The effects of biomechanical factors on adjacent vertebral compression fractures after percutaneous kyphoplasty: a propensity score matching analysis

Adjacent vertebral compression fracture (AVCF) is the primary factor affecting satisfaction after PKP surgery. In addition to osteoporosis, certain structural characteristics of the vertebral body itself also increase their risk. The purpose of this study was to explore the impact of biomechanical changes on AVCF after balancing other factors.As a routine treatment of OVCF, the postoperative refracture of PKP is a serious problem. The aim of our study was to explore the impact of lumbar biomechanical changes on the risk of AVCF. A propensity score matching was performed to balance the interference of osteoporosis, which is the primary risk factor of AVCF.A retrospective, single-center case-control study was performed. From September 2013 to March 2020, 1752 patients were enrolled, and AVCF was assessed in 80 of these patients. A propensity score matching (PSM) analysis was performed, and 5 potential confounding factors were matched (age, BMI, number of fractured vertebral bodies, fracture region, and HDL). The preoperative and postoperative radiological factors were measured in the matched cohort of 48 pairs. A conditional logistic regression analysis to adjust the comparative risks.The preoperative wedge angle and its postoperative recovery of the AVCF group were significantly higher than that of the non-AVCF group. The local kyphosis of the fractured vertebral body between the two groups was similar, but the recovery in the AVCF group was slightly higher than that in the non-AVCF group. The preoperative and postoperative relative anterior height (RAH) of the fractured vertebral body was familiar in two groups, so was the recovery of RAH. The preoperative spino-sacral angle (SSA) was significantly higher in the AVCF group than in the non-AVCF group. The preoperative wedge angle was identified as the only significant risk factor for AVCF in the multivariate analysis.In conclusion, a larger preoperative fracture vertebral wedge angle is a risk factor for AVCF. For such high-risk patients, surgeons should be cautious about surgical decisions. The postoperative active measures and tailored surveillance should be attached to great importance as well.