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Authors (on behalf of the AOSpine Knowledge Forum Tumor)

Nicolas Dea, Jeremy Reynolds

General Editor

Luiz Vialle

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C2 pars screw insertion

1. C2 pedicle vs. pars screw

When only a C1–C2 arthrodesis is done, we prefer to use a C2 pedicle screw over a C2 pars screw. This is because the pars screw starting hole is more distal and therefore requires more muscle dissection. But, if a C2 pedicle screw is not possible, then we place a C2 pars screw.

C2 pedicle vs. pars screw

2. Preoperative evaluation

A preoperative CT image must be evaluated to determine if this screw is possible. Some patients have a pars that is too small to accept such a screw.

3. Screw entry point

The starting point of the C2 pars screw is 3–4 mm cranial to the C2–C3 facet joint and in the midpoint of the pars mediolaterally.

Place a small burr hole as the starting point for the transarticular screw.

C2 pars screw entry point

4. Screw trajectory

The trajectory is as dorsal as possible without perforating the dorsal cortex of the C2 pars. This is essentially a short transarticular screw.

C2 pars screw trajectory

5. Screw insertion

Tap, measure the length, and place the screw. Typically a unicortical screw that is longer than 16 mm is adequate.

C2 pars screw insertion
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