A biomechanical comparison of vertical figure-of-eight locking suture for septal extension grafts

Septal extension grafts are performed in order to correct the conformation of the nasal tip and columella. The more strongly the graft is fixed to the columellar L-strut of the septal cartilage, the better is the outcome of grafting. This article reports the development of a vertical figure-of-eight locking suture technique and its biomechanical comparison with other suture techniques. Pieces of porcine rib cartilage 20 x 15 x 1 mm (or 2 mm) in size were used for the study. Two pieces of cartilage were fixed using two simple interrupted sutures in the first group, two horizontal figure-of-eight locking sutures in the second group and the vertical figure-of-eight locking suture in the third group. Shearing, buckling and tensile forces were measured with respect to the direction of forces that occur in vivo. The mean shearing force for cartilages that were 1 mm in thickness was 0.70, 0.74 and 1.04 N (P=0.056) in the first, second and third group, respectively. The mean buckling force was 1.10, 1.09 and 1.39 N (P=0.030), and the mean tensile force was 1.86, 1.78 and 2.24 (P=0.042), respectively. For cartilages that were 2 mm in thickness, the mean shearing force was 1.19, 1.29 and 1.54 N (P=0.216), the mean buckling force was 1.74, 1.50 and 2.25 (P=0.002) and the mean tensile force was 2.00, 1.81 and 2.29 (P=0.023) in the first, second and third group, respectively. The vertical figure-of-eight locking suture technique was developed as an alternative technique for suturing a septal extension graft to the columellar L-strut, and it enables firm fixation with the use of the fewest number of stitches.