Saeid Bahramian - School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
Kiarash Salimi - School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
Majid Rezvani - Department of Neurosurgery, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Background: Low back pain is an important health problem and is one of the main symptoms in lumbar disc pathology. It is not known whether paraspinal muscular weakness is a cause or a result of low back pain.Objectives: The current study was performed in order to investigate paraspinal muscles Cross-Section Area (CSA) and Fat Infiltration (FI) in chronic versus acute Low Back Pain (LBP) patients and their association with disc herniation.Methods: ۷۶ acute and ۷۶ chronic LBP adult subjects who were candidates for magnetic resonance imaging in a referral hospital in Isfahan, Iran, were evaluated in terms of demographics, their pain and disability severity, FI (signal intensity index) of paraspinal muscles in five lumbar levels, CSA of paraspinal muscles in five lumbar levels and disk herniation degree in five lumbar levels.Results: Overweight patients: ۳۴ (۴۵.۹ %); obese: ۱۲ (۱۶.۲ %); ODI score: ۲۵.۲ (۶.۷) and mean VAS score was: ۶.۴۴ (۱.۲). The longer the pain persisted, the higher its severity was felt. Similar numbers were found for females. Females had higher pain scores and higher FI in paraspinal muscles. Accordingly, FI was higher, and CSA was lower in chronic LBP than acute LBP (P<۰.۰۵). Women had smaller, and fattier paraspinal muscles (P<۰.۰۵).Conclusion: Chronic LBP is associated with a decreased muscle volume in paraspinal muscles. Regular physical activity routines, weight loss meal plans, physiotherapy and corrective training programs might prevent chronicity of LBP, increase paraspinal CSA, decrease paraspinal FI, attenuate back pain severity and hence improve patients’ quality of life.

Lumbar spine, Muscle Fat Replacement, Muscular Atrophy, Magnetic resonance imaging, Paraspinal Muscle, Low back pain