Executive Editor: Luiz Vialle

Authors: Carlo Bellabarba, Marcelo Gruenberg, Cumhur Oner

Subaxial cervical trauma - B3 Cervical spine - posterior fixation

back to Spine overview


1 Introduction top

Posterior instrumentation is either combined with open reduction, or is performed after closed reduction has been successfully achieved

MRI should be obtained preoperatively to rule out the presence of a significant disk herniation before attempting open reduction through a posterior approach.

In certain situations involving the presence of severe neurological compromise after a failed attempt at closed reduction, an open reduction can be performed even without MRI if early reduction is a priority.

Direct decompression of spinal canal caused by a vertebral body fracture intruding into the canal anteriorly cannot be addressed with a posterior approach.


Lateral mass screws vs. pedicle screws

Fixation can be achieved with either lateral mass screws, pedicle screws or combination of the two.

Because lateral mass fixation is generally sufficient, and carries less risk, pedicle screw fixation is limited to rare cases where lateral mass fixation would be insufficient or not possible.

Surgical complications

More details on surgical complications can be found here.

2 Positioning and approach top


Posterior fixation is achieved with the patient in the prone position, through the posterior approach to the cervical spine.

3 Decompression top


A spinal cord anterior compression cannot be addressed by a posterior approach.

On the other hand, nerve root decompression can be achieved directly through the posterior approach by removal of a displaced facet or fragment from the foramen.

4 Reduction top


Depending on surgeons preference, reduction can be performed either open or closed.

Closed reduction can be performed preoperatively with:

  • halo traction
  • halo with manipulation under anaesthesia

Open reduction can be performed on admission or in case of failed closed reduction.

When realigning B fractures under traction, care should be taken to prevent over-distraction.

Note: A halo device does not only serve for reduction, but is also an immobilization method.

5 Instrumentation top


Unless associated with an ankylosing spine condition, B3 injuries are mostly treated utilizing an anterior approach.

When an anterior approach is combined with a posterior fixation (eg. due to an ankylotic spine), posterior instrumentation will include one level above and one level below the disruption.

6 Rod insertion top


The cervical spine lordosis must be obtained with patient positioning/reduction. The rod should be bent to keep this lordosis.

Incorrect lordosis is one of the main pitfalls of this procedure.


The screws are closed with slight compression to enhance the stability of the construct. This procedure is typically followed by anterior fixaiton. If posterior fixation alone is considered 2-3 levels above and below should instrumented.