The first and most important clinical distinction is whether low back pain is 'specific' or 'non-specific.' Specific back pain has an identifiable structural cause requiring targeted treatment — infection, malignancy, fracture, cauda equina syndrome, ankylosing spondylitis, radiculopathy with neurological deficits. This accounts for roughly 5–10% of back pain. Non-specific back pain — the remaining 90% — has no clear identifiable structural cause despite often-dramatic imaging findings.
MRI findings are unreliable guides to back pain treatment. Herniated discs, bulging discs, foraminal stenosis, and degenerative changes are extraordinarily common in pain-free adults. Studies show that 50% of asymptomatic adults over 40 have disc abnormalities on MRI. The finding of a disc herniation on MRI in a person with back pain tells you that this person has a disc herniation — it does not tell you that the disc herniation is causing the pain.
For non-specific low back pain, guidelines consistently recommend: staying active (bed rest is harmful), NSAIDs for short-term analgesia, heat application, physical therapy focused on core stabilization and movement, and addressing psychosocial factors (catastrophizing, fear-avoidance beliefs, depression significantly worsen outcomes). Opioids are not recommended for acute non-specific back pain and are associated with worse long-term outcomes when prescribed early.
Red flag symptoms require urgent evaluation: saddle anesthesia, bowel/bladder dysfunction, progressive neurological deficits (cauda equina syndrome — surgical emergency), fever with back pain (spinal infection), history of cancer with new back pain, severe unrelenting pain worse at rest, or significant trauma. These presentations are uncommon but cannot be missed.