Value of the lumbrical-interosseous technique in carpal tunnel syndrome

Objective: To determine whether the second lumbrical-interosseous technique has comparable sensitivity with the median-ulnar transcarpal mixed nerve technique (palmdiff). Design: A prospective series of consecutive patients with median distribution paresthesias were evaluated with electrodiagnostic testing. Outpatient veterans referred by a heterogeneous group of specialists and generalists to the Portland Veterans Affairs Medical Center electrodiagnostic laboratory. A total of 129 consecutive veterans referred for evaluation of median distribution paresthesias were assessed with two electrodiagnostic tests. Results: The second lumbrical-interosseous technique performed with equal sensitivity (60.5%) to the palmdiff technique, with the added unique feature of its being uniformly obtainable. Conclusions: The second lumbrical-interosseous technique is characterized by performance equal to the palmdiff in categorizing carpal tunnel syndrome. It is also characterized by being nearly uniformly obtainable, even in severe carpal tunnel syndrome. These features suggest a wider role for the second lumbrical-interosseous technique than currently accepted.