Authors of section

Authors

Ronald Lehman, Daniel Riew, Klaus Schnake

General Editor

Luiz Vialle

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Posterior fixation

1. Introduction

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
posterior fixation

Local anatomy

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

posterior c1 c2 fixation

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.

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.

posterior c1 c2 fixation

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.
posterior c1 c2 fixation

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.

posterior c1 c2 fixation

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
posterior fixation

2. Appraoch and positioning

This procedure is performed through a posterior approach with the patient placed in the prone position.

posterior fixation

3. Posterior internal fixation

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.

occipitocervical fusion screw fixation

C2 screw placement

C2 can be fixed using either of the three techniques:

occipitocervical fusion screw fixation

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.

posterior c1 c2 fixation

C3 screw placement

C3 can be fixed using lateral mass screws.

lateral mass screw insertion magerl technique

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.

posterior c1 c2 fixation

4. Posterior fusion

Indications

Fusion is typically indicated in:

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

Fusion following C1-C2 stabilization

Fashion the bone graft as illustrated.

posterior c1 c2 fixation

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.

posterior c1 c2 fixation

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

posterior c1 c2 fixation

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

posterior c1 c2 fixation

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.

posterior c1 c2 fixation

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.

anderson dalonzo type iii

Fusion following C2-C3 stabilization

The lamina and facets are decorticated and bone graft placed.

c2 body fracture

5. Aftercare

Patients are made to sit up in the bed on the evening following the operation.

A collar is commonly used following surgical stabilization to moderate patient activity.

The purpose of a collar is to prevent ranges of motion outside of limits deemed unfavorable for fracture healing. Collar is optional.

Patients with intact neurological status are made to stand and walk on the first day after surgery. Patients can be discharged when medically stable or sent to a rehabilitation center if further care is necessary. This depends on the comfort levels and presence of other associated injuries.

Patients are generally followed with periodical x-rays at 6 weeks, 3 months, 6 months, and 1 year.