Risk Factors In Patients With Degenerative Lumbar Spondylolisthesis

【Background】Degenerative lumar spondylolisthesis(DLS) is the slippage of one vertebra relative to the adjacent vertebrae due to spinal degenerative changes.The main manifestations are mechanical low back pain,the radicular pain with numbness, paraesthesia,and sensory or motor deficit,and neurogenic claudication.Unlike isthmic spondylolisthesis,degenerative spondylolisthesis is not identifiable defect in the posterior neural arch.It has traditionally been considered as one of the major causes of low back and leg pain among the elderly.When symptomatic,the resultant neurogenic claudication often leads to a diminished quality of life.Spondylolisthesis in the absence of a pars defect was first described as early as in 1930 by Junghanns.The term "degenerative spondylolisthesis" was coined by Newman in 1955,who noted that slippage of the vertebrae with an intact neural arch was the result of degenerative arthritis of the lumbar facet joints.Previous studies showed that an overall incidence of degenerative spondylolisthesis was 8.7%.This condition typically presents in individuals older than age 50 years and is four times more common in females than in males.Predominantly affects the L4-L5 level and much less frequently L5-S1 or L3-L4 levels,and the degree of slip rarely exceeds 30%.Degenerative spondylolisthesis(DS) was first described by Junghanns in 1930, many studies have been undertaken in an attempt to explore its etiology and pathomechanisms,but so far this are still controversial.It has been thought that excessive mechanical stresses at the L4-5 level may cause degenerative changes in the disc and lumbar facet joints,and with disc and facet joints degeneration,which eventally lead to segmental instability in the sagittal plane.Degenerative changes causing wear and anterior deformation of the articular processes,and the facet joints orientation are gradually more sagittally and horizontally,eventually allow the 4th lumbar vertebra to slip forward.But the pars interarticularis of a vertebra is not defect, so this type of spondylolisthesis is also called "pseudo-spondylolisthesis".Pregnancy, generalized joint laxity,and oophorectomy are thought to be predisposing factors of this condition and its predominance in females.Sagittal orientation of the facet joints have been described as predisposing factors.However,it is unclear whether the facet joints orientation is a primary cause or a secondary effect,and this hypothesis does not explain the mechanism of anterior vertebral slip in patients with a coronal orientation of the facet joints.It may be additional predisposing factors involved in the process of vertebral slipping.Degenerative lumbar spondylolisthesis is not an isolated disease,which is an integral part of the spinal degenerative changes and often accompanied by lumbar hyperosteogeny,lumbar disc bulging or herniation,and facet joint's disease at a latter stage.Spondylolisthesis often lead to spinal stenosis,lateral recess stenosis,the ligamentum flavum hypertrophy,and a series of pathological changes,which increase the symptoms and affect the patients quality of life seriously. Therefore,early prevention,diagnosis and to take reasonable measures to this condition may alleviate patient's pain and improve the quality of life,and it's important clinical significance,many studies have been taken to explore the etiology and pathogenesis of Degenerative Lumbar Spondylolisthesis in the past years,but these studies often be carried out from One aspect of this field.Because the causes and pathogenesis of degenerative lumbar spondylolisthesis are extremely complex and are the result of the interaction of various factors,the study of single factors maybe exaggerate the role for some certain,and the credibility of the conclusion is not enough.In current study,a retrospective case-control study,using single-factor screening,multi-factor logistic regression analysis to explore the risk factors of degenerative lumbar spondylolisthesis and to provide a theoretical basis for prevention and treatment of degenerative lumbar spondylolisthesis,and to lay the foundation for further study.【Objective】1.To find out the risk factors which contribute to degenerative lumbar spondylolisthesis.2.To explore the correlation between age and orientation of the lumbar facet joints.3.To provide a theoretical basis for prevention and treatment of degenerative lumbar spondylolisthesis,and to lay the foundation for further research.【Methods】1.From March 2004 to March 2009,200 cases of degenerative lumbar spondylolisthesis(DLS) in our hospital were review.200 cases without spondylolisthesis were studied as control group.Age,gender,body height,weight, body mass indes(BMI),history of diabetes,imaging indicators,including the facet joints orientation,the severity of degeneration of facet joints,the pedicle-facet angle,the pelvic incidence,pelvic tilt,sacral slope,disc height ratio, lumbar intervertebral disc angle,lumbar lordosis,lumbosacral angle and intercrestal line using single-factor screening and multi-factor Logistic regression analysis.2.300 spinal disease-free people coming for periodic physical examination during May 2007 and May 2008 in our hospital accepted lumbar CT scanning and were randomly selected.All the subjects were divided into 6 groups based on age (GroupⅠ:less than 30 years of age,GroupⅡ:31～40 years,GroupⅢ:41～50 years,GroupⅣ:51～60 years,GroupⅤ:61～70 years,and GroupⅥ:greater than 70 years of age).CT scans of the lumbar spine were stored in digitized form for measurement and analysis.The orientation of the lumbar facet joints at the L4-5 was measured on axial CT scans,and the intersection angle of the midsagittal line of vertebra to the facet line represent the orientation of the facet joint. 3.Statistical analysis:Statistical analysis was performed using SPSS13.0 statistical software.Measurement data using(?)±SD.Comparison between two groups,if they were measurement data,unpaired t test would be used,if they were enumeration data or ranked data,we would apply Mann-Whitney.Comparison between the groups and multiple comparisons were conducted using variance analysis and LSD respectively.The correlation analysis was performed with Pearson method.All the independent variables were analyzed with the single factor analysis and multifactor logistic regression analysis.The criterion for statistical significance was P＜0.05.【Results】1.The general clinical data and imaging measurement indicators of DLS and control groups.Total cases-400,there were 200 cases in DLS group,200 cases in control group.Age,DLS group(61.11±10.25) years old(37～82ys),control group (59.82±10.02)years old(33～80ys).(P=0.206,t=1.268 ).Gender,DLS group,male 37 cases,female 163 cases,control group,male 41 cases,female 159 cases.(P=0.705,χ~2=0.255).History of diabetes,DLS group 51 cases,control group 15 cases.(P=0.000,χ~2=23.517).Body height,DLS group(159.24±6.29)cm,control group(160.31±5.88)cm. (P=0.080,t=1.758)Weight,DLS group(66.99±11.09)Kg,control group(52.76±7.03)Kg.(P=0.000, t=15.335).Body mass index(BMI),DLS group(26.25±2.75)kg/m2,control group (20.49±2.19)kg/m2.(P=0.000,t:23.155).Facet joints orientation(FJO),DLS group 33.53°±8.75°,control group 47.74°±5.52°.(P=0.000,t=19.417).Pedicle-facet angle(PFA),DLS group 115.52°±55.28°,control group 102.51°±4.54°.(P=0.000,t=26.428)Pelvic incidence(PI),DLS group 58.98°±7.39°,control group 51.32°±7.60°. (P=0.000,t=10.215).Pelvic tilt(PT),DLS group 22.06°±7.90°,control group 11.21°±2.75°. (P=0.000,t=18.347).Sacral slope(SS),DLS group 36.92°±6.03°,control group 40.12°±8.36°. (P=0.000,t=4.384).Lumbar lordosis(LL),DLS group 27.90°±6.40°,control group 40.58°±7.63°. (P=0.000,t=18.008).Lumbosacral angle(LSA),DLS group 39.63°±3.46°,control group 36.21°±2.38°. (P=0.000,t=11.529).Disc height ratio(DHR),DLS group 0.23°±0.05°,control group 0.27°±0.48°. (P=0.000,t=8.068).Lumbar intervertebral disc angle(LIDA),DLS group 4.13°±2.51°,control group 12.38°±4.08°.(P=0.000,t=24.350).The severity of degeneration of facet joints,DLS group,Mean rank 266.26, control group,Mean rank 134.75.(P=0.000,Z=11.898).Intercrestal line(ICL),DLS group,Mean rank 218.18,control group,Mean rank 182.82.(P=0.000,Z=3.612).The degree of spondylolisthesis of DLS Group was 8%～37%,with an average 18.81%±6.29%.2.Result of binary logistic regression.DLS--YPFA--X1 FJO--X2BMI--X3PI--X4Equation,Y=-606.689+5.504X1-2.397X2+9.098X3-11.300X4(R=0.75,P＜0.001).Analysis of this model suggests that PFA,FJO,BMI and PI exert significant influences to DLS.The greater of P-F angle,BMI and PI,and the smaller the angle between the sagittal plane of vertebral body and facet joint line are more susceptible to the DLS.【Conclusions】1.In recent study,the history of diabetes,weight,body mass index,the facet joints orientation,the pedicle-facet angle,pelvic incidence,pelvic tilt,sacral slope, lumbar lordosis,disc height ratio,lumbar intervertebral disc angle,the severity of degeneration of facet joints as well as the intercrest line comparison between DLS group and the control group were significantly different.2.The binary logistic regression model suggested that the increase of P-F angle, BMI and PI were risk factors of DLS.3.Our study found that with advancing age,the coronal orientation of the lumbar facet joints gradually decreased.The coronal orientation of the L4-5 facet joints was negatively correlated to age.