Outcomes and safety of vertebral augmentation with expandable intravertebral implants for osteoporotic vertebral fractures: a retrospective cohort study with subgroup analysis on type OF4 fractures

The main objective of the study is to evaluate the outcomes and safety of using vertebral augmentation (VA) with expandable intravertebral implants (EIIs) for osteoporotic vertebral fractures, with subgroup analysis on type OF4 osteoporotic vertebral fractures. A retrospective cohort study was conducted at a tertiary medical center from January 2017 to December 2021. Seventy-five patients (mean age 72.3 ± 7.4 years; 22.7% male) with single-level osteoporotic vertebral fractures (OVFs) who had undergone vertebral augmentation with expandable intravertebral implants were included, and the mean follow-up was 36.7 ± 19.1 months. For clinical outcomes, we evaluated the visual analog scale (VAS) for pain scale, Oswestry Disability Index (ODI) for functional outcomes, and occurrences of complications. Key radiological parameters including anterior vertebral height compression ratio (AVH CR), middle vertebral height compression ratio (MVH CR), local kyphotic angle (LKA), regional kyphotic angle (RKA), local coronal angle (LCA) and Cobb’s angle (CBA), were collected and compared. Multivariate logistic regression was used to identify risk factors for complications. Patients classified as type OF4 fracture (n = 45) were selected for further subgroup analysis. All population as well as OF4 group demonstrated significant clinical improvements in the VAS pain score (P < 0.0001) and ODI functional score (P < 0.0001) postoperatively. Most radiological parameters also improved significantly in all patients and OF4 group, including anterior vertebral height compression ratio (P < 0.0001), middle vertebral height compression ratio (P < 0.0001), local kyphotic angle (P < 0.0001), and regional kyphotic angle (P < 0.0001). For complications, adjacent level fractures happened in 26.7% of patients; cement leakage happened in 40% of patients, and bone cement dislodgement happened in 22.7% of patients. Re-operation rate was low (4%). Body mass index (BMI) (P = 0.032) and age (P = 0.003) were identified as potential risk factors for adjacent level fractures. Preoperative anterior vertebral height compression ratio (P = 0.011) was risk factor for cement leakage. BMI (P = 0.008), osteoporosis (P = 0.023), and preoperative middle vertebral height compression ratio (P = 0.028) were risk factors for bone cement dislodgement. Vertebral augmentation with expandable intravertebral implant appears to be a viable alternative for elderly patients with type OF4 osteoporotic vertebral fractures. It offers comparable efficacy in pain relief and functional improvement, with few severe complications making it suitable for those who may not tolerate invasive surgeries. This study is retrospectively registered.