Traumatic Thoraco-Lumbar FracturesRobert Lieberson, MDNeurosurgery

The theme of this lecture is:

50% - 50% - 30⁰

Se-ries1

And:• Three column injury (with exceptions)• Neurologic deficit and ongoing

compression• Ligamentous injury involving 2 or 3

column (distraction, locked facets)• Progressive deformity (i.e. fails brace)

• Anterior vs. posterior surgery—go for the pathology

Outline• Background• ACS trauma protocol (ATLS)• Biomechanics• Definitions• How to grade a spinal injury

• Instability • Treatment

• Questions

Background—history • Edwin Smith Papyrus describe the diagnosis treatment for the spine and spinal injuries (Egypt, 2500 BCE to 1900 BCE)• Hippocrates (400 BCE) described a thoracic fracture and recommended reducing the gibbus using a racklike traction device (scamnum) • An alternative was "succussion" which consisted of tying the patient upside down to a ladder-like device that was suddenly dropped• In the seventh century, Paulus of Aegina suggested laminectomy to debride the fracture site—probably not done in his lifetime 

Background—demographics

• Thoracic and lumbar fractures—30% to 50% of all spine fractures

• 15,000 annually in the United States

• > 50% of thoracic and lumbar fractures between T11 and L1

• 15% to 20% are associated with neurological deficits

ATLS Evaluation—spine patient

1. Primary Survey—• ABCDEs

2. Secondary Survey—• General exam• Ortho exam• Neuro exam (including GCS)

3. Tertiary Survey—1. PMH2. Meds, 3. Allergies …

Primary survey—ABCDE (different than the ABCs of CPR)• Should arrive in a collar and on a board

• Airway (remember the c-spine precautions)• Breathing (exclude pneumothorax, tamponade, etc.)

• Circulation (and also control hemorrhage)• Disability/neurological (AVPU [alert, verbal,

painful, unresponsive], pupils and spinal cord (GCS goes with secondary survey)

• Environmental (remove clothes, correct/prevent hypothermia)

C

Secondary Survey• Complete history• GCS • Ortho

• Inspection• Palpation

• Neuro exam• Neurological Evaluation• Sensory, motor, and reflexes—including

bulbocavernosus and rectal tone• ASIA Impairment Scale

Secondary Survey• X-rays and lab• Focused abdominal sonogram for trauma

(FAST exam)—evaluates pericardium, abdomen and pelvis for blood

• CBC, BMP, coags, type and screen, tox, ABG, pregnancy

• CTs of C-spine, chest, abdomen, and pelvis

• Keep PaO2 > 60 mm Hg, SBP ≥ 65 mm Hg

Of patients with one spine fracture:• 28% have other major organ system

injuries (Meyer, 1984)• 15% (3%-56% have non-

contiguous spine fractures)• Obtunded patients require further

skeletal survey (Mackersie, 1988) • Hemorrhage common from other sites• Hypotension if spinal cord injury• Foley recommended• Ileus common

C3,4,,5—keeps the diaphragm aliveT1 to T12—intercostal muscles • SCI patients often require intubation

T1—stellate ganglion

• SCI patients often hypotensive

Other• AS/DISH/Metabolic bone disease • Sternal fracture • Multiple rib fractures at same or

adjacent levels as fracture • Burns at site of anticipated

incision site

Tertiary Survey• PMH, Meds, Allergies, FH, SH, ROS• Serial assessments, • Rate of delayed diagnosis can be

10%

If patient deteriorates, return and repeat the primary survey

Biomechanics—force vectors• Forces acting on the spine can be broken down into

component vectors• Each vector has a magnitude and a direction

Biomechanics--moment arm• “Give me a lever arm long enough, and a fulcrum on which

to place it, and I shall move the world”— Archimedes

• Forces acting directly on a point cause translation• Forces acting through a lever (a moment arm) cause

rotation about an axis (and multiply the force)• A rotational force is a “bending moment”• The fulcrum is the “instantaneous axis of rotation” or “IAR”

Moment arm determines fracture type

• The “IAR” normally lies within the posterior half of the vertebral body (except in pathologic states like scoliosis)

• The magnitude of the moment arm is calculated as the product of force and distance (M = F x D)

Biomechanics—Hook’s Law• Bone is not an ideal material.• A-B small forces, substantial

flexibility—“neutral zone”• B-C deformation proportional

to deforming force—“elastic zone” or “ideal zone”

• C “elastic limit”• C-D larger force—permanent

deformation: “plastic zone”• D “point of failure”

B

CD

Biomechanics—instability • When the addition of a small load results in

• a large, catastrophic displacement• a deformation much greater than normal

• The stress exceeds the “point of failure”• “The inability of the spine under physiologic loads to

maintain relationships between vertebrae such that there is neither acute nor subsequent neurologic injury, deformity or pain.” (White and Panjabi)

At the moment of injury

Biomechanics—spine fracture• In normal, the fulcrum is in the

middle column.• The body’s weight is centered

over the hip joints• At each spinal level there is a

fixed displacement from the axis (or moment arm)

Biomechanics—spine fracture

• T1-T8 • Rigid (rib cage)• Kyphosis• Flexion injuries predominate

• T9-L2• Straight• Transition: immobile—mobile• Transition: kyphosis—lordosis• Most injuries here

• L3-Sacrum• Mobile• Lordosis• Axial loading injuries predominate

Biomechanics—T1-T8

• In the upper thoracic spine, the center of gravity is anterior

• Axial loading causes compression anteriorly and distraction posteriorly

• Flexion injuries—i.e. wedge

Biomechanics—T9-L2• The thoraco-lumbar spine is one of

the most mobile segments• Subject to compression, flexion,

extension, rotation• Relatively straight and sandwiched

between a kyphotic and a lordotic area

• Little opportunity to disperse the forces

• Junction of stable thoracic and mobile lumbar spine (stress riser)

• Facet joints less protective due to intermediate orientation between coronal (thoracic spine) and sagittal (lumbar spine)

Biomechanics—L3-Sacrum

• In the lumbar spine, the center of gravity is posteriorly

• Flexion straightens the lordosis and causes axial loading

• Burst fractures predominate

Biomechanics—coupling• The spine is balanced in three

dimensions• If there is a shift in one area, there

must be a compensatory shift in the opposite direction in another

• “Coupling” explains the compensatory curves seen in scoliosis

Definitions—Compression fractures• There are three types of compression

fractures: • Wedge fracture

• most common type• Anterior compression (posterior intact,

wedge shape) • usually stable • can lead to deformity such as kyphus

• Crush fracture• involves anterior and posterior portions of

vertebra• usually mechanically stable.

• Burst fracture• violates posterior margin• may compress spinal cord• more likely unstable

Definitions—pincer fracture

Definitions—vertebra plana

• Vertebra plana, ”pancake vertebra,” vertebral body has lost almost its entire height. • trauma• osteoporosis• Langerhans cell histiocytosis (LCH)• osteogenesis imperfecta• leukemia• vertebral metastases• multiple myeloma• lymphoma• osteomyelitis• vertebral hemangioma

Definitions—hemivertebra

• vertebral anomaly which results from the lack of formation of one half of a vertebral body

• common cause of congenital scoliosis

Definitions—block vertebra

• vertebral anomaly where there is a failure of separation of two or more adjacent vertebral bodies

• AKA vertebral synostosis

• In the neck, Klippel-Feil

Definitions—butterfly bertebra

• vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochord between them

Definitions—1½ Vertebra

• Three pedicles (a vertebra plus a Hemivertebra)

• Any combination is possible (i.e. 1+ two ½s, 2½, 3½, etc.)

Definitions—transitional vertebra

• Occurs at the junction between spinal segments• atlanto-occipital junction

• atlanto-occipital assimilation: complete or partial fusion of C1 and the occiput

• occipital vertebra: an additional bone between C1 and the occiput

• cervicothoracic junction• cervical rib arising from C7

• thoracolumbar junction• 13th rib arising from T13 or L1 (depending on

numbering)• lumbosacral junction

• lumbosacral transitional vertebra: most common

Definitions—ankylosing spondylitis

• AKA Bechterew disease and Marie Strümpell disease

• results in fusion of the spine, sacroiliac (SI) joints, and other large and small joints

• rheumatoid factor (RF) negative (seronegative)

• 90% of Caucasian individuals have the HLA-B27 gene  

The theme of this lecture is:

50% - 50% - 30⁰

Se-ries1

And:• Three column injury (with exceptions)• Neurologic deficit and ongoing

compression• Ligamentous injury involving 2 or 3

column (distraction, locked facets)• Progressive deformity (i.e. fails brace)

• Anterior vs. posterior surgery—go for the pathology

Grading of spine fx—many systems

• Morphology (bony/ligamentous) • Mechanism (biomechanical)• Radiographic (CT or MRI findings)• Clinical (neurological injury)

Evolution of T-L Classifications

2010200019901980197019601950194019301920

CT Developed

MRI Developed

Pedicle Screws

Boehler

(1929

) W

atson-Jo

nes (1

938)

Nicoll (

1949

) Hold

swor

th (1

963)

Roy-C

amille

(197

9)

Denis

(1983

) AO-M

ager

l (199

4)

The T

L Inju

ry Se

verit

y

Class

/ Vac

caro

(200

5)

3-Col ModeMorphologic Classif 2-Column Model

Boehler (1929) • First attempt to define instability• Based only on mechanism• Five types (compression, flexion-distraction,

extension, shear, rotation)

Watson-Jones (1938)• 252 patients• Built on Boehler--Mostly mechanistic• Recognized importance of PLL• Seven types in three groups (simple wedge,

comminuted fractures, fracture dislocations)

Nicoll (1949) • 152 patients• Refined the anatomic classification• Four critical structures (body, disc, facets, intraspinous

ligament)• Said intraspinous ligament the main determinant of

stability

Holdsworth (1963)• Introduced the concept of a two-column

model• Anterior column (PLL, body, ALL)• Posterior column (facets, intraspinous

ligament)

Kelly and Whitesides (1968)• Attempted to redefine Holdsworth• Redefined anterior column as the body• Posterior column as neural arch and posterior elements• Basis for Denis and McAfee

Louis (1977) • Introduced first three-column system • anterior column, and the two posterior columns

consisting of the row of facet joints [• Called a “trepied” concept.

Roy-Camille (1979)• Discussed the importance of the base of the fracture, the “ségment vertrébral moyen” or “average spinal segment”• Classification not widely used• 1970, Roy-Camille, described the use of posterior plates with screws through the pedicles• 1982, Steffee developed a

pedicle screw used from lower T-spine to the sacrum

Three-column model—Francis Denis (1983)• Based on Holdsworth (1963)

2-column model and Louis (1977) 3-column model

• 412 fractures• Pros—easily understood,

commonly used• Cons—does not account for

neurological status or ligamentous support

Denis—three columns• Posterior column = Posterior

arch + supraspinous ligament + interspinous ligament + ligamentum flavum

• Middle column = Posterior longitudinal ligament + posterior vertebral wall + posterior annulus fibrosus

• Anterior column = Anterior longitudinal ligament + anterior annulus fibrosus + anterior vertebral body Anterior Middle Posterior

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

Denis—Stability

• Denis concept of stability• Stable fractures (minimal to moderate

compression, early ambulation with or without immobilization)

• First degree instability (severe compression or seat-belt injury, mechanical instability)

• Second degree injury (neurologic instability)• Third degree injury (mechanical and

neurologic instability)

Denis—Major vs. Minor

• Minor injuries • Fracture of transverse process• Fracture of articular process• Fracture of pars-intra-articularis• Isolated spinous process fracture

• Major injuries • Compression fracture (compression of anterior column only)• Burst fracture (compression of anterior and middle column,

retropulsion)• Seat-belt-type injury (distraction of middle and posterior

columns)• Fracture dislocation (three column failure, multiple force

vectors)

Denis—modes of failure

TypeAnterior Column

MiddleColumn

PosteriorColumn

Compression Compression None None or distraction (severe)

Burst Compression Compression None or splaying of pedicles

Flexion-Distraction None or distraction

Distraction Distraction

Fracture/Dislocation Distraction

Fracture/Dislocation Rotation Rotation Rotation

Fracture/Dislocation Shear Shear Shear

Each fracture defined by the effect on each of the columns. The location of the fulcrum, at the instant of the injury, is critical.

Yellow is the location of the fulcrum

Compression Distraction

} (FULCRUMOUTSIDEOFSPINE)

Denis—for example

TypeAnterior Column

MiddleColumn

PosteriorColumn

Compression Compression None (FULCRUM)

None or distraction (severe)

The fulcrum is the center of rotational component.

• Structures in front of IAR are compressed• Structures behind are stretched• Least damage at the location of the fulcrum.

McCormack (1994)• 28 patients between 1986 and 1991• Load sharing concept using CTs and plain radiographs• Focuses on ability of the fracture to support any load• Less interested in the ligamentous injury

• Can be used preoperatively to: • predict screw breakage when short segment,

posteriorly placed pedicle screw implants are used• describe any spinal injury for retrospective studies• select spinal fractures for anterior reconstruction with

strut graft, short-segment-type reconstruction• A point system (the load sharing classification)

• the amount of damaged vertebral body• the spread of the fragments in the fracture site• the amount of corrected traumatic kyphosis

• In the absence of “load sharing,” failure of short construct pedicle screws more likely—use longer segment poster fusion or anterior construct or both

• based on  Denis and  McAfee

• Relies on CT findings

• A: Compression/ anterior failure

• B: Distraction/ posterior failure

• C: Rotation/ anterior and posterior failures

• Three classification levels (e.g. A3.3.3)

Magerl-AO (1994)Arbeitsgemeinschaft für Osteosynthesefragen

Magerl-AO (continued)• based on more than

1,400 fractures• Type A, B and C each

divided to three Groups for nine basic injury types

• sub-divided in totally 27 different injuries

• Type A—65% of thoracolumbar injuries

• Type B—15% • Type C—20%

Magerl-AO (continued)• Severity determined

by amount of bony, ligamentous or combination of both plus neuro-damage and mechanical instability

• Increasing degree of severity from A to C and 1 to 3

• Groups are overlapping

AO-Magerl (continued)• A: compression injuries• A1: impaction fractures

• A1.1: endplate impaction• A1.2: wedge impaction• A1.3: vertebral body collapse

• A2: split fractures• A2.1: frontal split fracture• A2.2: sagittal split fracture• A2.3: pincer fracture

• A3: burst fractures• A3.1: incomplete burst fracture• A3.2: burst split fracture• A3.3: complete burst fracture

A3.3.1: pincerA3.3.2: flexionA3.3.3: axial

• B: distraction injuries• B1: predominantly transligamentous flexion-

distraction injury• B1.1: with transverse disc disruption

B1.1.1: flexion subluxationB1.1.2: anterior dislocationB1.1.3: B1.1.1 or B1.1.2 the with fractures of the articular processes

• B1.2: with type A vertebral body fracture

• B2: predominantly osseous flexion-distraction injury• B2.1: transverse bicolumn fracture• B2.2: posterior osseous disruption with

transverse disc disruptionB2.2.1: through the pediclesB2.2.2: through the interarticular portions (flexion spondylolysis)

• B2.3: with type A vertebral body fractureB2.3.1: through the pediclesB2.3.2: through the isthmus

• B3: anterior disruption through the disc• B3.1: hyperextension-subluxation• B3.2: hyperextension-spondylolysis• B3.3: posterior dislocation

• C: torsion injuries• C1: rotation-compression injury

• C1.1: impaction• C1.2: split• C1.3: burst

• C2: rotation-distraction injury• C2.1: with transligamentous flexion-

distraction• C2.2: with transosseous flexion-distraction• C2.3: with hyperextension-distraction

• C3: rotational shear injury

AO-Magerl (continued)

• Pros• Very detailed• Considers both fracture pattern and mechanism

• Cons• Overly complex• Not reproducible• Does not account for neurological status

Vaccaro (2005)—Thoracolumbar Injury Classification and Severity score (TLICS) 

• Morphology    • compression fracture - 1

point • burst fracture - 2 points• translational rotational

injury - 3 points• distraction injury - 4

points• Posterior ligamentous

complex• intact - 0 points• suspected injury or

indeterminate - 2 points• injured - 3 points

• Neurologic involvement• intact - 0 points• nerve root - 2 points• cord/conus

medullaris (incomplete) - 3 points

• cord/conus medullaris (complete) - 2 points

• cauda equina - 3 points

> 4 points - OperateConservative < 4 points 4 points:Indeterminate

AO Spine-TLICS Classification (2013)

AO Spine TLICS

Classification

TLICS AO (Magerl)

In 2013 the AO Spine Trauma Knowledge Forum combined TLICS with a revised Magerl classification to produce a comprehensive and simple classification scheme

Type A. Vertebral body compressionA1 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 StatusN0 Neurologically intactN1 Transient neurological deficitN2 Symptoms or signs of radiculopathyN3 Incomplete SCI or cauda equina injury N4 Complete spinal cord injury

AO Spine-TLICS (Continued)

The management of thoraco-lumbar injuries is Controversial

• No universally accepted definition of “stable”• Surgeons disagree on if/when to do surgery• Surgeons disagree on if/when/how long to

brace

Non-operative treatment of T-L fractures• Brace or cast

• Compression fractures• Stable burst fractures• Pure bony flexion-distraction injuries

• Injuries from T4 to T8 stabilized by the ribs—less likely to need surgery

Bracing for wedge or burst fractures

Some wedge compression / burst fractures may be treated conservatively

• Brace if < 50% compressed, < 50% in canal, and < 30⁰ Cobb angle

• Bed rest followed by application an extension brace• Bracing does not prevent a kyphotic deformity or

improve the Cobb angle• Bracing may not improve pain• Bracing may cause worse scores on SF-36

Bracing

Operative treatment of T-L fractures

• Unstable burst fractures• Purely ligamentous• Facet dislocations• Translational injuries• Neurological deficit (especially incomplete)

The vast majority are stable and non-operative

• Surgery if > 50% compressed, > 50% in canal, or > 30⁰ Cobb angle

• Surgery if multiple contiguous compression fractures with and kyphosis > 60°

• Surgery if neurological deficit (especially incomplete)• Surgery if posterior ligamentous disruption

(Interspinous and interlaminal widening) or articular fractures

• Surgery if progressive deformity over time

Surgery for wedge or burst fractures

Anterior vs. posterior surgery

• Anterior• More predictable decompression• Saves levels• Questionable improved recovery• May improve bladder function

• Posterior• Less morbidity• Fails with short segment constructs—requires more

levels• Less blood loss• Transpedicular anterior column grafting may protect

the posterior construct

Why didn’t I discuss bending films

• Not a great deal of help in the thoraco-lumbar spine• Patients will have pain and changes on static laterals

long before bending films are helpful

The theme of this lecture is:

50% - 50% - 30⁰

Se-ries1

And:• Three column injury (with exceptions)• Neurologic deficit and ongoing

compression• Ligamentous injury involving 2 or 3

column (distraction, locked facets)• Progressive deformity (i.e. fails brace)

• Anterior vs. posterior surgery—go for the pathology

What is it?

CT scan—T12 burst fracture

45⁰

>50%

What is it?

MRI scan—T12 burst fracture

<50% >50%

What is it?

Distraction injury

What is it?

Dislocation

What is it?

Multiple adjacent compression fxs

What is it?

CT scan—L3 Chance fracture

L3 Chance fracture

MRI scan—L3 Chance fracture

Post-op—L3 Chance fracture

The theme of this lecture is:

50% - 50% - 30⁰

Se-ries1

And:• Three column injury (with exceptions)• Neurologic deficit and ongoing

compression• Ligamentous injury involving 2 or 3

column (distraction, locked facets)• Progressive deformity (i.e. fails brace)

• Anterior vs. posterior surgery—go for the pathology