Management of recurrent carpal tunnel syndrome with microneurolysis and the hypothenar fat pad flap

Abstract

A retrospective chart review for the period between 1998 and 2006 was conducted to evaluate microneurolysis combined with a hypothenar fat pad flap (HTFPF) for patients at Mayo Clinic, Scottsdale, Arizona, who were being treated for recurrent carpal tunnel syndrome. After exclusion of patients with incomplete release of the transverse carpal ligament at the time of the original operation, 28 consecutive patients were identified. Their average age was 68.5 years (range 43-89 years). The average interval between the original carpal tunnel release and reexploration was 82 months (range 5-298 months). The average follow-up was 10.5 months (range 3-48.4 months). The preoperative two-point discrimination tests averaged 7 mm (range 5-12 mm). At surgery, all patients were found to have fibrosis surrounding the median nerve with adherence of the nerve to the radial leaf of the transverse carpal ligament. After surgery, the Tinel sign disappeared in 26 of 28 patients and two-point discrimination improved to an average of 6 mm (range 4-8 mm). Postoperative grip strength averaged 20 kg, compared with 11 kg preoperatively. Pain completely disappeared in 83% of patients (average improvement 93%, range 5-100%). Numbness completely disappeared in 42% of patients (average improvement 82.9%, range 5-100%). Tingling disappeared in 50% of patients (average improvement 84.7%, range 5-100%). No patient reported being worse after reoperation. These results suggest that the combination of microneurolysis and HTFPF can restore median nerve gliding and provide soft-tissue coverage, improving symptoms in patients with recurrent carpal tunnel syndrome.

Figure 1

A and B, Operative findings consistently demonstrated adhesion of the nerve to the radial border and roof of the carpal tunnel. C, Under microscope magnification, a complete external microneurolysis was performed throughout the entire zone of scarring to the level of normal fascicular anatomy. (Used with permission of Mayo Foundation for Medical Education and Research).

Figure 2

A and B, Recurrent fibrosis prevented nerve mobility or gliding in all patients. After microneurolysis, the nerve should be mobile and free of tension during wrist range of motion.

Figure 3

A hypothenar fat pad flap procedure was performed by first identifying the ulnar nerve proximally and distally. A, The ulnar leaf was resected. (Used with permission of Mayo Foundation for Medical Education and Research.) B, The flap was then transferred onto the median nerve and attached with several stitches to the radial wall of the carpal canal at the level of the flexor pollicis longus tendon.