Up to Speed on Ultrathin Endoscopes

Ultrathin endoscopes have proven to be invaluable instruments for examining the upper GI tract of patients with challenging anatomy, even if that wasn't their intended application. "Upper endoscopy exams performed with a standard endoscope passed through the mouth require sedating the patient, and ultrathin scopes were originally designed to facilitate sedationless upper endoscopies with the transnasal approach," says Vivek Kaul, MD, FACG, FASGE, AGAF, a professor of medicine at the University of Rochester (N.Y.) Medical Center & Strong Memorial Hospital. "But the method has failed to catch on, perhaps because patients have expectations to receive sedation and anesthesia when undergoing exams."

The push for transnasal endoscopy was intended to mitigate risks related to sedation and anesthesia, which account for a majority of complications that occur during upper endoscopy procedures. "Sedationless exams are also easier for patients, who undergo the procedures and can drive themselves home or to work as soon as it ends."

It's a great concept, at least in theory. Douglas Adler, MD, FACG, AGAF, FASGE, says more practical applications of ultrathin scopes involve maneuvering around complex strictures and post-surgical anatomy in upper GI tracts or use in pediatric patients who can't tolerate an adult scope.

Dr. Adler, a professor of medicine at the University of Utah School of Medicine and Huntsman Cancer Center in Salt Lake City, believes the primary benefit of ultrathin scopes is that they can be used in office-based settings. "But very few gastroenterologists perform office-based endoscopy procedures because they're used to performing a complete upper examination, which includes the esophagus, stomach and the beginning segment of the small bowel," he says.

Enhanced imaging helps physicians identify lesions, better characterize the mucosal lining and facilitate mapping of abnormal anatomy.
— Vivek Kaul, MD, FACG, FASGE, AGAF

Most in-office sedationless exams include the esophagus and perhaps the beginning portion of the stomach due to patient tolerance, according to Dr. Adler. "Culturally, physicians feel like esophageal screening procedures are incomplete exams," he says. "What if they miss a stomach ulcer they would have seen with a standard endoscope?"

Dr. Kaul says ultrathin endoscopes are ideally suited for performing exams in patients with narrowing at the upper esophageal sphincter and the gastroesophageal ?junction, and in the pylorus and duodenum. "That's where these devices are most helpful," he explains. "They let physicians complete examinations that would not be possible using standard endoscopes."

Physicians who run into difficulty moving a colonoscope through narrow areas of the colon often opt for a standard gastroscope, which has a smaller diameter and the rigidity needed to maneuver through the colon. Dr. Kaul says ultrathin endoscopes, which are too narrow and too flexible, are not typically used during colonoscopy exams.

Ultrathin scopes can prove useful in facilitating stenting for colorectal malignancies in the lower GI tract, however. "Physicians who need to access a tumor beyond a narrowing of the tract during a colonoscopy, but are unsure of where to place the guidewire, can remove the colonoscope and insert an ultrathin gastroscope, enter the proximal bowel and place a guidewire beyond the narrow segment," explains Dr. Kaul. "They then remove the gastroscope and slide a colonoscope back over the guidewire to reach the tumor."

Dr. Kaul adds that physicians can opt for ultrathin scopes when evaluating fistula openings in the colorectal tract such as the connection between the colon and the urinary bladder. "The scopes provide physicians with the opportunity to better evaluate the fistula tract, obtain a better anatomical perspective and localize cancerous growths," he explains.

Ultrathin scopes are used to facilitate esophageal stenting in the upper GI tract for duodenal stent placement, according to Dr. Kaul. He says that application addresses gastroduodenal strictures caused by malignant or benign growths in the stomach, pancreas or duodenum.

Dr. Kaul says physicians are also able to introduce super-slim scopes through a percutaneous biliary tract created by interventional radiology and into the liver to sample tumors, facilitate stent placement and break stones using laser or electrohydraulic lithotripsy.

Upgrades to the imaging capabilities of ultrathin scopes continue to evolve. Camera chips at the tips are more sophisticated and offer high-definition resolution, which has come online in the last three to four years. The latest models also feature electronic chromoendoscopy, a technology that provides contrast enhancement of mucosal surfaces. "The enhanced imaging helps physicians identify lesions, better characterize the mucosal lining and facilitate mapping of abnormal anatomy," says Dr. Kaul.

When examining growths in the duodenum, for example, advanced imaging helps physicians differentiate between a benign mucosal, hypoplastic polyp, and fundic and adenomatous polyps. Advanced imaging also helps physicians exam more subtle areas of abnormalities on the mucosa, which, according to Dr. Kaul, could prove useful when following the American Society for Gastrointestinal Endoscopy updated guideline for the screening and surveillance of Barrett's esophagus. The guideline, released in September 2019, calls for identifying this precancerous condition in its early stages and monitoring changes in the cell lining of the esophagus to provide the best chance of successful treatment and outcomes.

"During screenings for Barrett's esophagus, physicians who are looking for precancerous lesions appreciate the extent of the Barrett's segment much better with electronic chromoendoscopy than with standard high-definition imaging," says Dr. Kaul.

High-definition imaging allows for super-thin endoscopes to be used for non-traditional applications, according to Dr. Kaul. For example, he says the small-caliber endoscopes can, in many cases, be placed directly into the bile duct through the duodenal opening for evaluation of the biliary tree. This direct peroral cholangioscopy technique is more effective than indirect peroral cholangioscopy, notes Dr. Kaul.

The functionality of ultrathin endoscopes has also improved in recent years. Older models were outfitted with a single dial that physicians used to direct the scope's tip in two-way deflection. The latest models have dual-dial, four-way deflection — similar to the controls found on standard colonoscopes and upper gastroscopes — that facilitate movements in tight spaces.

Dr. Adler says all major endoscope manufacturers make ultrathin upper endoscopes that are highly functional, and notes ultrathin models should come with all the features of standard flexible scopes. "Ultrathin scopes must be comparable to a standard scope in terms of maneuverability, image quality and image capture," says Dr. Adler. "A scope that lacks any of those features would be disadvantageous to use."

The devices are delicate and expensive instruments, and susceptible to the same level and degree of breakdown as all flexible endoscopes, points out Dr. Kaul. "They require constant care and high-level disinfection with the same reprocessing guidelines and processes as standard scopes," he says.

Ultimately, Dr. Kaul believes ultrathin endoscopes are important instruments to have in any endoscopy suite. "They help physicians perform many different procedures at the very basic level and lead to successful procedures that otherwise would have ended in failure," he says. OSM