Atlanto Occipital Dislocation

 

Occipito atlanto dislocationOccipitocondyle dis 2

 

Epidemiology

 

High energy trauma

Usually deadly

 

Zivot et al Am J Forensic Med Pathol 1993

- autopsies of 85 fatal pedestrian - MVA accidents

- 31% had atlanto occipital dislocation

- death likely due to brainstem injury

 

Children

 

More common in children due to

- larger head to body ratio

- relative ligamentous laxity

- horizontal atlanto-occipital joints

 

Types

 

Pure ligament injury usually

 

Atlanto occipital dislocation anteriorAtlanto occipital dislocation verticalAtlanto occipital dislocation posterior

 

Direction

- anterior occipital displacement (most common / head anterior)

- vertical

- posterior (rare)

 

Xray / CT measurements

 

Frequently missed on xray

 

Powers ratioBAI BDI

 

Basion-Dens Interval / BDI

- basion to tip of dens

- vertical displacement > 12 mm

 

Basion-Axial Interval / BAI

- basion to posterior border ondontoid

- anterior displacement > 4 mm

 

Power Ratio BC/AO > 1 

- basion to posterior arch / opisthion to anterior arch

 

Atlanto occipital dislocation

From: Kim et al Korean Journal of Spine 2012

 

Atlanto occipital dislocation

From: Kim et al Korean Journal of Spine 2012

 

Management

 

Outcomes

 

Joaquim et al Int J Spine Surg 2021

- systematic review of 17 articles and 341 patients who survived to hospital

- mortality rate 35%

- mean GCS 8

- high incidence of cardiac arrest

- high association of intra-cranial injury

- 11% severe neurological injury

- majority survivors treated with occipito-cervical fusion

 

Reduction and Halo-Thoracic Brace (HTB)

 

Reduce in OT

- image intensifier

- putting sandbags under thorax

- allows head to reduce posteriorly

- assess with image intensifier

- apply halo vest

- add compression

 

HTB 3 months

- assess stabilty with flexion / extension views

 

Surgical stabilization

 

Occipito-cervical fusion