AO Spine classification of sacral injuries
The AO Spine classification of sacral injuries aims to simplify and universalise the process of classifying sacral injuries and improve interobserver and intraobserver reliability.
The AO Spine sacral classification is broken into three subsections that follow a hierarchical structure similar to the AO classifications of the thoracolumbar spine.
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Injury types (A, B or C)
Injuries are broadly categorized into three groups based on the region of injury:
- A: lower sacrococcygeal injuries
- B: posterior pelvic injuries
- C: spinopelvic injuries
A: lower sacrococcygeal injuries
Type A injuries involve the lower portion of the sacrococcygeal region. The stability of both the pelvis and the spinopelvic region are unaffected by type A injuries, however higher A-type injuries can have associated neurological impact.
- A1: injury to the coccygeal region or compression injuries including that of ligamentous avulsion fractures
- A2: fractures below the level of the sacroiliac joint that are non-displaced and transverse in orientation
- A3: fractures below the level of the sacroiliac joint that are displaced and transverse in orientation
B: posterior pelvic injuries
Type B injuries are categorized as fractures of the sacrum which are unilateral and longitudinal in orientation whereby the ipsilateral superior S1 facet is no longer discontinuous with the medial aspect of the sacrum. Unlike type A, type B injuries have an impact on the stability of the pelvis, however a minimal impact on the spinopelvic region.
- B1: a fracture that is longitudinal in orientation, medial to the foramen and involves the spinal canal
- B2: a fracture that is longitudinal in orientation, lateral to the foramen and does not involve the spinal canal nor the foramen
- B3: a fracture that is longitudinal in orientation involving the foramen but not the spinal canal
C: spinopelvic injuries
Type C injuries always result in instability of the spinopelvic region
- C0: nondisplaced sacral U-type variant fracture
- C1: a sacral U-type variant without any posterior pelvic instability
- C2: bilateral complete B-type fracture without transverse component
- C3: displaced sacral U-type variant fracture
Neurological signs (N)
- Nx: the patient cannot be examined
- N0: no neurological deficits
- N1: transient neurological injury
- N2: nerve root injury
- N3: cauda equina syndrome/incomplete spinal cord injury
- N4: complete spinal cord injury
Modifiers (M)
- M1: soft tissue injury
- M2: metabolic bone disease
- M3: anterior pelvic ring injury
- M4: sacroiliac joint injury
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fracture
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- avulsion fracture
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spinal fractures
- classification (AO Spine classification systems)
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cervical spine fracture classification systems
- AO classification of upper cervical injuries
- AO classification of subaxial injuries
- Anderson and D'Alonzo classification (odontoid fracture)
- Roy-Camille classification (odontoid process fracture)
- Levine and Edwards classification (hangman fracture)
- Allen and Ferguson classification (subaxial spine injuries)
- subaxial cervical spine injury classification (SLIC)
- thoracolumbar spinal fracture classification systems
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- classification of sacral fractures
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cervical spine fracture classification systems
- spinal fractures by region
- spinal fracture types
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- rib fractures
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upper limb fractures
- classification
- Rockwood classification (acromioclavicular joint injury)
- AO classification (clavicle fracture)
- Neer classification (clavicle fracture)
- Neer classification (proximal humeral fracture)
- AO classification (proximal humeral fracture)
- AO/OTA classification of distal humeral fractures
- Milch classification (lateral humeral condyle fracture)
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- Bado classification of Monteggia fracture-dislocations (radius-ulna)
- Mason classification (radial head fracture)
- Frykman classification (distal radial fracture)
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- upper limb fractures by region
- shoulder
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scapular fracture
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- hip
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- pelvic fracture
- sacral fracture
- coccygeal fracture
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hip
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- femoral head fracture
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femoral neck fracture
- subcapital fracture
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trochanteric fracture
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- ankle
- foot
- tarsal bones
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Spinal trauma
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spinal fractures
- morphology
- chalk-stick fracture
- compression fracture
- fractures by location
- classifications
- AO spine classification systems
-
cervical spine fracture classification systems
- AO classification of upper cervical injuries
- AO classification of subaxial injuries
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- Levine and Edwards classification (hangman fracture)
- Roy-Camille classification (odontoid process fracture )
- Allen and Ferguson classification (subaxial spine injuries)
- thoracolumbar spinal fracture classification systems
- three column concept of spinal fractures (Denis classification)
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- morphology
- facet dislocation
- listhesis