Department of Oral and Maxillofacial Surgery, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea.
J Craniomaxillofac Surg. 2011 Dec;39(8):578-82. doi: 10.1016/j.jcms.2010.12.003. Epub 2011 Feb 5.
This study was carried out to evaluate the vertical and horizontal changes after maxillary surgery using resorbable plates made of an l-lactic acid and d-lactic acid copolymer of PLA (P(L/DL)LA), and to analyze factors of skeletal pattern and surgical movement affecting the post-surgical change.
The subjects consisted of 20 patients who underwent bimaxillary surgery using P(L/DL)LA resorbable plate (Inion CPS, Inion Ltd., Tampere, Finland). Lateral cephalograms were taken at 1 month before (T0), 1 month after (T1) and 6 months after surgery (T2). They were divided into two groups, one showing less relapse (LR) and one more relapse (MR) using K-means clustering analysis of post-surgical relapse (T2-T1). In terms of linear and angular variables of maxillary relapse, the two groups were compared with measurements at the pre-surgical stage (T0), the surgical change obtained (T1-T0) and post-surgical relapse (T2-T1) using Mann-Whitney test.
Because Frankfort horizontal (FH) to anterior nasal spine (ANS) showed the largest variance in post-surgical relapse of the maxilla, it was used for clustering analysis to define the MR and LR groups. Comparison between the MR and LR groups showed that a short preoperative anterior facial height (AFH) was a significant factor in maxillary relapse. The AFH of the MR group was significantly shorter pre-surgically (p<0.01) and was significantly increased postoperatively (p<0.05) when compared to the LR group. In post-surgical relapse, AFH, FH to A, FH to ANS and the palatal plane angle of the MR group were significantly decreased.
In the case of a short AFH, P(L/DL)LA resorbable plates may not provide enough vertical stability in the maxillary position due to the muscle force. Facial height might be an important factor when deciding to use P(L/DL)LA resorbable plates for maxillary surgery.
本研究旨在评估使用聚乳酸（PLA）的 L-乳酸和 D-乳酸共聚物（P（L/DL）LA）可吸收板进行上颌手术后的垂直和水平变化，并分析影响术后变化的骨骼形态和手术运动的因素。
本研究共纳入 20 例接受 P（L/DL）LA 可吸收板（Inion CPS，Inion Ltd.，坦佩雷，芬兰）双颌手术的患者。在手术前 1 个月（T0）、手术后 1 个月（T1）和 6 个月（T2）拍摄侧位头颅侧位片。采用术后复发（T2-T1）的 K-均值聚类分析，将患者分为复发较少（LR）和复发较多（MR）两组。使用 Mann-Whitney 检验，比较两组上颌骨复发的线性和角度变量与术前阶段（T0）、手术获得的变化（T1-T0）和术后复发（T2-T1）的测量值。
由于法兰克福平面（FH）到前鼻棘（ANS）在上颌术后复发中表现出最大的变异性，因此使用聚类分析来定义 MR 和 LR 组。MR 和 LR 组之间的比较表明，术前前面部高度（AFH）较短是上颌骨复发的一个显著因素。MR 组的术前 AFH 明显较短（p<0.01），与 LR 组相比，术后明显增加（p<0.05）。在术后复发方面，MR 组的 AFH、FH 到 A、FH 到 ANS 和腭平面角度均显著降低。
在 AFH 较短的情况下，由于肌肉力量，P（L/DL）LA 可吸收板可能无法在上颌位置提供足够的垂直稳定性。在决定是否使用 P（L/DL）LA 可吸收板进行上颌手术时，面部高度可能是一个重要因素。
