General Editor: Luiz Vialle

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

Occipitocervical trauma - C2, Body fracture Posterior fixation

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Glossary

Authors: Ronald Lehman, Daniel Riew, Klaus Schnake

1 Introduction top

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The three main techniques are:

  • C1-C2 stabilization according to Goel-Harms
  • C1-C2 trans articular screw fixation according to Magerl
  • C1-C3 stabilization

All techniques can be combined with spondylodesis (fusion).

The choice between these techniques will mainly depend on the following factors:

  • Local anatomy
  • Nature of the injury
  • Patient factors
  • Surgical skills

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Local anatomy

The trans articular screw is not indicated in patients with high riding vertebral artery.


Nature of the injury

Adequate screw purchase may not be achievable due to the fracture morphology for either of the screws.

Typically, if trans articular screws cannot be used, the Goel-Harms technique will be possible, and vice versa.

Trans-articular screws are not indicated if the fracture cannot be reduced anatomically.

With associated C1-C2 fractures, eg dislocated C1 burst fractures, the Goel-Harms technique may not be indicated.

C1-C3 Stabilization is indicated if the C2-C3 disk is damaged.


Surgical skills

The choice of procedure will also depend on the surgeons familiarities with the techniques.


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Patient factors

In young patients the Goel-Harms technique is favorable as the implants can be removed after fracture healing. The Magerl procedure on the other hand will damage the C1-C2 joint.

The Magerl procedure may prove difficult or impossible in patients with hyper kyphosis.


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Reduction

Prior to the surgical access the fracture should be reduced anatomically.

Anatomical reduction is essential for the success of the trans articular C1-C2 screw fixation. If this is not possible, the Goel-Harms technique should be used.

Reduction can be performed

  • using halo traction preoperatively
  • intraoperatively using Mayfield clamp or a similar tool
  • by pushing directly on the anteriorly displaced C1/2 segment through the mouth with the index finger in the case of a persistent anterior displacement.

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Approach

Prior to draping the patient for insertion of trans articular screws the location of the skin incision needs to be determined. This is done by placing a long K-wire along the side of the neck in the intended direction of the screw and

viewing on the image intensifier.


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Fixation

One of the following techniques is chosen:

  • C1-C2 trans articular screw fixation according to Magerl
  • C1-C2 stabilization according to Goel-Harms
  • C1-C3 stabilization

2 Posterior internal fixation top

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C1 Screw placement

C1 can be fixed using either lateral mass screws that start just caudal to the posterior arch or that start on top of the posterior arch and then capture the lateral mass. The latter can only be used if the posterior arch is thick enough to allow for the screw.


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C2 screw placement

C2 can be fixed using either of the three techniques:


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Be aware that some posterior arches have a ponticulus posticus that appears to be a thick posterior arch, but in fact is a small bridge of bone that overlies the vertebral artery.


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C3 screw placement

C3 can be fixed using lateral mass screws.


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Rod placement

Since there are only two screws on each side, a straight rod is placed to link the two and set screws are placed and tightened. Keep the rods as short as possible.

3 Posterior fusion top

Indications

Fusion is typically indicated in:

  • elderly patients when implant removal is not planned
  • complex injuries requiring a long time to heal

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Fusion following C1-C2 stabilization

Fashion the bone graft as illustrated.


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Place a wire under the left rod over the graft and under the right rod and cinch it in place to push the graft onto the decorticated C1 posterior arch and C2 lamina.


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Add additional cancellous autograft strips to fill the voids between the lamina of C2 and the structural autograft.


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Alternatively (or additionally) the facet joints of C1-C2 can be opened, decorticated and fused.


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Cancellous allograft placed dorsally over the lamina does not work in the vast majority of cases and should be avoided. One can place cancellous allograft intra-articulary after decorticating.

To decorticate the joint, reflect the C2 nerve cranially.


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Burr into the joint or use a curette to scrape the articular cartilage. Be aware that the vertebral artery can in some cases be just below the articular surface of C2. This can be verified by CT scan.


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Fusion following C2-C3 stabilization

The lamina and facets are decorticated and bone graft placed.

v1.0 2016.12.01