atlantookzipitale Subluxation

Neuroimaging assessment in Down syndrome: a pictorial review. a Sagittal T2/TSE of a 12-year-old Down syndrome patient showing a small and flattened shape of the occipital condyle as well as the C1 superior articular facet, with some degree of anterior luxation of C1. b Sagittal T2/TSE of a normal 12-year-old boy for comparison; there is normal curved shape of articular facets

Neuroimaging

assessment in Down syndrome: a pictorial review. a Sagittal T2/TSE of a 12-year-old Down syndrome patient showing a small and flattened shape of the occipital condyle as well as the C1 superior articular facet, with some degree of anterior luxation of C1. b Sagittal T2/TSE of a normal 12-year-old boy for comparison; there is normal curved shape of articular facets

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School ager with Trisomy 21. Lateral radiograph of the cervical spine in flexion (left) shows a normal atlanto dens interval and normal relationship of the occipital condyles to the lateral masses of C1 while on extension (right) there is posterior translation of the occipital condyles in relation to the lateral masses of C1.The diagnosis was atlanto occipital instability in a patient with Trisomy 21.

School ager

with Trisomy 21. Lateral radiograph of the cervical spine in flexion (left) shows a normal atlanto dens interval and normal relationship of the occipital condyles to the lateral masses of C1 while on extension (right) there is posterior translation of the occipital condyles in relation to the lateral masses of C1.The diagnosis was atlanto occipital instability in a patient with Trisomy 21.

pediatricimaging.org • CC-by-nc-sa 4.0

Atlanto-occipital dissociation injuries • Traynelis classification of atlanto-occipital dissociation (diagrams) - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Traynelis classification of atlanto-occipital dissociation (diagrams) - Ganzer Fall bei Radiopaedia

Hacking C, Traynelis classification of atlanto-occipital dissociation (diagrams). Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-87200 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlantooccipital dissociation - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlantooccipital dissociation - Ganzer Fall bei Radiopaedia

Gaillard F, Atlantooccipital dissociation. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-10273 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Base of skull lines (annotated images) - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Base of skull lines (annotated images) - Ganzer Fall bei Radiopaedia

Hacking C, Base of skull lines (annotated images). Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-40491 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital disassociation - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital disassociation - Ganzer Fall bei Radiopaedia

Gaillard F, Atlanto-occipital disassociation. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-8015 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital dissociation injury - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital dissociation injury - Ganzer Fall bei Radiopaedia

Skalski M, Atlanto-occipital dissociation injury. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-29274 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital dislocation - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital dislocation - Ganzer Fall bei Radiopaedia

Wong C, Atlanto-occipital dislocation. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-44648 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital and atlantoaxial distraction - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital and atlantoaxial distraction - Ganzer Fall bei Radiopaedia

Gaillard F, Atlanto-occipital and atlantoaxial distraction. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-48613 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Craniocervical dissociation with basilar artery transection - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Craniocervical dissociation with basilar artery transection - Ganzer Fall bei Radiopaedia

Altadill A, Craniocervical dissociation with basilar artery transection. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-81046 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Craniocervical dissociation - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Craniocervical dissociation - Ganzer Fall bei Radiopaedia

Glick Y, Craniocervical dissociation. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-52910 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital dissociation - Traynelis type 1 - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital dissociation - Traynelis type 1 - Ganzer Fall bei Radiopaedia

Hacking C, Atlanto-occipital dissociation - Traynelis type 1. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-87570 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital dissociation (Traynelis type 1), C2 teardrop fracture, C6/7 facet joint dislocation - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital dissociation (Traynelis type 1), C2 teardrop fracture, C6/7 facet joint dislocation - Ganzer Fall bei Radiopaedia

Hacking C, Atlanto-occipital dissociation (Traynelis type 1), C2 teardrop fracture, C6/7 facet joint dislocation. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-87655 • CC by-nc-sa 3.0 (modified)

Atlanto-occipital dissociation injuries • Atlanto-occipital dissociation with vertebral artery transection - Ganzer Fall bei Radiopaedia

Atlanto-occipital

dissociation injuries • Atlanto-occipital dissociation with vertebral artery transection - Ganzer Fall bei Radiopaedia

Newman C, Atlanto-occipital dissociation with vertebral artery transection. Case study, Radiopaedia.org (Accessed on 05 Jan 2023) https://doi.org/10.53347/rID-98641 • CC by-nc-sa 3.0 (modified)

Teenager hit by a car. Coronal CT without contrast of the cervical spine (above left) shows a fracture through the left occipital condyle with the fracture fragment displaced inferiorly. Additionally, the occipital condyles do not articulate with the lateral masses of the C1 vertebral body. Left sagittal CT (above middle) again shows the left occipital condyle fracture and increased space between the left occipital condyle and the left lateral mass of C1. Right sagittal CT (above right) shows even more clearly the increased space between the right occipital condyle and the right lateral mass of C1. Midline sagittal CT (below) shows the basion-dens interval to be abnormally increased.The diagnosis was atlanto-occipital dissociation.

Teenager hit

by a car. Coronal CT without contrast of the cervical spine (above left) shows a fracture through the left occipital condyle with the fracture fragment displaced inferiorly. Additionally, the occipital condyles do not articulate with the lateral masses of the C1 vertebral body. Left sagittal CT (above middle) again shows the left occipital condyle fracture and increased space between the left occipital condyle and the left lateral mass of C1. Right sagittal CT (above right) shows even more clearly the increased space between the right occipital condyle and the right lateral mass of C1. Midline sagittal CT (below) shows the basion-dens interval to be abnormally increased.The diagnosis was atlanto-occipital dissociation.

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Radiopaedia • CC-by-nc-sa 3.0 • de

siehe auch

Atlantodentalarthrose
Down-Syndrom
atlantodentaler Abstand
okzipitozervikale Instabilität
Power-Quotient

Atlanto-occipital dissociation injuries are severe and include both atlanto-occipital dislocations and atlanto-occipital subluxations.

Pathology

The tectorial membrane and alar ligaments provide most of the stability to the atlanto-occipital joint, and injury to these ligaments results in instability due to low inherent osseous stability .

Radiographic features

The key to the diagnosis, in addition to visualizing gross disruption of the normal alignment of the atlanto-occipital joint, hinges on using a number of lines on the lateral horizontal shoot-through cervical spine film :

basion-dens interval (BDI) >10 mm in adults
basion-axial interval (BAI) >12 mm in adults
Powers ratio >1 (insensitive to a vertical distraction injury or posterior dissociation)
atlantodental interval (ADI)
- >3 mm in adult males
- >2.5 mm in adult females

CT

For pediatric patients the condyle-C1 interval (CCI) has been shown to provide the highest diagnostic accuracy.

condyle-C1 interval (CCI) > 4 mm in children

Differential diagnosis

occipital condyle fracture
Jefferson fracture: anterior and posterior C1 ring fracture, possible lateral masses displacement
odontoid fracture: type 2 will cause posterior dens displacement and will disrupt Powers ratio
atlanto-axial subluxation: atlantoaxial rotatory fixation will cause C1 lateral mass asymmetry relative to the dens
Down syndrome: atlanto-occipital instability due to laxity of alar ligament
rheumatoid arthritis: CT/MRI will show atlantooccipital instability due to pannus destabilisation of joints and ligaments, and x-ray will show erosions