Analysis Of The Influence Of Lumbar Lordosis Reconstruction On Spine-pelvis Sagittal Balance After Lumbar Fusion

BackgroundLumbar degenerative disc disease is a common disease in orthopedics,which seriously affects patients’health and quality of life.Lumbar lordosis is one of the important structures of the spine,which can disperse the pressure of the lumbar spine and maintain the center of gravity.Intervertebral disc degeneration can have a significant impact on lumbar lordosis.Therefore,this study aims to investigate the effect of lumbar lordosis reconstruction on the spine-pelvis sagittal balance after lumbar fusion and its correlation with clinical outcomes.Methods1.Retrospective analysis of 54 patients treated with L4-S1 segmental fusion internal fixation.The ideal LL（calculation formula:ideal LL=0.62×PI+29°）and relative lumbar lordosis（RLL）（RLL=actual measured LL-ideal LL）were calculated according to the Global Alignment and Proportion（GAP）.Based on GAP and RLL values,patients were divided into three groups A,B,and C:group A:lumbar lordosis balance group,RLL between-14°and 11°;group B:lumbar lordosis deficiency group,RLL between-25°and-14.1°;group C:lumbar lordosis severe deficiency group,RLL<-25°.2.The age,gender,follow-up time,length of hospital stay,BMI,disease type,surgical procedure,interbody fusion rate,and postoperative complications were recorded for the three groups of patients.3.By comparing the lumbar parameters(including LL,LLL,adjacent segmental angles L_3-4)of the three groups of patients before the operation,1 month after operation,and the last follow-up,the influence of the local fusion curvature of the lumbar spine on the structure of the lumbar spine was evaluated.4.By comparing the TK,PI,PT,SS,and SVA of the three groups of patients preoperative and the last follow-up,to evaluate the effect of lumbar lordosis reconstruction on the thoracic spine,pelvis,and overall sagittal balance.5.By comparing the VAS scores and ODI scores of the three groups of patients preoperative,1 month after operation,6 month after operation,and the last follow-up,to evaluate the difference in clinical curative effect among the three groups.6.Evaluate and visualize the correlation between RLL and SVA,VAS and ODI scores by R software,and explore the relationship between lumbar lordosis reconstruction and sagittal balance and clinical efficacy.Results1.All included cases were operated with PLIF or MIS-TLIF.All patients completed the surgery successfully,and none had complications such as fusion device displacement and screw or connecting rod breakage.There were no statistically significant differences in age,gender,follow-up time,length of hospital stay,body mass index,disease type,and surgical procedure compared among the three groups（P>0.05）.There were no statistically significant differences in the incision superficial infection rate,cerebrospinal fluid leakage rate,neurological symptom rate,and excellent intervertebral fusion rate compared among the three groups after surgery（P>0.05）.2.There was no statistically significant difference in preoperative LLL between the three groups（P>0.05）.Compared to preoperative,postoperative LLL in group A was significantly reconstructed（P<0.05）.Compared to groups B and C,postoperative LLL in group A was reconstructed to a greater extent（P<0.001）.The differences were not statistically significant compared with the preoperative LL among the three groups（P>0.05）.LL at 1 month after operation was significantly greater in group A than in groups B and C（P<0.001）.All three groups had an increase in last follow-up LL compared to their respective 1month after operation LL（P<0.05）,butΔLL（the last follow-up LL minus 1 month after operation LL）was lower in group A（P<0.001）.The adjacent segmental angle results showed thatΔL_3-4(the last follow-up L_3-4minus 1 month after operation L_3-4)was significantly smaller in group A than in groups B and C（P<0.001）.3.Compared with the preoperative TK,PI,PT,and SS in the three groups,the differences between the groups were not statistically significant（P>0.05）.In group A,the TK and SS at the last follow-up were significantly increased,and the PT was decreased compared with the preoperative,and the differences were statistically significant（P<0.05）.In group B,the PT at the last follow-up was decreased compared with the preoperative,and the differences were statistically significant（P<0.05）.In group C,the TK,PT,and SS at the last follow-up were not significantly changed compared with the preoperative（P>0.05）.In group A,the PT at the last follow-up was smaller than those in groups B and C,and the TK at the last follow-up was larger than those in groups B and C,and the differences were statistically significant（P<0.05）.4.The last follow-up SVA in group A was significantly lower than that before surgery（P<0.05）.Comparison between groups showed that for the last follow-up SVA,group A was significantly smaller than groups B and C（P<0.05）.The correlation analysis showed that RLL was negatively correlated with the last follow-up SVA（R=-0.480,P<0.001）.5.The VAS and ODI scores of the three groups were significantly decreased after the operation（P<0.05）.At the last follow-up,compared with the B and C groups,the VAS and ODI scores of group A were significantly lower（P<0.05）.The Correlation analysis showed that RLL was negatively correlated with the VAS and ODI scores at the last follow-up（P<0.05）.Conclusion1.Lumbar lordosis reconstruction is beneficial to reduce the compensation of the spine-pelvis structure and maintain the sagittal plane balance.2.For patients with better lumbar spine mobility,appropriate intraoperative reconstruction of the curvature of the degenerated segment may reverse the compensatory hyperextension of the adjacent segment,which plays an important role in reducing the incidence of ASD.3.Reconstruction of the curvature of the degenerated segment during lumbar surgery is helpful in improving the outcomes of patients.