General Editor: Luiz Vialle

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

Occipitocervical trauma - Traumatic spondylolisthesis, Levine IIa Direct osteosynthesis of the isthmus

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Glossary

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

1 Introduction top

A careful evaluation of the fracture pattern is essential for this procedure. IF the fracture does not run through the inter-articular portion of the C2 the screw trajectory will need to be modified.

2 Reduction top

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Reduction is performed under image intensifier. Extension or flexion is applied depending on the position of the fragments. Reduction should not include traction maneuvers.


A short K-wire may be inserted bilaterally to temporarily hold the reduction. Great care has to be taken during this insertion not to damage the surrounding structure. The K-wire will typically not need to be inserted further than 1 cm.

3 Fixation top

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The typical osteosynthesis is performed according to the technique of C2 pedicle screws, however they are inserted as lag screws.


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Screw entry point

The pedicle screw starts more cranially than the pars screw and it is directed medially.

To find the starting point for the pedicle screw, draw a line along the cranial leading edge of the C2 lamina (1).

Then, draw a line along the midpoint of the pars mediolaterally (2) (see illustration).


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Drilling

Burr a starting-hole 2 mm lateral to the intersection of line 1 and line 2.


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Remove one K-wire and use either a pedicle probe or a handheld drill in an oscillating mode to drill the hole for the pedicle screw.

The direction of the drill is approximately 30° – 45° medial and craniocaudally angled to the bottom half of the tubercle of C1.


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Screw insertion

Tap, measure the length, and place a 3.5 mm cortex screw or lag screw. Screw length is typically between 25 and 35 mm.

The procedure is then repeated on the contralateral side.

v1.0 2016.12.01