The effect of disease activity on lumbar paraspinal muscles, psoas muscle volume and fatty degeneration in patients with ankylosing spondylitis Disease activity effects on muscles volume and fatty degeneration in ankylosing spondylitis

Abstract

Abstract Background In AS, the paravertebral muscles can deteriorate due to reduced spinal mobility, leading to muscle atrophy and fatty degeneration.Objective To identify the effects of disease activity on lumbar paraspinal muscles (multifidus, erector spinae) and psoas muscle volume and fatty infiltration in patients with ankylosing spondylitis.Methods The study involved 35 ankylosing spondylitis patients and 25 healthy controls. Pain, disease activity, and functional status were assessed using VAS, BASDAI, and BASFI respectively. MR imaging compared CSA and fat infiltration at L5 level of paraspinal muscles (multifidius, erector spinae) and psoas major muscles between AS and healthy groups.Results The mean age of the patients included in the study was 31.54 ± 11.04 in the AS group and 29.04 ± 7.26 in the HC group (p > 0.005). The mean disease duration in the AS group was 3.81 ± 2.82 years. There was no significant difference in age, body weight, height and body mass index between the AS group and healthy control group. There was a significant difference between the right MF, ES and left ES in the AS group compared to the HC group in terms of CSA measurements of the paraspinal muscles.Conclusion Inflammation, fibrosis, immobilization and postural changes in low back pain in ankylosing spondylitis contribute to atrophic changes in the paravertebral muscles.