Motion in lumbar functional spine units during side bending and axial rotation moments depending on the degree of degeneration.
METHODS
Human lumbar spine specimens were tested in axial rotation and side bending. Motion was related to the grade of degeneration.


OBJECTIVE
To determine the degree to which degeneration with fissure formation in the disc affects axial rotation of the lumbar functional spine unit.


BACKGROUND
There is controversy in the literature regarding the influence of severe degeneration and fissures of the disc on the range of axial rotation.


METHODS
Thirty-six lumbar spine specimens were tested in axial rotation and side bending, by applying pure moments in an unconstrained setting. The motion in 6 df was recorded by dial gauges. The grade of degeneration was established by the grading schemes of Nachemson, Thompson, Adams, and Mimura.


RESULTS
A significant increase of axial rotation and lateral translation under torque was found. This increase mainly took place between Grade 3 according to the schemes of Nachemson, Thompson, and Adams (no fissure formation) and the higher grades of degeneration (defined by fissure formation). Reduced disc height was always associated with fissures.


CONCLUSIONS
A reduced lumbar disc height in radiographs seems to be associated with fissure formation in the disc. In this case, the range axial rotation after torque is increased in comparison with cases with less degeneration.
Krismer
M
M
Department of Orthopaedics and the Laboratory of Biomechanics, University of Innsbruck, Austria. martin.krismer@uibk.ac.at
Haid
C
C
Behensky
H
H
Kapfinger
P
P
Landauer
F
F
Rachbauer
F
F
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation