Neuroanatomical changes in the median nerve following surgical release in moderate-to-severe carpal tunnel syndrome

Abstract

Objective To primarily assess neuroanatomical changes following CTS surgical release and their association with patient symptoms and functional status; secondarily, to determine the optimal time point for evaluating therapeutic outcomes. Design Prospective quasi-experimental study with a follow-up period of 6 months. Setting Physical medicine and rehabilitation institutional practice in an outpatient setting. Participants 34 patients diagnosed with moderate-to-severe CTS by ultrasound, who underwent surgical release between May 2022 and July 2023. Interventions Median nerve surgical release. Main Outcome Measures Ultrasound was used to assess the cross-sectional area (CSA) and flattening ratio (FR) of the median nerve before surgery and at 15 days, three months, and six months postoperatively. The Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) was administered to assess symptom severity and functional status. Results Of the participants, 73.6% were women, with a median age of 48.8 years (42.5–53.3). Before surgery, CSA at the carpal tunnel inlet measured 14.3 mm² (IQR 13–17) and at the outlet 10 mm² (IQR 9–11); the FR was 3.1 (2.5; 3.7). The CSA at the inlet was the only parameter to show consistent improvement at all follow-up points: 15 days (p=0.001), three months (p<0.001), and six months (p<0.001). BCTQ scores for symptom severity and functional status showed significant reduction at three and six months (p<0.001). Conclusion A reduction in the elevated CSA of the median nerve was observed following CTS surgical release, with the optimal evaluation point being three months postoperatively. This anatomical improvement was associated with decreased symptom severity and improved functional status.