The Effect of Extracorporeal Shock Wave Therapy on Pain Intensity and Neck Disability for Patients With Myofascial Pain Syndrome in the Neck and Shoulder

OBJECTIVE: The aim of the study was to investigate the efficacy of extracorporeal shock wave therapy on myofascial pain syndrome in the neck and shoulder compared with that of other treatments. DATA SOURCES: PubMed, Embase, and Web of Science were systematically searched until May 30, 2019, to select randomized controlled trials. REVIEW METHODS: The randomized controlled trials comparing extracorporeal shock wave therapy with sham extracorporeal shock wave therapy or other treatments for patients with myofascial pain syndrome in the neck and shoulder patients were included. Two reviewers independently identified eligible studies. The Cochrane Handbook was used to evaluate the methodological quality of the included randomized controlled trials. Main outcomes associated with pain intensity, pressure pain threshold, and neck disability were selected. The study was registered with PROSPERO (Registration Number CRD 42019137459). RESULTS: A total of 11 randomized controlled trials were finally included. The results indicated that extracorporeal shock wave therapy had a large effect size on improving pain intensity (standardized mean difference [SMD] = 0.67, 95% confidence interval = 0.11 to 1.23, P = 0.02) and pressure pain threshold (SMD = 1.19, 95% confidence interval = 0.27 to l2.12, P = 0.01) at postintervention. However, there was no significant effect on neck disability at postintervention (SMD = 0.03, 95% confidence interval = -0.76 to 0.83, P = 0.93). After the subgroup analyses on the type of extracorporeal shock wave therapy, focused extracorporeal shock wave therapy had a significant effect on improving pain intensity (SMD = 0.75, 95% confidence interval = 0.13 to 1.36, P = 0.02) and pressure pain threshold (SMD = 1.70, 95% confidence interval = 0.21 to 3.18, P = 0.03) at postintervention in comparison with that of other treatments. CONCLUSIONS: Extracorporeal shock wave therapy is superior to other treatments in terms of alleviating the pain intensity and pressure pain threshold of patients with myofascial pain syndrome in the neck and shoulder at postintervention. In particular, focused extracorporeal shock wave therapy shows significant improvement in pain relief. However, radical extracorporeal shock wave therapy for myofascial pain syndrome treatment still remains unclear.