Carpal Tunnel Syndrome Treatment and the Subsequent Alterations in Median Nerve Transverse Mobility

Objectives: The mobility (transverse movement) of the median nerve (MN) is decreased in patients with carpal tunnel syndrome and can be measured noninvasively by ultrasound. To date, there are few prognostic features to help predict the outcome of 2 commonly performed treatments: surgical carpal tunnel release and corticosteroid injection. This study aimed to assess the changes in nerve mobility after the intervention and to correlate this with treatment and the disease severity. Methods: A total of 181 patients with carpal tunnel syndrome with different electrophysiologic severities were recruited and assessed by dynamic ultrasound scanning of the MN before and after treatment. The dynamic ultrasound images were collected while the patients performed finger and wrist flexion. Results: For both injection and carpal tunnel release, the nerve displacement increased with wrist flexion, from a mean ± SD of 7.0 ± 2.4 to 7.9 ± 2.7 mm (P <.005). Patients who underwent surgery showed greater improvement (P <.005) in nerve mobility compared to those who underwent injection. We also observed that the increase in nerve mobility was predominantly in patients with more nerve damage at baseline. Conclusions: This study shows that the dynamic behavior of the MN changes in response to treatment and lays a foundation for future studies to assess the prognostic potential of nerve mobility measurement.