Spinal Cord Injuries

Classification Systems

Anatomical Classification

• Tetraplegia: Injury to the cervical spinal cord leading to impairment of function in arms, trunk, legs, and pelvic organs

• Paraplegia: Injury to the thoracic, lumbar, or sacral segments leading to impairment of function in trunk, legs, and pelvic organs (arm function preserved)

ASIA Impairment ScaleY

Grade	Description	Classification
A	No motor or sensory function preserved in sacral segments S4-S5	Complete
B	Sensory function preserved, but motor function not preserved below neurological level including S4-S5	Incomplete
C	Motor function preserved below neurological level, and more than half of key muscles below neurological level have muscle grade < 3	Incomplete
D	Motor function preserved below neurological level, and at least half of key muscles below neurological level have muscle grade ≥ 3	Incomplete
E	Motor and sensory functions are normal	Normal

Types of Shock

Feature	Spinal Shock	Neurogenic Shock	Hypovolemic Shock
BP	Hypotension	Hypotension	Hypotension
Pulse	Bradycardia	Bradycardia	Tachycardia - compensatory mechanism
Reflexes	Absent	Variable/Independent	Variable/Independent
Motor	Flaccid paralysis	Variable/Independent	Variable/Independent
Time	~48-72 hours after SCI	~48-72 hours after SCI	Following excessive blood loss
Mechanism	Peripheral neurons become temporarily unresponsive to brain stimuli	Disruption of autonomic pathway leads to loss of sympathetic tone and decreased systemic vascular resistance	Decreased preload leads to decreased cardiac output

Complete injury

an injury with no spared motor or sensory function below the affected level • Classified as ASIA A

Incomplete injury

• an injury with some preserved motor or sensory function below the injury level
• Incomplete spinal cord injuries:
• anterior cord syndrome
• Brown-Sequard syndrome
• central cord syndrome
• posterior cord syndrome
• conus medullaris syndrome
• cauda equina syndrome

Incomplete Cord Syndromes

Central Cord Syndrome

• Most common incomplete cord injury
• Often in elderly with minor extension injury mechanisms
• Pathophysiology: Hands and upper extremities located “centrally” in corticospinal tract

Clinical Presentation:

• Weakness with hand dexterity impairment
• Hyperpathia
• Motor deficit worse in UE than LE (some preserved motor function)

Anterior Cord Syndrome

• Worst prognosis of incomplete SCI
• Causes: Direct compression (osseous) of anterior spinal cord or anterior spinal artery injury
• Key feature: Lower extremities affected more than upper extremities

Brown-Sequard Syndrome

• Excellent prognosis
• Cause: Complete cord hemitranssection, usually seen with penetrating trauma

Clinical Features:

• Ipsilateral deficit: LCTL motor function, DC: proprioception, vibratory sense
• Contralateral deficit: LST: pain, temperature

Other Incomplete Syndromes

• Posterior cord syndrome
• Conus medullaris syndrome
• Cauda equina syndrome

Special Conditions

Osteoporotic Vertebral Compression Fracture

• Commonest vertebral injury
• Etiology: Minor trauma in osteoporotic people
• Prevalence: Affects up to 50% of people over 80 years old
• Diagnosis: Lateral radiographs
• Initial treatment: Observation and pain management
• Kyphoplasty: Reserved for patients with recalcitrant symptoms after 4-6 weeks of nonoperative treatment

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Cauda Equina SyndromeZ

• Etiology: Severe compression of nerve roots in the thecal sac of lumbar spine, most commonly due to acute lumbar disc herniation
• Critical: Early diagnosis is essential

Clinical Features:

• Back pain (most common)
• Unilateral or bilateral leg pain (2nd most common)
• Saddle anesthesia (highly specific)
• Bladder dysfunction: Urinary retention → overflow incontinence
• Unilateral or bilateral sensory changes in legs
• Unilateral or bilateral motor weakness in legs

Diagnosis:

• Urgent MRI to confirm cause

Treatment:

• Prompt surgical decompression
• Should be performed within 24 hours, absolutely within 48 hours

Common Spinal Disorders

Degenerative Conditions

Cervical Spondylosis

• Pathophysiology: Natural aging and degenerative process of cervical motion segment
• Age of onset: Typically begins at age 40-50; 85% of patients >65 years
• Presentation: Can lead to cervical radiculopathy, cervical myelopathy, or axial neck pain
• Diagnosis: Plain radiographs of cervical spine
• Treatment: Observation, medical management, or surgical management depending on severity and chronicity of pain, presence of instability, or neurological deficits

Cervical MyelopathyZ

• Definition: Common form of neurologic impairment caused by compression of cervical spinal cord, most commonly due to degenerative cervical spondylosis
• Typical presentation: Older patients with symmetric numbness and tingling in extremities, hand clumsiness, and gait imbalance
• Treatment: Usually surgical decompression and stabilization as condition is associated with step-wise progression

Clinical Presentation:

• Neck pain and stiffness
• Extremity paresthesias: diffuse, bilateral, nondermatomal numbness and tingling
• Weakness and clumsiness: bilateral weakness and decreased manual dexterity (dropping objects, difficulty manipulating fine objects)
• Gait instability: Most important clinical predictor
• Urinary retention

Physical Examination:

• Upper motor neuron signs (spasticity):
  • Hyperreflexia
  • Hoffmann’s sign: Snapping patient’s distal phalanx of middle finger leads to spontaneous flexion of other fingers (most common physical exam finding)
  • Sustained clonus: > three beats defined as sustained clonus
  • Babinski test: Positive with extension of great toe

Imaging:

• MRI: Study of choice to evaluate degree of spinal cord and nerve root compression

Management:

• Observation
• Symptomatic treatment
• Surgery (decompression and fusion)

Cervical Radiculopathy

• Definition: Clinical condition characterized by unilateral arm pain, numbness and tingling in dermatomal distribution in hand, and weakness in specific muscle groups
• Evaluation: Thorough neurologic examination, cervical spine radiographs including flexion-extension views, and MRI of cervical spine
• Treatment: Nonoperative treatment successful in 75%-90% of patients; surgical decompression reserved for refractory cases or patients with progressive neurologic deficits

Imaging Examples:

Surgical Treatment - Anterior Cervical Discectomy and Fusion:

Lumbar Disc Herniation

• Significance: Very common cause of low back pain and unilateral leg pain (radiculopathy)
• Diagnosis: Made clinically and confirmed with MRI studies of lumbar spine
• Initial treatment: Nonoperative with oral medications and physical therapy for radicular leg pain
• Surgical indication: Microdiscectomy for severe pain and/or motor deficit that have failed to respond to nonoperative management

L5/S1 Disc Herniation Example:

Degenerative Spondylolisthesis

• Definition: Common degenerative condition characterized by subluxation of one vertebral body anterior to the adjacent inferior vertebral body with intact pars
• Demographics: Most common in females over 40 years of age, at the L4-5 level
• Diagnosis: Lateral radiographs; flexion and extension lateral lumbar radiographs can identify degree of instability
• MRI: Helpful for central or foraminal stenosis

Treatment:

• Nonoperative: Trial with NSAIDs and physical therapy
• Surgical: Indicated for progressive disabling pain that has failed nonoperative management, and/or progressive neurological deficits

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Scoliosis

Deformities

Scoliosis Classification

• Adolescent Idiopathic Scoliosis
• Infantile Idiopathic Scoliosis
• Congenital Scoliosis
• Neuromuscular Scoliosis: Irregular spinal curvature caused by disorders of brain, spinal cord, and muscular system

Adolescent Idiopathic Scoliosis

• Definition: Coronal plane spinal deformity most commonly presenting in adolescent girls from ages 10 to 18

History Assessment:

• Who noticed it? Family history?
• When was it noticed?
• Pre-natal, post-natal history?
• Pubertal status?
• Pain presence?
• Previous treatment?

Physical Examination:

• Leg length inequality
• Midline skin defects (hairy patches, dimples, nevi)
• Signs of spinal dysraphism
• Shoulder height differences
• Truncal shift
• Rib rotational deformity (rib prominence)
• Waist asymmetry and pelvic tilt
• Café-au-lait spots (neurofibromatosis)
• Foot deformities (cavovarus)

Adams Forward Bending Test:

- Normal spine - Scoliosis deformity

• Adams test

Imaging:

Severity Grades:

• Mild: 10-25°
• Moderate: 25-45°
• Severe: >45°

Treatment Based on Severity:

• Observation: Mild curves, depending on age and skeletal maturity
• Bracing: Moderate curves (25-45°) in growing patients

• Surgery: Severe curves (>45°) or progressive curves

Infantile Idiopathic Scoliosis

• Definition: Coronal plane spinal deformity presenting in children ages 3 years or less
• Characteristics: Usually normal kids with no other pathologies

Congenital Scoliosis

• Definition: Congenital spinal deformity occurring due to failure of normal vertebral development during 4th to 6th week of gestation
• Association: Usually patients have other congenital pathologies

Infections

Spinal Epidural Abscess

• Definition: Spinal infection caused by collection of pus or inflammatory granulation tissue between dura mater and surrounding adipose tissue
• Presentation: Pain (87% of cases), often severe and insidious in onset; Neurologic deficits present in ~33%
• Diagnosis: MRI studies with contrast
• Treatment: Prompt surgical decompression and long-term IV antibiotics

Risk Factors:

• IV drug abuse
• Immunodeficiency
• Malignancy
• HIV infection

Microbiology:

• Staphylococcus aureus is most common organism