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Abstract from the SRS 2001 Annual Meeting
Stefan Parent, M.D.1
Hubert Labelle, M.D.1
Wafa Skalli, Ph.D.2
Bruce Latimer, Ph.D.3
Jacques de Guise, Ph.D.4 1Hôpital Ste-Justine, Montreal, QC, Canada
2École Nationale
Supérieure d'Arts et Métiers, Paris, France
3Cleveland Museum of Natural History,
Cleveland, OH, USA
4École de Technologie Supérieure, Montreal, QC, Canada PURPOSE:
Idiopathic scoliosis is a 3-D deformity affecting the orientation and position
of the spine in space. The regional deformity has been studied extensively but
most of the knowledge we currently have regarding the local deformity is the result
of isolated observations made on rare scoliotic specimens with severe scoliotic
deformities. OBJECTIVE:
The objective of this study was to identify a typical
deformation pattern for thoracic and lumbar vertebrae in idiopathic scoliosis.
MATERIAL AND METHOD:
Thirty scoliotic specimens were studied using a 3-D digitizing
protocol developed by our research group using a 3-D digitizer (Fastrack, Polhemus,
Vermont, USA) creating a precise 3-D reconstruction of the vertebrae. Fifteen
scoliotic specimens were identified from the Hamann-Todd Osteological Collection
in Cleveland and 15 were identified from the Terry Osteological Collection in
Washington. We then matched every scoliotic specimen with a normal specimen based
on age, sex, race, weight and height to provide for a representative control group.
RESULTS:
We measured a total of 984 vertebrae (472 scoliotic and 512 normal vertebrae)
by recording the 3-D coordinates of 200 points each representing a specific anatomical
landmark, creating the largest database of normal and scoliotic vertebral specimens.
Parameters (134) were then calculated for each vertebra from these sets of points.
One-way and two-way ANOVA calculations were done on scoliotic and normal parameters
to determine a statistically significant deformation pattern. A characteristic
deformity pattern was identified consisting of progressive vertebral wedging,
decreased pedicle width on the concave side of the curve and articular facets
surface varying greatly with all findings increasingly more important towards
the apex of the curve and as curve severity increased. A relation between vertebral
wedging and pedicle width on the concave side of the curve was also identified.
Spinous process orientation was variable. All findings were statistically significant
with p < 0.05. CONCLUSION:
These results are of critical importance for the understanding
of the local and regional deformity and in understanding curve progression. Our
results also advocate caution in the use of pedicle screws in the thoracic spine
especially on the concave side of the curve. With this deformation pattern available,
it should be possible to predict the 3-D local vertebral deformity of any scoliotic
curve based on simple PA and Lat radiographs of adolescents with idiopathic scoliosis.
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