Safety and efficacy of decompressed vertebroplasty in reducing pulmonary fat embolism: a proof-of-mechanism study in a sheep model.

BACKGROUND

Percutaneous vertebroplasty (PV) is a minimally invasive procedure for vertebral compression fractures. However, elevated intravertebral pressure during bone cement injection may increase the risk of pulmonary fat embolism (PFE). To address this issue, a decompressed vertebroplasty technique is introduced by incorporating a contralateral aspiration to establish a pressure gradient inside the vertebral body to guide cement flow. Such a mechanism can facilitate the removal of fat droplets. This study, therefore, assesses the effect of decompression PV on pulmonary fat droplet burden to evaluate its preliminary proof-of-mechanism potential.

METHODS

Eight skeletally mature male Corriedale sheep (Ovis aries) were randomly allocated into 2 experimental groups (n = 4 per group). Bilateral PV was performed at 3 nonadjacent lumbar vertebral levels in each animal. Group A (control) received conventional PV procedures with 0.8 mL of polymethylmethacrylate (PMMA) cement injected per vertebral body. Group B (treatment) underwent decompressed vertebroplasty, consisting of simultaneous 1.2 mL PMMA injection through the primary trocar while maintaining continuous -600 mmHg suction via the contralateral access cannula. Following a 7-day postoperative observation period, all subjects were euthanized, spinal cord and lung tissues were harvested. Spinal nerve sections were stained with Luxol Fast Blue (LFB) and Fluorojade C (FJC) for nerve damage assessment, while lung tissues were stained with osmium tetroxide (OsO₄) to detect fat droplets.

RESULTS

CT analysis demonstrated that lung tissues in group B had significantly fewer OsO₄-positive fat droplets than those in group A (p = .034). This difference occurred despite comparable cement distribution between groups (Group A: 0.59 ± 0.33 mL, Group B: 0.71 ± 0.45 mL, p = .42) and no significant difference in cement extravasation rates. Histopathological evaluation revealed no spinal cord damage.

CONCLUSIONS

In a healthy ovine model, decompressed vertebroplasty demonstrated preliminary proof-of-mechanism potential in reducing histological pulmonary fat droplet burden under the applied negative pressure gradient. However, further studies are required to determine whether these surrogate findings translate into a reduction in clinically meaningful embolic events or confirmed procedural safety in a clinical setting.