| BackgroudDegenerative lumbar spondylolisthesis (DLS) is one of the common diseases in clinical orthopaedics leading to lumbocrural pain of the middle-aged and elderly. Manipulation of Traditional Chinese medicine (TCM) is an important mean to treat DLS by non-operative therapy, and sitting lumbar rotation manipulation, being widely applied in clinic, has been accepted by both of doctors and patients because of its positive effects. Becides, functional training can consolidate curative effect of manipulation, so synergy of manipulation and functional training has significant effect on treating DLS.However, the mechanism of sitting lumbar rotation manipulation being unknown, the safety and rationality also questioned, these problems have greatly restricted the development of the clinical application of this manipulation. Using finite element method to analyze manipulation has irreplaceable advantages compared with other traditional biomechanical study. In recent years, some researchers make use of finite element method to analyze the sitting lumbar rotation manipulation that provides a new pathway to study the mechanism and safety of this manipulation. After literature review, it is found that previous studies have analyzed the stress and displacement distribution in lumbar segment of normal and degenerated intervertebral disc during the manipulation by finite element method, but the stress and displacement distribution in lumbar segment of degenerative spondylolisthesis are still short of reliable analysis. In addition, it is also lack of comparative study on the mechanics distribution between lumbar segment of normal and degenerative spondylolisthesis.Objective1To evaluate clinical effects of sitting lumbar rotation manipulation with lumbar rehabilitation exercise in treating DLS. 2To comparatively study the stress distribution between degenerative lumbar spondylolisthesis segment and normal lumbar segment under body-weight loading in neutral position, so as to explore the changes of stress distribution in lumbar segment after degenerative spondylolisthesis.3To analyze the stress and displacement distribution in degenerative lumbar spondylolisthesis segment under sitting lumbar rotation manipulation, and compared with normal lumbar segment, so as to explore mechanism, safety and rationality of the manipulation in treating DLS.Method1Clinical research120cases of DLS were randomly divided into trial group and control group, with60cases in each group. Trial group using sitting lumbar rotation manipulation with lumbar rehabilitation exercise, while control group using lumbar traction with lumbar bracing. The treatment of2groups for3weeks, trial group once every other day,3times a week, total9times, while control group once a day,5times a week, total15times. JO A and VAS scores were recorded in13time points that including the first day of access to the study,1,3,5,8,10,12,15,17,19after that day, and1month,3months,6months follow-up. Total curative effect was evaluated by JOA curative effect evaluation standard. The data were analyzed by use of SPSS13.0statistical software. Statistical description of enumeration data and ranked data adopted number of cases. Enumeration data used chi-square test, while ranked data used Wilcoxon rank sum test. Statistical description of measurement data adopted mean±standard deviation. Intra-group comparison used pared-samples T test, while comparison of difference between groups used Wilcoxon rank sum test. P<0.05was considered to be a statistics significance.2Experimental research2.1Comparative study on the stress distribution between degenerative lumbar spondylolisthesis segment and normal lumbar segment under body-weight loading in neutral positionThe L4-5CT images of a normal volunteer and a DLS patient were collected, after that using Mimics10.01and Abaqus6.10software established finite element models of normal L4-5segment and degenerative spondylolisthesis L4-5segment. Lower surface of L5was constrainted. Axial compression load of450N was loaded on upper surface of L4, which simulated the load of lumbar vertebra under body-weight loading in neutral position. Two finite element models were loaded as the above conditions, then the stress distribution of different structures in the models were analyzed by Abaqus6.10software.2.2Finite element analysis of the stress and displacement distribution in degenerative lumbar spondylolisthesis segment under sitting lumbar rotation manipulationThe L4-5CT images of a normal volunteer and a DLS patient were collected, after that using Mimics10.01and Abaqus6.10software established finite element models of normal L4-5segment and degenerative spondylolisthesis L4-5segment. The direction of sitting lumbar rotation manipulation was towards right, and load conditions of the models as follow,①lower surface of L5was constrainted;②vertical compression load of450N was loaded on upper surface of L4;③flexion6°, lateral bending toward right6°, rotation toward right2°;④loading toward left-anterior of50N was loaded on spinous process of L4;⑤clockwise moment of15Nm was loaded on the upper surface of L4;⑥instant time was0.25s. Two finite element models were loaded as the above conditions, then the stress and displacement distribution of different structures in the models were analyzed by Abaqus6.10software.Result1Clinical research1.1Comparison between2groups in total curative effectsAt the end of treatment,1month,3months,6months follow-up, total effective rate of trial group, respectively, was96.67%,96.67%,96.67%,95.00%, while that of control group was90.00%,83.33%,71.67%,63.33%, respectively, cured and markedly effective rate of trial group, respectively, was73.33%,68.33%,65.00%,61.67%, while that of control group was58.33%,45.00%,38.33%,20.00%, respectively. There were statistical significances in total curative effects between2gtoups (P<0.01).1.2Intra-group comparison of JOA scores between the first access and other each observation point in2groupsIn trial group, JOA scores of every observation point from1day after the first access to the end of follow-up were higher than those of the first access (p<0.01). In control group, there was no significant difference between JOA scores of the first access and1day after it (p>0.05), while JOA scores of every observation point from3day after the first access to the end of follow-up were higher than those of the first access (p<0.05or p<0.01).1.3Comparison between2groups in difference value of JOA scores the first access and other each observation pointIn trial group, difference values of JOA scores of every observation point from1day after the first access to the end of follow-up and the first access were higher than those in control group (p<0.05or P<0.01).1.4Intra-group comparison of VAS scores between the first access and other each observation point in2groupsIn trial group, VAS scores of every observation point from1day after the first access to the end of follow-up were lower than those of the first access (p<0.05or p<0.01). In control group, there was no significant difference between JOA scores of the first access and1day,3day after it (p>0.05), while VAS scores of every observation point from5day after the first access to the end of follow-up were lower than those of the first access (p<0.01).1.5Comparison between2groups in difference value of VAS scores the first access and other each observation pointIn trial group, difference values of VAS scores of every observation point from1day after the first access to the end of follow-up and the first access were higher than those in control group (p<0.05or P<0.01).2Experimental research2.1Comparative study on the stress distribution between degenerative lumbar spondylolisthesis segment and normal lumbar segment under body-weight loading in neutral position(1) Cortical bone of L4vertebral bodyIn normal lumbar segment (NLS), stress was relatively concentrated in an annulus region of central position on both sides. Compared with NLS, in degenerative lumbar spondylolisthesis segment (DLSS), stress was decreased in anterior side, while stress distribution of other positions was no obvious difference.(2) L4posterior structureIn NLS, stress was concentrated in vertebral isthmic, articular surface of inferior articular process, and vertebral pedicle. Compared with NLS, in DLSS, stress concentration region was significantly increased. Becides vertebral isthmic, articular surface of inferior articular process, and vertebral pedicle showing stress concentration, stress of vertebral lamina of medial side of inferior articular process was also concentrated, and stress concentration region in articular surface of inferior articular process was enlarged.(3) Intervertebral discIn NLS, stress was mainly distributed in annulus fibrosus, while stress of the nucleus pulposus is relatively small. Compared with NLS, in DLSS, stress of annulus fibrosus was more concentrated.(4) Cortical bone of L5vertebral bodyIn NLS, stress was was relatively homogeneous and didn’t show obvious stress concentration. Compared with NLS, in DLSS, stress of position close to vertebral pedicle was greatly concentrated.(5) L5posterior structureIn NLS, articular surface of superior articular process showed stress concentration of small area, while stress of other position was relatively homogeneous. Compared with NLS, in DLSS, stress concentration region in articular surface of superior articular process was enlarged, while stress of vertebral pedicle, vertebral isthmic and lateral-bottom side of superior articular process was highly concentrated.2.2Finite element analysis of the stress and displacement distribution in degenerative lumbar spondylolisthesis segment under sitting lumbar rotation manipulation2.2.1Stress distribution(1) Cortical bone of L4vertebral bodyIn NLS, stress was concentrated in left-anterior and right-lateral side of vertebral body. Compared with NLS, in DLSS, stress concentration region moved back:stress concentration region of left-anterior side of vertebral body was decreased, while left-lateral side of vertebral body and position close to vertebral pedicle showed stress concentration.(2) L4posterior structureIn NLS, stress concentration in ventral side of left vertebral pedicle and left articular surface of inferior articular process was the most obvious, while stress of dorsal side of right vertebral isthmic and medial side of left inferior articular process was relatively concentrated. Compared with NLS, in DLSS, stress of ventral side of left vertebral isthmic, dorsal side of right vertebral isthmic and left articular surface of inferior articular process was more concentrated, while stress concentration region of left articular surface of inferior articular process was significantly enlarged. Vertebral pedicle showed stress concentration.(3) Intervertebral discIn NLS, stress was mainly concentrated in right-posterior annulus fibrosus and distributed in form of ring from right side to left side of annulus fibrosus showing diminishing trend. Compared with NLS, in DLSS, stress of annulus fibrosus was more concentrated, whose distribution area changed:stress of left-posterior side and left-posterior-lateral side of annulus fibrosus was the most concentrated, while stress of anterior side, right-lateral side, and right-posterior side was relatively concentrated.(4) Cortical bone of L5vertebral bodyIn NLS, stress of position close to left vertebral pedicle was the most concentrated, while stress of anterior side, left-lateral side, and position close to right vertebral pedicle was relatively concentrated. Compared with NLS, in DLSS, stress concentration region in anterior side was decreased, while stress distribution of other positions was no obvious difference.(5) L5posterior structureIn NLS, articular surface and lateral-bottom side of left superior articular process showed stress concentration. Compared with NLS, in DLSS, stress of articular surface and lateral-bottom side of left superior articular process was more concentrated. Left vertebral isthmic and vertebral pedicle showed stress concentration.2.2.2Displacement distribution(1) Displacement distribution of L4In NLS, the maximal displacement was located in spinous process, while the minimum displacement was located in subcircular area nearby right-posterior-superior part of vertebral body and vertebral pedicle. In DLSS, the maximal displacement was also located in spinous process, while the minimum displacement was located in arc area from right-posterior-inferior part of vertebral body to inferior part of right vertebral pedicle. Compared displacement of posterior structure in DLSS with that in NLS, the similarities were that displacement of spinous process was the maximal, and displacement of left structure was greater than that of right structure; the differences were that in DLSS, displacement of left superior articular process, inferior articular process, and transverse process was larger, while that of right transverse process was smaller.(2) The changes of intervertebral foramenIn both NLS and DLSS, left intervertebral foramen was obviously enlarged, while the enlargement of right intervertebral foramen wasn’t evident.(3) Displacement distribution of intervertebral discIn NLS, displacement in oval area of left-posterior side was the smallest, from where displacement was increasing to the surrounding. Displacement from right-lateral side to left-anterior-lateral side was the largest, while displacement of left-lateral side and posterior side was relatively large. In DLSS, displacement of right-posterior-lateral side was the smallest, from where displacement was increasing to the surrounding. Displacement from right-anterior-lateral side was the largest, while displacement of left-posterior side was relatively large. In NLS, displacement of right-posterior side was backward, while that of right-posterior side was up-outward. In DLSS, displacement of right-posterior side was very small, while displacement of left-posterior side was up-forward.Conclusion1Clinical research(1) At the end of treatment and during the follow-up period, total curative effects of trial group (sitting lumbar rotation manipulation with lumbar rehabilitation exercise) in treating DLS was better than control group (lumbar traction with lumbar bracing), and during the follow-up period, total curative effects of trial group was more lasting.(2) Dring both the treatment and follow-up periods, either trial group or control group could efficiently improve symptoms, signs and pain of DLS, and the onset time of trial group was earlier.(3) Dring both the treatment and follow-up periods, the improvement of symptoms, signs and pain in trial group was more significant than that in control group.To sum up, in either short term or long term, sitting lumbar rotation manipulation with lumbar rehabilitation exercise in treating DLS, having the advantages of quick and long-term results, has obtained the satisfactory clinical effects.2Experimental research(1) Under body-weight loading in neutral position, compared with normal lumbar segment, the stress distribution of degenerative lumbar spondylolisthesis segment has greatly changed, which can cause that facet joint, vertebral isthmic and vertebral pedicle are more likely to be injuried acutely or chronically.(2) Under sitting lumbar rotation manipulation, compared with normal lumbar segment, stress of facet joint, vertebral isthmic and vertebral pedicle is more concentrated or stress concentration region of the structures is enlarged, and stress of annulus fibrosus is also more concentrated, which indicate that the manipulative force on DLS should be more light, so as not to the above stuctures.(3) As sitting lumbar rotation manipulation acting on degenerative lumbar spondylolisthesis segment, posterior side of intervertebral disc and facet joint show the displacement, meanwhile intervertebral foramen is enlarged, which should be concerned in the mechanism of this manipulation.(4) As sitting lumbar rotation manipulation acting on degenerative lumbar spondylolisthesis segment, it is feasible to rotate lumbar toward both sides under suitable force. However, it is more reasonable to rotate lumbar toward the opposite side of symptom.Innovation point1According to the L4-5CT images of a normal volunteer and a DLS patient, two finite element models of normal lumbar segment and degenerative lumbar spondylolisthesis segment, then to comparative study on the mechanical distribution between them.2To analyze the stress and displacement distribution in degenerative lumbar spondylolisthesis segment under sitting lumbar rotation manipulation by finite element method, so as to explore mechanism, safety and rationality of the manipulation in treating DLS. |
