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Differences in fixation strength among constructs of atlantoaxial fixation
Chih-Chang Chang1,2, Wen-Cheng Huang1,2, Tsung-Hsi Tu1,2,3
11Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei.
Journal of Neurosurgery. Spine
|November 29, 2018
Summary
C2 pedicle or pars screws offer high success rates in atlantoaxial fixation. Using translaminar screws, however, significantly reduces fixation success. Pars screws are recommended over translaminar screws for better outcomes.
Area of Science:
- Spine Surgery
- Orthopedic Surgery
- Neurosurgery
- Biomedical Engineering
Background:
- Aberrant vertebral arteries pose risks during C2 screw placement.
- Common C2 screw options include pedicle, pars, and translaminar types.
- Limited in vivo clinical data compares the outcomes of different C2 screw combinations.
Purpose of the Study:
- To evaluate the clinical outcomes of different combinations of C2 screws in posterior atlantoaxial (AA) fixation.
- To compare the success rates of pedicle, pars, and translaminar C2 screws in vivo.
- To determine the optimal C2 screw strategy to avoid jeopardizing the vertebral artery.
Main Methods:
- Retrospective review of consecutive adult patients undergoing posterior AA fixation.
- All patients received bilateral C1 lateral mass screws and two C2 screws (pedicle, pars, or translaminar).
- Patients were grouped by C2 screw combinations for outcome comparison.
Main Results:
- 63 patients were analyzed with a mean follow-up of 34.3 months.
- The highest success rates were observed with 2 C2 pedicle screws (100%) and 2 pars screws (100%).
- Constructs involving translaminar screws showed significantly lower success rates (73.1%) compared to those without (100%).
- Seven patients lost fixation/reduction, all of whom had at least one translaminar screw.
Conclusions:
- C2 pedicle or pars screws, individually or in combination, yield high success rates in AA fixation.
- The inclusion of one or two C2 translaminar screws significantly decreases the success rate of the construct.
- C2 pars screws are recommended over translaminar screws due to superior fixation success rates.
Keywords:
AA = atlantoaxialADI = atlantodental intervalHRVA = high-riding VATAS = transarticular screwVA = vertebral arteryatlantoaxial fixationcervicalpars screwpedicle screwtranslaminar screwMore Related Videos
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