Latent Myofascial Trigger Point Injection Protocol

The drugs used for latent MTrPs injection containing vitamin B₁₂ (JinYao Corp, Tianjin City, China; 2 ml:1 mg), 2% lidocaine injection (ZhaoHui Corp, Shanghai City, China; 5 ml:100 mg), and compound betamethasone injection (MSD Merck Sharp & Dohme AG, Switzerland; 1 ml: 5 mg betamethasone dipropionate and 2 mg betamethasone sodium phosphate) were diluted to 20 ml with 0.9% saline for a single injection. Injection of latent MTrPs was performed using needle 25 (0.5 mm × 36 mm) and a 20 ml syringe (We Go Corp, Weihai City, China).
The latent MTrPs were mainly found in the sternoclavicular joint, sternocleidomastoid, medial or lateral pterygoid muscles, and splenius capitis muscles by palpation (Figure 1). However, it was difficult to palpate when some trigger points were hidden in muscles, and the final therapeutic effects depend on the accuracy of palpated points (16 (link)). Accurate signs of latent MTrPs can be confirmed by the patient showing “jumping signs,” which may include head retraction, fascial (or forehead) wrinkles, verbal responses, or local twitch responses (LTRs) (11 (link), 12 (link)). Palpation and injection of latent MTrPs were performed according to Travell and Simons’ “Trigger Point Manual” (17 ).