Possible risks and complications with placement of thoracic instrumentation include:

• Non-union
• Adjacent Disc Disease: Recurrent pain after successful spinal fusion and instrumentation procedure is more likely due to a "transfer" lesion at the motion segment above or below the fusion, because stress is transferred to the next level and may cause that vertebral segment to degenerate and breakdown.
• Nerve Damage: Nerve damage can occur with placement of the instrumentation, or if the instrumentation dislodges or migrates.
• Bleeding
• Infection

Risks with the procedure are very particular to the surgical approach that is used (anterior versus posterior).

Posterior (pedicle)
Posterior thoracic pedicle screws are difficult to place due to the smaller size of the pedicles in the thoracic spine as compared to the lumbar spine. Additionally, with deformities such as scoliosis, the shape, size, and orientation of the pedicle can vary significantly. Specific complications with thoracic pedicle screws include spinal cord or nerve injury, injury to the lungs or pneumothorax, and injury to the great vessels.

Posterior (lamina or spinous process)
Neurologic injury can occur with passage of wires or hooks under the lamina, or dislodgement of the instrumentation.

Anterior
Anterior instrumentation has the risk of an injury to the largest blood vessels (aorta, vena cava), or injury to the spinal cord or nerves that pass adjacent to the disc. The cages or screws can also potentially extrude into the thoracic cavity and may need to be retrieved to prevent them from eroding into a major blood vessel.