Surgical Endoscopy

, Volume 22, Issue 1, pp 246–249 | Cite as

Millimetric laparoscopic surgery training on a physical trainer using rats

  • Arturo Minor Martinez
  • Alberto Chouleb Kalach
  • Daniel Lorias Espinoza
New Technology



To demonstrate the possibility of laparoscopic technique training and refinement at the millimetric level.

Material and Methods

A physical trainer and Winstar rats were used.


The training system is visually similar to pneumoperitoneum. The laparoscopic technique is perfected in a visual space illuminated by white light, with two-dimensional feedback and at a geometric level that allows for refinement of the technique.


It is possible to refine the technique at this geometric level at a low cost and without requiring laparoscopic equipment. In addition, optics tests indicate the possibility in the short term of refining the laparoscopic technique to the microanastomotic level.


Microsurgery Training Rat training 

Laparoscopic surgery demands specific abilities of the surgeon. The technique requires various psychomotor skills and abilities that can only be acquired through training [1]. The convergence of laparoscopy and microsurgery [2, 3] has shown that the combination of these two techniques is excellent for training and refinement of the technique [3]. However, currently there are no virtual or physical training systems [4] that offer this level of skill quality. Laparoscopic microsurgery training uses Winstar rats [3, 4, 5, 6] as models due to their low cost and easy handling and maintenance. The geometric characteristics of the rat volume allow surgeons to perfect their surgical skills quickly and immediately apply them to gynecologic, pediatric, urologic, vascular, and general surgery procedures [5, 6, 7, 8, 9]. Training procedures with this model always require complete laparoscopic equipment, including a light source, a camera, the laparoscope, and a blower [3, 4, 5, 6, 10], so refining the laparoscopic technique is not expensive because of the model, but rather due to the equipment and space requirements. In Mexico, hospital use of laparoscopic equipment is given priority, so its availability for microsurgical training is limited. Residents and surgeons, however, require training systems to refine their microsurgical techniques. For this reason, in this study we set out to design a training system that emulates millimetric laparoscopic surgery in two dimensions. Our optics results show that this is possible. The results also show that, with appropriate optics, the laparoscopic technique can be refined to the microanastomotic level.

Material and methods

A physical trainer for laparoscopic surgery was designed (Fig. 1). The trainer has a polar magnetic adjustment system for holding and positioning the optics (in, out, right, left, up, and down) (Fig. 1a), thus eliminating the need for an assistant to handle the camera. In addition, the inside of the trainer is illuminated by cool white light, so tissues and organs appear shadowless. Ports were added for the instruments (Fig. 1b). The 0° optics are provided by a commercial color minicamera (480-line resolution) with manual focus. Winstar rats in the 1.5–2 kg range were used as models. Models were anesthetized by means of a 10 mg/kg ketamine hydrochloride injection. Their gastrointestinal field was exposed (Fig. 2a), and the first model trainer was introduced to carry out the procedures (Fig. 2b).
Fig. 1

Design of the box trainer (a) optic holder, (b) instruments ports

Fig. 2

(a) Animal model inside the box trainer; (b) procedures with 5 mm instruments

The camera focus was initially set for work with 5 mm and 3 mm instruments. The focal distance was 8 cm. This distance allows for easy handling of the surgical instruments without interfering with the camera. The procedures carried out were: anastomoses, cutting, intracorporeal knots, and extracorporeal knots. The uterine horns were also explored. A lens arrangement was added to the camera to assess the possibility of working at the microanastomotic level; this produced a working area of approximately 1.5 cm2 with a focal length of 5 cm. Only two structures, the sciatic nerve (Fig. 4) and the small intestine (Fig. 5), were observed with this lens arrangement. Finally, rats were euthanized by means of a 40 mg thionembutal injection. During the procedures, the camera was adjusted to obtain the best view, as in laparoscopic surgery. Figure 2b shows an approach with the camera holder inclined at 48°, adjusted for this procedure. In Fig. 3a and b it is possible to see again the change of perspective in the same area of a piece of chicken with two different optic perspectives.
Fig. 3

(a) Chicken model seen with 90° inclined optics; (b) chicken model seen with 45° inclined optics (the same area in each case)

Fig. 4

Sciatic nerve and its ramifications observed through modified optics

Fig. 5

Small intestine observed through modified optics

Fig. 6

(a) Uterine horns of the rat; (b) correction of the box trainer system


The optics worked adequately for the 5 mm and 3 mm instruments; there was no significant difference between the real pneumoperitoneum and the proposed system. It was observed that, for microanastomosis, the optical system must offer greater focus and magnification, although the tests revealed that it is possible to work at this geometric level. The position of the ports proved to be excellent for procedures such as joining intestinal ducts, cutting, sutures, and intra- and extracorporeal knots. The position proved insufficient, however, for uterine horns (Fig. 6a), so two additional ports for instruments were made in the cover of the second model trainer (Fig. 6b). With these new ports it was possible to introduce the instruments to work ergonomically on this anatomical part of the rat.


Learning and training are inevitable steps for refining techniques in the laparoscopic specialty. Laparoscopic microsurgery, however, takes refinement of these techniques to a higher level. The strong magnification and the geometric level of the structures provide feedback that helps to control the surgical tremor and refine the suturing during training. Although they establish basic and advanced training protocols, virtual trainers do not offer the fine technical refinement of microsurgery. The system has been tested by a surgeon who is an expert in laparoscopic surgery and also teaches microsurgery. His comments have allowed us to refine the trainer system and, with his teaching experience, we are certain that our system will become a useful low-cost tool, considering the advantages that millimetric laparoscopic surgery training on real models offers both novice and experienced surgeons.


The proposed system offers millimetric laparoscopic surgery training on real models. The trainer workspace is visually similar to that of the pneumoperitoneum. There are no significant visual differences on the monitor between using the proposed system with an open rat as the work model and using complete laparoscopic equipment. Visual perspectives are easily adapted manually to the needs of the user in real laparoscopic surgery. No gas is required for inflation and, unlike in rat pneumoperitoneum, the trocars do not move under gravity during the procedure. The box trainer does not require instrument trocars, although it is possible to use them, as shown in Fig. 6. There are no perceptible undesirable visual movements and the surgery is carried out in two dimensions. Commercially available camera optics are the only limitation to working at the microanastomotic level. However, improved optics adaptations and the results herein clearly show that it is possible to lower learning costs at this geometric level. Such an option would benefit surgeons in this specialty by shortening training time and improving surgical skills, without requiring the infrastructure and cost of a laparoscopic system.



We would like to thank Dr. Ismael Jiménez of the Physiology Department of the CINVESTAV for his valuable comments and the facilities he provided to test the training system.


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Arturo Minor Martinez
    • 1
  • Alberto Chouleb Kalach
    • 2
  • Daniel Lorias Espinoza
    • 1
  1. 1.Departamento Eléctrica, Sección BioelectrónicaCentro de Investigación y de Estudios Avanzados del IPN (CINVESTAV IPN)San Pedro ZacatencoMéxico
  2. 2.Departamento de Cirugía, Centro MédicoAmerican–British Cowdray Medical Center, I.A.P. (ABC)Las AméricaMéxico

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