MRI assessment of recurrent carpal tunnel syndrome after open surgical release of the median nerve.

OBJECTIVE: The purpose of this study was to retrospectively determine the accuracy of MRI in identification of the morphologic features of median nerve dysfunction after surgical release of the median nerve for carpal tunnel syndrome.

MATERIALS AND METHODS: Two blinded readers independently evaluated axial 1.5-T MR images for retinacular regrowth, morphologic characteristics of the median nerve, and presence of mass effect, fibrosis, and carpal tunnel decompression. All 47 patients (11 men, 36 women; mean age, 55 years; range, 27-81 years) had undergone open surgical release of the median nerve for carpal tunnel syndrome. Thirty-five patients had electromyographic evidence of recurrent carpal tunnel syndrome. The other 12 patients did not have electrophysiologic evidence of recurrent carpal tunnel syndrome and were the control group.

RESULTS: A statistically significant difference between the recurrent carpal tunnel syndrome and control groups was found for fibrosis (p = 0.009), nerve enhancement (p = 0.04), and median nerve width (p = 0.008) and ratio (p = 0.01) at the pisiform level.

CONCLUSION: MRI may be used in association with electromyography for accurate postoperative evaluation of the carpal tunnel.