| Background:Lumbar degenerative kyphosis(LDK)is a common problem in the elderly population,especially in the Asian population.It is thought to be a sagittal imbalance caused by significant loss of lumbar lordosis or lumbar kyphosis.This disease brings a huge burden to society,economy and family.Dynamic sagittal imbalance(DSI)refers to the fact that a good sagittal balance can be maintained in the resting position,and obvious body leaning or hunchback appears after a period of walks or activity.Bae J described the dynamic sagittal imbalance in patients with degenerative flat back syndrome for the first time.Zhou et al.recently proposed a new classification of DSI and its quantitative diagnostic criteria.The quantitative diagnostic criteria was pre-walk SVA<40 mm and post-walk SVA-pre-walk SVA≥20 mm after 10-min walk(ΔSVA)≥20mm.However,in clinical practice,we found that some LDK patients could maintain long-term sagittal balance during walking or activity(the "compensated" group),while some LDK patients showed significant forward leaning or hunchback after walking or activity(the"decompensated" group).Previous studies have used 3D gait analysis and full spine x-rays before and after walking to determine the detailed changes in the sagittal parameters of the spine in such patients.However,as far as we know,the difference in paravertebral muscle degeneration between the "compensation" group and the"decompensation" group has not been studied.Objective:To explore the degeneration of the lumbar paravertebral muscles in patients with degenerative lumbar kyphosis accompanied by dynamic imbalance,and to explore the correlation between the degree of paravertebral muscle degeneration and the severity of dynamic imbalance.Explain the detailed pathogenesis of patients with degenerative lumbar kyphosis accompanied by dynamic imbalance,and help clinicians better understand the importance of paravertebral muscles in maintaining spine balance,so as to make early diagnosis and effective intervention for such patients.Method:From October 2018 to May 2020,a total of 132 LDK patients who attended the spinal surgery department of Shandong Provincial Hospital were recruited to participate in this study.According to the SVA difference of the lateral view of the whole spine before and after the 10-minute walk test,132 patients with LDK were divided into DSI group(31 cases)and control group(42 cases).Each patient underwent magnetic resonance imaging of the lumbar spine.Image J software was used to quantitatively determine the relative total cross-sectional area(RTCSA),fatty infiltration area(FIA)and relative functional cross-sectional area(RFCSA)of the multifidus(MF)and erector spinae(ES)at the L2 and L4 levels.Use SPSS 21.0 for relevant statistical analysis.Variables between the two groups were compared by independent sample t test.P value less than 0.05 is considered statistically significant.Results:There was no statistical difference in the RTCSA between L2 level(MF,p=0.090;ES,p=0.366)and L4 level(MF,p=0.663;ES,p=0.0.304).In the comparison of muscle parameters between the two groups,there were statistically significant differences in FIA at the L2 level(MF,p=0.001;ES,p=0.023)and L4 level(MF,p=0.001;ES,p=0.001).There was a statistical difference in the RFCSA between the L2 level(MF,p=0.045;ES,p=0.016)and the L4 level(MF,p=0.001;ES,p=0.002).We found no correlation between the severity of lumbar paravertebral muscle degeneration(both ES and MF)at the L2 and L4 levels and the clinical severity of dynamic imbalance(ΔSVA).Conclusions:Compared with the control group,the degeneration of the lumbar paravertebral muscles in DSI patients was more serious.However,the severity of DSI symptoms is not significantly correlated with the degeneration of the lumbar paravertebral muscles.These results help spine surgeons better understand the importance of paravertebral muscles in maintaining spine sagittal balance. |
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