Effects Of Preoperative Adjacent Segment Facet Joint Degeneration And Postoperative Spine-Pelvic Parameters On Adjacent Segment Disease After Lumbar Fusion

BackgroundWith the extensive development of Posterior lumbar interbody fusion（PLIF）,its clinical efficacy has been widely recognized.Adjacent Segment Disease（ASD）after postoperative fusion has attracted more and more attention.Current risk factors for ASD include fusion length,fusion technique,preoperative disc degeneration,adjacent segment decompression,iatrogenic destruction,and age.But the exact risk factors have not been accurately determined.ObjectiveTo investigate the influence of preoperative adjacent segment facet degeneration and postoperative spine-pelvis parameters on adjacent segment disease after lumbar fusion.MethodsA total of 138 patients who underwent L5/S1 Posterior lumbar interbody fusion（PLIF）in the First Affiliated Hospital of Xinxiang Medical College from June 2016 to June 2019 were selected as the study subjects.Postoperative outcomes were assessed by Visual Analogue Score（VAS）and Oswestry disability index（ODI）.Through follow-up,18 patients with postoperative ASD were determined as the observation group,and 120 patients without postoperative ASD were determined as the control group.The age,gender,follow-up time,preoperative L4/5 disc degeneration and preoperative L5 cephalic facet degeneration were collected.The postoperative lumbar lordosis Angle（Lumbar lordosis,LL）,pelvic incidence Angle（Pelvic Incidence,PI）,pelvic inclination Angle（Pelvic Tilt,PT）and sacral inclination Angle（Sacrum Slop,SS）were tested by χ2 and independent sample T test,Wilcoxon sign rank sum test was used for grade variables,and Spearman’s correlation test was used for grade correlation analysis,to compare whether there was statistical difference between the two groups.Binary logistic regression was used for analysis.Results（1）There were no significant differences in gender,age and follow-up time between the experimental group and the control group（P > 0.05）.（2）There was no significant difference in the grade distribution of preoperative intervertebral disc degeneration between the experimental group and the control group（P > 0.05）.There were statistically significant differences in grade distribution of facet joint degeneration in adjacent segments before surgery（P<0.05）.（3）There was a positive correlation between the preoperative grade of degeneration of adjacent segment facet joints and the occurrence of ASD（P < 0.05）.（4）The postoperative lumbar lordosis Angle（LL）of the observation group and the control group was 36.05°±4.22° and 38.73°±4.72°,respectively,and the difference was statistically significant（P < 0.05）.Postoperative PI-LL were 11.50°±6.25° and 5.18±4.19°,respectively,with statistical significance（P < 0.05）.（5）Logistic regression analysis showed that postoperative LL,PI-LL and preoperative degeneration of adjacent facet joints were risk factors for lumbar fusion（P< 0.05）.Conclusion（1）The degeneration of the facet joints of adjacent segments before surgery increases the probability of postoperative ASD,and the degree of degeneration is positively correlated with the probability of postoperative ASD.（2）Small LL and PI-LL after PLIF will increase the probability of postoperative ASD.After PLIF,sufficient LL should be restored to maintain the sagittal balance of the spine and pelvis.