In Vivo Dynamic Changes of Dimensions in the Lumbar Intervertebral Foramen

Abstract

BACKGROUND CONTEXT-Previous studies have reported position-dependent changes of the lumbar intervertebral foramen (LIVF) dimensions at different static flexion-extension postures. However, the changes of the LIVF dimensions during dynamic body motion have not been reported. PURPOSE-The objective of this study was to investigate the in-vivo dimensions of the LIVF during a dynamic weight-lifting activity. STUDY DESIGN/SETTING-A retrospective study. METHODS-Ten asymptomatic subjects were recruited for this study. 3D vertebral models of the lumbar segments from L2 to S1 were constructed for each subject using MR images. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a dynamic weight-lifting activity from an upper body position of 45° to a maximal extension position. The in-vivo positions of the vertebrae along the motion path were reproduced using the 3D vertebral models and the fluoroscopic images. The minimal area, height, and width of each LIVF during the dynamic body motion were analyzed. RESULTS-The LIVF area and width monotonically decreased with lumbar extension at all levels except L5-S1 (p < 0.05). On average, the LIVF area decreased by 7.4 ± 6.7 %,