SCI Traumatic: Part 1

Author(s): Marika Hess, MD

Originally published:12/01/2011

Last updated:09/18/2015

1. DISEASE/DISORDER:

Definition

Traumatic spinal cord injury (SCI) refers to a traumatic insult to the spinal cord that results in impaired motor, sensory and/or autonomic function below the injured spinal cord level. Injury to the cervical segments through the first thoracic segment results in impaired function in both the arms and the legs, referred to as tetraplegia, while injury to the thoracic, lumbar or sacral segments of the spinal cord causes paraplegia, characterized by impaired function in the legs but sparing of the arms.

Etiology

Motor vehicle accidents are the most common cause of SCI, followed followed by falls, acts of violence and sports injuries. Motor vehicle accidents are consistently the leading cause of SCI in the general population and rates have remained relatively steady. The proportion of injuries due to falls increases with advancing age, and falls are the leading cause of injury in persons older than 65 years of age.

Epidemiology including risk factors and primary prevention

In the United States (US), there are 12,500 new cases each year. Although traumatic SCI primarily affects young males between the ages of 15 and 35, the age at injury has been steadily increasing. The incidence peaks in young adulthood and declines thereafter, though there appears to be a secondary rise in incidence among the elderly. Falls are the leading cause of SCI among persons aged >60. The most common injury category is incomplete tetraplegia followed by incomplete paraplegia, complete paraplegia, and complete tetraplegia. Of all injuries, 34% are complete, 66% are incomplete. The proportion of incomplete injuries, high cervical injuries and ventilator dependence is increasing. In the US, violence is a more common cause of SCI than in most countries, but has declined steadily since the 1990’s. SCI due to sports injuries has also seen a decline, whereas injures due to falls have been increasing

Patho-anatomy/physiology

SCI can be characterized as follows:

  1. Primary insult is disruption of neural and vascular structures of the spinal cord at the time of initial trauma. Secondary injury refers to a cascade of events following the initial injury that cause further tissue damage. Possible mechanisms include inflammation, ischemia, increased vascular permeability, and release of free radicals and neuroexcitatory neurotransmitters. These events cause spinal cord swelling, cell death and neurological deterioration.
  2. SCI without radiological abnormalities (SCIWORA) refers to an acute SCI that occurs without evidence of vertebral fractures on plain radiographs or on computed tomography (CT) scans.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

  1. Onset of motor, sensory and autonomic dysfunction after SCI is usually sudden.
  2. Spinal shock occurs in the initial hours to days post injury with loss of reflexes and sensorimotor function below the level of injury.
  3. Motor and sensory recovery depend on the extent and location of the insult; persons with incomplete SCI recover faster and to a greater extent than do those with complete injuries.
  4. Regardless of level and completeness of injury, most recovery occurs within the first 6 months after injury.
  5. Acute SCI often results in a disruption of autonomic regulation of the bowel and bladder as well as reduction of cardiopulmonary reserve, characterized by a decline in blood pressure and lung volumes. Recovery can occur for several years after SCI, although rate of progression is slow and may not yield functional gains.
  6. SCI exacerbates the normal physical and physiological decline associated with aging; persons with SCI manifest medical, cognitive and functional problems associated with aging at an earlier age.

Specific secondary or associated conditions and complications

SCI is associated with complications involving every organ system.

Loss of lung volumes, impaired cough and difficulty clearing secretions predispose individuals with cervical and high thoracic injuries to respiratory impairment and lung infections. Ventilatory failure due to diaphragmatic paralysis occurs in people with high tetraplegia.

Impaired sensation, mobility, and nutritional status together with bowel and bladder incontinence, can result in skin breakdown and pressure ulcers.

Urinary tract infections are the most common source of infections in individuals with SCI and contribute to other conditions, such as urinary stones and bladder cancer.

Constipation, fecal impaction, and anorectal problems are common consequences of impaired bowel control.

Cardiovascular sequelae of SCI include low resting blood pressure, orthostatic hypotension, cardiac deconditioning and coronary artery disease.

Autonomic dysreflexia is a potentially life-threatening condition associated with SCI above the T6 level. It is characterized by an abrupt rise in blood pressure resulting from a noxious stimulus below the level of injury.

Autonomic impairment results in sexual dysfunction. Fertility rates are generally preserved in females and affected in males.

SCI can result in a variety of endocrine and metabolic conditions, including electrolyte disturbances, impaired lipid metabolism and osteoporosis. Body composition changes with loss of skeletal muscle and gain of adipose tissue, resulting in insulin resistance and lipid abnormalities.

Late neurological decline may result from development of post-traumatic syringomyelia or from development of compressive neuropathies.

Pain is common after SCI and can be neuropathic or nociceptive in origin. Overuse syndromes are common causes of musculoskeletal pain.

Incidence of depression and substance abuse is increased Late neurological decline can result from post-traumatic syringomyelia or compression and metabolic neuropathies.

2. ESSENTIALS OF ASSESSMENT

History

The mechanism of injury determines the extent of SCI and likelihood of other significant injuries. Details of the trauma, including mechanism, speed of impact and loss of consciousness, can be helpful.

Altered mental status, neurologic deficit and evidence of intoxication should be assessed.

Concomitant rheumatoid arthritis, atlanto-odontoid subluxation (common in Down’s syndrome), osteoarthritis, ankylosing spondylitis, osteoporosis and spinal stenosis predispose individuals to SCI.

Physical examination

The spine should be palpated for local tenderness. Tone and reflexes should be evaluated. A careful neurological examination must be performed according to the International Standards for Neurological Classification of SCI (ISNCSCI). The International Standards outline details of the neurological examination and classification. The level and completeness of SCI should be determined with a careful sensory examination for light touch and pin prick at key sensory points, and motor examination of designated key muscles bilaterally. The neurological completeness of SCI is classified according to the American Spinal Injury Association (ASIA) Impairment Scale.

The ASIA Impairment is used to predict neurological severity and predict recovery. Serial examinations track neurological progress. The classifications are as follows:

  1. A = Complete. No sensory or motor function is preserved in the sacral segments S4-S5.
  2. B = Sensory Incomplete. Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5, AND no motor function is preserved more than three levels below the motor level on either side of the body.
  3. C = Motor Incomplete. Motor function is preserved below the neurological level, and more than half of key muscle functions below the single neurological level of injury (NLI) have a muscle grade less than 3.
  4. D = Motor Incomplete. Motor function is preserved below the neurological level, and at least half the key muscle functions below the NLI have a muscle grade > 3.
  5. E = Normal.
  6. Autonomic function can be assessed by presence/ absence neurogenic shock, cardiac dysrhythmias, orthostatic hypotension, autonomic dysreflexia, temperature dysregulation and hyperhidrosis

Functional assessment

The Functional Independence Measure (FIM) ‑ common and reliable measure of level of independence and functioning.

Spinal Cord Independence Measure (SCIM) ‑ designed as an alternative to the FIM to assess 16 categories of functional independence.

The Walking Index for Spinal Cord Injury (WISCI) ‑ measures the patient’s ability to walk and describes the amount of assistance needed for walking.

The ISNCSCI using the ASIA Impairment Scale allows prediction of corresponding functional expectations depending on the patient’s age and other comorbidities.

Laboratory studies

Studies are performed to assess presence of medical conditions, such as bleeding, infections, electrolyte and acid-base disturbances

Imaging

Anterior-posterior (AP), lateral and open-mouth atlantoaxial radiographs should be ordered if any suspicion for SCI exists.

Flexion extension views can be ordered in alert patients without neurological abnormalities who have spine tenderness and normal routine x-rays

CT scans are superior to radiographs in detecting fractures and should be ordered if there is suspicion for spinal injury despite normal radiographs, or if radiographs are unable to visualize the spine adequately.

Magnetic resonance imaging (MRI) is excellent in detecting presence and extent of SCI and associated soft tissue injuries. It also has a role in establishing prognosis for recovery.

Supplemental assessment tools

Head CT scan should be performed if there is suspicion for head injury.

Intraoperative neurophysiological monitoring, including somatosensory and motor evoked potentials, can assist in identifying evolving spinal cord injury during spine surgery.

Electromyography (EMG) and nerve conduction studies can be performed to evaluate presence of associated plexopathies and nerve root lesionsNeuropsychological testing should be considered of there is suspicion for traumatic brain injury.

Early predictions of outcomes

Motor function is the primary determinant of overall function.

  1. While 10% of complete injuries convert to incomplete, motor recovery is often limited and does not translate into functional ambulation
  2. Incomplete injuries have a better prognosis than complete injuries and recover faster.. Approximately 50% of patients classified with ASIA B and 75% classified with ASIA C become ambulatory
  3. Lower extremity motor score can help predict ambulation potential
  4. Intramedullary hemorrhage and edema on MRI portend poorer recovery and function

Environmental

Environmental modifications, the use of assistive equipment and technology and acquisition of personal attendants are ways to support individuals with SCI. Home and work modifications such as providing ramps, widening doors, lowering workspaces and removing rugs facilitate wheelchair access and independence. Environmental control devices allow persons with high injuries to access their environment independently.

Social role and social support system

Persons with a strong support system are more likely to adapt well to their injury.

Level and completeness of SCI do not correlate with subjective sense of well being.

Divorce rates are higher after SCI.

Persons with SCI can assume fulfilling relationships and parental roles.

Professional Issues

Improper radiographic interpretation or incomplete imaging can result in failure to identify spinal fractures and instability.

Patients with one spinal fracture may have secondary fractures that can be missed. Failure to identify these may result in neurological deterioration.

Absence of spinal fractures does not exclude SCI; a detailed neurological examination is required.

3. REHABILITATION MANAGEMENT AND TREATMENTS

4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

Gaps in the evidence-based knowledge

Not applicable

REFERENCES

Bibliography

American Spinal Injury Association. International Standards for Neurological and Functional Classification of Spinal Cord Injury–Revised2011.Atlanta, GA: ASIA. 2011.

Burns AS, Ditunno JF. Establishing prognosis and maximizing functional outcomes after spinal cord injury: a review of current and future directions in rehabilitation management. Spine. 2001;26(24)(suppl):S137-S145.

Consortium for Spinal Cord Medicine. Outcomes following traumatic spinal cord injury: clinical practice guidelines for health-care professionals. Chicago, IL: Paralyzed Veterans of America. 1999.

Devivo MJ, Chen Y. Trends in new injuries, prevalent cases and aging with spinal cord injury. 2011; 92(3):332-8.

DeVivo MJ, Kartus PL, Rutt RD, et al. The influence of age at time of spinal cord injury on rehabilitation outcome. Arch Neurol. 1990;47(6):687-91.

Domeier RM, Evans RW, Swor RA, et al. Prehospital clinical findings associated with spinal injury. Prehosp Emerg Care. 1997; Jan-Mar(1):11-15.

Marino RJ, Burns S, Graves DE. Upper-and lower- extremity motor recovery after traumatic cervical spinal cord injury: an update from the National Spinal Cord Injury Database. Arch Phys Med Rehabil. 2011; 92: 368-75.

Spinal cord injury facts and figures at a glance. National Spinal Cord Injury Statistical Center. J Spinal Cord Med 2010; 33 (4):439-40.

Original Version of the Topic

Marika Hess, MD. SCI Traumatic: Part 1. 12/01/2011

Author Disclosure

Marika Hess, MD
Nothing to Disclose

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