Surgical performance of large loop excision of the transformation zone in a training model: A prospective cohort study

Abstract

Large loop excision of the transformation zone (LLETZ) is one of the most common procedures in operative gynecology and it is a routine part of the surgical training program of residents. There is, however, no established and standardized method of teaching residents how to perform LLETZ. Here, we present a surgical training model and assessed the improvement of surgical skills during repeated hands-on trainings of LLETZ in this model.Surgical novices and experts were recruited and were shown a LLETZ training video and then performed 3 LLETZ training sessions on consecutive days. Surgical skills were assessed by Objective Structured Assessment of Technical Skills (OSATS). Global rating scale (GRS), confidence (CON), fragmentation rate (FR), performance time (PT), and OSATS scores were calculated. Intra- and interobserver variabilities were determined. The construct validity of OSATS was assessed comparing metric scores of novices with those of experts.Sixty-eight probands (58 novices, 10 experts) were recruited. GRS, 2.3 ± 1.3 (median ± SD) versus 1.4 ± 0.6, P < .001; CON, 2.7 ± 0.9 versus 1.6 ± 0.6, P < .001; FR, 81% versus 100%, P < .001; PT, 152 ± 33 versus 120 ± 27 seconds, P = .006; and OSATS scores, 18.8 ± 1.3 versus 19.1 ± 1.1, P = .16 of novices improved from session 1 to session 3. OSATS showed construct validity with metric scores (GRS, 1.1 ± 0.3 vs 2.3 ± 0.8, P < .001; CON, 1.0 ± 0.0 vs 2.7 ± 0.9, P < .001; PT 125 ± 30 vs 152 ± 33 seconds, P = .02; OSATS scores, 19.6 ± 0.7 vs. 18.8 ± 1.3, P = .02) reliably discriminating between experts and novices. Intra- and interobserver variabilities across probands were 0.99 ± 0.03 and 0.64 ± 0.10, respectively. OSATS scores were independent of handedness, sex, and regular sports activity in univariate and multivariate analyses.Repeated hands-on trainings improve surgical performance of LLETZ in a surgical training model with construct validity.

Figure 1

Diagram of the proband flow through the study.

Figure 2

Training model. A, The model in use during a training session with gynecology residents. B, Close-up view of the model with an approx. 3-cm-diameter sausage representing the cervix with an “acetowhite lesion” (painted with white correction fluid), accessible through a cup representing the vagina held open by a speculum, and grasped with forceps. C, Schematic drawings of the model. The enclosure is made from a rigid plastic container. A hole is cut into the bottom and fitted with an inwall socket whose bottom was also cut out. Velcro strip are fastened to the sides of the enclosure and a hole is drilled in the side to mount a fitting for a vacuum line to suck out fumes. The “vagina” is detachable to facilitate access and cleaning (it will become quite greasy), and is made from 2 plastic cups (bottoms cut out) with Velcro strips glued in between the cups (aligned to fit the strips on the outer enclosure) and a matching hole for the fume exhaust. Two types of sausages are used: a large (approx. 9–10 cm diameter) support sausage, to which the return electrode is attached, and a smaller type of sausage with approx. 3 cm diameter that represents the cervix and is tightly inserted into a cavity scooped from the support sausage (conductivity between the sausages must be ensured). The sausage assembly is inserted from the back end of the rigid enclosure and both are fastened to a support stand using Velcro strips. After each procedure, the “vagina” is detached and the “cervix” can easily be replaced with a new one. The support sausage can be used for many procedures over several days when kept in a refrigerator in between sessions.

Figure 3

Main results. Total Objective Structured Assessment of Surgical Skills (OSATS) score, performance time (PT; in seconds), global rating scale (GRS) and confidence (CON) of the expert group (E) and the novices at training sessions 1, 2, and 3 (N1–3) are shown; numbers in parentheses indicate the number of probands. Box plots: thick lines indicate medians, boundaries, whiskers, and filled circles the 25th/10th/5th and the 75th/90th/95th percentiles, respectively; in case of the experts (N = 10), the medians and ranges are indicated instead. White circles are means, lines between N1-N3 show linear regressions through the means. Statistical significant differences between groups (Mann–Whitney U test; PT: t test) or over time (Wilcoxon signed rank test; PT: paired t test) are indicated by brackets within panels (in case of GRS/CON also vertical lines connecting panels); levels of significance are as follows: ^∗, P < .05; ^∗∗, P < .01; ^∗∗∗, P ≤ .001.

Figure 4

Intra- and interobserver variabilities. Agreement score (solid lines; as described in the methods section) and Fleiss’ kappa (dotted lines) are shown broken down by each of the 20 Objective Structured Assessment of Surgical Skills (OSATS) score items, global rating scale (GRS), and confidence (CON) (panel A) and by proband (panel B).