Subramanian Senthil Kumar, Rajendran Rajathi
Department of Physiology, AIIMS, Madurai, Tamil Nadu, India.
Department of Physiology, AIIMS, Bathinda, Punjab, India.
Ann Neurosci. 2025 Jan 10:09727531241306863. doi: 10.1177/09727531241306863.
Carpal Tunnel Syndrome (CTS) is the most common entrapment neuropathy, characterised by compression of the median nerve at the wrist. Traditional understanding views CTS as a distal compression issue, but recent evidence suggests potential proximal involvement.
This study aimed to assess the prevalence of proximal median nerve conduction velocity (CV) slowing in CTS patients and examine its association with CTS severity.
In this retrospective observational study, data were analysed from 80 CTS patients and 40 controls from the Electrophysiology Lab at a tertiary care institute. Nerve conduction studies (NCS) evaluated the median nerve's conduction velocity and latency. Patients were classified by CTS severity, and nerve conduction parameters were statistically compared between groups.
CTS patients exhibited significantly prolonged distal motor latency (DML) (5.2 ± 0.8 ms) and reduced forearm motor conduction velocity (MCV) (55.3 ± 4.1 m/s) compared to controls ( < .01). Approximately 27.45% of CTS hands showed proximal median nerve slowing. The severity classification showed that Grade 3 CTS was the most prevalent (47%), followed by Grade 2 (23%) and Grade 1 (10%). There was a negative correlation between distal latency and forearm conduction velocity, suggesting that as distal latency increases, forearm conduction velocity decreases. Post-operatively, significant improvements were observed in distal latency (mean decrease: 1.2 ± 0.5 ms, < .01), but median nerve conduction velocity remained unchanged. While there was a trend towards improvement in CMAP amplitude, the difference did not reach statistical significance.
A subset of CTS cases exhibits reduced proximal median nerve conduction velocity, which correlates with CTS severity. This suggests retrograde degeneration may contribute to CTS pathology, challenging the traditional view of CTS as a purely distal compression disorder.
腕管综合征（CTS）是最常见的卡压性神经病，其特征是正中神经在腕部受到压迫。传统观点认为CTS是一种远端压迫问题，但最近的证据表明可能存在近端受累情况。
本研究旨在评估CTS患者近端正中神经传导速度（CV）减慢的发生率，并探讨其与CTS严重程度的关系。
在这项回顾性观察研究中，分析了一家三级医疗机构电生理实验室的80例CTS患者和40例对照的数据。神经传导研究（NCS）评估了正中神经的传导速度和潜伏期。根据CTS严重程度对患者进行分类，并对各组之间的神经传导参数进行统计学比较。
与对照组相比，CTS患者的远端运动潜伏期（DML）显著延长（5.2±0.8毫秒），前臂运动传导速度（MCV）降低（55.3±4.1米/秒）（P<0.01）。约27.45%的CTS患手显示近端正中神经减慢。严重程度分类显示，3级CTS最为常见（47%），其次是2级（23%）和1级（10%）。远端潜伏期与前臂传导速度之间存在负相关，表明随着远端潜伏期增加，前臂传导速度降低。术后，远端潜伏期有显著改善（平均降低：1.2±0.5毫秒，P<0.01），但正中神经传导速度保持不变。虽然复合肌肉动作电位（CMAP）波幅有改善趋势，但差异未达到统计学意义。
一部分CTS病例表现出近端正中神经传导速度降低，这与CTS严重程度相关。这表明逆行性变性可能导致CTS病理改变，挑战了CTS是纯粹远端压迫性疾病的传统观点。
