变速牵引与常速牵引成骨对下牙槽神经影响的比较研究

Effects on the inferior alveolar nerve following distraction osteogenesis by varying the rate and at usual rate: a comparative study

目的:通过比较变换速度和常规速度牵引成骨对下牙槽神经的影响,探讨较大距离牵引时提高牵引成骨效率的可能途径。方法:新西兰白兔9只,随机分成2组,单侧下颌骨截开。延迟5 d。变速组5只,以0.75mm×2/d,牵引9 mm,继续以0.5 mm×2/d,牵引6 mm,最长固定30周。常速组4只,以0.5 mm×2/d,牵引15mm,最长固定15周。分别行大体观察、电生理检查和组织学观察。结果:下颌骨延长15 mm,两组新骨都生长良好。牵引后两组下牙槽神经出现严重变性,感觉神经动作电位波幅明显下降,潜伏期延长,固定15周时,两组波幅都出现恢复趋势,潜伏期基本恢复,固定30周时,变速组神经结构和功能基本恢复正常。结论:变速牵引成骨可以在不增加下牙槽神经损伤的情况下,提高牵引成骨的效率。

Objective： To discuss the possible methods to enhance the efficiency of distraction ostcogenesis with longer distraction length by comparatively studying the effects on the inferior alveolar nerve following distraction ostcogenesis by varying the rate and at usual rate. Method：9 New Zealand rabbits were randomized in 2 groups. The unilateral mandible osteotomy was performed and a latency period of 5 days was followed. In the group by varying the rate, the distractor was activated at a rate of 0.75 mm×2/d to 9 mm, then at a rate of 0.5 mm×2/d to the other 6 mm, and consolidated for 30 weeks at most. In the other group at usual rate, the distractor was activated at 0.5 mm × 2/d to 15 ram, and consolidated for 15 weeks at most. Electrophysiological and histological observations were performed. Result： Regenerated bone was well formed in both groups following mandibular lengthening to 15 mm. Serious nerve degeneration was found in both groups at the complication of distraction. The amplitude of sensory nerve action potential decreased and the lantency period prolonged obviously. At 15 weeks of the consolidation, recovery trend of the amplitude was found in the two groups and the lantency period almost completely recovered. At 30 weeks of the consolidation, the strucure and function of the inferior alveolar nerve in the group by varying the rate generally recovered to the normal level. Conclusion： Distraction ostcogenesis by varying the rate could enhance the efficiency of distraction osteogenesis with longer distraction length without increasing the inferior alveolar nerve injury.