| BackgroundLumbar spondylolisthesis is a common clinical disease of spine and is classified as degenerative,isthmic,dysplastic,traumatic or pathological,the first two being the most common.Spinal instability is defined by Pope and Panjabi as the displacement of the corresponding vertebral body due to the loss of stiffness or toughness of the constraint structures,including the intervertebral discs and articular processes,etc.The spine is a three-dimensional structure,if the combined forces from different directions and magnitudes do not reach a stable state,will cause a change in the position or orientation of the vertebral body.The radiographic features and risk factors for degenerative lumbar spondylolisthesis have been investigated in the past.Reported risk factors include female gender,lumbar degeneration(higher disc Pfirrmann grade,posterior sacral deformity and articular synostosis),sagittal alignment of the articular surfaces,lumbar lordosis,lumbar index,shorter transverse processes,decreased anterior disc height and atrophy of the multifidus muscle.For risk factors for isthmic spondylolisthesis have been reported such as disc herniation or altered spinal pelvic morphology,relatively thin iliolumbar ligaments,elevated stress on structures around the growth plate during childhood leading to epiphyseal separation,epiphyseal ring rupture and slippage of the growth plate.There is a basic consensus that loss of disc height is considered the initiating factor in degenerative lumbar spondylolisthesis.B.VERNON-ROBERTS and C.J.PIRIE,through the dissection and analysis of a large number of specimens,concluded that degenerative changes of spine are initially caused by ageing,degeneration or even prolapse of the normal discs causing structural disorganisation,followed by local or global thinning of the discs,leading to the forward tilt of the superior vertebral body around the axis of the articular eminence joint,resulting in vertebral instability,causing a series of subsequent changes such as joint degeneration and osteophytes.It has been found that intervertebral mobility is more pronounced when the disc height is greater or the degeneration is less severe,and that the disc height of the diseased segment decreases in patients with lumbar spondylolisthesis compared to the norm.However,the initial disc height prior to lesion has not been studied.Although the radiographic changes in the two types of lumbar spondylolisthesis have been explored extensively both nationally and internationally,most of these studies have examined only a single parameter or a single level of the lesioned segment,and none have compared these two most common types of lumbar spondylolisthesis in detail.In contrast,lumbar spondylolisthesis is supposed to be the result of a multi-structural,multifactorial interaction,so it is more reasonable to explore the multiple factors that are at risk for its development.Many scholars have made similar findings that disc degeneration underlies degenerative lumbar spondylolisthesis,but few relevant studies have specifically examined the correlation between disc height and changes in other tissues.ObjectivesTo compare the imaging parameters of degenerative spondylolisthesis and isthmic spondylolisthesis with the normal population,analyze the radiological risk factors and Cutoff value of two types of lumbar spondylolisthesis,and the correlation between the disc height and other parameters of degenerative spondylolisthesis.Study methodsA total of 75 patients with L4 grade 1 degenerative spondylolisthesis(degenerative group)who received treatment in Qilu Hospital of Shandong University from October 2017 to October 2022 were retrospectively analyzed,including 26 males and 49 females,with an average age of(59.1±6.1)years.33 patients with isthmic spondylolisthesis(isthmic group),including 14 males and 19 females,with an average age of(56.9±5.1)years.A total of 50 subjects,23 males and 27 females,aged(58.4±5.4)years,were collected as the control group.L1-4 disc height index,facet joint angle of L4/5 lesion segment and paravertebral muscle(multifidus,erector spine and psoas major)relative cross-sectional area(RCSA)were measured and compared between the three groups.The lumbar pelvic sagittal parameters were measured in the degenerative group and isthmic group,and compared between the two groups.The L4/5 initial disc height index was calculated from L3/4 disc height index of the degenerative group and isthmic group,and compared with the control group.Binary Logistic regression analysis was used to analyze the imaging risk factors of two types of lumbar spondylolisthesis.Receiver operating characteristic curve and Youden index were used to calculate the Cutoff value of each risk factor.Pearson correlation analysis was used to calculate the correlation between the L4/5 initial disc height index and other parameters for two types of lumbar spondylolisthesis.In the degenerative spondylolisthesis group,Pearson correlation analysis was used to analyze the correlation between the L4/5 disc height index and other parameters.ResultsThe L4/5 disc height index of the degenerative group and isthmic group was lower than that of the control group(P<0.05),but the L1-L4 segment was higher than that of the control group(P<0.05).The ratio of L4/5 to L3/4 disc height index was lower than that of the control group(P<0.05),and the L4/5 initial disc height index(0.52±0.12)of the degenerative group and isthmic group(0.54±0.15)was significantly higher than that of the control group(0.41±0.07)(P<0.05).The L4/5 facet joint angle of degenerative spondylolisthesis group was higher than that of control group(P<0.05).The RCSA of the three paraspinal muscles in the degenerative spondylolisthesis group was smaller than that in the control group(P<0.05).The RCSA of multifidus muscle and psoas major muscle in isthmus group was smaller than that in control group(P<0.05).The increased L4/5 initial disc height index(OR=1.35,95%CI:1.12～1.63,P=0.002),facet joint angle(OR=1.68,95%CI:1.26～2.27,P=0.001),and decreased RCSA of total paraspinal muscle(OR=0.60,95%CI:0.44～0.82,P=0.001)were risk factors for degenerative lumbar spondylolisthesis.The Cutoff value of L4/5 initial disc height index,facet joint angle and relative cross-sectional area of total paraspinal muscle as risk factors were 0.50、51.33°、1.98,respectively.The increased L4/5 initial disc height index(OR=1.12,95%CI:1.05～1.19,P=0.001),and decreased RCSA of total paraspinal muscle(OR=0.78,95%CI:0.67～0.92,P=0.003)were risk factors for isthmic spondylolisthesis.The Cutoff value of L4/5 initial disc height index and relative cross-sectional area of total paraspinal muscle as risk factors were 0.50、2.24,respectively.There was a significant positive correlation between L4/5 initial disc height index and lumbar lordosis(r=0.35,P<0.05)in the degenerative group.There was a significant positive correlation between L4/5 disc height index and L2/3(r=0.53,P<0.05),L3/4(r=0.58,P<0.05),L5/S1(r=0.51,P<0.05)in the degenerative spondylolisthesis group.There was a significant positive correlation with the RCSA of multifidus muscle(r=0.34,P<0.05),psoas major muscle(r=0.28,P<0.05)and total paraspinal muscles(r=0.31,P<0.05).ConclusionCompared with normal people of the same age,larger initial lumbar intervertebral height,facet joint angle and paravertebral muscle atrophy may be risk factors for lumbar degenerative spondylolisthesis.Larger initial lumbar intervertebral height and paravertebral muscle atrophy are risk factors for isthmic spondylolisthesis.Compared with degenerative lumbar spondylolisthesis,isthmic spondylolisthesis have lower intervertebral height,facet joint angle in the diseased segment,and more pronounced sagittal imbalance.In patients with degenerative lumbar spondylolisthesis,the smaller the lesion intervertebral height,the smaller the surrounding intervertebral space,and the more obvious paraspinal atrophy. |
PDF Full Text Request