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Published on: September 16, 2022
Occipital Condyle-C1 Complex Screw for Fixation of Basilar Invagination Patients with Atlas Assimilation
Huaiyu Tong1, Lianfeng Li, Xin-Guang Yu
1Chinese PLA General Hospital, Department of Neurosurgery, Haidian District, Beijing 100853, China.
Aim:
To investigate whether C1-occipital condyle complex (CC complex) screws can be safely and rapidly placed without guidance in basilar invagination patients with atlas assimilation.
Material And Methods:
The occipital-cervical (OC) junction was fixed posteriorly in 8 basilar invagination patients with atlas assimilation using polyaxial titanium screws inserted unicortically into the CC complex and C2 pedicles and subsequent fixation to a 3-mm rod. Anatomic landmarks were used during the drilling. The screw angles and lengths of the CC complex were analyzed.
Results:
The width, length, and height values of the left-side CC complex were 7.96±2.23, 16.06±2.73, and 13.76±2.06 mm; those of the right-side CC complex were 7.84±1.38, 16.66±2.58, and 12.81±2.62 mm. The CC complex entry point was at the central point of posterior surface of the CC complex. The angle used for medialization was 10-15°, which was also the maximal superior screw angulation in the sagittal plane. The screw length required for unicortical purchase was 16-22 mm. The screw was not misplaced or poorly positioned, and no neurovascular complications associated with screw insertion were detected.
Conclusion:
In patients with atlas assimilation, CC complex screws can be placed safely. The CC complex screws can be safely inserted assisted by microscope without image guidance.
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