Etiology Of Ligamentum Flavum Hypertrophy And Surgical Treatment Of Unilateral Lumbar Spinal Stenosis With Contralateral Ligamentum Flavum Hypertrophy

BackgroundPrevious studies on etiology of the yellow ligament are mostly limited to cohort analysis of single factors such as age and gender.Few studies combine multiple factors and then analyze their respective influence effects,and no diagnosis decision route is made based on etiology;Studies on the mechanism of ligamentum flavum hypertrophy are mostly confined to the molecular,cellular or histological level,while the human spinal disease model in which the mechanical change of the ligamentum flavum can be measured is relatively rare;At the same time,the histopathological research mainly focus on the overall comparison between diverse samples,while ignoring the histological differences between disparate parts in a single one;In clinical application,regarding the surgical treatment of patients with unilateral spinal stenosis symptoms combined with hypertrophic contralateral yellow ligament,there are few special reports on the treatment of hypertrophic yellow ligament except for decompression on the symptomatic side.Object1.SPSS and R software were used to analyze the single,multiple factors and random forest of ligamentum flavum hypertrophy,and then the decision tree analysis was made.2.Establish and verify the finite element models of healthy in addition to diseased spine(containing solid ligamentum flavumt),and calculate the stress distinction of yellow ligament between disparate models and diverse parts in single model under different loading conditions.3.The ligamentum flavum histopathological research in intact and diseased models was carried out in order to understand the histological difference of the yellow ligament between the diverse models and different parts in a single model.4.Study on the postoperative effect of unilateral fenestration and decompression treatment to the unilateral spinal stenosis combined with hypertrophy of the contralateral ligamentum flavum,as well as the imaging change of ligamentum flavum.Materials and methods1.32 patients with hypertrophic ligamentum flavum and 225 patients with normal yellow ligament were included in this study.The differences of age,gender,blood sugar and other 10 indexes among them were compared and analyzed by single factor analysis,multi factor analysis and random forest analysis.Finally,the diagnosis decision route based on etiology was made according to the results;2.Five three-dimensional finite element L4/5 models respectively represent intact,mild and severe disc degeneration and degenerative spondylolisthesis were established and verified.By measuring the surface stress of the ligamentum flavum in different models,we could find out the stress distinction between healthy and pathological model,as well as different parts in intact model.3.The HE staining,Masson staining and TGF-β1 immunohistochemical staining of ligamentum flavum in healthy and pathological models were observed under microscope.According to sairyo and other scoring standards,the histological comparison between groups and within groups was carried out.4.Cases of unilateral and bilateral laminectomy and interbody fusion were included as observation and control group one,The treatment of unilateral spinal stenosis and hypertrophy of the contralateral ligamentum flavum were compared by postoperative efficacy,operation time,bleeding volume and other indicators.In addition,the patients with normal thickness of contralateral ligament were treated as control group two,observed the changes of the thickness of the ligamentum flavum before and after the operation,and then analyzed the etiology of hypertrophic disease once more.Conclusion:1.Lumbar spondylolisthesis and disc degeneration were the most prominent risk factors for the hypertrophy of ligamentum flavum;2.The stress of the ligamentum flavum in the degenerative,normal and spondylolisthesis models was generally increasing,and the ligamentum flavum stress difference between the dorsal and ventral sides and between the lamina and the lateral parts was also obvious;3.The histopathological score of the ligamentum flavum in normal,degenerative and spondylolisthesis models increased,and there were also ligamentum flavum histological differences between the dorsal and ventral sides as well as the lamina and the lateral parts;4.For patients with lumbar unilateral stenosis and hypertrophy of the contralateral ligamentum flavum,unilateral fenestration and interbody fusion could also achieve agreeable effect compared to bilateral decompression;the reasons of ligamentum flavum hypertrophy in the spine might be due to the reduction of intervertebral height and the increasing stress.