Assessment of predisposing factors in myofascial pain syndrome and the analgesic effect of trigger point injections - A primary therapeutic interventional clinical trial

BACKGROUND AND AIMS: Myofascial pain syndrome (MPS) is a common cause of chronic musculoskeletal pain, characterised by myofascial trigger points (TPs). TP injection is an established technique for management of MPS. In this study, we analysed the efficacy of myofascial TP injection of lignocaine and the influencing biomechanical factors on MPS. METHODS: After obtaining ethical committee approval, we included the first 100 adult patients of MPS with failed physical therapy aged above 18 years, and with TPs in the trapezius, infraspinatus, and/or the levator scapulae muscles and Visual analog scale (VAS) >4. TP injection of 2% (2 ml) lignocaine was performed. Visual analogue scale (VAS) scores were recorded immediately and after 1 month. Number of repeat TP injections and use of oral analgesic in one month was noted. Results were analysed with the analysis of variance test. RESULTS: The mean VAS reduced significantly both immediately and 1 month after therapeutic injections (8.57 ± 0.77, 2.67 ± 1.43 and 2.82 ± 1.4, respectively, P < 0.01). Keeping the palm below the head during sleep was the major contributing factor for myofascial TP, followed by slanting the neck to use mobile phones. Repeat TP injection was used in 4% of cases. CONCLUSION: TP injection of 2 ml of 2% lignocaine along with correction of predisposing biomechanical factors provided significant pain relief for MPS in patients with failed physical therapy without any side effects.