The relationship between lumbar facet joint tropism,paraspinal muscle fatty atrophy, sagittal spinopelvicparameters in subacute/chronic low back pain

In this study, we aimed to investigate the effect of PI-LL mismatch and PI parameter on FT and paraspinal muscles in patients with subacute and chronic low back pain and thus to increase our knowledge about the mechanical factors that are effective in low back pain. Our study was planned as a retrospective cross-sectional study. A total of 105 patients aged 30-65 years with non-specific low back pain for four weeks or more were included in the study. Spinopelvic angles were evaluated on lateral lumbar radiographs and facet tropism values and paraspinal muscle fatty atrophy levels were evaluated on MRI images. Patients were divided into 2 groups according to PI-LL discordance and 3 groups according to the degree of PI and the relationship between FT at each level and paraspinal muscle fatty atrophy was evaluated. VAS, ODI, IBAS scales and pain duration parameters were compared between patient groups. In addition, the presence and degree of FT were evaluated for each level in the lumbar region according to the fatty atrophy group( NM; non to modarate , MS; modarete to sever) in the paraspinal muscles at the L3-4 level. According to the results of our study, the presence of FT at L4-5 and L5-S1 levels, L5-S1 FT grade (7.1 (0.6- 34.5) vs 4.05 (0.1- 28.7)), VAS, ODI scores and pain duration were statistically significantly higher in the group with PI-LL mismatch compared to the group without mismatch (p<0.05). There was no statistically significant relationship between the degree of PI angle and the presence and degree of FT, duration of low back pain and scale scores (p>0.05). When the degree of paraspinal muscle fatty atrophy was analyzed with PI-LL mismatch, the degree of fatty atrophy in those with PI-LL mismatch (1.39 ± 0.63) was statistically significantly higher than those without mismatch (1.13 ± 0.62) for L2-3 MF muscle (p=0.039). When the degree of paraspinal muscle fatty atrophy was analyzed according to the degree of PI, the group with "decreased" degree of PI differed from the other groups and the degree of fatty atrophy was statistically significantly higher in this group (p=0.005). When FT was analyzed according to fatty atrophy of the paraspinal muscles at the L3-4 level; for the PM muscle, the presence of L1-2 FT was statistically significantly higher in the group than in the NM group (p=0,006). For the same muscle, the presence of L4-5 FT was significantly increased in the MS group, but did not reach statistical significance (p=0.076). In terms of FT angle values, the degree of L4-5 FT was statistically significantly higher in the MS group (9.9 (0.2 - 23.3)) compared to the NM group (5.75 (0 - 26.3)) (p=0.042). The degree of L1-2 FT was higher in the MS group (7.3 (0.4- 19.1)) than in the NM group (4 (0.1 - 17.3)), but did not reach statistical significance (p=0.051). Compared to the fatty atrophy groups in the L3-4 ES muscle, the L1-2 FT grade was higher in the MS group (5.1 (0.4- 19.1)) than in the NM group (3.7 (0.1- 14.5)) but did not reach statistical significance (p=0.053). For the same muscle, there was no statistically significant correlation between the presence of FT at other levels and the degree of FT (p>0.05). Compared to the fatty atrophy groups in the L3-4 MF muscle, the presence of FT at L1-2 was statistically significantly higher in the MS group than in the NM group (p=0.02). When the degree of FT for the same muscle was evaluated, the degree of L1-2 FT was statistically significantly higher in the MS group (5.9 (0.1- 19.1)) than in the NM group (3.5 (0.3- 14.5)) (p=0.009). The degree of PI angle and PI-LL mismatch may be related to both other lumbar structures that are effective in lumbar spine mechanics and low back pain. For a segment-specific interpretation of this relationship and a clear determination of its clinical significance in low back pain, studies with a larger number of patients and a control group are needed.