Spinal fracture

Overview

A spinal fracture is a break in one or more vertebrae - ranging from osteoporotic compression fractures to unstable fracture-dislocations. The key clinical question is always: is the spinal cord or nerve roots at risk?

Presentation

•Localised spinal pain - midline tenderness on palpation

•Limb weakness, sensory loss/paraesthesia - indicates cord or root involvement

•Bladder/bowel dysfunction - red flag for cord or cauda equina compromise

•Saddle anaesthesia (perianal sensory loss) - pathognomonic of cauda equina syndrome

•Neurogenic shock - bradycardia, hypotension, warm dry peripheries, priapism; due to loss of sympathetic outflow in high thoracic/cervical injury

UMN vs LMN signs in spinal injury

Feature	UMN (cord, above L1)	LMN (cauda equina, at/below L1)
Tone	Spasticity	Flaccidity
Reflexes	Hyper-reflexia, clonus	Hyporeflexia
Plantars	Upgoing (Babinski +ve)	Downgoing
Wasting	Absent early	Present

⚠️

Spinal shock vs neurogenic shock: Spinal shock is transient flaccid paralysis and areflexia immediately after cord injury (UMN signs emerge later as it resolves). Neurogenic shock is a haemodynamic emergency (bradycardia + hypotension) from sympathetic loss - needs fluid resuscitation and vasopressors.

Investigations

🥇 First-line

•Plain X-ray (AP and lateral) - initial screening for thoracic/lumbar injuries; may miss posterior element fractures

•First-line (cervical/high suspicion): CT spine - preferred for suspected cervical fracture and any thoracolumbar injury with abnormal X-ray or high clinical suspicion; superior bony detail

🏆 Gold standard

•MRI whole spine - mandatory when neurological deficit present, suspected cord/cauda equina compromise, or no bony injury on CT; evaluates cord, discs, ligaments, and epidural haematoma

🎯

Cervical spine clearance: Apply NEXUS criteria or Canadian C-Spine Rule. If alert, not intoxicated, no midline cervical tenderness, no focal neurology, and no distracting injury - clinical clearance without CT is appropriate. If criteria not met, CT C-spine is required.

Management

All suspected spinal fractures

1. 1Immobilise spine - cervical collar and spinal board pre-hospital; log-roll technique
2. 2ABCDEs - treat neurogenic shock with IV fluids and vasopressors if bradycardia + hypotension
3. 3CT/MRI to define injury and stability
4. 4Bloods: FBC, U&E, CRP, bone profile

↓

Neurologically intact / stable fracture

Conservative: analgesia, immobilisation/bracing, physiotherapy; treat underlying osteoporosis (alendronic acid + calcium/vitamin D); consider vertebroplasty/kyphoplasty if VCF pain persists >6 weeks

Neurological deficit / unstable fracture

Urgent surgical decompression and stabilisation; emergency surgery for epidural haematoma or acute neurological deterioration; transfer to regional spinal cord injuries centre

Complications

•Cauda equina syndrome - surgical emergency; bladder/bowel dysfunction and saddle anaesthesia

•Autonomic dysreflexia - injury at/above T6; triggered by noxious stimuli below lesion; severe hypertension, headache, sweating above lesion, bradycardia; can cause seizures and stroke

•Respiratory failure - high cervical injury (above C4) may require ventilatory support

•VTE - DVT prophylaxis with LMWH required due to immobility

•Progressive kyphosis and height loss - complication of multiple osteoporotic VCFs

🚨

Neurogenic shock vs hypovolaemic shock: both cause hypotension, but hypovolaemia causes tachycardia while neurogenic shock causes bradycardia - do not miss this distinction in a trauma patient.

Prognosis

•Ambulant at presentation → ~80% remain ambulant after treatment

•Complete cord injury (absent motor and sensory function below level) → poor prognosis for neurological recovery

•Incomplete cord injury → significant improvement possible

•Osteoporotic VCFs → increased risk of future fractures and independently associated with increased mortality (respiratory complications from kyphosis); treat underlying osteoporosis

Key Anatomy

•Spinal cord ends at ~L1 (conus medullaris); below L1, nerve roots form the cauda equina

•Injury above L1 → cord damage → upper motor neurone (UMN) signs

•Injury at/below L1 → cauda equina → lower motor neurone (LMN) signs

•Denis three-column model - disruption of ≥2 columns = mechanical instability

Fracture Types

Key fracture patterns

Fracture	Mechanism	Key feature
Burst fracture	High-energy axial load (diving, fall from height)	Bone driven into spinal canal - unstable
Chance fracture	Flexion-distraction (lap-belt injury)	Through posterior elements
Vertebral compression fracture (VCF)	Osteoporosis; trivial/no trauma	Wedge-shaped; anterior body height loss
Ankylosing spondylitis fracture	Hyperextension; even minor falls	High instability and cord injury risk