Comparison of unipedicular and bipedicular percutaneous kyphoplasty for treating osteoporotic vertebral compression fractures:a meta-analysis

Background Percutaneous vertebroplasty(PKP) has proved its effectiveness regarding minimal invasion,rapid pain reduction,safe cement augmentation,restoring vertebral height,and accelerating complete recovery of osteoporotic vertebral compression fractures(OVCFs).Whether unipedicular or bipedicular PKP provides a better outcome is controversial.Methods We searched PubMed,Cochrane Database of Systematic Reviews,Cochrane Central Register of Controlled Trials,Web of Knowledge,Chinese Biomedical Literature Database,and Wanfang Data from January 1980 to March2013 with "kyphoplasty", "unipedicular", "bipedicular", "compression fracture",and "randomized controlled trial".Risk of bias in the included studies was assessed according to a 12-item scale.Meta-analysis was performed.Dichotomous and continuous variables were calculated using the odds ratio(OR) and standardized mean difference(SMD),respectively.Results Seven studies involving 440 patients and 559 vertebral bodies met the criteria for inclusion.Among them,one randomized controlled trial had a high risk of bias and six a low risk.The pain visual analogue scale(VAS) SMDs were-0.02(P=0.88) for short-term follow-up(≤3 months) and 0.03(P=0.82) for long-term follow-up(≥ 1 year).Oswestry Disability Index(ODI) SMDs at short- and long-term follow-up were not statistically significant(-0.04,P=0.77 and-0.07,P=0.74,respectively).This meta-analysis showed greater polymethylmethacrylate volume(SMD-1.08,P=0.00) and operation time(SMD-2.40,P=0.00),favoring unipedicular PKP.Radiographic outcomes-preoperative kyphosis angle,restoration rate,reduction angle,loss of reduction angle-were not statistically different between the groups.Pooled analyses of cement leakage and subsequent adjacent OVCFs showed no significant differences between the groups,with OR=0.82(P=0.79) and OR=1.41(P=0.70),respectively.Conclusions This meta-analysis comparing unipedicular and bipedicular PKP demonstrated no significant differences regarding VAS,ODI,radiographic outcomes,or complications.Considering the longer operation time and radiation exposure with bipedicular PKP,we recommend unipedicular PKP over bipedicular PKP for treating OVCFs.