Evaluating the Prevalence of Lumbar Myofascial Pain Syndrome in Patients with Non-specific Chronic Low Back Pain and a Normal MRI Study

Low back pain is a very common disorder that affects a significant percentage of people in the community (1). As a non-mechanical cause, myofascial pain is a primary disorder which may produce lumbar and lower limb pain and is not necessarily secondary to other diagnosis (2-5). Trigger points are the main symptoms of myofascial pain which may mimic the radicular pain in spinal disorders (6, 7).

To evaluate the prevalence of lumbar myofascial pain syndrome in patients with non-specific chronic low back pain and a normal MRI study.

This cross-sectional study was conducted on 171 patients with chronic low back pain and normal MRI report (age:43.96 ±13.6years), (weight:76.7± 71.74 kg), ( height: 166.44 ± 7.15 cm). Incidence of this syndrome was evaluated in 16 lumbar and lower extremity muscles (8). The trigger points finding was performed by tissue palpation (9).

Females constituted 71.7 % and males 28.3 % of the participants. The patients maximum incidence percentages were in quadratus lumborum (47.7℅)‚ multifidus(43℅)‚ gluteus medius (36℅)‚ gluteus maximus (34.9℅)‚ piriformis (32.4℅) and other muscles involvement was below 30℅. In 27.7% of the patients only two muscles were involved. A significant correlation was shown between the number of involved muscles and age(r=0.21, p=0.005) and pain and disability(r=0.46, p=0.03).

Myofascial pain syndrome should be considered as a hallmark in differentiating chronic low back pain regardless of MRI finding.