Natural Orifice Transluminal Endoscopic Surgery: The Future of Gastrointestinal Surgery

Considering the continued evolution of flexible endoscopy into more of a therapeutic tool and, at the same time, the growing awareness that the degree of invasiveness of surgery has a large impact on patient outcomes, it was perhaps inevitable that endoscopy and surgery would eventually work together (Figure 1). Accelerating technologic developments mean that this theoretic point of fusion has a potential clinical application. It is conceivable that the current generation of surgical endoscopists is on the verge of witnessing a true paradigm shift, which is being referred to as Natural Orifice Transluminal Endoscopic Surgery (NOTES). The potential of flexible endoscopy to perform therapeutic procedures beyond the wall of the gastrointestinal tract was recognized as early as 1980 when the first transluminal feeding gastrostomy was described by Gauderer et al.1 Kozarek et al2 published the first report of successful endoscopic drainage of pseudocyst in 1985. On the surgical side, the established benefits of laparoscopic procedures over conventional laparotomy in terms of patient recovery and perioperative morbidity, the increasing skill set of advanced laparoscopists, and the comfort of practitioners in performing complex surgeries using video imaging and pneumoperitoneum raised the possibility of replicating such operations endoscopically. The first report of oral peritoneoscopy done in animals was published by Kalloo et al3 in 2004. Since then, multiple investigators have used transluminal flexible endoscopy in animal models to perform various intraperitoneal procedures, ranging from tubal ligation to splenectomy3–8 (Table 1). There have been additional reports of clinical cases, but no publications about them have appeared. On the basis of these initial reports exploring both the scope and feasibility of NOTES, the transluminal approach appears to have tremendous potential. However, several important issues, including the safety of this approach and whether it will provide significant patient benefit in terms of postoperative recovery compared with laparoscopy, must be resolved before the new technique is widely introduced into clinical use. Additionally, it is recognized that early use of this approach by surgeons or gastroenterologists who might be relatively inexperienced in the particular skill sets required might lead to serious complications, which should definitely be avoided during the infancy of this concept. To head off such errors and to develop NOTES in a responsible and safe manner, a working group of 14 leading laparoscopic surgeons and endoscopists from the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) and the American Society for Gastrointestinal Endoscopy (ASGE) met in July 2005. The working group was named Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR). The prime goal of the meeting was to produce a document that would serve as a guide for responsible development of NOTES. In the white paper that the group subsequently published, NOSCAR discussed in detail the potential challenges to safe use of NOTES in clinical practice and outlined guidelines for investigators working on NOTES and criteria for expanding participation in NOSCAR.9 Figure 1 Merging of surgery and therapeutic endoscopy Table 1 NOTES procedures described to date Will Natural Orifice Transluminal Endoscopic Surgery Offer Advantages Over Current Surgical Techniques? When the laparoscopic approach was introduced, it was initially argued that it might not provide any benefit to the patient other than better cosmesis. Since then, multiple benefits of laparoscopic surgery, including a decreased neurohumoral stress response,10 decreased immunosuppression,11 less pain, faster recovery,12 and a decreased incidence of wound-related and pulmonary complications, have been recognized.13 In spite of initial skepticism then, today laparoscopy has become a standard approach for most general surgical, gynecologic, and urologic procedures and has been widely accepted for several oncologic procedures as well. NOTES should provide all of the above-mentioned advantages of laparoscopic surgery. In addition, the elimination of all abdominal wall incisions might have several potential benefits. Wound infection is a common surgical complication, with a reported incidence ranging between 2% and 25%, depending on the type of surgery performed.14,15 This has a tremendous adverse impact on patient recovery and health care costs.16 Eliminating all skin incisions would completely eliminate this risk. Incisional hernias and increasing rates of postoperative adhesions are thought to correlate with the size of abdominal wall incision. The incidence of incisional hernia is substantially lower with laparoscopic procedures, where incision size is much smaller than for open surgery, and should be eliminated with NOTES (4%–18% with open surgery17–19 vs 0.2%–3% with laparoscopic surgery20). Similarly, the reported rates of small-bowel obstruction due to adhesions are also significantly lower after laparoscopic surgery compared with open surgery (3.3% vs 7.7%) and will perhaps be further decreased with NOTES.21 Reducing or eliminating these complications would be an important improvement in patient care as well as a major cost savings to society as a whole. Other potential benefits that NOTES has been theorized to offer are decreased postoperative pain, less need for postoperative analgesia, shorter hospital stay, and faster recovery. Additionally, NOTES may have several advantages in specific subpopulations. It may provide an easy alternative access to the peritoneal cavity in morbidly obese patients, in whom traditional open or laparoscopic access can be difficult because of abdominal wall thickness, and could possibly reduce the lifetime risk of incision-related complications in children.22