Organic bench model to complement the teaching and learning on basic surgical skills

PURPOSE: To propose an organic bench model made with fruits/vegetables as an alternative to complement the arsenal of simulators used in the teaching and learning of basic surgical skills during medical graduation and education. METHODS: They were described the training strategies, through the use of fruits (or vegetables) to the learning of different techniques of incision, sutures, biopsies and basic principles of reconstruction. The preparation of bench model, the processes of skill acquisition, feedback and evaluation were also delineated. RESULTS: A proposal for teaching based on an organic model with training delivered in multiple sessions, with increasing levels of difficulty, and with feedback and evaluation during all the process was structured. CONCLUSION: The organic model, being simple, versatile, portable, reproducible, readily available, and having low cost, is another option to complement the existing simulators for teaching and learning of basic surgical skills.


Introduction
Based on the assumption that general practitioners are routinely faced with situations that require implementation of ambulatory surgical procedures 1,2 , and that most physicians do not get satisfactory surgical skills during their academic training 3 , it is necessary to establish a training program aimed at the teaching and improving of these technical skills to undergraduates and newly graduates 1,2 .Although different simulators have been described to provide this training 4 , none of them is complete.
In an attempt to find a simulator that presents minimum requirements for storage and that can be easily discarded, one that is simple, versatile, portable, reproducible, affordable, easy to acquire, with a low financial cost, and that permits the evaluation of practice with feedback for improving the skills/surgical technique, this study proposes the use of an organic bench model made with vegetables/fruits for teaching-learning during medical school, as a complementary alternative to the existing bench simulators.

Teaching-learning with the organic bench model for the training of basic surgical skills
The organic model can be used for training medical students who never had contact with basic surgical skills and for those who had some contact with these skills but need to improve Training should be directed to the student.In the beginning of the process, the goals can be similar for all group members.However, in subsequent sessions, the proposals can vary according to the differences in the acquirement of students' abilities.As the student acquires simpler skills, the degree of difficulty should be increased.
The basic objectives proposed and described in this study include handling of surgical instruments, training of suture techniques, incisions, surgical resection with or without safety margins and incisional/excisional biopsies, and basic principles of reconstruction, such as "grafts".

Making an organic bench model
To make the model, it is only needed to have the chosen fruit (or vegetable), a plate of Styrofoam, needles (size and quantity vary according to fruit or vegetable) and a ballpoint pen or marker.The fruits (or vegetables) are acquired in commercial establishments, and preference should be given to those which have thicker peels and are not softened.The choice of a specific fruit or vegetable is variable.For training of sutures it is preferable to use orange, lemon or eggplant.Lemon presents the risk of staining the skin if there is exposure to sunlight after contact.On the acquirement of skills such as removal of debris in spindles and "skin" biopsies, it is preferable to use banana, lemon or orange.
Differences in costs and seasonal availability of products may also affect the choice.

Training incisions and sutures
Incisions and sutures can be trained concurrently.For this, students make a mark on the peel of the fruit or vegetable, and then make the incision in the previous mark, simulating an

Training of basic surgical techniques for the handling of "skin lesions"
The simulation of different skin lesions, through drawings on peels of the chosen model, for students to make their respective diagnoses and/or treatment and repairs, makes the surgical training (resections with and without safety margins, incisional/excisional biopsies, and grafts of "skin") more attractive and rewarding (Figure 3).Each of these procedures should be taught separately to the student, so that he can learn about every technique in details.
For example, by simulating a non-melanoma skin cancer, the student should do the marking of safety margins, the incision in the margins, the removal of the surgical piece and the correction of the defect with the graft or flap advancement/rotation (Figure 4).(A) Simulation of a "skin tumor" and (B) of its surgical resection.The "skin tumor" should be resected intact with full excision of thickness of peel fruit.This surgical procedure must be careful to avoid that the rind of the fruit becomes excessively damaged and/or torn.FIGURE 4 -Organic model for the teaching and learning of basic principles of reconstruction.Simulation of a correction of the (A) defect formed by placing a (B) "skin graft" or by a (C-D) "rotation flap".The stitches were posed only to simulate the final result.It's just a demonstration on the basic principles of "surgical flaps", without placement of stitches for coaptation of the "edges", since for this it is necessary to place tension on the "tissue", and the model does not show this feature; the rind of the fruit/vegetable lacks the necessary elasticity to withstand this tension.

Feedback and evaluation
Feedback and evaluation are important to improve the learning of each taught technique.Feedback should be performed during and after each stage of training in the classroom, or at specific times scheduled after the training at home, in which the student will improve the taught fundamentals on his own.Instructors must evaluate each motion, searching for specific items that are not being adequately carried out (errors and failures) so that they provide a constructive feedback to students, enabling them to learn from their mistakes and as a result they can acquire skills over time.The marking lines can serve as an evaluation parameter; one should point out and correct incisions outside them.Regardless of the feedback, it is important to encourage students to clear up their doubts during training and after completion of extracurricular tasks.
The Global Rating Scale 6 , which assesses students during performance of tasks in eight main areas (Table 1), can be used to evaluate and monitor the gain of students' abilities; each area presents a five-point scale (one corresponds to a minimum score and five corresponds to a maximum score), with a maximum total score of 40.Instructors can apply this scale at the end of each teaching session and in subsequent sessions they can follow the acquirement of students' skills and the specific points, among the eight evaluated ones, that deserve greater attention.The assessment can also be used to ensure that most students have trained and understood the proposed techniques.For an individual task, the candidate must achieve a score of 24 or more to be considered competent 7 .TABLE 1 -Global Rating Scale 6,7 .

Discussion
Although the acquisition of basic techniques and surgical skills have been only a part of the surgical learning, such knowledge is relevant to the general practitioners because it has important implications in the care of patients.Despite the importance of the topic, these skills are not acquired by a large percentage of students during their training 3 .
Since nowadays the traditional method of training based on practice with patients violates ethical and medico-legal issues The improvement of the technique is also possible based on performance errors 13 without the worry of harming the patient 14 .
In these learning scenarios, there is a variety of simulators that must be seen as complementary tools since they provide the training and accelerate the learning curve of practical surgical skills, enabling a better use in further contact with patients; this contact represents the cornerstone of medical teaching 4 .
The available simulators vary with regard to the level of fidelity (realism) when compared with a live human 4 .The higher fidelity models, such as human cadavers, discarded surgical specimens in surgical procedures, postmortem and live animals, and virtual reality simulators, are more attractive to the trainees 4 .
However, during the training of surgical skills with beginner students, it was demonstrated that the transfer of skills to the clinical environment is independent of fidelity 15 .Thus, low-fidelity models can reduce costs and provide more material and training opportunities without jeopardizing the results 12,15 .
Because of the ethical/legal problems, the financial impact and the access difficulties inherent to training on human cadavers, live laboratory animals and virtual reality simulators, numerous bench models have been described as options for the training of surgical techniques 4 .Based on this, the main focus of this study is to propose the use of a bench model made of organic fruits or vegetables as a complementary alternative to teaching and learning; this model is accessible, portable, reproducible and of low cost and it can be used to complement the teaching of the surgery basis during medical education.
Similar organic models, with different indications, were described previously; they were made with oranges to the learning of skills in plastic surgery and debridement of necrotic ulcers, and with bananas, tomatoes and melons for the training of Mohs micrographic surgery and biopsy [16][17][18][19][20] .The bench model and its The training of some surgical techniques could be carried out on models such as discarded surgical specimens 22 or postmortem animals 4 .However, for the use of human organs, donation is required by the consent of patients and/or family, and also the existence of a collection/storage service in the institution itself.The postmortem animals need adequate facilities for storage and disposal, which often complicates and impedes training.
There are also risks of infection in both cases (human organs and postmortem animal).
Nevertheless, the proposed bench model should not necessarily replace the teaching simulators used in different educational institutions.Indeed, the proposal is that it is complementary or adapted to the existing teaching.Some fruits (lemon, orange and banana), besides the three-dimensional spatial concept, allow students to have an idea of different layers and, even though being of low fidelity, they can mimic human skin -for example, the colored surface of peel may represent the epidermis, the white portion below may be similar to the subcutaneous cellular tissue and the fruit pulp can be compared to muscles.
Recently, a combination of self-directed training with feedback was described as the most effective method to teach basic technical skills, distributed intermittently over a pre-determined period (weeks) 11 .In training, feedback can be immediate (during training) and/or later (after training) and it is associated with better and faster learning, and also with a greater store up of knowledge over time 9 .In order to obtain an even longer store up and a larger transfer of competences, it is preferable the interspersed practice with periods of rest, in contrast to the single exposure to the method 23 .
Some limitations to this form of teaching (several days or weeks) would be: the higher financial costs, the shortage of faculty experts 8 and the available time of faculty experts 11,24 .One way to reduce costs would be the adoption of bench models such as the organic model proposed here.This model can be reused if stored in proper cooling conditions.
The practice outside the classroom, at home, can reduce the length of supervised training, while the feedback from the instructor would be just on the procedures already performed (e.g., sutures and incisions), reducing the time of supervision; for this, it is necessary that students have learned, initially under the direct supervision of the instructor.The comments generated by computers could also be an option; however, the retention of skills over time is significantly larger when learned through direct feedback from an instructor 8 .The incorporation of trained students 25,26 and of trained nonsurgeon skills coaches 14 could also reduce the time spent by faculty instructors in the teaching of basic surgical skills.So, faculty surgeon would focus on teaching complex tasks and cognitive aspects of clinical training (decision making), that are not duties of the nonphysician skills coach 14 neither to trained students 27 .
In the teaching of surgical skills, the objective assessment is an important component, it is essential for evaluating the performance and evolution of the acquired skills and to provide feedback on training 12,28 ; and it helps to identify whether the proposed fundamentals have been learned by the student 7 .The student can attend the next stage of training since the predefined evaluation criteria are met 12 .If it does not happen, another step in the teaching-learning should be held and a new evaluation should be carried out 7 .
Currently, the Objective Structured Assessment of Technical Skills 6 is the gold standard for this evaluation 28 ,and it consists of a Global Rating Scale and a Task-Specific Checklist 6 .
The Global Rating Scale adopted as an evaluation tool in this study is used to assess the generic aspects of technical performance and it has wide applicability without the need to develop specific lists for each procedure 7 .
The present proposal is structured only in the development of some skills and surgical tasks, it does not meet all the needs of students in training and it should include the acquisition of other skills (dissections, ligating structures, anastomosis and other) 11 that can also be trained in simulation environments 24 .

Conclusion
The bench model made with fruits and/or vegetables, being simple, versatile, portable, reproducible, affordable, easy to purchase, and of low cost, is an option for supplementing the existing simulators for teaching and learning; it is aimed at preparing medical students before they can apply the surgical techniques in daily professional practice.
the learned technique.The purpose of this model is based on the teaching during several training sessions (days or weeks), interspersed with periods of rest, which can be adapted and distributed in a way that complements the curriculum already established and that can be applied in the context of the disciplines of operative technique, clinical surgery, plastic surgery, and others.In classrooms, a group of four students should train under the direct supervision of an instructor (according to previously described by Dubrowski and MacRae 5 ) and they should be encouraged to practice and refine skills at home, later bringing the model with the performed procedures for evaluation with feedback.Instructors can be faculty physicians or nonphysicians, such as laboratory technicians, surgical technicians or students who can master the technique (monitoring format); these nonphysician surgical skills coaches should be trained by a faculty surgeon to administer teaching and practice sessions.It is important to set teaching goals in an increasing order of difficulty, which must be distributed at the sessions.The basic structure of each session is a brief talk with pictures and videos-classes on the proposals of the day, followed by training.Additional explanations can be made during practice.Initially, the procedures can be demonstrated by the instructors to the student group.After that, specific points of the techniques can be addressed individually.

For
the chosen fruit (or vegetable) not sip during training, it should be fixed in the Styrofoam with needles.It is also needed No. 15 blade and No. 3 scalpel cable, anatomic and tooth rat tweezers, Mayo scissors, needled threads and Mayo-Hegar needle holder (Figure 1).

FIGURE 1 -
FIGURE 1 -Organic bench model and materials required for the teaching and learning on basic surgical skills.
injury and using the taught technique.Then, sutures are made to close the edges of the incised area, also applying the teachings about the technique.Different incisions (linear, circular, vertical and horizontal) and sutures (single interrupted sutures, vertical mattress suture according to Donati and McMillen, modified vertical mattress suture according to Allgöwer, horizontal mattress suture, running simple suture and running locked suture) (Figure 2) can be trained.

FIGURE 2 -
FIGURE 2 -Organic model for the learning on different techniques of incisions and sutures.(A-B) Elliptic and circular pattern.(C) Single interrupted suture and (D) running simple suture.Besides the correct way to handle instruments (scalpel, tweezers and needle) are important to teaching about the placement of the scalpel in relation to "skin"(relationship of the angles), the proper way to perform the incision (e.g., no movements of "aliasing" and no movement sideways), and carrying out the sutures (e.g., spacing of stitches and coaptation of the "edges").

FIGURE 3 -
FIGURE 3 -Organic model for the training of basic surgical techniques.(A)Simulation of a "skin tumor" and (B) of its surgical resection.The "skin tumor" should be resected intact with full excision of thickness of peel fruit.This surgical procedure must be careful to avoid that the rind of the fruit becomes excessively damaged and/or torn.
form of use in this study provide the teaching-learning for beginners in surgical techniques training and, as students acquire the pre-set requirements (simple skills), training can be enhanced with the teaching of more complex procedures in the model itself or in other simulators.Backstage models and latex gloves are also reproducible, they are readily available and are inexpensive; therefore, they do not allow the training of procedures such as excisions and three-dimensional reconstructions.Synthetic materials such as polyurethane 21 (Allevyn ® ), microfoam tape 7 (3M ® ) and latex skin pad 7 (Limbs & Things ® ) enable the training of these procedures; however, not in three-dimensional plane and they are difficult to acquire compared to vegetables and fruits.