Key points

Introduction

The small bowel has remained the final frontier for endoscopic exploration of the luminal gastrointestinal (GI) tract. Over the last decade, deep small bowel enteroscopy has dramatically improved and has now moved into the realm of routine gastroenterology practice. This progress had led to a significant improvement in the diagnostic capabilities and treatment strategies available to the patient. Although enteroscopy is generally a safe procedure, the rate of adverse events is higher than conventional upper or lower endoscopy. Knowledge of potential endoscopic adverse events, their expected frequency, and the risk factors associated with their occurrence may help to minimize the incidence of adverse events.

Introduction

The small bowel has remained the final frontier for endoscopic exploration of the luminal gastrointestinal (GI) tract. Over the last decade, deep small bowel enteroscopy has dramatically improved and has now moved into the realm of routine gastroenterology practice. This progress had led to a significant improvement in the diagnostic capabilities and treatment strategies available to the patient. Although enteroscopy is generally a safe procedure, the rate of adverse events is higher than conventional upper or lower endoscopy. Knowledge of potential endoscopic adverse events, their expected frequency, and the risk factors associated with their occurrence may help to minimize the incidence of adverse events.

Types of deep small bowel enteroscopy procedures

There are 3 deep small bowel enteroscopy platforms referred to as overtube-assisted or device-assisted deep small bowel enteroscopy. These platforms include double-balloon enteroscopy (DBE), single-balloon enteroscopy (SBE), and spiral enteroscopy. All 3 systems are comparable regarding insertion depths, diagnostic and therapeutic efficacies, and adverse event rates. The choice of enteroscopy technique depends on availability, personal experience, and clinical implication. All enteroscopy platforms can be used in antegrade (per oral) or retrograde (per rectum) routes. The depth of insertion by antegrade route is about 200 to 250 cm beyond the ligament of Treitz. Enteroscopy via the antegrade route has been reported to have a higher diagnostic and therapeutic yield as well as higher success rate and faster learning curve than the retrograde route. In some cases, the entire small bowel can be evaluated using a combination of antegrade and retrograde approaches (also known as total enteroscopy), but this cannot be reliably and routinely accomplished in all patients.

Both DBE and SBE (also known as balloon-assisted enteroscopy) consist of a 200-cm working length enteroscope and a 140-cm to 145-cm soft overtube. Technique for advancement uses a push and pull method, with inflation and deflation of the balloon(s) and telescoping of the small intestine onto the overtube. This telescoping allows the endoscope to advance a longer distance compared with conventional push enteroscopy with minimal looping. Every 5 cm of overtube advancement resembles 40 cm of small bowel visualized. DBE is the most frequently enteroscopy platform used, because it was introduced first in 2001 and has relatively high rates of total enteroscopy (>40%). The system uses 2 types of endoscopes (regular or therapeutic scope). SBE was introduced in 2007. It seems that total enteroscopy is more easily performed and achieved with DBE than with SBE; however, diagnostic yield and adverse event rate are comparable.

Spiral enteroscopy is the most recently introduced technique, in which an endoscope is fitted with a rotating overtube that has a soft spiral fin at the tip. Spiral enteroscopy involves the rotation of a spiral-tipped overtube device, thus, pleating the small bowel to allow deep small bowel evaluation and interventions. Retrograde spiral enteroscopy is usually needed to achieve total enteroscopy, if at all. Spiral enteroscopy has been reported to be as safe as DBE, with similar diagnostic and therapeutic yield, but it involves shorter examination times. It also allows the enteroscope to be removed and reintroduced while holding the position deep in the small bowel using the spiral overtube. This technique can be particularly useful when multiple polypectomies are required in patients with intestinal polyposis syndromes such as Peutz-Jeghers syndrome.

Indications for enteroscopy

The indications for enteroscopy include diagnosis and therapeutic interventions for small intestinal diseases and have continued to expand. Because the rate of adverse events related to enteroscopy is higher than conventional upper or lower endoscopy, a well-established indication is strongly endorsed. The most common indication for enteroscopy is the evaluation and diagnosis of small bowel lesions as a cause of iron deficiency anemia, GI bleeding, and suspected inflammatory bowel disease or mass. Enteroscopy-guided therapy in patients with obscure GI bleeding is cost effective and has been shown to reduce the rate of overt bleeding and the need for iron supplementation, blood transfusions, and additional invasive procedures. Additional indications include retrieving retained video capsules and biopsy/marking of lesions for further laparoscopic management. Enteroscopy can also be used in patients with surgically altered upper GI anatomy, such as Roux-en-Y gastric bypass, to examine the excluded segment of the small bowel or excluded gastric remnant and also as a platform for endoscopic retrograde cholangiopancreatography (ERCP). Recently, deep small bowel enteroscopy endoscopes have been shown to be a useful tool in patients with difficult colonoscopy and failed colonoscopy. Reported indications for deep small bowel enteroscopy along with diagnostic and therapeutic maneuvers are summarized in Box 1 .

The need for routine use of capsule endoscopy or other small bowel imaging study before enteroscopy remains a controversial issue. Prescreening patients with capsule endoscopy improves the diagnostic and therapeutic yield of enteroscopy. Preferential use of capsule endoscopy followed by enteroscopy for obscure GI bleeding has been suggested as a diagnostic strategy. The use of capsule endoscopy before enteroscopy has also been shown to be cost effective for diagnosis and possible therapeutic interventions in small bowel Crohn disease. Furthermore, capsule endoscopy is safe, and adverse events are uncommon. On the other hand, capsule endoscopy and other small bowel imaging studies are frequently nondiagnostic and do not provide any therapeutic capabilities. Therefore, capsule endoscopy before enteroscopy should not be performed routinely, but on a case-by-case basis.

Contraindications

Enteroscopy can be safely performed in most patients. DBE has a high and increasing diagnostic yield with age, leading to a high positive impact on management in elderly patients. DBE has also been reported as a safe tool in children. Furthermore, DBE has also been reported to be equally safe and effective when performed in a community setting compared with a tertiary referral center with a comparable yield, efficacy, and adverse event rate. In addition, the diagnostic and therapeutic yields are not influenced by the timing of enteroscopy (morning vs afternoon).

Patients with suspected or impending GI perforation should not undergo enteroscopy. If deep enteroscopy is required with a true latex allergy, SBE or spiral enteroscopy should be considered, because the DBE balloons contain latex.

Overtube-assisted enteroscopy is relatively contraindicated in patients with esophageal stricture or varices. Spiral enteroscopy in particular should be avoided in these patients because the spiral overtube has a larger diameter compared with DBE and SBE. Moreover, the overtubes used with DBE and SBE do not require mechanical rotation and may be a safer choice. However, in the absence of robust comparative data, there are no specific guidelines as to which enteroscopy platform to use in particular clinical situations, and decisions must be individualized to each patient and condition.

General rules of thumb

There are various technical aspects in performing deep small bowel enteroscopy with the different platforms, but some general rules of thumb apply:

• •
  

  Enteroscopy performed in appropriately selected individuals is a highly useful and safe clinical tool. Select patients carefully to maximize procedural efficacy, safety and minimize its adverse events.

  
  
• •
  

  Review clinical data, including medications, carefully and identify high-risk patients for proper plans on type of sedation, endoscopic option, interventions, and so forth.

  
  
• •
  

  A well-defined indication is required before performing enteroscopy. Review of all previous studies, including radiologic small bowel imaging and capsule endoscopy findings, is imperative for estimating the approximate location of a lesion and planning an antegrade versus retrograde approach. Review of previous surgeries to understand the patient’s altered GI altered anatomy is also essential for preprocedural considerations.

  
  
• •
  

  Carefully select the anticoagulation and antiplatelet management options. If a decision is made to perform endoscopy in patients receiving antithrombotic therapy, the need to stop or reverse these agents should be individualized. Performing the procedure while continuing these agents may be associated with higher yield in bleeding cases. No prospective data are available to determine which international normalized ratio is necessary for endoscopic therapy to be safe and effective. Several new anticoagulants and antiplatelet agents were recently approved, and their use as it relates to endoscopy was summarized in a recent review. Endoscopists should be familiar with these medications to optimize outcomes and seek input of relevant consultants (eg, cardiology, hematology, and neurology) before discontinuing any antithrombotic agents.

  
  
• •
  

  Careful enteroscope insertion, examination, and intervention are essential to avoid adverse events. The guiding principle while performing deep small bowel enteroscopy should be to be gentle. This principle should be kept in mind for careful performance of enteroscopy, especially with deep sedation delivered by an anesthesiologist. Perform enteroscopy with extra care in high-risk patients/procedures.

  
  
• •
  

  Look for disease on the way in and look for trauma on the way out on DBE and SBE, but look for both disease and trauma on the way out on spiral enteroscopy, because collapsed lumen is needed for pleating the small bowel while advancing the scope, which significantly impairs visualization.

  
  
• •
  

  Carbon dioxide insufflation is preferred for enteroscopy, because of its rapid absorption and should be used if available. Significantly less gas is retained in the small bowel with carbon dioxide use compared with air insufflation. Furthermore, during DBE, fewer patients had severe pain with carbon dioxide than with air insufflation. No significant difference in pre-DBE and post-DBE partial pressure of oxygen in the blood and partial pressure of carbon dioxide in the blood was noted between the 2 groups. Although data have supported the safety and efficacy of carbon dioxide insufflation for endoscopy, most studies excluded patients with severe respiratory compromise or chronic obstructive pulmonary disease. Therefore, it would be prudent to consider room air insufflation in those who are potentially at risk for ventilatory compromise with carbon dioxide insufflation until the question is further studied.

  
  
• •
  

  Fluoroscopy can be helpful in providing information such as the scope tip position, scope tip movement, loop information, and guidance for loop reduction. However, routine use of fluoroscopy is not needed particularly with more experienced operators, although if available its use should be considered.

  
  
• •
  

  It is important to be aware of one’s own level of experience and available support. Studies reported that antegrade SBE has a faster learning curve than the retrograde route. Twenty to 35 cases of retrograde DBE are typically needed before achieving stable overtube intubation of the ileum. In addition, significant decrease in overall procedural and fluoroscopy time has been shown after the initial 10 antegrade DBE, whereas there was no change in timing for retrograde DBE.

  
  
• •
  

  An experienced enteroscopy team is essential. The enteroscopy team should be familiar with all the steps involved in these complex multistage procedures to avoid confusion and ensure success. DBE requires the repetition of a series of multiple maneuvers (inflating/deflating the scope and overtube balloons, advancing/reducing the scope, advancing/reducing the overtube). Therefore, confusion can easily occur, and valuable time can be wasted figuring out the correct stage of the procedure. Furthermore, pushing/pulling the scope/overtube with the wrong inflated balloon can contribute to adverse events. The SBE platform has only 1 balloon and requires fewer stages but nevertheless losing track of the proper maneuver sequence can easily occur. Spiral enteroscopy requires the active hands-on involvement of an assistant to rotate clockwise/counterclockwise and pull/push the spiral overtube. These maneuvers have to be coordinated with the enteroscope steering and advancement/shortening while the overtube is coupled or uncoupled from the scope. All deep enteroscopy procedures require an experienced team with a high degree of coordination.

  
  
• •
  

  It is necessary to be fully aware of particular potential enteroscopy-related adverse events to avoid these events from occurring.

Adverse events

The potential adverse events of enteroscopy are summarized in Box 2 . The reported incidence of adverse events for the 3 deep small bowel enteroscopy platforms is shown in Table 1 .

Box 2

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related posts:

Comprehensive Review of Adverse Events Associated with GI Endoscopy Minimizing, Recognizing, and Managing Endoscopic Adverse Events Adverse Events Associated with Percutaneous Enteral Access Endoscopic Retrograde Cholangiopancreatography–Related Adverse Events Endoscopic Retrograde Cholangiopancreatography (ERCP)-Related Adverse Events Closing Perforations and Postperforation Management in Endoscopy

Stay updated, free articles. Join our Telegram channel

Join