New mini-invasive decompression for pronator teres syndrome.

The pronator teres syndrome is a set of signs and symptoms that result from compression of the median nerve in the upper forearm. It is a dynamic syndrome that is frequently associated with compression of the same nerve at the carpal tunnel. The literature describes different anatomic structures that can cause this syndrome. Experience showed us that the deep fascia of the superficial head of the pronator teres is the only anatomic structure that causes compression of the median nerve in the upper forearm. If the flexor digitorum test is negative, selective release of the deep fascia of the superficial head of the pronator teres ends the symptoms. Our surgical technique uses a mini-invasive approach that takes into account the anatomic knowledge of this region. A 3.5-cm oblique skin incision is done 6 cm distal to the medial epicondyle, over the flexor/pronator muscle mass. The medial cutaneous nerve is atraumatically retracted. The superficial fascia of the flexor/pronator muscles is opened transversely. With the section of the septum between the pronator teres and the flexor carpi radialis, access to the deep fascia of the superficial head of the pronator teres is obtained. This structure is released. The median nerve is now easily visualized, and other types of possible compression causes are excluded. The same surgeon treated 44 cases with this technique. Two assistants were always needed for this mini-invasive approach. Pronator teres symptoms disappeared in 93% of cases.