Risk Factors For Height Re-loss Of The Augmented Vertebrae In Long-term After Percutaneous Vertebroplasty For Treatment Of Osteoporotic Vertebral Compression Fractures(OVCFs)

Objective To evaluate the height loss of the augmented vertebrae after percutaneous vertebroplasty(PVP)for osteoporotic vertebral compression fracture(OVCF)in longterm and analyze its related risk factors.Methods All patients diagnosed with fresh painful osteoporotic compression fracture by clinical and imaging examination and receiving percutaneous vertebroplasty in Department of Interventional and Vascular Surgery in Zhongda Hospital Southeast University were retrospectively reviewed from January 2009 to December 2018,with at least three years follow-up.The kyphosis Cobb angle and the height of anterior,middle and posterior of objective vertebra were measured in the midsagittal plane of the reformatted CT images before and after the surgery(in 3 days)and at the last follow-up.99 patients with 165 objective vertebra were divided into height re-loss group(40/165)and maintain group(125/165)according to whether the height loss of objective vertebra is more than 15% at the last follow-up compared with postoperation(in 3 days).The following covariates were reviewed: Sex,age,body mass index(BMI),the location of augmented vertebrae(thoracolumbar / nonthoracolumbar segment),bone mineral density(BMD),intravertebral vacuum cleft sign(IVC),surgical approach(unilateral / bilateral),cement dosage,cement distribution(solid mass / diffusion),cement distribution(symmetrical / lateral),relationship between cement and endplate,cement intervertebral leakage,severity of preoperative vertebral compression,postoperative height reduction rate and angle reduction rate.Binary logistic regression analysis was used to determine the relative risk of height re-loss of cemented vertebrae.Results Bone mineral density index(BMI),the position of augmented vertebrae,intravertebral vacuum cleft sign(IVC),cement distribution(solid mass / diffusion)and the relationship between cement and endplate are related factors.Logistic multivariate analysis indicate that high BMD is a protective factor(p=0.012,OR=0.556),IVC(p=0.035,OR=4.107),solid mass cement distribution(p=0.017,OR=4.107),cement contact with upper endplate(p=0.028,OR=3.973),cement contact with lower endplate(p<0.01,OR=8.746),none contact with endplate(p<0.01,OR=89.66)are independent risk factors.Conclusion Height re-loss occurred to a portion of augmented vertebral bodies after PVP,mostly at the anterior margin of the vertebral body.High BMD is a protective factor while IVC,solid mass cement distribution,cement contact with upper endplate,cement contact with lower endplate,none contact with endplate are independent risk factors.