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Pelvic Fractures

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Introduction

  • The majority of pelvic fractures are the result of high-energy blunt injures
  • Patients require emergent and thorough evaluation
  • As compared to the extremities, the pelvis has greater soft tissue constraints, as well as vital non-musculoskeletal structures
  • Treatment of pelvic fractures requires techniques different from those used in the extremities
  • Anchor
    Pelvicfractures-Anatomy
    Treatment can be surgical or nonsurgical, but emphasize the re-establishment of a stable ring structure that allows appropriate transfer of weight from the torso to the hips and legs

Anatomy

Bony Anatomy

  • Pelvis is composed of 3 bones, 1 sacrum and 2 innominate bones
  • Innominate bone forms from the fusion of the immature
    • Ischium (infero-posterior)
    • Illium (superior)
    • Pubis (infero-anterior)
  • The acutabulm forms at the junction of these 3 bones
  • Important bony prominences and landmarks include
    • The anterior superior illiac spine (ASIS)
    • The anterior inferior illiac spine (AIIS)
    • Iliac crest
    • Iliac fossa
    • Posterior superior illiac spine (PSIS)
    • Ischial spine
    • Ischial tuberosity
    • Inferior and superior pubic rami
    • Pectineal eminence
    • Pubic tubercle
  • Figure to show landmarks via lateral view of inominate bone and anterior view of the pelvis

Ring stability

  • The bony pelvis is stabilized primarily by
    • Symphysis pubis
      • Forms the anterior part of the pelvic ring
      • Composed of a complex of
        • Hyaline cartilage
        • Fibrocartilage
        • Fibrous tissues
    • Sacroilliac (SI) joints
      • Forms the posterior part of the pelvic ring
      • Composed of both hyaline and fibro-cartilage
      • Stabilized via posterior, anterior and interosseous ligaments; the latter are the strongest ligaments in the body
      • Not a true synovial joint, as it does not originate from an anlage of condensed mesanchyme
  • The elements of the pelvis are further stabilized relative to each other through
    • Sacro-spinous ligament (anteroposterior and rotational vectors)
    • Long and short sacro-tuberous ligament (vertical vector)
  • From a superior view with the pubis facing down, the sacrum forms an upside down keystone (or suspension bridge) that does not have inherent stability; with loss of bony or ligamentous constraints, the sacrum tends to displace anteriorly (the bridge will fall)
  • From an anterior view the sacrum forms the keystone of an arch that transfers weight from the spine to the acetabuli

...

Pathogenesis

  • Direct impact to the pelvis with indirect transfer of forces to anterior and posterior ring elements
  • Mechanisms of Injury
    • Lateral compression
    • Antero-posterior compression
    • Vertical shear
    • Combination of the above
  • Impact forces cause rotation-translation of a hemipelvis fragment relative to the sacrum in the axial plane or translation in the coronal plane
  • Settings
    • Most commonly motor vehicle and pedestrian-vehicle crashes
    • Motorcycle crashes, fall from heights and crush injuries are less common

Natural History

  • Mortality 5 - 20% (up to 42% for open fractures)
  • Increasing mortality with increased age
  • > 70 years old has 50% mortality
  • Pedestrian injury has 50% mortality
  • Pregnant cases have 33% fetal loss
  • 20 - 40% of females subsequently need caesarean section

Clinical Presentation

  • Comorbidities
    • The risk of additional injuries approaches 40-50%
    • Significant injuries to the viscera, great vessels (highest in APC-III) and head (highest in LC-II) are common with high energy mechanisms
    • APCs have the highest rate of blood loss and death
      • APC-III has a mortality rate as high as 37%
      • Newer studies, however, have called into question these particular associations with specific fracture patterns
  • Associated injured
    • Arteries
      • Internal pudendal : the most frequent cause of active bleeding
      • Iliolumbar artery
      • Superior gluteal artery
      • Lateral sacral artery
      • Internal iliac artery
    • Neurologic
      • L5, S1 are the most commonly injured spinal nerve roots
      • The degree of displacement of the posterior elements rather than specific location appears to be more important determinant of injury
    • GU
      • Bladder
      • Urethra
      • Vagina
    • GI
      • Rectum
      • Distal colon

Imaging and Diagnostic Studies

  • Patients with significant pelvic ring injuries should receive a full trauma evaluation according to American College of Surgeon's Advanced Trauma Life Support
  • Evaluation includes assessment of Airway, Breathing, Circulation

...

  • With any significant pelvic injury, a CT scan with fine cuts should be obtained
  • Allows for measurement of
    • "Safe zone" in the bodies of S1 or S2, if iliosacral screws are indicated
    • Degree of antero-posterior sacral alar comminution
    • SI gapping with hemipelvis rotation
    • Sacral foraminal involvement on coronal images
  • Special attention should be paid to the posterior elements, as sacral fractures can be missed on plain radiographs

Classification

Anatomic

  • The Letournel system is based purely on the location of the fracture
  • show Figure

Mechanism

  • Penal first introduced a mechanistic classification system in 1961
    • Lateral compression (LC)
    • Anterior-posterior compression (APC)
    • Vertical shear (VS)
  • Young and Burgess (1986)
    • LC fractures were subdivided into 3 types:
      • Type I : pubic rami fractures with impaction of the SI joint
      • Type II
        • Pubic rami fractures with internal rotation, posterior disruption
        • Posterior disruption can take 2 forms :
          • Iliac wing fracture
          • Varying degrees of anterior SI impaction and posterior SI disruption depending on location of impact on ilium
      • Type III : LC fracture on one side with APC fracture on the other side
    • APC fractures were divided into 3 types:
      • Type I : Anterior ring widening with intact posterior elements
      • Type II
        • SI anterior widening
        • External rotation of the ilium
        • Disruption of sacro-tuberous and sacro-spinous ligaments
      • Type III : Complete posterior/SI disruption
    • Strength of this system is that it is predictive of associated injuries and may aid in the initial evaluation and stabilization of the patient

...

  • Bucholtz in 1981 and Tile in 1988 created a system based on stability
  • The Tile classification
    • Type A, stable
      • A1 : avulsion
      • A2 : minimally displaced ring
    • Type B, rotationally unstable
    • Type C, rotationally and vertically unstable
  • The OTA/AO scheme presents a variation where
    • Type A is stable
      • A1 : Avulsion
      • A2 : Impaction
      • A3 : Transverse sacral/coccygeal fracture
    • Type B is partially stable
      • B1 : Unilateral/partial in external or internal rotation
      • B2 : Bilateral/partial
    • Type C is unstable
      • C1 : Unilateral/complete
      • C2 : Bilateral/incomplete
      • C3 : Bilateral/complete

Treatment

Resuscitation

  • Fluid replacement
  • Antishock garment
  • Embolisation
  • Direct surgical intervention
  • Application of external fixator can significantly reduce venous and bony bleeding

...

  • B : to aid and maintain reduction
  • C
    • To produce partial stability
    • Decreases bleeding
    • Decreases pain
    • Aids nursing
  • If ORIF is to be performed, it should be delayed, but no more than 7 days, until
    • Patient is stable
    • All investigations completed
    • Operation planned

Complications

  • Anchor
    Pelvicfractures-Outcomes%28oku%26tileboo
    ORIF delayed more than 3 weeks would limit accuracy of reduction, because of callus formation 
  • Non-union / malunion 
    • High incidence in Malgaine type 90%
    • Usually symptomatic
    • High incidence of nerve, bladder complications at revision surgery
  • Infection
    • 6% incidence
    • Increased incidence of infection associated with open bowel injury
    • Increased incidence with ilio-inguinal approach
    • Avoid operations in febrile patients
    • Use prophylactic antibiotics
    • Manage by draining wounds
  • Nerve palsy
    • 11.2% incidence
    • 17.4% in posterior fractures
    • Usually peroneal component of sciatic nerve 
  • Ectopic bone formation 
    • 20% incidence
    • Indomethicin useful
    • Radiation is also an option
  • Thrombo-embolic problems
    • Give anticoagulation for 6 - 8 weeks after open operation
    • 3500 units heparin tds starting at 72 hours post-injury or surgery and adjusted according to APTT (aim for APTT 31-36)
    • Warfarinise after one week post-injury or operation (INR 2 - 2.5)
  • Urethral injury
    • Occurs in 1/3 of unstable fractures (13% overall)
    • Perform retrograde urethrogram prior to IDC
    • Cystogram
    • IVP may be indicated
  • Bladder rupture is usually extra-peritoneal and may lead to vesico-colic or vesical fistulas
  • Impotence 40%
  • Post-traumatic osteoarthritis in 4 - 15%; depends on quality of reduction