Efficacy of different doses of platelet-rich plasma for moderate carpal tunnel syndrome: study protocol for a prospective, randomized, controlled trial in Guangzhou, China.

backgroundCarpal tunnel syndrome (CTS) is the most prevalent peripheral nerve disorder, with a reported lifetime prevalence of approximately 8% in the general population, and higher rates observed in females than in males (approximately 10% vs. 5.8%), based on global epidemiological estimates. Recently, Platelet-rich plasma (PRP) injections have attracted increasing attention as an innovative treatment, proving more effective than corticosteroids and dextrose. However, the optimal PRP therapeutic dosage remains unclear. This study aims to determine if a 5 mL (vs. 3 mL) platelet-rich plasma injection around the median nerve more effectively relieves symptoms in moderate carpal tunnel syndrome patients.

methodsThis prospective, double-blind, randomized, parallel-group, superiority-controlled trial will be conducted at the Third Affiliated Hospital of Southern Medical University (a tertiary academic hospital) in Guangzhou, China. Trained rehabilitation physicians in the outpatient department of Rehabilitation Medicine, will recruit 60 adults with moderate CTS and obtain informed consent. Participants will be randomly assigned (a 1:1 ratio) to receive either 3 mL or 5 mL PRP injection under ultrasound guidance at baseline and at 2 weeks. Eligible participants are adults aged 20-80 years with electromyography (EMG)-confirmed moderate CTS, a numbness score ≥ 40 mm on a 100-mm Visual Analogue Scale (VAS). Additionally, all injections will be performed by physicians who have completed advanced training in ultrasound-guided peripheral nerve injection procedures and all participants will receive standardized health education from licensed physiotherapists with at least three years of specialized experience. The primary outcome is the change in the VAS score of numbness from baseline to 6 months. Secondary outcomes include changes in ultrasound parameters (cross-sectional area (CSA), blood flow of median nerve (MNBF), and swollen rate of median nerve (MNSR)), Boston Carpal Tunnel Syndrome Questionnaire-Symptom Severity Scale (BCTQ-SSS), Boston Carpal Tunnel Syndrome Questionnaire-Functional Status Scale (BCTQ-FSS), electrophysiological measures (sensory nerve conduction velocity (SNCV), distal motor latency (DML)). Safety outcomes include all adverse events (AEs) and injection-related complications recorded throughout follow-up. Data will be analyzed by using intention-to-treat and per-protocol approaches. All analyses will be performed using IBM SPSS Statistics software. DISCUSSION: The results of this study will evaluate the efficacy of different doses of PRP injection in the treatment of moderate CTS, thereby providing suggestions on the optimal dose for injection therapy and offering guidance for clinical application.

trial registrationChinese Clinical Trial Registry (ChiCTR2400094746). Retrospectively registered on 26 December 2024. https://www.chictr.org.cn/showproj.html?proj=252770 . The first participant was enrolled on 30 September 2024.