Providing veterinary graduates with surgical skills expected of entry-level veterinarians is essential in meeting increasing public demand for quality care in small animal and equine practices. Substantial effort has focused on characterizing expectations for entry-level veterinarians and defining core surgical skills. In a 2004 study,1 67% of responding general practitioners expected incoming veterinarians to be familiar with and proficient in surgical sterilization, basic wound management, basic dental procedures, and other routine procedures. More recently, 60% of general practitioners and Diplomates of the American College of Veterinary Surgeons expected newly hired graduates to demonstrate 21 of 26 surgical skills listed in the survey with minimal supervision.2,3 As a consequence, curricula in most veterinary colleges have evolved to emphasize basic surgical skills and routine elective procedures. Among those, ovariohysterectomy is generally perceived as the most complicated sterilization technique taught to students. Complications have been reported in up to 13.7% of dogs undergoing routine ovariohysterectomy,4 and hemorrhage has been reported as the most common complication after elective ovariohysterectomy in teaching institutions where surgery is performed by veterinary students.5 In a study6 of postoperative morbidity associated with ovariohysterectomies performed by third-year veterinary students, body wall dehiscence was identified as the most common major complication (in approx 3% of cases).
Entry-level veterinarians are expected to master routine elective procedures; however, surgical techniques are constantly evolving to improve efficiency and decrease morbidity. In human and veterinary medicine, laparoscopy has been proposed to reduce blood loss, postoperative pain, stress, hospitalization, surgical recovery time, and incision-related complications as well as to improve cosmetic outcomes.7–9 Laparoscopy has consequently become the standard of care for many surgical procedures in human medicine. In veterinary medicine, this approach is gaining worldwide popularity for surgical procedures in horses and small animals.10–12 Although sterilization procedures are usually performed by routine open surgical techniques in general veterinary practices, laparoscopic procedures are gaining more popularity. The public increase in demand for laparoscopic surgery raises the question as to whether surgical curricula should evolve toward training veterinary students in this diagnostic and surgical method.
In human medicine, a fundamental laparoscopic surgery training program was established in the late 1990s to provide training and assessment of basic laparoscopic skills.13,14 This program uses the validated MISTELS.13–15 The MISTELS requires trainees to perform 5 tasks on a physical trainer box, each scored on time and number of errors.13–18 Although this program is well established for its ability to improve basic laparoscopic skills15–20 and its strong correspondence with surgical performance in vivo,21 it is not designed to evaluate complex skills, such as tissue and instrument handling.11 Those skills are best evaluated by use of the OSATS, providing a composite score on the basis of rubrics for each surgical skill observed during predetermined laparoscopic surgery tasks.11,22–24 These concepts were consequently adjusted to serve as laparoscopic skills assessment tools for veterinarians.10,11,25 The MISTELS and OSATS have been used to document the ability of surgery fellows, residents, and veterinarians to train for laparoscopic surgery and compare the efficacy of training models.25–27 A recent study10 reported on the ability of inexperienced veterinary medicine students to acquire basic laparoscopic skills and achieve overall scores similarly to those of experienced veterinarians enrolled in the same training program. Although this study10 also demonstrated an aptitude for veterinary medicine students to perform tasks in a training model and acquire basic laparoscopic skills, their ability to perform a laparoscopic ovariectomy in live dogs has not been evaluated.
The purposes of the study reported here are to determine the ability of veterinary students to acquire basic laparoscopic skills and perform laparoscopic ovariectomy in live dogs, compared with the ability to acquire basic surgery skills and perform open ovariectomy in live dogs. We hypothesized that students in both groups would have similar confidence and basic surgical skills prior to training and that performance during a laparoscopic ovariectomy by students who received specific training in laparoscopic ovariectomy would be similar to performance during an open ovariectomy by students who received training in open ovariectomy.
Materials and Methods
Human subjects—The Western University of Health Sciences Institutional Review Board for Protection of Human Subjects approved student participation. All veterinary students completing their second year at this institution were invited to enroll in the study. At this stage of the curriculum, students receive training in basic surgical skills and assist on neutering surgeries but have not acted as a primary surgeon. At the time of the study, the curriculum did not provide any exposure or training in laparoscopic surgery. The students completed a questionnaire evaluating their prior surgical experience, specifically with regard to their experience as assistant and primary surgeon in conventional and laparoscopic ovariectomies or ovariohysterectomies. Students were included in the study if they did not have previous experience in conventional or laparoscopic ovariectomy or ovariohysterectomy in dogs or cats as a primary surgeon and if their experience as an assistant, in either conventional or laparoscopic surgical sterilization techniques, did not exceed 10 procedures. Each student was provided a study identification number and randomly assigned with online randomization softwarea to receive specific training in either open or laparoscopic ovariectomy.
Animals—The Western University of Health Sciences Institutional Animal Care and Use Committee approved this study. Shelter-owned dogs scheduled to undergo ovariectomy at the university prior to adoption by the public were enrolled. Dogs were eligible if they were healthy sexually intact females, > 3 months of age, and > 8 kg (> 17.6 lb). Prior to surgery, all dogs underwent physical examination, serum biochemical analysis, and hematologic testing.
A standardized anesthesia and analgesia protocol was provided under the direct supervision of a board-certified anesthesiologist (LYL). For anesthetic preparation, food was withheld 12 hours prior to surgery but fresh water was available ad libitum. All dogs were premedicated with a combination of acepromazine and butorphanol administered SC. Approximately 20 minutes later, anesthesia was induced by IV administration of propofol titrated to effect. The urinary bladder of each dog was expressed, and general anesthesia was maintained with sevoflurane and oxygen.
The following variables were measured continuously: ECG, rectal temperature, end-tidal partial pressure of CO2, systemic arterial blood pressure, and hemoglobin oxygen saturation during anesthesia. Lactated Ringer solution was continuously administered IV during the entire operational procedure. Dogs were placed on mechanical ventilation throughout the laparoscopic surgery. All dogs received postoperative pain control medication that included ketoprofen and butorphanol at the completion of surgery. Anesthetic recovery was monitored and continually assessed on the basis of respiratory rate, heart rate, and rectal temperature until the dog regained a strong swallowing reflex and the endotracheal tube was extubated.
Student training—All participating students were completing their second year of veterinary training. During the first 2 years of the curriculum, students received 16 hours of basic surgery skills (eg, instrument introduction and handling, suture introduction, and suture patterns) training and 16 hours of surgical observation of castrations and ovariohysterectomies or ovariectomies. During the first 2-year period, the students had 8 tests (twice a semester) to assess their basic surgery skills with an objective structured clinical examination.
For this study, each student received 14 hours of training divided into 7 laboratories of 2 hours each over the course of 8 weeks. Both group training programs followed similar phases, starting with relevant basic skills, followed by video and practice on models designed to simulate open or laparoscopic ovariectomy, depending on group assignment. All students owned basic suturing models and had free access to them at all times. Laboratories were held separately in a large clinical skills facility on campus, and participants were required to attend them. The pretraining assessment was applied before the first training session, and the post-training test was applied after the last training session. The ovariectomy surgery procedures in live dogs began 3 weeks after the last training laboratory (because of examinations) and took 10 days until all students from both groups performed the ovariectomy required to complete the study.
The open ovariectomy training began with an initial 2-hour laboratory that included attendance of a lecture and discussion about the open ovariectomy technique. The discussion included a question-and-answer session after students watched a video of an open ovariectomy, followed by a demonstration and practice on the use of the surgery instruments for open ovariectomy. During the next 6 laboratories (2 hours each), the students had free access to models for suture pattern and hand and instrument ties practice as well as access to surgical instruments used during the ovariectomy procedure. During the training period, they also had free access to handouts and a video of an open ovariectomy (created for the third-year surgery course). Finally, during all of the last 6 sessions, students also practiced midline celiotomy and ovariectomy with custom-designed models currently used in the surgery curriculum. The custom-designed models for the midline celiotomy consisted of 2 pieces of fabric attached to a flat piece of a carton, with a narrow line between the pieces to mimic the body wall incision. The custom-designed ovariectomy model consisted of plastic wrap shaped to form a uterine body and 2 uterine horns with ovary marks on each horn. The model was taped to the table. During each laboratory, the students were free to practice each task at their own pace. Because of the 3-week interval between the last training laboratory and the surgery on live dogs, a review session was organized 1 day prior to the in vivo open ovariectomy procedure. The review session allowed students to practice the open ovariectomy procedure on the same models as those in the training laboratories and included another question-and-answer session.
The laparoscopic ovariectomy training began with the first 2-hour laboratory that included attendance of a lecture and discussion about the laparoscopic ovariectomy technique. The discussion included a question-and-answer session after observation of a video of a laparoscopic ovariectomy, followed by a demonstration and practice on the use of the laparoscopic surgery instruments. The videos provided instruction on laparoscopic equipment, basic laparoscopic techniques,b and laparoscopic ovariectomy in dogs.c Students were trained in laparoscopic basic skills with a standard laparoscopic tower and instruments,d a laparoscopic box trainere for basic skills (Figure 1), and a laparoscopic simulatorf that simulates an inflated canine abdomen and artificial organs for the training of ovariectomies (Figure 2). During the training period, they received free access to handouts and videos on laparoscopic instruments and technique. During the remainder of the 6 sessions, students then practiced 2 laparoscopic training exercises: pegboard transfer (Figure 3) and circle pattern-cutting (Figure 4), as described in the MISTELS program. The pegboard transfer task required students to transfer 6 rings from one pegboardg to another, then reverse the exercise. The pattern-cutting exercise required students to cut a 4-cm-diameter circular pattern of glove paper wrapping, with a laparoscopic grasperh in one hand and laparoscopic scissorsi in the other. In addition, students practiced removing a cautery-cutting pattern with a bipolar vessel sealing devicej on a canine uterine specimen. Finally, students practiced each step of a laparoscopic ovariectomy with the laparoscopic simulator.f At each laboratory, students were at liberty to decide how long to practice each task within the 2 hours allocated for each laboratory. Students were able to practice suturing on models during their free time. Because of the 3-week interval between the last training laboratory and the surgery on live dogs, a review session was organized 1 day prior to the laparoscopic ovariectomy procedure. The review session allowed students to practice the laparoscopic ovariectomy procedure on the same models as the training laboratories and included another question-and-answer session.
Photograph of a laparoscopic box trainer used by students to practice basic laparoscopic skills.
Citation: Journal of the American Veterinary Medical Association 247, 11; 10.2460/javma.247.11.1279
Photograph of a laparoscopic simulator. This model reproduces an inflated abdominal cavity containing artificial organs, thereby allowing students to practice and simulate each step of a laparoscopic ovariectomy for a dog.
Citation: Journal of the American Veterinary Medical Association 247, 11; 10.2460/javma.247.11.1279
Photograph of a pegboard transfer task for developing basic laparoscopic skills. Students must transfer 6 rings from one pegboard to another, and reverse the exercise.
Citation: Journal of the American Veterinary Medical Association 247, 11; 10.2460/javma.247.11.1279
Photograph of a circle pattern cutting task for developing basic laparoscopic skills. Students were required to cut a 4-cm-diameter circular pattern, with a laparoscopic grasper in one hand and laparoscopic scissors in the other hand, avoiding both external and internal circles.
Citation: Journal of the American Veterinary Medical Association 247, 11; 10.2460/javma.247.11.1279
Student questionnaire and anatomy test before and after training—Students from both groups were asked to rate their confidence in performing both open and laparoscopic ovariectomies in dogs as a primary surgeon on a 4-point scale (1 = not prepared at all, 2 = not well prepared, 3 = well prepared, and 4 = very well prepared) before and after training in their respective groups. To assess their overall confidence in basic surgery skills, a score was developed to combine student responses regarding their confidence to identify and select (1 to 4 points) and handle (1 to 4 points) surgical instruments used in open ovariectomy. To assess their overall confidence in basic laparoscopic surgery skills, a score was developed to combine student responses regarding their confidence to identify and select (1 to 4 points) and handle (1 to 4 points) instruments used in laparoscopic surgery. In addition, their knowledge of anatomy relevant to an ovariectomy was evaluated with a written test before and after training. In this test, students were scored on a scale of 19 points on the basis of their ability to identify the linea alba, ovary, suspensory ligament, proper ligament, mesovarium, mesometrium, and associated vasculature.
Assessment of psychomotor and basic surgical skills before and after training—Psychomotor and basic surgical skills were assessed in both groups, before and after training, with the same set of tests previously validated by Olsen et al28 and Griffon et al.29 Briefly, the time needed for students to pass a needle through consecutive eyelets fixed to a suture board was recorded. Students were asked to place a circumferential ligature around a foam cylinder. Their performance was scored with a 4-point rubric. On completion, the suture was cut and its length around the cylinder measured as an indicator of tightness of the suture. Students also placed a circumferential ligature around standardized medical grade latex tubing.k To assess the effectiveness of the circumferential ligature for hemostasis, the same investigator throughout the study injected water through a 60-mL syringe connected to the ligated tube, looking for leaking by measuring the volume of water injected during 5 seconds. Volumes < 1 mL were assigned a score of 1 (good hemostasis [ie, tight enough]), volumes between 1 and 6 mL were assigned a score of 2 (intermediate hemostasis), and volumes exceeding 6 mL were assigned a score of 3 (unsuccessful hemostasis). Ability of students to close a simulated abdominal wall with a simple continuous suture pattern was scored with a 4-point rubric.
Assessment of basic laparoscopic skills before and after training—Basic laparoscopic skills were assessed in all students before and after training. Among the exercises included in the MISTELS, the pegboard transfer and pattern cutting (Figures 3 and 4) were specifically selected as outcome measures because they are most relevant to the skills required for ovariectomy and have been validated and used in previous studies10 of veterinary medical students in their preclinical education. Both tasks were evaluated on the basis of time for completion, with a cutoff time of 300 seconds.13,14,25 In both tasks, student performance (time for completion) was evaluated by the same instructor. Correction of mistakes made by students during the task scorings (peg drops and out-of-line cutting) was included as a component of the time to completion, without point deduction, to maintain the scoring to be as objective as possible.
Evaluation of students performing an ovariectomy on a live dog—All students received general surgical assistance by the same faculty surgeon (OL). The surgeon's assistance consisted of routine tasks such as tissue retraction or holding the camera in place, as directed by the student. The supervising surgeon was advised not to intervene unless indicated to prevent technical errors. Surgical time was limited to 120 minutes for all procedures, with time limits set for each surgical step (ie, blade on scalpel, 2 minutes; skin incision and celiotomy, 20 minutes; localization of ovaries, 8 minutes each; ligation and removal of ovaries, 25 minutes each; and 2-layer closure, 32 minutes). Surgery start time in both techniques was from when the blade was placed on scalpel, and stop time was when the last skin suture was placed. If the student reached the 120-minute maximum time, the supervising surgeon would take over and points would be deducted from the score. A professional videographer recorded only the surgical field of each procedure, which served for evaluation of the surgery performance and masked student identities from the evaluators. For the laparoscopic procedure, internal recording was also taken. Two investigators (OL and DJG) graded all procedures on the basis of observations from video and audio recordings for the open ovariectomy. The laparoscopic ovariectomies were scored on the basis of observations from external video and audio recordings as well as laparoscopic videos. Scores from both investigators were averaged to obtain an ovariectomy score for each procedure. In both groups, major complications were defined as those requiring treatment.
Open ovariectomy—Each student performed a conventional ovariectomy as described by Culp et al.30 Briefly, a midline celiotomy allowed exposure of the ovaries. Two ligatures were placed on the ovarian pedicle and the cranial end of the uterine horn prior to transection. The procedure was repeated on the contralateral side prior to routine, 2-layer closure of the surgical wound with a simple continuous suture pattern for the body wall and a continuous vertical intradermal suture pattern for skin apposition.31
The rubric used to evaluate open ovariectomy in our study was derived from a scoring system described by Griffon et al29 to evaluate student performance during open ovariohysterectomy.
Open ovariectomies were evaluated by 2 investigators on the basis of the same 55-point system described by Griffon et al29 The scoring system allocates 10 points to establish a view of the surgical field (midline celiotomy), 19 points for the identification and proper excision and removal of each ovary, and 7 points for closure of the abdominal wound. Instrument selection and handling, along with basic surgical skills, were evaluated within each step listed. A rubric with specific items to deduct points from was developed for the evaluators. On the basis of the rubric, evaluators were able to deduct points for each intervention of the supervising surgeon.l
Laparoscopic ovariectomy—Each student performed a laparoscopic ovariectomy with a 2-portal technique described by Dupre et al.32 Dogs were placed in dorsal recumbency, and abdominal insufflation (10 to 15 mm Hg) was achieved with a Verres needle.m,n After proper insufflation, a 5-mm cannulao was placed just caudal to the umbilicus and a 10-mm cannulap was placed under laparoscopic guidance midway between the xiphoid and the umbilicus. The abdominal cavity was examined, and the patient partially turned laterally to better expose the ovary and uterine horn. The proper ligament was grasped with Babcock grasper forcepsq and the ovary secured to the lateral abdominal wall with a J hook needle.r The suspensory ligament, mesovarium, and uterine horn were sealed and transected with a vessel-sealing device.j The ovary was removed through the cranial cannula. The procedure was repeated for the second ovary. The abdomen was evaluated for hemorrhage prior to decompression and removal of the cannulas. Portals were closed in 2 layers, with the body wall closed with 1 or 2 simple interrupted sutures (depending on the size of the portal) and the skin closed with 1 or 2 buried intradermal sutures. The rubric developed for laparoscopic ovariectomy evaluation incorporated part of the rubric for the open ovariectomy (surgery skills assessment described by Griffon et al29) and the previously validated parameters from the OSATS for laparoscopic surgery skills developed from the Global Operative Assessment of Laparoscopic Skill, including 4 evaluation categories: depth perception, bimanual dexterity, efficiency, and proper use of instruments.11,33 A 55-point scoring system was designed to ensure a similar distribution of points for each step of the ovariectomy in each group: the score allocated 10 points to establish a view of the surgical field (celiotomy or creation of portals), 19 points for the identification and proper excision and removal of each ovary, and 7 points for closure of the abdominal wounds. Instrument selection and handling, along with basic surgical and laparoscopic skills, were evaluated within each step listed. Similar to the open ovariectomy procedure, a rubric was developed to deduct points for each intervention of the supervising surgeon. On the basis of the rubric, evaluators were able to deduct points for each intervention of the supervising surgeon (deduction of 1 or 2 points for advice and deduction of 3 points for active intervention), and excessive duration of surgery and complications (5 or 6 points deduction for trauma to soft tissue or organ and 5 or 6 points for thermal injury to tissue or organ and hemorrhage during or after ovarian cautery or cutting with the sealing device).
Data analysis—Scores are presented as medians and ranges. The exact Mann-Whitney test was used to compare confidence, anatomy knowledge, psychomotor skills, and basic laparoscopic skills data between open and laparoscopy groups. The same test was used to compare duration of surgery, number of complications, and technical score for the open ovariectomy or laparoscopic ovariectomy (average of scores from 2 investigators) at the end of the study. Exact Wilcoxon signed rank tests were used to compare scores before and after training related to anatomy knowledge, psychomotor skills, and confidence. Values of P < 0.05 were considered significant.
Results
Twenty-five second-year veterinary students who volunteered met the criteria for inclusion and completed the study, and 25 dogs successfully underwent ovariectomy surgery with no major complications. Thirteen students were randomly assigned to receive training in open ovariectomy, and 12 students were assigned to receive training in laparoscopic ovariectomy. Both groups had a similar gender distribution (1 male student in each group).
Student confidence before and after training—All students had similar surgical experience, having each observed a maximum of 5 conventional ovariectomies or ovariohysterectomies and served as assistants on up to 5 additional conventional ovariectomies or ovariohysterectomies. None of the students had prior exposure to laparoscopic surgery. Results of the questionnaire were summarized (Table 1). Both groups expressed similar levels of confidence in all aspects tested before training. Confidence was assessed from the questionnaire after training and before surgeries started. Student confidence regarding open ovariectomy did not improve with training in either open ovariectomy (P = 0.38) or laparoscopic ovariectomy (P = 0.25) and did not differ between groups after training (P = 1.0). The only significant differences detected between groups consisted of greater confidence after training with regard to laparoscopic ovariectomies in students who received training in laparoscopic ovariectomy, compared with students who received training in open ovariectomy (P < 0.001), and an improvement in confidence following training in laparoscopic ovariectomy (P = 0.001).
Median (range) scores of student confidence and surgical skills in ovariectomy, before and after training for conventional open ovariectomy (n = 13) versus training for laparoscopic surgery (12).
| Variable | Open | Laparoscopic | P value |
|---|---|---|---|
| Basic surgical skills (2–8 points) | |||
| Before training | 6 (4–7) | 6 (5–7) | 0.59 |
| After training | 6 (4–8) | 6 (5–8) | 0.92 |
| P value | 0.094 | 0.40 | |
| Basic laparoscopic skills (2–8 points) | |||
| Before training | 2 (2–4) | 2 (2–4) | 0.72 |
| After training | 3 (2–5) | 6 (5–8) | < 0.001 |
| P value | 0.007 | < 0.001 | |
| Performing an open ovariectomy (1–4 points) | |||
| Before training | 2 (2–3) | 3 (2–3) | 0.43 |
| After training | 3 (2–4) | 3 (2–4) | 1.00 |
| P value | 0.070 | 0.38 | |
| Performing a laparoscopic ovariectomy (1–4 points) | |||
| Before training | 1 (1–2) | 1 (1–2) | 1.00 |
| After training | 1 (1–2) | 3 (2–3) | < 0.001 |
| P value | 1.00 | 0.001 | |
Student knowledge and skills before and after training—Scores related to anatomy knowledge and psychomotor, basic surgical, and laparoscopic surgical skills in students before and after conventional surgery versus laparoscopic surgery were summarized (Table 2). None of these measures differed between students who received training in open ovariectomy versus laparoscopic ovariectomy before training. Scores related to knowledge of the anatomy and basic surgical skills remained unchanged in each group and did not differ between groups at the end of the study. The only unexplained exception consisted of the score assigned for ligation of the latex tube, which was significantly (P = 0.03) higher after training in laparoscopic ovariectomy, compared with students who received training in open ovariectomy, with no obvious explanation for this difference.
Median (range) scores of anatomy knowledge and psychomotor, basic surgical, and laparoscopic skills in students before and after conventional open (n = 13) versus laparoscopic (12) surgical training.
| Test | Open | Laparoscopic | P value |
|---|---|---|---|
| Knowledge of anatomy (0–19 points) | |||
| Before training | 15 (12–17) | 15 (11–18) | 0.58 |
| After training | 16 (12–17) | 15 (13–17) | 0.49 |
| P value | 0.48 | 0.68 | |
| Time to perform the electronic board test (s) | |||
| Before training | 244 (165–337) | 237 (166–361) | 0.91 |
| After training | 221 (162–274) | 236 (162–467) | 0.26 |
| P value | 0.35 | 0.30 | |
| No. of times the alarm (buzz) sounded per test | |||
| Before training | 13 (1–27) | 5 (2–19) | 0.51 |
| After training | 15 (4–25) | 4 (1–9) | < 0.001 |
| P value | 0.24 | 0.047 | |
| Score for ligation around latex tube (1–4) | |||
| Before training | 2 (1–4) | 3 (1–4) | 0.35 |
| After training | 2 (1–4) | 4 (2–4) | 0.03 |
| P value | 0.80 | 0.11 | |
| Length of suture material around foam cylinder (mm) | |||
| Before training | 63 (51–86) | 64 (52–72) | 0.80 |
| After training | 58 (47–74) | 56 (48–68) | 0.33 |
| P value | 0.28 | 0.054 | |
| Volume of water injected through a ligated tube (1–3) | |||
| Before training | 1 (1–3) | 1 (1–3) | 1.0 |
| After training | 2 (1–3) | 1 (1–3) | 0.14 |
| P value | 0.17 | 0.13 | |
| Score for suturing the abdominal wall (1–4) | |||
| Before training | 3 (1–4) | 3 (2–4) | 0.067 |
| After training | 3 (2–4) | 4 (3–4) | 0.19 |
| P value | 0.016 | < 0.001 | |
| MISTELS score | |||
| Peg transfer (0–300 s)* | |||
| Before training | 16 (0–124) | 20.5 (0–174) | 0.52 |
| After training | 68 (0–172) | 185.5 (138–236) | < 0.001 |
| P value | 0.067 | 0.001 | |
| Pattern cutting (0–300 s)* | |||
| Before training | 0 (0–92) | 0 (0–133) | 0.22 |
| After training | 10 (0–172) | 160 (0–236) | < 0.001 |
| P value | 0.031 | 0.002 | |
Values of 0 seconds indicate that surgical task was not completed within the 300 seconds allowed.
For students who received training in open ovariectomy, all assessments related to laparoscopic skills remained unchanged, except for the MISTELS score assigned to the pattern-cutting task, which improved significantly (P = 0.031) after training. As expected, all evaluations of the peg transfer and pattern-cutting tasks were significantly (P < 0.001) better in students who received training in laparoscopic ovariectomy, compared with students who received training in open ovariectomy in the end of the study (Table 2).
Student performance of an open versus laparoscopic ovariectomy—Thirteen open ovariectomies and 8 laparoscopic ovariectomies were scored. No postoperative complications were noted prior to discharge from the hospital or the day after surgery. Four laparoscopic ovariectomies could not be scored because of technical issues with the laparoscopic video capture system, preventing evaluation of intra-abdominal procedures, and hence were not considered for study inclusion. Overall, ovariectomy scores were not significantly (P = 0.74) different between students performing an open ovariectomy (34.5; range, 16.5 to 45) and those performing a laparoscopic ovariectomy (34.5; range, 25 to 44.5). However, surgery time was significantly (P = 0.001) shorter for open ovariectomy (80 minutes; range, 62 to 117 minutes) than for laparoscopic ovariectomy (129 minutes; range, 84 to 143 minutes). Complications of laparoscopic ovariectomy included 2 cases of spleen puncture by insertion of the Verres needle during insufflation, 1 case of burn injury to the body wall by the sealing device, and 1 case of mild pedicle hemorrhage due to excessive tearing by the sealing device. No other complications occurred in the study, and students maintained their roles as primary surgeons throughout all procedures. For students who received training in laparoscopic ovariectomy, the supervising surgeon had to intervene and complete the portals and skin closures in 6 of 8 laparoscopic ovariectomy procedures after the students reached the 120-minute time limit. The most common interventions from the supervising surgeon for students who received training in open ovariectomy occurred during ligation of the ovarian pedicle in open ovariectomies (mainly because the ligature was not tight enough or students requested assistance for better exposure of the ovarian pedicle) and during insertion of the J hook needle during the laparoscopic ovariectomy (mainly for hesitation to push the needle through the skin).
Discussion
The main findings of this study were that both training programs in open and laparoscopic ovariectomy resulted in similar, limited impacts on student basic surgical skills and knowledge of anatomy; the laparoscopic training was effective at improving student confidence and skills in basic laparoscopic skills; and students required additional time but achieved similar scores when performing laparoscopic ovariectomies, compared with open ovariectomies.
All students in both groups had similar previous experience and confidence at the beginning of the study, allowing us to compare the effects of each training program. Neither training program had a major impact on their overall basic surgical skills. Unexpectedly, student confidence to perform open ovariectomy did not change with training in either group and did not differ between groups after training. In the pretraining questionnaire, students reported good confidence and knowledge of relevant anatomy for basic surgery skills and for the open ovariectomy procedure. The high confidence before training could be explained by the curriculum designed to provide practical training in basic clinical skills as soon as students enter the program, which included weekly laboratory sessions, observation of ovariectomy procedure during their first 2 years, and direct examination of their skills every 8 weeks. Findings of the present study may reflect the preexisting aptitude of the students at the end of the second year of their veterinary education. Students likely had already acquired the basic surgical skills tested in this study and had reached a plateau that was unaffected by the relatively short training programs tested. The duration of the training period (14 hours) in both groups was selected on the basis of the already impacted schedule of the students, faculty, and staff and on previous studies10,25,34 probing the ability of residents or clinicians to acquire laparoscopic surgical skills. The content and design of open ovariectomy training emulated the current curriculum designed to prepare students to perform open ovariectomy as primary surgeons in the third year of veterinary education, with a supervisor acting as assistant surgeon. In contrast and as expected, student confidence in basic laparoscopic skills significantly improved after training in laparoscopic ovariectomy and was higher than in students who received training in open ovariectomy at the end of the study. We observed moderate but significant improvement for students who received training in open ovariectomy in 1 laparoscopic task: the cutting pattern. Although students who received training in open ovariectomy did not receive any laparoscopic training, this improvement may reflect exposure to the laparoscopic tasks during the pretraining laparoscopic test. One study35 showed that 1-time exposure could lead to retest improvement. Our findings likely reflect the value of the training and the lack of prior exposure to laparoscopic surgery. Students started with lower confidence in laparoscopic basic skills (median, 2) than basic surgery skills (median, 6), leaving more room for improvement as a result of the training. Similar changes were noted for parameters evaluating basic skills in laparoscopy, all improving with training in laparoscopic ovariectomy and reaching higher values at the end of the study than those for students who received training in open ovariectomy. The laparoscopic ovariectomy training program was derived from the MISTELS, an inanimate simulator that has become standard for training and assessment by the Society of American Gastrointestinal and Endoscopic Surgeons in their Fundamentals of Laparoscopic Surgery program. The MISTELS certification program for surgeons is one of the eligibility requirements for the American Board of Surgery examination.14 This model is designed to allow trainees to acquire basic laparoscopic skills applicable to a variety of procedures.14,18 Although performing laparoscopic procedures has become a requirement for certification in the American College of Veterinary Surgeons, there is no mandatory requirement for certification by the MISTELS or any other laparoscopic training and assessment program. Because of the lack of published information and agreement regarding what level of training is acceptable for performing a certain procedure in clinical cases, this study's training was complemented by an inanimate simulator with artificial abdominal organs, including those of the female reproductive system.f This model was selected to provide training specific to a laparoscopic ovariectomy. Finally, we incorporated practice with a bipolar vessel-sealing devicej to prepare students for hemostasis, transection, and removal of the ovarian pedicles. The bipolar device offered easier and more secure hemostasis.36
Outcome measures related to basic laparoscopic skills were aimed at testing unique skills required for laparoscopy, such as loss of depth of perception and triangulation. Indeed, laparoscopic procedures require surgeons to transfer an image displayed on a 2-D monitor into 3-D movement, instead of direct observation of the surgery site during an open surgery. In addition, laparoscopic instruments are highly specialized, operated with a fulcrum effect, and require triangulation.11,37 Our assessment was made on the basis of the MISTELS because it has been well established for its reliability, ability to improve surgical skills, and correlation with performance in vivo.13,15,18,19,21 To avoid interevaluator variation, all assessments of laparoscopic skills were performed by the same investigator (OL). Although this investigator could not be blinded to group status, MISTELS scores were determined on the basis of the time required to perform a task, mitigating observer bias. Our evaluation was limited to 2 of 5 tasks within the MISTELS: peg transfer and cutting pattern. The other 3 tasks (ligature loop placement and extracorporeal and intracorporeal suturing) were not included because of less relevance for the ovariectomy procedure and lack of training time (the learning curve for these 3 tasks is considerably steeper than for the 2 tasks used). Instead, these tasks were replaced by training with a vessel-sealing unit subsequently used in the in vivo laparoscopic ovariectomies. Partial inclusion of MISTELS tasks has been found to be sufficient to test the impact of laparoscopic training for novice surgeons.10,38 Similar to previous studies, our results demonstrate that this specifically designed training program improved basic laparoscopic skills among veterinary students. For training and performing various laparoscopic procedures that require laparoscopic suturing ability, the remainder of the 3 MISTELS tasks is important to apply and is beneficial for the confidence of the surgeon and the safety of the patient. The scoring of the 2 MISTELS tasks was determined on the basis of the total time for compilation of the task and included time needed to correct mistakes (peg drops for the peg transfer task and out-of-line cutting in the cutting pattern task). That completion time reflected directly on the ability of the student to complete the task. The deviation from the original penalty system of the MISTELS is because of the fact that the evaluator of those laparoscopic tasks was the same person who trained the students (OL); with the present scoring system, we succeeded in better keeping the evaluation objective. Completion time was significantly shorter in both laparoscopy tasks for students who received training in laparoscopic ovariectomy, compared with training in open ovariectomy.
The ovariectomy procedures on live dogs began 3 weeks after the training and assessment of the laparoscopic tasks. Open and laparoscopic ovariectomy surgeries started with 4 days of difference between the groups. The last set of students who received training in laparoscopic ovariectomy had a gap of 3 weeks and 4 days between training and surgery, and the first set of students who received training in open ovariectomy had a gap of 3 weeks and 5 days. Overall, both groups had at least 3 weeks of a gap, with probably no different impact on the surgery performance. Each surgical procedure was evaluated by 2 investigators (OL and DJG), both blinded to the identity of the student group assignment; one of them (DJG) was not involved at all in their training. After the 2 surgeons evaluated and scored each of the videos of the ovariectomies in live dogs, the scores of each group were averaged to calculate an ovariectomy score. The ovariectomy score of students who received training in laparoscopic ovariectomy was similar to the ovariectomy score of students who received training in open ovariectomy.
For both groups, major complications did not occur during or after surgery. Use of a sealing device was likely instrumental in lowering the technical difficulty to achieving proficiency. A few complications for the laparoscopic ovariectomy occurred during this study, including puncturing the spleen during placement of the Verres needle for insufflation (in this case, the supervising surgeon took over this step to avoid major complications). Another complication, common when the sealing device was used, was burn trauma to the body wall. In this case, the supervising surgeon had to caution the student. One more complication in use of the sealing device was hemorrhage resulting from excessive tissue tearing by the sealing device, which in one case led to mild hemorrhage from the pedicle; the student resolved the hemorrhage with no advice needed. An important finding of this study was that the median surgery time was significantly prolonged in students who received training in laparoscopic ovariectomy (129 minutes; 84 to 143 minutes), compared with students who received training in open ovariectomy (80 minutes; 62 to 117 minutes). This could be explained by the steeper learning curve needed to reach basic laparoscopic proficiency due to overcoming hand-eye coordination and depth perception learning obstacles.
An important limitation of this study was the limited number of investigators with expertise in minimally invasive surgery. As such, a single instructor (OL) served as evaluator. Assessment of basic surgery skills and basic laparoscopic skills was therefore not performed in a blinded fashion, although it relied on quantitative assessment. In addition, both investigators were unaware of student identities while scoring the surgeries.
The lack of improvement in the confidence of students for the open ovariectomy procedure after training in open ovariectomy was unexpected. On the basis of input from students after the study, it became apparent that they appreciated the minor increase in confidence in the open ovariectomy procedure but were unable to express this in the questionnaire because the answer categories were too broad. A questionnaire offering an option of some improvement in confidence may help to better identify minor improvement.
Results of the present study indicate that acquisition of laparoscopic skills in box trainers and simulators was effective at improving student confidence and ability to perform laparoscopic ovariectomy with a supervising surgeon. This study is the first to document the ability of students to perform laparoscopic ovariectomy at a level similar to that achieved by students performing open ovariectomy, when assisted by an experienced surgeon. Overall, the results provided proof of concept regarding the feasibility of having expert surgeons train veterinary students in basic laparoscopic tasks and laparoscopic ovariectomy procedures.
Although encouraging, these results should prompt further research to determine best practices for implementing laparoscopic training in a veterinary curriculum, verify patient safety in a larger study population, and assess the impact of the outcomes of these skills on graduating students.
ABBREVIATIONS
| MISTELS | McGill Inanimate System for Training and Evaluation of Laparoscopic Skills |
| OSATS | Objective Structured Assessment of Technical Skills |
Random.org. True random number service. Available at: www.random.org. Accessed Dec 4, 2011.
Introduction to small animal laparoscopy (video), Karl Storz Veterinary Endoscopy, Goleta, Calif.
Laparoscopic spays in dog and cats (video), Karl Storz Veterinary Endoscopy, Goleta, Calif.
Laparoscopic Surgery Standard Set, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Szabo-Berci-Sackier laparoscopy trainer, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
LYRA laparoscopic simulator, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Pegboard, Simulab Corp, Seattle, Wash.
Clickline Duval grasper forceps, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Curved Metzenbaum scissors 5 × 36 mm, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Laparoscopy bipolar vessel-sealing and cutting device, Olympus Surgical Technologies America, Maple Grove, Minn.
Amber natural latex tubing 1/8 inch, catalog No. 011RA, Prime-line Industries, Akron, Ohio.
Copies of the questionnaire and the surgery scoring rubrics as well as training laboratory details for the open and laparoscopic surgeries are available from the corresponding author on request.
Endoflator, 20 L, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Verres needle, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Cannula, Termanian, Endotip, 6 mm, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Cannula, Termanian, Endotip, 11 mm, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Babcock grasper and clickline, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
Ovarian J hook needle, on loan courtesy of Karl Storz Veterinary Endoscopy, Goleta, Calif.
References
1. Greenfield CL, Johnson AL, Schaeffer DJ. Frequency of use of various procedures, skills, and areas of knowledge among veterinarians in private small animal exclusive or predominant practice and proficiency expected of new veterinary school graduates. J Am Vet Med Assoc 2004; 224: 1780–1787.
2. Hill LN, Smeak DD, Lord LK. Frequency of use and proficiency in performance of surgical skills expected of entry-level veterinarians by general practitioners. J Am Vet Med Assoc 2012; 240: 1345–1354.
3. Smeak DD, Hill LN, Lord LK, et al. Expected frequency of use and proficiency of core surgical skills in entry-level veterinary practice: 2009 ACVS Core Surgical Skills Diplomate Survey results. Vet Surg 2012; 41: 853–861.
4. Mayhew PD, Brown DC. Comparison of three techniques for ovarian pedicle hemostasis during laparoscopic-assisted ovariohysterectomy. Vet Surg 2007; 36: 541–547.
5. Adin CA. Complications of ovariohysterectomy and orchiectomy in companion animals. Vet Clin North Am Small Anim Pract 2011; 41: 1023–1039.
6. Kennedy KC, Tamburello KR, Hardie RJ. Peri-operative morbidity associated with ovariohysterectomy performed as part of a third-year veterinary surgical-training program. J Vet Med Educ 2011; 38: 408–413.
7. Devitt CM, Cox RE, Hailey JJ. Duration, complications, stress, and pain of open ovariohysterectomy versus a simple method of laparoscopic-assisted ovariohysterectomy in dogs. J Am Vet Med Assoc 2005; 227: 921–927.
8. Leminen A. Comparison between personal learning curves for abdominal and laparoscopic hysterectomy. Acta Obstet Gynecol Scand 2000; 79: 1100–1104.
9. Lansdowne JL, Mehler SJ, Boure LP. Minimally invasive abdominal and thoracic surgery: techniques. Compend Contin Educ Vet 2012; 34: E2.
10. Fransson BA, Ragle CA. Assessment of laparoscopic skills before and after simulation training with a canine abdominal model. J Am Vet Med Assoc 2010; 236: 1079–1084.
11. Fransson BA, Ragle CA, Bryan ME. A laparoscopic surgical skills assessment tool for veterinarians. J Vet Med Educ 2010; 37: 304–313.
12. Lansdowne JL, Mehler SJ, Boure LP. Minimally invasive abdominal and thoracic surgery: principles and instrumentation. Compend Contin Educ Vet 2012; 34: E1.
13. Fraser SA, Klassen DR, Feldman LS, et al. Evaluating laparoscopic skills: setting the pass/fail score for the MISTELS system. Surg Endosc 2003; 17: 964–967.
14. Vassiliou MC, Dunkin BJ, Marks JM, et al. FLS and FES: comprehensive models of training and assessment. Surg Clin North Am 2010; 90: 535–558.
15. Dauster B, Steinberg AP, Vassiliou MC, et al. Validity of the MISTELS simulator for laparoscopy training in urology. J Endourol 2005; 19: 541–545.
16. Derossis AM, Antoniuk M, Fried GM. Evaluation of laparoscopic skills: a 2-year follow-up during residency training. Can J Surg 1999; 42: 293–296.
17. Peters JH, Fried GM, Swanstrom LL, et al. Development and validation of a comprehensive program of education and assessment of the basic fundamentals of laparoscopic surgery. Surgery 2004; 135: 21–27.
18. Vassiliou MC, Ghitulescu GA, Feldman LS, et al. The MISTELS program to measure technical skill in laparoscopic surgery: evidence for reliability. Surg Endosc 2006; 20: 744–747.
19. Fried GM, Feldman LS, Vassiliou MC, et al. Proving the value of simulation in laparoscopic surgery. Ann Surg 2004; 240: 518–525.
20. Sroka G, Feldman LS, Vassiliou MC, et al. Fundamentals of laparoscopic surgery simulator training to proficiency improves laparoscopic performance in the operating room—a randomized controlled trial. Am J Surg 2010; 199: 115–120.
21. McCluney AL, Vassiliou MC, Kaneva PA, et al. FLS simulator performance predicts intraoperative laparoscopic skill. Surg Endosc 2007; 21: 1991–1995.
22. Goff BA, Lentz GM, Lee D, et al. Development of an objective structured assessment of technical skills for obstetric and gynecology residents. Obstet Gynecol 2000; 96: 146–150.
23. Lentz GM, Mandel LS, Goff BA. A six-year study of surgical teaching and skills evaluation for obstetric/gynecologic residents in porcine and inanimate surgical models. Am J Obstet Gynecol 2005; 193: 2056–2061.
24. Martin JA, Regehr G, Reznick R, et al. Objective structured assessment of technical skill (OSATS) for surgical residents. Br J Surg 1997; 84: 273–278.
25. Fransson BA, Ragle CA, Bryan ME. Effects of two training curricula on basic laparoscopic skills and surgical performance among veterinarians. J Am Vet Med Assoc 2012; 241: 451–460.
26. De Win G, Van Bruwaene S, De Ridder D, et al. The optimal frequency of endoscopic skill labs for training and skill retention on suturing: a randomized controlled trial. J Surg Educ 2013; 70: 384–393.
27. Scott DJ, Ritter EM, Tesfay ST, et al. Certification pass rate of 100% for fundamentals of laparoscopic surgery skills after proficiency-based training. Surg Endosc 2008; 22: 1887–1893.
28. Olsen D, Bauer MS, Seim HB, et al. Evaluation of a hemostasis model for teaching basic surgical skills. Vet Surg 1996; 25: 49–58.
29. Griffon DJ, Cronin P, Kirby B, et al. Evaluation of a hemostasis model for teaching ovariohysterectomy in veterinary surgery. Vet Surg 2000; 29: 309–316.
30. Culp WT, Mayhew PD, Brown DC. The effect of laparoscopic versus open ovariectomy on postsurgical activity in small dogs. Vet Surg 2009; 38: 811–817.
31. Fahie MA. Chapter 75: primary wound closure. In: Tobias KM, Johnston SA, eds. Veterinary surgery: small animal. St Louis: Elsevier, 2012;1197–1209.
32. Dupre G, Fiorbianco V, Skalicky M, et al. Laparoscopic ovariectomy in dogs: comparison between single portal and two-portal access. Vet Surg 2009; 38: 818–824.
33. Gumbs AA, Hogle NJ, Fowler DL. Evaluation of resident laparoscopic performance using global operative assessment of laparoscopic skills. J Am Coll Surg 2007; 204: 308–313.
34. Subramonian K, DeSylva S, Bishai P, et al. Acquiring surgical skills: a comparative study of open versus laparoscopic surgery. Eur Urol 2004; 45: 346–351.
35. Hausknecht JP, Halpert JA, Di Paolo NT, et al. Retesting in selection: a meta-analysis of coaching and practice effects for tests of cognitive ability. J Appl Psychol 2007; 92: 373–385.
36. Barrera JS, Monnet E. Effectiveness of a bipolar vessel sealant device for sealing uterine horns and bodies from dogs. Am J Vet Res 2012; 73: 302–305.
37. Perkins N, Starkes JL, Lee TD, et al. Learning to use minimal access surgical instruments and 2-dimensional remote visual feedback: how difficult is the task for novices? Adv Health Sci Educ Theory Pract 2002; 7: 117–131.
38. Kolozsvari NO, Kaneva P, Brace C, et al. Mastery versus the standard proficiency target for basic laparoscopic skill training: effect on skill transfer and retention. Surg Endosc 2011; 25: 2063–2070.
