Low back pain

• Pain and/or stiffness localized to the lower back (below the costal margin) and above the buttocks.

• May be accompanied by pain radiating down the legs.

• Poor posture

• Sedentary lifestyle, low physical activity

• Activities involving heavy lifting

• Age

• Psychological stressors (e.g., stress, anxiety, depression)

• Mechanical: trauma (e.g., spinal fracture)

• Anatomical: scoliosis

• Degenerative: disc herniation, spinal stenosis, disc protrusion, spondylolisthesis (see also “Degenerative disc disease”)

• Inflammatory: ankylosing spondylitis, reactive arthritis, inflammatory bowel diseases

• Infectious: abscess (e.g., paraspinal, epidural), osteomyelitis, discitis

• Malignant: metastases, tumors, multiple myeloma

• According to severity

  • Uncomplicated: without red flag features for acute back pain

  • Complicated: with red flag features for acute back pain

  • See “Red flag features for acute back pain.”

• According to duration

  • Acute: up to 4–6 weeks

  • Subacute: 6–12 weeks

  • Chronic: > 12 weeks

Assess for red flag features of acute back pain in all patients.

• Examine sensation, power (motor strength), deep tendon reflexes, and superficial reflexes (e.g., Babinski reflex) below the level of the pain bilaterally.

• Assess for signs of nerve root irritation (e.g., straight leg raise test).

• Assess perianal sensation and anal tone.

Imaging is not routinely required for acute back pain. Indications for imaging include suspicion for a serious underlying etiology (e.g., severe or progressive neurological findings, red flag features of underlying malignancy or spinal infection) or pain that persists despite at least 4 weeks of conservative management.

• Major risk factor: history of cancer

• Clinical features: sudden onset or rapid progression of any of the following

  • Back pain, radicular pain

  • Neurological defects below the level of the lesion

    • Sensory defects

    • Progressive weakness of the legs

    • Altered reflexes (initial hyporeflexia; followed by hyperreflexia and extensor plantar response)

    • Bladder and bowel dysfunction; loss of spincter tone

    • Features of incomplete cord syndromes (e.g., Brown-Séquard syndrome) [16]

• Preferred initial imaging modality: urgent MRI with or without IV contrast

  • Evidence of extrinsic cord compression (e.g., tumor, intervertebral disk herniation, hematoma

  • High signal areas on T2 within the cord, representing acute edema

• Alternative: CT myelography; similar findings to MRI

• Urgent neurosurgery consult for surgical decompression

• Malignant spinal cord compression: high-dose IV steroids [17]

• Treatment of the underlying cause (e.g., radiotherapy for metastases, surgical evacuation of abscesses, spine stabilization surgery)

• Major risk factor: preexisting degenerative disk disease

• Clinical features

  • Severe low back pain

  • Asymmetric, areflexic, flaccid paresis of bilateral legs (cauda equina syndrome)

  • Symmetric, hyperreflexic paresis of lower limbs (conus medullaris syndrome)

  • Saddle anesthesia

  • Urinary retention with overflow incontinence

  • Fecal incontinence; loss of sphincter tone

• Preferred initial imaging modality: urgent MRI lumbar spine without and with IV contrast [13]

  • Evidence of extrinsic cord compression (intervertebral disk herniation, hematoma, tumor)

  • Edema of the cauda equina (high signal intensity on T2)

• Alternative: CT lumbar spine without IV contrast or CT myelography [13]

  • Similar findings to MRI

  • Hourglass-like constriction due to partial or complete block of contrast (on myelography)

• Bladder scan: may show retention

• Urinary catheter if the patient has retention

• Urgent neurosurgery consult for surgical decompression.