Risk Factors Analysis On Vertebral Refracture After PKP

Background and Objective:Osteoporotic vertebral compression fracture (OVCF) is a common complication of patients with osteoporosis. Some acute osteoporotic vertebral compression fractures often lead to severe and persistent back pain. Conservative treatment was the main treatment in the past. It can not completely relieve symptoms. Percutaneous vertebralplasty and percutaneous kyphoplasty become the main treatment method of OVCF. Compared with conservative treatment, They can rapidly relieve pain caused by fractures, clinical effect is remarkable. In recent years, We have found some complications of PKP through long-term clinical follow-up, There are more and more vertebral refractures after PKP. This study aims to analyze risk factors on vertebral refracture after PKP and discuss its clinical significance in order to prevent vertebral refracture.Methods:We choose patients who suffer from PKP in the306th hospital spine center of PLA from January1,2009to June30,2011, because of osteoporotic vertebral compression fracture. We have followed up1year at least, until December31,2012. Vertebral refracture group consist of refracture patients who have symptoms again and their clinical datas are intact, total of18cases.10cases have adjacent refractures.8cases have remote refractures. Control group consist of patients who has not found symptoms, and their clinical datas are intact, total of74cases.We apply the hospital electronic medical record system to collect patients’ clinical data as potential risk factors of vertebral refracture after PKP. All data are collected and measured by the same physician, including:gender, age, bone mineral density T score, surgical vertebral body position (thoracic lumbar segment/non thoracic lumbar segment) and bone cement dosage, bone cement injection mode (single/double side), bone cement leakage, vertebral fracture number, vertebral surgery number, postoperative VAS score, glucocorticoid use history, preoperative vertebral anterior height and postoperative change degree, preoperative spinal sagittal angle and postoperative angle recovery degree.Statistical processing:single factor analysis using t-test, chi-square test, continuity correction chi-square test, Fisher’s exact test, measurement data using independent sample t test and enumeration data using chi-square test, continuity correction chi-square test, Fisher’s exact test, applying binary logistic regression to analyse multiple factors(all-enter method). To put the potential risk factors with the single factor analysis of p<0.1into the binary logistic regression analysis, p<0.05as statistically significant difference.Results:Through the single factor analysis (table.1,2) we have found that vertebral fracture number, surgical vertebral body, bone mineral density, local cobb angle, vertebral anterior height change and bone cement leakage are statistically significant difference (p<0.05). we put the potential risk factors with the single factor analysis of p <0.1into multiple factors logistic regression analysis (table.3), have found that BMD is much lower and the incidence of bone cement leakage is much higher in the refracture groups, statistically significant difference (p<0.05). The odds ratio is0.159,6.502, respectively.In order to reveal further PKP on the effect of vertebral body without surgery, we divide fracture group into adjacent segmental vertebral refracture and remote segmental vertebral refracture group. Through analysis and comparison in the two groups (table.4), we have found bone cement leakage are statistically significant difference (p=0.013), and adjacent segmental bone cement leakage to fracture group was obviously higher than remote segmental fracture group (table5).Conclusion:This study have found that low bone mineral density and bone cement leakage are risk factors of vertebral refracture after PKP.