头颈部放射治疗对咀嚼肌神经电生理的影响

Effect of radiation therapy of head and neck on electroneurophysiology of masticatory muscles

目的:探讨放疗后开口受限的发病机制,为临床放射治疗后开口受限的预防和治疗提供一定的实验依据。方法:以接受头颈部放射治疗后的7例患者为研究对象。分别对患者健、患侧咬肌、翼内肌与翼外肌进行同心圆针肌电图(EMG)检查,同时测量患者开口度。对受照射侧与未受照射侧咀嚼肌静息状态下出现失神经电位情况进行统计分析。结果:放射区域涉及咬肌有4例患者:肌肉静息状态下2例患者患侧咬肌出现失神经电位;肌肉大力收缩状态下2例患者患侧咬肌无募集电位;该4例患者开口度分别为16mm、31mm、15mm和9mm。放射区域涉及咬肌、翼内肌与翼外肌的有3例患者:肌肉静息状态下1例患者患侧翼外肌、咬肌出现失神经电位,1例患者患侧咬肌、翼内肌与翼外肌均出现失神经电位;肌肉大力收缩状态下,1例患者患侧咬肌、翼内肌与翼外肌均无募集电位。该3例患者开口度为39mm、17mm、5mm。受照射侧与未受照射侧出现失神经电位咀嚼肌数差异有统计学意义(P<0.01)。结论:头颈部放射治疗可引起放射区域咀嚼肌神经电生理异常改变,造成放射性周围神经病理性损伤;咀嚼肌神经肌肉系统的放射损伤是放射治疗后开口受限的发生因素之一。

Objective： To explore the mechanism of restriction of mouth opening caused by radiation therapy. Methods：7 patients treated with head and neck radiotherapy were recruited. Maximum mouth opening was measured. Masseter, lateral pterygoid muscle and medial pterygoid muscle of the patients were tested with electromyography（EMG）. The difference of numbers of masticatory muscles with denervation potentials between healthy and experimental side were analyzed by Fisher＇s exact test for 2×2 contingency table. Results： Four patients＇ masseter were irradiated by X-ray： On muscle resting state, denervation potentials were present in two patients; On muscle maximal contraction, the recruitment potentials had not been found in two patients. The maximum mouth opening of the four patients are 16 mm, 31 mm, 15 mm and 9mm.Three patients＇ masseter and pterygoid muscles were all irradiated by X-ray： On muscle resting state, denervation potentials were present in one patient＇s masseter and lateral pterygoid muscles and another one patient＇s all three masticatory muscles; On muscle maximal contraction, One patient＇s recruitment potentials of lateral pterygoid muscle showed simple phase, one patient＇s recruitment potentials of all three masticatory muscles had not been found. The three patients＇ maximum mouth opening are 39 mm, 17 mm, and 5mm. The differences of numbers of masticatory muscles with denervation potentials was significant between healthy and experimental side（P〈 0.01）. Conclusion： The radiation therapy of head and neck is detrimental to the neuromuscular system of masseter and pterygoid muscles. The injury of the neuromuscular system of masticatory muscles may be one of the factors causing trismus.