Pathology
Paediatric populations predisposed
- due to lateral mass anatomy and ligamentous laxity
- both alar ligaments and facet capsules must be torn to occur
Aetiology
Due to forced rotation and lateral tilt
Can be spontaneous
Presentation
Most patients have torticollis and limited rotation
Cock robin position
- lateral flexion and rotation to other side
Fielding Classification
1. Rotatory fixation without anterior displacement
2. Rotatory fixation with anterior displacement 3 - 5 mm
3. Rotatory fixation with anterior displacement > 5mm
- indicates disruption of both facet joints and transverse ligament
4. Rotatory fixation with posterior displacement
Associations
Downs
RA
Klippel Feil
Morquio
SED
Achondroplasia
DDx
Torticollis
Atlantoaxial rotatory fixation
Ondontoid fracture
Os Ondontoid
Grisel's syndrome
Pyogenic atlanto-axial subluxation
- after upper respiratory tract infection
- inflammation induced ligamentous laxity
- can be post tonsillectomy
Present with painful torticollis and limited rotation
Xray
Widened atlanto - lateral mass interval
Dynamic CT
Head turned to left then to right
- demonstrate fixed subluxation
Management
Atlanto-axial instability
1. Early presentation
- i.e. first day or two
- trial soft collar / analgesics
- see 1 week later
2. Reduce any anterior displacement with halter traction
- add sequential weight
- check X-ray to ensure no C0/1 displacement
- valium and Phenergan
- if successful apply HTB
- flexion extension views out of HTB for residual instability
3. Failure halter traction / Trial skeletal traction
4. Failure skeletal traction / Open reduction and fusion
Residual instability
C1/2 Gallie fusion
Chronic
> 3/12
- consider fusion in situ
Grisel's
Usually will reduce spontaneously
First week
- NSAIDS and hard collar
Failure or > 1 week symptoms
- soft halter traction
> 4 weeks
- skeletal traction and HTB once reduced