Hirohashi T
Department of Orthopaedic Surgery, Kurume University School of Medicine, Japan.
Kurume Med J. 2000;47(1):73-8. doi: 10.2739/kurumemedj.47.73.
To study the effect of laser irradiation on normal lumbar discs, a 2100 nm Holmium (HO)-YAG laser irradiation was applied to the 83 lumbar discs of 23 adult rabbits. The extent of disc vaporization, the temperature changes in the surrounding tissues, and changes in the radiograph and MRI findings were assessed after laser irradiation. When laser irradiation was delivered to the discs, the disc weight decreased linearly with the increase in total laser energy, indicating steady vaporization of disc material. The temperature was highest at the site of the guide needle. Laser irradiation was delivered at 0.5 J/pulse or 1.4 J/pulse x 5 pulses/sec to the intervertebral discs, and radiographs and T2-weighted MRI of the irradiated discs were investigated at 1, 4, and at 12 weeks after irradiation. At 1 week after irradiation at 0.5 and 1.4 J/pulse, the radiographs showed a decrease in the disc height. At 12 weeks after irradiation at 0.5 J/pulse, the disc height had restored to normal, while the decrease was persistent after irradiation at 1.4 J/pulse. At 1 week after irradiation, MRI showed a decrease in the signal intensity of discs treated at 0.5 J/pulse, but the decrease was recovered at 12 weeks. After irradiation at 1.4 J/pulse, the decrease in signal intensity was also recovered by 12 weeks, but the recovery was less than the recovery after treatment at 0.5 J/pulse. Laser irradiation is applicable for the treatment of intervertebral discs, but it is necessary to select the optimal operating conditions. It may also be necessary to change the power of irradiation according to the pathological condition of the disc being treated.
为研究激光照射对正常腰椎间盘的影响，对23只成年兔的83个腰椎间盘进行了2100纳米钬（Ho）-钇铝石榴石激光照射。激光照射后评估椎间盘汽化程度、周围组织温度变化以及X线片和磁共振成像（MRI）表现的变化。当对椎间盘进行激光照射时，椎间盘重量随总激光能量增加呈线性下降，表明椎间盘物质稳定汽化。导针部位温度最高。以0.5焦耳/脉冲或1.4焦耳/脉冲×5脉冲/秒的能量对椎间盘进行激光照射，并在照射后1周、4周和12周对照射后的椎间盘进行X线片和T2加权MRI检查。在0.5焦耳/脉冲和1.4焦耳/脉冲照射后1周，X线片显示椎间盘高度降低。在0.5焦耳/脉冲照射后12周，椎间盘高度恢复正常，而在1.4焦耳/脉冲照射后高度持续降低。照射后1周，MRI显示0.5焦耳/脉冲处理的椎间盘信号强度降低，但在12周时恢复。在1.4焦耳/脉冲照射后，信号强度降低在12周时也有所恢复，但恢复程度低于0.5焦耳/脉冲处理后的恢复程度。激光照射适用于椎间盘治疗，但有必要选择最佳操作条件。根据所治疗椎间盘的病理状况改变照射功率可能也是必要的。
