Reconstruction of the mandlbular condyle using transport distraction osteogenesis.

本文报道了应用运输牵引成骨技术重建兔颞下颌关节的实验研究。1.X线分析选用白色家兔42只，体重3.0公斤左右。切除15mm的升支和颞下颌关节，包括其盘。然后，进行aL截骨术，从冠状突前缘延伸到下颌骨后缘。然后应用内部牵引装置。转移盘每天推进0.9mm（每天两次，每次0.45mm），持续14天。实验持续到术后24周，在延长完成后，每隔一段时间处死兔。X线分析显示，牵引后8周，牵引间隙与相邻的先前存在的下颌骨变得难以区分。在运输盘的前缘也观察到新骨。这个新骨经历了重塑，变得类似于原来的髁头。2.组织学观察牵张后2周和4周，牵张间隙两侧可见纵向新生骨小梁桥接。同时观察到大量软骨在差距的整个宽度上扩散。这表明在牵张间隙内建立的新骨是通过膜内骨化和软骨内骨化形成的。在运输盘的前缘也观察到新骨。这块骨头似乎是从周围的骨膜上再生出来的。牵张完成后8周以上，成熟皮质骨结构重建。在转移牵张过程中，在前缘观察到胶原帽的形成，其似乎替代了关节盘。

We report that the temporomandibular joint (TMJ) is to be reconstructed using the technique of transport distraction osteogenesis in rabbit experimental studies. We also report the analysis of the arthroplasty of TMJ using this technique.1.X-ray analysisA total of 42 white rabbits, each weighing about 3.0 Kg were used. A 15mm ascending ramus and TMJ including its disc was extirpated Next, aL-osteotomy was performed, extending from the anterior border of the coronoid process to the posterior border of the mandible. An internal distraction appliance was then applied. The transport disc was advanced 0.9mm per day (0.45mm twice daily) for 14days. The experiment lasted for 24 postoperative weeks after completion of the lengthening and the rabbits were sacrificed at intervals. X-ray analysis showed that the distracted gap became indistinguishable from the adjacent preexisting mandible at 8 weeks after distraction. The new bone was also observed at the leading edge of the transport disc. This new bone underwent remodelling and became similar to the original condylar head. The authors concluded that the bone transport technique is promising for the reconstruction of TMJ.2.Histological analysisAt 2 and 4 weeks after completion of distraction, longitudinal new bone trabeculae were seen to bridge the distraction gap on both sides. A large amount of cartilage was observed to spread over the full width of the gap simultaneously. This suggests that new bone established within the distraction gap is formed by both intramembranous and endochondral ossification. The new bone was also observed at the leading edge of the transport disc. This bone seemed to regenerate from the surrounding periosteum. After more than 8 weeks after completion of distraction, the structure of mature cortical bone was reconstructed. The formation of a collagenous cap during transport distraction was observed at the leading edge, which seemed to substitute for an articular disc.