Spinal cord injury
The spinal cord is a bundle of nerves that carries messages between the brain and the rest of the body. Spinal cord injury is the result of a traumatic injury such as a bruise or contusion, a partial tear or a complete tear (also called a transection) in the spinal cord. It can also result indirectly from damage to surrounding bones, tissues or blood vessels, and can cause decreased or total absence of movement, sensation and organ function below the level of the injury. The most common sites of injury are the cervical (neck) and thoracic (mid-spine) areas.
There are about 12,000 new cases of spinal cord injury each year. This type of injury appears to be more common in men and young adults. According to the National Spinal Cord Injury Statistical Center, more than 265,000 people in the United States are living with a spinal cord injury. Over the past several years, motor vehicle accidents have been the cause of most incidents of spinal cord injury.
The spine consists of 33 vertebrae, including the following:
- 7 cervical (neck)
- 12 thoracic (upper back)
- 5 lumbar (lower back)
- 5 sacral (sacrum – located within the pelvis)
- 4 coccygeal (coccyx – located within the pelvis)
By adulthood the five sacral vertebrae fuse to form one bone, and the four coccygeal vertebrae fuse to form one bone. These vertebrae stabilize the spine and protect the spinal cord. In general, the higher in the spinal column the injury occurs, the more dysfunction a person will have. Injury to the vertebrae does not always mean the spinal cord has been damaged. Likewise, damage to the spinal cord itself can occur without fractures or dislocations of the vertebrae.
There are many causes of spinal cord injury. The more common injuries occur when the area of the spine or neck is bent or compressed, as in the following:
- Birth injuries – This type of injury results from the forces of labor and delivery, and usually affects the spinal cord in the neck area. Thanks to advances in methods of treating difficult and traumatic deliveries, these injuries are occurring less frequently.
- Minor injury – A seemingly minor injury can cause spinal cord damage if the spine is weakened in the area of impact. Diseases such as rheumatoid arthritis or osteoporosis can weaken the spine and make it more susceptible to injury.
- Bone fragments – Fragments of bone from an injury such as damage to the vertebrae can cut and damage the spinal cord.
- Metal fragments – Gun shots and traffic accidents are examples of occurrences that can lead to metal fragments being lodged in the spine. Like bone fragments, these too can cut and damage the spinal cord.
- Direct impact – If the spinal cord is twisted, pulled, pressed sideways or compressed it can result in spinal cord injury. If the head or neck is twisted abnormally, injury to the spinal cord can occur. Direct impact can result from falling, motor vehicle accidents, sports injuries, industrial accidents and assault.
- Falls – Falling down the stairs or from a great height can lead to spinal cord injury, especially when the neck or spine suffers from direct impact.
- Motor vehicle accidents – The driver, passenger or a pedestrian can suffer from spinal cord injury in a motor vehicle accident.
- Sports injuries – High impact sports especially pose the threat of spinal cord injuries. Diving into shallow water can also cause spinal cord injury.
- Trampoline accidents – Without proper safety devices such as coil padding or a mesh enclosure, people are susceptible to accidents on trampolines.
- Violence – This involves penetrating injuries that pierce the cord, such as gunshots and stab wounds.
Spinal cord symptoms vary depending on the severity and location of the injury. At first the patient may experience spinal shock, which results in a loss of feeling, muscle movement and reflexes below the level of the injury. Spinal shock usually lasts from several hours to several weeks. As the period of shock subsides, other symptoms appear, depending on the location of the injury.
Generally spinal cord symptoms are more severe when the injury occurs higher up the spinal cord. For example, an injury at the second and third vertebrae in the spinal column affects the respiratory muscles and the ability to breathe. A lower injury in the lumbar vertebrae may affect nerve and muscle control of the bladder, bowels and legs.
The following are the most common symptoms of spinal cord injury. However, each individual may experience symptoms differently. Symptoms may include:
- Muscle weakness or paralysis in the torso, arms or legs
- Loss of feeling in the torso, arms or legs
- Loss of sensation, such as the ability to feel heat, cold or touch
- Pain or stinging sensations due to the damage of nerve fibers in the spinal cord
- Extreme back pain
- Pressure in head, neck or back
- Numbness or tingling in hands or feet
- Muscle spasticity
- Exaggerated spasms or reflex
- Breathing problems or difficulty coughing and clearing secretions from your lungs
- Problems with heart rate and blood pressure
- Digestive problems
- Loss of bowel and bladder function
- Sexual dysfunction
- Balance or walking problems
- Oddly positioned neck or back
The symptoms of spinal cord injury may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.
Spinal cord injury is classified according to a person's type of loss of motor and sensory function. The following are the main types of classifications:
- Quadriplegia – This involves loss of movement and sensation in all four limbs. It usually occurs as a result of injury at T1 (the thoracic area of the spine) or above. Quadriplegia also affects the chest muscles. Any injuries at C4 (cervical area) or above require a mechanical breathing machine or ventilator.
- Paraplegia – This type involves loss of movement and sensation in the lower half of the body and in the legs. It usually occurs as a result of injuries at T1 or below.
- Triplegia – Consists of the loss of movement and sensation in one arm and both legs and usually results from an incomplete spinal cord injury.