Minimally invasive endoscopic procedures are transforming gastrointestinal surgery by offering organ-sparing approaches for a range of pathologies. At the 2016 AGA Tech Summit, Dr. David Rattner updated attendees on three of these techniques – endoscopic submucosal dissection (ESD), peroral endoscopic myotomy (POEM), and endoscopic full-thickness resection (EFTR).
“It is likely that endoluminal treatments, combined with better understanding of molecular pathology, will decrease the need for radical surgical procedures for some common gastrointestinal conditions,” he said in an interview before the meeting, which is sponsored by the AGA Center for GI Innovation and Technology. Dr. Rattner is chief of the division of gastrointestinal and general surgery at Massachusetts General Hospital in Boston.
Dr. David Rattner
Dr. Jose Martinez put transorifice surgery in historical perspective and pointed the way forward in an accompanying presentation. “The collaboration with physicians and industry has really started to come along with the natural orifice approach,” said Dr. Martinez, professor of surgery at the University of Miami Health System.
Developed in the 1980s and substantially refined in the mid-2000s, ESD pioneered the endoscopic resection of entire intramucosal tumors without the need for open surgery. In a recent meta-analysis, ESD achieved significantly higher rates of en bloc resection than endoscopic mucosal resection (EMR), with significantly lower rates of local recurrence and comparable complication rates (World J Gastroenterol. 2014;20:8282-7).
ESD involves resecting the mucosa and much of the submucosa, while conserving the muscular layer of the esophagus. In contrast, during POEM, the surgeon intentionally divides the muscular layer, while the intact mucosa provides the barrier between the mediastinum or peritoneum and the esophageal lumen. The defining feature of POEM is the creation of a submucosal tunnel to access the muscle layer for myotomy without incising the skin.
POEM has been found highly successful for treating esophageal achalasia. In fact, in a recently published series of 500 cases, the success rate was 100%, even though the cohort included elderly patients and those with sigmoid esophagus and complex treatment histories (J Am Coll Surg. 2015;221:256-64). Two months post-treatment, average Eckardt scores had decreased by an average of 5.0, and lower esophageal sphincter pressures had fallen by nearly 50%. The adverse event rate was 3%, there were no fatalities, and improvements persisted 3 years later. “Nationwide, numerous centers have incorporated this technique and gotten significant positive results,” said Dr. Martinez.
“POEM will be shown to be as effective as any other currently existing therapy for the treatment of achalasia,” emphasized Dr. Rattner. Indeed, its success has sparked investigations of submucosal tunneling for other indications, such as tumor resection and pyloromyotomy for gastroparesis (World J Gastroenterol. 2014;20:17746-55).
Another cutting-edge technique is EFTR, described as a powerful tool not only for acquiring diagnostic tissue, but also for sparing some patients from surgery. Compared with ESD, it has the potential for higher diagnostic yield of full-thickness specimens, such as in cases of nonlifting adenomas, adenomas at difficult anatomic locations, T1-carcinomas, or submucosal colorectal tumors. For years, a lack of safe techniques and devices kept EFTR from entering routine clinical practice. But intensive research on natural orifice translumenal endoscopic surgery (NOTES) has helped propel innovations such as over-the-scope clips for closing incisions, and smaller, more maneuverable, over-the-scope full-thickness resection devices. Large-scale trials of EFTR are lacking, but in a recent report of 19 consecutive colonic submucosal tumors, EFTR enabled the removal of the entire tumor with capsule intact in 18 instances (Endoscopy. 2013;45[09]:770-3). Notably, colonic wall defects could be closed endoscopically in 16 of 18 cases.
“We are still a ways away from being able to perform EFTR on a routine basis, but new technologies are under development that will make this possible,” said Dr. Rattner. Agreeing that the future of transorifice surgery is bright and growing, Dr. Martinez said, “Strictures, obstructions, bleeding, foreign bodies are now fully resolved through endoscopic approaches.”
