턱 끝 비대칭 환자의 수술방법 선택을 위한 알고리즘

Abstract

From an aesthetic viewpoint, the symmetry of the chin is very important in maintaining facial symmetry and aesthetics. Deviations in the chin are often corrected using simple genioplasty. In many cases, however, this procedure is not satisfactory because it fails to address other asymmetric factors in facial skeleton that contribute to chin asymmetry. Many operative procedures, such as genioplasty, partial mandibular ostectomy, and two-jaw surgery have been utilized, but few papers have focused on the initial evaluation for proper treatment plan. We have tried to establish simple guidelines for the selection of treatment in the deviated chin patient without malocclusion. In order to select the proper corrective procedure, we have focused the etiologies of chin deviation into the following four categories: mandible ramus asymmetry, maxillary height asymmetry, mandibular body & symphysis asymmetry, and asymmetry of mandible symphysis itself. Evaluations of chin deviation begin with measurements of the posterior mandibular height, maxillary height, and lower border of mandibular body using Panorex, PA and Lateral cephalometry films. These parameters are then utilized in our new algorithm to divide chin deviations into four groups. Depending on the category, a different operation would be indicated. When the major asymmetrical factor is in the posterior mandibular height(category 1), they are corrected using ramus distraction. When the major asymmetrical factor is in the maxilla height(Category 2), they are corrected using bimaxillary surgery with maxillary and mandibular rotation. Symmetrical mandibular and maxillary height with asymmetrical mandibular bodies & symphysis(Category 3) are corrected using genioplasty with body ostectomy. All other cases(Category 4) were corrected using only genioplasty. From July 1999 to June 2001, 15 patients with deviated chin and normal occlusion were diagnosed and corrected using this algorithm. Ramus distraction devices were applied in 4 cases. 3 cases required Le Fort I osteotomy in combination with sagittal split ramus osteotomy. Mandibular body ostectomy with genioplasty were used in 3 cases. The remaining 5 cases required only genioplasty. We obtained successful correction in all cases objectively and subjectively. We recommend using this algorithm as a helpful guide-line in the selection of treatment option for the patients who present with a deviated chin & normal occlusion.