腰椎椎間板ヘルニアにおけるcurrent perception threshold

The Current Perception Threshold in Lumbar Disc Herniation

　抄録：腰椎椎間板ヘルニア症例における下肢の知覚障害を，Neurometer^®を用いて定量的に分析した．MRI上L4/5またはL5/S1椎間板ヘルニアを認め坐骨神経痛を有する腰椎椎間板ヘルニア患者55名と，対照健常者11名を調査対象とした．両群とも両側下肢のL5およびS1領域の皮膚でCPT値の測定を行った．椎間板ヘルニア患者の患側では健側および対照群に比べ，2,000Hzおよび250Hz刺激に対するCPT値が有意に高値を示した．この結果より椎間板ヘルニアによる神経根障害では，Aβ線維とAδ線維が優位に障害されることが示唆された．MRI上の神経根圧迫の程度とCPT値の関係を調べると，神経根の圧迫が強い症例では圧迫が弱い症例に比べ，高いCPT値を示す傾向にあった．CPT値の測定により，椎間板ヘルニアによる神経根への圧迫の程度や神経線維の障害の程度を予測できる可能性が示唆された．

　Sensory disturbances in the legs of patients with lumbar disc herniation were quantitatively analyzed with a Neurometer^®. Fifty-five patients with radiculopathy secondary to lumbar disc herniation of the L4/5 or L5/S1 disc were examined, and 11 healthy volunteers served as controls. The L5 dermatome and the S1 dermatome of both legs were tested in all patients and controls. CPT values at 2,000Hz and 250Hz were significantly higher in the affected leg in the patient group than in the contralateral leg and in the controls. These results indicated predominant impairment of the function of A-beta and A-delta sensory fibers in patients with radiculopathy caused by lumbar disc herniation. CPT values in the affected leg were higher when the nerve root compression on the MR images was severer, but there were no significant differences between CPT values at any frequency. The results of this study suggested that CPT testing may be useful for predicting the severity of the nerve root compression and sensory nerve dysfunction in patients with lumbar radiculopathy.