What Is Enteroscopy? Procedure Types and What to Expect

Enteroscopy is a specialized endoscopic procedure designed to reach the small intestine, the longest and least accessible segment of the digestive tract. Standard upper endoscopy can visualize the esophagus, stomach, and the first part of the small bowel, while colonoscopy covers the colon and the very end of the small bowel. That leaves several meters of intestine in between that neither procedure can reach. Enteroscopy fills that gap, and over the past two decades the technology for doing so has become substantially more capable, turning what was once a purely diagnostic tool into a platform for treating bleeding, stretching open strictures, and removing polyps without surgery.

Why the Small Bowel Is So Hard to Examine

The small intestine averages roughly six meters in length in a living adult. It is coiled, loopy, and suspended by a flexible membrane called the mesentery, which means pushing an endoscope forward often just stretches the intestine rather than advancing through it. For decades, this anatomy left the small bowel as something of a blind spot in gastroenterology. A standard upper endoscope reaches only the duodenum, and a colonoscope can back into the terminal ileum but goes no further. Capsule endoscopy, the swallowable camera pill, can take pictures along the entire route but cannot take biopsies or deliver treatment. Enteroscopy exists to solve both problems: it can reach deep into the small bowel and do something about what it finds.

Push Enteroscopy

The simplest form of enteroscopy is called push enteroscopy. It uses a longer, stiffer version of a standard upper endoscope, sometimes with a stiffening overtube slipped over the shaft to prevent the scope from looping in the stomach. The endoscopist feeds the instrument through the mouth, past the stomach, and as far into the small bowel as possible. A push enteroscope can typically visualize roughly half the small bowel mucosa, and the technique produces its best results in patients being screened for polyposis syndromes or investigated for hidden gastrointestinal bleeding.¹ In practice, mean insertion depth beyond the pylorus is around 120 centimeters, with a diagnosis made in about 40% of procedures.²

Push enteroscopy is quick and does not require highly specialized equipment beyond what many endoscopy units already have. Its main limitation is reach: once the instrument begins to loop, further pushing stretches the bowel instead of advancing, and the endoscopist has to stop. For lesions suspected to be deeper in the jejunum or ileum, balloon-assisted techniques have largely taken over.

Balloon-Assisted Enteroscopy

The breakthrough that made deep small-bowel endoscopy routine was the addition of inflatable balloons to an overtube system. Double-balloon enteroscopy (DBE), introduced in the early 2000s, uses two balloons: one at the tip of the endoscope and one at the tip of the overtube. By alternately inflating and deflating these balloons, the endoscopist pleats the intestine onto the overtube much like bunching a curtain onto its rod, preventing the loops that defeat push enteroscopy. Single-balloon enteroscopy (SBE) uses one balloon on the overtube and relies on tip deflection of the scope itself to anchor the bowel during advancement.

Early data on DBE showed the technique could visualize far more of the small bowel than push enteroscopy. In one study, the oral route allowed visualization of an average of 240 centimeters of the small bowel, and the anal route covered about 140 centimeters. The diagnostic yield in that cohort was 80%, with the most common finding being angiodysplasia, followed by ulcers and erosions, and then polyps or tumors.³ A multicenter randomized trial comparing DBE with SBE found similar insertion depths: roughly 250 centimeters orally and about 110 to 120 centimeters anally for both techniques.⁴ Complete visualization of the entire small bowel in a single session remains uncommon, achieved in under a fifth of cases even with DBE.

Whether SBE and DBE perform differently has been a recurring question. A meta-analysis pooling data from multiple comparative studies found no significant difference between the two in diagnostic yield, ability to deliver therapy, or complication rates.⁵ One single-center retrospective analysis did find that SBE had a higher diagnostic rate than DBE when performed from the anal route, though the two were equivalent by the oral route.⁶ In practical terms, the choice between SBE and DBE often comes down to institutional experience and equipment availability rather than a clear performance advantage of one over the other.

Spiral Enteroscopy and Motorized Systems

A third approach uses a spiral-shaped overtube that threads over the endoscope. By rotating the overtube, the endoscopist pleats the intestine forward along helical grooves. Traditional manual spiral enteroscopy was somewhat cumbersome, but a motorized version has been developed that automates the rotation, with the goal of shortening procedure times and potentially making total enteroscopy in a single session more achievable.⁷ Early clinical experience with the motorized system has been encouraging, though the technology is still newer and less widely available than balloon-assisted methods.

When and Why Enteroscopy Is Performed

The most common reason to perform enteroscopy is obscure gastrointestinal bleeding, meaning bleeding whose source has not been identified by standard upper endoscopy or colonoscopy. In one tertiary-center study of 81 patients with obscure bleeding who underwent SBE, the diagnostic yield was about 73%. Bleeding sources were more commonly found in the proximal small intestine (the far end of the duodenum and the jejunum) than in the ileum. Angiodysplasia, clusters of abnormal blood vessels in the bowel wall, accounted for nearly a third of diagnoses, followed by solitary ulcers and tumors.⁸ Among patients where a bleeding source was identified, close to half underwent endoscopic treatment during the same procedure, including injection therapy, heat probe cauterization, and clip placement.

Enteroscopy also plays an important role for patients with Crohn’s disease who develop small-bowel strictures. These narrowings can cause obstructive symptoms like cramping, nausea, and vomiting. Balloon dilation performed through an enteroscope can stretch open these strictures and potentially avoid surgery. A meta-analysis of studies on balloon-assisted dilation for Crohn’s strictures found that technical success rates were about 95%, with short-term symptom relief in roughly 82% of patients. About a quarter eventually needed surgery during follow-up.⁹ A prospective single-center study with longer follow-up tracked 150 patients through 235 dilation procedures and found cumulative surgery-free rates of roughly 87% at one year and 77% at five years. Stricture shape mattered: web-like strictures had the best outcomes, while spindle-shaped strictures were much more likely to require eventual surgery.¹⁰

Other therapeutic applications include polypectomy (removing polyps found during the exam), retrieval of foreign bodies, and treatment of angiodysplastic lesions with cautery or clipping.¹¹ In a small number of early cases, DBE was also used to confirm findings from capsule endoscopy and treat bleeding sources that the capsule had identified but could not address.¹²

How Capsule Endoscopy and Enteroscopy Work Together

Capsule endoscopy and device-assisted enteroscopy are not competing technologies. In current practice, the capsule often comes first. The patient swallows the camera pill, which takes thousands of images as it transits the small bowel over several hours. A gastroenterologist reviews those images looking for lesions. If the capsule finds something that needs biopsy or treatment, enteroscopy follows. The European Society of Gastrointestinal Endoscopy recommends device-assisted enteroscopy to confirm and treat lesions identified by capsule endoscopy.¹³ The capsule findings also help the endoscopist decide whether to approach from the mouth (oral route, better for proximal lesions) or from below (anal route, better for ileal lesions), which saves time and reduces the likelihood of needing a combined approach.

When compared head-to-head against imaging techniques like CT enterography, enteroscopy consistently shows higher diagnostic accuracy for small-bowel diseases. One study comparing DBE with multidetector CT enterography found overall diagnostic yields of about 83% versus 34%, respectively.¹⁴ Another study focused on small-bowel Crohn’s disease found DBE significantly outperformed dual-energy CT enterography in detecting stenosis and ulcers.¹⁵ The trade-off is that enteroscopy is invasive, requires sedation, and takes longer. Cross-sectional imaging is faster and noninvasive, so it remains useful as an initial screen or for mapping disease extent before an enteroscopy is planned.

Risks and Complications

Enteroscopy is generally safe, but it is more invasive than standard endoscopy and carries a small set of procedure-specific risks. The most serious complication is intestinal perforation, where the scope creates a hole in the bowel wall. A large Japanese national database study of more than 29,000 diagnostic balloon-assisted enteroscopy procedures found a perforation rate of about 0.1%. Patients with inflammatory bowel disease who were on steroids had a substantially higher risk.¹⁶ A nine-year multicenter study of nearly 2,900 SBE procedures found a major complication rate of about 0.4%, with all major complications being perforations. Most perforations occurred in the ileum, and prior abdominal surgery was a significant risk factor.¹⁷

Acute pancreatitis is another recognized complication, particularly with oral DBE. The incidence has been reported at around 0.3% for diagnostic procedures. The mechanism is not entirely clear but is thought to involve mechanical strain on the pancreas or the area around the bile duct papilla during the push-and-pull maneuvers of the overtube.¹⁸ Elevated pancreatic enzyme levels after DBE are actually quite common even without true pancreatitis, so clinicians have to distinguish between a lab abnormality that resolves on its own and genuine inflammation.

Therapeutic enteroscopy carries somewhat higher risk than diagnostic procedures, as you would expect when the endoscopist is cauterizing a vessel, dilating a stricture, or cutting away a polyp. For Crohn’s stricture dilation specifically, one meta-analysis reported major complications in about 5% of patients.¹⁹ The long-term single-center study mentioned earlier reported a lower per-procedure complication rate of under 2% for balloon dilation, likely reflecting growing institutional expertise and patient selection.²⁰

Enteroscopy in Children

Children present additional challenges for enteroscopy. Smaller body size means shorter bowel length but also narrower lumens, and sedation considerations differ. Despite limited data compared to adults, the procedure has been used successfully in pediatric patients. A study of 48 children undergoing DBE reported a diagnostic yield of 65%, with only one complication (post-polypectomy bleeding) and no perforations or pancreatitis.²¹ A larger series of 257 pediatric cases found the overall complication rate was about 5%, though it was higher (around 10%) in children under 10 years old. No severe complications related to scope insertion or sedation occurred.²²

A review of the pediatric literature concluded that device-assisted enteroscopy, used alongside MR enterography and capsule endoscopy, allows identification and treatment of many small-bowel diseases in children with a low risk of complications.²³ The same capsule-first, enteroscopy-second workflow used in adults applies to older children, though very young patients may not be able to swallow the capsule and sometimes need it placed endoscopically.

The Learning Curve

Enteroscopy is technically demanding, and there is a real learning curve. One analysis of 282 DBE procedures estimated that an endoscopist needs roughly 30 to 35 supervised retrograde (anal-approach) cases to achieve consistent technical success above 75%.²⁴ A multi-center U.S. study found that procedure times dropped significantly after the first 10 oral DBE cases and that fluoroscopy time also decreased, suggesting more efficient scope handling with experience. The retrograde approach, however, showed no such improvement over the same case volume, indicating it is the harder technique to master.²⁵

This training demand is one reason enteroscopy tends to be concentrated at academic medical centers and specialized referral hospitals. Community gastroenterologists may not perform enough cases to maintain proficiency. If your doctor recommends enteroscopy, it is worth asking how many procedures the endoscopist performs annually, just as you would for any technically complex procedure.

What to Expect as a Patient

Preparation depends on the route. For an oral-approach enteroscopy, you fast overnight, much as you would for a standard upper endoscopy. For a retrograde approach or a combined procedure, you need a full bowel preparation similar to what is done before a colonoscopy. The procedure itself is performed under deep sedation or general anesthesia in most centers, because the repeated push-and-pull maneuvers last considerably longer than a routine scope exam. Procedure times for balloon-assisted enteroscopy range from about 40 minutes to well over an hour, depending on the depth of insertion, whether therapy is performed, and whether both oral and anal approaches are needed.

After the procedure, patients typically stay in a recovery area for an hour or two while the sedation wears off. Most go home the same day. Mild bloating, a sore throat (if the oral route was used), and some abdominal discomfort are common and usually resolve within a day. More severe symptoms like sharp abdominal pain, fever, or significant bleeding should prompt immediate medical attention, as they can signal perforation or other complications.

Artificial Intelligence in Enteroscopy

One of the newer frontiers in the field is applying artificial intelligence to help endoscopists spot abnormalities during enteroscopy in real time. The small bowel generates a huge volume of endoscopic images, and subtle lesions can be easy to miss, especially for less experienced operators. Research groups have developed deep-learning algorithms trained on thousands of enteroscopy frames. One AI model designed for device-assisted enteroscopy images achieved a sensitivity and specificity of 97% for detecting protruding lesions like polyps and tumors.²⁶

A system called ENDOANGEL-DBE went a step further, not only detecting abnormalities but classifying them. In a video-based test set, the system outperformed human endoscopists, achieving 85% accuracy compared to an average of 77% among the clinicians.²⁷ Similar AI work has been done for capsule endoscopy, where an algorithm detected protruding lesions with about 97% accuracy and could process roughly 355 frames per second, fast enough to work in real time as the capsule transmits images.²⁸ These tools are still mostly in development and validation stages, but the trajectory suggests AI-assisted enteroscopy could meaningfully reduce missed lesions, particularly at centers where the procedure volume is low and operators are less experienced.

Stricture Dilation and the Question of Surgery

For patients with Crohn’s disease, the relationship between enteroscopic dilation and surgery deserves a closer look, because it is one of the most impactful therapeutic applications of the technology. The core appeal is straightforward: stretching a stricture with a balloon threaded through an enteroscope is far less disruptive than surgically removing a segment of bowel. Every surgical resection in Crohn’s disease shortens the small intestine, and repeated surgeries can eventually cause short-bowel syndrome, a condition where there is not enough intestinal surface area to absorb adequate nutrition.

The evidence shows that enteroscopic dilation works well in the short term, with symptom relief in the large majority of patients and very high technical success rates. The longer-term picture is more nuanced. About half of patients experience symptom recurrence during follow-up, and roughly 40% undergo repeat dilation.²⁹ That is not a failure of the technique so much as a reflection of the disease: Crohn’s inflammation is chronic and tends to cause recurrent narrowing. Repeated dilations can buy years of surgery-free time. Patients who also receive biologic therapy (drugs targeting specific immune pathways) appear to do better than those on conventional therapy alone, which makes sense given that controlling the underlying inflammation slows re-stricturing.³⁰ Earlier work on a smaller group of patients with Crohn’s strictures also showed dramatic improvements in symptom scores after DBE-assisted dilation, with the authors noting it should be considered a useful alternative to surgery in selected patients.³¹

Not every stricture is a good candidate for dilation. Short, web-like strictures respond best. Longer, spindle-shaped narrowings and those with active ulceration carry higher rates of eventual surgical referral. The decision about whether to dilate or operate is typically made collaboratively between a gastroenterologist and a surgeon, taking into account stricture morphology, disease activity, prior surgical history, and the patient’s nutritional status.