Changes in spinopelvic sagittal plane parameters after percutaneous kyphoplasty for osteoporotic vertebral compression fractures and their impact on secondary fractures of adjacent vertebral bodies

English Keywords:Osteoporotic vertebral compression fracture  Spinopelvic sagittal parameters  Percutaneous kyphoplasty of vertebral body  Secondary fracture of adjacent vertebrae

English Abstract:

  【Abstract】 Objectives: To observe the changes in spinopelvic sagittal plane parameters after percutaneous kyphoplasty(PKP) in patients with osteoporotic vertebral compression fracture(OVCF), and to explore their impacts on adjacent vertebral compression fracture(AVCF). Methods: 201 patients with OVCF who underwent PKP in our hospital from May 2018 to November 2022 were selected as the study subjects. The patients were followed up for 2 years after PKP surgery, and were divided into AVCF group(n=44) and non AVCF group(n=157) based on whether AVCF occurred during the follow-up period. The spinopelvic sagittal parameters, visual analogue scale(VAS) scores, and Oswestry disability index(ODI) were compared between the two groups of patients before operation and at 1 week, 1 month, and 3 months after surgery. Pearson correlation test was used to analyze the correlations between the spinopelvic sagittal parameters in the AVCF group and non AVCF group at 3 months after surgery; Logistic regression analysis was used to evaluate the correlation between spinopelvic sagittal parameters and AVCF after PKP surgery. The receiver operating charactertics(ROC) curve was drawn to analyze the predictive value of various spinopelvic sagittal parameters for AVCF in patients with OVCF after PKP. Results: The baseline VAS score and ODI of patients in the AVCF group were significantly higher than those in the non AVCF group(P<0.05). 3 months after surgery, the VAS score and ODI of both groups were significantly reduced, and the non AVCF group was significantly lower than the AVCF group(P<0.05). There were significant differences in pelvic tilt(PT), sagittal vertical axis(SVA), T1 pelvic angle(TPA), sacral slope(SS), lumbar lordosis(LL), and pelvic incidence(PI) between the two groups at different time points(P<0.05). The non AVCF group showed a significant difference in thoracic kyphosis(TK) before and after operation(P<0.05). There was no significant difference in thoracolumbar kyphosis(TLK) and PT(P>0.05), while there were significant differences in SVA, PI, TPA, LL, SS, and TK(P<0.05) between the two groups of patients at the same time points. In the non AVCF group, SVA was associated with TPA, TK, TLK, LL, and PT, TPA was associated with TK, TLK, LL, PI, SS, and PT, TK was associated with TLK, PT, and SS, TLK was associated with LL, PI, and PT, LL was associated with PT and SS, and PT was associated with SS at 3 months after surgery(P<0.05). In the AVCF group, SVA was correlated with TPA, TPA was correlated with LL, PI, PT, and SS, and PT was correlated with PI and SS(P<0.05). TK, SVA, PI, SS, TPA and LL were significantly correlated with AVCF after PKP in OVCF patients(P<0.05). After adjustment of age, initial fracture site, vertebral height recovery rate, diabetes, number of fractured vertebrae before operation, bone density, amount of bone cement, and leakage of bone cement into intervertebral disc, SVA(OR=2.633, 95%CI: 1.857-3.732), TPA(OR=2.497, 95%CI: 1.684-3.702), TK(OR=3.184, 95%CI: 2.699-3.755), LL(OR=0.526, 95%CI: 0.438-0.631), PI(OR=0.478, 95%CI: 0.320-0.715), and SS(OR=0.592, 95% CI: 0.500-0.701) were still significantly correlated with AVCF(P<0.001). SVA, TPA, TK, LL, PI, and SS all had certain predictive values for postoperative AVCF in OVCF patients after PKP[area under the curve(AUC)>0.750]. Among them, SVA had a bigger AUC value(0.826) for predicting AVCF than other parameters, with a sensitivity of 0.827, specificity of 0.757, and accuracy of 0.792. Conclusions: There is a significant correlation between AVCF and spinopelvic sagittal balance in OVCF patients after PKP surgery. SVA, TPA, TK, LL, SS, and PI have certain predictive values for the occurrence of AVCF after PKP; Smaller SVA, TPA, TK and larger LL, SS, PI at 3 months after surgery can reduce the probability of AVCF occurrence in OVCF patients after PKP surgery.