Abstract
Background The study aimed to evaluate the safety and feasibility of transpedicular instrumentation
for the C2 vertebra and to establish the precise anatomical parameters and boundaries
within which this procedure can be safely and effectively performed.
Methods This retrospective study analyzed 66 patients who underwent C2 transpedicular screw
fixation. Preoperative and postoperative axial, sagittal, and coronal computed tomography
(CT) scans were examined. Anatomical measurements were taken to determine the horizontal
and vertical distances from the C2 pedicle projection to the vertebral foramen using
CT images. Based on the anatomical location of the vertebral artery within the C2
vertebral foramen, the patients were divided into four subgroups using the horizontal
pedicle width (HPW) and vertical pedicle width (VPW) of the C2 spine.
Results The average age of the patients included in the study was 46.48 years. The patient
population comprised 32 (48.5%) males and 34 (51.5%) females. Based on the anatomical
measurements, the distribution of C2 vertebra types was as follows: type 1 accounted
for 68.9%, type 2 for 3.8%, type 3 for 16.7%, and type 4 for 10.6%. Significantly
narrower pedicle widths were observed in types 2 and 4 compared to other vertebra
types. Type 2 had the largest medial angle (MA), while type 4 had the narrowest MA.
In terms of the sagittal plane, type 4 exhibited the widest MA and type 3 had the
narrowest MA, but these differences were not statistically significant. Among the
cases, 12 (18.1%) involved the vertebral foramen, with 1 case (8.3%) showing screw-related
vertebral artery injury (0.75% of all screws). No vertebral artery injuries were observed
with the other transpedicular screws.
Conclusion Preoperative anatomical measurements for patients undergoing transpedicular instrumentation
on the C2 vertebra should include planning CT images on three planes: axial, sagittal,
and coronal.
Keywords
C2 vertebra (axis) - transpedicular instrumentation - high-positioned vertebral artery
