Efficacy of ultrasound-guided infiltration with levobupivacaine and triamcinolone for myofascial pain syndrome of the quadratus lumborum: a retrospective observational study

INTRODUCTION AND OBJECTIVES: Myofascial Pain Syndrome (MPS) of the Quadratus Lumborum muscle (QL) is a frequent cause of chronic low back pain. With this study, we aimed to assess the efficacy of ultrasound-guided infiltration with 0.25% levobupivacaine and 40.ßmg triamcinolone for MPS of the QL. METHODS: Observational and retrospective study of participants submitted to ultrasound-guided infiltration of the QL muscle from January 1, 2015 to June 31, 2019. Pain intensity was assessed using the five-point pain Numeric Rating Scale (NRS): pre-intervention, at 72.ßhours, 1 month, 3 months and 6 months post-intervention. Additional data collected were demographic characteristics, opioid consumption, and adverse effects. RESULTS: We assessed 90 participants with mean age of 55.2 years. Sixty-eight percent of participants were female. Compared to the pre-intervention assessment, there was an improvement in pain at 72.ßhours (Mean Difference [MD.ß=.ß3.085]; 95% CI: 2.200...3.970, p.ß<.ß0.05), at the 1st month (MD.ß=.ß2.644; 95% CI: 1.667...3.621, p.ß<.ß 0.05), at the 3(rd)month (MD.ß=.ß2.017; 95% CI: 0.202...2.729, p.ß<.ß0.05) and at the 6(th) month (MD.ß=.ß1.339; 95% CI 0.378...2.300, p.ß<.ß0.05), post-intervention. No statistically significant differences in opioid consumption were observed. No adverse effects associated with the technique were reported. CONCLUSIONS: Ultrasound-guided infiltration of the QL muscle is a safe and effective procedure for the treatment of pain in the QL MPS within 6 months post-intervention.