Wrist median nerve motor conduction after end range repeated flexion and extension passive movements in Carpal Tunnel Syndrome. Pilot study

Carpal Tunnel Syndrome (CTS) can be due to a variety of different pathological conditions. These etiological and epidemiological differences may explain the non-homogeneous response to ordinary conservative therapeutical options observed in this syndrome. The aim of our study was to investigate on the possibility of identifying different sub-groups of patients among conservatively treatable CTS with different susceptibility to physiotherapeutic treatments. We decided to utilize an objective approach measuring some median motor nerve function parameters. Short term variations of Compound Motor Action Potential (CMAP) from the thenar eminence were compared in two groups of 55 hands (CTS patients and normal controls) after performance of two different types of end range passive movement. We found a different distribution of CMAP amplitude modifications within a sub-group of patients that suddenly improved more than the controls after two series of 10 end range passive flexions or after two series of ten end range passive extensions. Amplitude changes proved to be much more useful than latency variation studies in the provocative test neurophysiological approach. The method we propose appears to be useful for better surgical indication and/or for improvement of conservative therapeutic choice.