What are the potential morbidities associated with a subluxation of C1-C2 in a pediatric patient?

Potential Morbidities of C1-C2 Subluxation in Pediatric Patients

C1-C2 subluxation in pediatric patients carries significant risk of spinal cord compression leading to neurological injury, chronic myelopathy if undetected, respiratory failure in severe cases, and permanent functional impairment or death if not promptly diagnosed and appropriately managed. 1

Neurological Complications

Acute Spinal Cord Injury

• Spinal cord compression at the C1-C2 level is the most serious acute complication, occurring in approximately two-thirds of pediatric patients with C1-C2 injuries, particularly those with odontoid fractures 1
• Neurological deficits range from mild weakness to complete quadriplegia depending on the degree of cord compression 1, 2
• Respiratory failure requiring mechanical ventilation can occur due to high cervical cord involvement, with documented mortality in severe cases 1

Chronic Neurological Sequelae

• Chronic myelopathy develops when C1-C2 subluxation goes undetected or inadequately treated, presenting as progressive weakness, spasticity, and functional decline 1
• Persistent spastic quadriparesis has been documented in patients with delayed diagnosis or inadequate treatment 1
• Chronic neck pain and progressive torticollis can result if the subluxation becomes fixed (atlantoaxial rotatory fixation) 3, 4

Age-Specific Injury Patterns

Children Under 13 Years

• Higher incidence of atlantoaxial dislocation without fracture due to ligamentous laxity, incomplete ossification, and large head-to-body ratio 1, 5
• Paradoxically, these patients are more likely to be neurologically intact at presentation compared to older children with fractures 1
• However, the risk of missed diagnosis is higher due to normal anatomical variants (pseudosubluxation, widened atlantodental interval) that can mask pathology 6, 5

Children Over 13 Years

• Higher incidence of type II odontoid fractures rather than pure ligamentous injury 1
• Greater likelihood of presenting with neurological deficits (approximately 67% in one series) 1
• Better ossification makes radiographic diagnosis more straightforward 5

Complications from Delayed or Missed Diagnosis

Diagnostic Pitfalls Leading to Morbidity

• Plain radiographs alone miss up to 15% of C1-C2 injuries, with lateral films having only 54.3% sensitivity for cervical injuries 6
• In unconscious or intubated children, lateral radiographs detect only 51.7% of unstable injuries 5
• Normal anatomical variants in children under 8 years can lead to false reassurance and delayed diagnosis 6, 5

Progressive Deformity

• Untreated rotatory subluxation progresses to fixed atlantoaxial rotatory fixation with permanent torticollis and cosmetic deformity 3, 4
• Chronic subluxation can lead to persistent ankylosis even with conservative treatment 7
• Progressive spinal cord compression develops insidiously in chronic cases 2

Functional and Quality of Life Impact

Mobility Restrictions

• Surgical fusion (required in most cases of atlantoaxial dislocation without fracture) results in permanent loss of cervical rotation, which comprises 50% of total neck rotation 1, 2
• Occipital-cervical fusion (sometimes necessary) causes even greater mobility loss and higher nonunion rates 2

Treatment-Related Morbidity

• Halo-vest immobilization (required for 3+ months) causes significant lifestyle disruption in children 1
• Surgical complications include nonunion, hardware failure, and vertebral artery injury 3, 2
• Transoral decompression may be required for malunion cases, adding surgical morbidity 1

High-Risk Populations

Children with certain underlying conditions face substantially elevated risk of both C1-C2 subluxation and associated complications 5, 7:

• Down syndrome (atlantoaxial instability)
• Achondroplasia (foramen magnum stenosis)
• Mucopolysaccharidoses (ligamentous laxity)
• Marfan syndrome (connective tissue abnormality)
• Enthesitis-related arthritis (inflammatory joint destruction) 7
• Chronic systemic glucocorticoid therapy (bone weakening) 5

Mortality Risk

• Death from irreversible respiratory failure occurred in 3 of 22 patients (13.6%) in one pediatric series of C1-C2 injuries 1
• Mortality is highest with complete spinal cord injury at the C1-C2 level affecting respiratory centers 1
• Delayed diagnosis increases mortality risk due to progressive cord compression 1

Prevention of Morbidity

Early recognition and appropriate imaging are essential to prevent complications 6, 5:

• Maintain high clinical suspicion in children with neck pain, torticollis, or neurological symptoms after trauma
• Use CT with sagittal reconstruction when plain films are abnormal or equivocal (false negative rate <0.1%) 6
• Obtain MRI for any neurological deficits, suspected cord compression, or ligamentous injury 6, 5
• Consider dynamic CT and 3D reconstruction for persistent subluxation without pain to assess stability 6, 4
• Evaluate for vertebral artery injury with CTA in fractures involving C1-C3 or transverse foramen 6, 5