Correlation between postoperative coronal balance variability and orientation of pelvic obliquity in degenerative lumbar scoliosis
Objective To investigate the correlation between postoperative coronal balance and variability of pelvic obliquity(PO)after one-stage posterior pedicle screw fusion surgery for degenerative lumbar scoliosis(DLS).Methods A retrospective analysis of 71 patients with DLS treated with single-stage posterior pedicle screw fixation in our hospital from January 2014 to January 2021 was conducted.Demographic data such as patient age,gender,fusion segments,upper instrumented vertebral(UIV),lower instrumented vertebra(LIV),osteotomy modality and a series of preoperative,postoperative and final follow-up radiographic parameters were collected as follows:pelvic obliquity angle(POA),main curve cobb(MC cobb),lumbosacral fractional curve(LFC),L4 tilt,L5 tilt,Trunk shift(TS),cervical 7 plumb line(C7PL),centre sacral vertical line(CSVL),thoracic kyphosis(TK),lumbar lordosis(LL),sagittal vertical axis(SVA),pelvic incidence(PI),sacral slope(SS),pelvic tilt(PT).The lower side of the bilateral iliac spine was identified as the PO direction.Relative position of TS and PO:TS/PO was defined as TS/PO ipsilateral when C7PL was on the low iliac spine side of PO,and TS/PO opposite when C7PL was on the high iliac spine side of PO.Patients were divided into coronal balance group(CB group)and coronal imbalance group(CIB group)according to TS≤3 cm or TS>3 cm after surgery.Demographic data and the radiographic parameters above were compared between the two groups,and the risk factors for postoperative CIB were investigated.Paired samples t-test was used for within-group before-after comparisons,independent samples t-test for between-group comparisons of continuous variables,and U-test when data were non-normal or variance was not homogeneous.Chi-squared test was used for dichotomous variables,and Fisher's exact test was used when the frequency was less than 5.Three groups were classified according to the C7PL variation from postoperative to final follow-up.Group A:C7PL close to the centre of S1>1 cm,Group B:C7PL variation<1 cm and Group C:C7PL deviation from S1.Pearson's correlation was used to analyse the correlation between PO direction and coronal balance variance during postoperative follow-up.Results The correction of main curve was(70.5±14.2)%in 71 patients with DLS undergoing one-stage posterior pedicle screw fusion surgery.The correction of LFC was(64.9±20.7)%.The incidence of CIB was from 23.9%to 35.2%.There was no significant difference in gender,age,fusion segments,follow-up time,UIV,LIV and osteotomy between CIB group and CB group(P>0.05).There were significant differences in preoperative LFC,postoperative L4 tilt,postoperative POA,preoperative and postoperative TS/PO orientation consistency(P<0.05).There was no significant differences in preoperative and postoperative main curve cobb angle,preoperative L4 tilt,preoperative and postoperative L5 tilt,preoperative TS,preoperative POA,and postoperative LFC(P>0.05).Grouped according to the coronal balance variability from postoperative to final follow-up,the three groups showed a significant difference in postoperative and final follow-up TS,postoperative POA,postoperative and final follow-up TS/PO orientation consistency(P<0.05).There was no significant differences in postoperative and final follow-up main curve cobb angle,LFC,L4 tilt,and L5 tilt(P>0.05).In group A,there were significant improvement in final follow-up TS and POA compared to the postoperative data,while there was no significant difference in group B.And in group C,there was significant aggravation from postoperative to final follow-up TS with significant improvement of POA.The correlation analysis of ΔTS and ΔPOA from postoperative to final follow-up was performed in the three groups by Pearson correlation coefficients,and the ΔTS was positively correlated with ΔPOA in Group A(r=0.807,P=0.000);there was no significant correlation between ΔTS and ΔPOA in Group B and Group C.Conclusions Preoperative TS/PO on the ipsilateral side of the trunk may be a risk factor affecting postoperative CIB recovery.Coronal balance self-correction during follow-up is affected by discrepancies in postoperative TS/PO orientation consistency.Specifically,consistent postoperative TS/PO direction facilitates coronal balance self-correction,whereas inconsistent postoperative TS/PO is disadvantageous for coronal balance self-correction.
万方数据
维普
