Experienced teaching points

Clinical Pearls

Variable stiffness should be used dynamically: engage stiffness to push through a floppy or elongated sigmoid, but immediately disengage it to allow the colon to 'accordion' over the scope once the tricky segment is traversed.
Never apply variable stiffness while the colonoscope is torqued or locked in an alpha loop, as this anchors the scope in a twisted, non-anatomic position, impeding advancement and drastically increasing the risk of mucosal laceration or perforation.
Applying stiffness while the scope tip is at the hepatic flexure can help 'straighten' the transverse and splenic flexures, providing the necessary rigid backbone to push the tip cleanly into the cecum.

What is the optimal way to use variable stiffness colonoscopes in difficult colonoscopies? Have you had any adverse events?

Variable stiffness is a wonderful addition to colonoscopes, especially pediatric colonoscopes, which I use for most colonoscopies in the hospital where I have these scopes. At my other hospital we have a different scope brand (Fujifilm), which are also wonderful scopes. Variable stiffness is especially useful in floppy colons, elongated sigmoid colon and long colons that make turns in the pelvis. I advise to use variable stiffness mode in a “dynamic” fashion, meaning that once you feel there is some “floppyness” or you are about to enter the transverse coming from the descending colon, you apply more stiffness. Once you have mastered the area, it’s advisable to remove the stiffness and allow the colon to move into your scope (to “accordion”) into the scope. Do not apply variable stiffness while the scope is torqued or in alpha or reverse alpha loop, as this may increase the chances of laceration, but mainly may impede you advancing as you “lock” your scope in a twisted position. Also, do not start insertion in the rectum with a stiffened scope. The scope should be floppy when it is pushed from rectum to recto-sigmoid and sigmoid colon. I also like to use variable stiffness when located at the hepatic flexure. That “final” stiffening of the scope “straightens” the transverse and splenic flexure, adding the last needed push for the scope tip to conquer the hepatic flexure and reach the cecum. Once in the cecum I take the stiffness off and continue travel to the ileum.

What do you think of the Long Term POEM success?

There is little long-term data. So far, we know that a significant amount of patients develop severe reflux esophagitis and stricturing esophageal disease. I still think that POEM is a good alternative for patients who are poor surgical candidates, but am still not 100% convinced that it's the only therapy for achalasia, especially with much more long-term data from surgical interventions such as Heller myotomy.

Peroral endoscopic myotomy (POEM). POEM is one the most significant progresses in interventional gastrointestinal endoscopy. The elemental concept of POEM is the performance of endoscopy between the muscle layer and the submucosa. As endoscopy is not performed endoluminally nor in the Peritoneum, pleural or mediastinal spaces it is properly called “third-space endoscopy” or submucosal tunneling pro- cedure. The figure shows the essential steps for POEM, including proper creation of a submucosal cushion, incision of the mucosa and submu- cosa, endoscopic dissection and tunneling through the submucosal layer and final endoscopic myotomy. As expected submucosal tunneling techniques are also useful to perform resection of submucosal and muscular tumors per-oral endoscpic tumor excision (POET) and submucosal tunneling endoscopic resection (STER).

Ref.: 1. Inoue and Maydeo. Endoscopy 2019; 51: 1010–1012

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