What is the next step in managing a subacute or chronic stress fracture of the L5 vertebra?

Next Step for Subacute or Chronic L5 Stress Fracture on X-ray

For a confirmed subacute or chronic stress fracture of L5 on radiographs, the next step is MRI without IV contrast to determine the full extent of injury, assess for complications (such as osteonecrosis or delayed healing), and guide treatment planning. 1

Rationale for MRI After Positive Radiographs

Once a stress fracture diagnosis is established on x-ray, additional imaging is typically not needed for most stress fractures, as patients are followed clinically until pain-free 1. However, vertebral stress fractures warrant special consideration because:

• MRI provides prognostic information beyond simple diagnosis, including assessment of marrow edema patterns, cortical signal abnormalities, and fracture line characteristics that predict healing time 1
• MRI identifies complications such as osteonecrosis, delayed healing, or progression to complete fracture that would alter management 1
• MRI evaluates the full extent of involvement which is critical for surgical planning if conservative management fails 1

When MRI is Most Appropriate

Order MRI without IV contrast if:

• You need to determine extent for surgical planning 1
• The patient has persistent or worsening pain despite appropriate conservative management 1
• There is concern for complications like osteonecrosis or delayed healing 1
• The patient is on bisphosphonate therapy or has osteoporosis (higher risk for progression to complete fracture) 1
• You need prognostic information for return-to-activity planning 1

MRI with IV contrast is reserved only for suspected complications like osteonecrosis, osteoid osteoma, or tumor causing persistent symptoms 1

CT Scanning Role

CT without IV contrast can be useful if:

• MRI is contraindicated or unavailable 1
• You need to identify possible etiologies in delayed healing (such as osteoid osteoma or suspected completion of fracture) 1
• Other imaging modalities are equivocal 1

CT with contrast provides no added benefit over noncontrast imaging for stress injury evaluation 1

Clinical Management Considerations

Conservative management remains first-line treatment for most stress fractures, with clinical follow-up until pain-free, then controlled activity increase 1. However, vertebral stress fractures require careful monitoring because:

• Patients with osteoporosis are especially prone to progression from incomplete to complete fractures 1
• Bilateral pedicle stress fractures can occur in the setting of adjacent vertebral compression fractures 2
• Failure of conservative therapy warrants re-evaluation with advanced imaging 1

Common Pitfalls to Avoid

• Do not assume all stress fractures can be managed identically - vertebral location and patient factors (osteoporosis, bisphosphonate use) significantly impact management 1
• Do not delay advanced imaging if symptoms persist or worsen - this may indicate progression or complications requiring surgical intervention 1
• Do not order CT with contrast - it provides no additional information for stress fracture evaluation 1