Trigger Point Injections: a Systematic, Narrative Review of the Current Literature

Myofascial pain syndrome (MPS) is a frequently encountered cause of chronic pain for patients in both primary and specialty clinics. When conservative methods fail, many patients resort to trigger point injections (TPI) or needling therapies to alleviate their pain. Though MPS has a high prevalence and injections are frequently performed, there is no consensus to date regarding the optimal solution for injection or the superiority of injection versus needling alone. This narrative review includes randomized controlled trials performed over the last 15 years that evaluated the efficacy of trigger point injections of LA (LA), botulinum toxin A (BTXa), or dry needling for the relief of MPS. A total of 13 studies were included and evaluated for reduction of pain, adverse events (AE), and other secondary outcomes. Local anesthetics, BTXa, and dry needling all significantly reduced pre-treatment pain levels, but overall there was no significant difference between groups. Botulinum toxin A was the most expensive treatment and was associated with more AEs, but they were all mild and self-limiting in nature. Dry needling had a significantly higher rate of post-treatment muscle soreness than those injections that included LA. Local anesthetic, BTXa, and dry needling are all reasonable treatments for MPS. However, given the reduced cost and lower rate of muscle soreness associated with LA injection, it may be considered first line therapy for patients with MPS requiring TPI.