The Significance Of The Vertebrae And Disc Changes In The Occurrence Of Degenerative Lumbar Spondylolisthesis

Objective: Along with the aging of the social population, the incidenceof degenerative lumbar spondylolisthesis (DLS) shows growth trend. Clinicalmanifestations of DLS are different degree of lower back pain, radicular pain,intermittent claudication, sensory abnormalities, motor function decline andother symptoms, making the quality of life of patients decline. Although alarge number of literatures reported the etiology of degenerative lumbarspondylolisthesis, its exact etiology remains unclear and controversial. Manyproblems have not reached consensus. DLS is a pathological process, affectedby many factors. Its causes may be: disc degeneration, facet joint morphologyabnormality, lumbosacral muscles ligaments, pelvic bony structures, changesin hormone levels, and it may also be influenced by smoking, pregnancy,diabetes, and body mass index. In the previous literatures, numerousradiologic measurements commonly by computed tomography (CT) ormagnetic resonance image (MRI) have been used to quantify the abnormalanatomic association between the lumbar and sacral spine, and the data weredetected by bivariate analysis. Unfortunately, none of these measurementshave been very reliable or readily accessible for predicting the developmentand outcome of DLS. In this study, we measured the anthropometry of thelumbosacral junction by radiograph film to explore the risk factors for DLS.Methods: Retrospectively reviewed60cases of DLS patients as the casegroup, from July2009to September2010; enrolled60cases age-andsex-matched volunteers without DLS as the control group. The case group:20males and40females, average age65.32±7.84years old,42cases with L4slipped,18cases with L5slipped. The control group:20males and40females,average age66.75±6.95years old. The inclusion criteria of the case groupwere as follows:(1)50to75years;(2) because of low back pain seeing a doctor, the initial diagnosis was DLS;(3) radiograph films were complete andclear;(4) single vertebral body forward slip;(5) did not receive furthersurgical treatment. The two groups were excluded from congenital hypoplastic,spondylolysis, pathological, traumatic, iatrogenic spondylolisthesis, andinfection, tumor, fracture, and incomplete and unclear radiograph films, andtransitional vertebrae. Measured the lumber lordosis angle(LLA), sacralhorizontal angle (SHA),lumbar index(LI), disc angle(DA), disc height(DH),the length of transverse process of L5(TPL), the width of transverseprocess of L5(TPW)of the case group in the plain films. The LI, DA, DH ofthe control group were the parameter of vertebral and disc, which werecorresponding to the slippage level of the case group. LLA: the angulationbetween the superior endplate of L1and sacrum; SHA: the angulation of thesuperior endplate of S1measured with respect to a horizontal line; DA: theangulation between the inferior endplate of the slipped level and the superiorendplate of the slipped level; LI: posterior height of the slipped vertebrae/anterior height of the slipped vertebrae; DH: the distance between themidpoint of superior endplate of the slipped level and the midpoint of theinferior endplate of the slipped level; TPL: the distance of the transverseprocess of L5from the lateral margin of the pedicle to the tip; TPW: thedistance of the perpendicular bisector of the length line. All measurementswere completed by the same imaging physician. Each measurement wascontinuously made twice, and the results were averaged. All analysis wereperformed using the SPSS13.0software. Student t test was used to examineinter-and between-group differences of parameters. Logistic regressionanalysis was used to determine the risk factors of DLS, with the entry levelα=0.05and the removal levelα=0.10. P＜0.05was considered statisticallysignificant.Results: Inter-group differences of parameter were not statisticallysignificant, so the data was merged to examine between-group. LLA, LI,DA, DH of the case group were45.83±10.42°,0.85±0.13,7.24±3.83°,9.12±2.73㎜, less than the control group,47.48±10.75°, 0.96±0.10,9.68±5.54°,10.54±2.48㎜. SHA, TPL, TPW of thecase group were28.35±11.16°,2.15±0.43㎝,1.64±0.41㎝,greater than the control group,23.16±10.68°,2.06±0.39㎝,1.57±0.32㎝. SHA, LI, DA, DH had significant differences between groups.Logistic regression analysis showed statistically significant associationsbetween DLS and LI, DA. The regression coefficients of LI and DA were－1.693,－1.406.Conclusion: DLS is significantly correlated with LI and DA. The decline oflumber index and disc angle may be the risk factors of DLS.