Chronic Back Pain — Causes, Assessment, Physiotherapy & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Chronic back pain (CBP) is defined as back pain lasting more than 12 weeks. It is the single leading cause of disability globally, affecting approximately 20% of adults and accounting for more years lived with disability (YLDs) than any other condition. The vast majority (up to 90%) of chronic low back pain (LBP) is classified as non-specific — meaning no definitive structural pathology fully accounts for the pain, and the relationship between imaging findings and symptoms is poor. Chronic pain involves complex neurobiological mechanisms including central sensitisation (hyperexcitability of nociceptive pathways), altered pain processing, and significant psychosocial drivers — the biopsychosocial model is now the accepted framework for understanding and managing CBP. A minority of patients have specific causes: disc herniation with radiculopathy (sciatica), lumbar spinal stenosis, spondylolysis/spondylolisthesis, vertebral fractures, inflammatory arthropathy (ankylosing spondylitis, PsA), or rarely, sinister pathology requiring immediate investigation.

Non-specific chronic low back pain: degenerative disc disease (disc dehydration and height loss — present on MRI in 40% of asymptomatic adults over 30, so imaging findings must be interpreted with caution); facet joint arthropathy; sacroiliac joint dysfunction; myofascial pain; and central sensitisation — where the pain nervous system itself becomes hyperexcitable, amplifying pain signals independent of peripheral tissue damage. Specific structural causes: lumbar disc herniation with nerve root compression (L4/L5 or L5/S1 levels most common — causing sciatica: leg pain below the knee in a dermatomal distribution, numbness, weakness, reduced reflexes); lumbar spinal stenosis (acquired narrowing of the spinal canal — causes neurogenic claudication: bilateral leg pain worse on walking, relieved by sitting forward); spondylolisthesis (forward slip of one vertebra on another); vertebral fractures (osteoporotic compression fractures in postmenopausal women); inflammatory back pain (ankylosing spondylitis/axial spondyloarthropathy — insidious onset under 45, worse with rest, better with exercise, morning stiffness above 30 minutes). Psychosocial risk factors ('yellow flags') for chronification: depression, anxiety, catastrophising, fear-avoidance behaviour, low self-efficacy, job dissatisfaction, and prolonged sick leave — these predict outcome better than imaging findings or pain severity.

Chronic non-specific low back pain: persistent dull, aching, or cramping pain in the lumbar region; stiffness (particularly morning stiffness lasting under 30 minutes — prolonged morning stiffness suggests inflammatory aetiology); pain varying with activity and posture; disturbed sleep; and significant functional limitation. Radiculopathy (nerve root pain): unilateral leg pain that is typically more severe than the back pain; follows a dermatomal distribution below the knee; associated with paraesthesiae (tingling), numbness, and weakness. L4 (knee extension weakness, reduced knee jerk); L5 (big toe and foot dorsiflexion weakness, no reflex change); S1 (ankle plantarflexion weakness, reduced ankle jerk). Neurogenic claudication (stenosis): bilateral leg heaviness, pain, and tingling on walking, relieved by sitting, bending forward, or resting — the 'shopping trolley sign' (leaning on a trolley provides relief by flexing the spine). Red flags (ALARM features) requiring urgent investigation: new onset in age above 50 or under 20; thoracic pain; constant progressive pain; night pain disturbing sleep; bladder or bowel dysfunction (cauda equina syndrome — medical emergency); bilateral leg weakness; unexplained weight loss; fever; history of cancer; or spinal deformity.

Clinical assessment: comprehensive history including onset, character, radiation, aggravating/relieving factors, associated neurological symptoms, psychosocial yellow flags (using validated tools such as the Keele STarT Back Screening Tool — categorises patients into low, medium, and high risk for stratified care), and impact on function. Neurological examination: straight leg raise (SLR — positive at below 60 degrees if sciatica from disc herniation, causing radicular leg pain); slump test; power, reflexes, and sensation in both lower limbs. Imaging: not routinely indicated for non-specific LBP in the absence of red flags — up to 95% of people have 'abnormal' findings on MRI (disc bulges, degeneration) with no correlation to pain. MRI lumbar spine: for suspected cauda equina syndrome (emergency — same day), radiculopathy not responding to 6 weeks of conservative management, inflammatory back pain, cancer history, or vertebral fracture. CT lumbar spine: for pre-surgical planning or when MRI is contraindicated. Blood tests: FBC, ESR, CRP (for inflammatory arthropathy or infection); HLA-B27 (ankylosing spondylitis); PSA, bone profile, protein electrophoresis (cancer workup). DXA scan: for osteoporotic fracture assessment in postmenopausal women.

Active rehabilitation is the cornerstone of chronic back pain management — not rest, which worsens outcome. NICE 2016 (updated 2023) prioritises non-pharmacological therapies. Exercise therapy: structured exercise programmes (physiotherapy-led; Pilates-based exercise; yoga; aerobic exercise) — any form of supervised exercise is effective; the specific type matters less than consistency; 12+ session programmes are more effective than brief courses. Manual therapy: spinal manipulation, mobilisation, and massage — short-term benefit for low back pain, best as part of a multimodal programme rather than standalone. Psychological therapies: cognitive behavioural therapy (CBT) — the most evidence-based psychological approach; addresses pain catastrophising, fear-avoidance, and maladaptive pain beliefs; mindfulness-based stress reduction (MBSR) as alternative; pain education/neuroscience education reduces fear and catastrophising. Multidisciplinary pain programmes: for medium-high risk and refractory patients — combined physical, psychological, and occupational rehabilitation. Pharmacological: duloxetine (60-120 mg daily) — SNRI with evidence for chronic low back pain, recommended by NICE 2023; low-dose amitriptyline (10-30 mg nocte) — for sleep and central sensitisation; NSAIDs (ibuprofen, naproxen) — short-term only, with gastroprotection; avoid opioids (weak efficacy in CLBP, significant harm — dependence, sedation, increased falls). Interventional: epidural steroid injections (ESI) for acute-on-chronic radicular pain — short-term benefit only; facet joint injections; radiofrequency denervation (medial branch blocks) for confirmed facet joint pain; spinal cord stimulation (SCS) for refractory neuropathic/radicular pain. Surgery: lumbar discectomy for disc herniation with persistent radiculopathy not responding to 6-12 weeks conservative management — 85% improvement in leg pain. Spinal decompression for stenosis.

Untreated or poorly managed chronic back pain carries significant long-term consequences beyond the pain itself. Functional disability and deconditioning: progressive loss of strength, flexibility, and cardiovascular fitness from activity avoidance creates a vicious cycle — greater deconditioning leads to more pain on any activity, further limiting mobility. Psychological complications: depression affects up to 50% of chronic back pain sufferers; anxiety disorders, post-traumatic stress disorder (PTSD), and sleep disorders are common comorbidities; untreated mental health conditions worsen pain prognosis substantially. Opioid dependence: patients on long-term opioids for chronic LBP frequently develop physiological dependence, tolerance, and opioid-induced hyperalgesia — a paradoxical worsening of pain sensitivity. Neurological complications: untreated cauda equina syndrome from disc herniation causes permanent bladder and bowel incontinence, saddle anaesthesia, and lower limb paralysis; progressive radiculopathy without treatment can result in permanent neurological deficit including foot drop. Chronic widespread pain sensitisation: prolonged untreated LBP can spread beyond the lumbar region as central sensitisation develops, potentially evolving into generalised pain disorders. Work disability and socioeconomic impact: chronic LBP is the leading cause of long-term work absence and early retirement in working-age adults, with profound economic consequences.

Regular physical activity is the strongest evidence-based preventive strategy — people who exercise regularly have 33% lower risk of developing chronic back pain. Core strengthening, yoga, and Pilates are particularly beneficial for spinal stability. Maintain a healthy weight — each unit increase in BMI increases LBP risk; obesity worsens disc degeneration and increases mechanical loading. Ergonomic workplace adjustments: sit-stand desks, lumbar-supported seating, workstation assessment — important for sedentary occupations. Correct manual handling techniques: bend at the knees, not the back, when lifting. Smoking cessation: smoking impairs disc nutrition (avascular discs depend on diffusion from vertebral endplates — impaired by smoking-related vascular disease). Good sleep hygiene: poor sleep is both a consequence and driver of chronic pain. Psychological wellbeing: address depression and anxiety early — mental health comorbidities are strong predictors of chronification. Avoid prolonged rest or avoidance of activity — guided graduated return to activity is preferred.

Seek emergency care immediately (call 999 or attend A&E) for: sudden onset bladder or bowel dysfunction (difficulty passing urine, urinary retention, or faecal incontinence) with back pain and leg symptoms — this indicates cauda equina syndrome, requiring emergency MRI and neurosurgical review within hours. Seek urgent same-day GP review for: new back pain with fever (spinal infection); back pain in someone with known cancer (vertebral metastasis); rapid-onset severe pain after minor trauma in an elderly or osteoporotic patient (compression fracture); back pain with significant bilateral leg weakness; or blood in urine with back pain (renal causes). Routine GP appointment for: back pain lasting more than 6 weeks not improving; pain causing significant disability; or pain associated with morning stiffness above 30 minutes lasting years (inflammatory spondyloarthropathy). Physiotherapy referral without waiting for GP approval is appropriate for most non-specific LBP.