术中神经干动作电位波幅和波幅比值早期定量诊断周围神经损伤的对比实验研究

Comparison of nerve action potential amplitude and nerve proximal-to-distal amplitude ratio for assessment of severity of the nerve injury

目的 对比研究术中神经动作电位（nerve action potential,NAP）波幅值和近端正常神经与损伤段周围神经波幅比值（normal segment to injury segment amplitude ratio,NIAR）两种指标,用于早期定量评估周围神经损伤程度.方法 用16只新西兰兔建立坐骨神经损伤模型,伤后4周进行术中神经干动作电位检测,根据测定的NAP波幅值和NIAR分组.即根据NIAR波幅值分为：A组（NAP〈100μV,重度）,B组（100μV≤NAP〈500μV,中度）,C组（NAP≥500μV,轻度）;根据NIAR分组为：α组（比值≥10,重度）,β组（10〈比值≥2,中度）,γ组（比值〈2,轻度）.伤后12周在神经损伤点远端1cm处切取神经标本长2mm,经甘氨酸银染色后,观察各组切片中坐骨神经再生的轴索数量,测量其直径和横截面积,并进行足印测量和溃疡面积对比.得出的参数,进行组问t检验,P〈0.05判定为差异有显著性.结果 A组与B,C组的再生轴索数目、直径、横截面积、溃疡面积与足印宽长比参数有显著差异（P〈0.05）;α组与β,γ组参数差异有显著性（P〈0.05）;A组与α组,B组与β组,C组与γ组的各项参数差异均无显著性（P≥0.05）.结论 术中NAP波幅值和NIAK均可用于早期定量评估周围神经损伤程度.

Objective To compare nerve action potential （NAP） amplitude and Normal segment to injury segment amplitude ratio （NIAR） for early assessment of severity of the peripheral nerve injury. Methods Sixteen New Zealand rabbit were used as animal models for experimental surgery. During surgery, one of the sciatic nerves of the rabbit was intentionally damaged. At 4 weeks after surgery, the nerve was dissected for NAP detection. NAP amplitude of the nerve and amplitude of both proximal and distal to the injury site were recorded. The rabbits were then divided into 3 groups according to the values of NAP amplitude and NIAR, respectively. That is, group A （NAP amplitude 〈100μV, severe nerve injury）, B （100μV≤NAP amplitude 〈500μV, moderate nerve injury）, and C （NAP amplitude ≥500μV, mild nerve injury）; group α （NIAR ≥10, severe nerve injury）, group β （10〈 NIAR ≥2, moderate nerve injury）, and group y （NIAR 〈2, mild nerve injury）. At 12 weeks after primary surgery, a nerve segment 2 mm in length was obtained from the sciatic nerve at 1 cm distal to the injury site. The cross section of the nerve segment was stained by using Palmgren＇s silver stain. The number, diameter, and cross-section area of the regenerative axons were recorded. The footprint and area of the ulcer were also measured. These parameters of the groups were assessed by Student＇s t test （P〈0.05）was considered statistically significant. Results There were significant difference （P〈0.05） between group A and B, and group A and C in the assessment of the parameters. There were significant difference （P〈0.05） between group α and β, and group α and γ We found no significant difference （P≥0.05） between group A and α, B and β, and C and γ Conclusion Both NAP amplitude and NIAR can be used for early assessment of severity of the peripheral nerve injury.