More than half of patients regain thumb opposition after carpal tunnel release

CHICAGO — Although researchers from Japan found that overall 52.3% of patients who underwent release for carpal tunnel syndrome recovered thumb opposition, this recovery was unpredictable in patients older than 50 years.

Perspective from Kevin C. Chung, MD

“More than 90% of hands recovered in patients younger than 50 years of age,” Tatsuki Ebata, MD, of Chiba University, who presented the study, said. “On the other hand, only about half of hands recovered in the patients 50 years of age and older. Recovery of thumb opposition still remains unpredictable in these patients and further study, such as second lumbrical compound muscle action potentials, may be required to better predict the recovery of thumb opposition in severe carpal tunnel syndrome.”

Tatsuki Ebata

Of the 52.3% of hands that recovered thumb opposition, Ebata noted that all showed detectable APB-CMAPs. However, he said that 27 of the hands that did not recover thumb opposition had detectable APB-CMAPs and 25 had undetectable APB-CMAPs.

A mean amplitude of 3.72 mV was found in the hands that recovered thumb opposition vs. 1.1 mV in the hands that did not recover this motion. Distal motor latency was shorter in hands that recovered thumb opposition, but investigators found no significant difference regarding the disease duration between hands that recovered this ability (26.9 months) and hands that did not recover (30.3 months) it. Patients younger than 50 years showed better recovery of thumb opposition than patients older than 50 years.

Ebata and the researchers studied 109 hands with undetectable abductor pollicis brevis compound muscle action potentials (APB-CMAPs) that were treated with carpal tunnel release between 2001 and 2010 and had at least 1-year follow-up. They conducted clinical and electrophysiological examinations to determine APB-CMAPs, thumb opposition, disease duration and distal motor latency. They assessed thumb opposition by having patients perform a pulp pinch between their thumbs and middle fingers.

Reference:

Ebata T. Postoperative follow-up of severe carpal tunnel syndrome: does thumb opposition recover? Presented at: the American Society for Surgery of the Hand Annual Meeting; Sept. 6-8; Chicago.

Disclosure: Ebata has no relevant financial disclosures.

Perspective

Kevin C. Chung, MD

This study challenges our traditional belief that limitation in thenar atrophy and no functional muscle with opposition to the middle finger and that these patients will have little chance of recovery. However in this series, 53% of the patients, despite having no electric signal on needle insertion, retained some type of muscle function on clinical examination. This is an interesting finding that challenges traditional belief.

Kevin C. Chung, MD

University of Michigan Health System

Ann Arbor, Mich.

Disclosures: Chung has no relevant financial disclosures.