Are Traditional Radiographic Methods Accurate Predictors of Pedicle Morphology?
METHODS
Cadaveric in vitro computed tomography (CT) imaging study.


OBJECTIVE
To examine minimum pedicle diameter from transverse and coronal CT reconstructions of thoracolumbar spine specimens and compare their degree of disparity, if any. Pedicle angulation in coronal and transverse planes was measured and their contribution to the disparity in minimum pedicle diameter was assessed.


BACKGROUND
Spinal minimum pedicle diameter can be obtained from both transverse and coronal CT reconstructions; however, the degree of disparity in these measurements has not been described previously. Angulation of the pedicle in transverse and coronal planes may contribute to a disparity in minimum pedicle diameter acquired from reconstructions. This also has not been described previously. This study examined whether the disparity could be predicted by spinal level, as pedicle angulations vary in both coronal and transverse planes.


METHODS
Five thoracolumbar specimens (T1-L5, age 48-59 yrs, male) were CT scanned utilizing clinical protocols. Minimum pedicle diameters and pedicle angulations were acquired in transverse and coronal reconstructions. Disparities between minimum pedicle diameters were measured and the correlation between this disparity and spinal level was characterized.


RESULTS
A significant difference (P < 0.001) in minimum pedicle diameter existed between measures from coronal and transverse reconstructions. There was a significant correlation (P < 0.001) between the difference in minimal pedicle diameter and the transverse pedicle angle as well as the coronal pedicle angle.


CONCLUSIONS
An overestimation of minimum pedicle diameter in the transverse reconstruction occurs when the coronal pedicle angulation increases, and in the coronal reconstruction when the transverse pedicle angulation increases. Therefore, pedicle angle should be determined using both coronal and transverse reconstructions and utilized to reduce the risk of overestimation of the true pedicle diameter.


METHODS
NA.
Department of Neurosurgery, SUNY Upstate Medical University, Syracuse, NY.
Venita
V
Simpson
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
Brandon
B
Clair
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
Nathaniel R
NR
Ordway
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
Stephen A
SA
Albanese
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
William F
WF
Lavelle
D000328:Adult; D001863:Bone Screws; D002102:Cadaver; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013904:Thoracic Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods