变速牵引成骨对兔下牙槽神经的影响

目的　研究变速牵引兔下颌骨15mm对下牙槽神经的影响。方法　5只新西兰白兔单侧下颌骨截开。延迟5d ,以每天1 5mm ,每天2次牵引9mm ,然后继续以每天1mm ,每天2次牵引6mm ,完成牵引后固定15周,分别行肉眼及组织学观察和电生理学检查。结果　下颌骨延长15mm ,新骨生成良好。下牙槽神经牵长2 1. 99% ,牵引结束时神经变性明显,感觉神经动作电位波幅下降为术前的9. 70 % ,潜伏期较术前有所延长,随后出现恢复趋势,到固定15周时,波幅恢复到术前的33. 85 % ,潜伏期基本恢复正常。结论　下颌骨变速牵引15mm后,下牙槽神经受到明显的影响,到15周时,下牙槽神经的功能有恢复的趋势,但恢复尚不完全。

Influence of distraction osteogenesis on rabbit inferior alveolar nerve by varying rate

Objective To study the influence of mandibular distraction osteogenesis of 15mm on the rabbit inferior alveolar nerve(IAN) by varying the rate. Methods The osteotomy was performed in the unilateral mandibles of 5 New Zealand rabbits. After a 5-day latency period, the distraction progressed at a rate of 0.75 mm×2 /d for 9 mm, then at a rate of 0.5 mm×2 /d for the other 6 mm. This was followed by a 15-week consolidation phase. Histological and electrophysiological examinations were performed.Results The mandible was lengthened to 15 mm and new bone well formed. The IAN was average 21.99% longer than its original length. When the distraction was completed, serious nerve degeneration was observed. The amplitude of the sensory nerve action potential (SNAP) was only 9.70% of that before operation and the latency period showed certain prolongation. Then recovery trend was found. The amplitude was 33.85% of that before operation but the latency period almost completely recovered after 15 weeks.Conclusion After mandibular distraction osteogenesis of 15 mm by varying the rate, serious influence on the inferior alveolar nerve was found. The IAN' function showed recovery trend after 15 weeks, but this recovery trend was not complete.