Is an MRI indicated for a patient with chronic, progressively worsening neck pain and a possible pars defect at C2-C3 on X-ray?

MRI for Chronic Neck Pain with Possible C2-C3 Pars Defect

MRI is indicated for this 51-year-old female with chronic progressively worsening neck pain and a possible pars defect at C2-C3 on X-ray due to the potential for neural compression and instability.

Rationale for MRI in This Case

• Cervical pars defects are rare conditions that can lead to spinal instability, which may explain the patient's progressively worsening symptoms 1
• When a pars defect is identified on X-ray, especially with progressive symptoms, MRI is appropriate to evaluate for:
  • Potential neural compression (cord or nerve roots)
  • Soft tissue abnormalities not visible on X-ray
  • Bone marrow edema indicating active stress response 2

Evidence Supporting MRI in This Specific Scenario

• While routine MRI is not recommended for chronic neck pain without neurological symptoms, the presence of a structural abnormality (pars defect) on X-ray represents a "red flag" that warrants further evaluation 3
• Progressive worsening of symptoms in conjunction with a structural finding suggests potential instability that requires comprehensive evaluation 1
• MRI is more sensitive than CT in identifying degenerative cervical disorders and soft tissue abnormalities that may be contributing to symptoms 3

Clinical Considerations

• Cervical spondylolysis (pars defect) can cause:
  • Progressive instability at the affected segment
  • Significant neck pain
  • Potential neurological symptoms if there is cord or nerve root compression 1
• The C2-C3 level is a critical junction in the cervical spine, and instability here can lead to significant morbidity 1
• A pars defect must be differentiated from an acute traumatic fracture (such as a hangman's fracture), which MRI can help accomplish 1

Imaging Algorithm for This Patient

1. Initial imaging: X-ray has already been performed, showing a possible pars defect
2. Next appropriate step: MRI without contrast to evaluate:
   • Soft tissue structures including ligaments, discs, and neural elements 3
   • Presence of bone marrow edema indicating active stress response 2
   • Potential spinal cord or nerve root compression 3
3. Consider CT only if:
   • MRI is contraindicated
   • More detailed bony anatomy is needed after MRI 3, 4

Important Caveats

• MRI findings must be interpreted in the context of clinical symptoms, as degenerative changes are common in asymptomatic individuals over age 30 3
• The presence of a pars defect with progressive symptoms represents a situation different from routine chronic neck pain, where imaging might not be indicated initially 3
• While CT provides superior visualization of bony anatomy, MRI is preferred initially due to its ability to evaluate neural elements and detect early stress response without radiation exposure 4, 2
• Flexion-extension radiographs may be considered as a complement to MRI if there is concern for instability 3