Y. Hu1, I. A. Le1, R. N. Goodrich1, K. D. Brooks1, B. L. Edwards1, J. R. Gillen1, A. T. Schroen1, P. W. Smith1, S. K. Rasmussen1 1University Of Virginia,Surgery,Charlottesville, VA, USA
Introduction: Simulation training facilitates operative teaching while safeguarding patient safety. However, a cost-effective model for open vessel ligation does not exist. We hypothesized that a durable vessel ligation simulator that effectively evaluates and instructs junior trainees can be constructed and implemented for less than 100 USD.
Methods: VesselBox was designed to simulate vessel ligation using expired surgical gloves as surrogate vessels. Construction cost was 30 USD; flexible cost was 0.17 USD per ligation. Model construct validity was previously demonstrated through assessments of students, residents, and faculty. To assess model effectiveness, graduating fourth-year medical students were video-recorded while performing ligations using VesselBox. These pre-test recordings were evaluated by three blinded surgical faculty using the Objective Structured Assessments of Technical Skills global rating scale (GRS) and a task-specific checklist. Subsequently, each student was trained using VesselBox in an adaptive practice session tailored to learning speed through cumulative sum. Lastly, post-tests were performed on fresh human cadavers and assessed with blinding toward pre-test results. Inter-rater correlation was assessed by Spearman’s correlation coefficient, and changes in proficiency were measured using the signed rank sum test.
Results: Among 16 students, pre-test scores averaged 2.29 out of 5 for the GRS (interquartile range, IQR 2.01-2.5) and 4.83 out of 8 for the task-specific checklist (IQR 4.17-6.33). Pre-test inter-rater correlation for the two metrics were 0.92 (p < 0.001) and 0.67 (p = 0.025), respectively. VesselBox practice sessions averaged 21.8 min per participant (IQR 19.5 – 27.7), and consisted of between 8 and 13 ligation repetitions. Average training cost was 1.87 USD per participant. Post-tests demonstrated skill transferability and improvement, as measured by both GRS (3.23 vs 2.29, p < 0.001, Figure 1A) and checklist metrics (7.33 vs 4.83, p < 0.001, Figure 1B). Median speed improved from 128.2s to 97.5s per ligation (p = 0.001).
Conclusions: VesselBox is an innovative, cost-effective model for open vessel ligation. Ideally suited for graduating medical students and junior surgical residents, VesselBox has proven utility in both evaluative and practice settings. In the interest of patient safety, simulators for open surgical skills should be used to certify baseline proficiency in a pre-clinical setting.
