Radiculopathy and prolapsed intervertebral disc

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

A disc's annulus may fissure and allow nucleus material to protrude or extrude, irritating and mechanically compressing a root. Cervical radiculopathy often affects C6 or C7; lumbar disease often affects the traversing root below the disc, such as L5 from L4/5 or S1 from L5/S1. Dermatomes and myotomes vary between people, so diagnosis uses a pattern of pain, weakness, reflexes and provocation rather than one patch of altered sensation.

Root disease must be separated from cord, plexus, peripheral nerve, hip or shoulder pathology. C6 weakness affects elbow flexion or wrist extension with reduced biceps or supinator reflex; C7 affects elbow extension and finger extension with reduced triceps reflex. L5 can weaken ankle dorsiflexion and great-toe extension without a reliable reflex; S1 affects plantar flexion with reduced ankle jerk. Upper-motor-neurone signs, a truncal level or sphincter symptoms are not explained by a single uncomplicated root.

Management prioritises natural history and function. Explain that movement is safe within tolerable limits, support return to activity and address sleep, work and psychosocial barriers. NSAIDs may be considered at the lowest effective dose for a short period after risk assessment, while opioids and dependence-forming medicines are restricted. MRI and surgery are not rewards for pain severity; they are used when results will change management and symptoms, examination and anatomy agree.

Key points

Radiculopathy is a nerve-root syndrome producing dermatomal pain or sensory symptoms, myotomal weakness and a corresponding reflex change; pain without objective deficit may still be radicular.
Disc prolapse is one cause among foraminal stenosis, osteophyte, tumour, infection, inflammation and postoperative scar; an MRI disc bulge is common and does not prove symptom causation.
Cervical roots cause neck-to-arm pain, paraesthesia and segmental weakness; lumbar roots cause back-to-leg sciatica, with L5 and S1 common but clinically overlapping.
A positive straight-leg raise reproduces familiar radicular pain below the knee; the crossed test is less sensitive but more specific for a disc-related syndrome.
Check for cervical myelopathy whenever arm radiculopathy is accompanied by gait disturbance, clumsy hands or legs, brisk reflexes, extensor plantars or sphincter change.
Most uncomplicated disc-related radiculopathy improves over weeks with information, continued activity and exercise; prolonged bed rest promotes deconditioning and fear.
NICE advises against routine imaging in non-specialist low-back and sciatica care; MRI is used when serious pathology is suspected or specialist results will change invasive management.
For sciatica, NICE advises against gabapentinoids, other antiepileptics, oral corticosteroids and benzodiazepines because overall benefit is lacking and harm exists.
Consider epidural local anaesthetic plus steroid only for acute severe sciatica through an appropriate service, not routine non-specific back pain.
Spinal decompression is considered when non-surgical treatment has not improved pain or function and radiology is concordant; progressive motor deficit prompts earlier surgical review.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Disc herniation

Annular disruption permits disc material to protrude and inflame or compress a cervical or lumbar nerve root.

Degenerative foraminal narrowing

Osteophytes, facet enlargement and loss of disc height progressively reduce the exit space available to a root.

Tumour, infection and inflammation

Metastasis, nerve-sheath tumour, epidural infection and inflammatory radiculitis cause less common but clinically important root syndromes.

Trauma and postoperative disease

Fracture, traction, scar and recurrent disc disease can injure roots directly or alter foraminal anatomy after intervention.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Mechanical root deformation
Disc, bone, mass or scar compresses a spinal root within the canal or neural foramen at that level.
2
Chemical inflammation
Disc mediators and local immune responses sensitise the root, producing radicular pain even without severe visible compression.
3
Conduction and axonal failure
Persistent pressure impairs blood flow and impulse transmission, causing dermatomal sensory loss, myotomal weakness and reduced reflexes.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Cervical root pattern

Neck pain radiates into one arm with dermatomal paraesthesia, a focal myotomal weakness and reduced biceps, supinator or triceps reflex, often provoked by foraminal loading.

Lumbar root pattern

Back or buttock pain radiates below the knee with cough or strain sensitivity, dermatomal symptoms, L5 dorsiflexion or S1 plantar-flexion weakness and a matching reflex change.

Cauda-equina red flagsRed flag

Bilateral sciatica or progressive weakness accompanies saddle, genital, urinary flow, bowel fullness or sexual dysfunction and requires emergency MRI rather than routine conservative care.

Cervical cord red flagsRed flag

Hand clumsiness, gait disturbance, brisk legs, clonus, extensor plantars or new bladder change with arm symptoms indicates myelopathy beyond an isolated root.

Cancer or infectionRed flag

Unremitting night pain, weight loss, known malignancy, fever, immunosuppression, injecting drug use or recent spinal infection and procedure demands a cause-specific urgent pathway.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Neurological root and cord examinationFirst step
Why
Demonstrate a coherent myotomal, dermatomal and reflex pattern and exclude myelopathy or cauda-equina disease.
Interpretation and limitations
Test several muscles per root, reflexes above and below, gait, plantars and sacral function when indicated; individual dermatome variability means no single sensory spot is diagnostic.
02
Straight-leg raise and crossed raise
Why
Mechanically reproduce familiar lumbosacral radicular pain and support disc-related root irritation.
Interpretation and limitations
Radiation below the knee during limited hip flexion is more relevant than back tightness. The crossed test has lower sensitivity but greater specificity; neither replaces red-flag assessment.
03
MRI spine
Why
Identify concordant disc or foraminal compression when serious pathology is suspected or an injection or operation is being considered.
Interpretation and limitations
Do not image routinely in non-specialist uncomplicated care. Disc bulges are frequent in asymptomatic people, so level, side and root must match the syndrome.
04
Electrodiagnostic studies
Why
Distinguish root disease from entrapment neuropathy, plexopathy or more diffuse neuromuscular disease when localisation remains uncertain.
Interpretation and limitations
EMG may be normal early or in sensory-only radicular pain and does not show cord compression; timing and muscle sampling determine usefulness.
05
Targeted blood and systemic tests
Why
Investigate infection, malignancy, inflammatory disease or metabolic neuropathy when history or examination warrants.
Interpretation and limitations
Inflammatory markers, cultures, myeloma screen, diabetes or other tests are clue driven; routine panels are not needed for a classic improving disc syndrome.
06
Functional and risk assessment
Why
Guide intensity of support and measure whether conservative treatment is restoring participation.
Interpretation and limitations
Record walking, sleep, work, motor deficit, analgesic use and psychosocial obstacles; progression of true weakness overrides a stable pain score.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Mononeuropathy

Weakness and sensation in a named peripheral nerve, including muscles from several roots, supports distal focal nerve disease.

Plexopathy

Patchy severe pain and deficits spanning several roots and terminal nerves suggests plexus inflammation, tumour or trauma.

Myelopathy or cauda-equina syndrome

Brisk legs, gait change, a sensory level or new bladder, bowel, saddle and sexual symptoms indicate a spinal emergency.

Joint and musculoskeletal pain

Local tenderness, restricted passive movement and pain-limited effort without neurological distribution supports shoulder, hip or spinal mechanical disease.

Additional chapter-specific clues

Peripheral mimic

Median, ulnar, fibular or tibial neuropathy, brachial or lumbosacral plexopathy and hip or shoulder disease may resemble one component but have different distributions and provocative findings.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Initial assessmentLocalise and screen dangerFirst stepNeck-to-arm or back-to-leg pain suggests a nerve-root syndrome.

1Define distribution, onset, cough or movement provocation and functional loss, then test myotomes, reflexes, sensation and tension signs and screen cord, cauda-equina, cancer, infection and trauma features.
2Use emergency MRI and specialist routes for red flags; otherwise explain the favourable natural history, encourage normal activity and avoid routine non-specialist imaging.
3Offer goal-based exercise and self-management, review work and sleep and use short, risk-assessed analgesia rather than prolonged bed rest or automatic dependence-forming medicine.

02Persistent disabling symptomsImage only when it changes carePain or function fails to improve after proportionate conservative management or objective weakness progresses.

1AlternativeRe-examine localisation and alternative hip, shoulder, peripheral nerve, cord and systemic causes and confirm adherence and barriers to rehabilitation.
2Refer for specialist assessment and MRI when the result will guide injection or decompression, ensuring that radiological side and level match the clinical root.
3Discuss epidural local anaesthetic and steroid for selected acute severe sciatica or surgery for persistent concordant disability, with expected benefits and procedural risks.

03Motor or sacral progressionEscalate neurological lossEscalationWeakness worsens, becomes bilateral or is joined by myelopathic or sacral autonomic symptoms.

1Repeat and time-document myotomal power, gait, reflexes, plantars, saddle sensation and bladder, bowel and sexual history without waiting for complete paralysis or incontinence.
2Activate emergency cervical cord or cauda-equina MRI and spinal surgical pathways rather than continuing the original routine physiotherapy plan.
3DefinitiveManage retention, falls, analgesia and immobility complications while definitive decompression or cause-specific treatment is arranged.

Key medicines and prescribing safety5 treatments · regimens, roles and cautions

May reduce acute nociceptive and inflammatory pain sufficiently to maintain activity and sleep.

NSAID

Use the lowest effective formulary dose for the shortest possible period after risk assessment.

Consider gastrointestinal, renal, cardiovascular, anticoagulant, pregnancy and older-frailty risks and use gastroprotection where indicated; benefit in sciatica is limited.

Provides temporary analgesia to support movement when safer options cannot be used.

Short-course weak opioid

Consider only for selected acute low-back pain when an NSAID is contraindicated, not tolerated or ineffective.

NICE advises against opioids for chronic sciatica or chronic low-back pain; constipation, sedation, driving impairment, tolerance and dependence require an exit plan.

Avoids ineffective or harmful prescribing based on NICE's overall evidence assessment.

Treatments not recommended for sciatica

Do not initiate gabapentinoids, other antiepileptics, oral corticosteroids or benzodiazepines for routine sciatica.

Review established dependence-forming treatment through shared taper planning rather than abrupt withdrawal; another indication may require a separate decision.

May provide short-term relief in a selected patient and support rehabilitation or defer surgery.

Epidural local anaesthetic and corticosteroid

A specialist uses the locally approved image-guided product and dose for acute severe sciatica.

Not for non-specific back pain; consent includes infection, bleeding, dural puncture, transient neurological effects and uncertain duration, with anticoagulant timing checked.

Treats persistent pain or functional loss despite non-surgical care and urgent progressive motor or cauda-equina compression.

Spinal decompression

The spinal surgeon selects discectomy or decompression according to concordant level, side and anatomy.

Imaging abnormality alone is insufficient; recurrent disc, dural tear, infection, neural injury and incomplete pain relief require shared decision-making.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Persistent weakness and atrophy

Severe axonal loss can leave foot drop, hand weakness and muscle wasting despite resolution of pain or later decompression.

Chronic neuropathic pain

Ongoing root sensitisation causes burning, allodynia, sleep disturbance and work loss, sometimes reinforced by inactivity over time.

Cord or cauda-equina injury

A large central disc may compress the cord or multiple sacral roots, causing irreversible gait and sphincter dysfunction.

Treatment-related harm

Sedating medicines, prolonged bed rest, injection and surgery can cause dependence, deconditioning, bleeding, infection or recurrent symptoms.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Repeat objective myotomal power and reflexes, gait and functional activity rather than judging progression from pain intensity alone.
Ask at each worsening episode about urinary initiation and flow sensation, saddle or genital change, rectal fullness, sexual function and bilateral weakness.
Review NSAID and opioid adverse effects, duration and exit plan and avoid accumulating gabapentinoids, benzodiazepines and steroids for routine sciatica.
Track return to activity, work, sleep and exercise goals and address fear, low mood and occupational barriers that prolong disability.
After injection or surgery, monitor new neurological deficit, infection, headache, bladder change and whether the original target function improved.
Escalate progressive weakness, myelopathic signs, systemic illness or any sacral red flag immediately, even after a previous reassuring scan.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Disc does not equal pain

Protrusions are common in people without symptoms, so concordance among side, root, examination and imaging is essential before an invasive treatment.

L5 has no reliable reflex

Great-toe and ankle dorsiflexion plus sensory and gait findings are more useful than searching for a single routine L5 tendon reflex.

Crossed raise is specific

Raising the unaffected leg and reproducing familiar pain in the affected leg is less common but more specific for disc-related root irritation.

Radiculopathy can be painless

A motor root deficit may remain after pain subsides, so improving pain should not end monitoring of foot drop or hand weakness.

Myelopathy changes the pathway

Brisk legs, plantars, gait or hand clumsiness cannot be explained by one cervical root and demand urgent cord assessment.

Activity is treatment

Graded return to meaningful movement prevents deconditioning and fear, whereas prolonged bed rest generally delays recovery.

11Common pitfallsFrequent interpretation and management errors.

01
Treating an incidental MRI disc bulge as the cause despite a non-concordant side, level or examination.
02
Ordering routine imaging at the first uncomplicated sciatica visit and medicalising common age-related findings.
03
Prescribing gabapentin, pregabalin, oral steroid or benzodiazepine routinely for sciatica despite NICE advice.
04
Missing cervical myelopathy because attention remains on unilateral arm pain.
05
Waiting for urinary incontinence before activating a cauda-equina pathway.
06
Using pain improvement as proof that progressive motor weakness is safe.