Triangulation: the holy grail of endoscopic surgery?

Abstract

Interventional endoscopy has recently breached the boundaries of the gastrointestinal lumen, entering into the peritoneal cavity to perform natural orifice translumenal endoscopic surgery (NOTES) [1–3]. NOTES is defined as a surgical procedure in which visualization, dissection, and organ retraction is performed with flexible endoscopic instruments through the natural orifices of the body. NOTES is theoretically scarless, and therefore, incisional hernias and associated wound infections are avoided. Other potential benefits include reduced surgical trauma resulting in less postoperative pain and adhesion formation compared with laparoscopic surgery [3]. Currently, no randomized, controlled trial has demonstrated a true advantage of NOTES compared with laparoscopic surgery and the proposed benefits remain speculative. Thus far, and largely in animal laboratories, gastroenterologist and surgeon have opened and closed the gastrointestinal wall, peered into the peritoneal cavity, and demonstrated feasibility of organ resection [4, 5]. Why is it that despite being eager to perform endoscopic intraperitoneal surgery, gastroenterologists and surgeons have only scratched the surface of this novel surgical approach, which is still nowhere near primetime? When experts try to predict how NOTES could function, they normally look at the principles of laparoscopic surgery. Laparoscopic surgery is performed with careful placement of trocars to optimize exposure and to permit triangulation. It is assumed that triangulation is necessary to create traction and countertraction and that this physical principle is what permits appropriate retraction, dissection, or suturing. Accordingly, many experts have suggested that flexible endoscopic surgery will need to emulate the same principles of triangulation to be an effective surgical approach [6, 7]. Several articles have proposed a triangulating endoscope as a key element for the success of NOTES [3, 8–11]. Consequently, NOTES research in recent years has been dominated by major efforts to develop devices and platforms that simulate triangulation and surgical tasks based on how they are performed in the laparoscopic environment. The first patent describing the concept of an endoscope with angulating end-effectors was filed by Mitsui for Olympus as early as 1974 (United States patent number 3,915,157). This patent was subsequently further refined and advanced to a prototype triangulating endoscopic platform filed for patent in 1999 (Matsui et al., United States Patent number 6,352,503). Despite these enduring efforts to build a triangulating endoscopic platform, no such device has become available for clinical use, and those among us who had the opportunity to work with triangulating prototypes have realized that triangulating end-effectors at the tip of a flexible endoscope may have inherited more problems than solutions. Using the flexible translumenal instead of a laparoscopic approach for intraperitoneal surgery does not nullify surgical principles and certain tasks, such as robust organ retraction and classic suturing, will likely require triangulation. There D. von Renteln (&) T. Rosch Department of Interdisciplinary Endoscopy, University Hospital Hamburg-Eppendorf, Martinistrase. 52, 20246 Hamburg, Germany e-mail: renteln@gmx.net