Spinal injury

Spinal injury is damage to the vertebral column, its ligaments and discs, the spinal cord, the conus medullaris or the cauda equina, ranging from an isolated stable fracture to a complete cord transection.

Clinical relevance. Road collisions, falls and sport are the main causes, with a peak in young men and a second peak in older adults after low energy falls. A spinal injury is present in up to 5% of major blunt trauma patients, and about 10 to 20% have a second, non-contiguous spinal fracture. A missed unstable injury can convert an incomplete deficit into a complete one.

Pathophysiology. Primary injury occurs at impact through compression, flexion, extension, rotation, distraction or penetration. Secondary injury follows within minutes to days from ischaemia, oedema, hypotension, hypoxia, inflammation and mechanical compression by bone, disc or haematoma.

Classification by level. Cervical (occiput to C7, including atlanto-occipital, C1, C2 odontoid and hangman fractures, and subaxial injuries C3 to C7), thoracic, thoracolumbar junction (T11 to L2, the commonest site of fractures in the trunk), lumbar and sacral.

Classification by stability. Stable injuries (isolated vertebral body compression, spinous or transverse process fractures) rarely displace.

Unstable injuries can displace with movement. They include burst fractures with posterior wall retropulsion, flexion distraction injuries, fracture dislocations, ligamentous disruption, and injuries involving two or three columns.

Classification by neurological injury (impairment scale).

• A: complete, no motor or sensory function in the sacral segments S4 to S5.
• B: sensory incomplete, sensation but no motor function preserved distal to the level, including the sacral segments.
• C: motor incomplete, more than half of key muscles distal to the level have a grade under 3.
• D: motor incomplete, at least half of key muscles distal to the level have a grade of 3 or more.
• E: normal.

Incomplete cord syndromes.

• Central cord syndrome: arms weaker than legs, from hyperextension in cervical stenosis.
• Anterior cord syndrome: loss of motor, pain and temperature with preserved dorsal column function.
• Brown-Sequard syndrome: ipsilateral weakness and loss of proprioception with contralateral loss of pain and temperature.
• Posterior cord syndrome (rare), conus medullaris syndrome and cauda equina syndrome.

Key distinctions. Spinal shock (areflexia and flaccid paralysis distal to the lesion, lasting hours to weeks, ended by return of the bulbocavernosus reflex) differs from neurogenic shock (hypotension with bradycardia from loss of sympathetic tone in lesions at T6 or higher). Spinal cord injury without radiographic abnormality occurs mainly in children and in older adults with canal stenosis.

History.

• Mechanism and energy (fall height, collision speed, diving, axial load, hyperextension, penetrating wound), position found, time of injury, and prehospital immobilisation.
• Neck or back pain, weakness, numbness, tingling, bladder or bowel disturbance, priapism, difficulty breathing, and symptoms at the scene that have resolved (transient deficit).
• Anticoagulants, bone disease (osteoporosis, ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis), known canal stenosis, previous spinal surgery, malignancy, intoxication and head injury.
• In children: developmental level and history inconsistent with the injury.

Examination.

• Primary survey with manual in-line stabilisation: airway, breathing (diaphragmatic breathing with paradoxical abdominal movement suggests a cervical lesion), circulation (hypotension with warm peripheries and bradycardia suggests neurogenic shock), disability and exposure with temperature control.
• Inspect and palpate the entire spine by log roll with a team of at least four (step deformity, midline tenderness, bruising, gibbus, wounds). Examine the back, axillae, perineum and scalp in penetrating injury.
• Neurological examination: assess sensation to light touch and pinprick in each dermatome, proprioception, reflexes, and tone.
• Test motor power in the key muscles: C5 elbow flexors, C6 wrist extensors, C7 elbow extensors, C8 finger flexors, T1 finger abductors, L2 hip flexors, L3 knee extensors, L4 ankle dorsiflexors, L5 long toe extensors, S1 ankle plantar flexors.
• Sacral function: perianal sensation, voluntary anal contraction, anal tone on rectal examination, and the bulbocavernosus reflex. Priapism, a distended bladder and absent anal wink are common in complete injury.
• Record the neurological level (lowest segment with normal function on both sides), the grade, and the time of examination, and repeat at regular intervals.

Red flags.

• Any new motor or sensory deficit, or a progressive deficit.
• Midline spinal tenderness, step deformity or a palpable gap.
• Hypotension with bradycardia and warm peripheries (neurogenic shock) or hypoxia with falling vital capacity (cervical lesion).
• Priapism, urinary retention, loss of anal tone, saddle numbness (conus or cauda equina injury).
• Penetrating injury near the spine, or a foreign body in situ.
• Dangerous mechanism: fall over 1 metre or 5 stairs, axial load to the head, collision at over 100 km/hour, rollover, ejection, motorised recreational vehicle or bicycle collision.
• Age 65 years or more, paraesthesia in the limbs, or reduced consciousness with a high energy mechanism.
• Severe osteoporosis, ankylosing spondylitis or other fused spine (fractures after minimal trauma and delayed deficit).
• Fractures of the foramen transversarium, C1 to C3, or subluxation (vertebral artery injury).

Special groups. Children have a higher fulcrum (C2 to C3) and ligamentous laxity, and need appropriate padding for a large head and weight based doses. Older adults with canal stenosis can develop a central cord syndrome with minor trauma. Intoxicated, sedated and unconscious patients cannot be clinically cleared. Pregnancy needs left lateral tilt after 20 weeks with the spine protected.

Traumatic spinal column injury. Vertebral compression fracture, burst fracture, flexion distraction (Chance) fracture, fracture dislocation, facet dislocation (unilateral or bilateral), odontoid fracture, Jefferson fracture, hangman fracture. Occipital condyle fracture, atlanto-occipital dissociation, sacral fracture, spinous or transverse process fracture, traumatic disc herniation, ligamentous injury without fracture.

Traumatic neurological injury. Complete and incomplete cord injury, central cord syndrome, Brown-Sequard syndrome, anterior cord syndrome, conus medullaris and cauda equina injury. Nerve root avulsion, brachial plexus injury, spinal epidural haematoma, cord contusion with concussion, transient neurapraxia.

Vascular injury. Vertebral artery dissection, carotid artery dissection, anterior spinal artery infarction, aortic injury accompanying thoracic spine fracture.

Non-traumatic and pathological causes mimicking or accompanying injury. Osteoporotic fracture, pathological fracture (metastasis, myeloma, lymphoma), spinal infection (vertebral osteomyelitis, discitis, epidural abscess, tuberculosis). Spontaneous epidural haematoma, transverse myelitis, Guillain-Barre syndrome, acute disc prolapse, spinal stenosis, syringomyelia, demyelination, cord infarction.

Soft tissue and functional causes. Cervical or lumbar muscle strain, whiplash associated disorder, ligament sprain, facet joint injury, rib injury, retroperitoneal haematoma, conversion disorder, and intoxication masking symptoms.

Other conditions that cause limb weakness or shock in trauma. Head injury, haemorrhagic shock, hypoglycaemia, stroke, peripheral nerve injury, compartment syndrome, tension pneumothorax with hypotension.

Step 1. Primary survey and resuscitation with spinal precautions. Neurogenic shock is a diagnosis of exclusion after haemorrhage is excluded, since most hypotension in trauma is from bleeding.

Step 2. Decide who needs imaging.

• Imaging is required for any patient with a focal neurological deficit, midline tenderness, an unreliable examination (reduced consciousness, intoxication, distracting injury), or a high risk feature.
• A validated clinical decision rule allows clearance without imaging in an alert, sober, cooperative patient. Its criteria are no midline tenderness, no focal deficit, normal alertness, no intoxication and no painful distracting injury.
• An alternative validated rule applies to alert adults with a stable injury. It starts with high risk factors (age 65 or over, dangerous mechanism, paraesthesia).
• Then it checks low risk factors: simple rear end collision, sitting position in the emergency department, ambulatory at any time, delayed onset of neck pain, absence of midline tenderness. These allow safe assessment of active range of movement.
• Image if the patient cannot rotate the neck 45 degrees to each side.
• In obtunded patients, a normal high quality CT of the cervical spine allows collar removal in most centres, with MRI added for persistent neurological signs or high suspicion.

Step 3. Imaging.

• CT of the whole spine from the head to the pelvis with sagittal and coronal reconstructions is the first test in major trauma. It is more sensitive than plain radiographs for fractures.
• MRI is required for any neurological deficit, discordant clinical and CT findings, suspected ligamentous injury, disc herniation, epidural haematoma or cord compression. It shows cord oedema, haemorrhage and transection, and is used for prognosis.
• CT angiography of the neck for fractures through the foramen transversarium, C1 to C3 fractures, subluxation, or signs of vertebral artery injury (posterior circulation symptoms, Horner syndrome).
• Plain radiographs only when CT is not available.
• Flexion extension views are not used in the acute phase because of risk of cord injury. They have a role only in awake, cooperative patients with persistent pain after normal CT or MRI, under senior supervision.
• Chest, abdomen and pelvic imaging for associated injury. Ultrasound for the bladder and for free fluid.

Step 4. Laboratory tests: full blood count, urea, creatinine, electrolytes, glucose, coagulation, group and crossmatch, blood gas and lactate, creatine kinase, troponin when there is chest trauma, and toxicology. Check vital capacity and arterial blood gases in cervical lesions.

Step 5. Classify the injury (level, grade, stability, impairment grade) and repeat the neurological examination to look for progression.

Interpretation. Loss of sacral sparing and persistent complete loss at 72 hours predict a poor prognosis for recovery of motor function, while sacral sparing and incomplete injury predict a better outcome.

Cord haemorrhage and a long segment of oedema on MRI carry a worse prognosis.

Limitations. CT misses cord and ligament injury and some disc injury. MRI can overestimate ligament injury, is difficult in unstable or ventilated patients, and is not available in all centres. Flexion extension views are unreliable in spasm. Clinical clearance cannot be done in intoxicated or sedated patients.

Immediate priorities. Resuscitate (airway with manual in-line stabilisation, oxygen, access, haemorrhage control), protect the spine, and maintain oxygenation and perfusion to prevent secondary injury. Call senior surgical, orthopaedic or neurosurgical staff early.

Immobilisation.

• Apply a correctly sized rigid collar and head blocks or sandbags with tape. Use manual in-line stabilisation if a collar cannot be applied or the patient is agitated (a collar in a struggling patient can worsen the injury).
• Use a scoop stretcher or vacuum mattress and log roll with at least four people.
• Remove the patient from a hard spinal board as soon as possible (within 30 minutes if feasible) to reduce pressure injury. Children and older adults with fixed deformity are placed in the position found with padding.
• In penetrating injury without a deficit, routine collar placement is not required.

Airway and breathing.

• Intubate for airway compromise, Glasgow Coma Scale of 8 or less, hypoxia, hypoventilation, or for a cervical lesion with falling vital capacity. Use rapid sequence induction with manual in-line stabilisation and video laryngoscopy.
• Use ketamine 1 to 2 mg/kg IV or etomidate 0.3 mg/kg IV, with rocuronium 1.2 mg/kg IV.
• Suxamethonium 1 to 1.5 mg/kg IV is safe in the first 48 hours. It must be avoided from about 48 hours to 6 months after injury because of life threatening hyperkalaemia.
• Monitor forced vital capacity every 4 hours in cervical and high thoracic lesions. Ventilation is considered when vital capacity is under 15 mL/kg (or under 1 litre), when PaCO2 rises, or when the patient is exhausted. Early physiotherapy, assisted cough and tracheostomy planning follow.
• Beware of bradycardia and cardiac arrest during tracheal suction in high cervical lesions: pre-oxygenate and have atropine ready.

Circulation: neurogenic shock.

• First exclude and treat haemorrhage with blood products and tranexamic acid when appropriate. Isotonic crystalloid 250 to 500 mL boluses (avoid excess, which causes pulmonary oedema).
• Target a mean arterial pressure of 85 to 90 mmHg for 5 to 7 days in acute cord injury.
• Use noradrenaline 0.05 to 0.5 micrograms/kg/minute IV (titrate every 5 to 10 minutes; central access preferred; monitor arterial pressure, cardiac output and peripheral perfusion) or dopamine 5 to 20 micrograms/kg/minute IV when bradycardia predominates.
• Symptomatic bradycardia: atropine 0.5 to 1 mg IV every 3 to 5 minutes (maximum 3 mg), or glycopyrronium 0.2 mg IV. Persistent bradycardia needs an infusion of adrenaline 0.05 to 0.5 micrograms/kg/minute or temporary pacing.

Analgesia and neuroprotection.

• Paracetamol 1 g orally or IV every 6 hours (maximum 4 g daily; 3 g daily if weight under 50 kg, malnutrition, alcohol excess or liver disease).
• Morphine 2 mg IV boluses every 5 minutes titrated to pain (reduce in older adults and kidney impairment; monitor sedation, respiratory rate and bowel function).
• Neuropathic pain: gabapentin 100 to 300 mg orally at night, increased every 1 to 3 days to 300 to 600 mg three times daily (maximum 3.6 g daily), monitoring sedation.
• Reduce gabapentin in kidney impairment, for example 200 to 700 mg twice daily when creatinine clearance is 30 to 59 mL/minute.
• High dose methylprednisolone is not given routinely: the benefit is weak and the risks (infection, gastrointestinal bleeding, hyperglycaemia, wound problems, and death in head injury) are significant.

Surgical decisions.

• Urgent decompression and stabilisation within 24 hours for incomplete cord injury with persistent compression, a progressive deficit, unstable fracture dislocation, spinal epidural haematoma, or a bilateral facet dislocation.
• Closed reduction with traction in an awake patient under specialist control is an option in cervical facet dislocations.
• Cauda equina syndrome with a compressive lesion needs decompression within 24 to 48 hours.
• Central cord syndrome without instability: medical management with early mobilisation, with early or delayed surgery decided by the degree of stenosis and the neurological course.
• Stable thoracolumbar compression fractures without deficit: analgesia, early mobilisation with or without a brace for 6 to 12 weeks, and assessment for osteoporosis.
• Odontoid fractures, hangman fractures and Jefferson fractures: collar or halo immobilisation or surgery depending on displacement and stability.

Associated care.

• Pressure area care with turning every 2 hours (a specialist mattress), skin checks at every turn, and avoidance of heat loss.
• Bladder: indwelling catheter with monitoring of urine output; later intermittent catheterisation.
• Bowel: stop opioids when possible, glycerol suppository 4 g rectally or bisacodyl 10 mg suppository every 1 to 2 days, and manual evacuation when required. Nasogastric tube for ileus, which is common for the first days.
• Stress ulcer prophylaxis: omeprazole 40 mg IV or orally once daily (monitor magnesium and sodium over weeks).
• Venous thromboembolism prophylaxis: intermittent pneumatic compression at once.
• Add enoxaparin 40 mg subcutaneously once daily (20 mg daily if CrCl 15 to 30 mL/min; weight based adjustment in obesity; monitor platelets from day 4). Start within 24 to 72 hours when bleeding is controlled and imaging shows no progressing epidural haematoma.
• Continue prophylaxis for at least 8 to 12 weeks in complete cord injury.
• Maintain temperature, glucose 6 to 10 mmol/L, nutrition within 24 to 48 hours, and early rehabilitation. Psychological support from the outset.

Autonomic dysreflexia (cord lesion at T6 or higher, usually after the spinal shock phase). A sudden rise in systolic pressure of 20 to 40 mmHg over baseline with headache, sweating, flushing proximal to the lesion, and bradycardia.

• Sit the patient upright, loosen tight clothing and stockings, measure blood pressure every 2 to 5 minutes, and find the trigger.
• Triggers: bladder (check catheter for blockage, flush or replace with 2 to 3 mL of lidocaine 2% gel), bowel (impaction), skin (pressure sore, ingrowing toenail), fracture or other visceral cause.
• If systolic pressure remains 150 mmHg or more after the trigger is removed, give one of the following.
• Glyceryl trinitrate 400 to 800 micrograms sublingually (repeat every 5 minutes; maximum 3 doses; avoid within 24 hours of a phosphodiesterase inhibitor; monitor for hypotension).
• Captopril 25 mg orally (repeat after 30 minutes; maximum 50 mg; reduce in kidney impairment).
• Nifedipine immediate release 10 mg orally (swallowed whole; repeat after 30 minutes).

Monitoring. Neurological examination at least every 4 hours in the first 72 hours and with any change, continuous electrocardiogram and arterial pressure in cervical and high thoracic lesions, forced vital capacity every 4 hours, urine output hourly, temperature, blood glucose, bowel function, skin inspection and daily weight.

Referral and escalation. Spinal surgery (orthopaedic or neurosurgical) for all unstable injuries and neurological deficit. Critical care for cervical and high thoracic cord injury, ventilation, and vasopressors. Transfer early to a specialist spinal injury unit after stabilisation. Rehabilitation, urology, occupational therapy and psychology.

Admission criteria. Any spinal fracture other than a minor stable injury, any neurological deficit, unreliable examination, unstable vital signs, pain needing parenteral analgesia, and suspected vertebral artery injury.

Discharge and safety netting. Discharge after clearance with a normal examination and pain controlled on oral analgesia. Patients return for new weakness, numbness, bladder or bowel dysfunction, saddle numbness, increasing pain, fever, or neck stiffness. Review in clinic for fractures managed without surgery with repeat imaging at 1 to 2 weeks.