Aims. The presence of facet tropism has been correlated with an elevated susceptibility to lumbar disc pathology. Our objective was to evaluate the impact of facet tropism on chronic lumbosacral discogenic pain through the analysis of clinical data and finite element modelling (FEM). Methods. Retrospective analysis was conducted on clinical data, with a specific focus on the spinal units displaying facet tropism, utilizing FEM analysis for motion simulation. We studied 318 intervertebral levels in 156 patients who had undergone provocation discography. Significant predictors of clinical findings were identified by univariate and multivariate analyses. Loading conditions were applied in FEM simulations to mimic biomechanical effects on intervertebral discs, focusing on maximal displacement and intradiscal pressures, gauged through alterations in disc morphology and physical stress. Results. A total of 144 discs were categorized as ‘positive’ and 174 discs as ‘negative’ by the results of provocation discography. The presence of defined facet tropism (OR 3.451, 95% CI 1.944 to 6.126) and higher Adams classification (OR 2.172, 95% CI 1.523 to 3.097) were important predictive parameters for discography-‘positive’ discs. FEM simulations showcased uneven stress distribution and significant disc displacement in tropism-affected discs, where loading exacerbated stress on facets with greater angles. During varied positions, notably increased stress and displacement were observed in discs with tropism compared to those with normal facet structure. Conclusion. Our findings indicate that facet tropism can contribute to disc herniation and changes in intradiscal pressure, potentially exacerbating disc degeneration due to altered force distribution and increased mechanical stress. Cite this article: Bone Joint Res 2024;13(9):452–461

Cervical spine facet tropism (CFT) defined as the facets’ joints angles difference between right and left sides of more than 7 degrees. This study aims to investigate the relationship between cervical sagittal alignment parameters and cervical spine facets’ tropism. A retrospective cross-sectional study carried out in a tertiary center where cervical spine magnetic resonance imaging (MRI) radiographs of patients in orthopedics/spine clincs were included. They had no history of spine fractures. Images’ reports were reviewed to exclude those with tumors in the c-spine. A total of 96 patients was included with 63% of them were females. The mean of age was 45.53± 12.82. C2-C7 cobb's angle (CA) and C2-C7 sagittal vertical axis (SVA) means were −2.85±10.68 and 1.51± 0.79, respectively. Facet tropism was found in 98% of the sample in at least one level on either axial or sagittal plane. Axial C 2–3 CFT and sagittal C4-5 were correlated with CA (r=0.246, P 0.043, r= −278, P 0.022), respectively. In addition, C2-C7 sagittal vertical axis (SVA) was moderately correlated with axial c2-3 FT (r= −0.330, P 0.006) Also, several significant correlations were detected in our model Cervical vertebral slopes and CFT at the related level. Nonetheless, high BMI was associated with multi-level and multiplane CFT with higher odd's ratios at the lower levels. This study shows that CFT at higher levels is correlated with increasing CA and decreasing SVA and at lower levels with decreasing CA. Obesity is a risk factor for CFT

Aims

The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort.

Aim:. The purpose of this study was to identify factors (radiographic and MRI) which may be important in determining whether a degenerative spondylolisthesis at L4/5 is mobile. Method:. We identified 60 consecutive patients with a degenerative spondylolisthesis(DS) at L4/5 and reviewed their imaging. Patients were separated into groups on the basis of whether the DS was mobile (group A) or non-mobile (Group B) when comparing the upright plain lumbar radiograph to the supine MRI. We assessed the lumbar lordosis, pelvic incidence, sacral slope, pelvic tilt, grade of the slip, facet angles at L4/5, facet tropism, facet effusion size, facet degenerative score (cartilage and sclerosis values) and disc degenerative score (Pfirrmann) at L4/5. Results:. There were 40 patients in group A and 20 in group B. Mean age for group A was 69.2 years and for group B was 66.2 years. The difference was not significant (p-0.27; 95% CI 2.5–8.7). No significant differences were found between groups for pelvic incidence (p-0.75; 95% CI 4.6–6.3), pelvic tilt (p-0.62; 95% CI 3.2–5.3), sacral slope (p-0.51; 95% CI 3.2–6.5), lumbar lordosis (p-0.46; 95% CI 9.5–4.3), degree of facet tropism (p-0.4) and magnitude of the facet effusions (p-0.1). Facet angle differences between groups approached significance (p-0.058; 95% CI 0.1–6.7). Significant differences between groups were found in cartilage degenerative score (p-0.002), facet sclerosis grade (p-0.00) and disc degenerative score (p-0.00). In group B 10 out of 20 (50%) reduced fully and were not apparent on the MRI only. Conclusions:. Sagittal pelvic parameters do not play a significant role in differentiating between mobile and non-mobile DS at L4/5. Mobile DS tends to be associated with more sagittally orientated facets, lower Pfirmann grade, lower facet cartilage and sclerosis degenerative scores. Standing plain lumbar radiographs are essential in all patients over the age of 40 years in order not to miss up to 17% of DS at L4/5. Conflict Of Interest Statement: No conflict of interest

We carried out a study to determine the effect of facet tropism on the development of adolescent and adult herniation of the lumbar disc. We assessed 149 levels in 140 adolescents aged between 13 and 18 years and 119 levels in 111 adults aged between 40 and 49 years with herniation. The facet tropism of each patient was measured at the level of the herniated disc by CT. There was no significant difference in facet tropism between the herniated and the normal discs in both the adolescent and adult groups, except at the L4-L5 level in the adults. Facet tropism did not influence the development of herniation of the lumbar disc in either adolescents or adults

Introduction: The effect of facet tropism on the development of lumbar disc diseases has been investigated but is still controversy; moreover, there has been no study to be done on far lateral lumbar disc herniation (LDH). In the current study, the authors attempted to determine the differences of the degree of facet tropism and the degree of disc degeneration between far lateral and posterolateral LDHs. In addition, the effect of the difference of degree of facet tropism and the degree of disc degeneration on the development of far lateral LDH was investigated compared with posterolateral LDH. Methods: 38 LDHs (far lateral, n = 19; posterolateral, n = 19) who underwent posterior open discectomy or paraspinal approach were included in this study. The mean age was 52.3 years in far lateral LDH and 45.3 years in posterolateral LDH. The degrees of facet tropism and disc degeneration were measured at herniated disc level using MRI, and compared for the two different types of LDHs. Mann-Whitney U test and Spearman test were used for analysis. Results: There were significant statistical differences in the degree of facet tropism and the degree of disc degeneration. There was no significant correlation between the degree of facet tropism and the degree of disc degeneration in far lateral LDH. Discussion: The current study suggests that the differences of the degree of facet tropism and the degree of disc degeneration might be considered as the key factors to determine the development of far lateral LDH compared with posterolateral LDH