1. Daniel S. Chow, MD Jason Talbott, MD
Mechanism Based Approaches to Identifications of Traumatic Spine Injury
Daniel S. Chow, MD
Jason Talbott, MD

2. Disclosures
The authors have no conflicting financial disclosures.

3. Content Organization Background Overview of Classifications
Examples by Mechanism
Post Quiz

4. Background Epidemiology of spine trauma within the US:
Incidence: ,500
Prevalence: 240,000 to 337,000
Mean age: years
Impact on patients & society:
Incomplete tetra- and paraplegia make up 66% of outcomes
Lifetime cost is variable, but mean yearly expense is estimated at $71,961 per patient
National Spinal Cord Injury Statistical Center, Facts and Figures at a Glance. Birmingham, AL: University of Alabama at Birmingham, 2015.

5. Overview of Spine Trauma Classification
Watson & Jones
(1938)
Holdsworth
(1963) AO
(1994)
1920
1940
1960
1980
2000
Böhler
(1932)
Nicoll
(1949)
Denis & McAfee
(1983)
TLICS
(2005)
Böhler
1962 – Holdsworth
1983 – Denis & mcafee
1994- AO
2005 TLICS
Classification allow for uniform description of injury.
Over time, classification of spine injury can broadly be divided into
anatomic changes and mechanism of injury.

6. Title page from Watson & Jones 1938 article
Overview of Spine Trauma Classification Böhler, Watson/Jones, and Nicoll
1930 – 1949
Böhler (1930) described five categories of injury based on mechanism of injury. However, this classification did attempt to identify instability.
Compression
Shear
Flexion – Distraction
Rotational
Extension
Watson & Jones (1938) evaluated a series of 252 radiographs. Built on Böhler’s study and added:
Concept of instability and influence on treatment
Importance of the posterior longitudinal ligament for stability
Böhler2 initially attempted to classify thoracolumbar spine fractures using five injury types. He combined both anatomic appearance and mechanisms of injury to include compression fractures, flexion-distraction injuries, extension fractures, shear fractures, and rotational injuries in his classification scheme. Böhler, however, did not attempt to define instability patterns based on the anatomical appearance of the injury.
Nicoll (1949) evaluated a series of 152 radiographs. Built on prior studies and described an anatomic based classification, stressing the importance of the vertebral body, disc, intervertebral joint, and interspinous ligament.
Title page from Watson & Jones 1938 article

7. Overview of Spine Trauma Classification Holdsworth
1962
Holdsworth (1962) introduces new classification scheme based on two column model in a review of over 1000 patients who suffered traumatic paraplegia.
Stressed the importance of the posterior longitudinal ligament.
Böhler2 initially attempted to classify thoracolumbar spine fractures using five injury types. He combined both anatomic appearance and mechanisms of injury to include compression fractures, flexion-distraction injuries, extension fractures, shear fractures, and rotational injuries in his classification scheme. Böhler, however, did not attempt to define instability patterns based on the anatomical appearance of the injury.
Anterior
Ant. longitudinal ligament
Vertebral body
Intervertebral disc
Post. longitudinal ligament
Posterior
Posterior joint
Interspinous ligament
Supraspinous ligament
Anterior Posterior

8. Overview of Spine Trauma Classification Denis & McAfee
1983
In 1983, Francis Denis introduces a 3-column approach
Based on retrospective review of 412 fractures.
Combination of both mechanism of injury and anatomy.
Compression (4 types)
Burst (5 types)
Seat Belt (4 types)
Fracture – Dislocation (3 types)
In 1983, McAfee also describes a 3-column model in 100 patients and also stresses the importance of the middle column.
Anterior Posterior
Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976) Nov-Dec;8(8):
Baker AD. Classic Papers in Orthopaedics (2013). The Three Column Spine and Its Significance in the Classification of Acute Thoracolumbar Spinal Injuries. pp
Anterior Middle Posterior

9. Overview of Spine Trauma Classification Denis & McAfee
1983
Pros
Easy to understand conceptually
Most frequently cited (and probably still most frequently used)
Cons
Does not account for patient clinical status
Does not take into account of ligamentous support, which limits accurate assessment of stability.
Con: stable vs unstable can be confusion?
Anterior
Ant. Longitudinal Ligament
Ant. Annulus
Ant. 2/3 Vertebral body
Middle
Post. Longitudinal Ligament
Post. Annulus
Post. 2/3 Vertebral body
Posterior
Posterior bony elements (pedicles, lamina, spinous process)
Posterior ligaments
Anterior Middle Posterior

10. Overview of Spine Trauma Classification Magerl Classification
1994
Magerl (1994) introduces new classification scheme based on mechanism on injury and two column model in a review of over 1400 patients.
Three types BUT over 50 subtypes (see following slide).
Compression
Flexion-Extension
Rotational
Review of 1445 cases
3 types with over 50 patterns
Very detailed ; however, very complex and not practically reproducible
Very poor reproducibility interobserver
Pros
Very detailed
Considers both fracture pattern and mechanism
Cons
Overly complex
Poor reproducibility
Does not account for clinical status

11. Overview of Spine Trauma Classification Magerl – AO Classification
1994
Type A. Vertebral body compression
A1 (Impaction fractures)
A1.1 Endplate impaction
A1.2 Wedge impact (3)
A1.3 Vertebral body collapse
A2 (Split fractures)
A2.1 Sagittal split
A2.2 Coronal split
A2.3 Pincer
A3 (Burst fractures)
A3.1 Incomplete (3)
A3.2 Burst-split (3)
A3.3 Complete (3)
Type B. Ant & Post Element Injury
B1 Posterior disruption predominantly ligamentous (Flexion-distraction)
B1.1 with disruption of disc (3)
B1.2 with type A fracture (3)
B2 Posterior disruption predominantly osseus (Flexion-distraction)
B2.1 Transverse bicolumn
B2.2 With disruption of disc (2)
B2.3 With type A fracture (2)
B3 Ant disc disruption (Hyperextension)
B3.1 with subluxation (2)
B3.2 with spondylolysis
B3.3 with posterior dislocation
Type C. Ant & Post Element with rotation
C1 Type A with rotation
C1.1 Rotational wedge
C1.2 Rotation split (4)
C1.3 Rotational burst (3)
C2 Type B with rotation
C2.1 B1 with rotation (7)
C2.2 B2 with rotation (3)
C2.3 B3 with rotation (3)
C3 Rotational - Shear
C3.1 Slice fracture
C3.2 Oblique fracutre
* () indicate number of subtpes
Magerl F. A comprehensive classification of thoracic and lumbar injuries. Eur Spine J. 1994;3(4):

12. Overview of Spine Trauma Classification TLICS
2005
Spine Trauma Study Group (2005) introduces Thoracolumbar Injury Classification Score, which assigns points based on:
Fracture Mechanism
Compression 1
Burst 2
Rotational 3
Distraction 4
Neurologic Involvement
Intact 0
Nerve root 2
Cord & Conus
Complete 2
Incomplete 3
Conus 3
Posterior Ligament Complex
Intact 0
Indeterminate 2
Injured 3
Conservative < 4 points
4 points:
Indeterminate
> 4 points - Operate

13. Overview of Spine Trauma Classification AOSpine TLICS Classification
2013
AO Spine TLICS Classification
TLICS
AO (Magerl)
The reproducibility and feasibility of evaluating PLC integrity using magnetic resonance imaging (MRI) has been questioned.13,14 Also, the chosen severity scoring system guiding treatment may be a culture- or region-specific decision and may not reflect global surgical preferences or the most rational approach to treatment.
The AOSpine Trauma Knowledge Forum, an international group of academic spine surgeons, was tasked to develop and validate a classification system incorporating both fracture morphology and clinical factors relevant for surgical decision making, such as the presence of neurological deficits. The goal of this effort was to develop a widely accepted, comprehen- sive yet simple classification system with clinically acceptable intra- and interobserver reliability to be used for clinical prac- tice and research purposes.
agerl classification using an AOSpine database of more than 750 spinal trauma case
In 2013 the AO Spine Trauma Knowledge Forum combined TLICS with a revised Magerl classification to produce a comprehensive and simple classification scheme

14. Overview of Spine Trauma Classification AOSpine TLICS Classification
2013
Type A. Vertebral body compression
A1 Single Endplate
A2 Pincer
A3 Incomplete Burst
(Single endplate + Posterior wall)
A4 Complete Burst
(Both endplates + Posterior wall)
Type B. Failure of the posterior or anterior tension band
B1 Posterior Osseus Tension Band
B2 Posterior Ligamentous Tension Band
B3 Anterior Tension Band
Type C. Distraction, leading to failure of all elements leading to dislocation or
displacement in any plane
There are no subtypes
Clinical Status
N0 Neurologically intact
N1 Transient neurological deficit
N2 Symptoms or signs of radiculopathy
N3 Incomplete spinal cord injury or cauda equina injury
N4 Complete spinal cord injury

15. Examples by mechanism
Mechanism of injury describes the mechanical mode of failure.
Benefits: Knowing mechanism may help classify
Limitations of mechanisms:
Does not alone determine stability
Exact mechanism may sometimes be unknown

16. Examples Axial loading with Flexion (Compression)
Axial loading with flexion generally leads to compression injury (Type A fractures)
Most common type, accounting for up to 90% of cases.
The anterior column is compressed, with variable involvement of the remaining middle and posterior column
Compression: Axial loading + Flexion
Patient 1:
26 year old female in MVA.
Sagittal CT demonstrates an anterior compression fracture at T3.

17. Examples Axial loading with Flexion (Compression)
Patient 2
Sagittal T2 of the thoracic spine demonstrates a compression fracture with single endplate involvement.
A1: Single endplate (Green Arrow)
B0: Tension bands Intact (Curved Arrow)
C0: No Distraction (White arrowhead)
Compression: Axial loading + Flexion

18. Examples Axial loading with Flexion (Compression)
Patient 3:
Sagittal CT of the thoracic spine demonstrates a compression fracture with single endplate involvement.
A1: Single endplate (Green arrows)
Patient 3
Sagittal T2 of the thoracic spine demonstrates a compression fracture with single endplate involvement as well as disruption to the posterior band.
A1: Single endplate (Green arrows)
B2: Disruption of posterior tension band (Curved yellow line)
C0: No Distraction (Red lines)
Compression usually from axial + flexion
However, not all compression fractures are created equal.

19. Examples Compression with Axial loading (Burst)
Patient 4:
Axial and sagittal CT of the thoracic spine demonstrates an incomplete burst fracture (only superior endplate involved), A3
Axial compression generally leads to a burst injury, which may be incomplete (A3) or complete (A4).
Typically high energy trauma (i.e. fall from height)
Most commonly at the thoracolumbar junction and between T5 through T8.

20. Examples Compression with Axial loading (Burst)
Patient 5:
Axial and Sagittal CT of the thoracic spine demonstrates a complete burst fracture, involving both endplates as well as the posterior wall.
A4: Complete Burst Fracture

21. Examples Compression with Axial loading (Burst)*
Patient 5
Sagittal T2 of the thoracic spine demonstrates a compression fracture with both endplates involved.
A4: Both superior and inferior endplate involvement
B0: Tension bands Intact (Curved Arrow)
C0: No Distraction

22. Examples Compression with Axial loading (Burst)*
Historically, the Denis classification would consider this a two column injury (anterior and middle), which is unstable.
However, MRI reveals that the posterior and anterior tensor bands are maintained

23. Examples Distraction
Patient 6:
Sagittal CT and MR reveals complete failure of all elements leading to
Displacement (Type C injury)
Distraction results from separation of the adjacent vertebral bodies.
High chance of cord injury once supporting structures (osseous and ligamentous) are pulled separated.
While the appearance may be variable, there is no subtype
A distraction injury is separation or pulling apart of two adjacent vertebrae.
It is a severe injury since there is a high chance of cord injury when its osseous and ligamentous supporting structures are pulled apart.

24. Examples Distraction
Patient 7
Sagittal T2 demonstrates complete separation between the thoracic vertebral bodies and ligamentous structures.
A0: No compression deformity
B: Anterior and Posterior tensor bands are disrupted
C: Traumatic anterolisthesis
29 year MVA

25. Post Quiz #1 Which of the following is true regarding this injury?
The most common type of compression deformity
Results from vertical separation
Universally unstable
Most commonly located at the thoracolumbar junction

26. Post Quiz #1 Which of the following is true regarding this injury?
The most common type of compression deformity
Results from vertical separation
Universally unstable
Most commonly located at the thoracolumbar junction
Explanation:
Depicted is a burst fracture, which is most commonly located at the thoracolumbar junction (Choice D). Briefly, single endplate compression fractures are the most common (Choice A). Distraction injuries arise from separation (Choice B). Lastly, not all burst fractures are unstable (Choice C).

27. Post Quiz #2 Which of the following is true regarding this injury?
There are multiple subtypes given variability of this injury.
High likelihood of cord injury.
Results from axial loading.
Can often be managed conservatively.
Explanation:
Depicted is a distraction injury fracture, which is commonly associated with cord injury (Choice B). Briefly, while there is high variability, these are all considered Type C and there is no subtype. Distraction injuries arise from separation (Choice B). Lastly, distraction injuries are generally unstable (Choice D).

28. References
Bohler L. Die techniek de knochenbruchbehandlung imgrieden und im kriege. Verlag von Wilhelm Maudrich 1930 (in German)
Watson - JonesS. The results of postural reduction of fractures of the spine. J Bone Joint Surg Am, 1938 Jul; 20 (3):
NICOLL EA. Fractures of the dorso-lumbar spine. J Bone Joint Surg Br Aug;31B(3):
Holdsworth F. Fractures, dislocations, and fracture-dislocations of the spine. J Bone Joint Surg Am Dec;52(8):
Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976) Nov-Dec;8(8):
Baker AD. Classic Papers in Orthopaedics (2013). The Three Column Spine and Its Significance in the Classification of Acute Thoracolumbar Spinal Injuries. pp
Magerl F. A comprehensive classification of thoracic and lumbar injuries. Eur Spine J. 1994;3(4):
Parizel PM, van der Zijden T, Gaudino S, et al. Trauma of the spine and spinal cord: imaging strategies. Eur Spine J Mar;19 Suppl 1:S8-17.
Using the popular Denis three-column classification may lead to another situation since it uses the terms stable and unstable. In many cases, however, there is no good correlation with the necessity for surgery.