顔面神経損傷後の回復過程に及ぼす低出力Ｎｄ‐ＹＡＧレーザーの影響

Abstract

This experiment was intended to confirm the effect of the low power Nd-YAG laser in promoting the regeneration of peripheral nerves objectively. From immediately after sectioning and suturing the bilateral facial nerves in a rabbit, the dermal surface in the right experimental region was irradiated by the laser (power density: 713mW/cm2, irradiation time: 30 min.) once daily and 5 times weekly up to the 4 th week.The temperature of the dermal surface during the irradiation time was maintained at 40°C. A comparative experiment was made by irradiating infrared rays under the same conditions. No irradiation was made to the left side as control. Observation of the recovering course was made in the 4th, Sth, 8th, 10th and 12th weeks after the treatment. A comparative assessment was made both electrophysiologically and histologically, and the following results have been obtained.1. Signs of recovery emerged earlier in the laser irradiaton group than the infrared irradiation group and control group electrophysioligically. The latency of action potential in the 8th week after the treatment was significantly short (p<0.05), and the threshold value in the strength-duration curve in the 6th, 8th and 10th weeks after the treatment was also significantly low (p<0.05).2. In die histogram of the nerve fiber area, the peak value of the distribution was shown to be high in the laser irradiation group, compared with those in the infrared irradiation group and control group in the 6th and 8th weeks after the treatment.From the above, it was clarified that the low power Nd-YAG laser promotes the regeneration of peripheral nerves, and it was considered that the thermal factor alone does not promote the regeneration.