Objective: Recompression of augmented vertebrae (RCAV) is often seen after percutaneous kyphoplasty (PKP), especially at the thoracolumbar junction. The authors aimed to develop and validate a risk prediction model (nomogram) for RCAV and to evaluate the efficacy of a modified puncture technique for RCAV prevention after PKP for thoracolumbar osteoporotic vertebral fractures (OVFs).
Methods: Patients who underwent PKP for single thoracolumbar OVFs (T10-L2) between January 2016 and October 2020 were reviewed and followed up for at least 2 years. All patients were randomly divided into a training group (70%) and a validation group (30%). Relevant potential data affecting recompression were collected. Predictors were screened by using binary logistic regression analysis to construct the nomogram. Calibration and receiver operating characteristic curves were used to evaluate the consistency of the prediction models. Finally, the efficacy of the modified puncture technique for prevention of RCAV in OVF patients with a preoperative intravertebral cleft (IVC) was further demonstrated through binary logistic regression analysis.
Results: Overall, 394 patients were included and 116 of them (29.4%) sustained RCAV. The independent risk factors included decreased bone mineral density, lower level of serum 25-hydroxy vitamin D3, larger C7-S1 sagittal vertical axis (SVA), preoperative IVC, and solid-lump cement distribution. The area under the curve (AUC) of the prediction model was 0.824 in the training group and 0.875 in the validation group patients. The calibration curve indicated the predictive power of this nomogram, with the preoperative IVC having the highest prediction accuracy (AUC 0.705). The modified puncture technique significantly reduced the incidence of RCAV by enhancing bone cement distribution into a sufficiently diffused distribution in OVF patients with preoperative IVC.
Conclusions: The nomogram prediction model had satisfactory accuracy and clinical utility for identification of patients at low and high risk of postoperative RCAV. Patients at high risk of postoperative RCAV might benefit from the target puncture technique and vitamin D supplementation as well as effective antiosteoporotic therapies.
Keywords: lumbar; nomogram; osteoporotic vertebral fractures; percutaneous kyphoplasty; recompression of augmented vertebrae; thoracic; thoracolumbar junction.