Report of Two Cases of Anterior Interosseous Nerve Palsy and Posterior Interosseous Nerve Palsy with an Hourglass-like Constriction

Abstract

We reported 2 cases of spontaneous anterior interosseous nerve (AIN) palsy and posterior interosseous nerve (PIN) palsy.
The AIN and PIN were almost normal in appearance but the hourglass-like constriction was found after interfascicular neurolysis.
The constrictive neuropathy was suggested to be the result of edema and mechanical stress from repeated elbow and/or forearm motions.
The nerve functions recovered after interfascicular neurolysis. Resection of the constricted part followed by suturing the cut ends or nerve graft was not necessary.
When the AIN and PIN are explored, interfascicular neurolysis should be performed to confirm the hourglass-like constriction.