Analysis Of The Effect Of Reduction Degree Of Low-grade Lumbar Spondylolisthesis On Its Clinical Efficacy And Restoration Of The Balance Of Spin-pelvis Alignment

Objective:To investigate whether the degree of reduction affects the clinical outcomes and the reconstruction of the balance of the spinal-pelvic alignment for lumbar spondylolisthesis.Methods:A retrospective study was performed to analyze the clinical data of patients who have underwent surgical treatments for lumbar spondylolisthesis from January 2014 to June 2016 in the Second Hospital of Jilin University.According to the PI value,the patients divided into two groups: group A,PI value ? 50°,group B,PI value > 50°.Then,according to whether the degree of reduction exceeds 50% of the displacement of the vertebral body,it is divided into two subgroups,subgroup 1,the degree of reduction < 50% of the displacement of the vertebral body,subgroup 2,the degree of reduction ?50% of the displacement of the vertebral body.The study included 14 people in the A1 group,18 in the A2 group,38 in the B1 group,and 30 in the B2 group.The follow-up data were collected,including the VAS,JOA score,ODI value and spine-pelvic parameters PI,PT,SS,LL.These data were measured at the time before operations,1 year and 2 years after the operations,and the last follow-up.All the measured results were analyzed with SPSS 25.0 for mac software,and P < 0.05 was considered as statistically significant.Results:Among all the patients,there were no differences between the demographic characteristics and clinical symptom scores before operations.The follow-up time ranged from 32 months to 50 months.There was no significant difference between the groups.In the first year after surgery,all patients achieved favorable clinical results,but in the mid-term efficacy,the clinical outcomes of the A1 group was better than the A2 group,and the clinical efficacy of the B2 group was better than that of the B1 group.After surgery in group A2 and group B1,it is easier to change to flatback deformity as the LLs show they decreased sharply.In terms of spinal pelvic parameters,the PI value remained unchanged,and all patients showed a decrease in PT and an increase in SS after surgery.The spinal-pelvic parameters in A1 and B2 groups were more likely to change into the values among the normal population at postoperative follow-ups.Conclusion:As for the treatment of lumbar spondylolisthesis,the degree of reduction of patients with low-PI should be ? 1/2 of the vertebral body displacement,while the degree of reduction of patients with high-PI should be > 1/2 vertebral body displacement,which could more likely achieve better clinical outcomes,and could reconstruct the spine-pelvic sagittal balance,and delay the progression of postoperative lumbar degeneration.