Background Carpal tunnel syndrome (CTS) is the most common and well-described compression neuropathy of the upper limb. Scales like DN4 (Douleur Neuropathique 4) and LANSS (Leeds Assessment of Neuropathic Symptoms and Signs) are frequently used to determine pain mechanism (neuropathic and/or nociceptive). To the best of our knowledge, there is no existing study investigating neuropathic complaints and it's relation between electrophysiologic changes after single local steroid injection in CTS.
Objectives We tried to find out if there is a relationship between DN4/LANSS score changes and electrophysiologic changes after single local steroid injection.
Methods 41 participants diagnosed clinically and electrophysiologically with idiopathic CTS between the ages of 20-65 years were included in the study. LANSS and DN4 neuropathic pain scales were used to identify neuropathic pain and patients with neuropathic complaints (DN4 ≥4 and LANSS ≥12) were received local steroid injection into the carpal tunnel. Tests were repeated 2 months after the injection.
Results When compared to pre-treatment results a moderate correlation was observed between SNAP (Sensory Nerve Axon Potential) changes and DN4 scores (p<0.05, r: 0.340) in this study (Table 1). We think due to ineffectiveness of routine nerve conduction studies on evaluating thin nerve fibers, no further relationship was observed and relation between DN4 and SNAP may be related to sensitization of thick myelinated A-beta nerve fibers which physiologically supply fine touch, vibration and position sense and can be evaluated with routine nerve conduction studies.
Conclusions Additional studies are needed to explain the contribution of thick myelinated fiber dysfunction to pain mechanisms and these complex findings in CTS.
Disclosure of Interest None declared
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