| BackgroundDegenerative lumbar spondylolisthesis is a common orthopedic disease,and its occurrence is closely related to the theory of "sinew-bone imbalance" in bone traumatology of Chinese medicine.In recent years,domestic and foreign scholars have gradually deepened the research on DLS,and related studies in the biomechanics,imaging and pathology of the disease are increasing day by day.Compared with other paravertebral muscles,the lumbar multifidus muscle is close to the middle of the spine and located in the spinous grooves.It has special anatomical structure and morphological characteristics of large cross-sectional area and short fiber length.It can produce greater contractile force in limited space and plays an important role in maintaining the stability of the lumbar spine.As one of the "three-joint complex" structures,the lumbar facet joint mainly plays a role in resisting the shear force of the lumbar spine.Since LFJ is a three-dimensional structure,its spatial angulation will determine the biomechanical distribution of the lumbar segment.Therefore,the change of facet joint Angle will also lead to the change of local stress.Sagittal orientation of facet joint is one of the important initial reasons for inducing DLS.In conclusion,although the pathogenesis of DLS is the result of interaction of multiple factors,the degeneration of multifidus muscle and LFJ plays an important role in the pathogenesis of DLS.Second,although current studies on the pathogenesis of DLS focus on the factors that disrupt lumbar biomechanics,such as intervertebral disc degeneration,FJA changes and paravertebral atrophy,there are still few studies to explore whether there is a correlation between the etiologies.Secondly,CT value can effectively evaluate muscle fiber density,so the degeneration of MF can be evaluated by CT value.Based on this,in the clinical research part of this project,the correlation between LFJ degeneration and CT value of multifidus muscle will be discussed retrospectively through the collection of lumbar vertebra CT examination of patients with degree Ⅰ L4/5 DLS.In the basic research part,the finite element analysis method will be used to explore the influence of strengthening multi-fidus muscle exercise on the lumbar mechanics and displacement of DLS patients.Based on this,in the clinical research part of this project,the correlation between LFJ degeneration and CT value of multifidus muscle will be discussed retrospectively through the collection of lumbar vertebra CT examination of patients with degree Ⅰ L4/5 DLS.In the basic research part,finite element analysis will be used to explore the influence of strengthening multi-fidus muscle exercise on the mechanics and displacement of lumbar spine.Purpose1.The muscle density and FJA of multifidus muscle were quantitatively determined by CT technique,and the small joint osteoarthritis was rated according to the degeneration of LFJ.In order to evaluate the correlation between LFJ degeneration and CT value of multi-fidus muscle in patients with degree Ⅰ L4/5 DLS,it provides theoretical basis for the theory of "sclero-skeletal imbalance" in bone traumatology of traditional Chinese medicine and clinicians to deeply understand the important role of multi-fidus muscle in the stability of lumbar spine.2.Based on finite element analysis,lumbar biomechanical characteristics of DLS patients were analyzed;The biomechanical changes of lumbar spine before and after multi-fidus exercise were compared by simulating multi-fidus exercise.It provides data support for the treatment idea of "treating bone from tendons" to change the pathological state of "sinew-bone imbalance" advocated by bone traumatology of traditional Chinese medicine.Methods1.Imaging data of 63 patients(17 males and 46 females)with degree I L4/5 DLS admitted to our hospital from January 2020 to December 2022 were retrospectively analyzed,and Weishaupt rating of facet joint degeneration was performed at the central level of facet joint in the slip disjoint segment.The multifidus CT and FJA were measured by two experienced radiologists.The multifidus CT value and FJA could be divided into 4groups according to Weishaupt grade of facet joint degeneration at the same level.The differences of gender,age,multifidus CT value and FJA among different facet joints Weishaupt grading groups were compared by ANOVA Analysis of Variance.Spearman method was used to evaluate the correlation between the degree of facet joint degeneration and sex,age,multifidus CT value and FJA.Pearson was used to analyze the correlation between FJA and multifidus CT value and age.After the above analysis,logistic regression analysis was performed to determine the risk factors.P < 0.05 was considered to be statistically significant.2.One patient with degree Ⅰ L4-5 DLS was selected to obtain lumbar CT,establish a three-dimensional model of DLS,and simulate the state of strengthening multi-fidus muscle exercise;The stress and displacement changes of the whole lumbar spine and various parts of the L4/5 slip disjoint segment were analyzed in the flexion and extension,left and right rotation and left and right lateral bending positions to evaluate the effect of multi-fidus muscle exercise on the DLS slip disjoint segment.Results1.Clinical study:(1)Data of 63 patients with 126 facet joints were collected;(2)After weishaupt grading of facet joints,it was found that the degree of degeneration of FJOA increased with age.In addition,with the deterioration of FJOA,the value of MFCT decreased.However,FJA decreased first and then increased.(3)Using ANOVA single factor analysis of variance,it was found that there were differences in age among groups Ⅰ and Ⅳ,but no differences among other groups(F value =3.185;P=0.026).The MF-CT values of all groups were analyzed,and significant differences were found among all groups.The comparison among groups showed that there were significant differences among all groups except for grade Ⅰ and grade Ⅱ groups(F value =37.652,P < 0.001).There was no significant difference in FJA among the other groups(F =8.055,P < 0.001),but only among the groups Ⅰ and Ⅱ,Ⅱ and Ⅳ.(4)Spearman correlation analysis showed that FJOA degeneration grade had a strong negative correlation with MF-CT value(r =-0.726,P < 0.001).There was a positive low correlation between FJOA degeneration and FJA(r = 0.324,P < 0.001).There was a weak positive correlation between FJOA degeneration grade and age(r=0.25,P < 0.005).There was no correlation between FJOA degeneration grade and sex(P = 0.158).(5)Pearson correlation analysis showed that FJA was negatively correlated with MF-CT values(r =-0.391,P < 0.001).There was no correlation between FJA and age.(6)Disordered multiclassification logistic regression analysis was used,and the results showed that MF-CT value could significantly affect the degree of FJOA degeneration in patients.In addition,the reduction of FJA is an important factor that aggravates FJOA from grade Ⅱ to GradeⅣ.2.Finite element analysis:(1)The 3D finite element model of DLS established in this study contains 1676573 elements and 2720479 nodes.(2)The displacement nephogram of the lumbar spine showed a decreasing trend from top to bottom.The maximum displacement is located at L1 and the minimum displacement is located at S1.At the same time,it can be found that after simulated MF exercise,the maximum displacement of each position showed a downward trend.(3)The stress nephogram of the lumbar spine showed that the stress of the lumbar spine was mainly concentrated in the vertebral body and isthmus.Secondly,stress distribution is more uniform after MF exercise.The further comparison of the maximum stress before and after MF exercise showed that the maximum stress of all the other positions showed a downward trend after MF exercise except for the forward flexion position.(4)The stress in the isthmus of the lumbar spine was found to be greater in the isthmus of L4 than in the isthmus of L5 except in the neutral position.By comparing the maximum stress at the isthmus of the slip disjoint section before and after MF exercise,it can be found that the maximum stress at L4 isthmus is greater than that at L5 isthmus.Secondly,after simulated MF exercise,the maximum stress value of L4 and L5 isthmus increased in neutral position,and the maximum stress value of L4 and L5 isthmus decreased in other positions compared with that before simulated MF exercise.(5)The L4/5 facet articular cartilage displacement nephogram showed that the maximum displacement before and after MF exercise was located in the anterior and upper facet joints except for the postextension position.Secondly,it was found that after multifidus muscle exercise,the displacements of neutral and forward flexion positions decreased,while the displacements of backward extension,left and right lateral flexion and left and right rotation positions increased,but the range of change was obviously small.In contrast,the displacement values of neutral and forward flexion positions decreased greatly.(6)The stress nephogram of the L4/5facet articular cartilage showed that the stress distribution was uneven before and after simulated MF exercise,and the maximum stress was mostly at the outer and lower margin of the cartilage.Secondly,the stress showed a downward trend after MF exercise.Conclusion1.Clinical studies:(1)The decline of MF-CT value runs through the lesions of DLS and FJOA,and age-related MF degeneration may be one of the initial factors leading to FJOA,and is closely related to the incidence of DLS.(2)There was a correlation between FJA and the degree of degeneration of FJOA,but the changes of FJA were pathological changes in the course of FJOA,but there was no causal relationship.In addition,in the early stage of FJOA lesions,LFJ had a partial sagittal dislocation and a partial coronal dislocation.2.Finite element analysis:(1)After the onset of DLS,the lumbar gravity line shifted forward,and the lumbar isthmus in the slide-disjointed segment and the articular cartilage of LFJ showed local high stress;(2)After simulated MF exercise,the lumbar displacement and the overall stress of the lumbar spine can be effectively reduced under various working conditions,and the abnormal stress environment of the isthmus of the slip disjunction segment and the articular cartilage of LFJ can be improved. |
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