Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
J Neurosurg. 2010 Jul;113(1):122-8. doi: 10.3171/2009.10.jns09698.
The authors conducted a study to determine age- and time-dependent effects on the functional outcome after median nerve injury and repair and how such effects are related to changes in the pattern of cortical activation in response to tactile stimulation of the injured hand.
The authors studied 11 patients with complete unilateral median nerve injury at the wrist repaired with epineural suture. In addition, 8 patients who were reported on in a previous study were included in the statistical analysis. In the entire study cohort, the mean age at injury was 23.3 +/- 13.4 years (range 7-57 years) and the time after injury ranged from 1 to 11 years. Sensory perception was measured with the static 2-point discrimination test and monofilaments. Functional MR imaging was conducted during tactile stimulation (brush strokes) of Digits II-III and IV-V of both hands, respectively.
Tactile sensation was diminished in the median territory in all patients. The strongest predictor of 2-point discrimination was age at injury (p < 0.0048), and when this was accounted for in the regression analysis, the other age- and time-dependent predictors had no effect. The activation ratios (injured/healthy hand) for Digit II-III and Digit IV-V stimulation were positively correlated (rho 0.59, p < 0.011). The activation ratio for Digit II-III stimulation correlated weakly with time after injury (p < 0.041). The activation ratio of Digits IV-V correlated weakly with both age at injury (p < 0.048) and time after injury (p < 0.033), but no predictor reached significance in the regression model. The mean ratio of ipsi- and contralateral hemisphere activation after stimulation of the injured hand was 0.55, which was not significantly different from the corresponding ratio of the healthy hand (0.66).
Following a median nerve injury (1-11 years after injury) there may be an initial increase in the volume of the cortical representation, which subsequently declines during the restoration phase. These dynamic changes may involve both median and ulnar nerve cortical representation, because both showed negative correlation with time after injury. These findings are in agreement with animal studies showing that cortical plasticity is an important mechanism for functional recovery after peripheral nerve injury and repair.
作者进行了一项研究，以确定正中神经损伤和修复后功能结果的年龄和时间依赖性，并探讨这些影响与受伤手触觉刺激时皮质激活模式变化的关系。
作者研究了 11 例正中神经腕部完全损伤的患者，均采用神经外膜缝合修复。此外，还纳入了先前研究中报告的 8 例患者进行统计分析。在整个研究队列中，损伤时的平均年龄为 23.3 ± 13.4 岁（范围 7-57 岁），损伤后时间范围为 1 至 11 年。感觉感知通过静态 2 点辨别测试和单丝进行测量。功能性磁共振成像在双手第二至第三指和第四至第五指分别进行触觉刺激（刷笔触）时进行。
所有患者的正中神经支配区域触觉均减弱。2 点辨别力的最强预测因素是损伤时的年龄（p < 0.0048），当将其纳入回归分析时，其他年龄和时间依赖性预测因素没有影响。第二至第三指和第四至第五指刺激的激活比（患病/健康手）呈正相关（rho 0.59，p < 0.011）。第二至第三指刺激的激活比与损伤后时间呈弱相关（p < 0.041）。第四至第五指的激活比与损伤时的年龄（p < 0.048）和损伤后时间（p < 0.033）均呈弱相关，但在回归模型中没有预测因素达到显著水平。刺激患病手后对侧和同侧半球的平均激活比为 0.55，与健康手的相应比值（0.66）无显著差异。
正中神经损伤后（损伤后 1-11 年），皮质代表区的体积可能会先增加，然后在恢复阶段下降。这些动态变化可能涉及正中神经和尺神经皮质代表区，因为两者均与损伤后时间呈负相关。这些发现与动物研究一致，表明皮质可塑性是周围神经损伤和修复后功能恢复的重要机制。
