Extended Therapeutic Effect of 35kDa Hyaluronan Fragment Injection in Patients With Chronic Pain Caused by Myofascial Pain Syndrome

HA35/B-HA injection (Registration number L20200708MP07707; Ministry of Health). The subjects can continue to take oral analgesics during the treatment period, and the comparison of the dose and interval days of the analgesics before and after the treatment can also be used as the effect judgment of the injection.