Spinal cord injury is damage to the spinal cord as a result of a direct trauma to the spinal cord itself or as a result of indirect damage to the bones, soft tissues, and vessels surrounding the spinal cord. The spinal cord is the major bundle of nerves carrying nerve impulses to and from the brain to the rest of the body. Rings of bone called vertebrae surround the spinal cord. These bones constitute the spinal column (back bones).
Spinal cord damage results in a loss of function, such as mobility or feeling. In most people who have spinal cord injury, the spinal cord is not severed. Spinal cord injury is not the same as back injury, which might result from causes such as pinched nerves or ruptured disks. Even when a person sustains a break in a vertebra or vertebrae, there might not be any spinal cord injury if the spinal cord itself is not affected.
There are two kinds of spinal cord injury -- complete and incomplete. In a complete injury, there is no function below the level of the injury. There is no sensation or voluntary movement. In an incomplete injury, there is some functioning below the level of the injury.
Spinal cord injury occurs in various countries throughout the world with an annual incidence of 15 to 40 cases per million. For some of these people, the injury is the result of a disease, such as polio or spina bifida. However, for most, the spinal cord injury is the result of trauma. The leading traumatic cause of spinal cord injuries is automobile accidents, causing 44% of all injuries. Other causes of spinal cord injuries, in descending order of frequency, include violence (gunshot wounds, for example), falls, and sports. While sports only account for 8% of all spinal cord injuries, 60% of those sports-related injuries are a result of diving accidents. For spinal cord injuries occurring over age 45, falls overtake automobile accidents as the number one cause.
Males account for over 80% of patients with spinal cord injuries. The average patient age is 33, but the most frequent age of injury is 19.
Spinal cord injuries might result from falls, diseases such as polio or spina bifida (a disorder involving incomplete development of the brain, spinal cord, and/or their protective coverings), motor vehicle accidents, sports injuries, industrial accidents, and assaults, among other causes. If the spine is weak because of another condition, such as arthritis, apparently minor injuries can cause spinal cord trauma.
There are two types of spinal cord injuries: complete and partial. If a spinal cord injury is complete, there is no function below the point of injury. This means the patient will experience no sensation or voluntary movement and that both sides of the body, for example have both arms, will usually be equally affected. A complete injury can result in the paralysis of all four limbs (quadriplegia) or the lower half of the body (paraplegia).
For partial injuries, a patient may be able to move one limb more than the other or be able to feel more with one side than the other. The level of incomplete injuries may vary from patient to patient, and can affect the body in different ways. For example, a C-6 injury may result in having no hand control but having wrist control. A C-5 injury may deprive a patient of wrist and hand control, but not arm and shoulder control.
Aside from having a loss of sensation and movement, patients with a spinal cord injury may also experience bladder and bowel complications. Spinal cord injuries often affect fertility in males. If the spinal cord injury is high (example, C-1 or C-2), the patient may need a respirator or diaphragmatic pacemaker to breathe properly.
Other complications that may result from a spinal cord injury are an inability to regulate blood pressure, low blood pressure, reduced control of body temperature, an inability to sweat that occurs below the level of injury, and chronic pain. Patients with spinal injuries also have an increased susceptibility to respiratory disease and autonomic dysreflexia. Autonomic dysreflexia is primarily the result of the body being unable to control the blood pressure. This is especially a concern for patients who have a spinal cord injury at T-6 or above. The signal responsible for "telling" the blood vessels to relax cannot be processed because of the injury. With autonomic dysreflexia, these blood vessels intermittently remain constricted, thus elevating the blood pressure and possibly leading to life-threatening complications such as stroke. External methods of lowering the blood pressure to a safe level are often necessary.
A spinal cord injury requires immediate treatment to avoid long-term effects. In some cases, surgery might be recommended to stabilize the bones of the spine, but surgery does not necessarily reduce or repair nervous system injury. Bed rest might be needed in order for the spine to heal. After acute spinal cord injuries occur, physical therapy, occupational therapy, and other rehabilitation interventions sometimes are required. Currently, there is no cure for spinal cord injury; however, researchers continue to work on advances, many of which have resulted in a decrease in damage at the time of the injury.
One approach for treating patients with spinal cord injuries is to compensate for lost function by using neural prostheses to bypass the areas of damage. This is done by connecting electrical and mechanical devices with the nervous system to compensate for lost motor and sensory functions. For example, neural prostheses for deafness, known as cochlear implants, are now in widespread use and have been very effective in improving hearing. The first neural prostheses for patients with spinal cord injuries are now being tested.
The United States Food and Drug Administration (FDA) approved one of these devices, a prosthesis that allows basic hand control. Patients use their shoulder muscles to control the device, and with training, can perform activities of daily life that they would otherwise be unable to perform, such as using silverware, pouring a drink, answering a telephone, and writing a note.
Neural prostheses are complex and contain many intricate components, such as implantable stimulators, electrodes, leads and connectors, sensors, and programming systems. There are many technical considerations in selecting each component. The electronic components must be as small as possible. Biocompatibility between electrodes and body tissue is also necessary to prevent injury to the patient and damage to the device. Neural prostheses also must be evaluated for usefulness and long-term safety.
Further research and an improved and increased understanding of brain circuits may eventually lead to prostheses that can provide sensory information to the brain. This would improve both the safety of the devices and the patient's ability to perform certain tasks. Devices now being developed may eventually enable people with spinal cord injuries to stand unassisted and perform other actions using signals from the brain--instead of muscles--to control movement. Ultimately, researchers may be able to harness reflexes or the innate pattern-generating abilities of the spinal cord's central pattern generators to help people with spinal cord injuries walk.
With the current wave of new technology, it is easy to forget just how far medical science has come in treating spinal cord injuries. As recently as 50 years ago, most patients died within a few weeks from a spinal cord injury due to complications related to infections or bodily dysfunctions. Nowadays, not only do spinal cord injury patients survive, many thrive. Once the injury has been stabilized, physical therapy and advances in assistive devices allow patients to work, travel, compete in sports and raise families. Nevertheless, while the years ahead offer promise for people with spinal cord injuries, today's patients face many challenges in their everyday lives.
The effects of a spinal cord injury can vary based on the injury's location. Injuries that are sustained near the top of the spine result in more extensive disability (numbness and paralysis, breathing difficulty) than injuries low in the spine. Some common outcomes are muscle spasms, the loss of sensation in parts of the body, numbness, pain and paralysis. Death can result if there is a paralysis of the muscles that control breathing.
© Copyright 1995-2020 The Cleveland Clinic Foundation. All rights reserved.
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 06/05/2017