Pelvic fractures

2. SI Dislocation & Crescent Fractures

3. • Incomplete (Sacroiliac) SI dislocation
 posterior SI ligaments remain intact
 rotationally unstable
• Complete SI dislocations
 posterior SI ligaments ruptured
 vertically and rotationally unstable
• SI fracture-dislocation (crescent fracture)
 iliac wing fracture that enters the SI joint
 injury to posterior ligaments vary
 combination of vertical iliac fx and SI dislocation
 posterior ilium remains attached to sacrum by posterior SI ligaments
 anterior ilium dislocates from sacrum with internal rotation deformity
 when ilium fragment remains with sacrum it is termed a crescent fracture

4. • Mechanism of injury
 lateral compression force
 usually high energy
• Degree of injury to posterior structures determines pelvic stability
• Iliac wing fractures may be associated with open wounds and may involve bowel
entrapment
• Prognosis
 primarily based on accurate and stable reduction of SI joint

5. • Anatomy
 Ligaments:
the SI joint is stabilized by the posterior pelvic ligaments
 Sacrospinous
 Sacrotuberous
 Anterior sacroiliac
 Posterior sacroiliac
 Nerves
L5 nerve root crosses the sacral ala approximately 2 cm medial to SIJ
 Blood supply
 The superior gluteal artery runs across SI joint
 exits pelvis via greater sciatic notch

6. • Classification:
 No classification system specifically for SI injury
 included in Young- Burgess and Tile classification of pelvic fractures
 crescent fractures described as LC-2 injury according to Young-Burgess
• Presentation
 Symptoms
 pelvic pain
 Physical Exam
 assess hemodynamic status
 perform detailed neurological exam
 abdominal assessment to look for distention
 rectal exam
 examine urethral meatus for blood

7. • Imaging
 Radiographs
 AP pelvis
 Inlet and outlet views
 CT scan
 evaluation of sacral fractures
 posterior pelvis better delineated

8. • Treatment
 Operative
 Immediate skeletal traction
For vertical translation of the hemipelvis
 Anterior ring ORIF
For incomplete SI dislocations with pubic symphyseal diastasis

9. • Anterior and posterior ring ORIF
 Indications
 complete SI dislocations
vertically unstable require anterior and posterior pelvic ring fixation
• ORIF of ilium
 Indications
 crescent fracture
required to restore posterior SI ligaments and pelvic stability

10. • Closed Reduction and Percutaneous Fixation
 Positioning
 Intraoperative traction may aid in reduction
 Small midline bump under sacrum may assist with SI screw placement
 Imaging
 inlet view
shows anterior-posterior position of SI joint(s) for screw placement
 outlet view
shows cephalad-caudad position of SI joint(s) for screw placement
 lateral sacral view
ensures safe placement of SI or sacral screws relative to the anterior cortex of
the sacral ala and the nerve root tunnel
 Complications
 L5 nerve root at risk with anterior perforation of iliosacral screw as nerve goes
inferiorly over sacral ala

11. Reduction
General guideline
• Reduction maneuvers follow the sequence below until satisfactory
reduction is achieved at each site of deformity:
• external manipulation
• percutaneous control and manipulation of displaced pelvic segments
• open reduction

12. Reduction of a pure SI dislocation with
associated symphysis disruption
• ORIF of pubic symphysis disruption, if performed first, will assist with reduction of the SI
joint.
• This can be assisted by manual traction on a supra-acetabular Schanz screw if necessary.
• Any residual SI joint widening can usually be reduced by tightening an iliosacral lag screw.
Be careful to use a washer and monitor screw-head with a tangential x-ray to avoid
driving the screw through the outer table of the ilium, and compromising compressive
fixation.
• Before and after definitive fixation, confirm satisfactory overall alignment of the pelvis
with C-arm fluoroscopy in multiple views, or inlet and outlet views with portable x-ray.

13. Reduction of a pure SI dislocation with associated
pubic ramus fractures
• Reduction of the SI joint usually results in satisfactory alignment of
the ramus fractures. An external fixator can be applied for provisional
fixation, and either left until the ramus fractures heal, or replaced
with a ramus screw, or plate.
• Before and after definitive fixation, confirm satisfactory alignment of
the pelvis with C-arm fluoroscopy in multiple views.

14. Reduction of SI fracture dislocations
• Unstable fracture dislocations of the sacroiliac joint typically involve
an articular fragment of the posterior ilium (crescent fractures). This
posterior iliac fragment is variably sized and remains attached to the
sacrum by the posterior sacroiliac ligament.
• If the majority of the iliac articular surface is intact, reduction may be
performed as for a pure SI dislocation.
• If satisfactory closed reduction of the SI joint cannot be achieved,
anterior or posterior open reduction is performed.

15. • If satisfactory closed reduction of the SI joint cannot be achieved, anterior
or posterior open reduction is performed.
• With a large crescent fragment, iliosacral screw fixation may be impossible
since the fracture line may interfere with the screw entry site. If so, ORIF of
the crescent fracture may be the best option for repairing the SI joint.
Depending on the fracture configuration and the soft tissues, this may be
performed either anteriorly or posteriorly.
• Reduction of the SI joint usually results in satisfactory alignment of the
anterior arch, which typically involves fractured rami.
• Restoration of normal pelvic alignment must be monitored during
reduction and fixation, and not lost sight of during repair of individual
fractures

16. Fixation
• Pure SI joint dislocation
Principles of ISS fixation for SI joint
A partially threaded lag screw is used for joint compression.
A washer is necessary to maximize purchase on the ilium without burying the screw
head in the bone.
Fixation failure may occur, especially with grossly unstable injuries. Fixation can be
enhanced by one or more of the following:
1 or 2 additional screws (S1 or S2 level)
Supplementary plates, posteriorly or anteriorly
Anterior arch fixation increases stability

17. Sacroiliac fracture dislocation
• Fracture dislocations with a small crescent fragment are usually best
addressed with an iliosacral screw, if satisfactory reduced.
• Iliosacral screw for SI joint

18. Posterior ORIF SI fracture
• Indication crescent fracture is a fracture dislocation of the SI joint.

19. Anterior ORIF SI fracture
• Instability of the sacroiliac joint occurs most commonly with a pure
disruption of the sacroiliac joint.
A. Drilling of the sacral screw
• Drill a hole in the lateral part of the sacrum (close to the linea
terminalis) directly parallel to the SI-joint using a 3.2 mm drill bit.
• Alternatively small fragment plates may be considered.

20. b. Plate application
• Apply a 4.5 mm 3-hole DC-plate for dynamic compression.
• The plates are contoured using a table top bending press. The plates
are contoured to fit across the SI joint with one screw in the sacrum
and two in the ilium.
• Precontour the plate in the direction of the pelvic brim (linea
terminalis) and apply the cortical, sacral screw.
• The sacral screw hole is drilled carefully, to avoid injury to the
lumbosacral nerve trunk but not enter the sloping SI joint. This screw
is inserted and tightened in the neutral position.

21. • The medial iliac screw is inserted in compression. Then the lateral
screw is inserted in neutral.

22.  Complications
• DVT (35%-50%)
• Neurological injury
• Loss of reduction and failure of fixation

24. • Under-diagnosed and often mistreated fractures that may result in neurologic
compromise
• common in pelvic ring injuries (30-45%)
• 25% are associated with neurologic injury
• Frequently missed:
 75% in patients who are neurologically intact
 50% in patients who have a neurologic deficit
• Epidemiology
 Young adults: as a result of high energy trauma
 Elderly: as a result of low energy falls

25. • Prognosis
 Presence of a neurologic deficit is the most important factor in predicting
outcome
 Mistreated fractures may result in:
 lower extremity deficits
 urinary dysfunction
 rectal dysfunction
 sexual dysfunction
• Anatomy:
 Formed by fusion of 5 sacral vertebrae
• Articulates with:
 5th lumbar vertebra proximally
 coccyx distally
 ilium laterally at sacroiliac joints
• Contains 4 foramina which transmit sacral nerves

26. • Nerves:
 L5 nerve root runs on top of sacral ala
 S1-S4 nerve roots 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
 bulbocavernosus reflex
 perianal sensation
 unilateral preservation of nerves is adequate for bowel and bladder control
• Biomechanics
 transmission of load distributed by first sacral segment through iliac wings to
the acetabulum

28. • Denis classification
 zone 1
 fracture lateral to foramina
 most common (50%)
 nerve injury rare (5%)
 usually occurs to L5 nerve root
 zone 2
 fracture through foramina
 Stable or unstable
 zone 2 fracture with shear component highly unstable
 increased risk of nonunion and poor functional outcome
 zone 3
 fracture medial to foramina into the spinal canal
 highest rate of neurologic deficit (60%)
 bowel, bladder, and sexual dysfunction

29.  zone 1
 zone 2
 zone 3

30. • Transverse sacral fractures
higher incidence of nerve dysfunction
• U-type sacral fractures
results from axial loading
represent spino-pelvic dissociation
high incidence of neurologic complications

32. • History
 motor vehicle accident or fall from height most common
 repetitive stress
 insufficiency fracture in osteoporotic adults
• Symptoms
 peripelvic pain
• Inspection
 soft tissue trauma around pelvis should raise concerns for pelvic or sacral fracture

33. • Palpation
 test pelvic ring stability by internally and externally rotating iliac wings
 palpate for subcutaneous fluid mass indicative of lumbosacral fascial
degloving(Morel-Lavallee lesion)
 perform vaginal exam in women to rule-out open injury
• neurologic exam
 rectal exam
 light touch and pinprick sensation along S2-S5 dermatomes
 perianal wink
 bulbocavernosus and cremasteric reflexes
• vascular exam
 Distal pulses
 If different consider ankle-brachial index or angiogram

34. • Imaging
 Radiographs
 only show 30% of sacral fractures
 AP pelvis
 inlet view
best assessment of sacral spinal canal and superior view of S1
 outlet view
provides true AP of sacrum
 cross-table lateral
effective screening tool for sacral fractures
often of poor quality
 findings
L4 or L5 transverse process fractures
asymmetric foramina

35. • CT
 diagnostic study of choice
 recommend coronal and sagittal reconstruction views
• MRI
 recommended when neural compromise is suspected

37. • Nonoperative
 progressive weight bearing +/- orthosis
 Indications:
 <1 cm displacement and no neurologic deficit
 insufficiency fractures
• 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
 indications
 any evidence of neurologic injury

38. • Surgical Techniques
 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
 beware of L5 nerve root
 avoid overcompression of fracture
 may cause iatrogenic nerve dysfunction
 Cons:
 may result in loss of fixation or malreduction
 does not allow for removal of loose bone fragments
 do not use in osteoporotic bone

39.  Iliosacral and lumbopelvic fixation
 posterior approach to lower lumbar spine and sacrum
 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 to have greatest stiffness when used for an unstable sacral fracture
 cons
invasive

40. Entry points for sacral screw fixation
Safe placement of screws avoids
the spinal canal and sacral nerve root
channels by using the illustrated lateral
entry points proximal and
distal to the fracture bilaterally.
This is lateral to the sacral foramina
and nerve roots, or between and in line with the sacral foramina.

41.  Decompression of neural elements
 Technique:
 indirect
reduction through axial traction
 direct
posterior approach followed by laminectomy or foraminotomy
Plate fixation
Fixation is performed with two (bilateral) small fragment plates (4-6
holes).

42. • Complications
 Venous thromboembolism
 o often as a result of immobility
 Iatrogenic nerve injury may result from
 overcompression of fracture
 improper hardware placement
 Malreduction
 more common with vertically displaced fractures

44. • Most are unstable fractures
• Typically progress from iliac crest to greater sciatic notch
• Iliac wing fractures have high incidence of associated injuries
 open injuries
 bowel entrapment
 soft tissue degloving

45. • Anatomy
 pelvic girdle is comprised of
 sacrum
 2 innominate (coxal) bones
 each formed from the union of 3 bones: ilium, ischium, and pubis
 ilium
 2 important anterior prominences
 anterior-superior iliac spine (ASIS)
origin of sartorius and transverse and internal abdominal muscles
 anterior-inferior iliac spine (AIIS)
origin of direct head of rectus femoris and iliofemoral ligament (Y
ligament of Bigelow)
 posterior prominences
 posterior-superior iliac spine (PSIS)
located 4-5 cm lateral to the S2 spinous process
 posterior-inferior iliac spine (PIIS)

46. • Imaging
 Plain radiographs
 standard set of AP pelvis, inlet/outlet, and judet views
 helpful for evaluating the iliac wing in addition to pelvic stability and
possible acetabular involvement
 CT scan
 carefully assess CT scan for signs of bowel entrapment
 evaluate for presence of gas or air in the soft tissues which can be associated
with open injury or bowel disruption

47. • Classification
 No specific classification for iliac wing fractures
 Generally described as specific subtypes of more common classification
systems
 Tile Classification
 Stable (intact posterior arch)
 A1-1: iliac spine avulsion injury
 A1-2: iliac crest avulsion
 A2-1: iliac wing fractures often from a direct blow
 Partially stable (incomplete disruption of posterior arch)
 B2-3: incomplete posterior iliac fracture
 Unstable (complete disruption of posterior arch)
 C1-1: unilateral iliac fracture

48. • Treatment
 Nonoperative
 mobilization with an assist device
 indications
 nondisplaced fractures
 isolated iliac wing fractures
 Operative
 open reduction and internal fixation
 Indications
 displaced fractures of ilium

49.  Operative Techniques
 Wound Management
 evaluate all wounds for
 soft tissue disruption or internal degloving injury
 possible soft tissue or bowel entrapment in the fracture site
 prophylactic antibiotics as appropriate
 serial debridements as necessary
 Open Reduction Internal Fixation
 posterior approach
 ilioinguinal approach
 Stoppa approach (lateral window)

50. Reduction
• Reduction is performed under direct vision using either a reduction
forceps or Schanz screws as joysticks.
• In comminuted fractures, anatomic reduction is not necessary. The
basic shape of the iliac wing should be reconstructed.
• Temporary fixation is obtained by insertion of K-wires.

51. Fixation
• A 3.5 mm reconstruction plate is contoured to fit the individual
anatomy of the superior part of the iliac crest (green dotted line).
• The bone stock of the central fossa is too thin to allow for adequate
purchase of screws.

52. Fixation
• The plate is placed and fixed with screws.
• Alternatively, long 3.5 mm screws placed between
the tables of the superior ala can be used. These
trans-iliac screws can be further supplemented
with plate fixation.

53. Aftercare following open reduction and
fixation
• Postoperative blood test
• Bowel function and food
• Analgesics
• Anticoagulation
• Drains
• Wound dressing