Spinal Cord Injuries

Traumatic spinal cord injury has an incidence of roughly 10 to 50 per million per year, with a bimodal age distribution. Young men are injured in road traffic crashes, violence, sport and diving. Older adults are injured in falls, often with pre-existing cervical spondylosis. Cervical injuries account for about half of cases, and the thoracolumbar junction (T12 to L2) is the next most frequent site.

Primary injury is the immediate mechanical insult from contusion, compression, laceration or distraction. Secondary injury evolves over hours to days:

• Ischaemia and loss of autoregulation.
• Glutamate excitotoxicity and calcium influx.
• Free radical damage and lipid peroxidation.
• Inflammation, oedema and apoptosis of oligodendrocytes.

This secondary phase is the target of early haemodynamic and surgical management.

Common patterns of bony and ligamentous injury

• C1: Jefferson burst fracture.
• C2: odontoid fractures (type II is the most common and most prone to non-union) and hangman fracture.
• Subaxial cervical: facet dislocation (unilateral or bilateral), flexion teardrop, burst fractures.
• Thoracolumbar: burst fractures, Chance (flexion distraction) fractures and fracture dislocations.

Associated injuries include head injury in 25 to 50%, blunt cervical vascular injury, chest and abdominal trauma, and non-contiguous spinal fractures in 10 to 20%. Children can have spinal cord injury without radiographic abnormality because of ligamentous laxity.

Neurological classification is by the neurological level (the most caudal segment with normal function) and the ASIA impairment scale:

• A: complete, with no sacral sparing.
• B: sensory incomplete, with sacral sensory sparing and no motor function below the level.
• C: motor incomplete, with more than half of key muscles below the level at grade under 3.
• D: motor incomplete, with at least half of key muscles at grade 3 or more.
• E: normal.

Prognosis depends on the initial grade

• ASIA A: roughly 10 to 20% convert to incomplete, and ambulation is rare.
• ASIA B: about 30 to 50% walk, with better odds when pinprick sensation is preserved in the sacral segments.
• ASIA C and D: most regain functional walking, with younger patients doing best.

The leading causes of death in the chronic phase are pneumonia, septicaemia, pulmonary embolism and cardiovascular disease.

Acute presentation reflects level and completeness

• Pain at the injury site, midline tenderness, step deformity, and distracting injuries that mask symptoms.
• Weakness or paralysis with a sensory level, flaccid areflexia in spinal shock, and priapism.
• Urinary retention and absent anal tone, with loss of bulbocavernosus reflex during spinal shock.

Level based function

• C1 to C3: ventilator dependence, no limb function.
• C4: diaphragm and neck function, shoulder shrug. Respiratory support is often required.
• C5: elbow flexion (biceps) and shoulder abduction.
• C6: wrist extension, giving tenodesis grasp.
• C7: elbow extension (triceps) and finger extension.
• C8 to T1: finger flexion and hand intrinsics.
• T1 to T12: trunk and intercostal function, with abdominal muscle innervation from T6.
• L2 to L4: hip flexion and knee extension.
• L5 to S1: ankle dorsiflexion and plantarflexion.

Systemic effects in cervical and high thoracic injuries

• Respiratory: diaphragmatic breathing with paradoxical chest movement, vital capacity reduced to 20 to 30% of predicted in C5 to C6 injury, weak cough, and atelectasis.
• Cardiovascular: neurogenic shock with hypotension and bradycardia, orthostatic hypotension, and autonomic dysreflexia with systolic pressure rising 20 to 40 mmHg above baseline from noxious stimuli below the lesion.
• Other: poikilothermia, paralytic ileus, gastric stasis, and neurogenic bladder and bowel.

Red flags requiring urgent action are ascending deficit, rising sensory level, respiratory fatigue, and a cardiovascular collapse that does not fit haemorrhage. Any unconscious trauma patient is assumed to have a spinal injury until cleared.

Initial assessment follows trauma principles with manual in-line stabilisation, followed by a full neurological examination documented by the standardised ASIA examination: key muscle power (C5 to T1, L2 to S1), light touch and pinprick across 28 dermatomes, voluntary anal contraction and deep anal pressure.

Clinical clearance in alert, sober patients without distracting injury uses validated rules:

• Imaging is not needed when there is no midline tenderness, no focal deficit, normal alertness, no intoxication, no distracting injury, and pain free active rotation of 45 degrees.
• High risk factors mandating imaging include age 65 or over, dangerous mechanism, and paraesthesias in the limbs.

Imaging

• CT of the entire spine (reconstructed from trunk CT in major trauma) is the primary tool for fractures and alignment. It has largely replaced plain films.
• MRI of the spine as soon as feasible in any patient with a neurological deficit, for cord oedema, haemorrhage, epidural haematoma, disc herniation and ligamentous disruption. Intramedullary haemorrhage and long segment oedema predict poor recovery.
• CT angiography of the neck for blunt cervical vascular injury when there are cervical fractures extending into the foramen transversarium, subluxation, or C1 to C3 fractures.

Laboratory and monitoring

• Blood gas, lactate, haemoglobin, creatinine, and CK in prolonged immobilisation.
• Serial vital capacity and negative inspiratory force in cervical injuries.
• Continuous ECG and arterial line monitoring for the first 5 to 7 days.
• Post void residual and later urodynamics.

Prehospital and resuscitation

• Rigid collar or head blocks, a flat firm board with minimal log roll, and early removal from the board to prevent pressure injury.
• Airway: intubate early in high cervical injuries and in respiratory fatigue. Use manual in-line stabilisation with video laryngoscopy or fibreoptic technique. Succinylcholine is safe only in the first 48 to 72 hours, because afterwards receptor upregulation risks fatal hyperkalaemia. Use rocuronium 1.2 mg/kg instead.
• Avoid hypotension and hypoxia at all times. Exclude haemorrhage first, since neurogenic shock is a diagnosis of exclusion.
• Maintain MAP at 85 to 90 mmHg for 5 to 7 days with fluids and norepinephrine 0.05 to 0.5 mcg/kg/min.
• Methylprednisolone is not recommended. The high dose regimen (30 mg/kg bolus then 5.4 mg/kg/h for 23 hours) increases infection and gastrointestinal bleeding without reliable neurological benefit.

Reduction and surgery

• Awake cervical facet dislocation: closed reduction with skull tongs (Gardner-Wells) traction, starting at about 10 lb and adding 5 lb every 10 to 15 minutes with serial neurological checks and lateral imaging, up to a limit of about 5 lb per spinal level above the injury. Obtain MRI beforehand when feasible to look for disc herniation, or proceed to open reduction.
• Early decompression and stabilisation within 24 hours is favoured for incomplete injuries and for persistent cord compression. Immediate surgery is needed for progressive deficit, an epidural haematoma or unreducible dislocation.
• Stable fractures without compression (some odontoid and burst fractures) may be treated with a halo vest, cervical orthosis (4 to 12 weeks) or thoracolumbar brace.

Respiratory care

• Intubation or ventilation when vital capacity falls below 15 mL/kg (or under about 1 L), with early tracheostomy anticipated in C5 and above.
• Chest physiotherapy, mechanically assisted cough, abdominal binder, lung protective ventilation with tidal volumes 8 to 10 mL/kg ideal body weight (higher volumes are used in tetraplegia), and weaning with progressive ventilator free breathing.
• Phrenic nerve or diaphragm pacing in selected patients with intact phrenic nuclei.

Prophylaxis and systemic care

• Thromboprophylaxis: enoxaparin 40 mg SC daily (30 mg twice daily is an alternative) started within 72 hours of haemostasis, with compression devices, continued for 8 to 12 weeks in motor complete injury. Inferior vena cava filters are reserved for contraindication to anticoagulation.
• Omeprazole 20 to 40 mg daily or IV pantoprazole 40 mg daily for stress ulcer prophylaxis in the acute phase.
• Pressure injury prevention: turn every 2 hours, pressure redistribution mattress, and daily skin inspection.
• Nutrition: early enteral feeding, with higher protein targets (1.5 to 2 g/kg/day) in the catabolic phase.

Blood pressure and heart rate

• Symptomatic bradycardia: atropine 0.5 to 1 mg IV, with aminophylline or temporary pacing in refractory cases. Suctioning can provoke severe bradycardia.
• Chronic orthostatic hypotension: compression stockings, abdominal binder, midodrine 5 to 10 mg three times daily (last dose before 6 pm to avoid supine hypertension), fludrocortisone 0.1 to 0.2 mg daily.
• Autonomic dysreflexia: sit upright, loosen clothing, drain the bladder, and disimpact the bowel. If systolic pressure remains above 150 mmHg, give nifedipine 10 mg (bite and swallow) or glyceryl trinitrate 0.4 mg sublingually.

Bladder, bowel and sexual function

• Intermittent catheterisation every 4 to 6 hours (volumes under 500 mL) is preferred over indwelling catheters.
• Detrusor overactivity: oxybutynin 5 mg two to three times daily, or mirabegron 25 to 50 mg daily, or intradetrusor onabotulinumtoxinA 200 units for refractory cases.
• Bowel programme: scheduled suppository (bisacodyl 10 mg) or digital stimulation, with docusate and senna, every 24 to 48 hours.
• Erectile dysfunction: sildenafil 50 to 100 mg an hour before activity, intracavernosal alprostadil, or vacuum devices. Assisted ejaculation and fertility techniques are available.

Late complications

• Spasticity: baclofen 5 mg three times daily titrated up to 80 mg/day, tizanidine 2 mg at night titrated to 36 mg/day, dantrolene 25 mg daily titrated to 100 mg four times daily, botulinum toxin for focal groups, and intrathecal baclofen for severe cases.
• Neuropathic pain: gabapentin 300 mg at night titrated to 3600 mg/day, pregabalin 150 to 600 mg/day, duloxetine 60 mg daily, amitriptyline 10 to 75 mg at night.
• Heterotopic ossification: range of motion exercises, indomethacin 25 mg three times daily, and etidronate 20 mg/kg/day for 2 weeks then 10 mg/kg/day for 10 weeks in selected patients. Surgical excision when mature.
• Osteoporosis: vitamin D 1000 to 2000 IU daily, calcium, and bisphosphonates for fragility fractures.
• Post traumatic syringomyelia: new pain or ascending deficit, treated surgically.
• Mental health: screen for depression and anxiety. Sertraline 50 to 200 mg daily is reasonable.

Rehabilitation and prevention

• Multidisciplinary spinal rehabilitation from the first stable week, with wheelchair provision, functional electrical stimulation, and activity based therapy.
• Annual influenza vaccination, pneumococcal vaccination, and annual skin, renal tract (ultrasound or renal scan) and cardiovascular review.