Septal Extension Grafts in Rabbit Models: A Comparative Study Between Costal and Conchal Cartilage Grafts.

[BACKGROUND] The septal extension graft (SEG) has become the preferred augmentation rhinoplasty technique for Asian people due to its superiority in correcting tip projection and rotation.

[OBJECTIVES] The aim of this study was to build a rabbit model for SEG surgery and to compare the postoperative stability of nasal tip support provided by bilateral batten costal and conchal cartilage extension grafts.

[METHODS] Twenty rabbits underwent SEG surgery with either bilateral batten costal cartilage graft (Group A) or bilateral batten conchal cartilage graft (Group B). Serial photographs were obtained to evaluate the change of the nasal tip shape and graft shape. The observed indices include tip projection, tip angle, shape of extension graft, and histologic features of the extension graft.

[RESULTS] Twelve weeks after the operation, 1 costal extension graft in Group A (1/10) and 3 conchal extension grafts in Group B (3/10) were reabsorbed. The costal cartilage graft showed better exterior results than conchal cartilage graft in terms of tip projection and angle relapse rate (13.01% vs 25.02% and 15.18% vs 28.73%; P < .05). The costal cartilage graft maintained its structure better than the conchal cartilage graft. A greater degree of calcification and more fibrous capsules around the extension graft were found in Group A.

[CONCLUSIONS] A rhinoplasty rabbit model was established to compare costal and conchal autologous cartilages for SEG. This model may serve as a training tool for rhinoplasty surgeons. The costal cartilage extension graft is more reliable in terms of stability and should be given more attention.