Executive Editor: Luiz Vialle General Editor: German Ochoa (in memoriam)

Authors: Alex Vaccaro, Frank Kandziora, Michael Fehlings, Rajasekaran Shanmughanathan

Thoracic and lumbar trauma - A4

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Glossary

1 Introduction top

Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Preliminary remarks

A4 injuries are axial compression injuries and involve a fracture of the posterior wall of the vertebral body and both the superior and inferior end plates. Due to axial compression forces, vertical fracture of the lamina is usually present and does not indicate a tension band failure.


Decompression

In cases where neurological deficit is observed and compression of the spinal canal is assumed, decompression has to be performed. It should be understood that this is a step that can also result in deterioration of neurology unless very meticulously performed.
Decompression can be performed anteriorly or posteriorly. Posteriorly, decompression can be indirect or direct. Indirect decompression may be tried before performing direct decompression. Please refer to Decompression techniques for a detailed discussion of indications for the posterior decompression techniques. ( Posterior decompression)

2 Closed reduction top

Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Primary reduction is performed by positioning of the patient onto a frame to create lordosis.

3 Reduction with pedicle screws top

Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Preliminary remarks

Due to the fact that bilateral instrumentation is necessary in all cases, all steps described below are repeated on the opposite side, unless stated otherwise.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Pedicle screw insertion

In patients with A4 injury at the thoracic level, posterior long segment fixation is performed to provide better reduction forces. Fixation of multiple spinal segments does not affect functionality in the thoracic spine due to the presence of rigid rib cage.

In this technique, pedicle screws are inserted two levels above and below the fractured level on both sides.

This is essential in rotationally unstable injuries where stress on the posterior implants is high. ( Pedicle screw insertion)


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Rod contouring

The contouring of the rod depends on the site of the fracture.  A rod contoured in mild kyphosis is chosen for fractures from T1-T10. A straight or a slightly lordotic rod is chosen for fractures from T11-L1, and a rod contoured to lordosis is chosen for lumbar fractures.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Rod insertion

The rod is inserted sequentially, either from distal to proximal or the other way round. The distal screw heads are tightened.

The rod is then inserted into the proximal screw heads without tightening.

Proper rod contouring helps in achieving appropriate sagittal alignment.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Decompression

If it is decided to perform an indirect decompression, this is done at this stage. If indirect decompression proves to be insufficient, a direct decompreesion eg, posterior or transpedicular decompression are undertaken.  Refer to the Posterior Decompression techniques for detailed instructions. ( Posterior decompression)


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Distraction (ligamentotaxis)

With the help of a distractor, the proximal screws are distracted along the rod. This is done on both sides simultaneously.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

The screw heads are tightened with the inner nuts to secure the reduction achieved.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Cross links are applied at the top and bottom of the construct to provide biomechanical stability. In type A injuries one cross link might be sufficient.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

The final construct is shown from a lateral view

4 Fusion top

Decision

Although fusion was routinely performed for all spinal fractures, its indications are now being restricted to fractures that are highly unstable.

Nonfusion fixations can be performed for A3, A4, and B1 type injuries.
Fusion is routinely performed for A2, B2, B3, and all C injuries as they are unstable injuries with extensive soft tissue and ligamentous disruption.


Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Nonfusion

For nonfusion surgeries, the facet joint capsule is preserved during the entire procedure.

The screws can be removed after 9 months once the fracture has healed.

5 Intraoperative imaging top

Thoracic and lumbar fractures: Posterior long segment fixation enlarge

Prior to wound closure, intraoperative imaging is performed to check the adequacy of reduction, position, and length of screws and the overall coronal and sagittal spinal alignment.

v1.0 2014-12-99