28 Hellenic Journal of Surgery 2010; 82: 2 95 Abstract Background: Triangulation is difficult to perform in flexible endoscopy. Maneuvers required for natural orifice transluminal endoscopic surgery (NOTES) procedures are challenging, if not impossible, even with a double-channel endoscope, mainly because the optical axis and the instruments cannot move independently. The aim of this acute experiment in swine was to investigate whether triangulation can be improved by using three endoscopes inserted through different natural orifices. Method: Fourteen swine were subjected to laparo- tomy. Three endoscopes were introduced into the peritoneal cavity via the transgastric, transrectal and transvaginal routes, respectively, under direct inspection and assistance, through the open abdo- men. The laparotomy was then closed and pneu- moperitoneum was created. Using one endoscope for vision [eyes] and two for manipulations [hands] all combinations were performed in relation to the orifice of insertion and the role of each endoscope. The cooperation of the three endoscopes was tested for grasping and manipulating tissues as well as for exposing, dissecting and approximating structures. Results: The most efficient and ergonomic combina- tion for manipulations in the upper abdomen was found to be: endoscope “eyes” and one endoscope “hand” transrectally and the other “hand” transvag- inally; the most efficient for manipulations in the lower abdomen involved both endoscope “hands” transgastrically and endoscope “eyes” transrectally or transvaginally, in retroflex position. Conclusions: In NOTES triangulation can be im- proved for some manipulations by using three endo- scopes, inserted through different natural orifices. Keywords NOTES, Natural orifice surgery, Triangulation, Flexible endos- copy, Experimental surgery Ά Propedeutic Surgical Clinic and Anaesthesiology Department, Faculty of medicine Aristotelion University of Thessaloniki, AHEPA Hospital, Greece e-mail: elemakis@auth.gr Introduction Present-day flexible endoscopes and their acces- sories are designed to function within the gastroin- testinal tract. Since their introduction 50 years ago, they have continued to present three main disad- vantages; instability of the shaft, lack of force trans- mission and absence of triangulation. The concept of endoscopic triangulation is to sepa- rate the working hands (endoscopic instruments) from each other and to have the eyes (endoscopic vision) in-between the two hands. This seeks to rep- licate the experience of complex two-handed lap- aroscopic manipulations, which in turn are designed to mimic the way one operates in open surgery. Many maneuvers required for NOTES procedures are challenging or impossible to perform, even with a double-channel endoscope. This is partly due to the channels being in parallel and very close to each other, but mainly to the fact that the optical axis and instruments cannot move independently, but only together and simultaneously. While NOTES appears, at least theoretically, to be less invasive than laparoscopic surgery, including even single incision laparoscopic surgery, current endoscopes and endoscopic instrumentation are inadequate for performing complex surgical ma- neuvers within the peritoneal cavity. For NOTES to mature and reach human trials, one of the key elements needed is the development of a new gen- eration of advanced therapeutic endoscopes. These limitations have encouraged a lot of research and development on the part of the medical device industry. Many NOTES multitasking platforms are currently being developed, including advanced form of endoscopes [1, 2]. Because of the propri- etary nature of technological evolution and the typi- cally slow path before new technologies can be re- leased for commercial availability, it is very difficult for physicians interested in NOTES to use anything other than traditional flexible endoscopes. Consequently, we hypothesized that by inserting three flexible endoscopes through different natural orifices, the operating field could be approached si- multaneously from different directions which, theo- Improving Triangulation in Notes by Triple Access Katerina Kotzampassi, Vassilis Grosomanidis, Efthymios Eleftheriadis Received 24/08/2009 Accepted 08/11/2009 Experimental Study