Intervertebral foramen narrowing during vertical dynamic loading

Abstract

Objective: The goal of the present study was to examine the effect of vertebral body fracture on the InterVertebral Foraminal IVF parameters with an input acceleration to the seat bottom in the inferior-to-superior direction.

Methods: A series of 43 isolated lumbar spines underwent vertical dynamic loading using the vertical accelerative device to determine the influence of inferior to superior loading through the lumbar spine on the intervertebral foramen (IVF) geometries. Existence of foraminal stenosis was quantified using pre- and post-test computed tomography (CT) images. Foraminal height (IVF_Ht) and posterior disk height (PD_Ht) were the key IVF parameters.

Results: There was a significant (p < 0.05) decrease in the post-test IVF measurements compared to the pretest measurements. Furthermore, 30% of the total 49 AIS 2 cases and 70% of the total 21 AIS 3 cases had IVF values below the literature reported thresholds for IVF_Ht of < 15 mm and PD_Ht of < 4 mm, indicating likely occurrence of foraminal stenosis.

Conclusions: These results underscore the need to assess foraminal geometry in compression fractures of the lumbar spine from vertical dynamic loading.

Keywords: Thoracolumbar fractures; intervertebral foramen; lumbar radiculopathy.