Sacral Fractures

1. SACRAL FRACTURES
Dr. Gokul Dev C
JR 1, Dept. Of Orthopaedics
KMCT Medical College

2. General Info
• Sacral fractures are common pelvic ring injuries (30-45%)
• Frequently missed
• 25% - Associated with neurologic injury
• A blow from behind, or a fall onto the ‘tail’
• Women > Men
• Young adults - high energy trauma
• Elderly - low energy falls

3. Anatomy
• Central role in the stability of both
the pelvis and the spinal column.
• Formed by fusion of 5 Sacral Vertebrae
• Fuses at 26 years
• Articulates with
 5th Lumbar Vertebra Proximally
 Coccyx Distally
 Ilium Laterally At Sacroiliac Joints
• Contains 4 Foramina which transmit sacral nerves
• BIOMECHANICS - Transmission of load distributed by first
sacral segment through iliac wings to the acetabulum

5. • Lumbo-pelvic stability is contributed by
– The complex of ligaments that invest the sacrum anteriorly
and posteriorly
– The ligaments of the pelvic floor
– The osseous structure of the sacrum and pelvis
– All these also help to prevent injury to the neurovascular
structures .
ANTERIORLY POSTERIORLY

6. Nerves
• L5 nerve root runs on top of sacral ala
• S1- S4 nerve roots (4 pairs) are transmitted through the
sacral foramina
– S1 and S2 nerve roots carry higher rate of injury
• Lower sacral nerve roots (S2-S5)
– Function
• Anal sphincter tone
• Voluntary contracture
• Bulbo-cavernosus reflex
• Peri-anal sensation
– Unilateral preservation of nerves
is adequate for bowel and bladder control

7. Traumatic “Far Out” Syndrome
• Compression and entrapment of the L5 nerve root in the
extra-foraminal area between the hypertrophied L5
transverse process
and the sacral ala.
• Radiculopathy
• Rx: Minimally invasive
decompressive surgery

8. Etiology
• High energy trauma - RTA
• Direct trauma
• Fall from height
• Insufficiency fracture ( Osteoporosis, Drug induced
osteopenia, Pelvic irradiation, Repetitive stress - Trivial
trauma)
• Pathological fracture.
• Isolated sacrum fracture – RARE

9. AO Classification Of Sacral Injuries
• Type A: Lower Sacro-coccygeal Injuries
– 3 subtypes (A1, A2, A3)
• Type B: Posterior Pelvic Injuries
– 3 subtypes (B1, B2, B3)
• Type C: Spino-pelvic Injuries
– 4 subtypes (C0, C1, C2, C3)

11. Denis Classification
• Based on the fracture line orientation and location with
respect to the sacral foramina
• Zone 1: fracture involves the sacral ala lateral to the neural
foramina
• Zone 2: fracture involves the neural foramina, spinal canal
not involved
• Zone 3: fracture is medial to the neural foramen, involving
the spinal canal; these may be transverse or longitudinal
– Sub-classified into 4 types (Type 1,2,3 and 4)

12. Denis Classification
ZONE I ZONE II ZONE III

13. • Zone 3 sub-classified into 4 types:
Roy-Camille, Strange-Vognsen and Lebech Sub-classification
– Type 1: Only kyphotic angulation at the fracture site (no
translation)
– Type 2: Kyphotic angulation with anterior translation of the
distal sacrum
– Type 3: Kyphotic angulation with complete offset of the
fracture fragments (cephalad and caudal sacrum)
– Type 4: Comminuted S1 segment, usually due to axial
compression

14. • Morphologic injury patterns of zone 3 fractures
– “H” shaped fracture
– “U” shaped fracture
– “ʎ” (lambda) or “Y” shaped fracture
– “ II” shaped fracture
– “T” shaped fracture

15. • Zone 1 fractures
– Fracture lateral to foramina
– Most common (50%)
– Nerve injury rare (5%) - usually
occurs to L5 nerve root
– Mostly - not affect pelvic stability

16. • Zone 2 fractures
– Fracture through foramina
– One third of all sacral fractures
– May be Stable or Unstable
– Zone 2 fracture with shear
component is highly unstable
– Unstable - higher risk of non-
union, poor functional outcome
– Neurologic deficit in 30%

17. • Zone 3 fractures
– Fracture medial to foramina into the spinal canal
– Highest rate of neurologic deficit (60%) -bowel, bladder,
and sexual dysfunction
– fracture lines are all medial to the sacral foramina and
enter the spinal canal,
but can run in a vertical,
oblique/ horizontal direction
– The least common 16%.
– Cauda equina syndrome

18. JUMPER’S FRACTURE : Transverse sacral fractures -
high energy, fall from height
onto lower extremities.
ZONE III FRACTURES

19. Isler classification
• Used for fractures that involve the lumbosacral articulation:
– Isler 1: fracture occurs lateral to the L5/S1 facet
– Isler 2: fractures line involves the L5/S1 facet
– Isler 3: fracture line extends medially to the L5/S1 facet

20. Presentation
• Peripelvic pain
• Slow antalgic gait
• Bruising and/or tenderness is elicited when the sacrum is
palpated from behind or per rectum.
• Test pelvic ring stability by internally and externally rotating
iliac wings
• Can have subcutaneous fluid mass indicative of lumbosacral
fascial degloving
(Morel-Lavallee lesion)
• Trendelenburg test (-)
• SLRT - normal
• FABER Test (+)

21. • Do Perform
– Primary assessment (ABCDE) First – ATLS Protocol
– Neurologic Examination - Saddle Anasthesia
– Genito-urinary and Gastrointestinal examination
• Vaginal Examination - to rule out open injury
• Rectal - Light touch and pinprick sensation
along S2-S5 dermatomes
- Perianal Wink
- Bulbo-cavernosus /Cremasteric Reflexes
– Vascular - Distal Pulses/ Ankle-brachial Index or
Angiogram

22. Imaging
X- RAY - Only show 30% of sacral fractures
- Effective screening tool for sacral fractures
- Often of poor quality
Recommended views
1.AP
2.Lateral - identifies the sacral ala slope (minimizes risk to
the L5 nerve root)

23. 3. Inlet view
- Determining anterior or posterior displacement of SI
joint/sacrum/iliac wing.
- Best assessment of sacral spinal canal and superior
view of S1
4. Outlet view
- Provides true AP of sacrum (optimal visualization of
the S1 neural foramina).
- Determination of vertical displacement of the
hemipelvis
- Subtle signs of pelvic disruption - slightly widened SI
joint, discontinuity of the sacral borders, nondisplaced
sacral fractures, or disruption of the sacral foramina.

24. AP VIEW
LATERAL VIEW
OUTLET VIEW
INLET VIEW

25. Findings in Xrays
• Sacral fractures
• L4 or L5 transverse process fractures
• Asymmetric foramina
• Anterior pelvic ring disruptions
• Stepladder sign - seen on AP view
- Results from displacement with overriding of
transverse fracture fragments
- Indicates disruption of anterior sacral foramina and
lumbro-sacral facets
CT - Diagnostic study of choice (coronal and sagittal
reconstruction views)

26. • MRI
– When neural compromise is suspected
– Limited clinical utility owing to restricted access to a
critically injured patient
– Provide superior imaging of genitourinary and pelvic
vascular structures.
CT VIEWS MRI VIEWS

27. Treatment
• NONOPERATIVE - Progressive weight-bearing +/-
orthosis (Hip Spica casts, bracing, traction techniques)
• Indications
– Stable /minimally displaced
– <1 cm displacement
– No neurologic deficit
– Absence of soft tissue involvement
– Insufficiency fractures
• Weight bearing as tolerated for incomplete fractures
• Touch-toe weight bearing for complete fractures.

28. • Examples:
– Unilateral zones I and II fractures
– Anterior impaction fractures from lateral compression
mechanism
– Isolated sacral ala fractures.
• Most of the cases can be managed conservatively -
takes 8–12 weeks to heal.

29. Sacroplasty
• Non-surgical therapy used to ease pain from a
fractured sacrum due to osteoporosis (insufficiency
fractures) / pathological fractures
• Minimally invasive
• Injecting polymethylmethacrylate (PMMA) cement

30. • OPERATIVE
Surgical fixation
– Indications
• Displaced fractures >1 cm
• Soft tissue compromise
• Persistent pain after non-operative management
• Displacement of fracture after non-operative
management
– Surgical fixation with decompression
• Any evidence of neurologic injury

31. Surgical Fixation
1. Percutaneous Screw Fixation
2. Posterior Tension Band Plating
3. Lumbopelvic Fixation
4. Transiliac Sacral Bars/Rods
5. Decompression Of Neural Elements
6. Triangular Osteosynthesis

32. Percutaneous Screw Fixation
• Screws may be placed as sacroiliac, trans-sacral or trans-
iliac
• Useful for sagittal plane fractures
• Technique
– Screws placed percutaneously under fluoroscopy
– Mostly at the level of S1-S2 segments
– Beware of L5 nerve root
– Avoid overcompression of fracture
– Screw placement posterior to the ICD ensures safe
screw placement (in non-dysmorphic sacrum)
– May result in loss of fixation or malreduction
– Does not allow for removal of loose bone fragments
– Do not use in osteoporotic bone

33. • Risk of anterior screw penetration causing neurologic injury
is much higher with anterosuperior sacral concavity.
• In low-energy fractures, sacral ala fracture - iliosacral screw
fixation, feasible in both the S1 and S2 corridor
ILIO-SACRAL
TRANS-SACRAL

34. Posterior Tension Band Plating
• Posterior two-incision approach
• Technique - May use in addition to ilio-sacral screws
• Allows direct visualization of fracture
• Wound healing complications high
ILIO-ILIAC PLATE

35. • Transverse sacral fractures
– If with severe kyphosis : manipulation and stabilization
done to prevent skin compromise and allow
decompression
– Sacral roots tented over extreme kyphosis
– Simple sacral laminectomy not effective
– Vigorous manipulation can cause rectal perforation
– Reduction is done with Cobb Elevator and Weber clamps
and maintained with plates.

36. Lumbo-Pelvic Fixation
• Posterior approach to lower lumbar spine and sacrum –
mainly for ‘U’ type sacral fracture
• Technique
– Pedicle screw fixation in lumbar spine
– Iliac screws parallel to the inclination angle of outer table
of Ilium
– Longitudinal and transverse rods
• Pros - Shown greatest stiffness when used for
an unstable fracture
- biomechanically robust
• Cons - Invasive
ILIO – LUMBAR FIXATION

37. Transiliac Sacral Bars/Rods
• Alternative to sacro-iliac screws

38. Decompression Of Neural Elements
• The relief of tension/compression of neural structures
entrapped or under traction
• Technique
– Indirect - Reduction (open or closed) through axial
traction - restoring the patency of the neural foramina
– Direct - Posterior approach followed by laminectomy or
foraminotomy
foraminotomy

39. Triangular osteosynthesis
– Subcategory of Spino-pelvic fixation
– This technique offers mechanically better fixation for highly unstable,
vertical shear sacral alar fractures
– The use of a vertical fixation component represented by a lumbo-
pelvic construct (usually unilateral) using transiliac screws
– And a horizontal part represented by a sacroiliac screw/ sacral plate at
the height of the S1 vertebral body or S1 Pedicle Screw and S2 Alar
Iliac Screw
– Provide enhanced multi-planar stability of the LSCFU (the lumbo-
sacro-coccygeal functional unit).
– Smaller displacement & better stability than sacroiliac fixation alone
– Early mobilization of the patient may be achieved, with avoidance of
late deformity
– Can cause destruction of the L5-S1 joint, Need for additional removal
surgery, An increased risk of infection due to the large incision

40. TRIANGULAR OSTEOSYNTHESIS

41. Complications
• Venous thromboembolism- result of immobility
• Iatrogenic nerve injury-
– Overcompression of fracture
– Improper hardware placement
– lower extremity deficits
– Urinary , rectal, sexual dysfunction
• Chronic low back pain.
• Malreduction/Malunion.
– More common with vertically displaced fracture

42. Prognosis
• Fusion rates following sacral fractures after conservative
management have been reported to be 85–90%
• Presence of a neurologic deficit is the most important
factor in predicting outcome
• Displacement confers an increased risk of neurologic
dysfunction
• Mistreated fractures may result in complications

43. References
1. Rockwood and Green’s fractures in adults Ninenth edition
2. Handbook of Fractures 6th Edition 2019 By Kenneth Egol,
Kenneth J. Koval & Joseph Zuckerman
3. Orthobullets : https://www.orthobullets.com/trauma/
1032/sacral-fractures