Advanced Endoluminal Surgery: Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection

Emre Gorgun

ENDOSCOPIC MUCOSAL RESECTION

Perioperative Considerations

Procedure can be performed in regular endoscopy suites under sedation or in the operating room under general anesthesia.
The patient should be positioned based on the location of the lesion.
Position the lesion at 6 o’clock (ie, inferior midline).
The colonoscope is introduced, and a standard colonoscopic examination is first performed to evaluate for other pathology.

Technique

After standard colonoscopic examination, locate the lesion for endoscopic resection.
Methylene blue or indigo carmine dye is added to the injectate to establish better visualization between the lesion and the normal mucosa (Fig. 4-1).
Alternatively, premixed solutions such as Eleview can be used.
After locating the lesion, the special injectate is injected between the mucosa and the submucosa.
Start injecting from the area that is difficult to access (typically start from oral/proximal site). Adjust needle tip to be tangent to the lesion.
Solution is injected circumferentially around the lesion with a 2-mm margin.
Be dynamic while injecting and adjust depth and amount of the injection based on visual cues (Fig. 4-2).

FIGURE 4-1 ▪ Hypromellose solution that can be used to prepare the injectate.

FIGURE 4-2 ▪ Injection is started circumferentially around the lesion and continued until adequate mucosal elevation is observed.
Injections are finalized when the lesion is adequately elevated and is suitable for resection.

Select the snare size and shape according to the lesion dimensions (Fig. 4-3).

FIGURE 4-3 ▪ There are various snare types available based on size and shape. Appropriate snare should be selected based on lesion characteristics. (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2019. All Rights Reserved.)

Snare removal can be done piecemeal or en bloc based on the size and location of the lesion.
Start snaring from the edge that is difficult to access. Incorporate 2-3 mm of normal mucosal margin when resecting.
Open the snare fully before aiming the lesion and position the snare on top of the lesion (Fig. 4-4).
After including the lesion in the snare that will be resected, hold the snare parallel and tilt, close the snare tightly.
During snare removal, perform additional injections when necessary. This may be required if the injectate diffuses, or if additional lift and demarcation of the lesion, are required.
Repeat until the lesion is completely removed.
After each snaring, clean the resected area with normal saline and visualize the site for any defects or remaining lesions.
Use snare-tip coagulation or coagulation forceps to establish hemostasis and reduce adenoma recurrence (Fig. 4-5).
See Video 4-1 for example of endoscopic mucosal resection (EMR).