This document discusses the classification and treatment of thoracolumbar fractures using Denis' three column model. It describes minor injuries involving one column and major fractures involving failure of two or more columns. Treatment depends on the stability of the injury, with unstable injuries often requiring surgery and stable injuries treated initially with immobilization. Surgical indications include neurologic deficit, significant kyphosis, canal compromise, or progressive deformity.

1. Thoracolumber Fractures
Farhad Hussain
8/06/2018

2. Three Column Model
• Denis’ 3 column model of the spine attempts to identify CT criteria
of instability of thoracolumbar spine fractures.
• This model has generally good predictive value.

3. Anterior column:
• Anterior half of disc and vertebral body (VB) (includes anterior anulus fibrosus
(AF))
• Plus the anterior longitudinal ligament (ALL)
Middle column:
• Posterior half of disc and vertebral body (includes posterior wall of vertebral
body and posterior AF),
• Posterior longitudinal ligament (PLL)
• Pedicles
Posterior column:
• Posterior bony complex (posterior arch) with interposed posterior
ligamentous complex (supraspinous and interspinous ligament, facet joints
and capsule, and ligamentum flavum (LF)).
• Injury to this column alone does not cause instability

4. Classification
Minor injuries:
• Involve only a part of a column and do not lead to acute instability
(when not accompanied by major injures). Includes:
1. fracture of transverse process: usually neurologically intact except in
two areas:
a) L4–5 →lumbosacral plexus injuries (there may be associated renal injuries,
check U/A for blood)
b) T1–2 →brachial plexus injuries
2. fracture of articular process or pars interarticularis
3. isolated fractures of the spinous process: in the TL spine: these are
usually due to direct trauma.
• Often difficult to detect on plain x-ray
4. isolated laminar fracture: rare. Should be stable

5. Major Fractures
• The McAfee classification describes 6 main types of
fractures.2 A simplified system with four categories
• Type 1: Compression fracture: compression failure of
anterior column. Middle column intact
• (unlike the 3 other major injuries below) acting as a
fulcrum,
1. 2 subtypes:
a) anterior: most common between T6-T8 and T12-L3
● lateral x-ray: wedging of the VB anteriorly, no loss of
height of posterior VB, no subluxation
● CT: spinal canal intact. Disruption of anterior end-plate
b) lateral (rare)
2. clinical: no neurologic deficit

6. Burst Fractures
• Pure axial load →compression of vertebral
body →compression
• Failure of anterior and middle columns.
• Occur mainly at TL junction, usually between
T10 and L2.

9. Radiology
a) Lateral x-ray:
– Cortical fracture of posterior VB wall
– Loss of posterior VB height
– Retropulsion of bone fragment from
end plate(s) into canal

10. Radiology
b) AP x-ray:
• Increase of interpediculate
distance (IPD)
• Vertical fracture of lamina
• Splaying of facet joints: ↑
IPD indicates failure of
middle column

11. Radiology
c) CT: demonstrates break in
posterior wall of VB with
retropulsed bone in spinal
canal (average: 50%
obstruct ion of canal area),
increase in IPD with splaying
of posterior arch (including
facets)

13. Radiology
• d) MRI: compromise of anterior canal
by bone fragment; possible cord
compression usually with fragments
occupying > 50% of the canal diameter

15. Clinical
• clinical: depends on level (thoracic cord more sensitive and less
room in canal than conus region), the impact at the time of
disruption, and the extent of canal obstruction
a) ≈ 50% intact at initial examination (half of these recalled leg
numbness, tingling, and/or weakness initially after trauma that
subsided)
b) of patients with deficits, only 5% had complete paraplegia

16. Seat belt Fractures
• flexion across a fulcrum anterior to the anterior column (e.g. seat belt)
→compression of anterior column & distraction failure of both middle
and posterior columns.
• May be bony or ligamentous

18. Fracture-dislocation
• failure of all 3 columns due to compression, tension, rotation or
shear →subluxation or dislocation
3 subtypes
• a) flexion rotation: posterior and middle columns totally
ruptured, anteriorly compressed → anterior wedging
● lateral x-ray: subluxation or dislocation. Preserved posterior
VB wall. Increased interspinous distance
● CT: rotation and offset of VBs with →canal diameter.
Jumped facets
● clinical: 25% neurologically intact. 50% of those with deficits
were complete paraplegics

19. b) shear: all 3 columns disrupted (including ALL)
• when trauma force directed posteriorly to anteriorly (more common) VB
above shears forward fracturing the posterior arch (→free floating lamina)
and the superior facet of the inferior vertebra
• clinical: all 7 cases were complete paraplegics
c) flexion distraction
• radiographically resemble seat-belt type with addition of subluxation, or
with compression of anterior column >10–20%
• clinical: neurologic deficit (incomplete in 3 cases, complete in 1)

21. Associated injuries
• vertebral end-plate avulsion, ligamentous injuries, and hip
and pelvic fractures.
• Thoracolumbar fractures may be associated with
hemodynamic instability as a result of hemothorax or aortic
injury.
• Fractures of the transverse processes may be associated with
abdominal trauma (e.g. renal injuries at L4–5).

22. Stability and treatment of thoracolumbar spine
fractures
Minor injuries
• Isolated thoracolumbar transverse process fractures (as
demonstrated on spinal CT) do not require intervention or
consultation of a spine service.
Major spine injuries
Denis categorized the instability as:
1st degree: mechanical instability
2nd degree: neurological instability
3rd degree: both mechanical & neurological instability

23. Anterior Column Injury
• Isolated anterior column injuries are usually stable
• Treat initially with analgesics and recumbency (bed-rest) for
comfort × 1–3 weeks
• Diminution of pain is a good indication to commence mobilization
with or without external immobilization (corset or TLSO× ≈ 12
weeks) depending on the degree of kyphosis
• Vertebroplasty (± kyphoplasty) may be an option
• Serial x-rays to rule-out progressive deformity

24. The following exceptions may be unstable (1st degree) and often require
surgery
Unstable compression fractures
1. a single compression fracture with:
a) loss of >50% of height with angulation (particularly if the anterior part
of the wedge comes to
a point)
b) excessive kyphotic angulation at one segment (various criteria are used,
none are absolute. Values quoted: > 30°, > 40°)
2. 3 or more contiguous compression fractures
3. neurologic deficit (generally does not occur with pure compression
fracture)
4. disrupted posterior column or more than minimal middle column failure
5. progressive kyphosis: risk of progressive kyphosis is increased when loss of
height of anterior vertebral body is >75%. Risk is higher for lumbar
compression fractures than thoracic

25. Middle Column Failure
• These are unstable (often requiring surgery) with the
following exceptions which should be stable
Stable middle column fractures
• Above T8 if the ribs and sternum are intact (provides anterior
stabilization)
• Below L4 if the posterior elements are intact
• Chance fracture (anterior column compression , middle
column distraction)
• Anterior column disruption with minimal middle column
failure

26. Posterior Column Disruption
• Not acutely unstable unless accompanied by failure of the
middle column (posterior longitudinal ligament and posterior
anulus fibrosus). However, chronic instability with kyphotic
deformity may develop (especially in children).

27. Seat-belt type injuries without neurologic
deficit
• No immediate danger of neurologic injury. Treat most with external
immobilization in extension (e. g TLSO).

28. Fracture-dislocation
Unstable. Treatment options:
1. surgical decompression and stabilization: usually needed in
cases with
a) compression with >50% loss of height with angulation
b) or, kyphotic angulation >40° (or >25%)
c) or, neurologic deficit
d) or, desire to shorten length of time of bedrest
2. prolonged bedrest: an option if none of the above are present

29. When vertebral body resection (vertebral corpectomy) is
performed, options to access: transthoracic or
transabdominal approach (or combined), transpedicular (for
thoracic spine), lateral (retroperitoneal/ retropleural)
approach.
Fracture and compression usually occurs at the superior margin
of vertebral body, thus start resection at the inferior disc
interspace. Followed by strut graft (cage or bone: iliac crest or
fibula or tibia). Posterior instrumentation is usually required

30. Burst fractures
• Not all burst fractures are alike.
• Some burst fractures may eventually cause neurologic deficit (even
if no deficit initially).
Surgical indications for burst fractures: burst fracture with any of the
following:
• Anterior vertebral body height ≤50% of the posterior height
• Residual canal diameter ≤50% of normal
• Kyphotic angulation ≥ 20°
• When the increased interpediculate distance usually present on the
initial film widens further on AP x-ray when standing in brace/cast
• Neurologic deficit (incomplete)
• Progressive kyphosis

31. Common surgical options for burst or severe compression fractures:
1. If instrumentation alone is needed
A) can place pedicle screws in 2 levels above and 2 levels below the
fracture
B) if the index level can be included (i.E. If the pedicles are intact
enough to accept shorter screws), similar biomechanical stability
can be achieved by placing screws at the index level (the fractured
level) and then just 1 above and 1 below

32. 2. If decompression of the spinal canal and/or anterior support is
needed, corpectomy and strut graft (e.g. with expandable cage)
with percutaneous pedicle screws may be used.
Approaches:
a) from posterior approach e.g. laminectomy with transpedicular
approach and impacting bone anteriorly out of canal with a mallet
and reverse angled curette, or
b) lateral corpectomy and removal of bone from canal

33. • For those not undergoing surgery (i.e. when surgery is not required
or is contraindicated), an option is to treat with recumbency from
1–6 weeks (the duration depending on pain and degree of
deformity).
• Avoid early ambulation →further axial loading (even in cast). When
appropriate, begin ambulation in an orthosis (e.g. molded
thoracolumbar sacral orthosis (TLSO) and follow patient for 3–5
months with serial x-rays to detect progressive collapse or
angulation which may need further intervention.

34. Thoracolumbar injury classification and
severity score (TLICS)
• The TLICS system has been proposed to simplify classification an d
discussion of thoracolumbar fractures.
• Points are assigned, the scores are summed, and management
guidelines are given.
• Neurologic deficit, especially when partial, favors surgery.

37. Surgical Treatment
Burst Fractures
Choice of Approach:
• Surgical considerations: a posterior approach is preferred if there is
a dural tear, whereas a burst fracture with partial deficit and canal
compromise may be treated more effectively from an anterior
approach.
• A small progression in angular deformity may occur when posterior
stabilization is performed alone (since the injury to the anterior
column is not corrected), but by itself usually does not require
intervention.

38. For a posterior approach
• In ideal situation (good bone quality, pedicle screw placement goes
well (i.e. no fracture, no breach), and non-smoking patient) then
one can fuse/rod one above and one below the fracture (using
pedicle screws; longer constructs are needed with laminar hooks).
• With a short segment fusion like this, approximately 10° of lordosis
be lost with time, therefore, one should try to overcorrect a little to
accommodate the anticipated settling.

39. • If the patient does not meet the above criteria (e.g. poor bone quality),
an option is to “rod long, fuse short” (e.g. rod 2 levels above and
below the fracture but fuse only 1 level above and below)
• Remove the hardware when the fusion is solid (e.g. at 8–12 months) –
this avoids fusing a nonpathologic segment just to get a better anchor.
• Fusing across critical levels (i.e. thoracolumbar junction with T11 or L1
compression fractures) requires that the fusion incorporate 2–3 levels
on each side of the junction (the forces of the long segment of the
relatively immobile thoracic spine with the lumbar spine at the T-L
junction increase the risk of nonunion)

40. Wound infections
• Postoperative wound infect ions with spinal instrumentation are
usually due to Staph. aureus.
• With titanium hardware it may respond to debridement of
devitalized tissue and thorough washout (typically with 3 L of
antibiotic irrigation flushed into the wound using a pulse lavage
device – avoiding direct irrigation of any exposed dura) without
removal of instrumentation, followed by antibiotics.
• Persistent infection may respond to. If this is inadequate, removal
of instrumentation may occasionally be required

41. Thank You