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Pipsa Ylanko, AOSpine Global Education Manager

General Editor: Luiz Vialle

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

Occipitocervical trauma - ATLAS, Type IIIb C1 lateral masses osteosynthesis

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1 Introduction top


ATLAS osteosynthesis may be performed for type 3b fractures.

In order to avoid joint fusion C1-C2 or C0-C2 a direct approach can be performed stabilizing the lateral masses.

2 Screw insertion top


Lateral mass screws are inserted bilaterally according to standard procedure.

The lateral masses may be more mobile than in an intact arch. The use of clamps or other types of support may be necessary the prevent movement of the lateral mass during screw insertion.

3 Reduction top


The screw extensions are used as joysticks to reduce the fracture.


Once satisfactory reduction is achieved, a connecting rod is installed between the screws to secure the reduction.


Slight compression is applied to ensure anatomical reduction.

4 Fixation top


Screws are tightened to secure the reduction.

v1.0 2016.12.01