegradable stents offer temporary support but are not yet standard for routine use.

5.2. Technical tips for endoscopic stenting in IBD
Choose a stent at least 1.5 cm longer than the stricture on both ends to account for shortening. Stricture length is assessed using contrast after guidewire placement. Fixation may involve clips or sutures. LAMS are deployed similarly to pancreatic collections, without electric energy. Data on stenting duration is limited, but shortest possible interval should be chosen (7-10 days).¹⁶

5.3. Results of endoscopic stenting
Meta-analysis shows technical success of 93% and clinical success of 61% for CD strictures. Common issues include stent migration (up to 44%). pain (18%), and perforation (3%). Long-term data remain limited, with follow-up durations varying widely (3–69 months).¹⁷

5.4. Comparison of stenting with other techniques:

5.4.1 Stenting versus EBD:
In the ProtDilat RCT, stenting had higher re-intervention rates at 1 year (49%) than EBD (20%), suggesting EBD is more effective for primary therapy. However, stents may still be valuable for long, refractory strictures.¹⁸ Ongoing trials like ENDOCIR (NCT04330846) will further clarify stenting’s role compared to surgery.

6. Endoscopic management of fistula and abscesses

Understanding fistula type (based on etiology, location, depth, and complexity) is key before intervention. Two-thirds are external, with perianal fistulas being most common. Management involves: (1) drainage of abscess, (2) fistulotomy, (3) filling the tract, and (4) closure of internal opening. Any associated stricture should be treated first.

6.1. Endoscopic drainage

6.1.1. Incision and drainage:
Needle knife drainage and fistulotomy are effective for short, superficial perianal fistulas, and pouch body fistulas. Longer tracts may require partial incision avoiding anal sphincters (Figure 3, D-E).¹⁹

6.1.2. Endoscopic seton placement
Feasible in simple perianal fistulas using guidewire technique (Figure 3, F-H).²⁰ Complex fistulas may require fistuloscopy with ultra-thin scopes.²¹

6.1.3 EUS guided drainage:
Used for pelvic/intra-abdominal abscesses inaccessible by radiology. Pigtail drainage can be performed with or without EUS (Figure 3, I-K).¹⁹

6.2. Endoscopic fistulotomy
Suitable for short (<2-3cm), superficial fistulas including perianal, ileocecal, and pouch-related types. One series showed ~90% resolution.²² Clip placement post-fistulotomy can prevent re-approximation. Avoid in deep, complex, or high-risk locations near urogenital structures.

6.3. Injection of filling materials

6.3.1. Glue
Glue injection can be done endoscopically around the internal opening of the fistula. The data for glue injections is conflicting. There are some benefits in simple fistula with up to 45% healing which is better with combined biologics and immunomodulators (63%).²³

6.3.2. Anal fistula plug (AFP)
Shows 38–83% success in simple fistulas.²⁴ Long-term benefit over seton alone is unclear.

6.3.3. Stem cells
Injection of adipose tissue-derived allogeneic stem cells (120 million cells) effectively induced clinical and radiologic fistula remission at 24 weeks, with remission rates of 51% versus 36% with placebo. This effect was sustained at 52 weeks in refractory complex perianal fistulas.²⁵

6.3.4. Sclerosing agents
Injection of 10 ml of 50% dextrose plus doxycycline (3 sessions) into a chronic non-healing sinus in the rectal stump post J pouch induced fibrosis and promoted healing.²⁶

6.4. Endoscopic closure

6.4.1. Endoscopic clipping
OTSC outperforms TTS clips for IBD surgery-related anastomotic leaks, with higher efficacy in leaks and perforations but not ideal for primary CD fistulas or bowel-to-hollow organ fistulas, due to suboptimal success rates and potential worsening respectively.

6.4.2 Endoscopic suturing
Limited data in IBD. May help close large defects or secure SEMS but not suitable for bowel-to-hollow organ fistulas (e.g., rectovaginal) or proximal bowel fistulas due to technical challenges.

6.4.3. Endoscopic stenting
Used in select cases, but issues like stent migration and limited long-term data restrict broader use. 

7. Colitis associated neoplasia

Historically, any dysplasia in ulcerative colitis (UC) warranted colectomy. However, based on new SCENIC consensus guidelines, visible/polypoidal lesions, including low-grade dysplasia (HGD), can now be managed with endoscopic resection and close surveillance (Figure 4). Outcomes of endoscopic resection are comparable to surgery, though vigilant follow-up is critical for detecting metachronous lesions.

Figure 4. Endoscopic management of ulcerative colitis associated neoplasia (UCAN). SMI; submucosal invasion. LST: laterally spreading tumor, EMR: endoscopic mucosal resection, ESD: endoscopic submucosal dissection, LGD: low grade dysplasia, HGD: high grade dysplasia (adapted from Pal P, Reddy DN. Gastroenterol Rep (Oxf). 2024 Jul 25;12).

7.1. Endoscopic mucosal resection (EMR)
EMR is safe for flat or polypoid lesions. Underwater EMR (UEMR) is especially effective in fibrotic, scarred areas, offering better resection in UC-associated neoplasia (UCAN) due to "floating" and "heat-sink" effects.²⁷

7.2. Endoscopic submucosal dissection (ESD)
ESD provides high en-bloc (83%) and R0 (67%) resection rates. It is ideal for large or non-polypoidal UCAN but technically challenging due to submucosal fibrosis (SMF) (in nearly 40%). New techniques like water-pressure-assisted ESD and multi-traction clips help overcome these barriers. Despite good outcomes, 70% may develop metachronous lesions (21% endoscopically invisible) warranting intensive surveillance and requiring further treatment.²⁸

7.3. Choice of Endoscopic Resection Technique for UCANL
ESD is preferred for lesions ≥11 mm or with fibrosis; EMR suits small (≤10 mm), non-fibrotic lesions. While ESD offers better R0 rates, it carries higher risk of perforation (~10%). Both techniques reduce colectomy need.²⁹ Sporadic adenomas in non-colitic segments carry lower progression risk and can be managed with standard polypectomy or EMR.

7.4. Alternative Modalities to EMR or ESD:
Hybrid ESD/EMR or use of full-thickness resection device (FTRD) is useful for non-lifting or fibrotic leisons. FTRD has been successfully applied in UC patients with fibrotic adenomas, offering another option when standard resection is difficult.³⁰

8. Role of IIBD in postoperative pouch complications in UC

Endoscopic therapy is key in managing pouch-related issues after IPAA surgery in UC. Common complications include strictures, leaks, fistulas, sinuses, floppy pouch syndrome, and pouch neoplasia (Figure 5).

Figure 5. Algorithm for endoscopic management of pouch related complications. LGD: low grade dysplasia, HGD: high grade dysplasia, ESD: endoscopic submucosal dissection, ES: endoscopic stricturotomy, EBD: Endoscopic balloon dilation, OTSC: over the scope clip, EVT: endoscopic vacuum therapy, EMR: Endoscopic mucosal resection. (adapted from Pal P, Reddy DN. Gastroenterol Rep (Oxf). 2024 Jul 25;12).

8.1. Pouch strictures:
Pouch inlet and outlet strictures are treated with EBD or ES. EBD has high technical (98%) and clinical (95%) success with low complication rates. ES may have higher bleedingrisk, while EBD has a small risk of perforation. Long-term success is good, especially in fibrotic strictures. Surgery (stricturoplasty or pouch excision) is considered for refractory or long (>5 cm) strictures.¹⁵

8.2. Pouch leaks:
Leaks without abscess formation, especially at the tip of the J-pouch, and chronic in nature, can be closed with over-the-scope clips (OTSCs), though half may need repeat therapy or surgery. Endoscopic vacuum therapy (EVT) is effective for anastomotic leaks, with faster healing and reduced need for surgery compared to conventional treatment.³¹

8.3. Pouch fistula:
Endoscopic fistulotomy works well for short, simple fistulas like pouch-to-pouch or perianal types, with ~90% success. Clipping may help in select cases. Compared to redo-surgery, endoscopic management shows better healing and fewer complications.³²

8.4. Pouch sinus:
Endoscopic sinusotomy is effective for small anastomotic sinuses, with lower morbidity than surgery. EVT helps prevent chronic sinus formation. For large, deep, or symptomatic sinuses, surgery may still be needed. Healing is influenced by factors like disease type, body mass index, and timing between sessions.³³ 

8.5. Pouch neoplasia
Dysplasia and cancers can develop post-IPAA. Risk factors include PSC, chronic pouchitis, prior dysplasia, and type C mucosa. High-risk patients need annual pouchoscopy; low risk every 3 years. Visible low-grade dysplasia (LGD) can be endoscopically resected (EMR/ESD), followed by close surveillance. Multifocal, flat, or high-grade dysplasia may require surgery.³⁴

9. Endoscopic retrieval of retained capsule endoscope

Capsule retention in IBD can be managed using double-balloon enteroscopy (DBE) or motorized spiral enteroscopy, often with balloon dilation of small bowel strictures. DBE shows high success rates (80–92%) for capsule retrieval.³⁵

10. Bleeding control:

Focal bleeding from visible vessels in UC or CD can be effectively managed using hemoclips during endoscopy.³⁶

11. Conclusion

Managing IBD complications via endoscopy is complex due to inflammation, fibrosis, altered anatomy, and immunosuppression. IIBD offers a minimally invasive alternative that can delay or prevent surgery, manage post-op issues, and serve as a bridge between medical and surgical therapy. The field is expanding and demands multidimensional skillsets (Figure 6). With proper training and multidisciplinary support, IIBD can be pivotal in modern IBD management. Robust long-term trials are needed to define its place in treatment algorithms.

Figure 6. The multi-dimensional skill set of an interventional IBD endoscopist: major skills, minor skills and additional skills. OTSC: over the scope clip, EMR: Endoscopic mucosal resection, EFTR: endoscopic full thickness resection, EUS: Endoscopic ultrasound, ERCP: endoscopic retrograde cholangiopancreatography, PSC: primary sclerosing cholangitis, NBI: narrow band imaging, CLE: confocal laser endomicroscopy, TPUS: transperineal ultrasound.

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