Harris M D, Van Sickels J E, Alder M
Department of Oral and Maxillofacial Surgery, University of Texas, Health Sciences Center, San Antonio 78284-7908, USA.
J Oral Maxillofac Surg. 1999 Jun;57(6):650-4; discussion 654-5. doi: 10.1016/s0278-2391(99)90422-6.
Multiple articles have discussed condylar position after bilateral sagittal split osteotomy (BSSO). However, previous studies have been limited to two-dimensional evaluation of condylar position. The purpose of this study was to evaluate change in condylar position after a BSSO fixed with bicortical screws using three-dimensional computed tomography to assess the factors that may influence the ultimate position of the condyle after surgery.
Seventeen patients underwent isolated mandibular advancement involving a BSSO with rigid fixation. Reformated axial computed tomography was done 1 week before and 8 weeks after surgery. Movements evaluated included 1) medial-lateral, 2) superior-inferior, 3) anterior-posterior, and 4) condylar angulation. Three separate factors were analyzed to study their effects on the four movements noted: 1) amount of mandibular advancement, 2) amount of proximal segment rotation, and 3) preoperative shape of the mandible. A linear regression analysis was used with statistical significance set at P<.05.
Eight weeks after a BSSO and mandibular advancement, most cases showed displacement of the condyle medially, posteriorly, superiorly, and angled medially. The amount of mandibular advancement did not correlate with medial-lateral change of the condyle. The amount of advancement correlated with the condyle angulation and superior-inferior changes in condyle position. There was no correlation between amount of advancement and medial or anterior-posterior change in condyle position. There also was no correlation between any of the condylar movements and the degree of proximal segment rotation or the shape of the mandible.
There are obvious changes in condyle position after a BSSO. These changes appear to be influenced mainly by factors other than amount of advancement, degree of proximal segment rotation, and shape of the mandible.
多篇文章讨论了双侧矢状劈开截骨术（BSSO）后髁突的位置。然而，以往的研究仅限于对髁突位置的二维评估。本研究的目的是使用三维计算机断层扫描评估采用双皮质螺钉固定的BSSO术后髁突位置的变化，以评估可能影响术后髁突最终位置的因素。
17例患者接受了单纯下颌前徙术，包括采用坚固内固定的BSSO。在术前1周和术后8周进行轴向计算机断层扫描重建。评估的运动包括：1）内外侧；2）上下方向；3）前后方向；4）髁突角度。分析了三个独立因素对上述四种运动的影响：1）下颌前徙量；2）近心骨段旋转量；3）术前下颌骨形态。采用线性回归分析，设定统计学显著性水平为P<0.05。
在BSSO和下颌前徙术后8周，大多数病例显示髁突向内、后、上移位且向内成角。下颌前徙量与髁突的内外侧变化无关。前徙量与髁突角度及髁突位置的上下方向变化相关。前徙量与髁突位置的内侧或前后方向变化无关。髁突的任何运动与近心骨段旋转程度或下颌骨形态之间也无相关性。
BSSO术后髁突位置有明显变化。这些变化似乎主要受前徙量、近心骨段旋转程度和下颌骨形态以外的因素影响。
