近赤外酸素代謝モニターを用いた腰背筋の評価

Assessment of Human Lumbar Muscle Using Near-Infrared Spectroscopy

　抄録：腰痛自覚者における活動筋での酸素利用の時系列的な情報を得ることを目的として，近赤外酸素代謝モニターを用いて腰背筋におけるヘモグロビンの酸素化-脱酸素化状態の変化を測定した．対象は計50例の慢性腰痛あり，なし両群で，腰椎伸展中における酸素化ヘモグロビン（Oxy-Hb），脱酸素化ヘモグロビン（Doxy-Hb），総ヘモグロビン（Total-Hb），酸素化率（SdO₂）の経時的変化を記録した．Oxy-Hbの相対変化量は有意に腰痛あり群で少なく，またOxy-Hb上昇のピークまでに要する時間は腰痛あり群で有意に長かった．Doxy-Hb変化量，SdO₂変化量ともに両群間で有意差を認めなかった．腰痛自覚者において腰椎伸展中のOxy-Hbの上昇とそのピークまでの到達時間が緩徐であったことは，高強度の運動時にO₂extractionの増加に対応する筋パフォーマンスが低下していることが予測された．

　Purpose：To evaluate tissue oxygenation during exercise in lumbar muscle using near-infrared spectroscopy (NIRS).

　Methods：The subject analyzed totaled 50 patients (mean age of 68.5) comprising two groups of equal numbers；The LBP group who complained of chronic low back pain and the non-LBP group who had no complaints. A NIRS (OM-220, Shimadzu Co., Japan) were positioned while extending the lumbar spine for 15 seconds. Measurements of the relative changes in oxygenated hemoglobin (Oxy-Hb) were obtained.

　Results：The amount of relative change in Oxy-Hb was significantly less in the LBP group than in the non-LBP group. The interval until the peak of the Oxy-Hb curve was significantly longer in the LBP group than in the non-LBP group.

　Conclusions：The results indicate that muscle performance corresponding to increased O₂extraction during high intensity exercise may be decreased in patients with low back pain. NIRS provides valuable information regarding O₂transport and extraction in the exercising lumbar muscle, and has the potential to be useful for study of low back pain.