- See:
-
C1 /
C2
-
AtlantoAxial Rotatory Subluxation in Down's Syndrome:
-
Atlantooccipital Disassociation:
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Atlantoaxial Rotatory Fixation:
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Atlantoaxial Subluxation in R.A.:
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Cross Table Lateral:
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Occipital-Atlanto-Axial Anomalies:
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Posterior Atlanto-Axial Arthrodesis
-
Torticollis:
- Discussion:
- refers to loss of ligamentous stability between atlas and axis;
- occurs most often in older children and adolescents;
- mechanism of injury in atlantoaxial rotatory subluxation is unknown, but is usually due to forced rotation of the neck along w/ some element of lateral tilt;
- it can occur spontaneously or after trauma;
- complete C1-C2 dislocation is a known complication of football spearing;
- pts complain of neck pain, occipital neuralgia, and occassionally symptoms of vertebrobasilar artery insufficiency;
-
prognosis:
- significant potential for continued displacement of atlas on axis w/ resultant pressure on spinal cord;
- vertebrobasilar artery insufficiency may lead to cerebral infarcts;
- Atlanto-Axial Articulation:
- approx 50 % of cervical rotation takes place between atlas and axis, around laterally central but anteriorly eccentric odontoid process;
- lateral wall of atlas rotates to across canal of axis, physiologically decreasing opening between these 2 segments;
- spinal canal of the atlas is large compared w/ that of other segments, which rotation around axis along w/ translational
displacement without pressure on the spinal cord;
-
Steele's Rule of Thirds:
- canal of atlas is about 3 cm in its AP diameter;
- spinal cord, odontoid process, and free space for cord are each about 1 cm in diameter;
- anterior displacement of the atlas that exceeds one centimeter may jeopardize the adjacent segment of the spinal cord;
- Associated Conditions:
-
Down syndrome (25% of patients);
-
Rheumatiod Arthritis (adults);
-
Grisel's syndrome:
- atlantoaxial instability may be noted in nl child in association w/ pharyngeal infection (
Grisel's syndrome);
- hyperemia causes demineralization of attachment of transverse ligament to anterior arch of
atlas, with subsequent rotary
subluxation of atlas on
axis or anterior atlantoaxial subluxation;
-
Klippel Feil;
-
Morquio syndrome;
-
Spondyloepiphyseal dysplasia:
-
Achondroplasia:
- Larsen's syndrome:
- Diff Dx:
-
Torticollis;
-
Atlantoaxial Rotatory Fixation:
-
Odontoid Fractures
- Congenital Anomalies:
-
os odontoideum:
- congenital absence of the odontoid process;
- Radiographs:
-
Lateral View:
-
ADI < 3.5 mm in flexion, implies that the
transverse ligament is intact;
-
ADI 3-5 mm, transverse ligament is insufficient; (this is a type II injury);
- in children upto 4.5 mm may be normal;
-
ADI > 5 mm:
- indicates failure of the alar ligaments;
- consistent w/ type III
rotatory subluxation;
- Non Operative Treatment:
-
Grissel's syndrome
- vast majority of pts w/ this form of
torticollis improve spontaneously;
- w/ the subluxation does not resolve, the child should be admited for Halter traction (in order to avoid
rotatory fixation);
- in those few cases in which persistent instability is present, stabilization by
posterior atlantoaxial arthrodesis is required;
-
Children:
- children w/ radiographic evidence of
transverse ligament disruption can be treated non operatively in acute
cases (less than 3 wks) in which there is no indication of transient or permanent neurological deficit;
- requires treatment in halter or skull traction (NSAIDS and muscle relaxants may be given as necessary);
- following reduction, pt is kept in traction or a
halo 3 months;
- recurrence of deformity is possible, even with this treatment, and therefore
flexion-extension radiographs are needed after halo has been removed;
-
Adults: should not be treated non operatively, since ligament healing potential is unreliable;
-
Elderly Patient: in some cases, can be managed non-operatively, because few demands are made on neck;
- Arthrodesis:
- indications for fusion:
-
children:
- fusion is indicated w/ neurologic involvement;
- persistent anterior displacement;
- deformity present for more than 3 months;
- recurrence of deformity following 6 wks of immobilization;
-
young adults:
- instability, w/ or w/o pain, is treated w/ arthrodesis, because trivial trauma might lead to catastrophic cord injury;
- w/ moderate displacement that minimally shifts on flexion & extension views may undergo further gradual displacement of atlas
over time which again places the cord at risk;
- considerations for fusion:
- fusion should be proceded by 2 to 3 weeks of skeletal traction
- after skeletal traction is continued for 6 wks or use a
halo cast
- extension reduction and surgical stabilization followed by 8-12 weeks in
halo jacket;
- w/ chronic subluxation, operative reduction should not be attempt, and rather the surgeon should accept a fusion
in situ or should perform occiput to C2 fusion;
- posterior C1-C2 arthrodesis:
Atlanto-axial instability and spinal cord compression in children--diagnosis by computerized tomography.
Atlanto-axial fusion for instability.
Spine fusion for atlanto-axial instability.
