Relationship between paraspinal muscle fat infiltration ratio and lumbar-pelvic parameters in patients with chronic non-specific low back pain

English Keywords:Chronic non-specific low back pain  Fat infiltration ratio  Lumbar-pelvic parameters

English Abstract:

  【Abstract】 Objectives: To compare and explore the relationship between the lumbar paraspinal muscle fatty infiltration ratio(FIR) and lumbar-pelvic parameters of unilateral and bilateral chronic non-specific low back pain(CNLBP). Methods: A total of 28 patients with bilateral CNLBP(group A), 20 patients with unilateral CNLBP(group B), and 20 volunteers without low back pain(group C) were included. The FIR and FIR asymmetry(FIRasy) of paraspinal muscles in L3/4, L4/5 and L5/S1 segments were measured on lumbar MRI. Lumbar-pelvic parameters were measured on standing radiographs, including coronal pelvic obliquity(PO), lumbar lordosis(LL), pelvic incidence(PI), pelvic tilt(PT) and sacral tilt(SS). The muscle FIRs in patients with unilateral and bilateral CNLBP were observed, and the differences of FIRs between CNLBP and control group were compared. Meanwhile the differences of lumbar-pelvic parameters between two groups with CNLBP were also compared. The correlation between FIR and lumbar-pelvic parameters was analyzed by Pearson correlation. Results: There was no significant difference in age, gender ratio and body mass index(BMI) among the three groups(P>0.05). In group A, there were significant differences in the FIR of psoas major(PM) muscle on the left and right sides of L4/5, L5/S1 and FIR of L4/5 erector spines(ES)(P<0.05). In group B, the FIRs between painful and non-painful sides were not significantly different(P>0.05). Compared with group C, the FIR of multifidus(MF) in group A and B was higher(P<0.05). There was no significant difference in PO, LL, PI, PT, SS between group A and group B(P>0.05). In group A, LL was negatively correlated with FIR of L3/4 left PM and FIRasy of L5/S1 PM(r=-0.460, -0.425, P<0.05), and positively correlated with FIRasy of L3/4 MF(r=0.459, P<0.05); SS was negatively correlated with FIR of L3/4 left PM(r=-0.496, P<0.05). In group B, PI and PT were positively correlated with FIRasy of L5/S1 PM(r=0.490, 0.516, P<0.05); LL and SS were positively correlated with FIRasy of L4/5 ES(r=0.503, 0.523, P<0.05). Conclusions: CNLBP patients showed higher fatty infiltration in multifidus muscle. The FIR symmetry of lumbar paraspinal muscles was different in unilateral and bilateral CNLBP patients. And there was a certain correlation between the asymmetrical fatty of lumbar paraspinal muscles and the lumbar-pelvic findings in the sagittal plane.