What is the next step in managing a subacute or chronic stress fracture of L5 (lumbar vertebra 5) diagnosed on radiographs?

Management of Subacute or Chronic L5 Stress Fracture on Radiographs

For a subacute or chronic stress fracture of L5 already visible on radiographs, the next step is clinical follow-up without additional imaging in most cases, but MRI without IV contrast should be obtained if you need to determine the full extent of injury for surgical planning, assess for complications like osteonecrosis or delayed healing, or if the patient has persistent/worsening pain despite conservative management. 1, 2

When Additional Imaging is NOT Needed

• After a stress fracture diagnosis is confirmed on radiographs, additional imaging is typically unnecessary. 1
• Most patients should be followed clinically until they are pain-free, at which point they can gradually increase activity in a controlled manner. 1
• The standard approach is conservative management with activity modification and clinical monitoring. 2

When MRI Without IV Contrast IS Indicated

Obtain MRI without IV contrast in the following specific scenarios:

• Need to determine the full extent of injury for surgical planning if conservative management is likely to fail or has already failed. 1, 2
• Persistent or worsening pain despite appropriate conservative management, which suggests complications or progression. 2
• Concern for complications such as osteonecrosis or delayed healing, which would fundamentally alter your treatment approach. 1, 2
• Patient is on bisphosphonate therapy or has osteoporosis, as these patients are especially prone to progression from incomplete to complete fractures. 1, 2
• Need prognostic information for return-to-activity planning, as MRI provides data on marrow edema patterns, cortical signal abnormalities, and fracture line characteristics that predict healing time. 1, 2

Role of CT Without IV Contrast

CT without IV contrast is a reasonable alternative if:

• MRI is contraindicated or unavailable. 2
• You need to identify possible etiologies in delayed healing, such as osteoid osteoma or suspected completion of fracture. 1, 2
• Other imaging modalities are equivocal. 1, 2

CT is less sensitive than MRI but has high specificity (88-98%) for confirming stress fractures. 1

What NOT to Order

• Do not order MRI with IV contrast - it provides no added information over noncontrast imaging for stress injury evaluation. 1, 2
• Do not order CT with IV contrast - it provides no benefit over noncontrast imaging. 1, 2
• Do not repeat radiographs in 10-14 days once the fracture is already confirmed, as this will not provide prognostic information. 1

Critical Pitfalls to Avoid

• Do not assume all stress fractures can be managed identically - vertebral location and patient-specific factors (osteoporosis, bisphosphonate use) significantly impact management. 2
• Do not delay advanced imaging if symptoms persist or worsen - this may indicate progression to complete fracture or complications requiring surgical intervention. 2
• Do not overlook the possibility of pedicle stress fractures in adjacent vertebrae in patients with osteoporotic compression fractures, as this is an additional source of symptoms. 3

Re-evaluation Triggers

Obtain follow-up imaging and re-evaluate original studies if:

• The patient has an unexpected incomplete response to conservative therapy after increasing activity/weight bearing. 1
• Pretreatment symptoms return, suggesting the true etiology of pain was obscured or misdiagnosed. 1