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 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 approximately 18,000 new cases each year. Although traumatic SCI historically primarily affects young males between the ages of 15 and 35, the average age at injury has been steadily increasing. The most common injury category is incomplete tetraplegia followed by similar rates of incomplete and complete paraplegia, with complete tetraplegia the least common. Of all injuries, ~30% are complete and ~70% are incomplete, and about 60% are tetraplegia. 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. SCI due to sports injuries has been declining, whereas injuries due to falls have been increasing.1
Patho-anatomy/physiology
SCI can be characterized as follows:
- 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.
- 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)
- Onset of motor, sensory and autonomic dysfunction after traumatic SCI is usually sudden.
- Spinal shock occurs in the initial hours post injury and may last days to weeks. It is defined as the loss of reflexes below the level of injury.
- 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. Patients with a higher impairment score (indicating a less severe injury) experience greater and faster rates of motor recovery.
- Regardless of level and completeness of injury, most recovery occurs within the first 6 months after injury. Additional recovery, however, can occur up to 18 months after SCI although rate of progression is slow and may not yield functional gains.
- 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.
- 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.
Inspiratory muscle weakness results in loss of lung volumes and expiratory muscle weakness results in impaired cough, difficulty clearing secretions, and mucous plugging. Individuals with cervical and high thoracic injuries are more likely to have respiratory impairment and lung infections. Ventilatory failure due to diaphragmatic impairment may occur in people with high tetraplegia.
Impaired sensation, mobility, and nutritional status, along with increased moisture due to bowel and bladder incontinence, can result in pressure injury, skin breakdown, and infection.
Autonomic impairment results in loss of bowel and bladder control, impaired thermal and cardiovascular regulation, and sexual dysfunction. Fertility rates are generally preserved in females after an acute period of amenorrhea. Males with SCI may have lower sperm count and poor motility. Cardiovascular complications include low resting blood pressure, orthostatic hypotension, coronary artery disease, and reduced cardiovascular fitness. Individuals with spinal cord injury above T6, particularly those with complete injuries, are predisposed to developing autonomic dysreflexia, which is defined as an abrupt rise in blood pressure due to a noxious stimulus below the level of injury.
SCI can result in a variety of endocrine and metabolic conditions, including electrolyte disturbances (e.g., hyponatremia), impaired lipid metabolism, metabolic syndrome, and osteoporosis. Body composition changes including loss of skeletal muscle and increased adipose tissue can result in insulin resistance and dyslipidemia.
Urinary tract infections are the most common source of infections in individuals with SCI and a leading cause of hospitalization. Individuals with SCI are also at higher risk of pneumonia and sepsis, which are leading causes of mortality.2
Constipation, incontinence, and hemorrhoids are common consequences of impaired bowel control. Genitourinary complications include renal or bladder stones and higher rates of bladder cancer in those who catheterize.3
Late neurological decline may result from multiple causes, including central causes such as post-traumatic syringomyelia or new stenosis and compression due to spondylosis, as well as peripheral causes, such as peripheral neuropathy or a focal compressive mononeuropathy (e.g. carpal tunnel syndrome).
Pain is common after SCI and can be neuropathic or nociceptive in origin. Overuse syndromes are common causes of musculoskeletal pain; shoulder pain is common in both tetraplegia and paraplegia.
Incidence of depression is significantly increased in persons with SCI; the most common risk factor is depression prior to injury.4 There are also higher rates of anxiety and post-traumatic stress disorder, particularly acutely. Alcohol and substance use disorders are also more common in individuals with SCI.5
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.
Concomitant rheumatoid arthritis, atlanto-odontoid subluxation (e.g., as seen in Down’s syndrome), osteoarthritis, ankylosing spondylitis, and spinal stenosis predispose individuals to SCI.
Physical examination
The spine should be palpated for focal 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 Scale (AIS) is used to describe neurological severity and predict recovery. Serial examinations track neurological progress. The classifications are as follows:
- A = Complete. No sensory or motor function is preserved in the sacral segments S4-S5.
- 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.
- C = Motor Incomplete. Motor function is preserved at the most caudal sacral segments for voluntary anal contraction OR the patient meets the criteria for sensory incomplete status and has some sparing of motor function more than three levels below the ipsilateral motor level on either side of the body. Non-key muscles can be used for this designation. Less than half of key muscle functions below the single neurological level of injury have a muscle grade >/ 3.
- D = Motor function is preserved in at least half of key muscle functions below the single neurological level of injury with a muscle grade >/ 3 .
- E = Normal sensation and motor function in person with prior deficits
- Autonomic function can be assessed by presence/ absence of neurogenic shock, cardiac dysrhythmias, orthostatic hypotension, autonomic dysreflexia, temperature dysregulation and hyperhidrosis
Functional assessment
The ISNCSCI using the ASIA Impairment Scale allows prediction of corresponding functional expectations depending on the patient’s age and other comorbidities.
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 Spinal Cord Injury–Functional Index (SCI-FI) has been developed in the last decade to evaluate functional status of persons with SCI using Assistive Technology for basic mobility, self-care, fine motor function, and ambulation.6
Laboratory studies
Studies are performed to assess presence of medical conditions, such as bleeding, infections, electrolyte and acid-base disturbances
Imaging
CT is the preferred imaging modality for evaluation of bony spinal trauma. CT scans are superior to radiographs in detecting bone 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.7
Currently, the American College of Radiography recommends restricting use of plain radiographs to when there is a low suspicion of SCI or where CT is not possible.8 Flexion extension views can be ordered in alert patients without neurological abnormalities who have spine tenderness and normal routine x-rays or CT scan. Patients who have sustained spinal trauma or who have any neurologic deficits should undergo CT scans and/or magnetic resonance imaging (MRI).
Magnetic resonance imaging (MRI) is excellent in detecting presence and extent of SCI and associated soft tissue injuries. CT scans do not visualize ligaments, discs, the spinal cord, or peripheral nerve roots, so MRI must be used to assess for injuries to these structures. MRI also has a role in establishing prognosis for recovery from SCI.
Perfusion MRI and intraoperative contrast-enhanced ultrasonography are promising new modalities that may prove to be useful adjuncts to current imaging standards.7
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 lesions. Neuropsychological testing should be considered of there is suspicion for traumatic brain injury.
Early predictions of outcomes
The most important determinant of long-term prognosis is the neurologic completeness of the SCI based on the sacral sparing definition (presence of sensory and/or motor function at the lowest sacral level ie. sensory function in dermatomes S4-5, presence of deep anal pressure, or voluntary anal contraction).9
There have been conflicting study results as to whether timing of surgical decompression and stabilization affects neurological recovery. However, early decompression is typically pursued as some studies have suggested positive results for prognosis. This remains a knowledge gap in management of acute SCI.9
Motor function is the primary determinant of overall function.
- While ~20% of complete injuries convert to incomplete, motor recovery is often limited and does not translate into functional community ambulation
- Incomplete injuries have a better prognosis than complete injuries and recover faster. Approximately 30-50% of patients classified with AIS B and 65-75% classified with AIS C become ambulatory
- Lower extremity motor score can help predict ambulation potential
- Initial strength of a muscle below the level of injury at one month is predictive of muscle recovery at one year. Muscles with at least 1/5 strength are likely to have at least antigravity strength at one year.
- 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, adjustable height workspaces, and removing rugs facilitate wheelchair access and independence. Environmental control devices allow persons with high injuries to access their environment independently. Problems with transportation, inaccessibility of the natural and built environment, and pain have been identified as significant barriers to social and community participation.10
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.
Rehabilitation Management and Treatments
Cutting Edge/Emerging and Unique Concepts and Practice
Gaps in the Evidence-Based Knowledge
References
- National Spinal Cord Injury Statistical Center, Traumatic Spinal Cord Injury Facts and Figures at a Glance. Birmingham, AL: University of Alabama at Birmingham, 2022.
- van den Berg ME, Castellote JM, de Pedro-Cuesta J, Mahillo-Fernandez I. Survival after spinal cord injury: a systematic review. J Neurotrauma. 2010 Aug;27(8):1517-28. doi: 10.1089/neu.2009.1138. PMID: 20486810.
- Nahm LS, Chen Y, DeVivo MJ, Lloyd LK. Bladder cancer mortality after spinal cord injury over 4 decades. J Urol. 2015 Jun;193(6):1923-8. doi: 10.1016/j.juro.2015.01.070. Epub 2015 Jan 20. PMID: 25615534.
- Bombardier CH, Adams LM, Fann JR, Hoffman JM. Depression Trajectories During the First Year After Spinal Cord Injury. Arch Phys Med Rehabil. 2016 Feb;97(2):196-203. doi: 10.1016/j.apmr.2015.10.083. Epub 2015 Oct 23. PMID: 26525525; PMCID: PMC4746101.
- Budd MA, Gater DR Jr, Channell I. Psychosocial Consequences of Spinal Cord Injury: A Narrative Review. J Pers Med. 2022 Jul 20;12(7):1178. doi: 10.3390/jpm12071178. PMID: 35887675; PMCID: PMC9320050.
- Slavin, M. D., Ni, P., Tulsky, D. S., Kisala, P. A., Heinemann, A. W., Charlifue, S., Fyffe, D. C., Graves, D. E., Marino, R. J., Morse, L. R., Rosenblum, D., Tate, D., Worobey, L. A., Dawson, M. B., & Jette, A. M. (2016). Spinal Cord Injury–Functional Index/Assistive Technology Short Forms. Archives of Physical Medicine and Rehabilitation, 97(10), 1745-1752.e7. https://doi.org/10.1016/J.APMR.2016.03.029
- Shabani, S., Meyer, B. P., Budde, M. D., & Wang, M. C. (2021). Diagnostic Imaging in Spinal Cord Injury. https://doi.org/10.1016/j.nec.2021.03.004
- Daffner, R. H., & Hackney, D. B. (2007). ACR Appropriateness Criteria® on Suspected Spine Trauma. Journal of the American College of Radiology, 4(11), 762–775. https://doi.org/10.1016/J.JACR.2007.08.006
- Chay, W., & Kirshblum, S. (2020). Predicting Outcomes After Spinal Cord Injury. Phys Med Rehabil Clin N Am, 31, 331–343. https://doi.org/10.1016/j.pmr.2020.03.003
- Barclay, L., McDonald, R., & Lentin, P. (2015). Social and community participation following spinal cord injury: a critical review. International Journal of Rehabilitation Research. Internationale Zeitschrift Fur Rehabilitationsforschung. Revue Internationale de Recherches de Readaptation, 38(1), 1–19. https://doi.org/10.1097/MRR.0000000000000085
Bibliography
American Spinal Injury Association. International Standards for Neurological Classification of Spinal Cord Injury—Revised 2019.Honolulu, HI 2019.
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.
Original Version of the Topic
Marika Hess, MD. SCI Traumatic: Part 1. 12/01/2011
Previous Revision(s) of the Topic
Marika Hess, MD. SCI Traumatic: Part 1. 9/18/2015
Marika Hess, MD. SCI Traumatic Part One: Disease/Disorder and Essentials of Assessment. 5/2/2020
Author Disclosure
Kate Delaney, MD
Nothing to Disclose
Aubree Fairfull, MD
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