Enteroscopy in small bowel Crohn's disease: A review

Crohn's disease (CD) is a chronic inflammatory condition of the gastrointestinal tract resulting in inflammation, stricturing and fistulae secondary to transmural inflammation. Diagnosis relies on clinical history, abnormal laboratory parameters, characteristic radiologic and endoscopic changes within the gastrointestinal tract and most importantly a supportive histology. The article is intended mainly for the general gastroenterologist and for other interested physicians. Management of small bowel CD has been suboptimal and limited due to the inaccessibility of the small bowel. Enteroscopy has had a significant renaissance recently, thereby extending the reach of the endoscopist, aiding diagnosis and enabling therapeutic interventions in the small bowel. Radiologic imaging is used as the first line modality to visualise the small bowel. If the clinical suspicion is high, wireless capsule endoscopy (WCE) is used to rule out superficial and early disease, despite the above investigations being normal. This is followed by push enteroscopy or device assisted enteroscopy (DAE) as is appropriate. This approach has been found to be the most cost effective and least invasive. DAE includes balloon-assisted enteroscopy, [double balloon enteroscopy (DBE), single balloon enteroscopy (SBE) and more recently spiral enteroscopy (SE)]. This review is not going to cover the various other indications of enteroscopy, radiological small bowel investigations nor WCE and limited only to enteroscopy in small bowel Crohn's. These excluded topics already have comprehensive reviews. Evidence available from randomized controlled trials comparing the various modalities is limited and at best regarded as Grade C or D (based on expert opinion). The evidence suggests that all three DAE modalities have comparable insertion depths, diagnostic and therapeutic efficacies and complication rates, though most favour DBE due to higher rates of total enteroscopy. SE is quicker than DBE, but lower complete enteroscopy rates. SBE has quicker procedural times and is evolving but the least available DAE today. Larger prospective randomised controlled trial's in the future could help us understand some unanswered areas including the role of BAE in small bowel screening and comparative studies between the main types of enteroscopy in small bowel CD.