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Pipsa Ylanko, AOSpine Global Education Manager

General Editor: Luiz Vialle

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

Occipitocervical trauma - C1-C2, Rotatory subluxation Anterior C1-C2 fusion

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Glossary

1 Introduction top

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The advantage of the anterior transarticular screw is that it requires less muscle dissection than a posterior trans articular screw.


Check of feasibility

As with all screws that are placed at the C1 and C2 levels, a preoperative CT scan must be obtained to determine the feasibility of this screw.

2 Reduction top

Reduction may be performed by gentle traction, especially in acute cases. If not achieved or in more delayed cases, surgical reduction is indicated.

This involves soft tissue release (ligaments, capsules and scar tissues found in delayed presentation) followed by gentle manipulation.

The final reduction must be confirmed using a C-arm.

3 Trans articular screw insertion top

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Approach for screw insertion

A standard Smith Robinson approach to the cervical spine is utilized. The skin incision is made just below the mandible.

Careful blunt dissection is performed under magnification. The digastric muscle is encountered, as may the hypoglossal and superior laryngeal nerves.These are retracted rostrally to expose the C1-2 joint.


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Screw entry point

The starting hole for the screw is 7-8 mm distal to the C1-C2 joint. It is 3-5 mm lateral to the medial boarder of the C1-C2 joint.


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Screw trajectory

It is directed approximately 30° laterally and 30° posteriorly across the joint.


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Drill, tap, measure and insert the screw under fluoroscopic guidance. The screw should not perforate the dorsal cortex of C1, nor should it violate the occipital cervical joint.

4 Anterior fusion of the C1-C2 joint top

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The joint is decorticated and packed with cancellous bone graft.

v1.0 2016.12.01