DS09 An exploratory biomechanical experiment comparing the ultimate tensile strength of 10 suturing techniques including a novel suture utilized in high-tension closure

Abstract Dermatological surgeons may experience difficulty in managing surgical defects at high-tension sites such as the scalp, back or legs. Existing useful high-tension suture techniques for closure include the horizontal mattress, single- or double-loop mattress, the pulley, tandem pulley, and other strategies to aid closure, including the use of a towel clamp for mechanical creep. The use of twisting loops in suturing techniques is rarely reported and to the best of our knowledge they are not widely used in dermatological surgery. The ultimate tensile strength (UTS) is the maximum amount of stress a material can withstand before breaking point. Collaborating with a biomedical engineering research group, we compared the UTS of 10 suture techniques used in skin surgery. These included looped vs. nonlooped suture technique variants, and twisted and nontwisted variants of a novel triple-loop mattress suture. Sutures were used on porcine tissue samples with perpendicular wound opposition, with UTS measured using a tensometer machine (N = Newtons) to determine the range of UTS between suture techniques. We also assessed the difference in UTS when performing twisted and nontwisted arrangements of the same technique. Sutures were tested once and performed on porcine tissue samples (approximately 22 × 18 cm), with an 8-cm incision placed at the same location within each specimen. Samples had variable tissue depth (approximately 3 cm), and although there were difficulties in achieving standardized specimens, this reflected the real-world variability in tissue composition. The tandem pulley sustained the highest UTS of all techniques (181 N). The novel twisted triple-loop mattress suture (77 N) withstood five times the UTS of a simple interrupted suture (16 N). The nontwisted triple-loop mattress suture had a UTS of 70 N. Twisting of loops compared with nontwisted versions of the same suture techniques yielded a 7–12-N range of higher tensile strength, suggesting added benefit in high-tension sites. Other results included the twisted single-loop mattress suture (84 N) vs. nontwisted single-loop mattress suture (72 N), double-loop mattress (84 N), pulley (101 N), horizontal mattress (92 N) and vertical mattress (53 N). We have utilized the novel triple-loop mattress suture (including twisted vs. nontwisted loop variants) in five patients requiring high-tension closure on the scalp and back, with good scar cosmesis (mean Patient and Observer Scar Assessment Scale score 2 out of 10). We suggest that the novel triple-loop mattress suture (twisted or nontwisted) is useful and comparable with existing suture techniques used in high-tension sites, with potential added use as a temporary holding suture to maximize tissue creep. Twisted loops appear to withstand higher tensile strength than nontwisted variants of the same technique and could be considered in appropriate cases.