Low back pain: evaluation and management

Most low back pain is nonspecific and improves with time. Screen for red flags, avoid routine imaging, start with nondrug care, and stratify psychosocial risk; reserve drugs and procedures for selected patients.

1. Screen for serious pathology first. Many guideline red flags barely change probability; a prior history of cancer is the most informative flag for spinal malignancy (post-test probability about 33%) ¹. Saddle anesthesia or urinary retention demands emergent MRI for cauda equina syndrome ².
2. Do not image routinely. Imaging without features of a serious condition does not improve outcomes and can cause harm ³. Disc degeneration and bulges are common in pain-free adults and rise with age, so correlate findings with the clinical picture ⁴.
3. Acute pain: nondrug care first. The ACP recommends superficial heat (moderate-quality evidence), massage, acupuncture or spinal manipulation; if a drug is wanted, an NSAID or skeletal muscle relaxant ⁵. Acetaminophen did not speed recovery from acute low back pain in a large trial ⁶.
4. Chronic pain: active, multimodal treatment. Initial options include exercise, multidisciplinary rehabilitation, acupuncture and mindfulness-based stress reduction (moderate quality), plus tai chi, yoga, CBT and others ⁵. NSAIDs are first-line drugs; tramadol or duloxetine second-line; opioids only after these fail ⁵.
5. Stratify by psychosocial risk. STarT Back matched low-, medium- and high-risk patients to advice, physiotherapy, or psychologically informed physiotherapy, and improved disability over usual best care at 4 and 12 months ⁷.
6. Recognize inflammatory back pain. ASAS features: improvement with exercise, pain at night, insidious onset, onset before 40, and no improvement with rest; four of five suggests axial spondyloarthritis ⁸.

Saddle anesthesia, new urinary retention or reduced anal tone with leg symptoms means cauda equina syndrome: emergent MRI and urgent decompression, not outpatient follow-up ².

• A history of malignancy is the red flag with the highest post-test probability for spinal cancer in back pain ¹.
• Routine imaging without red flags offers no meaningful benefit and adds cost and harm ³.
• At age 50, most pain-free adults have disc degeneration and a majority have a disc bulge on imaging ⁴.
• ACP acute low back pain: superficial heat has moderate-quality evidence; NSAIDs or muscle relaxants if drugs are needed ⁵.
• ACP chronic low back pain: NSAIDs first-line drug, tramadol or duloxetine second-line, opioids last ⁵.
• High-risk STarT Back patients get psychologically informed physiotherapy, not advice alone ⁷.
• Improvement with exercise is the strongest single feature of inflammatory back pain (odds ratio 23.1) ⁸.

• Treating an MRI disc bulge as the pain generator without matching symptoms ⁴.
• Choosing acetaminophen as the evidence-based first drug for acute low back pain ⁶.
• Assuming every guideline red flag is equally informative; most change probability little ¹.