Spinal Cord Injury Classification and Syndromes

Classifying the type and grading the severity of a traumatic or non-traumatic spinal cord injury is a universal language spine specialists speak that can improve patient communication.

Spine specialists who diagnose and treat traumatic spinal cord injuries (SCI) utilize a classification system to evaluate and grade a patient’s injury in terms of severity. Classification can be likened to a universal language all SCI specialists speak. The grading of an injury improves communication across different medical specialties.

Furthermore, classifying the type and severity of SCI can help patients better understand the extent of their functional and neurological injury and potential for improvement.
Diagram of spinal cord structuresAnatomical cross section of the human spinal cord. Photo Source: 123RF.com.

How Doctors Classify Spinal Cord Injury

Doctors all over the world classify SCI using a method developed by the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). If your doctor suspects an SCI, he or she may conduct the ISNCSCI exam shortly after you arrive in the hospital.

The ISNCSCI is based on 3 scores:

  1. American Spinal Injury Association (ASIA) motor score, which grades muscle strength and movement.
  2. The ASIA sensory score, which grades light touch and pinprick feeling.
  3. The ASIA Impairment Scale grade, which determines whether the injury is complete or incomplete.

More about the ASIA Impairment Scale
The ASIA Impairment Scale assigns the SCI a grade based on its severity. Grades range from A to E, with A being the most severe injury and E being the least severe.

Grade A
Complete sensory or motor function loss below the level of injury.

Grade B
Sensation is preserved below the level of injury, but motor function is lost.

Grade C
Motor function below the level of injury is preserved, with more than half of the main muscles receiving a less than 3 grade on the ASIA motor score.

Grade D
Motor function below the level of injury is preserved, with more than half of the main muscles receiving at least a 3 or greater grade on the ASIA motor score.

Grade E
Normal sensation and motor function.

Complete and Incomplete Spinal Cord Injuries
The ASIA Impairment Scale determines the category of SCI, which typically is complete or incomplete. A third, less common category—discomplete—refers to complete injuries that show some signs of brain-muscle connectivity.

  • Complete SCI occurs when there’s a total loss of function (motor) and feeling (sensory) below the injury level. For example, a thoracic injury may start at the torso and arms level, but it will also affect the low back, pelvis, groin, tailbone, legs, and toes. Complete SCI affects both sides of the body equally.
  • With incomplete SCI, some function and feeling remain below the injury level. Typically, one side of the body has more function or feeling than the other side. There are different types, or syndromes, of incomplete SCI, including central cord syndrome, Brown-Séquard syndrome, anterior cord syndrome, and posterior cord syndrome.

Spinal Cord Injury Syndromes

Central cord syndrome
Central cord syndrome is the most common incomplete SCI syndrome, occurring in 15-25% of traumatic SCIs. Central cord syndrome is common in elderly patients with a history of cervical spondylosis and spinal stenosis who suffer a SCI from a traumatic fall. As the name suggests, this syndrome affects the central part of the spinal cord. The central spinal cord contains large nerve fibers that exchange information between the spinal cord and the cerebral cortex. The cerebral cortex is important to personality, interpreting sensation (feeling), and motor function. The central spinal cord is important for hand and arm function, such as fine motor control (eg, writing), although the lower body may also be affected (eg, loss of bladder control).
Diagram of the Cerebral CortexThe cerebral cortex is made up of 4 different lobes; the frontal, parietal, temporal and occipital. Photo Source: 123RF.com.Brown-Séquard syndrome
Brown-Séquard syndrome most often occurs in patients who suffered a penetrating traumatic SCI, such as a bullet or knife wound. This syndrome affects either the left or right side of the spinal cord, but symptoms can affect both sides of the body. It is characterized by partial loss of function or impaired function, a vibrating sensation on the same side of the injury, and pain and temperature loss on the opposite side of the injury.

Anterior and posterior cord syndromes
The anterior spinal cord is the front section of the structure, and the posterior spinal cord is the back. These syndromes are most common in people with non-traumatic SCI as opposed to traumatic SCI. Anterior cord syndrome causes complete loss of movement, and pain and temperature loss, but it preserves light touch sensations. Posterior cord syndrome produces the opposite effect: It causes loss of light touch sensation, but it preserves movement, and pain and temperature sensation.

Early Classification Leads to the Right Treatment at the Right Time

The ability for spine doctors worldwide to uniformly classify spinal cord injury allows them quickly to understand the SCI’s severity, including the associated SCI syndromes. With traumatic injury—and certainly spinal cord injury—time plays a critical role in outcomes. Having a standard SCI classification system helps patients get the right treatment earlier.

Suggested Additional Reading
A special issue of the Global Spine Journal set forth guidelines for the Management of Degenerative Myelopathy and Acute Spinal Cord Injury, which is summarized on SpineUniverse in Summary of the Clinical Practice Guidelines for the Management of Degenerative Cervical Myelopathy and Traumatic Spinal Cord Injury.

Updated on: 08/01/19
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