Spinal Cord Injury Causes and Risk Factors

SCI Causes and Risk Factors

SCI Causes

About 200,000 people live with spinal cord injuries in the United States. The leading SCI causes are forms of trauma. A spinal cord injury may result from direct injury to the cord itself or indirectly from damage to surrounding bones, tissues, or blood vessels. The following are the most common SCI causes in the United States:

  • Motor vehicle accidents are the leading SCI causes for people under age 65, accounting for almost 50 percent of new spinal cord injuries each year.
  • Falls make up approximately 22 percent of spinal cord injuries and are the leading SCI causes for people 65 years and older.
  • Acts of violence account for 15 percent of spinal cord injuries and include such things as gunshot and knife wounds.
  • Sports and recreation account for approximately 8 percent of spinal cord injuries.

SCI Risk Factors

Every year, approximately 11,000 new spinal cord injuries are documented. Although a spinal cord injury is often caused by an unexpected accident that can happen to anyone at any age, some groups of people are more likely to suffer a spinal cord injury. These include:

  • Men: Men are more likely than women to sustain a spinal cord injury. Over 80 percent of all spinal cord injuries are sustained by men.
  • Young adults: People are at a higher risk of sustaining a spinal cord injury between the ages of 16 and 30. Motor vehicle accidents are the leading SCI causes for young adults.
  • Seniors: Spinal cord injuries suffered by people over 65 years-old are most oftentimes caused by a fall. Falls account for a large number of spinal cord injuries in older people.
  • Athletes: Sport-related injuries account for 8 percent of spinal cord injuries each year. High impact sports such as wrestling, football, rugby, and gymnastics result in a higher risk of spinal cord injury.

SCI Sources:

Spinal Cord Injury Causes: The Mayo Clinic
Spinal Cord Injury Risk Factors: The Mayo Clinic
Spinal Cord Injury Facts and Figures at a Glance: National Spinal Cord Injury Statistical Center

Types of Spinal Cord Injuries

The effects of a spinal cord injury vary according to its type, the severity of the injury, and the location of the injury on the spinal column. A traumatic spinal cord injury damages the nerve fibers passing through the injured area of the spine, usually causing permanent disability or loss of movement (paralysis) and sensation below the site of the injury. Additional damage will most often occur over days or weeks following the initial trauma due to fluid accumulation from bleeding, swelling, and inflammation around the spinal cord.

How Are Spinal Cord Injuries Classified?

Spinal cord injuries are classified as either partial or complete, depending on the amount of the spinal cord damaged. In a partial cord injury, or incomplete injury, the spinal cord remains partially intact and able to carry some messages to and from your brain. Survivors of a partial spinal cord injury may retain some sensation and motor function below the affected area.

What Do Spinal Cord Injuries Affect?

Impairments caused by spinal cord injuries are wide ranging and may include:

  • Motor deficit
  • Sensory deficit
  • Breathing difficulty
  • Bowel and/or bladder dysfunction

With a spinal cord injury, paralysis can be sudden and immediate. The extent of paralysis depends on the severity of the injury as well as what parts of the body it affects. Paralysis results from damage to the nerves carrying sensory information and will often affect the arms, legs, or trunk. It can affect only the one side of the body, or both. Paralysis can also affect nerves which control the heart, lungs, glands, intestines, speech, behavior and cognitive ability.

Unfortunately, 99 percent of traumatic spinal cord injuries will lead to one of the following types of paralysis:

  • Paraplegia: When the injury only affects the lower body, it is called paraplegia. Paraplegia results when an injury to the spinal cord is below the first thoracic spinal nerve. Paraplegics retain movement and sensory abilities in their arms but will experience impairment of leg movement or have complete loss of leg movement all the way up to the chest. About 52 percent of spinal cord injury survivors are considered paraplegic.
  • Quadriplegia, or tetraplegia, refers to paralysis that involves the majority of the body, including the arms and legs. Quadriplegia/tetraplegia can also affect the abdominal and chest muscles, making breathing difficult. This type of paralysis is a result of a spinal cord injury above the first thoracic vertebra. Approximately 47 percent of spinal cord injury survivors are considered quadriplegic/tetraplegic.

SCI Sources:

Types of Spinal Cord Injury: BrainandSpinalCord.org

Types of Paralysis: Apparelyzed.com

Spinal Cord Injury Complications

Secondary complications occur as a direct result of a spinal injury and are a major health issue for those living with a SCI. While loss of sensation and movement are the most common spinal cord injury complications, other systems in the body can be significantly affected.

Spinal cord injury complications, such as pressure sores, urinary tract infections, spasticity, and osteoporosis, if not treated, can lead to serious illness or death.

Pressure sores (skin breakdown): Also called decubitus ulcers, pressure sores are dangerous spinal cord injury complications. Pressure sores are caused when an individual sits or lies in the same position for a long period of time. The pressure prevents blood from reaching the skin causing the skin to die. People with spinal cord injuries are particularly susceptible to pressure sores since damage to the spinal cord keeps messages of pain and discomfort from reaching the brain, making it very difficult to identify a developing sore. Pressure sores are a common cause of hospitalization, and if not treated, cause death. The best way to prevent these sores is changing positions frequently.

Urinary tract infections: A traumatic SCI can often lead to loss of bladder control, which increases the risk of urinary tract infections. Urinary incontinence may also cause kidney infection and kidney or bladder stones. These types of spinal cord injury complications can be avoided by drinking plenty of clear fluids and using a catheter—a thin tube that is inserted into the urethra and bladder to drain urine—several times a day.

Spasticity: Muscle spasms, or spasticity, can develop after a spinal cord injury. These involuntary twitches are exaggerated reflexes caused when some of the nerves in the lower spinal cord are stimulated. Unfortunately, this does not mean that a person is recovering. The nerves, sensing discomfort or pain, are merely causing muscle contractions that the brain is no longer able to control or regulate. Almost anything can trigger spasticity. A paralyzed person cannot perform normal range of motion exercises, making their joints and muscles less flexible and therefore more prone to these types of spasms. The best way to manage or reduce spasticity is to follow a daily range of motion exercise program. If spasms become severe, medical treatments may be needed.

Osteoporosis and fractures: The majority of spinal cord injury survivors develop osteoporosis. Osteoporosis means “porous bones” and occurs when bones become weak and brittle due to lack of calcium and phosphorus. Normally, bones are kept strong by bearing weight and through regular muscle activity. In people with spinal cord injuries, however, decreased or eliminated muscle activity as well as decreased load on the bones can lead to loss of calcium and phosphorus. In the years following spinal cord injury, some degree of bone loss will occur, which, in turn, increases the risk for fractures.Using one’s legs to provide some support in transferring or standing using a standing frame is helpful in increasing the load on the bones, which can help slow down the osteoporotic process and reduce the risk of fractures.

Other Spinal Cord Injury Complications:

  • Changes to circulation and respiration
  • Changes to the kidneys and gastrointestinal system
  • Changes to muscles, joints, and bones
  • Edema, swelling caused by excess fluid trapped in the body’s tissues
  • Blood clots in the lower limbs
  • Feelings of numbness or pain
  • Skin injury
  • Bacterial infection
  • Disruption of the normal working of the tissues, glands, and organs
  • Constipation
  • Sexual difficulties
  • Abnormal sweating
  • Abnormal breathing or heart rate
  • Balance problems
  • Difficulty thinking
  • Behavioral issues
  • Difficulty speaking or swallowing
  • Vision problems
  • Chronic pain
  • Low blood pressure


Spinal Cord Injury Complications: The Mayo Clinic