A novel small animal ovariohysterectomy training model improves veterinary students' surgical times

Abstract

The aim of this study was to evaluate the impact of a novel, low‐cost ovariohysterectomy (OVH) training model on surgical times recorded for final‐year veterinary students performing live canine and feline OVH. The training model provides focused practice on a segment of the OVH procedure that is typically challenging for students: the exteriorisation of an ovary with clamping and ligation of the ovarian pedicle. At James Cook University, surgical times are recorded as part of routine patient care and include the time from the start of an abdominal incision to exteriorisation of a uterine horn, the time taken to ligate both ovarian pedicles and the uterine body, the time taken to complete abdominal closure and the total procedure time. For this study, surgical times recorded during canine and feline OVHs performed by a full‐year cohort of students trained before the introduction of the OVH model (Pre‐model group; n = 79 students) were compared to a full‐year cohort trained after the introduction of the OVH model (Post‐model group, n = 80 students). All surgical times recorded for canine OVH were significantly reduced in the Post‐model group compared to the Pre‐model group. For feline OVH, surgical times were similar, except for a significant reduction in the time taken to ligate both ovarian pedicles and the uterine body in the Post‐model group. An unanticipated finding was significant improvements in surgical times for successive students performing canine OVH over the course of each cohort's year, likely a reflection of developing student competence and confidence across the clinical year.

The use of training models in veterinary surgical education has increased exponentially in recent years, ¹ with multiple benefits recognised, including a reduced need for live animals for student training, as well as improved student wellbeing through opportunities to practice surgical skills repeatedly, within a low stakes environment. ² Moreover, improved student preparation through practice on models has been shown to decrease patients' postoperative pain ³ and may shorten surgical times ⁴ in subsequent live animal surgeries.

In contrast to other ovariohysterectomy (OVH) training models that simulate the entire OVH procedure, from abdominal incision to the placement of skin sutures, ³ , ⁴ , ⁵ , ⁶ , ⁷ , ⁸ , ⁹ the novel surgical training model developed at James Cook University (JCU) targets repetitive practice at a single challenge point. Within our school, students are taught a single‐clamp method for isolating and ligating the ovarian pedicle, as opposed to the traditional “three‐clamp technique”. For the single clamp technique, a clamp is placed below the ovary, after which significant finger dexterity is required to hold the clamp above the abdominal incision while simultaneously placing a ligature on the ovarian pedicle, at sufficient distance below the clamp to ensure adequate tissue constriction and haemostasis. In response to perceived difficulties by students with this component of the OVH procedure, the low‐cost training model was developed (Figure 1). The model consists of a section of polyvinyl chloride (PVC) pipe with a window cut‐out, containing elastic bands to mimic the suspensory ligament, ovarian artery (and vein) and the uterus. A bead inside a ball of cotton wool represents the ovary. Traction on the ovary allows the student to practice clamping and ligation of the ovarian pedicle. The aim of this study was to evaluate the effect of this model as a teaching tool, by comparing surgical times recorded during live OVH surgeries by an entire year‐cohort of students that had not been exposed to the model during presurgical preparation (Pre‐model cohort, n = 79 students) to an entire year‐cohort trained after introduction of the model for presurgical preparation (Post‐model cohort; n = 80 students). To the best of our knowledge, the teaching approach in preparation for live surgeries was otherwise identical for both cohorts.

Figure 1.

The ovariohysterectomy training model developed at James Cook University for veterinary student preparation before live animal surgical training. The model consists of a section of PVC pipe with a dorsal cut‐out, rubber bands to mimic the tension present in the ovarian pedicle and a small ball of cotton wool with a bead inside to represent the ovarian bursa and ovary.

Tutor‐supported, live animal OVH surgeries are currently performed at the JCU student spey clinic during the final year of the Bachelor of Veterinary Science (BVSc) curriculum. Students round off their surgical training by performing an OVH on a female dog and, if available, a female cat. Animals requiring desexing surgery are provided by a local animal foster and rehoming organisation. During OVH procedures, surgical times are routinely recorded as part of patient care and the ongoing monitoring of teaching practices and student outcomes. Times recorded include the time from the start of an abdominal incision to exteriorisation of a uterine horn, the time taken to ligate both ovarian pedicles and the uterine body, the time taken to complete abdominal closure and the total procedure time. Ethical approval to use these data, retrospectively, was granted by the JCU Human Research Ethics Committee (25H‐0012). Statistical analyses were performed using IBM SPSS version 29 (Chicago, IL, USA), with significance set at 5%.

The Mann–Whitney U test was used to compare the median ages and weights of dogs and cats undergoing OVH by students in the Pre‐model and Post‐model cohorts (Table 1). The median age of dogs undergoing surgery in the hands of the Pre‐model cohort was one month higher than the median age of those undergoing surgery by the Post‐model cohort (P = 0.04, Table 1), whereas the median age of cats was similar for both groups. The median weights of dogs and cats were marginally higher for the Pre‐model cohort than the Post‐model cohort, although this difference was only statistically significant for cats (Table 1). Annandale et al. ⁴ found that surgical times tended to be positively correlated to body weight in both dogs and cats. Analysis of our data showed that higher body weight correlated to increased total procedure time in dogs (r _s [157] = 0.337, P < 0.001), but not cats (r _s [136] = 0.129, P = 0.131).

Table 1.

Comparison of median animal age, animal weight and student surgical times for dogs and cats undergoing ovariohysterectomy (OVH) by fifth year veterinary science students within full year cohorts, before (Pre‐model, n = 79 students) and after (Post‐model, n = 80 students) the introduction of a novel surgical training model

	Dogs			Cats
	Pre‐model*	Post‐model	P‐value	Pre‐model	Post‐model	P‐value
Number of animals undergoing OVH	79	80	‐	74	64	‐
Median age in months (range)	7a (5–72)	6b (4–48)	0.040	5 (3–24)	5 (3–24)	0.682
Median weight in kg (range)	18.3 (4.8–43.6)	17.2 (4.5–33.5)	0.554	2.7a (1.5–3.9)	2.4b (1.6–3.7)	0.004
Median time from start of abdominal incision to exteriorisation of uterus (min)	13a	9b	<0.001	10	9	0.093
Median time to complete ligation of both ovarian pedicles and uterine body (min)	68a	56b	<0.001	33.5a	31b	0.039
Median time to complete abdominal closure (min)	57a	54.5b	0.025	47	45	0.099
Median total procedure time (min)	150a	119b	<0.001	92	85.5	0.066

Differing superscripts indicate a significant difference for that species.

The Mann–Whitney U test was also used to compare surgical times between cohorts (Table 1). The median total procedure time for canine OVH decreased by 31 min (P < 0.001) following introduction of the OVH model. The time to complete ligation of both ovarian pedicles and the uterine body contributed substantially to this improvement, with the median time for this component decreasing by 12 min between the Pre‐model and Post‐model cohorts (P < 0.001). Given that the training model provides focused practice on the clamping and ligation of an ovarian pedicle, these findings affirm improved student preparation for this component. Improvements were also seen in the times taken from the start of an abdominal incision to exteriorisation of the uterus, as well as the time to complete abdominal closure, within the canine OVH dataset. Given that these components were not specifically targeted by the OVH model, reasons behind these improvements remain speculative. It is possible that the OVH model encouraged better presurgical preparation by students ¹⁰ or improved students' surgical confidence more generally. In addition, some other unidentified difference in teaching approach between groups, or an inherent difference in students' surgical abilities, cannot be ruled out.

For feline OVH, the effect of the OVH model was less pronounced than for canine OVH. Although the median total procedure time for cats was 6.5 min lower in the Post‐model cohort than the Pre‐model cohort, this difference was not significant (P = 0.066). Interestingly, the only component that did show a statistically significant improvement in cats was the time to complete ligation of both ovarian pedicles and the uterine body (P = 0.039), which correlates with the focal point of the JCU OVH model. These results are similar to the findings of a previous study, ⁴ where an OVH training model improved total surgical times for canine OVH (for students with no prior surgical experience) but not for cats. As discussed in that study, feline OVH is widely accepted as less challenging than canine OVH due to inherent anatomical differences between the species, which may explain the smaller gains achieved through the use of training models.

Figure 2 shows surgical times recorded during canine and feline OVH surgeries, performed by successive students within the Pre‐model and Post‐model cohorts. Visual inspection of these graphs suggests improvements in students' surgical performance over the course of the clinical year of the BVSc curriculum. For each student cohort, linear regression was used to explore this, that is, to assess whether students who completed their OVH surgery later in the year performed better than those who completed their OVH surgery earlier in the year. For the Pre‐model cohort, total procedure time decreased by 0.78 minutes for each successive canine OVH performed in the JCU student spey clinic over the year (F[1, 77] = 17.95, P < 0.001). For the Post‐model cohort, total procedure time decreased by 0.50 minutes for each successive canine OVH performed in the clinic over the year (F[1, 78] = 9.827, P = 0.002). For feline OVH, no significant change in performance occurred over the course of the year in the Pre‐model cohort. However, for the Post‐model group, total procedure time decreased by 0.42 min for each successive feline OVH performed in the clinic (F[1, 62] = 14.72, P < 0.001). These encouraging results may reflect improvements in student confidence and competence over the final year of their veterinary training, as a result of expanding clinical experience. ¹¹ Also, students on surgical rotation in the JCU spey clinic later in the year may be more likely to have had some form of surgical practice during clinical rotations and external placements than those on rotation earlier in the year.

Figure 2.

Surgical times recorded for successive students within a full‐year cohort performing canine and feline ovariohysterectomy surgeries, either before (Pre‐model cohort) or after (Post‐model cohort) the introduction of a novel surgical model developed at James Cook University.

A failure to capture individual students' prior surgical experience is a major limitation of this study. In addition, student demographic details were not available for use in this study. Furthermore, students were not randomised into study groups, in common with similar studies. ³ However, the use of data collected during the training of two entire class cohorts provided both a relatively high sample size and distributed sampling across two full years, making the groups more likely to be comparable.

A further limitation of this study was that the degree to which individual students in the Post‐model cohort engaged with the model was not recorded; such data would be useful to better understand the model's teaching value. Previous studies on OVH training models have frequently utilised a student questionnaire. ⁴ , ⁵ , ⁶ , ⁸ , ⁹ , ¹⁰ , ¹² Although questionnaire responses would have been an interesting addition to this study, the use of routine data collected before conceptualisation of this study implies that no group of students was deliberately favoured above any others. In addition, this approach eliminated the risk of unconscious biases from either staff or students, including, for example, the Hawthorne effect, which is a phenomenon whereby study participants’ performance improves due to awareness of the study. ¹³

The model described in the current study is low‐cost and, visually, of low fidelity. Read et al. ⁷ found that a high fidelity OVH model provided marginal benefit over a low‐fidelity model. The results of the current study support the use of training models, including low‐cost designs, for student preparation before live animal surgeries. For veterinary schools where small animal OVH is taught using a single‐clamp technique for ligation of the ovarian pedicle, this model can be easily reproduced and may provide a useful addition to students' presurgical preparation.

Conflicts of interest and sources of funding

The authors declare no conflicts of interest or sources of funding for the work presented here.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.