Nerve Conduction Studies in Carpal Tunnel Syndrome: Application of Quantitative Methods of Decision Making.

Abstract

Carpal tunnel syndrome (CTS) is a common compressive neuropathy that is diagnosed primarily through clinical symptoms and electrodiagnostic testing. However, the lack of a gold standard and the varied accuracy of nerve conduction studies (NCS) present challenges in diagnosis and treatment decisions. This study aimed to evaluate the efficacy of different measurements of NCS in patients with CTS, analyze the postoperative changes in NCS, and identify factors associated with surgical outcomes. A total of 565 patients (1077 hands) presenting with CTS symptoms from 2003 to 2018 at Far East Memorial Hospital (Taiwan) were included. The NCS measurements, including motor nerve peak latency (MNPL), sensory nerve peak latency, compound muscle action potential amplitude, motor nerve conduction velocity, and sensory nerve conduction velocity, were recorded. A total of 630 hands underwent carpal ligament release surgery. Postoperative NCS was performed after 2 months, and the data underwent statistical analyses. The study found that MNPL was the most significant NCS measurement associated with the likelihood of receiving surgery (odds ratio: 1.30, P < 0.001). However, the logistic regression model for predicting surgery had limited predictive power (area under the curve: 0.7122). Postoperative NCS showed significant decreases in MNPL and compound muscle action potential amplitude and an increase in sensory nerve conduction velocity (P < 0.001). Factors associated with poorer postoperative outcomes (higher postop MNPL) included older age, higher preoperative MNPL, lower preoperative sensory nerve peak latency, and lower preoperative motor nerve conduction velocity. Although MNPL is the most significant NCS factor associated with CTS severity, NCS measurements alone are insufficient for precise surgical decision-making. Additional clinical factors should be considered for a more comprehensive evaluation of CTS and treatment decisions.