THE INFLUENCE OF EPIDURAL PRESSURE ON REMODELLING OF THORACOLUMBAR BURST FRACTURES

Abstract

Introduction and Aims: Speculation exists with regard to the exact mechanism of remodelling of thoracolumbar burst fractures treated non-operatively. We prospectively evaluated spinal canal remodelling in 30 patients with burst fractures by measuring the epidural pressure following ethical approval.

Method: Thirty-four patients (average age 37 years) were recruited into the study. The injury followed a fall from a height in 18 patients; and 12 resulted from a road traffic accident. All patients were neurologically intact. Plain X-rays and CT scans were obtained to evaluate the injuries. The patients were treated non-operatively with orthoses. At two weeks and 12 months post-injury epidural pressures were measured in theatre. The measurements were performed in the lateral decubitis position, and a fluoroscopically guided radio-opaque catheter was positioned below the fracture site to record the epidural pressure.

Results: Thirty patients were included in the study and four were excluded due to inadequate follow-up. The average progress in the Cobb’s angle at one-year follow-up was 2.690 (range 10–60). At the time of injury the mean canal compromise measured on CT scans was 43% (range 32%–83%) and at follow-up had improved to 28% (range 44%–100%). The CT volumetric measurements showed an average improvement of 10% in volume at follow-up (range 7%–16%).

The average epidural pressure recorded at the time of injury was 16.65mmHg (range 2.5–30.85mmHg) and at follow-up was –5.85mmHg (range 0 to –10.17mmHg). There were no complications following epidural pressure monitoring.

Conclusion: Scapinelli and Candiotti hypothesised that burst fractures remodelled secondary to respiratory oscillations transmitted to the epidural space. The raised epidural pressure (p< 0.001), by virtue of its mechanical effect, may be one of the factors responsible for the remodelling of burst fractures.