Cervical Disc Herniation

Cervical disc herniation is the displacement of disc material into the spinal canal or the neural foramen of the cervical spine, which causes cervical radiculopathy (neck and arm pain with sensory and motor features in a nerve root distribution) and sometimes cord compression and myelopathy.

The annual incidence of cervical radiculopathy is about 83 cases in 100 000 people each year, with a peak between 50 and 54 years and a slight male predominance. The C7 root is affected in about 45 to 60% (the C6 to C7 disc), then C6 (C5 to C6, 20 to 25%), C8 and C5. A soft disc herniation is typical in younger adults after lifting or minor trauma, while foraminal narrowing from osteophytes (spondylotic radiculopathy) is more common in older adults. Smoking, heavy lifting, vibration and frequent driving are risk factors.

The prognosis is good: 75 to 90% improve without surgery within months. Complications are persistent arm pain, motor weakness, cervical myelopathy, and chronic neck pain.

Pathophysiology.

A fissure in the annulus allows the nucleus to move posterolaterally into the foramen, where it compresses the root and dorsal root ganglion. The compression and the local inflammatory response (cytokines, phospholipase A2) produce radicular pain, and ischaemia and oedema of the root produce sensory and motor loss. Large central herniations compress the cord. Many herniations regress in 6 to 12 months through resorption.

Unilateral neck pain radiating to the shoulder, scapular region and arm in a dermatomal pattern, with paraesthesia and sometimes weakness. The patient may hold the hand on the head (shoulder abduction relief sign).

• C5: shoulder pain; deltoid and biceps weakness.
• C6: thumb and index finger paraesthesia; weak biceps and wrist extension; reduced biceps and brachioradialis reflexes.
• C7: middle finger paraesthesia; weak triceps, wrist flexion and finger extension; reduced triceps reflex.
• C8: ring and little finger paraesthesia; weak finger flexion and hand intrinsics.

Spurling test (neck extension with lateral flexion and axial load, specific but not sensitive), shoulder abduction relief sign, neck distraction test, and upper limb tension tests. Examine for myelopathy (hyperreflexia, Hoffmann sign, gait disorder, clumsy hands) and for shoulder and peripheral nerve disease.

• The diagnosis is mainly clinical, and imaging is needed when symptoms persist beyond 6 weeks, a motor deficit or myelopathy is present, or warning features exist (fever, weight loss, cancer history, trauma, progressive deficit).
• MRI of the cervical spine: the herniation, root compression, cord signal change and foraminal narrowing.
• CT (bone osteophytes, foraminal stenosis) or CT myelography if MRI is contraindicated; flexion and extension radiographs for alignment and instability.
• Electromyography and nerve conduction studies to separate peripheral entrapment (carpal tunnel and cubital tunnel syndromes) and a double crush.
• Blood tests (full blood count, ESR, CRP) only if infection or cancer is suspected; diagnostic selective nerve root block in selected cases.

Differential diagnosis.

• Carpal tunnel syndrome, cubital tunnel syndrome and thoracic outlet syndrome.
• Rotator cuff disease and shoulder impingement.
• Brachial neuritis (neuralgic amyotrophy), herpes zoster and angina.
• Cervical myelopathy, Pancoast tumour, syringomyelia, spinal infection and tumour.

Most patients recover with non-operative care. Surgery is for severe or progressive deficit and persistent pain.

Non-operative treatment (6 to 12 weeks).

• Reassurance and activity as tolerated; a soft collar only for 1 to 2 weeks for comfort; physiotherapy with posture correction, deep neck flexor strengthening and mobilisation; cervical traction has limited evidence.
• Paracetamol 1 g orally every 6 hours as needed (maximum 4 g daily; 3 g daily when weight is under 50 kg, with chronic alcohol use or hepatic impairment).
• Ibuprofen 400 mg orally every 8 hours with food (maximum 1200 mg daily) or naproxen 500 mg orally every 12 hours with food (maximum 1000 mg daily) for 1 to 2 weeks, with omeprazole 20 mg orally once daily in patients over 65 or with ulcer risk; avoid with eGFR under 30 mL/min/1.73 m2, peptic ulcer, heart failure, uncontrolled hypertension or anticoagulant use.
• Neuropathic pain: gabapentin 300 mg orally at night, increased by 300 mg every 1 to 3 days to 300 to 600 mg three times daily (maximum 3600 mg daily; reduce at creatinine clearance under 60 mL/min), or pregabalin 75 mg orally at night or twice daily, increased to 150 mg twice daily (maximum 300 mg twice daily); amitriptyline 10 mg orally at night, increased to 25 to 50 mg (avoid with recent myocardial infarction, arrhythmia, glaucoma and urinary retention); duloxetine 30 mg orally once daily for 1 week, then 60 mg once daily (maximum 120 mg daily).
• Oral prednisolone 30 mg once daily for 5 to 7 days is used for severe acute radicular pain in some centres; the evidence is limited, and it is avoided in diabetes and infection.
• Short course of oral morphine 5 to 10 mg every 4 hours as needed for up to 5 to 7 days for severe pain (start 2.5 to 5 mg with age over 75 or eGFR under 30 mL/min/1.73 m2).
• Cervical epidural steroid injection (interlaminar or transforaminal) carries a rare but catastrophic risk of spinal cord or brainstem infarction with particulate steroids: use only non-particulate dexamethasone 4 to 10 mg, with fluoroscopic image direction and contrast, by an experienced operator, and avoid with infection, uncontrolled diabetes, and unheld anticoagulants (hold apixaban or rivaroxaban for 72 hours and warfarin for 5 days with INR under 1.5).

Surgery (progressive or severe motor deficit, myelopathy, or disabling radicular pain after 6 to 12 weeks).

• Anterior cervical discectomy and fusion (plate and cage or graft): relief of arm pain in about 90%; pseudarthrosis 2 to 10%; adjacent segment disease about 2 to 3% a year.
• Cervical disc arthroplasty for single level disease in selected patients, preserving motion.
• Posterior laminoforaminotomy for lateral soft disc herniation or foraminal stenosis, avoiding fusion; recurrence 3 to 5%.
• Complications: dysphagia (up to 50% early and about 5% persistent after anterior surgery), recurrent laryngeal nerve palsy 1 to 3%, epidural haematoma with airway compromise, C5 root palsy, dural tear, Horner syndrome, oesophageal injury (rare), infection.

Operative antibiotic prophylaxis. Cefazolin 2 g intravenously (3 g when weight is 120 kg or over) within 60 minutes before incision as a single dose; with severe penicillin allergy, vancomycin 15 mg/kg intravenously starting 90 to 120 minutes before incision as a single dose.

Perioperative adjuncts. Dexamethasone 8 mg intravenously once at induction may reduce nausea, airway swelling and early dysphagia (monitor glucose in diabetes). Ondansetron 4 mg intravenously at the end of surgery (avoid with prolonged QT). Enoxaparin only for high risk patients: 40 mg subcutaneously once daily started 24 to 48 hours after surgery for 7 to 14 days (20 mg once daily at creatinine clearance under 30 mL/min).

Analgesia after surgery. Paracetamol 1 g orally every 6 hours; oral morphine 5 to 10 mg every 4 hours as needed for up to 3 days; laxative; soft diet, and lozenges for dysphagia.

Monitoring. Neurological examination and airway checks (neck swelling, voice change, stridor) in the first 24 hours after surgery. Review at 2 weeks, 6 weeks, 3 months and 12 months, with radiographs to show fusion. In non-operative patients, review at 2 to 6 weeks and 12 weeks; repeat the neurological examination for new myelopathic signs.

Referral and escalation. Refer to a spinal surgeon for progressive weakness, myelopathy, or pain persisting at 6 to 12 weeks. Emergency referral for rapidly progressive deficit, new bladder or bowel loss, or suspected infection or tumour.

Special groups.

• Young adults: soft disc herniations regress most often; prefer non-operative care.
• Pregnancy: non-operative management; MRI without gadolinium; avoid NSAIDs in the third trimester.
• Smokers: higher risk of non-union after fusion; support with cessation (nicotine replacement or varenicline).
• Myelopathy: needs urgent surgical assessment.