Paraspinal Muscle Fat Infiltration Predicts Vertebral Refracture After Kyphoplasty: Development and Validation of a Novel Nomogram Model.

BACKGROUND

Vertebral refracture following percutaneous kyphoplasty (PKP) remains a significant challenge in managing osteoporotic vertebral compression fractures. This study aimed to develop and validate a novel nomogram model integrating paraspinal muscle fat infiltration (FI), bone mineral density (BMD), and vertebral parameters to predict refracture risk post-PKP.

METHODS

A retrospective cohort of 150 osteoporotic vertebral compression fracture patients undergoing PKP was analyzed. Paraspinal FI was quantified via preoperative magnetic resonance imaging, and BMD was measured using dual-energy X-ray absorptiometry. Refracture was defined as recurrent or adjacent vertebral fractures within 1 year post-PKP. Multivariate logistic regression identified predictors, and a nomogram was constructed. Discriminative performance was assessed using the area under the receiver operating characteristic curve.

RESULTS

Refracture occurred in 16 patients (10.7%). Multivariate analysis identified FI ≥25% at the fractured vertebra as the strongest independent predictor (odds ratio = 14.24, 95% confidence interval: 1.57-129.02, P = 0.018). The nomogram, incorporating FI, BMD, and vertebral parameters, demonstrated excellent discrimination (area under the curve = 0.88, 95% confidence interval: 0.82-0.94) and calibration. FI exhibited an inverse correlation with lumbar and femoral neck BMD (P < 0.01), highlighting synergistic muscle-bone deterioration.

CONCLUSIONS

Paraspinal FI is a critical biomarker for post-PKP refracture risk. The nomogram model provides a practical tool for personalized risk stratification, emphasizing the integration of muscle quality assessment into spinal fragility management.