Anterior odontoid screw fixation

 

Procedure

Direct fixation of the odontoid peg (see ‘The normal structure of the spine’) through the front of the neck. One or two screws are placed from the bottom of the C2 vertebra through the entire length of the peg fixing the fracture. It is preferable to use two screws to avoid instability in rotation. The approach is done through an incision in the middle of the neck on the right side.

Indication  

Fracture of the odontoid peg. This technique is only suitable for some types of fractures (posterior subluxation) and should not be performed if the fracture line is oblique upwards which causes an anterior subluxation.

Risks    

Bleeding, Infection, neurological deficit including paralysis, death (extremely rare), injury to vessels, hoarse voice, non-union (if the fracture does not heal), malpositioning of the screws, slippage/subluxation of the fracture despite fixation.

Hospital stay

24-48 hours after operation in majority of cases but depends on the underlying problem.

Anaesthesia

Always general anaesthesia

Outcome     

The vast majority of patients will have good healing of the fracture. The neck movement will be normal or near to normal in the long term.

Recovery

The neck will feel sore for a short while but unless there are complications, recovery is quick. Some patients will need a hard collar for 4-12 months depending on the fracture. Patients can mobilise immediately after surgery if good fixation is achieved.

Commonly asked questions

Does it matter if one or two screws are used?
The technique was originally described for two screws. The first screw pulls the fractured fragment back against the body of the vertebra and the second prevents rotation. However, the odontoid peg is a small piece of bone and it can be difficult to place two screws into it. One good screw is better than two suboptimal screws. If only one screw is placed, patients should ware a hard collar until the bone shows signs of healing. There is no evidence that placing only one screw has a worse outcome than two screws.

What other techniques can be used if an anterior odontoid screw is not indicated?
This depends largely on the type of underlying fracture. The most common type of fixation is a posterior (from the back of the neck) fixation called C1/2 fusion

Type 2 fracture of C" before and after surgery

Type 2 fracture of C2 before and after surgery

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