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Development and Validation of a Low-fidelity Simulator to Suture a Laparotomy in Rabbits

Juan J. Pérez-Rivero, Tonantzin Batalla-Vera and Emilio Rendón-Franco

An easily constructed, low-cost simulator
is assessed for its efficacy in the surgical training
of veterinary science undergraduates

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Introduction

There is a growing need for the development of alternatives to reduce, replace and refine  the use of animals for surgical training in contemporary veterinary education at the undergraduate level. In the present study, a simulator to suture a midline laparotomy in the rabbit was designed, that could be constructed from widely-available and low-cost materials. The simulator was used to develop surgical skills in students at the undergraduate level of veterinary medicine. Thirty-five, third-year veterinary students, with no previous surgical experience, were divided into two groups: a control group that did not use the simulator (n = 19), and an experimental group that used the simulator three times to practise the suturing of a laparotomy (n = 16). Later, both groups performed
a midline laparotomy in an anaesthetised rabbit, and the rate of closure of each anatomical plane (peritoneum, additional reinforcement, and skin) was measured.

The usefulness of simulators

The surgical training of undergraduate students by using live animals provides few opportunities for real training and is applicable only to certain surgical techniques. In addition, it also raises serious ethical and animal welfare considerations. The students themselves are also subjected to a level of stress, this being, in most cases, a cause of errors. Consequently, they do not adequately benefit from the training provided.1,2

In veterinary medicine and animal sciences, the Three Rs principles are being implemented as widely as possible. This involves the reduction, replacement and refinement of animal use, both in experiments and in teaching.3 One way to accomplish this is through the use of various simulators in their different forms, such as synthetic simulators, multimedia simulations, virtual reality, carcasses, and ethically sourced animal tissues.4,5 These provide training alternatives, which permit the acquisition of skills to successfully meet the needs of future clinical and surgical experiences with live patients, and to ensure that maximum educational value is achieved during practical training.6

The fidelity of a simulator is determined by how much realism is provided through characteristics such as visual cues, touch, the ability to feedback, and interaction with the student. In general, simulators can be divided into two groups: high-fidelity simulators, which are usually highly technical, detailed and realistic; and low-fidelity simulators, which have a low level of realism, are usually made with widely available and low-cost materials, are often portable, and can be used on a table. Despite their simplicity, the latter group of simulators assist the development of psychomotor skills.7 Some limitations of the use of simulators are related to their cost or difficulty in sourcing spare parts. Moreover, despite the large number of simulators that have been developed, few studies have been conducted to evaluate their effectiveness, leaving the concept of teaching through simulators at an empirical stage.8 Therefore, it is necessary to develop inexpensive, easy-to-construct simulators that support the process of surgical teaching, and also to quantitatively assess the effectiveness of their use. Therefore, the aim of this work was to develop and validate a low-fidelity simulator to assist in the teaching of the correct technique for closing a rabbit midline laparotomy.
Simulator assembly

Development of the simulator

A 10cm long and 4cm wide opening was made in an empty plastic 500ml solution bottle (Pisa Agropecuaria, Guadalajara, Jalisco, Mexico), leaving protruding areas to represent both the xiphoid process and the pubic symphysis (Figure 1a). To give support to the bottle, an internal  cardboard lining was added, as well as three 3ml syringes widthwise (Figure 1b). Two 3mm thick silicone sheets were made by pouring 270ml of PE53® silicone rubber (Poliformas Plasticas, Mexico City, Mexico) into a mould, 23cm long by 13cm wide, which was allowed to set at room temperature for 24 hours.

The back-board from a standard paper clipboard was used as the simulator base, with the plastic bottle placed onto the board and the first sheet of silicone overlaid, in order to simulate the peritoneum (Figure 1c). Subsequently, the rectus abdominis muscles were simulated by placing two sheets of 3mm thick × 28cm long × 21cm wide polypropylene around the bottle (Foamy; Mylin, Mexico City, Mexico), leaving a gap of 3cm in width along the entire midline. Finally, this layer was covered with the second sheet of silicone to simulate skin, and both sheets of silicone were tightened onto the clipboard base with paper clips (Figure 2a). The appropriate size head, thorax and abdominal organs were fashioned from cotton fabric and added to the simulator prior to use (Figure 2a).
General view

Simulator validation

Thirty-five students in the third year of a veterinary medicine and zootechnics course at the Universidad Autónoma Metropolitana, Unidad Xochimilco, with no previous experience in surgery, received a 120-minute theory session, supported with slides, on the midline laparotomy technique and suture in rabbits.9 This was part of the Surgical-Veterinary Therapeutic Bases module. Later, the students were divided into two groups: the experimental group (n = 16), which  was organised in four surgical teams of four participants each, and the control group (n = 19), which was divided in four groups of four participants and one three-participant group. Each student was assigned his/her rotation within the group, in such a way that they all covered all the roles once (surgeon, first assistant, scrub nurse, and anaesthesiologist). Each surgeon/first assistant team (according to the assigned rotation) of the experimental group used the laparotomy simulator two days prior to the practice on the live animals. They were asked to repeat three times the following procedure: put the surgical drapes in place (Figure 2b); perform a 7cm incision, including all the layers of the simulator; suture, with continuous stitches, the first silicone layer (peritoneum), which was reinforced with inverted ‘U’ stitches; and suture, with Sarnoff stitches, the second silicone layer (skin). The first assistant was only allowed to help the surgeon in handling the surgical instruments that were used. The closure of planes was performed by using nylon 2-0 suture (Figure 3).
Simulator in use

Subsequently, the participants of both groups performed midline laparotomies on 35 clinically healthy New Zealand rabbits (Oryctolagus cuniculus), suturing midline (peritoneum) with continuous stitching, reinforcing (muscular fascia) with inverted ‘U’ stitches, and suturing the skin with Sarnoff stitches, all performed under general anesthesia, according to the method previously described by Perez-Rivero and Rendón-Franco.10 Both the control group and the experimental group performed one surgery weekly. In total, evaluations were completed in 4 weeks (i.e. one week for each participant from each team).

Since the lengths of the incisions were different in all the cases, the rate of closure of each anatomic plane and all planes in total, was calculated as follows: the length of each incision was measured (in centimetres), and this was divided by the time (in minutes) taken to complete the suturing. The result was expressed in minutes per linear centimetre of incision (MLCI). During the whole process, each group was supervised by two professors and five assistant instructors.
Table 1

Statistical Analysis

Students having the prior role of first assistant, scrub nurse, and/or anaesthesiologist, would have previously observed and/or helped in the performance of the laparotomy. This could have resulted in an improvement in their performance when participating as actual surgeons. To rule out these effects, total MLCI values were compared among the members of each group, according to whether they acted as the surgeon in week 1, 2, 3 or 4, to ascertain whether there was a significant difference in their surgical proficiency, by using the one-way ANOVA with a significant value p < 0.05.

Once the effects of previous observation and/or assistance were ruled out, the MLCI values of each individual anatomical plane and the totals were compared between the control and the experimental groups, by means of the ANOVA test (significant value p < 0.05). All tests were performed by using the PAST® program.11

Ethical and animal welfare considerations

The present protocol was approved by the Comité Interno para el Cuidado y Uso de los Animales de Laboratorio (Internal Committee for the Welfare and Use of Laboratory Animals) from the Universidad Autónoma Metropolitana Unidad Xochimilco, with
reference number DCBS.CICUAL.02.10.

Results of simulator use

Comparisons of the proficiency of group members according to the week in which they acted the role of surgeon did not show a difference (p > 0.05), supporting the idea that observation and/or assistance did not improve technique. When comparing the MLCI values of each plane as well as total MLCI values between the control group and the experimental group, all were different (p < 0.05) with a higher rate of closure for the experimental group. The MLCI values of each group, as well as their comparisons, are shown in Table 1.

The experimental group performed the three planes of laparotomy suture in 5.34 ± 1.63 minutes per linear centimetre of incision (MLCI), compared to the control group that performed it in 7.03 ± 1.77 MLCI. This difference was significant (one-way ANOVA; p < 0.05) and showed that repeating the procedure three times with the simulator improved
suturing skills in a laparotomy.

 

Discussion

When comparing MLCI values among the participants of each group independently, and not presenting differences, it is evident that observing and/or helping during the procedure did not render psychomotor skills or abilities in the participants. The use of complementary strategies, such as the use of the simulator, is necessary for a student to develop manual dexterity and the instrument skills required for the successful application of sutures.1,6

On the other hand, the experimental group demonstrated better suture skills for the laparotomy in rabbits after performing three repetitions of the procedure in the simulator. These findings agree with those reported by Aggarwal,12 who found in his study that laparoscopic surgeons required two repetitions of a particular procedure in a simulator, in order to learn it. The simulator required them to hold the tissue, lift it up, place a clip, and then cut; for trainees, seven repetitions were required to learn to perform the same procedure. However, we have to take into consideration that this particular procedure would have a longer learning curve than performing a suture.

Conclusions

The results make evident the advantages of the use of simulators, when recommended as training devices for undergraduate students. However, these models should be considered as complementary tools in the teaching of surgical procedures, for they help in the acquisition of skills and abilities that lead to better performance in real patients, and eventually reduce the number of training events that require the use of live animals.13

More studies are required to determine the time and number of necessary repetitions in training with these bench simulators, in order to reach an adequate level of proficiency. Further work will also be needed to make the simulators more realistic, and to investigate ways in which to take maximum advantage of this training tool.

Author for correspondence:
Dr Juan J. Pérez-Rivero
Departamento de Producción Agrícola y Animal
Universidad Autónoma Metropolitana Unidad
Xochimilco
Calzada del Hueso 1100
Colonia Villa Quietud
Delegación Coyoacán 04960
Mexico City
Mexico
E-mail: jjperez1_1999@yahoo.com

References

1 Langebæk, R., Eika, B., Jensen, A.L., Tanggaard, L., Toft, N. & Berendt, M. (2012). Anxiety  in veterinary surgical students: A quantitative study. Journal of Veterinary Medical Education 39, 331–340.
2 Smeak, D.D. (2007). Teaching surgery to the veterinary novice: The Ohio State University experience. Journal of Veterinary Medical Education 34, 620–627.
3 Russell, W.M.S. & Burch, R.L. (1959). The Principles of Humane Experimental Technique, 238pp. London, UK: Methuen.
4 Martinsen, S. & Jukes, N. (2005). Towards a humane veterinary education. Journal of Veterinary Medical Education 32, 454–460.
5 Kumar, A.M., Murtaugh, R., Brown, D., Ballas, T., Clancy, E. & Patronek, G. (2001). Client donation program for acquiring dogs and cats to teach veterinary gross anatomy. Journal of Veterinary Medical Education 28, 73–77.
6 Valliyate, M., Robinson, N.G. & Goodman, J.R. (2012). Current concepts in simulation and other alternatives for veterinary education: A review. Veterinarni Medicina 57, 325–337.
7 Perez-Rivero, J.J. & Rendón-Franco, E. (2012). Experience of the use of table-top simulators as alternatives in the primary surgical training of veterinary undergraduate students. ATLA 40, P10–P11.
8 Schout, B.M.A., Hendrickx, A.J.M., Scheele, F., Bemel mans, B.L.H. & Scherpbier, A.J. (2010). Validation and implementation of surgical simulators: A critical
review of present, past, and future. Surgical Endoscopy 24, 536–546.
9 Griffon, D.J., Cronin, P., Kirby, B. & Cottrell, D.F. (2000). Evaluation of a hemostasis model for teaching ovariohysterectomy in veterinary surgery. Veterinary Surgery 29, 309–316.
10 Perez-Rivero, J.J. & Rendón-Franco, E. (2014). Cardiorespiratory evaluation of rabbits (Oryctolagus cuniculus) anesthetized with a combination of tramadol, acepromazine, xylazine and ketamin3. Archivos de Medicina Veterinaria 46, 145–149.
11 Hammer, Ø., Harper, D.A.T. & Ryan, P.D. (2001). PAST: Paleontological statistics software package for education and data analysis. Paleontología Electrónica 4, 1–9.
12 Aggarwal, R., Grantcharov, T.P., Eriksen, J.R., Blirup, D., Kristiansen, V.B., Funch-Jensen, P. & Darzi, A. (2006). An evidence-based virtual reality training program for novice laparoscopic surgeons. Annals of Surgery 244, 310–314.
13 Denadai, R., Oshiiwua, M. & Saad-Hossne, R. (2014). Teaching elliptical excision skills to novice medical students: A randomized controlled study comparing low- and high-fidelity bench models. Indian Journal of Dermatology 59, 169–175.

 

 

Personal Reflections on Veterinary Science Training and the Three Rs

Rosemary Elliott

Students against the thoughtless use of animals
in veterinary education need  support
to be true to their values, to use
science to uphold them, and to never
give up on advocating for the
highest standards of animal welfare

This opinion piece is something I needed to write personally, and it shocks me to notice the ten years that have passed since I enrolled as a mature-age student in veterinary science. It was a privilege to have this opportunity, and I am grateful that I can now advocate for animals in a way I never could have done before, particularly through my work with Sentient. By the time I enrolled in veterinary science, the faculty where I studied had made huge advances in the ethical use of animals in teaching, most notably through the banning of ‘terminal surgeries’. Since my time as a student, things have improved even more, and the faculty is leading the way in developing a national curriculum for animal welfare and ethics in veterinary teaching. Yet, despite this, some attitudes and practices ‘die hard’, and many of my experiences could only be described as vicarious trauma — hence the passing of so much time before I felt ready to give life to them with words.

Although the animals I speak of were used primarily for educational purposes, I do hope that those of you working in the laboratory setting with research animals, will find that my reflections will stimulate your own thinking and resonate with some of your experiences. We have much in common in our struggle to do our work and to do the best we can by the animals in our care.

Anatomy classes

Admittedly, I grew up with an idealised view of veterinary practice, starting with Dr Doolittle as a very small child, then moving on to All Creatures Great and Small and the other James Herriot books. Although 60 years had passed since the setting of those stories, with the onset of intensive farming, I went on assuming it was primarily about supportive teamwork and above all, empathy for animals.

The first wake-up call came in the form of Anatomy 1A. The laboratory, a huge room with grimacing dead greyhounds lying on metal trays, became a hothouse of anxieties, sometimes played out by the larking about that involved the throwing of body parts. The smell of formalin was so powerful that I can still conjure it up. In groups of three or four, we learned anatomy the traditional way, which some of us described as “being thrown a dead dog and a textbook”. There was minimal instruction, so we were left to hack away in the pursuit of identifying a lengthy page of anatomical features, ‘all examinable’, with the pressure to clean up before our class ended.

I don’t remember being told why they were always greyhounds, or how they were sourced. There was certainly no time for debriefing, and we learned early on that it was unacceptable to appear emotional. I soon became desensitised to this horrible scene until the 4th year, when I was initiated into surgical training on freshly-killed pound dogs of various breeds — soft and floppy and somehow, not being greyhounds, they seemed more individual, more like pets. I remember struggling with sad moments of wondering about their lives and whether they had been loved, and feeling ashamed of my tacit acceptance of greyhounds as production animals.

Now, this raises for me the question of respect for life, even after a life is over. If we are serious about honouring the dignity of animals and safeguarding their welfare, veterinary training must provide as many opportunities as possible for effective learning that reduces the number of animals used, such as initial skills training through videos and silicone simulator anatomical models. At Sentient, we also call for the veterinary profession to supply cadavers from ethical sources, rather than colluding with the widespread disposal of racing greyhounds by ‘convenience euthanasia’.

Practical animal husbandry training

Chickens and eggs
The Animal Husbandry practical classes on production animals were another shock. I expected state-of-the-art facilities for the animals, but the picnic atmosphere was killed for me by the sight of housing systems more typical of factory farming. The laying hens were all kept in battery cages, rows of little prisons with no natural lighting. Questioning this was frowned upon — we were there to show our enthusiasm and tick the boxes for the mastery of required skills. I was told these were working farms, the message to first year students from some staff members being that animal welfare is, by default, secondary to industry profit.

One of my saddest memories was being tested on my ability to remove a hen from a battery cage, restrain and examine her, then to return her to the cage, head first. She flapped with gusto and resisted going back inside. I felt I had performed an act of cruelty, giving her a tiny taste of what her body could do, but perhaps never would again. Then there was the class where chicks were deliberately infected with coccidiosis, so that we could observe the characteristic droppings. And the class on egg production, where the tutor smilingly broke fertilised eggs — to prove what, I don’t understand anymore — but leaving me with the image of an embryonic bird with a throbbing heartbeat, destined for the sink.

Compassion for birds was a disadvantage in veterinary training, where speciesism was very much alive and well. Most student complaints about animal treatment focused on mammals. In the 4th year, we were taught to euthanase chickens humanely, but were given needles of the wrong gauge, which caused their wing veins to blow. I felt murderous at the sight of students who laughingly persisted, while the ‘spent’ hens blinked helplessly as they were repeatedly traumatised by needles that failed to bring an end to their joyless lives. The demonstrator did not intervene. I learned nothing useful from this class — because after observing the other students, I decided not to even try. When I complained, the response was that they had run out of the correct-sized needles and would replace them at the next class, as if the problem had been purely a practical one.

This class could have formed a foundation for trainee veterinarians in the careful preparation and respect for birds during euthanasia. Instead, it reinforced the view of chickens as somehow less sentient, due to their status as production animals. We must consider how invoking the Three Rs would have helped here. Perhaps by the initial replacement of live birds by video footage of how to correctly perform euthanasia? But when it came to the use of live birds, which was essential, what was needed was a commitment by staff to the humane treatment of animals, and an expectation that students would demonstrate this attitude through their own behaviour. Instead, the atmosphere was cavalier and callous, and not at all conducive to any form of refinement.

Tail-biting management classes
The university’s pig farm was another indictment, with sows in sow stalls, and non-breeding pigs in dark little pens where we practised catching them with snares. This was the scene of my own most shameful memory, where, despite my opposition to unnecessary invasive procedures, I performed teeth-cutting, tail-docking and ear-notching on a piglet. I remember feeling terrified at the thought of this practical class, because of the expectation to ‘do as farmers do’ — which was ostensibly to improve the welfare of the piglets by preventing tail biting. I was unaware of any conscientious objection policy at that stage of my training. So I stalled for time, trying to look useful without actually doing anything, until the tutor presented me with my own piglet and a pair of what looked like pliers. He was clearly annoyed by my questions and my need for reassurance about avoiding the ear vein or how to create the least degree of trauma — a ridiculous question, in view of the fact that there was no analgesia.

I will always remember holding this warm, pink little being with the racing heart, who I just wanted to protect, but instead, I brutalised him. I try to cope with this memory by knowing that I worked as quickly as I could, and then rubbed his body all over to distract him from the pain, as I carried him back to his mother and made sure he found a teat to suckle on. I also try to cope by using this as the basis for my commitment from that day onwards to never again perform such an atrocity. But I will never forget standing there, praying the pain would soon end. I will never forget being inconsolable for days. I still cry at the memory of what I did. I betrayed my own values out of fear of failure and not being confident enough to stand up to pressure, aided by false reassurances that I was doing the right thing.

That night, I researched teeth cutting, and found a recent article in a veterinary journal that documented how the procedure predisposes to injury and infection in the mouth and gums. I have since visited free-range pig farms, where the ‘cannibalism’ we were indoctrinated with was not an issue. All these pigs kept their tails, and their baby teeth. I had been fed a lie, pressured into performing unnecessary and inhumane procedures on a piglet that would never be allowed on a puppy. And I was an educated adult, who had already considered these welfare issues and was not relying on this to earn a living.

My pathetic attempt at reduction, by limiting my actions to one piglet, did nothing to safeguard the welfare of that individual. Like so much of what we were expected to do in veterinary training, it simply should not have been allowed, because the procedure itself was unethical. In such cases, I believe we can be guided by the Three Rs to give priority to replacement, by showing students a video of these procedures, not least so that they know what to expect on farm visits. This can go hand-in-hand with advice about how these practices can be avoided through less-intensive husbandry practices. When invasive procedures are required, the focus should then be on initial video or simulator learning, to reduce the number of animals used, followed by refinement — i.e. teaching students to always use anaesthesia and/or analgesia to minimise stress and suffering.

Other lessons
There were multiple instances, where students at the university farm were expected to perform unnecessary invasive procedures on production animals as part of their learning experience, with routine farming practices cited as the ‘gold standard’. My question was always this: Why are we following the ways of the farmers, rather than offering something more as potential veterinarians? But most students, particularly those from rural backgrounds, accepted the status quo, citing the need for ‘real-world’ practice. It was also regarded as essential preparation for extramural farm placements, which brought further horrors that I will not elaborate on here. Common sights during my training were cattle being dehorned without analgesia, in some instances leading to maggot-infested wounds; the repeated attempts to lasso a terrified cow on a hot summer’s day, which led to her jumping a fence and almost breaking her hip; exsanguination of a sheep to prove the procedure is humane; and tail-docking and castration of lambs, who were pinned down on their backs in a ‘cradle’, all without analgesia, while students delayed the procedure by joking about who would remove which testicle.

Promotion of the Three Rs and alternatives
My reason for writing this, apart from my own need to debrief and reflect, is to think about the context that must be created, if the Three Rs are to be of use in veterinary education. Adherence to the Three Rs will only come about within a culture of empathy and respect for animals, which should also be extended to students. Offering a transparent conscientious objection policy, and reinforcing in every unit of study that there are alternatives to ethically-contentious procedures, is a crucial part of this. The way I coped was to find like-minded students, involve myself in the student-run animal welfare association, use the conscientious objection policy and formal avenues within the faculty to lodge complaints, and seek the support of staff members. And I will always be grateful to several academics, who were wonderful role models on how to uphold ethics in teaching, who had witnessed and objected to far worse in their own veterinary education, and who encouraged me and my fellow students to be true to our values, to use science to uphold them, and to never give up on advocating for the highest standards of animal welfare.

E-mail: rosemary.elliott@sentient.org.au