TY - JOUR
T1 - Anatomical considerations for subaxial (C2) pedicle screw placement
T2 - A radiographic study with computed tomography in 93 patients
AU - Smith, Zachary A.
AU - Bistazzoni, Simona
AU - Onibokun, Adebukoa
AU - Chen, Nan Fu
AU - Sassi, Marco
AU - Khoo, Larry T.
PY - 2010/5
Y1 - 2010/5
N2 - Study Design: Radiographic study. Objective: More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial computed tomography. BACKGROUND DATA: Although earlier studies have analyzed the anatomy of the C2 pars interarticularis, little attention has been focused on the dimensions of the C2 pedicle. Methods: Ninety-three patients (47 males, 46 females; mean age 48.4y) who had previous cervical spinal computed tomography imaging were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, ie, the angle between the pedicle axis and the midline of the vertebral body). Results: The overall mean pedicle width was 5.8±1.2mm. The mean pedicle width in male patients (6.0±1.3mm) was greater than that in the female patients (5.6±1.1mm). This difference was not found to be statistically significant (P=0.679). The overall mean PTA was 43.9±3.9 degrees. The mean PTA in male patients was 43.2±3.8 degrees, whereas that in female patients was 44.7±3.7 degrees. Conclusions: Given the significant variability in pedicle widths and the need for precise trajectory planning in pedicle cannulation, preoperative planning is absolutely mandatory. A significant percentage of patients have pedicle widths that may not accommodate screw fixation. In addition, the angle of entry into the C2 pedicle must be carefully measured for safe instrumentation at this level.
AB - Study Design: Radiographic study. Objective: More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial computed tomography. BACKGROUND DATA: Although earlier studies have analyzed the anatomy of the C2 pars interarticularis, little attention has been focused on the dimensions of the C2 pedicle. Methods: Ninety-three patients (47 males, 46 females; mean age 48.4y) who had previous cervical spinal computed tomography imaging were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, ie, the angle between the pedicle axis and the midline of the vertebral body). Results: The overall mean pedicle width was 5.8±1.2mm. The mean pedicle width in male patients (6.0±1.3mm) was greater than that in the female patients (5.6±1.1mm). This difference was not found to be statistically significant (P=0.679). The overall mean PTA was 43.9±3.9 degrees. The mean PTA in male patients was 43.2±3.8 degrees, whereas that in female patients was 44.7±3.7 degrees. Conclusions: Given the significant variability in pedicle widths and the need for precise trajectory planning in pedicle cannulation, preoperative planning is absolutely mandatory. A significant percentage of patients have pedicle widths that may not accommodate screw fixation. In addition, the angle of entry into the C2 pedicle must be carefully measured for safe instrumentation at this level.
KW - Axis
KW - C2
KW - Computed tomography
KW - Pedicle
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U2 - 10.1097/BSD.0b013e3181b40234
DO - 10.1097/BSD.0b013e3181b40234
M3 - Article
C2 - 20414136
AN - SCOPUS:77952115827
VL - 23
SP - 176
EP - 179
JO - Journal of Spinal Disorders
JF - Journal of Spinal Disorders
SN - 1536-0652
IS - 3
ER -