What is the appropriate management for an adult with uncomplicated acute or sub‑acute low back pain without red‑flag features?

Treatment of Uncomplicated Acute Low Back Pain

First-Line Management: Stay Active Plus Oral NSAIDs

For adults with acute or sub-acute low back pain without red flags, recommend staying active within pain tolerance combined with oral NSAIDs (ibuprofen 400-800mg three times daily, naproxen 500mg twice daily, or diclofenac 50mg twice daily) or acetaminophen if NSAIDs are contraindicated; avoid bed rest entirely. 1

Activity Modification

• Patients should remain active and continue ordinary activities within the limits permitted by pain, as this approach yields small improvements in pain and function compared with bed rest. 1
• Complete bed rest should be avoided, as it is associated with worse disability outcomes. 1, 2
• Patients can return to work early, which reduces long-term disability. 2
• Reassure patients that 90% of episodes resolve within 6 weeks regardless of treatment, though minor flare-ups may occur in the subsequent year. 2

Pharmacologic Options

• Oral NSAIDs provide moderate short-term efficacy for pain relief with good evidence supporting their use as first-line therapy. 1
• Acetaminophen is an appropriate alternative when NSAIDs are not tolerated due to gastrointestinal, cardiovascular, or renal concerns. 1, 3
• Monitor all NSAID use for adverse effects, especially with prolonged courses. 1
• Skeletal muscle relaxants can be added for short-term pain relief when NSAIDs/acetaminophen are insufficient, though evidence is of low quality. 1

Medications to Avoid

• Systemic corticosteroids are not recommended for acute low back pain, as trials show no superiority over placebo. 1, 3
• Opioids should be avoided for long-term management of uncomplicated acute low back pain. 3
• Gabapentin and other antiepileptic agents have insufficient evidence for radicular low back pain. 1
• COX-2 inhibitors have not been shown to be more effective than standard NSAIDs. 2

Non-Pharmacologic Interventions

Spinal Manipulation

• Spinal manipulation performed by a trained practitioner is the only non-pharmacologic intervention with proven short-term benefit for acute low back pain of less than 4 weeks, providing small-to-moderate improvements in pain and function. 1
• However, spinal manipulation is no more effective than established medical treatments when added to them. 4

Exercise Therapy

• Supervised or home exercise programs have not demonstrated effectiveness for acute low back pain in the initial phase and are therefore not recommended. 1
• Consider McKenzie exercises specifically for pain radiating below the knee. 2
• Timing of exercise initiation remains uncertain; some guidelines suggest beginning structured exercise 2-6 weeks after symptom onset. 1

Ineffective Modalities

• Acupuncture, massage, yoga, and cognitive-behavioral therapy lack proven benefit for acute low back pain and are reserved for chronic or sub-acute presentations. 1
• Heat, traction, ultrasound, and transcutaneous electrical nerve stimulation have not shown substantial benefit. 4

Imaging: Avoid Routine Studies

Routine imaging (plain radiographs, CT, MRI) should not be ordered during the initial evaluation of uncomplicated acute low back pain, as it provides no clinical benefit and increases unnecessary healthcare utilization. 1, 3

Harms of Early Imaging

• Early imaging performed within the first 6 weeks is associated with higher likelihood of unnecessary injections, surgical interventions, and disability compensation claims without improvement in patient outcomes. 1
• Ordering imaging solely for reassurance can lead to detection of incidental findings in asymptomatic individuals, triggering unnecessary interventions and worsening outcomes. 1

When to Consider Imaging

• Consider imaging only after 4-6 weeks of optimal conservative management if the patient shows inadequate response and is being evaluated for possible surgical or interventional treatment. 1, 3
• The majority of disc herniations undergo spontaneous reabsorption by approximately 8 weeks after symptom onset, rendering early imaging largely unhelpful. 1

Red-Flag Screening: When to Image Immediately

Critical Red Flags Requiring Emergent Imaging

• Cauda equina syndrome (urinary retention/incontinence, saddle anesthesia, bilateral lower-extremity weakness) mandates emergent MRI and urgent surgical referral. 1, 5
• Progressive motor deficits such as new foot drop require prompt imaging to prevent permanent neurologic injury. 1
• History of cancer with metastatic potential to bone warrants immediate evaluation. 5, 4
• Suspected spinal infection (fever, recent bacterial infection, IV drug use, immunosuppression) requires urgent workup. 5, 4
• Significant trauma in the context of osteoporosis or major mechanism of injury. 5, 4

Predictive Value Caveat

• Only about one-third (≈32%) of commonly cited red-flag symptoms actually correspond to early, treatable cauda equina syndrome; the remaining two-thirds are more likely associated with late, irreversible damage. 1

Psychosocial Risk Factor Assessment

• Screen for depression, anxiety, catastrophizing about pain, fear-avoidance behaviors, passive coping strategies, and job dissatisfaction, as these strongly predict chronic disability and poor outcomes. 5, 3
• Addressing these factors early may prevent progression to chronic low back pain. 3

Follow-Up and Reassessment

• Reassess pain and functional status within 2-4 weeks of initiating therapy; if response is inadequate, consider alternative or adjunctive treatments. 1
• Reevaluate patients with persistent, unimproved symptoms after 1 month for missed red flags or need for physical therapy referral. 3
• Extended courses of oral analgesics should be limited to patients who demonstrate clear ongoing benefit without major adverse events. 1