Laparoscopic hysterectomy is a commonly performed procedure. However, one high-risk complication is vaginal cuff dehiscence. Currently, there is no standardization regarding thread material or suturing technique for vaginal cuff closure. Therefore, this study aimed to compare extracorporeal and intracorporeal suturing techniques for vaginal cuff closure using a pelvic trainer model. Eighteen experts in laparoscopic surgery performed vaginal cuff closures with interrupted sutures using intracorporeal knotting, extracorporeal knotting and continuous, unidirectional barbed sutures. While using an artificial tissue suturing pad in a pelvic trainer, experts performed vaginal cuff closure using each technique according to block randomization. Task completion time, tension resistance, and the number of errors were recorded. After completing the exercises, participants answered a questionnaire concerning the suturing techniques and their performance. Experts completed suturing more quickly (p < 0.001, p < 0.001, respectively) and with improved tension resistance (p < 0.001, p < 0.001) when using barbed suturing compared to intracorporeal and extracorporeal knotting. Furthermore, the intracorporeal knotting technique was performed faster (p = 0.04) and achieved greater tension resistance (p = 0.023) compared to extracorporeal knotting. The number of laparoscopic surgeries performed per year was positively correlated with vaginal cuff closure duration (p = 0.007). Barbed suturing was a time-saving technique with improved tension resistance for vaginal cuff closure.

Study design

We conducted a prospective, randomized controlled study at the University Hospital Basel from the 1^st November 2021 to 30^th April 2022. Eighteen participants were randomized in block randomizations of three. All participants performed interrupted intracorporeal, extracorporeal, and continuous barbed suturing for VCC using each technique according to their randomization. For the primary endpoint, the time required to complete a task was recorded during each participant’s performance. Following the task, the secondary endpoints (i) precision, (ii) knot strength, (iii) cuff closure spreadability, and (iv) number of mistakes made were measured. Before and after completing the tasks, participants were given questionnaires. The first asked about their background and the second about their experience while completing the exercises. (Figure 1). 

Power analysis

The required sample size was estimated using a power analysis, calculated based on two-sided, paired t-tests with power set to 90% and the significance level at 0.05. While a minimum of 18 subjects was indicated, the statistical distribution of the task duration time was unknown and, therefore, the calculation was a pragmatic approximation. 

Study population

In total, 18 experts were successfully recruited with a dropout rate of zero, and 54 measurements were obtained. Qualifying as an expert required one to be a surgeon with more than five years of operative experience and more than thirty laparoscopic interventions per year. Study participants were recruited from one tertiary and three secondary hospitals.

All methods were carried out in accordance with the CONSORT statement guidelines. A formal IRB certification of exemption (Req-2021-01075) was provided by the ethics committee of Northwest and Central Switzerland (EKNZ) on September 22, 2021, which confirmed that the research project fulfilled the general ethical and scientific standards for research with human subjects. All participants gave their written, informed consent to participate in the study. The anonymization of personal data was guaranteed.

Instrument set-up

All exercises were carried out on a box trainer. An endoscopy tower was equipped with a 24-inch monitor and a 300 W Xenon light source (Karl Storz SE & Co., Tuttlingen, Germany) and a Storz Hopkins II, 10 mm, 0° telescope with a Xenon Nova 300 light source and an Image 1 H3-Z Full HD camera (Karl Storz SE & Co., Tuttlingen, Germany) were used. Two access points equivalent to the lateral ancillary trocar entry points were used for the instruments. Two needle holders (Geyl Medical 801.023), laparoscopic scissors, and a closed jaw type knot pusher (Karl Storz 26596 D closed jaw end) were used.

Exercises

The colpotomy model was made of mesh-augmented silicone with a similar shape and size as a real colpotomy and was set up on the posterior wall of the box trainer. A brief instructional video showed the three different suturing techniques. After a short individual warm-up (20 minutes maximum) the experts began the different suturing techniques according to their randomization, completing one run per suture type for three runs in total. 

A. Vaginal cuff closure with intracorporeal interrupted suturing 

Suture A was a closure technique using three interrupted figure-eight sutures and intracorporeal knotting with a polyfilament thread (Vicryl, polyglactin 910, Johnson & Johnson). These three sutures were performed with a surgeon’s knot, which translated to securing the knot with three loops. (Video 1).

B. Vaginal cuff closure with extracorporeal interrupted suturing

Suture B used the same closure technique as suture A but with knotted extracorporeal polyfilament thread (Vicryl, polyglactin 910, Johnson & Johnson). The three interrupted figure-eight sutures were performed with a surgeon’s knot. The tightening of the knots was made with one hand and tightened with a knot pusher (Video 2).

C. Vaginal cuff closure with barbed continuous suturing

Suture C was a continuous, unidirectional barbed suture made with V-Loc™ (180 Absorbable Wound Closure Device; Covidien, Mansfield, MA, USA). This suture was made unidirectional. Thus, after the first stitch, the thread was pulled through the loop. After 5 more stitches from right to left, the thread was cut at the end of the colpotomy without extra anchoring stitches. (Video 3).

Questionnaires

Participants answered questionnaires before and after the exercises. The questionnaire given before the exercises concerned general participant characteristics including sex, age, whether and how often they played video games, what types of sports and instruments they played, and their background regarding surgical and technical skills. After completing the exercises, participants answered a questionnaire regarding how they felt, both mentally and physically, about their experience with the different suturing techniques. 

Statistical analyses

Descriptive statistics are presented as counts and frequencies for categorical data. For metric variables, means with standard deviations, medians, and interquartile ranges were used. Linear mixed-effects models were used to predict spreading capacity with technique and run as predictor variables. Results are presented as mean differences. For total run time and changes in knot strength, the variables were log-transformed, and the results presented as geometric mean ratios. A p-value <0.05 was considered significant. The statistical software R (version 4.1.3) was used for the analyses.