What is Affected by Lower Cervical Spine Injury with Spinal Cord Involvement
Lower cervical spine injuries with spinal cord involvement (C6-C7) primarily affect respiratory function through impaired diaphragmatic and intercostal muscle function, though to a lesser degree than upper cervical injuries, and carry significant risk of permanent neurological deficits including quadriplegia if secondary injury occurs. 1
Primary Systems Affected
Respiratory System
- Lower cervical injuries (C6-C7) reduce vital capacity by more than 50%, though less severely than upper cervical injuries (C2-C5) 1
- Respiratory muscle paralysis or weakness occurs due to intercostal muscle denervation, while diaphragmatic function may be partially preserved depending on exact injury level 1
- Patients experience difficulty clearing bronchial secretions due to impaired cough mechanics 1
- Respiratory complications are common, with approximately 40% of patients presenting with high fever and breathing difficulty 2
Neurological Function
- Risk of permanent quadriplegia is the most devastating consequence, occurring when secondary spinal cord injury develops from manipulation or movement of an unstable spine 1
- Sensory deficits affecting the torso and upper extremities are characteristic findings 1
- Muscle weakness involving upper extremities and potentially lower extremities depending on injury completeness 1
- Tingling in extremities is a common presenting symptom 1
Cardiovascular System
- Blood pressure instability requiring careful hemodynamic management to prevent secondary injury 1
- Neurogenic shock can occur with loss of sympathetic tone 3
Critical Clinical Distinctions
Lower vs. Upper Cervical Injuries
Lower cervical injuries (C6-C7) have better respiratory prognosis than upper cervical injuries (C2-C5), with different management implications 1:
- Tracheostomy timing differs: Lower cervical injuries should only receive tracheostomy after one or more extubation failures, whereas upper cervical injuries warrant early tracheostomy within 7 days 1
- Ventilatory weaning is more likely to succeed in lower cervical injuries 1
- Lying position is often better tolerated than sitting due to gravity effects on abdominal contents and inspiratory capacity 1
Risk of Secondary Injury
Iatrogenic Worsening
- Approximately 2% baseline risk of cervical spine injury exists after blunt trauma serious enough to require imaging, tripled to 6% with craniofacial injury 1
- Historically, 10% of initially neurologically intact patients developed new deficits during emergency care before standardized protocols 4
- When cervical fractures are missed, 67% of patients suffer neurological deterioration 4
- Improper manipulation during transport or examination can convert incomplete injury to complete quadriplegia 1
Long-term Functional Impact
Disability and Quality of Life
- Approximately 25% of patients with cervical spinal cord injury are discharged to dedicated nursing facilities, indicating severe permanent disability 5
- Lifetime care costs for tetraplegia are estimated at US$1 million per patient 5
- The prognosis is particularly poor when combined with head injury 5
- Only 60.3% of patients show at least one Frankel grade improvement with optimal treatment 2
Common Pitfalls in Management
Immobilization Errors
- Rigid cervical collars alone do not adequately restrict displacement and may cause paradoxical movement at injury sites 4
- Prolonged immobilization beyond 48-72 hours increases morbidity including pressure sores, increased intracranial pressure, and aspiration pneumonia 4
- Manual stabilization of the head to minimize motion is more effective than devices alone 1