Intubating the terminal ileum (TI) during colonoscopy allows for a complete examination of the large bowel and a portion of the small intestine. However, successfully entering the ileocecal valve to access the TI can be one of the most challenging parts of the procedure. In this in-depth blog post, we will review recommendations for TI intubation, tools to aid the process, and a variety of techniques gastroenterologists can use to improve their success rate.

When Should We Intubate the Terminal Ileum?

Opinions vary on whether intubating the TI should be standard practice for average-risk screening colonoscopies. The primary reason to enter the TI is to inspect for lesions like neuroendocrine tumors that can arise in the distal ileum. These types of tumors often metastasize early, even when small, so identifying them before progression is ideal. However, the incidence of clinically significant findings in the TI for asymptomatic average-risk patients undergoing screening is quite low, estimated at around 1 in 5,000 to 6,000 procedures. Due to this low yield, some experts argue intubating the TI should not be considered a requirement for standard of care in routine colon cancer screening.

On the other hand, certain clinical situations do warrant diligent efforts to intubate the TI. This includes patients with a history of Crohn’s disease, small bowel tumors, previous ileal resection, or other risk factors for ileal abnormalities. Additionally, if an abnormality of the ileocecal valve or TI is seen on imaging, intubation of the TI for direct inspection is recommended. In these types of clinical scenarios, taking steps to improve TI intubation success is justified.

Tools to Aid Intubation of the Terminal Ileum

Using the right equipment can greatly facilitate entry into the TI. The diameter of the colonoscope’s distal tip is a key factor. Standard adult colonoscopes may have a diameter of 12-13mm, which can be difficult to advance through the ileocecal valve orifice. Switching to a smaller diameter pediatric colonoscope or ultra-thin adult colonoscope in the 9-10mm range can help.

Another tip is to remove any attachments at the scope’s distal end if possible. Devices like transparent distal attachments or Endocuff attachments, while useful during insertion and withdrawal, increase the tip diameter. Temporarily taking these off can enable smoother passage through the ileocecal valve.

Techniques for Intubating the Terminal Ileum

With the right scope, there are several techniques gastroenterologists can use to improve TI intubation success:

Deflate the Cecum
Partially deflating the cecum helps orient the ileocecal valve so the orifice points towards the anus. This makes the valve opening visible and accessible as you approach it. Avoid over-insufflation of the cecum, which can make the valve orifice disappear from view.

Direct Approach
Once you see the valve orifice, drive the scope directly into it instead of using indirect maneuvers like the “bow and arrow” technique. Carefully advance the scope so the tip wedges between the lips of the valve orifice, then gently push forward into the TI.

Underwater Technique
This involves removing all air from the cecum and replacing it entirely with water. The water environment helps relax and stretch open the ileocecal valve, while also orienting the orifice anteriorly. The valve opening becomes more evident, allowing a direct approach. This is extremely useful when a larger diameter scope or attachment is present.

Retroflexion Technique
If the above maneuvers fail, turning the scope tip backwards into a retroflexed position in the cecum can sometimes permit entry into a difficult valve orifice. Once the orifice is accessed in retroflexion, promptly straighten the scope while applying external abdominal pressure to advance deeper into the TI.

A Multipronged Approach

Gastroenterologists can combine techniques like using a pediatric colonoscope and the underwater method together when confronted with a challenging ileocecal valve. Patience and the stepwise use of different techniques is key to eventually gaining entry into the TI in difficult cases.

In conclusion, intubating the terminal ileum may not be mandatory for average-risk screening colonoscopies but is recommended in certain clinical scenarios. Multiple techniques are available to improve success, including equipment choices like smaller diameter scopes and strategic maneuvers such as the underwater approach. Mastering these techniques expands endoscopic skills and enables complete inspection of both the colon and distal small bowel.

Frequently Asked Questions About Intubating the Terminal Ileum

What is the terminal ileum and why is it important to intubate during colonoscopy?

The terminal ileum (TI) is the last portion of the small intestine before it connects to the large intestine. Intubating the TI allows the endoscopist to examine the distal end of the small bowel for abnormalities. This is particularly important for detecting rare neuroendocrine tumors that can arise in the TI.

Is it mandatory to intubate the TI for every colonoscopy?

No, there is some debate over whether intubating the TI should be standard practice for average-risk screening colonoscopies. Since the incidence of significant findings is low for asymptomatic patients, some experts argue it is not required in routine cases. However, it is advised to make efforts to intubate the TI when certain risk factors are present.

What techniques can help with intubating the TI?

Using a pediatric colonoscope or ultra-thin adult scope can decrease the diameter and ease insertion. Removing attachments at the distal end also helps. Deflating the cecum, the underwater technique, and retroflexion are other useful maneuvers. Combining techniques, like a smaller scope with the underwater approach, can further optimize success.

How do you perform the underwater technique?

This involves removing all air from the cecum and completely filling it with water. The water environment helps relax and open the ileocecal valve while also repositioning the orifice anteriorly, making it easier to see and enter the orifice.

When should I try the retroflexion technique?

Retroflexion in the cecum can permit entry into a difficult ileocecal valve, but it takes practice to maintain position when straightening the scope. Therefore, retroflexion is best reserved for cases when other preferable techniques have failed initially.

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