Clinical Outcomes And Radiologic Results Of OLIF Treating The Degenerative Lumbar Central Canal Stenosis

Background:Oblique Lateral Interbody Fusion(OLIF)is one kind of lateral interbody fusion which has been used in clinic in recent years.Previous studies have shown that the indirect decompression effect of lateral fusion for degenerative lumbar central spinal stenosis is inconsistent,and its effect for severe central spinal stenosis is still unclear.Objective:1.To study the radiologic results of patients with degenerative lumbar spinal stenosis treated by indirect decompression of Oblique Lateral Lumbar Interbody Fusion(OLIF),and to explore the related factors affecting the extension ratio of central spinal canal and its relation with symptom relieving.2.To analyze the radiologic results and clinical outcomes of OLIF in mild,moderate and severe lumbar spinal stenosis and compare the radiologic results and clinical outcomes of OLIF treating different degree of lumbar stenosis.As to preliminarily study whether severe spinal stenosis is an indication of OLIF.Methods:1.This is a retrospective study.The data of patients with degenerative lumbar spinal stenosis treated by OLIF from April 2016 to February 2018 were collected.The clinical outcomes was evaluated by visual analogue scale(VAS)and Oswestry disability index(ODI).The radiologic parameters were measured before and after the operation,such as the disc height,the foraminal height,the segmental angle,the lumbar lordotic angel,the area of the intervertebral foramen on both sides,the cross-sectional area of canal,the anteroposterior diameter of canal,the cross-sectional area of the ligamenta flavum,the position of the cage,and the angle of the cage.The changes of parameters before and after operation were compared.The correlation between the radiologic parameters,clinical outcomes and the cross-sectional area of canal was studied by linear regression analysis.2.The patients were divided into three groups:group A included mild stenosis,group B included moderate stenosis,group C included severe stenosis.The changes of radiologic and clinical results before and post operation in three groups were analyzed.Results:1.61 patients were included in this study.The average height of intervertebral space increased by 0.77 cm,the average height of intervertebral foramen increased 38.43 mm~2,the anteroposterior diameter of the spinal canal increased 4.61 mm,the cross-sectional area of the ligamentum flavum decreased 33.78 mm~2,the area of the right intervertebral foramen increased 34.32 mm~2,the area of the left intervertebral foramen increased 35.63 mm~2.The ratio of patients with cages located at the middle thirdThe improvement rates of VAS and ODI were 51%and 66%,respectively.Linear regression analysis showed that the extension ratio of the cross-sectional area of canal was only negatively correlated with the cross-sectional area of the spinal canal before operation and had statistical significance,but had no significant relationship with the change of clinical outcome parameters.2.There were 21 patients with mild stenosis(group A).The improvement rates of VAS and ODI were 63.0%and 73.1%,respectively.The extension ratio of cross-sectional area of spinal canal was 26%.One patient recurred due to the collapse of the fusion cage,which was relieved by decompression of the posterior minimal invasive surgery.There were 29 patients with moderate stenosis(group B).The improvement rates of VAS and ODI were 62.8%and 74.5%,respectively.The extension ratio of cross-sectional area of spinal canal was 44%.All patients did not receive direct decompression.Severe stenosis(Group C)included 11 patients.The improvement rate of VAS and ODI was 62.9%and 77.5%,respectively.The extension rate of cross-sectional area of spinal canal was 53%.One patient was not satisfied with the symptom relief after OLIF.There were no significant differences in terms of gender,age,BMI,intraoperative hemorrhage and average hospital stay among the three groups.The cross-sectional area and anterior and posterior diameter of spinal canal in group A were larger than those in group B and larger than those in group C.The order of the extension ratio of cross-sectional area of spinal canal and the enlargement range of anteroposterior diameter of spinal canal from large to small is Group C,group B and group A.The preoperative VAS score and ODI in group C were higher than that in group A and B,but the differences did not reach statistical significance(p>0.05).On 24 months follow-up,the improvement rate of VAS score and ODI in group C were higher than that in group A and B,but the differences did not reach statistical significance(p>0.05).Conclusion:After strict patient screening,the patients with degenerative lumbar central spinal stenosis underwent OLIF operation got radiologic results showing good indirect neuro decompression,and the clinical symptoms of patients improved significantly.The extent of central spinal canal decompression in patients with severe spinal stenosis was larger than that in patients with mild or moderate spinal canal stenosis.Patients with mild,moderate and severe stenosis achieved similar and good clinical results.After strict patient screening,severe lumbar spinal stenosis could be considered as the indication of OLIF.