Dynamic changes in the dimensions of the lumbar spinal canal: an experimental study in vitro.
The variation in the dimensions of the lumbar spinal canal under both flexion-extension and axial compression-distraction was studied using computerized tomography (CT) scans in human cadaver lumbar spine specimens. In 3-mm-thick CT slices through the disk at L3-L4, the cross-sectional area of the spinal canal was reduced by around 40 mm2, corresponding to a 16% reduction of the initial area when the lumbar spines were moved both from flexion to extension and from distraction to compression. A corresponding reduction in the midsagittal diameter of the canal of 2 mm was found. During these motions, the ligamentum flavum did not appear to be a significant factor for the dynamic changes affecting the dimensions of the canal. This held true even after the disk had been excised in order to produce a total collapse of the disk space.
Schönström
N
N
Department of Orthopaedic Surgery, Sahlgren Hospital, University of Göteborg, Sweden.
Lindahl
S
S
Willén
J
J
Hansson
T
T
D006801:Humans; D066298:In Vitro Techniques; D007403:Intervertebral Disc / Q000000981:diagnostic imaging; D008161:Lumbosacral Region; D009068:Movement; D013115:Spinal Canal / Q000000981:diagnostic imaging* / Q000502:physiology; D014057:Tomography, X-Ray Computed