A Clinical Study Based On Surgical Strategy And Surgical Techniques In Prevention Of Adjacent Segment Degeneration In Lumbar Spine

Lumbar fusion has been the most common surgical procedure for the treatment of lumbar degenerative disease over the past two decades.However,adjacent segment degeneration(ASD)after lumbar fusion surgery is a major factor for the revision surgery,restricting the long-term clinical outcomes.Several risk factors associated with ASD have been reported in previous studies,mainly covering two categories:patient’s personal factors and factors related to lumbar surgery.The factors related to surgery mainly include surgical technology factors(facet j oint violation and poor restoration of sagittal alignment,such as poor restoration of lumbar lordosis and segmental lordosis angle)and surgical strategy factors(application of nonfusion technology).This study aimed to investigate the methods of ASD prevention based on restoration of segment lordosis angle and use of non-fusion technology through a medium and longterm follow-up study of patients after lumbar surgery in our hospital.This paper is organized as follows.1.Comprehensive multi-factor analysis of the factors affecting postoperative segment lordosis restoration with oblique lateral lumbar interbody fusion and preoperative quantitative failure risk prediction at L4-5 levelObjective:This study aimed to comprehensive multi-factor analysis of the correlation of cage-related variables with restoration and maintenance of segment lordosis angle(SLA)in oblique lateral lumbar interbody fusion(OLIF).Then to develop a quantitative score system systems to predict the failure risks of L4-5 levelMethods:Seventy-three patients(93 segments)with lumbar degenerative disease who underwent OLIF at our hospital between January 2015 and December 2019 were included.Radiographic parameters including disk height(DH),foraminal height(FH),segment lordosis angle(SLA)and intervertebral height index(IHI),cage center point ratio(CPR),cage subsidence(CS),and L1 CT Hounsfield Unit(HU)were measured.Results:Postoperative DH,FH,and SLA were significantly improved,however significant reduction was observed at the last follow-up.CPR and cage subsidence were the main factors influence postoperative SLA show in regression analysis.CPR was positive correlation with SLA increased(r=0.526,P<0.01).Cage subsidence was 12.9%(12/93)at last follow-up and the SLA reduction was significant larger in subsidence segment(4.2±1.0°vs 1.7±2.1°,P<0.05).Logistic regression analysis showed CPR<50%,L1 CT HU<110 and cage height>preoperative MDH were risk factor of cage subsidence.Cage placed anteriorly(CPR≥50%)with larger SLA increased and lower incidence of cage subsidence than posterior(5.9±3.9° vs 4.2±3.2°,P<0.05;1.8%vs 28.9%,P<0.05,respectively).Then a quantitative scoring system was developed based on CPR associated factors of 67 L4-5 OLIF patient and score was negatively correlated with CPR(r=-0.557,R2=0.310,P<0.01).Patients with>5 points were more likely to have CPR<50%(69.0%vs 15.7%,P<0.05)and higher risk of cage subsidence(20.7%vs 2.6%,P<0.05).Conclusion:Cage position was the most important factor for postoperative SLA restoration in OLIF.The quantitative score system could predict the risk of placing cage at posterior position causing failure to restoration of sagittal alignment at L4-5 level,we thought it could provide more information for surgeon in preoperative planning.2.Dynesys dynamic stabilization versus fusion for lumbar degenerative diseases treatment-a medium-long term studyObjective:This study aimed at comparing the medium-long term outcome of Dynesys dynamic stabilization and fusion operation in treatment of lumbar degenerative diseases.Methods:Patients in the Department of Orthopaedics of Tongji hospital from January 2013 to December 2019 due to lumbar degenerative diseases including lumbar disc herniation,lumbar spinal stenosis and lumbar degenerative spondylolisthesis(grade Ⅰ)were collected.Patients were divided into Dynesys group and fusion group according surgical procedures.The clinical results of preoperative and last follow-up were collected by Oswestry disability index(ODI)and visual analog scale(VAS score for back pain and leg pain).To compared the medium and long-term outcomes between Dynesys group and fusion group.Results:95 patients were included in this study.One patient underwent Dynesys operation was diagnosed internal fixation broken at 5-year follow-up,he was asymptomatic but excluded according to relevant standards.A total of 94 patients with mean 48.6 ± 22.5 months follow-up left.36 patients with 41 surgical segments underwent Dynesys and 58 patients with 70 surgical segments underwent lumbar interbody fusion(transforaminal/oblique lumbar interbody fusion,T/OLIF).The symptoms were significantly improved at the last follow-up comparing pre-operatively(P<0.05).The VAS score(low back pain and leg pain)was decreased from 4.1 and 6.4 to 1.3 and 0.6,and the ODI was decreased from 62.5 to 9.4.There was no significant difference in VAS score(low back pain and leg pain)and ODI index between the two groups at the last follow-up(P>0.05).Conclusion:This study compared the medium and long-term clinical outcomes difference between Dynesys group and fusion group in treatment of lumbar degenerative diseases.Dynesys operation could achieve satisfactory medium and long-term outcomes.3.The effect of Dynesys dynamic stabilization and fusion on adjacent segment-A clinical study based on standing and different sitting position.Objective:To analyze the different of the lumbo-pelvic sagittal parameters between Dynesys and fusion patients based on lumbar dynamic X-ray,standing and different sitting position.Then to identify the risk factors of ASD.Methods:Patients underwent 1 or 2 level fixations at L3-S1 level caused by lumbar disc herniation with or without segment instability and spinal stenosis in the Department of Orthopaedics of our hospital from January 2013 to December 2019 were collected.Patients were divided into Dynesys group and fusion group according surgical procedures.All of patients underwent commonly lumbar lateral and dynamic X-ray.Additional lumbar X-ray in standing,erect sitting and nature sitting position were also obtained.Clinical outcomes and radiographic parameters were analyzed.Radiographic parameters including:pelvic incidence(PI),pelvic tilt(PT),lumbar lordosis(LL),up residual lumbar lordosis angle(URLA)and lumbar lordosis apex position.Results:A total of 77 patients were recruited with a mean 51.4±22.8 months follow-up.33 patients with 37 surgical segments underwent Dynesys and 44 patients with 52 segments underwent T/OLIF.Patients in two group got satisfactory outcomes at last follow-up.Dynesys group keep partial surgical ROM comparing fusion group(5.6±3.1° vs 0.1 ±0.4°)and the postoperative adjacent segment ROM was not significant different between two group.Dynesys group showed larger changes in LL,URLA and PT compared with the fusion group during position change(P<0.05).The incidence of ASD was 12.1%(4/33)in the Dynesys group,lower than that in the fusion group(31.8%,14/44).Preoperative adjacent segment degeneration and apex position unchanged or moved superiorly during standing to natural sitting were associated with ASD(P<0.05)in fusion group.The apex position unchanged or moved superiorly caused by smaller changes in LL was more likely shown in the fusion group during standing transformed to nature sitting(P<0.05).Preoperative lumbar ROM was correlated with postoperative change in LL and receiver operating characteristic curve of preoperative lumbar ROM/PI predicting apex location unchanged or moved superiorly with a curt-off 0.66.Patients in fusion group with preoperative lumbar ROM/PI<0.66 was prone to have apex location unchanged or moved superiorly(10/7 vs 3/24,P=0.002)and higher incidence of ASD(47.1%vs 22.2%).Conclusion:It was the first time to compare sagittal lumbo-pelvic differences between the Dynesys and fusion groups during standing transformed to sitting position.The difference of lumbar profile change in fusion patients may affects the load distribution in different lumbar segment,and it was found associated with ASD.Preoperative evaluation through lumbar ROM/PI could assess postoperative lumbar profile change and we believe it provide a new perspective for surgeons in surgical planning.