Board 409 - Research Abstract Simulating Azygos Vein Ligation - Deliberate Practice is Invaluable (Submission #1187)

Abstract

Introduction/Background General Surgery (GS) residents painstakingly learn to ligate vessels in continuity. Swift and skillful knot tying in the chest is a particular challenge to the burgeoning thoracic surgeon. We sought to assess baseline proficiency in ligating the azygos vein within a simulated chest among GS interns, medical students and thoracic surgery staff. Methods A low-fidelity chest model was constructed in the left lateral decubitus position using cardboard (scapula, ribs and chest wall), fabric (skin, subcutaneous tissue, muscle, fascia, esophagus, vagus and intercostal nerves, lung, mediastinal pleura and superior vena cava) and a 10 mL water filled balloon (azygos vein). GS interns (n = 34), medical students (n = 4) and thoracic surgery staff (n = 2) were asked to ligate the azygos vein in continuity through an eight cm diameter thoracotomy with a depth of 20 cm using 2-0 silk ligatures. Of the 40 participants, only staff surgeons had prior thoracic knot tying training. Scores were based on a 20-point grading scale including task completion, timing and completeness of lumen occlusion. Participants were surveyed anonymously and asked to rate degree of model realism, enjoyment and educational benefit using a 5-point Likert scale (1= strongly disagree, 5= strongly agree). Results Thirty nine of 40 trainees completed the task. The mean score for GS interns was 9.2 (range 3–16, SD = 2.7), medical students 8.5 (range 5-10, SD 2.3, p = 0.54) and thoracic surgeons 18 (SD 0, p = 0.03). Mean task completion times among residents and medical students were slow (133 vs 132 seconds respectively). Staff surgeons were faster (mean = 36 seconds, p = 0.02). Proximal or distal azygos vein stump leaks of any kind occurred in 20% (13/68) of surgical resident veins, 38% (3/8) of medical student veins and none for staff. When azygos stumps were subjected to a force of 22.5N, 33% (4/12) of initial drip leaks worsened to unimpeded flow among surgical residents. Of the veins initially without leak, 2% (1/50) progressed to a detectable drip while 4% (2/50) progressed to unimpeded flow among surgical residents when stump force was applied. Survey response was 80%. Mean Likert scores for usefulness in teaching thoracic knot tying (4.6), utility in learning to tie in other difficult anatomic locations (4.6) and enjoyability (4.2) rated the highest. Trainees and staff felt that the model was acceptable with regards to realism (3.8) and usefulness as a practice tool (4.0). Conclusion This low-fidelity simulator is able to separate novice thoracic knot tiers from experienced surgeons. Participants validate its usefulness as a teaching tool with favorable response. This study further exposes the need for deliberate practice among young trainees. Disclosures None.