Spinal Cord Injury (SCI) Basics

Spinal Cord Injury (SCI) Basics

• SCI is defined as injury or trauma to the spinal cord
• The most frequently involved areas include:
  • 5th, 6th, and 7th cervical vertebrae (C5 to C7)
  • 12th thoracic vertebra (T12)
  • First lumbar vertebra
• Young adult males are primarily affected by SCI
• SCI is considered a major health disorder
• Potential results of SCI include paraplegia and tetraplegia

Mechanisms of Injury

• Spinal cord injuries can involve:
  • Contusion
  • Laceration
  • Compression

Causes of Spinal Cord Injury

• Traumatic causes include:
  • Motor vehicle accidents
  • Falls
  • Work-related accidents
  • Sports injuries
  • Penetrations
• Non-traumatic causes include:
  • Cancer
  • Infection
  • Intervertebral disc disease
  • Vertebral injury
  • Spinal cord vascular disease

Pathophysiology

• Traumatic and non-traumatic causes lead to:
  • Nerve fiber swelling
  • Decreased circulation to the spinal cord
  • Ischemia
  • Necrosis
  • Destruction of the spinal cord

Categories of SCI

• Primary injuries:
  • Involve the initial insult or trauma
• Secondary injuries:
  • A result of a contusion or tear injury

Segmental Spinal Cord Levels and Function

• C1-C6: Control neck flexors
• C1-T1: Control neck extensors
• C3, C4, C5: Supply the diaphragm, primarily C4
• C5, C6: Facilitate shoulder movement, arm elevation, elbow flexion; C6 externally rotates the arm
• C6, C7: Extend elbow and wrist (triceps and wrist extensors) and pronate the wrist
• C7, T1: Flex the wrist and supply small muscles of the hand
• T1-T6: Innervate intercostals and trunk above the waist
• T7-L1: Control abdominal muscles
• L1, L2, L3, L4: Enable thigh flexion
• L2, L3, L4: Enable thigh adduction
• L4, L5, S1: Enable thigh abduction
• L5, S1, S2: Enable extension of the leg at the hip
• L2, L3, L4: Enable extension of the leg at the knee
• L4, L5, S1, S2: Enable flexion of the leg at the knee
• L4, L5, S1: Enable dorsiflexion of foot and extension of toes
• L5, S1, S2: Enable plantar flexion and flexion of toes

Clinical Manifestations and Types of Injury

• Incomplete Spinal Cord Lesions:
  • Sensory or motor fibers (or both) are preserved below the lesion
• Complete Spinal Cord Lesion:
  • Total loss of sensation and voluntary muscle control below the lesion
  • May result in paraplegia or tetraplegia

Neurologic Level

• This refers to the lowest level at which sensory and motor functions are normal
• Below the neurologic level:
  • Total sensory and motor paralysis occurs
  • Loss of bowel and bladder control
  • Loss of sweating and vasomotor tone
  • Marked reduction of blood pressure can occur from loss of peripheral vascular resistance

Location of Injury

• Specific effects of SCI depend on the location of the injury
• Determining the exact "level" of injury is critical for:
  • Making accurate predictions about the specific parts of the body that may be affected by paralysis and loss of function

Cervical Injuries

• C-1/C-2: Often result in loss of breathing
• C3, C4, C5: Result in loss of diaphragm function
• C4: Results in significant loss of function at the biceps and shoulders
• C5: Results in potential loss of function at the shoulders and biceps and complete loss of function at the wrists and hands
• C6: Results in limited wrist control and complete loss of hand function
• C7 & T1: Result in lack of dexterity in the hands and fingers
• Complete injuries above C7:
  • Individuals typically cannot handle activities of daily living and function independently
  • Reduced ability to regulate heart rate, blood pressure, sweating, and body temperature

Thoracic SCI

• Complete injuries at or below the thoracic spinal levels result in paraplegia
• Functions of the hands, arms, neck, and breathing are usually not affected.
• T1 to T8 injuries result in the inability to control the abdominal muscles
• T9 to T12 injuries result in partial loss of trunk and abdominal muscle control

Lumbosacral SCI

• Injury to lumbar or sacral areas results in decreased control of the legs and hips, urinary system, and anus
• Injury to the sacral spinal region can cause dysfunction of the bowel and bladder and affect sexual function.

Effects of Spinal Cord Injuries

• Central Cord Syndrome:
  • Lesion in the central portion of the spinal cord
• Inverse paraplegia:
  • Potential causes include ischemia, hemorrhage, edema or necrosis; hyperextension injuries
• Anterior Cord Syndrome
  • Associated with flexion type injuries to the cervical spine
  • Motor function, pain sensation, and temperature sensation are lost below the level of injury
  • Touch, proprioception, and the sense of vibration remain intact
• Posterior Cord Syndrome
  • Damage to the posterior portion of the spinal cord and/or interruption to the posterior spinal artery
  • Causes the loss of proprioception below the level of injury
  • Motor function, the sense of pain, and sensitivity to light touch remain intact
• Brown-Sequard Syndrome
  • Results from penetrating injuries that cause hemisection of the spinal cord
  • Ipsilateral paralysis/paresis occurs with a loss of touch, pressure, and vibration
  • Contralateral loss of pain and temperature sensation
  • Typically, the cause is a knife or missile injury or an acute ruptured disk
• Conus medullaris syndrome:
  • Associated with injury to the sacral cord and lumbar nerve roots
• Cauda equina syndrome:
  • Due to injury to the lumbosacral nerve roots in the spinal canal

ASIA Impairment Scale (SCI Classification)

• A = "Complete"
• B = "Incomplete"
• C = "Incomplete"
• D = "Incomplete"
• E = "Normal"

Diagnostics

• Detailed neurologic exam
• X-rays
• CT scan
• MRI
• If contraindicated, Myelogram may be used to visualize the spinal axis
• ECG

Emergency Management

• Proper handling of the patient is crucial
• Assume SCI is present if there is direct trauma to the head & neck until ruled out
• Initial care includes:
  • Rapid assessment
  • Immobilization & extrication
  • Stabilization or control of life-threatening injuries
  • Transportation to the most appropriate medical facility

At the Scene of Injury

• Immobilize the patient on a spinal board with the head and neck in a neutral position
• Control the patient’s head to prevent flexion, rotation, and extension
• Any twisting movement may irreversibly damage the spinal cord

Medical Management (Acute Phase)

• Goals
  • Prevent secondary injury
  • Observe symptoms of progressive neurologic deficits
  • Prevent complications
• Resuscitation
• Pharmacologic therapy
  • High-dose IV corticosteroids
  • Methylprednisolone sodium succinate
• Respiratory therapy: O2 is administered
• Skeletal Fracture Reduction & Traction: Cervical fractures are reduced & the cervical spine is aligned.
• Cast

Surgical Management

• Surgery may be necessary if:
  • Compression of the cord is evident
  • The injury results in a fragmented or unstable vertebral body
  • The injury involves a wound that penetrates the cord
  • Bony fragments are in the spinal canal
  • The patient’s neurologic status is deteriorating

Complications of SCI

• Pressure ulcers and infection
• Deep vein thrombosis
• Respiratory failure
• Pneumonia
• Neurogenic bladder

Neurogenic Shock

• This involves loss of ANS function below the level of the lesion
• Vital organs are affected
• Decreased BP, HR & CO
• Leads to venous pooling in the extremities & peripheral vasodilation
• Results in Neurogenic Shock

Autonomic Dysreflexia

• It is an uninhibited & exaggerated reflex of the ANS to stimulation
• Occurs with cord lesions above T6
• Factors that trigger are often related to the stimulation of the bladder, bowel & skin
• Assessment findings include:
  • Pounding headache
  • Profuse sweating
  • Nasal congestion
  • Piloerection
  • Bradycardia
  • Severe hypertension

Emergency Care for Autonomic Dysreflexia

• Indicated once the symptoms manifest
• Efforts are made to lower the blood pressure

Whiplash Injury

• Caused by violent hyperextension & flexion of the neck
  • Results in damage to muscles, disks, ligaments & nervous tissues of cervical spine
  • Assessment: weakness, dizziness, gait disturbance, nausea and vomiting, occipital headache, nuchal rigidity
  • Management: bed rest, analgesic, hot packs to the neck, cervical collar

Rehabilitation

• Begins in the acute care setting
• Involves physical therapists, occupational therapists, social workers, psychologists & other health care professionals
• In the acute phase, physical therapists focus on:
  • The patient’s respiratory status
  • Prevention of indirect complications
  • Maintaining the range of motion
  • Keeping available musculature active