Teaching surgery to the veterinary novice: the Ohio State University experience

Surgical training in veterinary medicine has evolved rapidly over the past several decades. Catalysts for change include pressure from concerned students and the public to reduce the use of live animals in teaching; less-than-effective preparation of students for live surgery experience; an overall reduction in faculty time and effort devoted to skills training; college budgetary reallocations mandating reductions in expensive group laboratory experiences; and more specialized case-load patterns in clinical rotations, which have reduced students' exposure to common surgical conditions. In response to these trends, methods for surgery educators to reduce, refine, and replace live animals in surgery training courses at veterinary schools have received broad attention. When these methods are used effectively in a curriculum, it is no longer necessary to sacrifice animals for adequate student training. This article describes a successful and ethical surgical training program used at the Ohio State University College of Veterinary Medicine (OSU-CVM). This program provides early exposure to skills training using surgical simulators and auto-tutorials, ensures that basic skills are mastered before students are exposed to cadaver practice, and requires application of model-based skills to cadavers, with final matriculation to intensive exposure to multiple live-animal procedures via a collaborative surgery program with a local shelter.     

Evaluation of a hemostasis model for teaching ovariohysterectomy in veterinary surgery

OBJECTIVE: To evaluate the efficacy of a reusable plastic model mimicking the anatomy and hemodynamics of the canine female genital tract for teaching basic surgical skills and ovariohysterectomy. SAMPLE POPULATION: 40 veterinary students of the class of 1998. STUDY DESIGN: Prospective study. METHODS: Students'confidence level and experience in private practice was evaluated via questionnaire before training. Students in 2 groups performed an ovariohysterectomy on cadavers (group C, n = 20) or on the model (Group M, n = 20) for 2 hours. Students' psychomotor and basic surgical skills were objectively assessed by the following tests: ligation of a foam cylinder, passing a needle through the eyelets of an electronic suture board, and ligating latex tubing. Results were compared before and after training and within and between groups. The ability of students to perform an ovariohysterectomy in a live dog after training was compared between groups with a scoring system. RESULTS: Students in both groups had similar surgical experience and basic skills before training. The results of the psychomotor and basic surgical skills tests were better in group M after training than group C. The improvement of each student in performing these tasks also increased when students were trained with the model. Scores assigned to students performing an ovariohysterectomy in a live dog were higher in group M (31.45 +/- 1.15) than in group C (20.7 +/- 1.42). CONCLUSION: The model was more effective than cadavers in teaching basic surgical skills and ovariohysterectomy in dogs.     

A Comparison of Surgical Training with Live Anesthetized Dogs and Cadavers

Cadavers were compared with live anesthetized dogs for their effectiveness as models for surgical training of veterinary medical students. One group of students was trained using cadavers, and a peer group was trained using live anesthetized dogs. Both groups then performed an intestinal anastomosis using a live subject. The time to completion of the procedure was recorded. The anastomoses and celiotomy closures were evaluated. Each anastomosis was isolated and pressure tested. Reviewers blindly scored each surgical team's performance based on actual inspection of the surgical site and on viewing videotapes of the procedure. The participants' attitudes toward the use of live animals in teaching and research were documented before and after training. No statistically significant differences could be detected between the two groups. The results suggest that some substitution of cadavers for live dogs in surgical training might be feasible.     

Features that contribute to the usefulness of low-fidelity models for surgical skills training

For practical, ethical and economic reasons, veterinary surgical education is becoming increasingly dependent on models for training. The limited availability and high cost of commercially produced surgical models has increased the need for useful, low-cost alternatives. For this reason, a number of models were developed to be used in a basic surgical skills course for veterinary students. The models were low fidelity, having limited resemblance to real animals. The aim of the present study was to describe the students' learning experience with the models and to report their perception of the usefulness of the models in applying the trained skills to live animal surgery. One hundred and forty-six veterinary fourth-year students evaluated the models on a four-point Likert scale. Of these, 26 additionally participated in individual semistructured interviews. The survey results showed that 75 per cent of the students rated the models 'useful'/'very useful'. Interviews revealed that tactile, dimensional, visual, situational and emotional features are important to students' perception of a successful translation of skills from models to live animal. In conclusion, low-fidelity models are useful educational tools in preparation for live animal surgery. However, there are specific features to take into account when developing models in order for students to perceive them as useful.     

Evaluation of a Hemostasis Model for Teaching Basic Surgical Skills

The need for alternative methods of teaching veterinary medicine and surgery has increased in recent years because of increasing costs and changing public opinion. For these reasons a hemostasis model was developed that mimics the arteries and veins of the peripheral vascular system, and can be used to teach the basic skills involved in blood vessel ligation and division. This study evaluated the effectiveness of the fluid hemostasis model compared with using live animals for teaching these skills. Forty sophomore veterinary students participated in the study. Two groups of 20 students each received identical instruction in the basic techniques required for vessel ligation and division. The students then completed various exercises using inanimate models to objectively evaluate their psychomotor skills. Both groups then practiced the techniques for equal time periods; one group used the hemostasis model and the other performed a splenectomy on live dogs. After the practice session, the students were videotaped (for later evaluation), as they performed vessel ligations and divisions. The students then repeated the exercises using the inanimate models for evaluation of skills improvement. Questionnaire responses before and after the project were obtained to determine the students' views on the need for inanimate models for teaching purposes. Results of this study indicate that the hemostasis model was as effective as live animals for teaching the basic skills involved in blood vessel ligation. The students' opinions regarding the use of properly designed inanimate models for teaching these skills were dramatically changed.     

Preservation of cadavers for surgical technique training

OBJECTIVE: To evaluate a technique for preservation of organoleptic tissue characteristics (color, odor, texture, and flexibility) in cadavers used for surgical instruction. STUDY DESIGN: Experimental study. ANIMALS: Forty-three canine cadavers. METHODS: Cadavers were preserved with a modified Larssen solution of the Hospital Cochim, Paris and cryopreservation. Tissue handling qualities were evaluated in surgical laboratory sessions. RESULTS: All cadavers kept texture and tissues consistency, especially skin and muscle, similar to those of live animals. Some skin desquamation and pallor of the mucous membranes occurred with repetitive freeze-thaw cycles. CONCLUSIONS: This preservation technique provides acceptable cadaver quality and tissue handling for use in surgical instruction. CLINICAL RELEVANCE: Preparation of patient cadavers by intravascular injection of modified Larssen solution yielded suitable instructional models for surgical training.     

Attitudes of veterinary medical students and medical students toward collaborative learning: an experiment

This study measured the attitudes of 55 medical students and 30 veterinary medical students as they participated in an experiment of collaborative teaching and learning about basic surgical skills. Two parallel forms of an attitude questionnaire were developed, with three subscales: confidence in one's own surgical skill; collaboration with the other type of student; and inter-professional collaboration in general. These attitude scales were administered before and after an experiment involving the veterinary medical students teaching the medical students incision and exploratory laparoscopy in a laboratory setting using live rabbits. After the experiment, measures of the medical students' attitudes had increased significantly on all three subscales. Measures of the veterinary students' attitudes increased significantly on two subscales but declined on the subscale of inter-professional collaboration.     

Teaching veterinary students using shelter animals

Veterinary teaching hospitals (VTHs) are experiencing case-load trends that have negatively affected efforts to prepare students for entry-level veterinary practice, particularly in the area of technical skills training. This article examines the clinical training available to veterinary students through a variety of collaborative shelter models. Benefits and potential problems related to initiating a collaborative shelter clinical training program are reviewed. Collaborative efforts between animal shelters and veterinary schools can provide crucial opportunities for outreach teaching initiatives, particularly for teaching medical and surgical skills.     

Surgical education: attitudes toward animal use in teaching surgery at Louisiana State University

Concerns over the use of animals in teaching have lead to a reduction in the number of live animal laboratories. A survey of 275 students and faculty was conducted to characterize their attitude toward the use of animals in teaching surgery. Respondents favored live animal use. They believed that model laboratories were helpful in learning aseptic technique and suturing skills but less helpful in learning tissue handling, dissection, hemostasis, or anesthesia.     

Development of a teaching laboratory aid for instruction of fine needle aspiration biopsy cytology technique

Specialized training is required to obtain adequate cytology smears by needle aspiration biopsy. An educational method that would provide opportunity for numerous trainees to acquire needle aspiration biopsy and cytodiagnostic skills, and which would not result in the interruption of teaching hospital patient care nor result in the use or sacrifice of animals from laboratory animal resources was sought. An aspiration biopsy cytology teaching aid was developed by placing portions of fresh organ tissue from routine submissions to the necropsy laboratory into a specimen container partially filled with chilled normal saline solution. Specimens were stored immersed in saline at 4 degrees C for up to 48 hours. Prior to the cytopathology teaching laboratory period, the specimen container was removed from storage and covered with a latex diaphragm. Instructors responsible for teaching cytodiagnostic techniques used this ex vivo aspiration biopsy cytology device for instruction of fine needle aspiration biopsy, specimen processing, and microscopy. In the teaching laboratory, puncture of the diaphragm and aspiration of a tissue sample with hypodermic needle and syringe was instructed to, and practiced by, numerous trainees simultaneously using clinical operative technique without the need for live animals. Trainees prepared and stained cytology smears as well as evaluated and interpreted specimens in a single, realistic exercise. Such training experience may improve ability of trainees to procure diagnostic-quality biopsy specimens for cytodiagnosis of lesions from clinic patients.     

If you build it,they will learn: A review of models in veterinary surgical education

Surgical skills are learned through deliberate practice, and veterinary educators are increasingly turning to models for teaching and assessing surgical skills. This review article sought to compile and review the literature specific to veterinary surgical skills models, and to discuss the themes of fidelity, educational outcomes, and validity evidence. Several literature searches using broad terms such as “veterinary surgery model,” “veterinary surgical model,” and “veterinary surgical simulator” were performed using PubMed, CAB abstracts, and Google scholar. All articles describing a model created and utilized for veterinary surgical training were included. Other review articles were used as a source for additional models. Commercially available models were found using review articles, internet browser searches, and communication with veterinary clinical skills educators. There has been an explosion of growth in the variety of small animal surgical task trainers published in the last several decades. These models teach orthopedic surgery, ligation and suturing, open celiotomy and abdominal surgery, sterilization surgeries, and minimally invasive surgeries. Some models were published with accompanying rubrics for learner assessment; these rubrics have been noted where present. Research in veterinary surgical models is expanding and becoming an area of focus for academic institutions. However, there is room for growth in the collection of validity evidence and in development of models for teaching large animal surgery, training surgical residents, and providing continuing education to practitioners. This review can assist with evaluation of current surgical models and trends, and provide a platform for additional studies and development of best practices.     

Effect of host age in the distribution of adult Trichinella zimbabwensis in the small intestines of golden hamsters (Mesocricetus auratus) and Balb C mice

Golden hamsters (Mesocricetus auratus) and Balb C mice were experimentally infected with Trichinella zimbabwensis to determine the effect of host age in the distribution of adult stages in the small intestines. The hamsters and mice were divided into two groups of young and old animals. Hamsters aged 90 days were designated as young and those aged 360 days were designated as old while mice of 30 days of age were designated as young and those aged 90 days as old. To recover the adult parasites of T. zimbabwensis, the small intestines of each animal were separated and divided into four equal parts and each part was slit open longitudinally. The contents were incubated in 0.85% saline for 4 h at 37 degrees C before the adult worms were recovered from the saline. They were fixed in 70% alcohol and counted under a dissecting microscope. In both young and old hamsters and mice, T. zimbabwensis adult worm counts were significantly higher (P < 0.05) in the second segment of the intestines thus invariably reflecting a significantly high count (P < 0.05) in the first (anterior) half of the small intestines. From this study it was demonstrated that host-age had no effect on the distribution of T. zimbabwensis adult worms in the different segments of the small intestines of golden hamsters and Balb C mice.     

澳大利亚高校教学方法对吉林农业科技学院学生动物实验技能提高的启示

在生命科学研究领域,实验动物和动物实验起着非常重要的作用,为了提高本科生动物实验技能的训练,以适应就业岗位的需要,结合澳大利亚高校教学方法,对吉林农业科技学院动物科技学院相关专业实验动物技术课程进行理论和实验教学内容及方法的调整与改进,在教学理念方面强调“以学生本”,理论教学采用小组合作式和以问题为导向的教学模式;实验教学以项目法结合教师科研以提高学生动物实验技能为目的,多种教学方法相互融合以提高教学效果,旨在提高该校本科生动物实验技能,提高科技创新能力及就业竞争力。     

Efficacy of ivermectin against inhibited larvae of Ostertagia ostertagi

The efficacy of ivermectin against inhibited early 4th-stage larvae of ostertagia ostertagi and other nematodes of the abomasum and intestinal tract was determined in naturally infected yearling beef cattle. The time when large numbers of inhibited larvae were acquired was determined by monthly slaughter of monitor cattle, beginning in January. In April, 12 animals were removed from pasture and maintained free of further helminth exposure until slaughter (21 days). At 9 days after the cattle were removed from pasture, ivermectin was administered to the principals by subcutaneous injection (200 micrograms/kg); the other 6 animals were given subcutaneous injections of the ivermectin vehicle. both groups were klled and necropsied at 12 days after treatment. Mean numbers of O ostertagi in the 6 controls were: adults, 41,906; developing 4th stage, 73,813; and early 4th stage, 334,965. The mean proportion of early 4th-stage larvae was 73.7%. In the 6 principals (treated with ivermectin), the following reductions were observed: O ostertagi adults, 100%; developing 4th stage, 99.8%; and early 4th stage, 99,9%. Small numbers of dead and degenerated O ostertagi of all developmental stages were recovered from abomasal washings before fixation; few viable worms were recovered.     

Effect of feeding tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on nutrient utilization,urinary purine derivatives and growth performance of goats fed on Quercus semicarpifolia leaves

To study the effect of supplementation of tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on growth performance, nutrient utilization and urinary purine derivatives of goats fed on oak (Quercus semicarpifolia) leaves. For growth study, eighteen billy goats (4 month old, average body weight 9.50 ± 1.50 kg) were distributed into three groups of six animals each. The animals of group 1 served as control while animals of groups 2 (T1) and 3 (T2) were given (@ 5 ml/kg live weight) autoclaved and live culture of isolate TDGB 406 (10⁶ cells/ml) respectively. The animals were fed measured quantity of dry oak leaves as the main roughage source and ad libitum maize hay along with fixed quantity of concentrate mixture. The feeding of live culture of isolate TDGB 406 (probiotic) did not affect dry matter intake and digestibility of nutrients except that of dry matter and crude protein, which was higher in T2 group as compared to control. All the animals were in positive nitrogen balance. There was no significant effect of feeding isolate TDGB 406 on urinary purine derivatives (microbial protein production) in goats. The body weight gain and average live weight gain was significantly higher (p = 0.071) in T2 group as compared to control. Feed conversion efficiency was also better in the goats fed on live culture of TDGB 406 (T2). The feeding of tannin degrading bacterial isolate TDGB 406 as probiotic resulted in improved growth performance and feed conversion ratio in goats fed on oak leaves as one of the main roughage source.     

Exploratory Celiotomy in 200 Nontraumatized Dogs and Cats

Two hundred dogs and cats undergoing exploratory celiotomy for reasons other than trauma were grouped by disease classification and by body system affected. There were 61 animals in which infection or inflammation predominated, 63 animals with neoplasia, and 76 animals with noninflammatory and non-neoplastic conditions. Body systems affected were digestive, lymphatic, urinary, reproductive, other, and undetermined. Seventy-three percent of the animals survived the hospitalization period; survival rates for animals with infection or inflammation, neoplasia, and other disorders were 69%, 60%, and 86%, respectively. Within the same groups, the exploratory celiotomy provided strictly diagnostic information in 72%, 79%, and 24% of the animals, and surgical treatment was provided to 28%, 21%, and 58% of the animals, respectively. Intraoperative cytologic and histologic diagnoses were consistent in 78% of the animals; the consistency rates for animals with infection or inflammation, neoplasia, and other disorders were 81%, 88%, and 59%, respectively. Complications after surgery were observed in 30% of the animals, with 60% of the complications disease related. Complications were observed in six animals with reproductive disorders (67%), six animals with urinary disease (46%), 35 animals with digestive disease (29%), and three animals with lymphatic disease (13%).     

Nephrosplenic Space Ablation in Horses After Homologous Pericardium Implant Using a Laparoscopic Stapler

This study aimed to describe and evaluate a laparoscopic technique to promote nephrosplenic space ablation in horses using a homologous pericardium implant, preserved in 98% glycerin and fixed using laparoscopic polydioxanone staples. In this experimental study, six Arabian horses without previous related abdominal diseases were used. The surgical procedures were performed in the standing position under sedation with alpha-2 agonists and opioids, associated with local infiltration of the local anesthetic in the portal sites. The horses were restrained in a stock, and the left flanks were clipped and aseptically prepared. Three portals were created on the left flank, and the homologous pericardium implant, measuring 10 × 5 cm, was introduced into the abdominal cavity covering the nephrosplenic space, positioned between the dorsal border of the spleen and perirenal fascia, fixed with polydioxanone staples using a laparoscopic stapler. Physical examination and blood and peritoneal fluid sample collection were performed on days 0, 1, 3, 7, 14, 30, and 60 of the postoperative period, and an exploratory laparoscopy was performed on day 60 to assess the effectiveness of the technique and eventual complications. There were no difficulties or significant complications during the surgical procedure, and the total average time to perform was 49.83 minutes (±10.19). In the postoperative period, there was a significant increase (P < .05) in the plasma fibrinogen concentration on days 7 and 14 compared with the preoperative moment. The total nucleated cell count in the peritoneal fluid increased (P < .05) on days 1, 3, 7, 14, and 30. After 60 days of the surgical procedure, the physical examination and laboratory data were within the normal range. Exploratory laparoscopy performed on day 60 revealed complete occlusion of the nephrosplenic space, and it was not possible to differentiate the pericardium implant from the scar tissue, not even in the histological evaluation performed on the collected samples. In two horses, omentum adhesion was observed in the region where the implant was fixed, and in two others, a synechia was observed between the implant area and mesocolon without association with clinical complications. The animals were followed up for 36 months at surgery, and no colic signs were observed along this period. It was concluded that the technique of ablation of the nephrosplenic space, using homologous pericardium preserved in 98% glycerin, fixed by polydioxanone staples by laparoscopy, was simple to perform, effective, and free of clinical complications during the period of evaluation, and its use may be indicated as a surgical option in clinical cases of horses with recurrent nephrosplenic entrapment.     

Lumbo-sacral epidural anaesthesia as a complement to dissociative anaesthesia during scrotal herniorrhaphy of livestock pigs in the field

Background

In Sweden, scrotal or inguinal herniorrhaphy of livestock pigs in the field has traditionally been an important part of the surgical skills training of veterinary students. Few substances meet the legal requirements for field anaesthesia of production animals in the European Union but a protocol based on azaperone-detomidine-butorphanol-ketamine does. Unfortunately the anaesthesia is characterised by unpredictable duration and depth and of abrupt awakenings which is not acceptable from an animal welfare perspective and impedes surgical training. Lumbo-sacral epidural analgesia is proven to provide sufficient analgesia to allow abdominal surgery, but there are few reports on the field use of this loco-regional technique. The study aim was to evaluate whether lumbo-sacral anaesthesia can be safely and successfully used in the field by a veterinary student and whether the combination of dissociative and lumbo-sacral epidural anaesthesia improves analgesia and anaesthesia to guarantee animal welfare during herniorrhaphy in livestock pigs, enabling surgical skills training.

Results

Pigs in the control-group (placebo) responded significantly stronger to surgery, with five out of 11 requiring additional doses of detomidine and ketamine. There were no significant differences between groups in respiratory rate, heart rate, blood pressure, SpO₂ or blood gases. SpO₂ levels <94 % were recorded in several pigs in both groups. No post-injection complications were reported at follow-up.

Conclusions

The results from this study showed that lumbo-sacral epidural anaesthesia with lidocaine could successfully be administered during dissociative anaesthesia of livestock pigs by a veterinary student and without reported post-injection complications. It improved analgesia and anaesthesia during herniorrhaphy of sufficient duration to enable surgical skills training. The risks and consequences of hypoxaemia and hypoventilation should be considered.