Cleveland Clinic Summit Gastroenterology. Assistant Professor of Medicine

Endoscopes have been used as early as the ancient Roman and Greek periods, however, it was in 1805 when Philip Bozzini made the first attempt to examine the urinary tract, rectum and pharynx using a tube that was called Lichtleiter (light guiding instrument). Subsequently in 1853, a French scientist, Antoine Jean Desormeaux gave the name ‘endoscope’ to an instrument that he used to examine the urinary tract. It was in 1960s that a new material called glassfiber was developed in the United States that revolutionized the use of endoscopes.

The last few years have seen significant advances in the field of endoscopy. The invent of high definition endoscopes, stents such as lumen apposing metal stents (LAMS) have made endoscopic procedures as the treatment of choice over most complex surgeries that was invariably needed for such medical conditions. We are currently in an era where laparoscopic Heller’s myotomy for Achalasia is getting replaced by endoscopic per-oral myotomy (POEM) as first line therapy for achalasia.

Some of the most notable technological advances already being used or in development stages in the field of endoscopy are

A)Lumen apposing metal stents (LAMS) – LAMS represents a new innovation in gastrointestinal endoscopy. These stents have a saddle shaped design and larger inner diameter that theoretically decreases the chances of stent migration. The initial use of LAMS was primarily to drain pancreatic fluid collections and walled off pancreatic necrosis by using 10 mm or 15 mm size LAMS. More recently 20mm size has expanded the use of LAMS to complex procedure – endoscopic ultrasound directed transgastric ERCP (EDGE) that enables endoscopic ultrasound (EUS) or endoscopic retrograde cholangiopancreaticography (ERCP) in patients with altered anatomy such as Roux-en-Y-gastric bypass (RYGB). Historically, these patients required surgical approach to perform ERCP. The other off label use of LAMS is to perform drainage of bile by creating connection between common bile duct and intestinal lumen (choledochoduodenostomy) in patients with malignant and unresectable bile duct obstruction after failed ERCP. EUS guided gall bladder drainage by using LAMS is also gaining popularity with encouraging results. More recently LAMS have also been used to create luminal connection between stomach and small bowel (gastrojejunostomy - GJ) in patients with unresectable malignant gastric outlet obstruction. Traditionally, surgical GJ anastomosis was the only option in this patients, however it carried a high morbidity of ~40%. The increasing use of LAMS have shown them to be safe and efficacious. Currently there is one LAMS (Axios, Boston Scientific, Marlborough, MA) that is food and drug administration (FDA) approved and available in the United States. Multiple other LAMS are available worldwide including the NAGI and SPAXUS stents (Taewoong Medical, Gyeonggi-do, South Korea).

B) Endoluminal therapies for Gastroesophageal reflux disease: A variety of endoscopic treatment modalities have been developed that are less invasive and safer than surgical fundoplication. The EsophyX device (Transoral incisionless fundoplication -TIF) creates a valve at the gastroesophageal junction and has been shown to be safe and effective. Other endoscopic therapies such as MUSE and Stretta are also gaining popularity after showing adequate safety profile and efficacy in several thousand patients.

C) Per-oral esophageal myotomy (POEM) and per-oral pyloromyotomy (POP or G-POEM). POEM as an endoscopic therapy for achalasia has been shown to equally efficacious with decreased morbidity and mortality compared to surgical Heller’s myotomy. More recently POP (G-POEM) is gaining popularity for the treatment of selected cases of gastroparesis, which has typically been a very difficult disease to manage.

D) Endoflip – A newer technological, minimally invasive device is being used in conjunction with high resolution esophageal manometry and barium swallow to diagnose motility disorders of esophagus such as achalasia. Endoflip has the added advantage of measuring the cross-sectional area and intraluminal pressure of the esophagus while under distension. Endoflip can also be used for pneumatic dilation of achalasia without the use of fluoroscopy. In future, it is predicted to diagnose different phenotypes of achalasia for specific management.

E) Artificial intelligence (AI). AI has revolutionized the field of gastroenterology and future will witness a surge in applications of AI. Researchers have shown how deep learning can assist in a variety of skills that physicians have been required to perform. An important application that is being tested worldwide is identifying polyps in a colonoscopy. Once a lesion is detected, computational alogrithms can predict polyp histology without the need for resection. AI is also being tested for early diagnosis of upper GI cancers, improving yield of wireless video capsule endoscopy to detect celiac disease, GI bleeding, Crohn’s disease, tumors, and ulcers.

F) Self-propelled colonoscopies: The Aer-O-scope (GI View Ltd, Ramat Gan, Israel) is a user-independent, self propelled, self-navigating colonoscope that is being developed for screening colonoscopies. Another selfpropelled colonoscope, the ColonoSight (Stryker Corp, Kalamazoo, MI) uses air assisted propulsion to create the forward force while the operator directs the scope using handles. This scope has disposable working channels. A pilot study has shown the safety and efficacy of these scopes.

G) Advances in imaging: A variety of newer techniques is developed in recent years to assist in early detection of dysplasia and neoplasia. Some of these techniques such as chromoendoscopy, narrow band imaging is widely being used. Others such as confocal laser endomicroscopy, autofluoroscence, light scattering spectroscopy, optical coherence tomography have shown promising results and will likely find a niche in routine endoscopy in near future.

These and several other technological advances in the field of endoscopy will bring a paradigm shift in the management of gastrointestinal disorders. Unfortunately, cost is still a prohibitive factor that limits the routine use of some or most of these therapies or devices, which is also one of the prime reasons for poor reimbursements. It is expected that with availability of more data regarding safety and efficacy and likely decrease in the cost of production of these devices, they will find a more mainstream use in the endoscopy space.