下颌骨牵引成骨术对下牙槽神经功能影响的实验研究

目的　研究下颌骨牵引成骨术对下牙槽神经功能的影响。方法　对青年恒河猴 16只 ,全麻下行下颌角部骨截开术及牵引器置入术 ,术后第 5天开始以 0 5mm× 2次 /d的速度牵引 ,共15d。采用八导肌电图仪 ,表面电极在颏孔处刺激 ,针电极在卵圆孔附近记录 ,分别在术前、牵引完成后 0、2、4、6、9、12周时行感觉神经动作电位测试。结果　牵引完成时潜伏期较术前增加 2 2 18% ,其后逐渐降低 ,至牵引完成后 12周时仍较术前高 10 70 %。牵引完成时波幅降至术前的 2 8 5 4% ,牵引后 12周时恢复至术前的 99 84%。结论　下颌骨牵引成骨术对下牙槽神经的功能会产生暂时性影响 ,随着神经髓鞘和轴突的再生 ,神经功能可逐渐恢复正常。

Experimental study of the influence of mandibular distraction osteogenesis on inferior alveolar nerve function

OBJECTIVE: To evaluate the influence of mandibular distraction osteogenesis on inferior alveolar nerve function. METHODS: 16 young Macaca rhesus monkeys were used as experiment animals. 5 days after mandibular osteotomy under general anesthesia, 10 male monkeys were distracted at right side and 6 females were bilaterally distracted at a rate of 0.5 mm x 2/day, for 15 days. The mandible was lengthened to an average of 13.5 mm. The Sensory Nerve Action Potential (SNAP) test was successfully applied in 16 monkeys before operation and at 0, 2, 4, 6, 9 and 12 weeks after distraction finished. Eight-channel EMG equipment was used for SNAP wave recording. The recordings were made with needle electrodes at foramen ovale and the stimulation was done at the mental foramen with two surface electrodes. The metal ground electrode was fixed on the right forearm. The stimulation intensities were five times of thresholds of each animal. The latency was measured at the first wave peak and the amplitude was measured between two wave peaks. RESULTS: Just after distraction finished, the latency period was 22.18% longer than before operation and gradually shortened as time lapsed. When distraction finished, the amplitude of SNAP wave was only 28.54% of that before operation, and after 12 weeks, it increased to the level of 99.84% of that before operation. CONCLUSIONS: The mandibular distraction osteogenesis has temporary influence on the function of inferior alveolar nerve, but it is little and reversible, along with the regeneration of nerve sheath and axon, the nerve function can gradually return to normal level.