First Lumbrical Muscle Flap for Recurrence of Carpal Tunnel Syndrome: Anatomical Study and Surgical Technique

Recurrence of carpal tunnel syndrome implies the reappearance of symptoms after release surgery. If the cause of recurrence is not an incomplete release, but a traction neuritis, the tendency is to add to the revision surgery of the carpal tunnel the use of flaps to cover the median nerve. These flaps establish a physical barrier between the nerve and the rest of the adjacent structures, preventing adhesions, and providing neovascularization and better nerve sliding.In the present work, we detail a revision surgery in which the first lumbrical muscle is used as a covering flap. This flap has two benefits. Firstly, it acts as a vascularized coverage for the median nerve (avoiding the formation of fibrosis and favoring its sliding); secondly, a structure that takes up space is removed from the carpal tunnel, thus reducing the pressure within it.Along with the explanation of the technique, the present article provides a detailed description of the anatomical variability of the first lumbrical muscle and its vascularization, as well as the results of a cadaveric study on the location of the vascular pedicle of the first lumbrical muscle.