When is lumbar spine radiography recommended for patients with acute low back pain?

Guidelines for Lumbar Spine Radiography in Acute Low Back Pain

Do not routinely obtain lumbar spine radiography for patients with acute, nonspecific low back pain—imaging should be reserved for those with red flags suggesting serious underlying conditions or for patients with persistent symptoms after 4-6 weeks of conservative management. 1

When Imaging is NOT Indicated

Routine imaging is not recommended for uncomplicated acute low back pain (duration <4-6 weeks) without red flags, even when radiculopathy is present. 1

• Acute low back pain is self-limiting in most patients, with substantial improvement typically occurring within the first month. 1
• Routine radiography provides no clinical benefit and does not improve patient outcomes compared to selective imaging. 1
• Early imaging leads to increased healthcare utilization, including unnecessary injections, surgeries, and disability compensation. 1
• Radiographic abnormalities are poorly correlated with symptoms and can lead to additional, potentially unnecessary interventions. 1

Radiation Exposure Concerns

Avoid unnecessary ionizing radiation, particularly in young women—a single 2-view lumbar spine radiograph delivers gonadal radiation equivalent to daily chest x-rays for over one year. 1

When Imaging IS Indicated: Red Flags

Obtain imaging promptly when red flags are present on history and physical examination: 1

Immediate/Urgent Imaging Required (MRI or CT preferred over plain radiography):

• Severe or progressive neurologic deficits (motor weakness, sensory loss, reflex changes) 1, 2
• Cauda equina syndrome (saddle anesthesia, bowel/bladder dysfunction, bilateral leg weakness) 1, 2
• Suspected spinal infection (fever, IV drug use, immunosuppression, recent spinal procedure) 1
• Cancer with impending spinal cord compression (known malignancy, unexplained weight loss, age >50 with new onset pain) 1

Delayed diagnosis and treatment of these conditions are associated with poorer outcomes. 1

Plain Radiography May Be Appropriate Initially:

• Suspected vertebral compression fracture in high-risk patients (history of osteoporosis, chronic steroid use, significant trauma, age >70) 1, 2
• History of cancer without signs of cord compression—plain radiography or ESR measurement (≥20 mm/h has 78% sensitivity, 67% specificity for cancer), with MRI reserved for abnormal results 1

Persistent Symptoms Without Red Flags

For patients with persistent low back pain after 4-6 weeks of conservative management without red flags, plain radiography may be a reasonable initial option. 1, 3, 4

• Reevaluate patients with unimproved symptoms after 1 month of conservative treatment. 1
• Consider earlier or more frequent reevaluation in patients with severe pain, functional deficits, older age, or signs of radiculopathy/spinal stenosis. 1

Radiculopathy or Spinal Stenosis

For persistent radiculopathy or spinal stenosis symptoms (>4-6 weeks), obtain MRI (preferred) or CT only if the patient is a potential candidate for surgery or epidural steroid injection. 1, 2

• Most lumbar disc herniation with radiculopathy improves within 4 weeks with conservative management. 1
• Plain radiography cannot visualize discs or accurately evaluate spinal stenosis. 1
• MRI is preferred over CT because it provides better soft tissue visualization, does not use ionizing radiation, and better visualizes vertebral marrow and the spinal canal. 1, 2

Common Pitfalls to Avoid

• Do not image before 4-6 weeks of conservative management in the absence of red flags—this leads to unnecessary procedures and increased healthcare costs. 1, 2
• Do not use CT as first-line imaging for radiculopathy—MRI provides superior soft tissue contrast for nerve root compression. 2
• Do not perform thermography or electrophysiologic testing for nonspecific low back pain evaluation. 1
• Be aware that MRI/CT findings (such as bulging disc without nerve root impingement) are often nonspecific and poorly correlated with symptoms. 1