Traynelis classification of atlanto-occipital dislocations

Last revised by Francis Deng on 17 Jan 2022

The Traynelis classification of atlanto-occipital dislocations describes injuries of the atlanto-occipital joint according to the displacement of the occipital condyles relative to the atlas:

  • type I: anterior displacement
  • type II: longitudinal distraction (superior-inferior displacement)
  • type III: posterior displacement

A limitation of this classification system is that rotatory or coronal malalignment are not taken into consideration.

Treatment and prognosis

Type I and III injuries are treated with longitudinal traction to reduce the dislocation followed by surgical fixation. Non-operative management including collar or halo immobilization is used for certain patients but has a high rate of failure. Persistent traction is contraindicated due to the increased rate of neurological complications.

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Cases and figures

  • Figure 1: normal alignment
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  • Figure 2a: type 1
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  • Case 1: type 1
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  • Figure 2b: type 2
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  • Case 2: type 2
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  • Figure 2c: type 3
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