What is the meaning of butterfly vertebrae?

Butterfly Vertebra: Definition and Clinical Significance

Butterfly vertebra is a congenital vertebral anomaly characterized by a sagittal cleft in the vertebral body, resulting in a butterfly-like appearance on imaging. 1

Anatomical Features and Embryology

• Butterfly vertebra results from a symmetric fusion defect during vertebral formation, creating a sagittal cleft through the vertebral body 2
• The defect appears as anterior wedging on lateral radiographs and a butterfly-like shape on anteroposterior views 3
• This anomaly represents a failure of fusion of the lateral halves of the vertebral body during embryonic development 4

Clinical Significance

• Butterfly vertebrae are typically asymptomatic and discovered incidentally during imaging for unrelated conditions 5
• They can occur at any level of the spine but are most commonly reported in the thoracic and lumbar regions 3
• The condition may be isolated or associated with multiple vertebral levels, though multiple level involvement is rare 2

Associated Conditions

• Butterfly vertebrae can be associated with various syndromes, including:
  • Klippel-Feil syndrome 6
  • Split cord malformation (SCM) 1
  • Pfeiffer syndrome 5
  • Jarcho-Levins syndrome 5
  • Crouzon syndrome 5
  • Alagille syndrome 5

Diagnostic Considerations

• Butterfly vertebrae can be misdiagnosed as vertebral fractures, infections, or metastatic lesions on imaging 3
• Key diagnostic features include:
  • Symmetric sagittal cleft through the vertebral body 2
  • Preserved posterior elements of the vertebra 3
  • No associated bone destruction or soft tissue mass 3
  • Normal adjacent intervertebral discs 4

Imaging Modalities

• Plain radiographs can identify the characteristic appearance but may be confused with fractures 5
• CT scans provide detailed visualization of the bony defect and help differentiate from pathologic conditions 3
• MRI is valuable for evaluating associated spinal cord abnormalities, especially in cases with neurological symptoms 1

Management Approach

• Most butterfly vertebrae require no specific treatment as they are typically asymptomatic 4
• When symptomatic, management focuses on treating associated conditions rather than the vertebral anomaly itself 2
• Further evaluation is necessary when butterfly vertebrae are discovered to exclude:
  • Pathologic fractures 5
  • Infections 3
  • Associated vertebral anomalies 1
  • Related syndromes that may require specific management 5

Clinical Pitfalls to Avoid

• Misdiagnosing butterfly vertebrae as compression fractures, leading to unnecessary interventions 3
• Failing to evaluate for associated congenital anomalies, especially in pediatric patients 1
• Attributing unrelated symptoms to the incidental finding of butterfly vertebrae 4
• Unnecessary invasive procedures or biopsies when the condition is mistaken for a pathologic process 3