Evaluation of three different positions of laparoscopic ports for Nissen fundoplication in rabbits

Abstract

Introduction: Paediatric laparoscopic surgery provides new challenges for surgeons; therefore there is a need for adequate training before performing procedures directly on patients. Several different models were designed for training, including both virtual simulators and live animals. However, training with animal models is the most appropriate method for surgical instruction, as it reproduces similar surgical conditions. The objective of this study was to establish the best localization of surgical ports for Nissen fundoplication in rabbit cadavers for both experimental and teaching purposes. Method: The research was conducted using six New Zealand white rabbit cadavers. The location of the trocars was established by two veterinary and one paediatric with experience in laparoscopy surgery. The model was evaluated by four paediatric surgeons. A 5 mm trocar was used, and a laparoscope of 5 mm and 30° attached to a microcamera was inserted. The abdomen was insufflated (to a pressure of 6-8 mm Hg). The placement of secondary trocars was conducted with direct visualization. Diverse factors were considered to establish the location of the trocars such the anatomy of the rabbit stomach and esophagus, laparoscopic Nissen fundoplication performed in rabbits with conventional laparoscopic instruments, and the length of paediatric laparoscopic instruments. Three approaches were repeated in order to locate a satisfactory view of the surgical area. Every position of the ports received a score: one point was scored when the instrumentation was crossed, one point when the organs were too far away to manipulate, and one point when the organs were too close to manipulate. The position was considered ideal when a zero value was obtained. Fleiss Kappa coefficient for 4 raters was used to estimate the level of concordance between observers. Results: It was possible to obtain a value of zero in the latter approach. The position of the trocars was established in the following way: the telescope port positioned at midline 1.6 cm caudal to the umbilical scar (2.0 cm with insufflation), and with the secondary ports placed slightly lateral to the third mammary glands. To establish the exact location of these trocars a point was established at 1.5 cm caudal to the telescope trocar. After forming an angle of 90°, 3.3 cm were measured on each side. These last measures were taken with the abdomen insufflated. Discussion or Conclusion: In this research was established the appropriate positions of the working ports, without causing fatigue of the operator’s wrist joint and with adequate space for comfortable movement. In addition, this would also reduce the use of live rabbits for the establishment of the ports in future research, accepting the concept of the three "Rs" for animal experimentation. With these models was obtained an excellent view of the surgical field without interference between the instruments and telescope.