Chest tube fixation strength depends on suture caliber and fixation technique rather than tube diameter: a biomechanical cadaver study

BACKGROUND: Chest tube dislodgement remains a relevant complication in emergency, trauma, and intensive care medicine. In a previous biomechanical study, the Modified Johannesburg technique using Mersilene USP 1 demonstrated superior fixation strength compared with other chest tube fixation techniques. The present study aimed to determine whether suture size, suture material, and chest tube diameter influence fixation strength. METHODS: A prospective interventional biomechanical cadaveric study was performed using fresh porcine thoracic wall specimens. A total of 320 load-to-failure tests were conducted under standardized laboratory conditions. Two fixation techniques, Modified Johannesburg and Purse String, were compared using two chest tube diameters (20/28 Ch) and four non-absorbable braided suture configurations: Mersilene USP 1, Mersilene USP 2 - 0, Silk USP 1, and Silk USP 2 - 0. Each experimental group consisted of 20 specimens. Specimens were tested in a uniaxial testing machine until construct failure. Force [N] and elongation [mm] at failure were measured. The experiments were videotaped, and the failure mechanism was analyzed. RESULTS: The Modified Johannesburg technique demonstrated significantly higher pull-out forces compared to the Purse String technique (125.0 vs. 66.4 N; p < 0.001), as did larger suture sizes (USP 1 vs. 2 - 0; p < 0.001) and Mersilene compared to Silk (114.6 vs. 76.9 N; p < 0.001). Chest tube size had only a very small and inconsistent effect on pull-out strength. The predominant failure mode was suture rupture (94.7%). CONCLUSIONS: Chest tube fixation strength is significantly influenced by fixation technique, suture size, and suture material. The effect of chest tube diameter on fixation strength appeared negligible. The Modified Johannesburg technique, size 1 sutures, and Mersilene material provided superior biomechanical stability. Since failure occurred predominantly by suture rupture, the suture appears to represent the weakest link of the fixation construct.