The effect of anterior osteophytes and flexural position on thoracic trabecular strain.
METHODS
Compressive and shear trabecular strains were evaluated using six cadaveric thoracic spines that included anterior osteophytes. The treatments were divided into three groups: 1) osteophytes intact and the specimen in the neutral position, 2) osteophytes removed and the specimen in the neutral position, and 3) osteophytes removed and the specimen with 5 degrees of additional flexion.


OBJECTIVE
To investigate the influence of osteophytes and flexural position on vertebral trabecular strain during axial compression.


BACKGROUND
In the thoracic spine, the incidence of anterior wedge fractures increases with the severity of kyphosis. It is unclear whether the role of anterior osteophytes in the thoracic spine is to restrict progressive kyphosis, conduct axial load anteriorly, or both.


METHODS
Thoracic motion segments, T10-T12, were axially loaded in compression, and the minimum principal and maximum shear strains were measured using texture correlation.


RESULTS
No dramatic changes were found in the spatial distribution of the strains following removal of the anterior osteophytes. Conversely, after removal of the osteophytes and orienting the specimen in 5 degrees of additional flexion, the strain distribution shifted anteriorly and the magnitude increased.


CONCLUSIONS
This study demonstrated that osteophytes seem to restrict progressive kyphosis rather than conduct axial load anteriorly.
Toh
E
E
Department of Orthopaedic Surgery, Tokai University School of Medicine, Kangawa, Japan. eiren@is.icc.u-tokai.ac.jp
Yerby
S A
SA
Bay
B K
BK
McLain
R F
RF
Benson
D R
DR
Mochida
J
J
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D019245:Compressive Strength / Q000502:physiology; D005260:Female; D006801:Humans; D007738:Kyphosis; D008297:Male; D018583:Pliability; D013128:Spinal Osteophytosis; D013904:Thoracic Vertebrae / Q000502:physiology*