Thursday Conference Content

From the archives: Trigger points for pain control with Dr. Christine Collins

Question: Do trigger point injections with lidocaine lead to lowering pain for patients with point tenderness in their neck or back when compared to standard therapies?

Clinical Importance? Musculoskeletal neck and back pain can pose a challenge to treat when patients do not respond to NSAIDs or have a contraindication to NSAID use, and trigger point injections pose a solution to this. 

Yanuck et al: This is a single blind, prospective, randomized trial conducted at a single level I academic Emergency Department (n=62) with the goal to assess whether trigger point injection with 1% lidocaine results in decreased pain scores when compared to conventional therapy in the treatment of myofascial pain syndrome of the neck/back. For the primary outcome, the mean difference in NRS score when comparing trigger point to control was reported as a statistically significant different (ANCOVA, F[1,50]=25.97, p<0.001). The length of ED stay was also statistically lower in the trigger point injection group. Finally, trigger point injection patient received less opioid prescriptions compared to standard therapy. 

Limitations:  not double blinded, study personnel were in room with treating physician while doing injections, variability in competence of treating physicians, no sample size calculated before the study was done, loss of study participants/drop-outs (especially in the control arm), no tests run for normality of data, pain scores reported as means (outliers can significantly affect), “standard therapies” were broad and not clearly discussed or reported, significant amount of opioid prescriptions, convenience sampling limiting generalizability, 20 minute timeline may have favored injections over other therapies, no follow up period after ED, did not discuss adverse events or side effects reported   

Kocak et. al: This is a randomized prospective study (n=80) at a single Emergency Department which aimed to compare trigger point injections with 2% lidocaine to IV NSAID (dexketoprofen) in the treatment of lower back pain.The study found a statistically significant difference in pain scores reported by the trigger point injection group and the NSAID group (mean pain score trigger point: 7.55, NSAID 7.22, p<0.05), with a significantly higher response to treatment recorded in the trigger point group, with 21 out of 22 responding to trigger points and only 20 out of 32 responding to NSAIDs (p=0.008)

Limitations: Not blinded, no longer term follow up, no conclusions can be made about side effects/adverse effects, no definition of “experienced and trained professionals”

  • Although both studies supported that trigger point injections can reduce pain, both were limited. They did not follow up long enough to suggest a duration of therapeutic effect or address adverse effects adequately. Both studies also did not describe in detail a standardized training process for providers performing the injections. 
  • Trigger point injections are a promising treatment for musculoskeletal pain, however based on my review of the literature, I would not routinely use trigger point injections to treat musculoskeletal back or neck pain. More research should be dedicated to address the length of time the therapy lasts as well as adverse effects that are possible.
  1. Yanuck, Justin, et al. “Pragmatic Randomized Controlled Pilot Trial on Trigger Point Injections with 1% Lidocaine versus Conventional Approaches for Myofascial Pain in the Emergency Department.” The Journal of Emergency Medicine, vol. 59, no. 3, 2020, pp. 364–370., https://doi.org/10.1016/j.jemermed.2020.06.015. 
  2. Kocak AO, Ahiskalioglu A, Sengun E, Gur STA, Akbas I. Comparison of intravenous NSAIDs and trigger point injection for low back pain in ED: A prospective randomized study. Am J Emerg Med. 2019 Oct;37(10):1927-1931. doi: 10.1016/j.ajem.2019.01.015. Epub 2019 Jan 15. PMID: 30660342.

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