发育期羊全颞下颌关节置换术后的下颌骨对称性评价

Mandibular symmetry evaluation of total temporomandibular joint replacement on developmental stage sheep

目的:利用Surgicase5.0软件对发育期羊全颞下颌关节(temporomandibular joint,TMJ)置换进行手术设计,研究其重建后的下颌骨对称性。方法:选择6个月龄山羊6只,术前行CT检查,收集数据(Dicom格式),通过Surgicase5.0软件重建三维数字模型,结合快速成型技术获得羊三维头颅树脂模型,在模型上设计、制备个性化人工全TMJ假体,并模拟手术,进行全TMJ置换;右侧进行手术,作为实验组,左侧为对照组。术后1、4、12周行CT扫描,在三维模型上测量两侧下颌支高度(ramus heights,RH)、下颌体长度(mandibular body length,ML)、髁突顶点到下颌中切牙近中接触点距离(condyle-incisor,CI)、下牙槽座角到髁突顶点距离(subramental-condyle,BC),采用SPSS16.0软件包对所测数据进行左右侧配对t检验,左右侧各时间点分别与术前进行配对t检验。结果:所有动物均存活至实验完成,能正常进食。术后1、4周左右侧RH、ML、CI、BC均无显著差异(P>0.05);术后12周,除ML外,左右侧RH、CI、BC差异有显著性(P<0.05)。右侧术后1周RH、ML、CI、BC,4周RH、BC,12周RH与术前比较均无显著差异(P>0.05)。左侧术后1周RH、ML、CI、BC,4周RH与术前比较无显著差异(P>0.05)。结论:个性化设计的羊全TMJ假体能较好地行使关节功能。对发育期羊进行全TMJ假体置换,术后远期可能致面形不对称。

PURPOSE： To evaluate the mandibular symmetry after temporomandibular joint （TMJ） replacement by SurgicaseS.0 software in developmental stage sheep. METHODS： Six developmental stage sheep were included in our study. Spiral computed tomography （CT） data of all six sheep was obtained and transformed into 3-dimensional model by SurgicaseS.0 software preoperatively. 3-dimensional resin skull models of sheep were obtained by rapid prototyping technique, based on which total TMJ prostheses were made and surgical planning and simulation were achieved by SurgicaseS.0 software. The right sides, which were as the experimental group, of all six sheep underwent operation based on preoperative planning, while the left sides as control group. CT scanning was performed one week, four and twelve weeks after operation. Ramus heights （RH）, mandibular body length （ML）, condyle-incisor （CI） and subramental-condyle （BC） of both experimental and control group were measured and compared by paired t test. Meanwhile those measurements before and after operation on experimental or control group were compared by paired t test using SPSS16.0 software package. RESULTS： All animals were alive to the end of experiment with good recovery of masticatory function and normal eating. There was no significant difference between the experimental and control groups for any parameter of RH, ML, CI, BC after one week or four weeks. There were significant difference for RH, CI, BC except ML after twelve weeks. The comparison before and after operation on experimental group showed that there were no significant difference on RH,ML, CI, BC after one week, RH, BC after four weeks and RH after twelve weeks. Comparison before and after operation on the control group showed that there was no significant difference on RH, ML, CI, BC after one week and RH after four weeks. CONCLUSIONS： The function of natural TMJ of sheep can be well reconstructed by personally designed total TMJ prosthesis. Total TMJ replacement in developmental stage sheep may result in mandibular asymmetry. Supported by Shanghai Leading Academic Discipline Project （S30206）, Shanghai Pujiang Talent Plan in 2011 and Natural Science Foundation of Shanghai Municipality （ 10ZR 14 18200）.