Evaluation of lumbar erector spinae muscle tone, stiffness and elasticity in patients with chronic low back pain

Objective: To determine the tone, stiffness and elasticity of the erector spinae muscles in patients with chronic low back pain and to evaluate its associations with clinical variables. Material and Method: Between January and June 2016, a total of 138 patients with chronic low back pain were evaluated. Seventy patients with chronic lumbar strain (CLS group), 68 patients diagnosed with spondyloarthropathy (SPA group) and 42 controls without low back pain were evaluated. Muscle tone, stiffness and elasticity measurements were performed with a myotonometer device (MyotonPro) from the lumbar and thoracic erector spinae muscles. Spinal metric evaluations and questionnaires evaluating pain, disability and general health status were performed in the patient groups. Results: Demographic characteristics of the groups were similar. There was a significant difference among groups in terms of lumbar stiffness and elasticity. Elasticity was lower and stiffness was higher in the patient groups compared to the control group. However, no significant differences were detected between CLS and SPA groups. Regarding the thoracic measurements, there was also no significant difference in myotonometric values. When we evaluate the results of the lumbar measurements according to gender, muscle tone and stiffness (right) were significantly higher in males, and the elasticity (left) was significantly lower in females in the control group. No significant difference in stiffness was detected in the CLS group, whereas elasticity and tone were higher in males. In the SPA group, tonus, stiffness, and elasticity (right) were higher in males than females. Conclusions: Lumbar erector spinae stiffness was high and elasticity was found to be low in both patient groups. Regardless of the nature of pain (inflammatory or mechanic origin), similar treatment strategies-along with the primary treatment- can be tailored to treat increased stiffness. Myotonometric measurements can be used to evaluate the efficacy of these treatment approaches objectively. Keywords: Erector spinae muscle, low back pain, myofascial stiffness, myotonometry, spondyloarthropathy,