Myofascial Pain Syndrome in Chronic Back Pain Patients

Background: Myofascial pain syndrome (MPS) is a regional musculoskeletal pain disorder that is caused by myofascial trigger points. The objective of this study was to determine the prevalence of MPS among chronic back pain patients, as well as to identify risk factors and the outcome of this disorder. Methods: This was a prospective observational study involving 126 patients who attended the Pain Management Unit for chronic back pain between 1st January 2009 and 31st December 2009. Data examined included demographic features of patients, duration of back pain, muscle(s) involved, primary diagnosis, treatment modality and response to treatment. Results: The prevalence of MPS among chronic back pain patients was 63.5% (n = 80). Secondary MPS was more common than primary MPS, making up 81.3% of the total MPS. There was an association between female gender and risk of developing MPS ($x^2$ = 5.38, P = 0.02, O.R. = 2.4). Occupation, body mass index and duration of back pain were not significantly associated with MPS occurrence. Repeated measures analysis showed significant changes (P < 0.001) in Visual Analogue Score (VAS) and Modified Oswestry Disability Score (MODS) with standard management during three consecutive visits at six-month intervals. Conclusions: MPS prevalence among chronic back pain patients was significantly high, with female gender being a significant risk factor. With proper diagnosis and expert management, MPS has a favourable outcome.