A Clinical Study Of Selective Posterior Lumbar Curve Correction For The Reconstruction Of The Spine-Pelvis In The Sagittal And Axial Plane In Patients With Lenke 5 Scoliosis

[Backgrounds]There are three surgery’s goal in adolescent idiopathic scoliosis(AIS)patients: prevent the further Progress of curve;improve the appearance of deformity;maintain the global balance of the body.The global balance of the human body,including the head-spine-pelvis-lower limbs balance.Corresponding compensation occurs when one part runs into imbalance,which increases the load for the body.If breaks the compensatory limitation the body could bear,decompensated and its negative impacts including pain,mobility limitation,or even fracture fixation and other undesirable results would apply on human body.As the biomechanical foundation of the spine,the pelvis is the hinge of the coordination between the trunk and the lower limbs,and plays a very important role in the stability of the whole balance of the human body.As early as 1995,scholar introduced the concept of “pelvic vertebra” in scoliosis to recognize the pelvis as a vertebral body in the function and structure of the spine.Therefore,as an extension of the spine in AIS,the pelvis might also present a three-dimensional(coronal,sagittal,and axial)deformity.The study of the spine-pelvis in AIS patients is mainly focused on the sagittal and axial plane,because of the severe pelvic tilt of the pelvis in little patients with AIS.However,most of the studies of the spine-pelvis in the sagittal and axial plane were thoracic AIS patients.Lenke type 5C adolescent idiopathic scoliosis is characterized by a structural thoracolumbar/lumbar(TL/L)curve with a compensatory thoracic curve.Meanwhile,the lumbar spine is most close to the pelvic,whch the interaction between the spine and the pelvis may be most pronounced.There are few reports about the adjustment of spino-pelvic state after selective posterior TL/L curve instrumentation for the treatment of Lenke patients with type 5 AIS.[Objective]In the sagittal plane,measurement of spino-pelvic parameters before and after surgery,discuss the sagittal adjustment of pelvic after posterior selective TL/Lcurve instrumentation in patients with Lenke 5 AIS,analysis the sagittal correction TL/L curve to estimate the extent of pelvic sagittal state.Meanwhile,observe the change of cervical curve,analysis of its influencing factors.In the axial plane,measurement of spino-pelvic parameters before and after surgery,Understand the pelvic axis rotational effects after posterior selective TL/L curve,expose the factors that influence the passive and spontaneous rotation of the pelvic.Meanwhile,analyze whether the abnormal axial rotation of the pelvis is able to predict the postoperative coronal or shoulder imbalance.[Methods]1.In the sagittal plane,a retrospective analysis of selective posterior TL/L curve fixation in patients with Lenke type 5 AIS.The parameters measured on the spinal sagittal radiographic images were as follows: cervical curve(C2-C7 lordosis),proximal thoracic kyphosis(Pr-TK),thoracic kyphosis(TK),global thoracic kyphosis(GL-TK)、thoracolumbar junction(TLJ),lumbar lordosis(LL),Lumbar lordosis within fusion(LLWF),Lumbar lordosis below fusion(LLBF),and sagittal vertical axis(SVA).The pelvic sagittal radiographic parameters were measured by pelvic incidence(PI),sacral slope(SS),and pelvic tilt(PT).Preoperative and postoperative radiographic parameters were compared using paired t-tests and Mann-Whitney U tests when appropriate.Categorical data were analyzed by using the Chi-square test.A correlational analysis was conducted using a Pearson test.Logistic regression analysis was carried tp show risk factors for preoperative KCS(and developing a KCS or LCS).p<0.05 was considered statistically significant.Logistic regression model was used for multivariatel analysis of risk factors for postoperative unrecovered anteverted pelvis and new anteverted pelvis.2.In the axial plane,The parameters measured on the spinal coronal radiographic images were as follows: thoracic apex rotation(TAR),lumbar apex rotation(LAR),lower instrumented vertebral rotation(LIV-R),upper instrumented vertebral rotation(UIV-R),upper end vertebra rotation in lumbar curve(LUEV-R),lower end vertebra rotation in lumbar curve(LLEV-R),and pelvic axial rotation(PAR).The Cobb angle of the patients was measured and the correction rate(CR)and the flexibility rate(FR)of the curve were measured.Measurement of radiographic radiographic shoulder height(RSH),T1 tilt(T1 tilt),trunk shift(TS),thoracic apex vertebra translation(TAVT),lumbar apex vertebra translation(LAVT),and clavicle angle(CA).Preoperative and postoperative radiographic parameters were compared using paired t-tests and the Mann-Whitney U test when appropriate.Categorical data were analysed using the x2 test.Correlation analysis was performed using a Pearson test.1.In the sagittal plane,the mean preoperative PI,PT,and SS were 46.00 ± 9.50,8.20 ± 6.10,and 37.80 ± 7.10,respectively.25% of patients showed the anteverted pelvis,whereas the other 75% showed the normal pelvic state.The mean postoperative PI,PT,and SS were 47.10 ± 10.10,6.80 ± 8.80,and 40.20 ± 8.50,respectively.However,42% of patients showed the retroverted pelvis,53% of patients showed the normal pelvic state,and 5% of patients showed the retroverted pelvic condition.Pearson’s correlation analysis was also performed from spino-pelvic sagittal parameters for all patients.PI was related to PT and SS preoperatively and postoperatively.However,there was no significant correlation found between PT and SS.PI and SS were correlated with LL preoperatively and postoperatively.LL was no related to PT preoperatively,but slightly related to PT postoperatively.There were no significant correlation found between TK and the pelvic parameters preoperatively and postoperatively.TK was found to be significant related to LL preoperatively and postoperatively.Four patients showed the recovered anteverted pelvis,fourteen patients showed the unrecovered anteverted pelvis(unrecovered-AP).Sixteen patients occurred new anteverted pelvis(New-AP).Logistic regression analysis has yielded 2 factors that were significantly associated with the risk of postoperative unrecovered of pelvic anteverted,including increased LL and increased SS.There were 4 factors that were significantly associated with the risk of postoperative New-AP,including LL postoperatively,increased LL,LLBF,and increased SS.There were no significant differences between the preoperative and immediate postoperative C2-C7 lordosis and between the preoperative and last follow-up C2-C7 lordosis.However,there was a significant difference between the immediate postoperative and last follow-up C2-C7 lordosis.Significant correlations were found between the preoperative C2-C7 lordosis and T1-slope and between the last follow-up C2-C7 lordosis and T1-slope.There were no significant correlations between the preoperative C2-C7 lordosis and Pr-TK,between the immediate postoperative C2-C7 lordosis and Pr-TK,and between the last follow-up C2-C7 lordosis and Pr-TK.Significant correlations were found between the preoperative C2-C7 lordosis and TK and between the last follow-up C2-C7 lordosis and TK.Significant correlations were found between the preoperative C2-C7 lordosis and Gl-TK and between the last follow-up C2-C7 lordosis and Gl-TK.There were no significant correlations between the preoperative C2-C7 [Result] lordosis and LL,between the immediate postoperative C2-C7 lordosis and LL,and between the last follow-up C2-C7 lordosis and LL.There were no significant correlations between the preoperative C2-C7 lordosis and The pelvic sagittal radiographic parameters(PI,PT and SS).The T1-slope,TK,and Gl-TK in the LCS group were considerably greater than those for the KCS group.Logistic regression analysis yielded 2 factors that were significantly associated with the risk of developing a kyphotic cervical spine,including T1-slope and Gl-TK.In the KCS group,The T1-slope in the recovered group was considerably greater than that in the unrecovered group.However,the logistic regression analysis yielded no factors that were significantly associated with the risk of developing a LCS.2.In the axial plane,In all patients,the immediately postoperative PAR and TAR were significantly different from the preoperative PAR and TAR.However,no significant change was found in PAR and TAR from the immediately postoperative period to the last follow up.The LAR showed significant differences between the preoperative and immediately postoperative periodand between the immediately postoperative period and the last follow-up.The LLEV-R,LUIV-R,and LLIV-R showed significant improvement in the immediately postoperative period and no significant change in the last follow-up postoperative period.Significant correlations were found between the preoperative PAR and LAR,the immediately postoperative PAR and LAR,and the last follow-up PAR and LAR.In the preoperative and last follow-up measurements,no significant correlations were found between the PAR and TAR.The PAR values were not correlated with thoracic flexibility(TF)and lumbar flexibility(LF)in the preoperative,immediately postoperative,and last follow-up periods.The PAR values were also not related to the thoracic correction rate(TCR)and lumbar correction rate(LCR)in the preoperative,immediate postoperative,and last follow up period.When comparing the PAR-L group to the PAR-R group in the preoperative period,found the LAR in the PAR-L group was considerably greater than in the PAR-R group,whereas the LF in the PAR-L group was smaller than in the PAR-R group.However,the LAR in the PAR-L group was significantly greater than in the PAR-R group.When comparing the N-group to the A-group in the preoperative period,no significant differences were found in age,sex,Risser sign,or the level of the end vertebra in the lumbar curve.There were also no significant differences in the thoracic Cobb angle,lumbar Cobb angle,TAR,LAR,LUEV-R,LLEV-R,CB,RSH,LIV translation,LIV tilt,T1 tilt,TS,TAVT,LAVT,CA,thoracic flexibility rate(TFR),or lumbar flexibility rate(LFR).At the last follow up after surgery,there were no significant differences found in age,sex,Risser sign,or the level of instrumented vertebra in the lumbar curve.There were also no significant differences in the thoracic Cobb angle,TAR,LAR,UIV-R,LIV-R,TS,TAVT,LAVT,LIV translation,LIV tilt,incidence of both coronal and shoulder imbalance,TCR,loss of thoracic correction,or loss of TL/L correction.However,the incidence of coronal imbalance and shoulder imbalance in the A-group was significantly greater than in the N-group.The lumbar Cobb angle in the A-group was significantly smaller than that in the N-group.The correction rate of the TL/L curve in the A-group was also significantly greater than in the N-group.[Conclusions]1.In the sagittal plane,the pelvic state may be adjusted after the selective posterior fusion of thoraolumbar/lumbar(Lenke 5C)curves in idiopathic scoliosis.LL was correlated with pelvic parameters preoperatively and postoperatively.So,it is very important for evaluating the lumbar lordosis and pelvic morphology before surgery in order to maintain or recover the spinopelvic sagittal balance.However,we find that it is difficult to improve the anteverted pelvis in patients with increased LL more than 11.60 or increased SS more than 4.70 after surgery.The anteverted pelvis state will be generally created by posterior correction surgery when patients with LL more than 63.50 or increased LL more than 15.60 or increased SS more than 9.00.We should avoid to the pelvic retrovertion when a large LL was corrected to very smaller than preoperative by posterior signal thoracolumbar/lumbar curve instrumentation and fusion.Meanwhile,Overcorrection of thoracolumbar/lumbar sagittal alignment can improve thoracic sagittal alignment,which affects the CSA in patients with Lenke 5C AIS.C2-C7 lordosis is strongly correlated with T1-slope.C2-C7 lordosis of Lenke 5C AIS is related to the global thoracic sagittal alignment rather than TK and Pr-TK.Despite the significant increase in thoracic sagittal alignment after surgery,only a minority of patients exhibited a restored LCS.Eventually,spontaneous adjustment of CSA is limited because of the inherent rigidity of the cervical spine.2.In the axial plane,The partial transverse plane pelvic rotation in Lenke 5C AIS might be primary.The pelvis was first rotated in the same direction as the corrective derotational load to the TL/L curve andthen underwent a reverse rotation to adapt to the new spinal or trunk imbalance.Multiple factors influenced the transverse plane pelvic rotation in AIS.The preoperative lumbar flexibility and lumbar apex rotation might be the most important factors affecting the pelvic axial rotation.Abnormal preoperative pelvic axial rotation might lead to spinal or shoulder imbalance after selective posterior TL/L curve correction.Whether excessive correction of the TL/L curve could affect the shoulder balance postoperatively remains unclear.