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Fate of Costochondral Grafts for Micrognathia: 3D Analysis of Postoperative Length, Position, and Graft Take

Purpose: Costochondral grafting is performed in the reconstruction of severe micrognathia. In this study, we report our experience with graft take, as well as unique findings that have not been focused on in the past literature such as postoperative position and changes in the shape of the graft and thinning of the skull base in contact with the graft. Methods: Between 2002 and 2019, costochondral grafting was performed on 15 sides of 10 patients with micrognathia. Graft take and other detailed findings such as growth, position, and changes in the shape of the grafts and skull base in contact with the grafts were evaluated using computed tomography images. Results: Graft take was obtained in all cases, and subsequent distraction could be performed in 8 of 10 graft sites as planned. Six of 15 grafts were displaced anterior to the preoperative planned position. However, there were no cases with complications due to deviation such as trismus. Concave deformity of the skull base in contact with the graft was observed in 9 graft sites. The thinning and bending deformation were observed in 2 grafts. Conclusions: Costochondral grafting was considered a reasonable method for first-line treatment of severe micrognathia. Several unique findings that have not been focused on in the past literature were observed. These should be kept in mind when performing costochondral grafting. Several modifications to the present protocol are suggested to improve the quality of graft take.