Sacral Fracture



  • They occur in 45% of all pelvic fractures and are rarely isolated
  • They are defined by the orientation of the fracture line
  • Mechanism:
    • Axial compression
    • Direct posterior trauma
    • Massive crush injury
    • Insufficiency fractures in elderly and osteoporotic patients

Fracture Classification
  • Above S4:
    • Neurologic injury common
    • Can see cauda equina syndrome (CES)
  • Below S4:
    • Associated rectal tears
    • Neurologic injury is rare

  • Lateral to sacral foramina:
    • Sciatica
    • L5 root injury
    • Neurologic deficit infrequent
  • Foraminal (zone 2):
    • Bowel/bladder dysfunction
    • L5, S1, S2 root injury
    • Neurologic deficit frequent
  • Canal (zone 3):
    • Bowel/bladder dysfunction
    • Sexual dysfunction
    • L5, S1 root injury
    • Neurologic deficit often present (>50%)


  • Transverse: Fall from height, flexion injuries, direct blow
  • Vertical: Usually high-energy mechanism

Geriatric Considerations
Sacral insufficiency fractures should be considered in elderly patients with severe back pain

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