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Introduction
  • Mechanism typically high energy blunt trauma
  • Mortality rate 15-25% for closed fractures, as much as 50% for open fractures
    • hemorrhage is leading cause of death overall  
      • closed head injury is the most common for lateral compression injuries 
    • increased mortality associated with
      • systolic BP <90 on presentation
      • age >60 years
      • increased Injury Severity Score (ISS) or Revised Trauma Score (RTS)
      • need for transfusion > 4 units  
      • higher Young-Burgress classification grade 
  • Associated injuries
    • chest injury in up to 63%
    • long bone fractures in 50%
    • sexual dysfunction up to 50% 
    • head and abdominal injury in 40%
    • spine fractures in 25%
  • Prognosis
    • high prevalence of poor functional outcome and chronic pain
    • poor outcome associated with
      • SI joint incongruity of > 1 cm
      • high degree initial displacement
      • malunion or residual displacement
      • leg length discrepancy > 2 cm
      • nonunion
      • neurologic injury
      • urethral injury
  • Pediatric pelvic ring fractures
    • children with open triradiate cartilage have different fracture patterns than do children whose triradiate cartilage has closed
      • if triradiate cartilage is open the iliac wing is weaker than the elastic pelvic ligaments, resulting in bone failure before pelvic ring disruption
      • for this reason fractures usually involve the pubic rami and iliac wings and rarely require surgical treatment 
Anatomy
  • Osteology
    • ring structure made up of the sacrum and two innominate bones
    • stability dependent on strong surrounding ligamentous structures
    • displacement can only occur with disruption of the ring in two places
    • neurovascular structures intimately associated with posterior pelvic ligaments 
      • high index of suspicion for injury of internal iliac vessels or lumbosacral plexus 
  • Ligaments  
    • anterior 
      • symphyseal ligaments 
        • resist external rotation
    • pelvic floor 
      • sacrospinous ligaments
        • resist external rotation
      • sacrotuberous ligaments
        •  resist shear and flexion
    • posterior sacroiliac complex (posterior tension band)
      • strongest ligaments in the body
      • more important than anterior structures for pelvic ring stability 
      • anterior sacroiliac ligaments
        • resist external rotation after failure of pelvic floor and anterior structures
      • interosseous sacroiliac 
        • resist anterior-posterior translation of pelvis
      • posterior sacroiliac 
        • resist cephalad-caudad displacement of pelvis
      • iliolumbar
        • resist rotation and augment posterior SI ligaments
Physical Exam
  • Symptoms
    • pain & inability to bear weight
  • Physical exam
    • inspection
      • test stability by placing gentle rotational force on each iliac crest
        • low sensitivity for detecting instability 
        • perform only once 
      • look for abnormal lower extremity positioning
        • external rotation of one or both extremities  
        • limb-length discrepancy
    • skin
      • scrotal, labial or perineal hematoma, swelling or ecchymosis
      • flank hematoma
      • lacerations of perineum
      • degloving injuries (Morel-Lavallee lesion) 
    • neurologic exam 
      • rule out lumbosacral plexus injuries (L5 and S1 are most common)
      • rectal exam to evaluate sphincter tone and perirectal sensation
    • urogenital exam
      • most common finding is gross hematuria
      • more common in males (21% in males, 8% in females)
    • vaginal and rectal examinations
      • mandatory to rule out occult open fracture
Imaging
  • Radiographs
    • AP Pelvis 
      • part of initial ATLS evaluation
      • look for asymmetry, rotation or displacement of each hemipelvis
      • evidence of anterior ring injury needs further imaging   
    • inlet view  
      • X-ray beam angled ~45 degrees caudad (may be as little as 25 degrees) 
        • adequate image when S1 overlaps S2 body
      • ideal for visualizing: 
        • anterior or posterior translation of the hemipelvis
        • internal or external rotation of the hemipelvis
        • widening of the SI joint
        • sacral ala impaction
    • outlet view  
      • X-ray beam angled ~45 degrees cephalad (may be as much as 60 degrees)
        • adequate image when pubic symphysis overlies S2 body
      • ideal for visualizing:
        • vertical translation of the hemipelvis
        • flexion/extension of the hemipelvis
        • disruption of sacral foramina and location of sacral fractures
    • radiographic signs of instability 
      • > 5 mm displacement of posterior sacroiliac complex
      • presence of posterior sacral fracture gap
      • avulsion fractures (ischial spine, ischial tuberosity, sacrum, transverse process of 5th lumbar vertebrae)
  • CT 
    • routine part of pelvic ring injury evaluation 
    • better characterization of posterior ring injuries
    • helps define comminution and fragment rotation
    • visualize position of fracture lines relative to sacral foramina
Classification & Treatment
  • Tile classification 
    • A: stable
      • A1: fracture not involving the ring (avulsion or iliac wing fracture)
      • A2: stable or minimally displaced fracture of the ring
      • A3: transverse sacral fracture (Denis zone III sacral fracture)
    • B - rotationally unstable, vertically stable
      • B1: open book injury (external rotation)
      • B2: lateral compression injury (internal rotation)
        • B2-1: with anterior ring rotation/displacement through ipsilateral rami
        • B2-2-with anterior ring rotation/displacement through contralateral rami (bucket-handle injury)
      • B3: bilateral
    • C - rotationally and vertically unstable
      • C1: unilateral
        • C1-1: iliac fracture
        • C1-2: sacroiliac fracture-dislocation
        • C1-3: sacral fracture
      • C2: bilateral with one side type B and one side type C
      • C3: bilateral with both sides type C

  • Young-Burgess Classification   
 
Descriptions
Treatment
Xray
CT
Anterior Posterior Compression (APC)
APC I Symphysis widening < 2.5 cm Non-operative. Protected weight bearing
 
APC II Symphysis widening > 2.5 cm. Anterior SI joint diastasis  . Posterior SI ligaments intact. Disruption of sacrospinous and sacrotuberous ligaments.  Anterior symphyseal plate or external fixator +/- posterior fixation


APC III Disruption of anterior and posterior SI ligaments (SI dislocation). Disruption of sacrospinous and sacrotuberous ligaments.
APCIII
 associated with vascular injury q q
Anterior symphyseal multi-hole plate or external fixator and posterior stabilization with SI screws or plate/screws
Lateral Compression (LC)
LC Type I Oblique or transverse ramus fracture and ipsilateral anterior sacral ala compression fracture. 

Non-operative. Protected weight bearing (complete, comminuted sacral component. Weight bearing as tolerated (simple, incomplete sacral fracture). 
LC Type II Rami fracture and ipsilateral posterior ilium fracture dislocation (crescent fracture).  Open reduction and internal fixation of ilium
 
LC Type III Ipsilateral lateral compression and contralateral APC (windswept pelvis). 
Common mechanism is rollover vehicle accident or pedestrian vs auto. 
Posterior stabilization with plate or SI screws as needed. Percutaneous or open based on injury pattern and surgeon preference. 
 
Vertical Shear (VS)
Vertical shear Posterior and superior directed force. 
Associated with the highest risk of hypovolemic shock (63%); mortality rate up to 25%
Posterior stabilization with plate or SI screws as needed. Percutaneous or open based on injury pattern and surgeon preference.
 
 


Bleeding & Initial Treatment
  • Bleeding Source
    • intraabdominal 
    • intrathoracic 
    • retroperitoneal
    • extremity (thigh compartments)
    • pelvic
      • common sources of hemorrhage
        • venous injury (80%)
          • shearing injury of posterior thin walled venous plexus
        • bleeding cancellous bone
      • uncommon sources of hemorrhage
        • arterial injury (10-20%) 
          • superior gluteal most common (posterior ring injury, APC pattern)
          • internal pudendal (anterior ring injury, LC pattern)
          • obturator (LC pattern)
  • Treatment
    • resuscitation
      • PRBC:FFP:Platelets ideally should be transfused 1:1:1
      • this ratio shown to improve mortality in patients requiring massive transfusion
    • pelvic binder/sheet   
      • indications
        • initial management of an unstable ring injury  
      • contraindications
        • hypothetical risk of over-rotation of hemipelvis and hollow viscus injury (bladder) in pelvic fractures with internal rotation component (LC)
        • no clinical evidence exists of this complication occurring
      • technique 
        • centered over greater trochanters to effect indirect reduction
        • do not place over iliac crest/abdomen
          • ineffective and precludes assessment of abdomen
        • may augment with internal rotation of lower extremities and taping at ankles
        • transition to alternative fixation as soon as possible 
          • prolonged pressure from binder or sheet may cause skin necrosis
        • working portals may be cut in sheet to place percutaneous fixation
      • pitfalls
        • binder can mask pelvic ring injuries, creating false negative radiographs and CT images 
          • stress examination under anesthesia may be indicated in patients who present to the trauma slot in a pelvic binder, hemodynamic instability, and negative pelvis radiographs/CT scan
    • external fixation
      • indications
        • pelvic ring injuries with an external rotation component (APC, VS, CM)
        • unstable ring injury with ongoing blood loss
      • contraindications
        • ilium fracture that precludes safe application
        • acetabular fracture
      • technique 
        • theoretically works by decreasing pelvic volume 
        • stability of bleeding bone surfaces and venous plexus in order to form clot
        • pins inserted into ilium 
          • supra-acetabular pin insertion
          • single pin in column of supracetabular bone from AIIS towards PSIS
            • obturator outlet view 
              • helps to identify pin entry point
            • iliac oblique view 
              • helps to direct pin above greater sciatic notch
            • obturator oblique inlet view 
              • helps to ensure pin placement within inner and outer table
            • AIIS pins can place the lateral femoral cutaneous nerve at risk  
            • pedicle screws with internal subcutaneous bar may be used
          • superior iliac crest pin insertion
          • multiple half pins in the superior iliac crest
            • place in thickest portion of ilium (gluteal pillar)
            • may be placed with minimal fluoroscopy 
        • should be placed before emergent laparotomy 
    • angiography / embolization
      • indications
        • controversial and based on multiple variables including:
        •  protocol of institution, stability of patient, proximity of angiography suite , availability and experience of IR staff
        • CT angiography useful for determining presence or absence of ongoing arterial hemorrhage (98-100% negative predictive value)
      • contraindications
        • not clearly defined
      • technique
        • selective embolization of identifiable bleeding sources
        • in patients with uncontrolled bleeding after selective embolization, bilateral temporary internal iliac embolization may be effective
        • complications include gluteal necrosis and impotence
Definitive Treatment 
  • Nonoperative
    • weight bearing as tolerated
      • indications
        •  mechanically stable pelvic ring injuries including
          • LC1 
            • anterior impaction fracture of sacrum and oblique ramus fractures with < 1cm of posterior ring displacement 
          • APC1
            • widening of symphysis < 2.5 cm with intact posterior pelvic ring q
          • isolated pubic ramus fractures
          • parturition-induced pelvic diastasis
            • bedrest and pelvic binder in acute setting with diastasis less than 4cm
  • Operative
    • ORIF
      • indications
        • symphysis diastasis > 2.5 cm 
        • SI joint displacement > 1 cm
        • sacral fracture with displacement > 1 cm
        • displacement or rotation of hemipelvis
        • open fracture
        • chronic pain and diastasis in parturition-induced  diastasis or acute setting >6cm
      • technique
        • for open fractures aggressive debridement according to open fracture principles
    • anterior subcutaneous pelvic fixator (INFIX)
      • indications
        • same indications as anterior external fixation and symphyseal plating
    • diverting colostomy
      • indications
        • consider in open pelvic fractures
          • especially with extensive perineal injury or rectal involvement
Techniques
  • Anterior ring stabilization
    • single superior plate
      • apply through rectus-splitting Pfannenstiel approach
      • may perform in conjunction with laparotomy or GU procedure
  • Posterior ring stabilization
    • anterior SI plating 
      • risk of L4 and L5 injury with placement of anterior sacral retractors  
    • iliosacral screws (percutaneous)
      • good for sacral fractures and SI dislocations
      • safe zone is in S1 vertebral body
        • outlet radiograph view best guides superior-inferior screw placement  
        • inlet radiograph view best guides anterior-posterior screw placement
      • L5 nerve root injury complication with errors in screw placement   
      • entry point best viewed on lateral sacral view and pelvic outlet views  
      • risk of loss of reduction highest in vertical sacral fracture patterns  
    • posterior SI "tension" plating
      • can have prominent HW complications
  • Anterior and posterior ring stabilization
    • necessary in vertically unstable injuries 
  • Ipsilateral acetabular and pelvic ring fractures
    • reduction and fixation of the pelvic ring should be performed first 
Complications
  • Neurologic injury
    • L5 nerve root runs over sacral ala joint
    • may be injured if SI screw is placed to anterior 
    • anterior subcutaneous pelvic fixator may give rise to LFCN injury (most common) or femoral nerve injury 
  • DVT and PE
    • DVT in ~ 60%, PE in ~ 27%
    • prophylaxis essential
      • mechanical compression
      • pharmacologic prevention (LMWH or Lovenox)
      • vena caval filters (closed head injury)
  • Chronic instability
    • rare complication; can be seen in nonoperative cases
    • presents with subjective instability and mechanical symptoms
    • diagnosed with alternating single-leg-stance pelvic radiographs 
  • Infection 
    • risk factors include:
      • obesity
      • diabetes
      • delay in treatment
      • open fracture 
Urogenital Injuries
  • Present in 12-20% of patients with pelvic fractures
    • higher incidence in males (21%)
  • Includes
    • posterior urethral tear
      • most common urogenital injury with pelvic ring fracture 
    • bladder rupture
      • may see extravasation around the pubic symphysis 
      • associated with mortality of 22-34%
  • Diagnosis 
    • made with retrograde urethrocystogram
    • indications for retrograde urethrocystogram include
      • blood at meatus
      • high riding or excessively mobile prostate
      • hematuria
  • Treatment
    • suprapubic catheter placement 
      • suprapubic catheter is a relative contraindication to anterior ring plating
    • surgical repair
      • rupture should be repaired at the same time or prior to definitive fixation in order to minimize infection risk
  • Complications
    • long-term complications common (up to 35%) 
      • urethral stricture - most common
      • impotence
      • anterior pelvic ring infection
      • incontinence
      • parturition sequelae (i.e. caesarean section)
 

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