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Volume 21, Number 1 Spring, 1994

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Integrating Alternative Models into the Existing Surgical Curriculum

C. L. Greenfield, A. L. Johnson, C. W. Smith, S. M. Marretta, J. A. Farmer and L. Klippert
From the Department of Veterinary Clinical Medicine (Greenfield, Johnson, Smith, Manfra Marretta, Klippert)
and the Department of Administration, Continuing, and Higher Education (Farmer),
University of Illinois, Urbana, IL 61801.


Introduction

Historically, surgery was taught to veterinary and medical students through the use of live animals on which multiple surgical procedures were taught over one or more successive weeks. As humane care of laboratory animals became a more important issue, many institutions moved away from this practice. Currently, some veterinary schools conduct surgery laboratories where the animal survives one or more minor procedures and is euthanized at the termination of a major surgical procedure. Other institutions teach surgery to veterinary students without survival surgery laboratories (1).

Use of live animals for veterinary surgical education has come under scrutiny by many people, including animal rights organizations, veterinary students, and veterinary surgical educators. Concerns include the large number of animals which are euthanatized yearly for this purpose, the need to use these animals for this purpose, and the cost of purchasing and housing these animals. The current trend is to decrease or eliminate unnecessary or excessive use of live animals for teaching purposes and replace the live animal use with alternatives. An alternative is acceptable for teaching if it allows the student to reach at least the same level of proficiency as obtained when the same procedure is taught in a traditional manner. Ideally, this level of proficiency is also adequate for the student to practice clinically after graduation from veterinary school.

Alternatives Used in Surgery Labs at The University of Illinois

At The University of Illinois, we have made humane issues a priority in our surgical teaching program and we have taken a pro-active attitude. We have tried to alter our program of surgical education to meet the needs and desires of the veterinary students, society and the surgical educators. While changing our laboratory curriculum we have also tried to maintain the goal of providing the best surgical education possible. We have not had any students who have requested participation in an alternative program instead of our regular surgery course even though an alternative program is in existence at our institution. We feel that the incorporation of alternatives into our standard teaching program and the decreased use of live animals in surgery laboratories may be partially responsible for student acceptance of our program.

Many changes were made in our small animal surgery laboratories over the past 10 years. The initial change, which occurred in the early 1980s, was from multiple survival procedures on one animal to one survival procedure per animal. The single survival laboratories were set up so that one procedure was performed on an animal, followed by one week of survival, a more invasive surgery was then performed and the animal was humanely euthanatized at the end of the second laboratory (Table 1).


Table 1. Surgery Laboratories: 1985-1986. (S = survival, NS = nonsurvival)

Laboratories ---- Animals

Gowning, gloving, patient preparation, incisions ---- S
Exploratory laparotomy ---- NS
Gastrotomy, cystotomy ---- S
Enterotomy, intestinal resection/anastomosis ---- NS
Ophthalmic surgery ---- NS
Cystotomy, ovariohysterectomy ---- S
Thoracotomy ---- NS
Cervical disc fenestration ---- S
Approach to hip and pelvis ---- NS
Approach to humerus and elbow ---- S


During the 1988 to 1989 school year, the surgery laboratory curriculum was revised to emphasize basic techniques and skills (Table 2). The introductory laboratories on aseptic technique, gowning, gloving, etc., which had previously been taught separately in large and small animal surgery courses, were combined. Additionally, alternatives to live animal use were introduced where appropriate. One of the first alternatives that was incorporated into the laboratory was the use of purchased slaughtered chickens as a model for suturing on tissues instead of using live, anesthetized dogs for skin incision and suturing instruction. Suturing on chickens allowed the students to begin to get the feel of suturing in tissues without the use of live animals. It also allowed students to begin to develop good tissue handling skills and manual dexterity and proficiency. We feel that the learning experience gained from the suturing practice on purchased chickens is so beneficial that it remains a part of our surgery laboratory program.

Also added in the 1988-1989 year was a laboratory using bones harvested at a previous terminal laboratory as an introduction to fracture repair (Table 2). The bones were used to teach proper techniques for placement of pins and wires, for teaching principles of fracture repair, and for practice of repair of specific types of fractures. Additionally, plastic bones made by Sawbones(R) were used for laboratories when harvested bones were not available and for models of pathologic conditions (2, 3). The success of these bone models for the instruction of orthopedic principles and techniques in psychomotor laboratory settings has been documented (2-4).


Table 2. Surgery Laboratories: 1988-1989. (NA = no animals used, S = survival, NS = nonsurvival)

Laboratories ---- Animals

Scrubbing, gowning, gloving, patient preparation ---- NA
Draping, instrument handling, packs, sterilization ---- NA
Incisions, hemostasis, ligation, suturing, knot tying ---- Chickens
Exploratory laparotomy ---- S
Splenectomy, gastrotomy ---- NS
Enterotomy, intestinal resection/anastomosis ---- NS
Thoracotomy ---- NS
Ovariohysterectomy, cystotomy ---- S
Salivary gland surgery, lateral ear canal resection ---- NS
Approach to humerus and elbow ---- S
Approach to stifle ---- NS
Introduction to fracture repair ---- Bones


In 1989-1990, the laboratories were revised to place more emphasis on procedures that are commonly performed in small animal practice (Table 3). Less frequently performed procedures were no longer taught and more emphasis was placed on neutering procedures, declaws, and basic orthopedic procedures and techniques. The total number of laboratory periods remained unchanged. A new program was instituted in the small animal surgery laboratories. A neutering program with a local humane shelter was developed in which adoptable dogs and cats were brought to our facility for neutering. Prior to surgery, all animals received a complete physical examination, fecal examination for intestinal parasites, and the routine preoperative blood work for young healthy animals (including a packed cell volume, total protein, and blood urea nitrogen determinations). All dogs were heartworm tested, and all cats were feline leukemia tested. Animals with abnormalities were treated appropriately. Elective neutering procedures (ovariohysterectomy or castration), and declaw (when requested on selected cats), were performed by the junior veterinary students in the surgery laboratory. All animals were kept in the hospital for observation and postoperative care by the student surgeons for 3 days to 1 week after completion of the surgery. The animals were examined by the students twice daily and a faculty member at least once daily during the postoperative hospitalization period. The students treated postoperative complications which developed.

The humane shelter program has been very well received by the students. They like the exposure to the elective procedures that they need to be competent in upon graduation; they are happy about being able to provide this service to the community; and they feel that following survival surgeries has been beneficial. An additional positive note is that the humane shelter adopts more animals when they have already been neutered. This program has been so successful that we are currently working with a second humane shelter.


Table 3. Surgery Laboratories: 1989-1990. (NA = no animals, S = survival
NS = nonsurvival, S-HS = survival, humane shelter animals)

Laboratories ---- Animals
Scrubbing, gowning, gloving, patient preparation ---- NA
Draping, instrument handling, packs, sterilization ---- NA
Incisions, hemostasis, ligation, suturing, knot tying ---- Chickens
Splenectomy ---- S
Ophthalmic surgery ---- NS
Enterotomy, intestinal resection/anastomosis ---- NS
Ovariohysterectomy x 3 ---- S-HS
Castration (canine and feline)/declaw ---- S-HS
Approach to stifle and humerus ---- NS
Introduction to fracture repair ---- Bones


The addition of the humane shelter neutering program into our junior surgery laboratory schedule has also provided an economic advantage over purchasing dogs for use in the laboratory. The cost of purchasing and housing a dog for one nonsurvival surgery at our institution is approximately $175. The costs incurred for neutering a dog from the humane shelter is approximately $50 and varies slightly depending on how many days the animal stays hospitalized postoperatively.

The elective neutering program has also been incorporated into our 4th-year clinical rotations. When time permits, senior veterinary students perform these procedures to gain extra surgical experience and to become more competent. Additionally, new interns perform elective neutering surgeries on the humane shelter animals early in their internship year to gain experience before instructing the students.


Table 4. Surgery Laboratories: 1991-1992. (NA = no animals, NS = nonsurvival, S-HS = survival, humane shelter animals)

Laboratories ---- Animals
Scrubbing, gowning, gloving, patient preparation ---- NA
Draping, instrument handling, packs, sterilization ---- NA
Incisions, hemostasis, ligation, suturing, knot tying ---- Chickens
Splenectomy ---- NS
Enterotomy, intestinal resection/anastomosis ---- NS
Cystotomy/gastrotomy ---- NS
Ophthalmic surgery ---- Cadavers
Oral surgery, dentistry ---- Cadavers
Approach to stifle ---- Cadavers
Ovariohysterectomy x 2 ---- S-HS
Castration (canine and feline)/declaw ---- S-HS
Introduction to fracture repair ---- Bones


In 1991-1992, two existing laboratories were changed to the use of cadavers (Table 4). These were the ophthalmic surgical laboratory and the laboratory for the approach to the stifle. For the stifle laboratory, legs harvested at previous terminal surgery laboratories were frozen. Prior to the laboratory, the legs were thawed and were used for instruction of approaches to the stifle joint and for performing certain surgical procedures such as surgical correction of patellar luxation and cranial cruciate ligament rupture. We have found this to be satisfactory.

A dentistry and oral surgery laboratory using cadavers was added to the core small animal surgery curriculum in 1991-1992. Jaws with associated soft tissues were harvested from animals euthanatized at a previous terminal laboratory. The jaws were hemisected and frozen until the day that they were to be used. Students worked in pairs on the thawed jaws. Procedures which were performed included oral examination and dental charting, radiography, scaling and polishing, simple, multi-rooted, and complicated surgical extractions, and oronasal fistula repair. This laboratory fulfilled the need for training students in dental prophylaxis and routine procedures, and has also been very well received by the students.

Our current small animal surgical laboratory schedule is the same as the 1991-1992 schedule (Table 4). It consists of 2 laboratories covering the essentials of aseptic technique, patient preparation, and instrument handling. There are 5 laboratories using alternatives (1 with chickens, 1 with bones, and 3 with cadavers). There are 3 nonsurvival laboratories which involve laparotomies which allows each student to perform one approach and abdominal procedure on an animal that is euthanized prior to performing a survival abdominal procedure. Finally, there are 3 survival neutering laboratories using humane shelter animals which are returned for adoption. These laboratories allow each student to be primary surgeon once on a survival procedure; to observe the outcome of the procedure; and to practice appropriate postoperative care prior to being responsible for client animals in the 4th-year surgery rotations.

During the past 3 years, we have developed a set of realistic soft tissue models (5). The initial models that were developed were canine spleen, kidneys, and liver, followed by canine stomach, gall bladder, pancreas, small and large intestine, urinary bladder, and uterus. Additionally a canine body cavity model was made. The next step in the transition of our teaching laboratory is to incorporate the use of soft tissue models into the laboratory. Student performance on the models and teaching effectiveness of the models in the laboratory setting will be evaluated. Student surgical performance will be evaluated in the clinical year to determine if learning on these models is acceptable. A trial laboratory using models was conducted in 1992-1993. Results from this study are still being analyzed. If the results indicate that the soft tissue models are successful tools for teaching surgery, it is our hope to replace the nonsurvival laboratories currently in our curriculum with laboratories using soft tissue models by the 1993-1994 year.

Survey of Veterinary Students Regarding Surgery Laboratories

Students were surveyed yearly at the end of the small animal surgical laboratories about the use of live animals and alternatives in the teaching laboratories and to monitor student acceptance of models as teaching tools. The questions asked were: 1) What are your feelings concerning the use of live dogs for learning surgical principles and procedures in the laboratory? 2) What are your feelings concerning survival surgeries in the laboratory? 3) What are your feelings concerning the use of appropriate alternatives (models, others species, cadavers) for learning surgical principles and procedures in the laboratory? Answers to survey questions were rated on a scale of 0 to 5, with 0 being very negative and 5 being very positive. Comments about the laboratory experience and the use of models were also solicited.

Mean scores (± SD) of student responses to the survey questions from 1986-1989, and 1991-1992 years were calculated. Mean values of student responses between the different survey years were compared using the Welch's alternate t test. Mean values were considered to be statistically different if p &#60 0.05.


Table 5. Mean scores (± SD) of student responses to survey at end of small animal surgery laboratories.
		1986-1987 A	1987-1988 B	1988-1989 C	1991-1992 D
No. of 	    33		    65		    85		    36
students	
Question 1	4.08±1.27*	4.47±1.16	4.37±0.85*	4.65±0.63
Question 2	3.50±1.47*,+	4.15±1.31*	4.05±2.35*	4.92±0.28
Question 3	2.23±1.84*,#	2.99±1.77#	3.74±1.37	3.61±1.54

A -	Single survival surgeries followed by euthanasia after second
	procedure, no alternative models in these laboratories.
B -	Laboratory schedule same as 1987 year.
C -	Chicken and bone models incorporated into laboratory, emphasis placed
	on teaching basic techniques.
D -	Ophthalmic surgery and orthopedic procedures changed to be performed
	on cadavers, dental procedures and oral surgery laboratory on cadavers 
	added, chicken and bone models continued, survival neutering procedures 
	on humane shelter animals incorporated into laboratory, no other 
	survival surgeries.
* -	Significant difference when compared to results of same question in
	1991-92.
+ -	Significant difference when compared to results of same question in
	1987-88.
# -	Significant difference when compared to results of same question in
	1988-89.

Students had generally positive feelings about the use of live animals for learning surgical principles and procedures (question 1) with mean scores >4 during each year of the survey (Table 5). There were statistically significant elevations of the mean scores for question 1 when the 1986-1987 and the 1988-1989 years were compared to the survey results of the 1991-1992 year. Changes in the curriculum which may have influenced these survey results included the addition of the humane shelter neutering program, decreased use of live animals for other laboratories and the increased use of alternative models over this time period. More appropriate use of live animals in the teaching laboratories appears to have made the students' live-animal surgical experience more positive. Comments about question 1 from all years reflected a strong feeling that some live-animal experience was necessary to learn surgery and that live-animal surgical experience could not be completely replaced by models. In the 1992 surveys, the issue of unnecessary use of animals in teaching laboratories became apparent. Many students commented that live-animal surgeries were necessary and important, but that acceptable alternatives (such as the cadavers used in the dental and the ophthalmic laboratories, and harvested bones and legs for orthopedic procedures) should be used whenever appropriate. Comments such as these were only sporadic in the surveys from earlier years.

The responses to question 2 indicated an overall increase in the acceptance of survival surgeries in the laboratory during the survey period (Table 5). Survival humane shelter neutering procedures were added to the laboratories and all other survival laboratories were eliminated between the first three years and the last year of the survey. There were significant increases in mean scores when the first three years (1986-1987, 1987-1988, and 1988-1989) were each compared with the mean score from the last survey year (1991-1992). Student reaction to the humane shelter neutering program was very favorable. Students felt that neutering of shelter animals was a valuable experience and that they learned by observing their patients during the postoperative period while providing a service for the community. Additionally, the students were pleased with the increased emphasis placed on surgical procedures (elective neutering) which all students felt that they needed to be competent in at the time of graduation. There was also a significant increase in the mean scores of question 2 between the 1986-1987 and the 1987-1988 years which is difficult to explain since the laboratory curricula were the same during these two years.

Prior to incorporating alternative models into the small animal surgery laboratory, many students had negative feelings about substituting models for live animals. Initial responses about the use of appropriate alternatives in the teaching laboratory (question 3) were low (Table 5). After models and alternative teaching methods were incorporated into the laboratories and students were exposed to them (during the 1988-1989 year), student acceptance and mean scores for question 3 significantly increased (between the 1986-1987 and 1988-1989 years; the 1986-1987 and 1991-1992 years; and between the 1987-1988 and 1988-1989 years). Comments about the use of appropriate alternatives in the laboratory have continued to be positive. However, two problems have been repetitively encountered in the response to this question. The first is that the students feel that the models that they have been exposed to are appropriate and acceptable, but that it would be impossible to substitute additional models for other laboratories. The second problem is that every year there have been students who write favorable comments about the models, but who also score 0 or 1 on this question and comment that live-animal surgeries cannot be replaced by alternatives. Based on the survey results and discussions with students, we feel that students react favorably to the alternative models that they have been exposed to, but they are also apprehensive about expressing too much positive sentiment for fear of losing all of their live-animal surgery experience.

Discussion

Several factors affect implementation of alternative methods of teaching. The skills that were previously taught using live animals should be equally or better learned on the alternatives. The objectives of the laboratory and how these objectives will be accomplished on the alternative model should be defined. Clinical relevance of the model and of the techniques and procedures being taught should be established to ensure student acceptance of the alternative method and model.

The use of alternatives to live animals should be presented to the student in a positive fashion and one which justifies the changes. Although there are many students who question the use of animals strictly for learning surgery, there are more who feel that learning on live animals is the only acceptable way. As alternative methods are introduced and the number of live-animal laboratories decreased, it is not uncommon for students to feel that the educators are trying to cheat them out of a valuable learning experience and that they will not be prepared to go into clinical practice after graduation without this live-animal experience.

Advantages of models over the live animal include the availability of models at all times; that all students can perform each procedure (rather than being surgeon, assistant surgeon, or anesthetist as is currently done in live-animal laboratories); and that procedures can be repetitively practiced until an acceptable level of proficiency has been reached. Manual dexterity and surgical proficience can be mastered on the inanimate object without the pressure and anxiety felt during live-animal laboratories. The student who has practiced on models should be better prepared for live-animal surgery. The students must understand that the purpose of teaching on models prior to live animals is to make them better, more competent surgeons when they perform their first live-animal surgeries and that there is no intention on the part of the faculty to replace all live-animal surgery laboratories with laboratories using models.

An essential part of a surgical teaching program such as ours is the incorporation of a neutering program with a humane shelter. The humane shelter program gives the students the necessary exposure to live-animal surgery and patient care prior to work on privately owned animals.

The changes that we have made in our curriculum have involved a gradual integration of alternative models and teaching methods into an established curriculum. The results of our student survey are encouraging and show that our students approve of the changes in our curriculum. Over the course of the survey period responses to all three questions have significantly increased. The high mean scores (>4) for question 1 over all years surveyed indicate that live-animal surgical experience is important to the students. The most positive responses, and significant increases in the mean scores, occurred following the addition of appropriate models and of the humane shelter neutering program. This supports our contention that it is the appropriate use of live animals in the teaching laboratory that is most favorably looked upon by the students.

Mean increases for question 2 on the survey indicate that students feel that survival surgery is a very good learning experience. Additionally, survival surgery is accepted and supported almost unanimously by the students when there is a purpose (neutering animals that will later be adopted) in addition to just practicing a surgery. Responses after incorporation of the humane shelter program were significantly higher than responses addressing other survival surgeries.

Our students also feel that alternative models can be a useful part of a surgical teaching program as evidenced by the responses to question 3. Interestingly, students' opinion of models improved significantly only after they had been exposed to the use of models in a laboratory situation. This confirms our feeling that it is difficult for students to accept new applications of alternative models. However, once they are exposed to new models and have first-hand experience with using a certain model in a learning situation, they are receptive to further use of this model and models in general.

This paper chronicles the evolution of a veterinary surgical teaching program which has progressed from laboratories involving multiple survival surgical procedures to one which uses a minimal number of animals and several alternative models to provide instruction. It also demonstrates the changes in our students' opinions about the use of live animals, survival surgery and alternative models in the teaching laboratory during this period of curricular change. Over the next few years, our surgical laboratory curriculum will continue to evolve to the point of having no nonsurvival surgical laboratories. The elective neutering procedures on humane shelter animals will be used for all instruction of live-animal surgery and postoperative patient care during the 3rd-year surgical laboratories. As our surgical laboratory program continues to evolve, we will continue to monitor student performance during both the 3rd-year teaching laboratories and during the clinical year of training. We will also continue to monitor student acceptance and effectiveness of the alternative models and methods of teaching.

Summary

The surgery laboratory curriculum at The University of Illinois has evolved over the past ten years. Changes were made to address animal welfare concerns as well as the needs of the veterinary students and surgical teaching faculty. Some of the traditionally taught terminal animal laboratories were replaced with appropriate alternative teaching methods. Student response to the use of live animals and alternative teaching models in surgery laboratories has been monitored.

Reference and Endnotes

1. Bauer MS: A survey of the use of live animals, cadavers, inanimate models, and computers in teaching veterinary surgery. Jour of Am Vet Med Assoc 203(7:1047-1051, 1993.

2. DeYoung DJ and Richardson DC: Teaching the principles of internal fixation of fractures with plastic bones. Jour of Vet Med Educ 14(1):30-31, 1987.

3. Johnson AL, Harari J, Lincoln J, et al.: Bone models of pathologic conditions used for teaching veterinary orthopedic surgery. Jour of Vet Med Educ 17(1):13-15, 1990.

4. Johnson AL and Farmer JA: Evaluation of traditional and alternative models in psychomotor laboratories for veterinary surgery. Jour of Vet Med Educ 16(1):11-14, 1989.

5. Greenfield CL, Johnson AL, Arends MW, et al.: Development of parenchymal abdominal organ models for use in teaching veterinary soft tissue surgery. Vet Surgery 22(5):357-362, 1993.


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