STUDY DESIGN: Morphometric analysis of anatomic scoliotic specimens. OBJECTIVE: The objective of this study was to identify a typical deformation pattern for thoracic and lumbar vertebrae in idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Idiopathic scoliosis is a three-dimensional 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 deformities. MATERIALS AND METHODS: Thirty scoliotic specimens from two major osteologic sources were studied using a three-dimensional digitizing protocol developed by our research group creating a precise three-dimensional reconstruction of the vertebrae. Parameters were then calculated for each vertebra from these reconstructions. Every scoliotic specimen was then matched with a normal specimen to provide for a representative control group. RESULTS: A total of 984 vertebrae (472 scoliotic and 512 normal vertebrae) were measured, creating the largest database of normal and scoliotic vertebral specimens. A characteristic deformity pattern was identified consisting of progressive vertebral wedging, decreased pedicle width on the concave side of the curve, and articular facet surface varying greatly with all findings increasingly more important toward the apex of the curve and as curve severity increased. 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.
STUDY DESIGN: Morphometric analysis of anatomic scoliotic specimens. OBJECTIVE: The objective of this study was to identify a typical deformation pattern for thoracic and lumbar vertebrae in idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Idiopathic scoliosis is a three-dimensional 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 deformities. MATERIALS AND METHODS: Thirty scoliotic specimens from two major osteologic sources were studied using a three-dimensional digitizing protocol developed by our research group creating a precise three-dimensional reconstruction of the vertebrae. Parameters were then calculated for each vertebra from these reconstructions. Every scoliotic specimen was then matched with a normal specimen to provide for a representative control group. RESULTS: A total of 984 vertebrae (472 scoliotic and 512 normal vertebrae) were measured, creating the largest database of normal and scoliotic vertebral specimens. A characteristic deformity pattern was identified consisting of progressive vertebral wedging, decreased pedicle width on the concave side of the curve, and articular facet surface varying greatly with all findings increasingly more important toward the apex of the curve and as curve severity increased. 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.