Are the palmar cutaneous nerves safe during standard carpal tunnel release ?

An incision in the axis of the ring finger is thought to be the safest for carpal tunnel release based on cadaveric studies that suggest that the palmar cutaneous nerves do not cross into this area. Despite the use of this incision, persistent postoperative scar tenderness has been reported in up to 36% of patients following standard carpal tunnel release. For this reason, an investigation was undertaken to determine the presence of palmar cutaneous nerves in this incision. Random biopsies of transversely oriented fibrous bands in the subcutaneous tissue were taken during 15 open carpal tunnel releases. In every patient, at least one biopsy was positive for peripheral nerve tissue. These findings, combined with previous cadaveric studies, suggest that a "safe" palmar incision that will avoid injury to palmar cutaneous nerves does not exist. Carpal tunnel release techniques that avoid a palmar incision may lessen postoperative morbidity by avoiding injury to these small cutaneous nerves.