Predictors of adjacent level fractures following kyphoplasty for vertebral compression fractures of all etiologies: A retrospective cohort study.

background and purposeAdjacent-level fracture (ALF) is frequently observed following vertebral augmentation, although recent evidence suggests it is largely a disease-related event rather than a consequence of the procedure itself. Existing data derive almost exclusively from osteoporotic fractures treated with vertebroplasty. We sought to identify predictors of ALF after kyphoplasty for vertebral compression fractures (VCFs) of all etiologies. MATERIALS AND

methodsThis retrospective, single-center cohort study included adults undergoing first-time kyphoplasty for VCFs between 2015 and 2025 with pre-procedural imaging and at least one post-procedural follow-up imaging study. Fracture mechanism was dichotomized as atraumatic (spontaneous or pathological) versus traumatic (fall or trauma). The primary outcome was radiologically confirmed new fracture immediately adjacent to an augmented level. Time to ALF was analyzed with Cox proportional-hazards regression; univariably significant variables were entered into a multivariable model.

resultsAmong 192 patients (median age, 71 years; 143 women [74.5%]), ALF occurred in 39 (20.3%) at a median of 125 days. Cumulative incidence was 16.7% at 180 days and 26.6% at 1 year. Factors independently associated with ALF were atraumatic mechanism (adjusted HR, 3.63; 95% CI, 1.82-7.23; P < 0.001), older age (adjusted HR, 1.26 per 5 years; 95% CI, 1.03-1.55; P = 0.027); a longer fracture-to-augmentation interval was protective (adjusted HR, 0.82 per 30 days; 95% CI, 0.68-0.99; P = 0.038). Multilevel augmentation was associated with ALF on univariable analysis (HR, 2.73; 95% CI, 1.42-5.24; P = 0.003). New fractures involved a cranial level in 22 patients (56.4%), a caudal level in 13 (33.3%) and both cranial and caudal levels in 4 (10.3%). Cement type, thoracolumbar junction involvement, bisphosphonate use, documented osteoporosis, and index fracture severity were not associated with ALF.

conclusionsIn this cohort, older age, atraumatic fracture mechanism, and a shorter interval from fracture diagnosis to augmentation were associated with ALF after kyphoplasty across all VCF mechanisms, and multilevel augmentation was associated with ALF, with the association appearing to emerge predominantly beyond 180 days. These variables plausibly reflect a shared underlying burden of skeletal compromise. Given substantial loss to follow-up and limited follow-up duration, these associations require confirmation in prospective cohorts but may help identify patients who could benefit from closer clinical follow-up and increased awareness of subsequent fracture risk.