What is the level of spinal cord injury associated with upper flaccidity and positive movement of lower extremities?

Central Cord Syndrome: Upper Flaccidity with Preserved Lower Extremity Movement

Upper flaccidity with preserved lower extremity movement is characteristic of central cord syndrome, which typically occurs due to a cervical spinal cord injury affecting the central portion of the spinal cord. 1

Pathophysiology and Mechanism

Central cord syndrome (CCS) is the most common incomplete spinal cord injury syndrome and is characterized by:

• Disproportionately greater weakness in the upper extremities compared to the lower extremities
• Upper extremity flaccidity with preserved lower extremity motor function
• Varying degrees of sensory loss below the level of injury
• Potential bladder dysfunction (typically urinary retention)

The syndrome typically results from:

• Hyperextension injury to the cervical spine, particularly in individuals with pre-existing cervical spondylosis or congenitally narrow spinal canal 1
• Compression of the central portion of the spinal cord between hypertrophic spondylotic disc-osteophyte complexes anteriorly and buckled ligamentum flavum posteriorly 1
• Injury to the centrally located cervical motor tracts that control upper extremity function 2

Clinical Significance and Prognosis

The prognosis for central cord syndrome is generally better than for complete spinal cord injuries:

• Recovery typically follows a pattern of lower extremities first, then bladder function, and finally upper extremities 1
• The majority of recovery occurs within the first 9-12 months post-injury, with relative plateau reached by 12-18 months 3
• Younger patients and those with milder initial disability have better chances of achieving full recovery 1

Diagnostic Considerations

When evaluating a patient with suspected central cord syndrome:

1. Neurological examination:

   • Document disproportionate weakness of upper versus lower extremities
   • Assess for sensory deficits below the level of injury
   • Evaluate bladder function

2. Imaging:

   • MRI is essential for evaluating soft tissue injuries, including ligamentous damage, disc herniations, and spinal cord compression 4
   • High-resolution CT is preferred for assessing bony elements 4
   • Look for evidence of pre-existing cervical spondylosis or congenitally narrow canal

Management Priorities

1. Immediate stabilization:

   • Immobilize the cervical spine to prevent further injury
   • Optimize cardiorespiratory and hemodynamic parameters 1
   • Transfer to a specialized acute SCI unit when possible, as this has been associated with reduced morbidity and mortality 1

2. Surgical considerations:

   • Early surgical decompression (within 24 hours) may be beneficial for improving neurological outcomes 1
   • Surgical decision-making should consider the degree of spinal cord compression, presence of instability, and neurological status

3. Medical management:

   • Thromboprophylaxis is recommended due to high risk of venous thromboembolism in SCI patients 1
   • Consider pharmacological interventions for spasticity if it develops during recovery (e.g., tizanidine) 5

Common Pitfalls and Caveats

• Misdiagnosis: Central cord syndrome can be mistaken for cruciate paralysis, which also presents with upper extremity weakness but has a different pathophysiological basis 2
• Delayed treatment: Only 20-50% of SCI patients are transferred to appropriate centers for surgical decompression within 24 hours of injury, potentially missing the critical therapeutic window 1
• Incomplete assessment: Failure to recognize central cord syndrome may lead to delayed intervention and suboptimal outcomes
• Overlooking associated injuries: Cervical SCI patients often have concomitant traumatic brain injuries that can complicate assessment and management 1

Central cord syndrome represents a distinct pattern of incomplete cervical spinal cord injury with characteristic clinical presentation and generally favorable prognosis compared to complete spinal cord injuries.