Spinal Cord Injury: Intro, Syndromes, & Acute Management

Introduction to Spinal Cord Injury (SCI) and Key Terminology

  • Tetraplegia: A condition where all four limbs are affected, occurring with injuries to the cervical segments of the spinal cord.

  • Paraplegia: A condition where the lower extremities are affected, occurring with injuries to the thoracic, lumbar, or sacral segments.

  • Orthopedic Level of Injury: Defined as the spinal segment(s) where bony and/or soft tissue structure compromise has occurred as a result of an injury. It may involve multiple levels and segments and applies exclusively to traumatic SCI.

  • Neurologic(al) Level of Injury (NLI): The most caudal level of the spinal cord in which both sensory and motor function is intact on both sides of the body. This is a single, specific level.

  • Traumatic SCI (tSCI): Injury resulting from external, physical trauma or damage to the spine and spinal cord.

  • Non-Traumatic SCI: Injury not caused by external trauma. Causes include:

    • Congenital or genetic disorders: Spina Bifida, hereditary spastic paraplegia, Spinal Muscular Atrophy.

    • Chiari malformations.

    • Spinal myelopathy.

    • Metabolic syndromes: Such as severe vitamin B12B_{12} deficiency.

    • Vascular disorders: Hemorrhage, stroke, or vascular malformation.

    • Inflammatory or neurologic disorders: Multiple Sclerosis (MS), Transverse Myelitis (TM), Neuromyelitis Optica (NMO).

    • Space-occupying lesions.

Impact, Epidemiology, and Statistics of SCI

  • Incidence and Prevalence (NSCISC 2024):

    • Incidence: Approximately 5454 cases per 11 million persons in the US, totaling about 18,00018,000 new traumatic cases per year (excluding those who die at the scene).

    • Prevalence: Approximately 305,000305,000 persons are currently living with tSCI in the US.

  • Demographics:

    • Average age at injury: 4343 years (an increase from 2929 since 20152015).

    • Age distribution: Bimodal peaks at 1515-2929 years old and greater than 6565 years old.

    • Gender: Approximately 79%79\% of new cases are male, representing a 4:14:1 male-to-female ratio.

  • Primary Causes of SCI:

    1. Motor Vehicle Accidents (MVAs).

    2. Falls.

    3. Acts of Violence.

    4. Sports/Recreation.

    5. Medical/Surgical.

    6. Other.

  • Sports & Recreation (Age 30 and Under):

    • Diving is a primary cause; the "FEET FIRST" safety campaign is emphasized.

    • Other activities: Snow skiing, winter sports, surfing, horseback riding, trampolines, football (#1 contact sport), wrestling, gymnastics, and cheerleading.

  • Neurological Extent of Lesion:

    • Incomplete tetraplegia: 47.4%47.4\%

    • Incomplete paraplegia: 20%20\%

    • Complete paraplegia: 19.7%19.7\%

    • Complete tetraplegia: 12.3%12.3\%

    • Normal (full recovery by discharge): less than 1%1\%

  • Common Levels of Injury:

    • The five most common levels are C5C5, C4C4, C6C6, T12T12, and L1L1.

    • The upper and mid-thoracic areas are less commonly injured due to the stabilization provided by the rib cage.

Primary Mechanisms of Injury

  • Flexion:

    • Etiology: Head-on collisions (head strikes windshield/steering wheel), or blow to the back of the head/trunk.

    • Fractures: Wedge fracture of the anterior vertebral body (compression).

    • Associated Injuries: Tearing of posterior ligaments, fractures of posterior elements (spinous process, laminae, pedicles), and disk disruption. High percentage occurs at C4C4-C7C7 and T12T12-L2L2.

  • Compression:

    • Etiology: Vertical or axial blows (diving, surfing, falling objects); often associated with flexion.

    • Fractures: Concave endplate fracture, explosion/burst fracture (comminuted), or teardrop fracture.

    • Associated Injuries: Bone fragments may lodge in the cord; disk rupture.

  • Hyperextension:

    • Etiology: Strong posterior force (rear-end collisions), falls with the chin hitting a stationary object (common in the elderly).

    • Fractures: Fractures of posterior elements (spinous processes, laminae, facets), avulsion fracture of the anterior vertebrae.

    • Associated Injuries: Rupture of the anterior longitudinal ligament and disk. Primarily involves cervical lesions.

  • Flexion-Rotation:

    • Etiology: Posterior-to-anterior force directed at a rotated column (e.g., rear-end collision while looking at the driver).

    • Fractures: Posterior pedicles, articular facets, and laminae. Extremely unstable if ligaments rupture.

    • Associated Injuries: Rupture of posterior/interspinous ligaments; subluxation/dislocation of facet joints; facets may lock in the thoracolumbar region.

Financial Impact of Spinal Cord Injury (2023 Dollars)

  • High Tetraplegia (C1C1-C4C4):

    • First Year: $1,369,755\$1,369,755

    • Each Subsequent Year: $237,862\$237,862

    • Lifetime (at age 25): $6,077,646\$6,077,646

  • Low Tetraplegia (C5C5-C8C8):

    • First Year: $989,768\$989,768

    • Each Subsequent Year: $145,918\$145,918

    • Lifetime (at age 25): $4,440,708\$4,440,708

  • Paraplegia:

    • First Year: $667,569\$667,569

    • Each Subsequent Year: $88,433\$88,433

    • Lifetime (at age 25): $2,971,942\$2,971,942

  • Motor Functional at Any Level (AIS DAIS \, D):

    • First Year: $447,037\$447,037

    • Each Subsequent Year: $54,298\$54,298

    • Lifetime (at age 25): $2,030,446\$2,030,446

Immediate Acute Management and Clinical Shocks

  • Imaging:

    • X-Ray/CT: Used for bony anatomy.

    • MRI: Used for soft tissue assessment.

  • Spinal Shock:

    • Definition: Transient neural depression with loss of all spinal reflexes below the level of injury.

    • Sensation/Motor: Flaccid paralysis (hypotonia) and sensory loss.

    • Bulbocavernosis Reflex (BCR - S2S2-S4S4): To test, provide sensory stimulus (squeeze glans penis/clitoris or tug on catheter). Normal response is anal sphincter contraction.

    • Note: Return of BCR indicates the resolution of spinal shock.

  • Neurogenic Shock:

    • Definition: Interruption of sympathetic pathways causing decreased vasomotor tone and decreased input to the heart.

    • Result: Hypotension and bradycardia. Treated with vasopressors.

  • Care Continuum: Immediate emergency management (immobilization/surgery) \rightarrow ICU \rightarrow Rehabilitation (Inpatient/Outpatient) \rightarrow Home or Long-Term Care.

ASIA Impairment Scale (AIS) and Lesion Designation

  • Motor Level: The most caudal level with normal motor function bilaterally (can have 2 levels, one for each side).

  • Sensory Level: The most caudal level with normal sensory function bilaterally (can have 2 levels, one for each side).

  • Neurologic Level of Injury (NLI): The most caudal of the 4 motor and sensory levels where function is normal on both sides of the body.

  • AIS Levels:

    • A (Complete): No motor or sensory function in sacral segments S4S4-S5S5.

    • B (Sensory Incomplete): Sensation is preserved below the NLI and includes S4S4-S5S5, but no motor function is preserved more than 33 levels below the motor level on either side.

    • C (Motor Incomplete): Motor function is preserved at the most caudal sacral segments OR the patient meets sensory incomplete criteria and has motor sparing more than 33 levels below the motor level. Less than half of key muscles below NLI have a grade ≥3\ge 3.

    • D (Motor Incomplete): Same as C, but at least half (or more) of key muscle functions below NLI have a grade ≥3\ge 3.

    • E (Normal): Prior deficits have resolved; sensory and motor function are normal in all segments.

Clinical Syndromes of Incomplete SCI

  • Central Cord Syndrome:

    • Most common; often seen in older adults after falls (hyperextension).

    • UE motor loss > LE motor loss.

    • Bowel/bladder/sexual function often preserved due to sacral tract sparing; increased likelihood of ambulation.

  • Brown-Séquard Syndrome:

    • Caused by hemi-section of the spinal cord (e.g., penetrating injury).

    • Ipsilateral loss: Motor function, light touch, and proprioception.

    • Contralateral loss: Pain and temperature.

  • Anterior Cord Syndrome:

    • Caused by hyperflexion or anterior spinal artery stroke (affects anterior 2/32/3 of cord).

    • Loss: Motor function and pain/temperature below the lesion.

    • Sparing: Light touch and proprioception.

  • Posterior Cord Syndrome:

    • Rarest; affects posterior 1/31/3 of cord.

    • Loss: Light touch and proprioception.

    • Sparing: Motor function and pain/temperature.

    • Note: Movement is non-functional and hard to coordinate; functional ambulation is unlikely.

  • Conus Medullaris Syndrome:

    • Injury at T11T11-L2L2 (rostral); results in mixed Upper Motor Neuron (UMN) and Lower Motor Neuron (LMN) signs.

  • Cauda Equina Syndrome:

    • Medical emergency; injury to "horse's tail" (below L1L1).

    • Symptoms: Low back pain, saddle anesthesia, sudden LE weakness, bowel/bladder changes.

    • Results in LMN signs (peripheral nerve injury).

Clinical Considerations and Complications

  • Assessment & Intervention:

    • Assessment: ISNCSCI (ASIA) exam, MMT, Sensory Testing, Modified Ashworth Scale, Reflexes, Skin assessment.

    • Intervention: PROM/AROM, electrical stimulation, restorative vs. compensatory strategies, positioning, patient education.

  • Orthostatic Hypotension:

    • Symptom: Drop in BP upon position changes.

    • Management: Monitor vitals, slow progression (tilt table), compression garments, abdominal binders.

  • Respiratory Dysfunction:

    • Effects: Decreased lung capacity, weakened muscles, paradoxical breathing, decreased cough effectiveness, risk of pneumonia and sleep apnea.

    • PT Interventions: Breathing exercises, assisted coughing, chest wall mobilization, abdominal binders to support the diaphragm.

  • Thermoregulation:

    • Disconnect between brain (hypothalamus) and body below LOI. Risk increases with higher and more complete lesions.

  • Autonomic Dysreflexia (AD):

    • Occurs in lesions at T6T6 or above. Massive sympathetic response to noxious stimuli below LOI.

    • Symptoms: Hypertension (HTN), headache, bradycardia, sweating/flushing above LOI, cold/clammy skin below LOI.

    • Causes: #1 Bowel/bladder distension (kinked catheter). Also UTIs, pressure sores, ingrown toenails, tight clothing.

    • Action: RECOGNIZE symptoms, check for blockage/stimuli, sit the patient UPRIGHT to lower BP, and seek medical help if unresolved.

  • Bowel/Bladder Dysfunction:

    • Spastic/Reflexive (Above T12T12): UMN; bladder contracts in response to pressure. Managed with intermittent catheterization (IC) and digital stimulation.

    • Flaccid (Below L1L1): LMN; bladder does not contract and will leak when overfilled. Managed with IC, Credé/Valsalva maneuvers, and manual rectal clears.

  • Secondary Complications: Pneumonia, pressure sores, Deep Vein Thrombosis (DVT), joint contractures, bone density loss (fractures), heterotopic ossification (hips/knees), and chronic UTIs.

SCI Outcome Measures

  • Specific to SCI:

    • ASIA Impairment Scale (AIS).

    • Spinal Cord Independence Measure (SCIM).

    • Walking Index for Spinal Cord Injury (WISCI + WISCI II).

    • Spinal Cord Injury Functional Ambulation Inventory (SCI-FAI).

    • Wheelchair Skills Test & Wheelchair Users Shoulder Pain Index (WUSPI).

    • Tetraplegia Hand Activity Questionnaire.

    • Quadriplegia Index of Function.

  • Commonly used General Measures:

    • 66 minute walk test, 1010 meter walk test, Berg Balance Test, Functional Independence Measure (FIM), TUG, Dynamic Gait Index, Modified Ashworth Scale, and Tardieu Scale.