Thoracic, Lumbar, Pelvic Trauma

Question 1

TL fracture stability

What are the three columns of the thoracolumbar spine?

Answer 1

Anterior: anterior 2/3 of vertebral body
Middle: posterior 1/3 of vertebral body
Posterior: posterior elements

Question 2

TL fracture stability

What is the 3 column theory of Denis?

Answer 2

• Fracture is stable if one column is affected e.g. compression
• Fracture is unstable is two or more columns are affected
• The middle column cannot fracture by itself

if it appears that only the middle column is fractured, it’s probably unstable

Question 3

TL fracture stability

What are the caveats to the 3 column theory of Denis?

Answer 3

• Traumatic posterior limbus bone is an exception to the middle column rule
• Anterior column involvement only, but >50% height loss is probably unstable e.g. burst or Chance

Question 4

The epidemiology of TL compression fractures consists of:

35%:
30%:
25%:

forget about the other 10%

Answer 4

35%: female >45yo w/ postemenopausal osteoporosis
30%: secondary osteoporosis
25%: acute trauma

Question 5

What are the mechanisms of TL compression fractures?

Answer 5

• Osteoporosis with minor trauma
• Insufficiency fracture
• Acute trauma: hyperflexion and/or axial load

Question 6

If there is a TL compression fracture due to flexion/axial load, the ___ of the vertebra is affected.

Answer 6

anterior body

Question 7

What are the most common sites for TL compression fracture?

Answer 7

T11-L1

Question 8

Most compression fractures are ___-shaped.

Answer 8

wedge

Question 9

Is neurological injury likely with compression fracture?

Answer 9

Rare

Question 10

What are the shapes of compression fracture that occur in the lower lumbar spine?

Answer 10

• Wedge
• Central endplate (vertebra plana)
• Biconcave

Question 11

What is the likely nature of the compression fracture if it is vertebra plana shaped/collapsed?

Answer 11

Osteoporotic/insufficiency pathological fracture

Question 12

Which compression fracture shapes are more likely to display step defect and/or paraspinal edema?

Answer 12

Wedge shaped

biconcave and vertebra plana usually do not have step defect or paraspinal edema

Question 13

What are the three most important factors in determining if a TL compression fracture is new or old?

Answer 13

• Zone of impaction
• Step defect
• Paraspinal edema

Question 14

If a wedge-shaped compression fracture has a zone of impaction, step defect, or paraspinal edema, it is assumed to be ___.

Answer 14

acute/new

Question 15

If a wedge-shaped compression fracture does not display a zone of impaction, step defect, or paraspinal edema, it is assumed to be ___.

Answer 15

either acute or old

characteristic are highly specific but not sensitive

Question 16

If abdominal ileus is present with a wedge-shaped compression fracture, is it more likely new or old?

Answer 16

New

Question 17

What feature of a wedge-shaped compression fracture is most indicative that it is old?

Answer 17

Disc degeneration

Question 18

If a wedge-shaped compression fracture has a positive bone scan, is it more likely new or old?

Answer 18

Not an indicative characteristic

bone scans can be positive 2+ years post fracture

Question 19

If a wedge-shaped compression fracture displays marrow edema on MRI, is it more likely new or old?

Answer 19

New

bone marrow edema on MRI is gone after 12 weeks

look at T2 or STIR for bright blood

Question 20

If a compression fracture is acute and stable, refer the patient to ___.

Answer 20

orthopedist

Question 21

Always rule out ___ and ___ fractures before diagnosing compression fracture.

Answer 21

burst and Chance fractures

Question 22

Burst fractures involve ___ columns making them ___.

Answer 22

2-3 columns (typically 3) making them unstable

convex posterior element indicates a middle column fracture (unstable)

Question 23

What is the mechanism of burst fracture?

Answer 23

Axial compression with flexion

Question 23

Up to ___% of those with burst fracture will have neurological injury.

Answer 23

50%

no spinal cord in lumbar, the cauda equina can move out of the way more

Question 24

Burst fractures may look like compression fractures. What are the possible additional findings that indicate burst fracture?

Answer 24

* Retropulsion of middle column body fragments * Vertical splitting of body * Comminution of body * Focal widening of interpedicle distance (indicates posterior element fracture)

Question 25

What is the appropriate followup for someone with a burst fracture?

Answer 25

* Stabilize patient for emergency transport (unstable fracture) * CT for osseous fragments * MRI useful for cord/nerve root damage

Question 26

Posterior limbus bones involve the ___ column(s) but is stable, making it an exception to the theory of Denis.

Answer 26

middle column ## Footnote **only** the middle column

Question 27

What is the greatest concern for a patient with a posterior limbus bone?

Answer 27

Neurologic compromise from stenosis

Question 28

What is the mechanism of a transverse process fracture?

Answer 28

Flank trauma (huge force) or extension with lateral flexion

Question 29

What is the second most common lumbar fracture?

Answer 29

Transverse process fracture

Question 30

What is the differential for a transverse process fracture?

Answer 30

Ununited TP ossification center

Question 31

Force to the flank must go through 2-3in of soft tissue before fracturing a lumbar transverse process. What organs are of biggest concern with this trauma?

Answer 31

Ureter or kidney damage (20% of cases) | with or without hematuria ## Footnote requires abdomen CT w/ IV contrast

Question 32

Transverse process fractures in the lumbar spine may lead to heterotopic ossification, and as a result ___.

Answer 32

lumbar osseous bridge syndrome (LOBS)

Question 33

What are the mechanisms of pars interarticularis fracture?

Answer 33

* Most are fatique fractures (with spondylolisthesis) * Acute trauma is **very** uncommon * Hyperextension injury

Question 34

Chance fracture is also known as ___

Answer 34

lap belt fracture

Question 35

What is the mechanism of Chance fracture?

Answer 35

Flexion and distraction over a fulcrum

Question 36

Why might Chance fracture be confused with simple compression?

Answer 36

Compression fracture of anterior body appears similarly

Question 37

Chance fracture involves horizontal splitting of:

Answer 37

* posterior vertebral body * spinous * pedicles

Question 38

What creates the empty vertbra sign demonstrated by Chance fracture?

Answer 38

Horizontal splitting of pedicles

Question 39

Is Chance fracture stable or unstable?

Answer 39

Unstable ## Footnote concerns for neurologic compromise and soft tissue

Question 40

What are the associated soft tissue injuries with Chance fracture?

Answer 40

* **Spleen** * Pancreas * Aorta * Viscera | due to abdominal trauma ## Footnote damaged/absent spleen leads to immune system compromise

Question 41

What are mechanisms of sacral fractures?

Answer 41

* Fall on buttocks (most common) * Direct trauma * Associated with pelvic trauma ## Footnote look carefully for other fractures

Question 42

What is the most common type of sacral fracture?

Answer 42

Horizontal/transverse fractures

Question 43

Horizontal sacral fractures are best seen on which view?

Answer 43

Lateral view | shows horizontal offset in sacrum ## Footnote often seen at 3rd and 4th sacral level below SI joint

Question 44

Is horizontal sacral fracture stable or unstable?

Answer 44

Isolated fracture is stable

Question 44

Horizontal sacral fractures can be hard to see, so it's important to look at the presacral space. This space should be ___ in children and ___ in adults.

Answer 44

<5mm in children <20mm in adults

Question 45

What is the mechanism of vertical sacral fractures?

Answer 45

Indirect trauma to pelvis

Question 46

What is the risk for organ damage if there is vertical sacral fracture?

Answer 46

50% will have pelvic organ damage

Question 47

Vertical sacral fractures are only visible on ___ view. What are the possible findings indicating vertical fracture?

Answer 47

only visible on **AP** view disruption or distortion of sacral foramina

Question 48

Most cocygeal fractures are ___ and best seen on ___ view.

Answer 48

**transverse** and best seen on **lateral** view | standing lateral

Question 49

Anterior displacement of the coccyx is common. What are other possibilities to look out for with coccygeal fractures?

Answer 49

May subluxate or dislocate sacrococcygeal joint ## Footnote assess instability with a seated flexion extension radiograph series

Question 50

# stability 2 disruptions in the main pelvic ring are ___. 2 disruptions in an obturator are ___.

Answer 50

main pelvic ring = unstable obturator = stable

Question 51

What is the term for an isolated iliac wing fracture through the fossa breaking off the crest?

Answer 51

Duverney fracture

Question 52

What is the mechanism of Duverney fracture?

Answer 52

Direct force to pelvis from lateral direction

Question 53

Is Duverney fracture stable or unstable?

Answer 53

Stable | ring not disrupted, will heal fine with minimal displacement

Question 54

What are the components of Malgaigne fracture?

Answer 54

3 components, all ipsilateral: * Inferior pubic ramus * Superior pubic ramus * Posterior arch (vertical sacral fracture, SI joint diastasis, or ilium fracture)

Question 55

What is the mechanism of Malgaigne fracture?

Answer 55

Vertical shearing forces on pelvis ## Footnote e.g. land on leg or one buttock

Question 56

Is Malgaigne fracture stable or unstable?

Answer 56

Unstable | multiple disruptions of ring

Question 57

What are the components of bucket-handle fracture?

Answer 57

3 components: * Inferior pubic ramus (ipsilateral) * Superior pubic ramus (ispilateral) * Posterior arch (contralateral) (vertical sacral fracture, SI joint diastasis, or ilium fracture) ## Footnote anterior ipsilateral, posterior contralateral

Question 58

___% of all pelvic fractures involve the acetabulum.

Answer 58

20%

Question 59

What is a dashboard fracture?

Answer 59

Posterior acetabular rim fracture

Question 60

What is an acetabular blowout fracture?

Answer 60

Central acetabular fracture

Question 61

What is the mechanism of dashboard fracture?

Answer 61

Flexion with abduction ## Footnote concave driven into convex and concave fails

Question 62

Is dashboard fracture stable or unstable?

Answer 62

Stable but associated with other concerns

Question 63

Dashboard fracture is stable, but what are some associated subsequent concerns?

Answer 63

* Femoral dislocation * Labral tear * Sciatic neuropathy due to piriformis

Question 64

What is the most common acetabular fracture? How is it sustained?

Answer 64

Acetabular blowout fracture Side impact force hits greater trochanter

Question 65

Is acetabular blowout fracture stable or unstable?

Answer 65

Unstable | multiple bones are likely broken

Question 66

What radiographic line will be abnormal with acetabular blowout fracture?

Answer 66

Kohler's line will go through the femoral head

Question 67

What is the most common form of unstable pelvic fracture?

Answer 67

Straddle fracture

Question 68

What is a straddle fracture?

Answer 68

Bilateral vertical fractures through both superior pubic rami and inferior ischiopubic rami | if unilateral, specify

Question 69

What are the complications experienced by 20% of patients with straddle fracture?

Answer 69

* Bladder rupture * Urethral tear

Question 70

What is pubic diastasis?

Answer 70

Separation of pubic articulation

Question 71

What are the normal maximum measurements for the separation between pubic articulations?

Answer 71

Non-pregnant adults: 8mm Children: 10mm | may be wider in pregnancy

Question 72

When pubic diastasis is identified, you must carefully scrutinize ___ for associated injuries.

Answer 72

SI joints and sacram (posterior column)

Question 73

Sprung pelvis is also known as ___.

Answer 73

open book pelvis

Question 74

What is the mechanism of sprung pelvis?

Answer 74

AP compression e.g. giving labor

Question 75

Is sprung pelvis stable or unstable?

Answer 75

Unstable

Question 76

What is the appropriate term if there is diastasis of symphysis pubis and diastasis of one or both SI joints?

Answer 76

Sprung pelvis

Question 77

Sprung pelvis has a strong association with ___ injury.

Answer 77

pelvic organ

Question 78

What are the components of sprung pelvis?

Answer 78

* Diastasis of symphysis pubis * Diastasis of one or both SI joints

Question 79

What is the appropriate term if there are bilateral vertical fracture through both superior pubic rami and inferior ischiopubic rami?

Answer 79

Straddle fracture | can be unilateral

Question 80

What are the mechanisms of pelvic avulsion fractures?

Answer 80

* Single episode of acute trauma * Repetitive chronic trauma

Question 81

Which patients most commonly experience pelvic avulsion fractures?

Answer 81

Adolescents and young adults ## Footnote e.g. sprinters, long jumpers, gymnasts, hurdlers, etc.

Question 82

If there is an ASIS avulsion fracture, the muscle responsible is ___.

Answer 82

sartorius

Question 83

If there is an AIIS avulsion fracture, the muscle responsible is ___.

Answer 83

rectus femoris

Question 84

If there is an ischial tuberosity avulsion fracture, the muscle responsible is ___.

Answer 84

hamstrings

Question 85

Why might someone have developed Riders bone?

Answer 85

Overgrowth of ischial tuberosity due to hamstring avulsion

Question 86

Where would the pelvic avulsion fracture be if sartorius is the cause?

Answer 86

ASIS

Question 87

Where would the pelvic avulsion fracture be if rectus femoris is the cause?

Answer 87

AIIS

Question 88

Where would the pelvic avulsion fracture be if hamstrings are the cause?

Answer 88

Ischial tuberosity