The use of the palmaris brevis flap in recurrent carpal tunnel syndrome.

In failed cases of primary carpal tunnel release, the addition of the highly vascular palmaris brevis turnover flap as an adjunct to internal neurolysis discourages scarring and provides a nutrient bed for axonal regeneration. In fact, the palmaris muscle flap actually may suppress the growth of nerve fibers into the overlying scar. Experimentally, classic neuromas do not form when a severed nerve is placed in an innervated muscle, particularly those with minimal excursion, as is the case with the turned over palmaris cushion. Major advantages of the palmaris turnover muscle are (1) proximity of the muscle to the operative field, obviating the need for a distant graft source; (2) negligible functional motor loss as a result of forfeiting this muscle; (3) no separate scar is created in raising this flap; and (4) adequate padding of the subcutaneous fat is still left at the donor site to protect the ulnar neurovascular bundle. Although postoperative healing and rehabilitation time are relatively lengthened by the more extensive dissection, subjective assessments of pain relief and clinical improvements in grip strength, pinch strength, and sensory parameters justify the use of the palmaris brevis turnover flap in recalcitrant carpal tunnel cases.