FormaldEhyde-free embalmeD Cadavers as a Training Tool in a mUltimodal Structured Curriculum in Laparoscopic SURGERY: a Randomized Clinical Trial

General surgery residents (GSR) face several challenges throughout their training, including learning and developing laparoscopic surgery skills (LSS). For GSR, who are constantly subjected to training in minimally invasive interventions, which require training in different skills than traditional surgery - such as minimal invasive manual dexterity, two-dimensional spatial perception and positioning different operating tools amongst others - simulation training (ST) plays an important role in the transition of knowledge acquisition and development of technical expertise during surgical training; The main challenge of ST in minimally invasive surgery is to recreate an environment that achieves both the basic physical parameters and provides decision-making experience during surgery, being its final objective mastering the use and location of the instruments to minimize possible errors during real life surgery. Since the inception of the concept of ST several simulation tools have been created to answer the challenges of training, however evidence suggest that frozen human or animal cadaveric models are the most preferred option by GSR.

Cadaveric models, frozen or fresh, share an anatomical similarity with real practice scenario and accurately reflect the characteristics of human tissues and thus are currently ideal for ST and development of (LSS), however, they present clear disadvantages and limitations that make their use difficult, specially the biological risk and the alteration of the mechanical properties of the bodies preserved by this technique, such as tissue rigidness, lack of elasticity and consistency, and the impossibility of achieving adequate pneumoperitoneum. In response to this issue, there are a variety of preservation techniques that do not use formaldehyde or use minimal amounts of this reagent, however these techniques present their own problems, such as elevated costs, complexity, and poor quality of preservation.

In previous work in our lab, a formaldehyde-free solution was developed and presented as a new preservation solution that claims to maintain -to a certain extent- the color, texture, rigidity, and elasticity of the tissues, allowing the clear identification of anatomical structures, and the creation of adequate pneumoperitoneum at representative low pressures for laparoscopic ST (+/- 5mmHg) after multiple tests. The corpses preserved with this solution can be used for surgical simulation, as they preserved the pose no biosafety risks comparable to those of fresh human tissues, can be reused, and pulse arterial flow can be generated by using an external peristaltic pump articulated with the system.

To our knowledge there is no evidence of the use of human cadaveric specimens preserved with formaldehyde free solutions in LSS development, whereby the aim of this manuscript is to evaluate the use of cadaveric specimens preserved with a formaldehyde free preservation solution as an alternative training tool to develop basic LSS and determine the existence of equivalence between this model and two widely used dry training models.

MATERIALS AND METHODS Design A single-center, single-blind, randomized educational intervention clinical trial was carried out to compare the use of formaldehyde free solution cadaver training in laparoscopic surgery with other traditional simulation surgery options. The trial was approved by our Institutional Research Board, prior to the beginning of the study (Act. No.201910224). Written informed consent was obtained from each participant and the CONSORT statement was followed.