WILLIAM O. RICHARDS, MD, ALFONSO TORQUATI, MD, NIK SEKHAR, MD, YASSAR YOUSSEF, MD
Endoluminal interventions are indeed evolving, and the endoscopic treatment of gastroesophageal reflux disease (GERD) represents the earliest application of this new surgical revolution . Four major technologies have emerged. Although each uses different approaches to augment the barrier function of the lower esophageal sphincter, the mechanisms may be similar. These technologies include endoluminal gastroplication (ELGP) (EndoCinch, Bard, Murray Hill, NJ), the full-thickness plication device (Plicator, NDO-Surgical, Mansfield, MA), radiofrequency energy delivery to the gastroesophageal (GE) junction (Stretta, Curon Medical, Inc., Freemont, CA), and injectable copolymer Enteryx (Boston Scientific, Natick, MA).
The NDO plicator creates a transmural plication that enhances the competency of the GE junction. The recently published results of the North American open-label trial demonstrate significant improvement in GERD-related quality of life and discontinuation of antisecretory drugs in 70% of patients .
The Stretta procedure delivers radiofrequency energy to the GE junction and to the cardia of the stomach. Treated patients experience decreasing frequency of transient LES relaxation and increased postprandial lower esophageal sphincter (LES) pressure . A randomized sham versus Stretta clinical trial showed a significant improvement in GERD symptoms 6 months after treatment .
Enteryx is a copolymer that is injected under fluoroscopic guidance into the muscularis propria of the lower esophageal sphincter. The material solidifies rapidly in situ and is presumed to alter the distensibility and the compliance of the GE junction . A recent randomized sham-controlled multicenter trial showed a significant reduction in distal esophageal acid exposure and improvement in GERD symptoms .
Endoluminal gastroplication (Endocinch) creates several plications at the GE junction that serve as antireflux barriers. Data from ELGP clinical trials are controversial. Although a recent study  demonstrated a significant reduction in GERD symptoms after ELGP, another clinical trial  showed unchanged heartburn symptoms or persistent use of proton pump inhibitors in 80% of the patients.
Endoscopic mucosal resection (EMR) is another emerging endoluminal application. EMR has been performed in 479 early gastric cancer patients . After resection, the local recurrence rate was 4.6% with a median follow-up period of 38 months. Although endoluminal ablation of Barrett's esophagus (BE) with argon plasma coagulation (APC) and photodynamic therapy (PDT) has been unsatisfactory [10,11], endoluminal ablation with radiofrequency energy is promising. The energy applied through a bougie-balloon device (Barrx Medical, Inc., Sunnyvale, CA) results in a mucosal ablation depth of 600 microns to 700 microns that preserves the muscularis propria layer. An early report about this device demonstrates successful BE ablation in 63% of patients with a 0% stricture rate . Even more amazing is the recent development of a device that performs full-thickness resection (FTR) of the intestine. This device allows resecting the bowel endoluminally without making an abdominal wall incision. Animals that underwent FTR survived for at least 21 days after the procedure .
Endoluminal treatment of esophageal leaks has also been successful. Leak closures have been achieved with endoscopic debridement/cleaning, application of fibrin sealant, endoclip placement, plugging, endoscopic suturing, and stenting of the esophagus .
A recent report  has shown the promise of endoscopic therapy for pancreatic necrosis and pancreatic abscess. Successful pancreas debridement through a gastrotomy was achieved in a small number of patients by using a therapeutic gastroscope. Transgastric gastropexy and hiatal hernia repair were also performed in a pig model . This technique requires endoscopic ultrasound (EUS) guidance. The use of EUS allowed extension to anatomical structures outside the wall of the gastrointestinal tract.
In the field of bariatric surgery, endoscopic restrictive procedures started with the creation of a vertical banded gastroplasty in animal models . Recently, Fogel  reported his experience with endoscopic vertical gastroplasty in humans. He demonstrated weight loss in all the 10 treated patients but noted that most sutures were gone 6 months to 9 months after the procedure. Thompson  has recently used the endoluminal approach to treat gastric bypass patients who had weight regain secondary to dilated gastrojejunostomy. He has performed endocinch tightening of the dilated gastrojejunostomy in 8 patients that has resulted in additional weight loss.
Another chapter in endoluminal therapies has recently opened, demonstrating the feasibility of the transgastric approach to the peritoneal cavity for diagnostic and therapeutic purposes. Liver biopsies, manipulation of intraabdominal organs, gastrojejunostomy, ligation of fallopian tubes, and transgastric cholecystectomy and cholecysto-gastric anastomosis have been performed in pigs [20,21]. The feasibility of advanced transgastric abdominal surgery has actually been proven by Drs. Rao and Reddy in India (personal communication). They performed transgastric appendectomies in 2 patients.
The search is now on for innovative designs and engineering improvements that have the potential to facilitate these interventions. New endoscopes are being developed. One device, called “Cobra” (USGI Medical), may provide additional benefits, such as a stable platform for triangulation of instruments and camera and the ability to use multiple instruments at the same time (Figure 1). This device should facilitate endoluminal and transgastric surgery . Although all these studies demonstrate the feasibility of the endoluminal approach, they also highlight many limitations of the present techniques. These include difficulty in exerting sufficient forward force and keeping the retroflexion view when the endoscope is in an unsupported position in the peritoneum, not to mention the risks of peritoneal infection from the gastrostomy site, the difficult visual orientation, and the present limits in endoscopic instrumentation.
In summary, it appears that we are at the dawn of a new era or another minimally invasive surgery “revolution,” one in which the surgeon operates in the abdomen with no skin incisions.
Figure 1. USGI Medical’s ShapeLock Endoscopic Guide and ShapeLock Cobra, a multilumen ShapeLock Guide with articulating instrument arms and off-axis visualization.
Address reprint requests to: William O. Richards, MD, Vanderbilt University Medical Center, D5219 MCN, Nashville, TN 37232-001, USA. Tel: 615 322 7555, Fax: 615 343 9485
William O. Richards, MD, is Professor of Surgery and Director of Laparoendoscopic Surgery at Vanderbilt University Medical Center in Nashville, Tennessee. His interests include minimally invasive and endoluminal surgery for GERD, Achalasia, and obesity.
Alfonso Torquati, MD, MSCI, is Assistant Professor of Surgery and Director of Foregut and Bariatric Surgery Research Program at Vanderbilt University Medical Center in Nashville, Tennessee. Minimally invasive and endoluminal surgery for GERD, Achalasia, and obesity are his primary interests.
Nik Sekhar, MD, is an Instructor of Surgery and Laparoscopic Surgery
Fellow at Vanderbilt University Medical Center in Nashville, Tennessee.
His interests are in minimally invasive and endoluminal surgery.
Yassar Khalil Youssef, MD, is a Laparoscopic Surgery Fellow, Division of GI and Laparoscopic Surgery, at Vanderbilt University Medical Center in Nashville, Tennessee. His interests include minimally invasive and endoluminal transgastric surgery.
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