Residency · Residency · Neurosurgery
Spinal Cord Injury: Acute Management and Neuroprotection
Introduction
Spinal cord injury is a devastating neurological condition affecting approximately 18,000 new individuals annually in the United States. The majority of injuries occur in young males due to motor vehicle accidents, falls, and violence. Acute management focuses on preventing secondary injury through hemodynamic optimization, surgical decompression, and emerging neuroprotective strategies. Neurosurgeons play a central role in early decision-making regarding imaging, stabilization, and operative intervention.
Epidemiology and Mechanisms
The incidence of spinal cord injury in the United States is approximately 54 cases per million population. The mean age at injury is 43 years, and 78 percent of patients are male. Motor vehicle accidents account for 38 percent of injuries, followed by falls at 30 percent, violence at 13 percent, and sports-related injuries at 8 percent. Cervical injuries account for approximately 60 percent of cases, thoracic injuries for 30 percent, and lumbar injuries for 10 percent. Complete injuries classified as AIS A account for approximately 40 percent, while incomplete injuries carry greater recovery potential.
Primary vs. Secondary Injury
Primary injury refers to the immediate mechanical disruption of neural tissue through compression, distraction, laceration, or transection. Secondary injury is a cascade of ischemia, inflammation, excitotoxicity, oxidative stress, and apoptosis that extends damage over hours to weeks following the initial insult. The therapeutic window for neuroprotection targets this secondary injury cascade, making early intervention critical.
Initial Assessment
Prehospital Care
Spinal immobilization with a cervical collar and backboard is applied for all suspected spinal cord injuries, with care taken to avoid excessive spinal movement during extraction. The initial assessment follows the ABCDE approach: airway with cervical spine protection, breathing, circulation, disability, and exposure. Intubation may be required for high cervical injuries involving C3 through C5, where phrenic nerve function is compromised. Hypotension must be avoided aggressively, as SCI patients are at risk for neurogenic shock from loss of sympathetic tone, which causes bradycardia and vasodilation.
Neurological Examination
The ASIA/ISNCSCI examination provides a standardized assessment of motor and sensory levels. The ASIA Impairment Scale classifies injuries as A for complete, B for sensory incomplete, C for motor incomplete with fewer than 50 percent of key muscles grading 3 or above, D for motor incomplete with 50 percent or more of key muscles grading 3 or above, and E for normal.
| AIS Grade | Classification | Definition | |
|---|---|---|---|
| A | Complete | No motor or sensory function preserved in sacral segments S4-S5 | |
| B | Sensory incomplete | Sensory but no motor function preserved below the level, including S4-S5 | |
| C | Motor incomplete | Motor function preserved below the level; <50% of key muscles grade ≥3 | |
| D | Motor incomplete | Motor function preserved below the level; ≥50% of key muscles grade ≥3 | |
| E | Normal | Motor and sensory function normal | The neurological level of injury is defined as the most caudal segment with normal motor and sensory function bilaterally. Sacral sparing, which includes perianal sensation, voluntary anal contraction, and deep anal pressure, is the key determinant distinguishing complete from incomplete injury. Serial examinations are essential because neurological status may evolve over time. |
Spinal Cord Injury Syndromes
Central cord syndrome presents with upper extremity weakness greater than lower extremity weakness and typically results from hyperextension injury in older adults with cervical spondylosis. Brown-Sequard syndrome produces ipsilateral motor and proprioception loss with contralateral pain and temperature loss, resulting from hemisection injury. Anterior cord syndrome causes loss of motor function, pain, and temperature sensation with preserved proprioception and carries the worst prognosis among incomplete syndromes. Posterior cord syndrome is rare and involves loss of proprioception with preserved motor and pain/temperature function. Conus medullaris syndrome presents with bladder and bowel dysfunction, saddle anesthesia, and lower extremity weakness. Cauda equina syndrome produces asymmetric lower extremity weakness, radicular pain, and bladder retention.
| Syndrome | Mechanism | Motor Deficit | Sensory Deficit | Prognosis |
|---|---|---|---|---|
| Central cord | Hyperextension (elderly with spondylosis) | UE > LE weakness | Variable | Moderate (LE recovers first) |
| Brown-Sequard | Hemisection (penetrating trauma) | Ipsilateral loss | Ipsilateral proprioception loss; contralateral pain/temp loss | Best among incomplete |
| Anterior cord | Anterior spinal artery occlusion, flexion | Complete motor loss below level | Loss of pain/temp; preserved proprioception | Worst among incomplete |
| Posterior cord | Rare; posterior column injury | Preserved | Loss of proprioception/vibration; preserved pain/temp | Good |
| Conus medullaris | Injury at L1-L2 vertebral level | LE weakness, symmetric | Saddle anesthesia | Variable |
| Cauda equina | Injury below conus | LE weakness, asymmetric | Radicular pattern | Variable (LMN recovery) |
Imaging
CT of the entire spine is the first-line imaging modality for acute trauma, providing rapid evaluation of fractures, dislocations, and alignment. MRI of the spine is essential for evaluating spinal cord compression, hemorrhage, edema, disc herniation, and ligamentous injury. MRI findings predict outcome: intramedullary hemorrhage is associated with worse prognosis, while edema alone is more favorable. CT angiography should be considered for vertebral artery injury in cervical spine fractures involving the foramen transversarium.
Acute Medical Management
Hemodynamic Optimization
Mean arterial pressure goals of 85 mmHg or greater should be maintained for 5 to 7 days following injury according to AO Spine guidelines. Vasopressors, with norepinephrine preferred, are used for neurogenic shock to maintain spinal cord perfusion. Even brief hypotensive episodes worsen secondary injury and must be avoided aggressively. ICU-level monitoring with an arterial line for continuous blood pressure management is required.
Neurogenic Shock Management
Neurogenic shock must be distinguished from hemorrhagic shock. Neurogenic shock presents with bradycardia and warm extremities due to loss of sympathetic tone, whereas hemorrhagic shock produces tachycardia and cold extremities. Atropine is used for symptomatic bradycardia, and vasopressors are employed for refractory hypotension. Temporary pacing may be necessary for severe bradyarrhythmias in high cervical injuries.
VTE Prophylaxis
SCI patients carry among the highest VTE risk of any patient population. Pharmacologic prophylaxis with low-molecular-weight heparin should be initiated within 24 to 72 hours unless contraindicated by active hemorrhage. Mechanical prophylaxis with pneumatic compression devices serves as an adjunct. Duration of prophylaxis should be at least 3 months post-injury for motor-complete injuries.
Surgical Management
Timing of Decompression
Early surgical decompression within 24 hours is associated with improved neurological outcomes. The STASCIS trial demonstrated that a 2-grade AIS improvement is more likely with early surgery. Ultra-early decompression within 12 hours may provide additional benefit, though definitive evidence is still evolving. Surgery is indicated for ongoing spinal cord compression with neurological deficit, unstable spinal fractures, and progressive neurological deterioration. The timing of surgery for central cord syndrome is debated, though early surgery is increasingly favored over conservative management.
Surgical Approaches
The anterior approach includes corpectomy and discectomy with fusion for ventral compression. The posterior approach involves laminectomy and posterior instrumented fusion for dorsal compression or instability. A combined anterior-posterior approach is used for severe instability or circumferential compression. The goal in all cases is to achieve adequate decompression and stabilization to prevent further injury.
Neuroprotective Strategies
Current Evidence
Methylprednisolone was previously the standard of care based on the NASCIS II and III trials but is now not recommended as standard treatment due to marginal benefit and significant side effects including infection, gastrointestinal hemorrhage, and hyperglycemia. Some guidelines consider it an option only within 8 hours of injury. Riluzole is a sodium channel blocker that reduces excitotoxicity, and phase III trials have been completed showing potential benefit in cervical SCI. Minocycline is an anti-inflammatory antibiotic with neuroprotective properties currently undergoing phase III trials. Systemic or local hypothermia to reduce metabolic demand has shown promising preliminary results but is not yet standard practice.
Emerging Therapies
Stem cell therapies including mesenchymal stem cells and neural progenitor cells have multiple trials in progress. Epidural electrical stimulation has shown remarkable ability to restore volitional movement in chronic complete SCI. Chondroitinase ABC is an enzyme that degrades glial scar tissue with preclinical success. Anti-Nogo antibodies target myelin-associated inhibitors of axonal regeneration and represent another promising avenue of research.
Clinical Pearls
Sacral sparing, including perianal sensation and voluntary anal contraction, is the single most important finding distinguishing complete from incomplete SCI and carries major prognostic implications. Maintaining MAP of 85 mmHg or greater for 5 to 7 days in acute SCI optimizes spinal cord perfusion and reduces secondary injury. Early surgical decompression within 24 hours is associated with improved neurological outcomes and should be prioritized when feasible. Methylprednisolone is no longer recommended as standard of care for acute SCI, and its use remains controversial. Neurogenic shock presents with bradycardia and hypotension, distinct from hemorrhagic shock, and requires vasopressor support.
References
- Fehlings MG, Vaccaro A, Wilson JR, et al. Early versus delayed decompression for traumatic cervical spinal cord injury (STASCIS). PLoS One. 2012;7(2):e32037.
- Ahuja CS, Wilson JR, Nori S, et al. Traumatic spinal cord injury. Nat Rev Dis Primers. 2017;3:17018.
- Fehlings MG, Tetreault LA, Aarabi B, et al. A clinical practice guideline for the management of acute spinal cord injury. Global Spine J. 2017;7(3 Suppl):209S-264S.
- Angeli CA, Boakye M, Morton RA, et al. Recovery of over-ground walking after chronic motor complete spinal cord injury. N Engl J Med. 2018;379(13):1244-1250.