[Specific strength measurement of musculus abductor pollicis brevis in order to objectively evaluate muscle regeneration after carpal tunnel release surgery].

47 patients with a carpal tunnel syndrome were preoperatively examined not only by electrophysical studies (nerve velocity and distal motoric latency) and clinical tests (Phalen's sign, Tinel's sign) but also by measuring the strength of the M. abductor pollicis brevis with a specifically designed strength-testing unit. 30 patients agreed to participate in a voluntary postoperative examination. In the 45 degrees -measurement there was a relative strength loss of the injured hand's thumb of about 25 % in comparison with the healthy hand preoperatively. The postoperative strength disadvantage amounted to only 10 %. Measurement of the strength in the neutral zero method showed a relative strength loss of the injured hand's thumb of 8 % while postoperatively there was even a strength advantage of 9 % in comparison with the thumb of the healthy hand. Both methods showed a relevant and significant postoperative strength increase of the injured hand's thumb. We could prove a significant correlation (p = 0.03) of the neutral zero strength measurement and the distal motoric latency of the median nerve. Furthermore, we could show a trend for a correlation between the neutral zero strength measurement and the median motoric velocity. In conclusion, it can be said that the special strength measurement of the M. abductor pollicis brevis is an important parameter to objectively evaluate the motoric symptomatology in carpal tunnel syndrome patients.