Clinical Outcomes And Complications Of Posterior Long-level Fixation And Fusion In Patients With Adult Degenerative Scoliosis

Objective:To evaluate the clinical outcomes and explore the risk factors of complications after posterior long-level fixation and fusion in patients with adult degenerative scoliosis(ADS),and provide support of improving clinical outcomes and reducing surgical complications.Methods:The first part was a retrospective study that included the clinical data of 41 patients with degenerative lumbar scoliosis(DLS)who underwent the surgical treatment of posterior transforaminal lumbar interbody fusion(TLIF)combined with Ponte osteotomy and long-level fixation from August 2011 to July 2016.Patients’ demographics characteristics included gender,age,bone mineral density(BMD),and comorbidities.This study measured the clinical functional outcomes of patients using the Oswestry disability index(ODI)and visual analog scale(VAS).Perioperative and follow-up statuses were recorded,and clinical outcomes were compared before surgery and at the last follow-up.Preoperative and postoperative anteroposterior and lateral long-cassette radiographs were reviewed.Correlation and linear regression analysis was performed on the patients’ difference of radiographic parameters before surgery and at the last follow-up.The category and number of early complications were collected and recorded.Patients were divided into two groups according to the occurrence of early complications.Potential risk factors were identified by univariate analysis after comparing the difference of clinical data in two groups.Late complications were collected and recorded at the last follow-up.Patients were divided into two groups according to state of coronal imbalance measured in the final follow-up.Univariate analysis was performed for the potential risk factors of postoperative coronal imbalance.Multivariate logistic regression analysis was performed to verify the independent risk factors of postoperative coronal imbalance.The second part was a retrospective study included patients with ADS who underwent posterior long-level fusion and instrumentation from December 2011 to December 2018.Patients were divided into two groups according to the occurrence of intra-and postoperative complications in 6 weeks.Patients’ demographics characteristics included gender,age,bone mineral density(BMD),and comorbidities.Preoperative assessment data included American society of anesthesiologists(ASA)risk grade,nutritional risk screening,deep vein thrombosis(DVT)risk grade,and operative risk assessment.Radiographic parameters included coronal Cobb angle,coronal balance distance(CBD),and sagittal vertebral axis(SVA).Intraoperative data included operation time,intraoperative blood loss and transfusion,level of decompression,osteotomy grade,number of instrumented and fusion vertebrae.Postoperative data included hospital stay,the times and amount of blood transfusion,the minimum value of postoperative hemoglobin and albumin.Potential risk factors were identified by univariate logistic regression analysis after comparing the difference of clinical data in two groups.Multivariate logistic regression analysis was performed to verify the independent risk factors of early complications.Results:In the first part,forty-one patients were included in this study,15 males and 26 females,the mean age was 63.02±8.20 years.The mean values of the functional outcomes,including the ODI and VAS scores,were significantly improved at the last follow-up.Strong correlations were found between each radiographic parameter.Differences in LL were strongly correlated with the differences in SVA and TPA(r = 0.617 and 0.528,respectively)and correlated with the differences in AVR,AVT and coronal Cobb angle(r = 0.449,0.442,and 0.397,respectively).Multiple linear regression analysis demonstrated that the differences in AVT and AVR were significantly correlated with the difference in LL,which was significantly correlated with the differences in SVA and TPA.Early complications incidence rate is 36.59% in this study.Patients were divided into two groups according to the occurrence of early complications.Compared the difference of data in two groups.There were significant difference between two groups in the level of instrumentation(P<0.05).The patients were divided into two groups according to whether coronal imbalance occurred at the last follow-up.There were significant differences in Cobb angle,AVT,LSC Cobb angle,L5 TA at pre-operation,and the difference of L5 TA and AVR at pre-and post-operation between the two groups(P<0.05).Univariate analysis showed that preoperative L5TA≥15° was the potential risk factor of post-operative coronal imbalance(P <0.05).Multivariate logistic regression analysis was performed on preoperative L5TA≥15°,the difference of L5 TA and AVR at pre-and post-operation.Preoperative L5TA≥15° was an independent risk factor of post-operative coronal imbalance,and the difference of AVR at preand post-operation was a protective factor of post-operative coronal imbalance.In the second part,64 patients with ADS who underwent the surgical treatment of posterior long-level fixation and fusion were enrolled,23 males and 41 females,the mean age was 60.78±7.85(50~78)years.Early complications were developed in 21 of 64 patients until 6 weeks after operation,the incidence rate is 32.81%(21/64).There were significant difference in parameters including preoperative nutritional risk screening≥1 score(42.86% vs 16.28%,P=0.021),operative risk assessment≥2 score(52.38% vs 25.58%,P=0.034),comorbidities(57.14% vs 25.58%,P=0.013),operation time(279.26±97.82.02 vs 238.79±59.32,P=0.034),and levels of instrumentation(8.14±1.62 vs 6.91±2.10,P=0.016).Univariate logistic regression analysis showed that preoperative nutritional risk screening score,operative risk assessment score,operation time,and levels of instrumentation were the potential risk factors of early complications from the variance with significant difference between the two groups.Analysis of the multivariate logistic regression showed that for every 1 point(OR=3.114,P=0.032)increase in preoperative nutritional score and 1 minute(OR=1.010,P=0.033)increase in operative time,the risk of early complications increased 2.11 times and 0.01 times respectively.Preoperative nutritional risk score and operation time were two independent factors of early complications after long-level fusion and instrumentation in ADS.Conclusion:Surgical treatment of posterior TLIF combined with Ponte osteotomy long-level fixation and fusion improved DLS patients’ quality of life scores.AVR and AVT correction is important for LL restoration and is significantly correlated with improved sagittal balance parameters(SVA and TPA).The occurrence of early complications is related to the level of instrumentation,and preoperative L5TA≥15° is an independent risk factor of coronal imbalance after TLIF combined with Ponte osteotomy long-level fixation and fusion surgery.The risk factors of early complications in long-level fusion and instrumentation for ADS included preoperative nutritional risk score and operation time.