What Is Spinal Cord Injury (SCI)?

Spinal cord injury (SCI) is an injury of the spinal cord. SCI can be traumatic such as resulting from a motor vehicle accident, fall, sports injury, acts of violence, and surgical complications. It can also be non-traumatic such as resulting from a tumor or diseases .

The spinal cord is located in the spinal canal of the spine. The spine reaches from the nape of the neck to the sacral bone and forms the framework of our body. It consists of 33 single overlapping bones, the vertebrae. These are held together by disks, tendons and ligaments. The spine can be divided into five sections:

  • cervical spine (cervical, abbr. C)
  • thoracic spine (thoracic, abbr. T)
  • lumbar spine (lumbar, abbr. L)
  • sacral spine (sacral, abbr. S)
  • coccyx (tailbone)

The spinal cord, in principle, is a cord of nerves, and can be compared with a telephone cable that transports signals back and forth between the brain and the body. The spinal cord can be divided into four sections, which can be further subdivided into individual segments (neurotoms). In between the vertebrae, the nerves of the spinal cord branch off on each side to the respective body regions. There are

  • 8 cervical segments (C1 to C8)
  • 12 thoracic segments (T1 to T12)
  • 5 lumbar segments (L1 to L5)
  • 5 sacral segments (S1 to S5)

In case of a SCI, the spinal cord is damaged or even severed at a specific spot due to an accident or a health condition, resulting in a disruption of communication between the body parts below the damage and the brain. The damage of the spinal cord is called lesion. Important functions such as mobility (motor functions) or sensation (sensory functions) fail below the lesion.

Literature

  • Chin LS, Mesfin FB, Dawodu ST. Spinal cord injuries: Practice essentials, background, anatomy,  pathophysiology, etiology, epidemiology, prognosis, patient education. [Internet] 10 August 2017. Available from: http://www.emedicine.com/pmr/topic182.htm. Accessed March 2018.
  • Swiss Paraplegic Research. Community. [Wiki/Body & complications]. Spinal cord injury - What does this mean?  Basic knowledge about the injured body. [Internet] March 2018. Available from: https://community.paraplegie.ch/. Accessed March 2018.
  • Shepherd Center. Understanding spinal cord injury: What you should know about spinal cord injury and recovery. 2018. [Internet]  Available from: http://www.spinalinjury101.org/details/levels-of-injury. Accessed March 2018.

What Is the Difference Between Paraplegia and Tetraplegia?

Paraplegia is a paralysis starting in the thoracic (T1-T12), lumbar (L1-L5) or sacral (S1-S5) area, while tetraplegia is caused by damage in the cervical area (C1-C8). Persons with paraplegia possess good functioning of the arms and hands. The lesion occurs primarily in the trunk and legs. In comparison persons with tetraplegia additionally experience paralysis of the hands and partially of the arms.

In an initial clinical examination, the physician can locate the injury using x-rays or computer tomography (CT). While this technology makes the damage to the vertebrae visible, magnetic resonance imaging (MRI) can show the damage to the spinal marrow. The lesion height is defined by the last fully functioning segment of the spinal marrow. Tetraplegia "sub C6", for example, means that the marrow segments C1 to C6 are fully functioning whereas the segment C7 and below are affected.

Literature

  • Chin LS, Mesfin FB, Dawodu ST. Spinal cord injuries: Practice essentials, background, anatomy,  pathophysiology, etiology, epidemiology, prognosis, patient education. [Internet] 10 August 2017. Available from: http://www.emedicine.com/pmr/topic182.htm. Accessed March 2018.
  • Swiss Paraplegic Research. Community. [Wiki/Body & complications]. Spinal cord injury - What does this mean?  Basic knowledge about the injured body. [Internet] March 2018. Available from: https://community.paraplegie.ch/. Accessed March 2018.
  • Shepherd Center. Understanding spinal cord injury: What you should know about spinal cord injury and recovery. 2018. [Internet]  Available from: http://www.spinalinjury101.org/details/levels-of-injury. Accessed March 2018.

What Does “Complete” and “Incomplete” Mean?

Depending on the damage to the spinal cord nerves, the result is considered a complete or an incomplete lesion. Paraplegia is considered complete if no motor or sensory functions can be clinically determined below the lesion caused by the damage. As long as sensory and/or motor functions are detectable, the lesion is considered incomplete.

Neurological examinations enable the physician to locate the damage and determine its extent. The physician uses two international scales for this purpose  – the American Spinal Injury Association Impairment Scale (AIS), often referred to as ASIA scale, and the "Scale for the Autonomic Nervous System". The use of these scales are dependent on an exact assessment of the injury, the person's sustained sensory and motor functions, the injury level and the degree of lesion  – all of which help to forecast the possible impact on the person's daily living.

Literature

  • Chin LS, Mesfin FB, Dawodu ST. Spinal cord injuries: Practice essentials, background, anatomy,  pathophysiology, etiology, epidemiology, prognosis, patient education. [Internet] 10 August 2017. Available from: http://www.emedicine.com/pmr/topic182.htm. Accessed March 2018.
  • Swiss Paraplegic Research. Community. [Wiki/Body & complications]. Spinal cord injury - What does this mean?  Basic knowledge about the injured body. [Internet] March 2018. Available from: https://community.paraplegie.ch/. Accessed March 2018.
  • Shepherd Center. Understanding spinal cord injury: What you should know about spinal cord injury and recovery. 2018. [Internet]  Available from: http://www.spinalinjury101.org/details/levels-of-injury. Accessed March 2018.

What Are the Most Prevalent Consequences of Spinal Cord Injury?

When it comes to paralysis, people generally think about the inability to move the legs and/or hands. However, the consequences of damage to the spinal cord can go beyond the impact on mobility. This can be seen as impacting on three levels:

  • the motor level  – mobility is decreased
  • the sensory level  –  for example, sensitivity of the skin is decreased
  • and the autonomic level  – the activity and functions of the inner organs (bladder, bowel, cardiovascular activities, respiration, etc.) or sexual functions are controlled involuntarily, meaning that the person does not consciously control these functions.

If autonomic functioning of the bladder and bowel is impaired, the person affected would have to learn to manage these functions consciously. Optimal bladder and bowel management is important to avoid complications such as recurring bladder or kidney infection, or in the worse case, permanent damage.

Until 60 years ago, the life expectancy of persons with SCI was low due to such complications and for which no long-lasting treatment options were available. Thanks to the development of effective bladder and bowel management strategies including trained professional care, technological and medical aids, the life expectancy of persons with SCI has increased to almost the same level as persons without SCI. Bladder and bowel management is also an issue addressed early on in the treatment of SCI.

Another major issue confronting persons with SCI is recurring pressure sores. Specific attention should be paid to the sensitivity of the skin, since this is decreased in persons with SCI. Furthermore, persons with SCI frequently experience respiratory difficulties, and body temperature regulation in tetraplegics and paraplegics with high lesion levels is affected.

Despite the range of complications and difficulties that a person with SCI can experience, these can be addressed in a concerted effort by the person with SCI, his/her family or caregiver and, if engaged in a rehabilitation program, the rehabilitation team.

Literature

  • Chin LS, Mesfin FB, Dawodu ST. Spinal cord injuries: Practice essentials, background, anatomy,  pathophysiology, etiology, epidemiology, prognosis, patient education. [Internet] 10 August 2017. Available from: http://www.emedicine.com/pmr/topic182.htm. Accessed March 2018.
  • Swiss Paraplegic Research. Community. [Wiki/Body & complications]. Spinal cord injury - What does this mean?  Basic knowledge about the injured body. [Internet] March 2018. Available from: https://community.paraplegie.ch/. Accessed March 2018.
  • Shepherd Center. Understanding spinal cord injury: What you should know about spinal cord injury and recovery. 2018. [Internet]  Available from: http://www.spinalinjury101.org/details/levels-of-injury. Accessed March 2018.

American Spinal Injury Association (ASIA) Impairment Scale

American Spinal Injury Association (ASIA) impairment scale

The American Spinal Injury Association (ASIA) impairment scale or AIS describes a person's functional impairment as a result of a SCI. This scale indicates how much sensation a person feels after light touch and a pin prick at multiple points on the body and tests key motions on both sides of the body.

LT = light touch; PP = pin prick; DAP = deep anal pressure; AIS = ASIA Impairment Scale; NLI = neurologcal level of injury

  • Grade A = Complete. No sensory or motor function is preserved in the sacral segments S4-5.
  • Grade B = Sensory Incomplete. Sensory but no motor function is preserved below the neurological level and includes the sacral segments S4-5 (LT or PP at S4-5 or DAP), and no motor function is preserved more than three levels below the motor level on either side of the body.
  • Grade 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 (sensory function preserved at the most caudal sacral segments (S4-S5) by LT, PP or DAP), and has some sparing of motor function more than three levels below the ipsilateral motor level on either side of the body. (This includes key or non-key muscle functions to determine motor incomplete status.) For AIS C  – less than half of key muscle functions below the single NLI have a muscle grade ≥ 3.
  • Grade D = Motor Incomplete. Motor incomplete status as defined above, with at least half (half or more) of key muscle functions below the single NLI having a muscle grade ≥ 3.
  • Grade E = Normal. If sensation and motor function as tested with the ISNCSCI are graded as normal in all segments, and the patient had prior deficits, then the AIS grade is E. Someone without an initial SCI does not receive an AIS grade.
Muscle Function Grading
0 Total paralysis
1 Palpable or visible contraction
2 Active movement, full range of motion (ROM) with gravity eliminated
3 Active movement, full ROM against gravity
4 Active movement, full ROM against gravity and moderate resistance in a muscle specific position
5 (normal) Active movement, full ROM against gravity and full resistance in a functional muscle position expected from an otherwise unimpaired person
5* (normal) Active movement, full ROM against gravity and sufficient resistance to be considered normal if identified inhibiting factors (i.e. pain, disuse) were not present
NT Not testable (i.e. due to immobilization, severe pain such that the person cannot be graded, amputation of limb, or contracture of > 50% of the normal range of motion)
Sensory Grading
0 Absent
1 Altered, either decreased/impaired sensation or hypersensitivity
2 Normal
NT Not testable

Literature