Novel "Z" Technique to Overcome Warping of Costal Cartilage.

[BACKGROUND] Dorsal augmentation with costal cartilage is generally used for aesthetic rhinoplasty. However, the tendency of costal cartilage to warp may jeopardize the aesthetic outcome.

[OBJECTIVES] The aim of this study was to describe a new "Z" technique to overcome the warping of costal cartilage after implantation and to evaluate the efficacy of this technique in vitro.

[METHODS] A total of 31 pairs of porcine costal cartilage grafts (40 mm × 10 mm × 5 mm) were obtained and kept in Dulbecco's Modified Eagle Medium (Sigma-Aldrich, St. Louis, MO) to maintain cell viability. Paired grafts were obtained and randomly allocated for preparation by the accordion technique and the "Z" technique. Standardized photographs (obtained immediately after operation and at 4 weeks) were used for warping analysis. Biomechanical testing was performed to measure the graft's capacity to resist deformation by an external force.

[RESULTS] Cell viability of the grafts at 4 weeks was comparably good in the accordion group and the Z group (61.88% ± 4.47% vs 67.48% ± 7.03%, P = 0.55). Warping angle was comparable between the 2 groups (P > 0.01). The capacity to resist external force was significantly better in the Z group; the force needed to cause deformation was 3.98 ± 1.04 N in the Z group vs 1.61 ± 0.47 N in the accordion group in lateral view (P < 0.0001), and 1.33 ± 0.41 N vs 0.96 ± 0.24 N, respectively, in frontal view (P = 0.0013).

[CONCLUSIONS] The "Z" technique appears to be a simple and effective method to minimize the tendency of costal cartilage to warp after implantation.