Thoracic Spinal Cord Injury
Written by Andrew Sarski on July 30, 2013
Thoracic Spinal Cord Segments and Function
Determining the exact level of a thoracic spinal cord injury is critical in making accurate predictions about what specific parts of the body may be affected by loss of function and paralysis. The level of a spinal cord injury is assigned according to the location of the injury on the spinal column vertebra. The following are the spinal cord segments contained within the thoracic spinal cord, and their overall function:
- T1: Neck extensors; flexes wrist; supplies small muscles of the hand
- T1-T6: Controls intercostals and the trunk above the waist
- T7-L1: Controls abdominal muscles
Thoracic Injury Symptoms
Injury to thoracic spinal cord levels T1 to T8 typically results in the inability to control abdominal muscles, which affects overall trunk stability. The lower the level of the injury on the spinal cord, the less severe the associated symptoms. Injury to level T9 to T12 of the thoracic spinal cord results in partial loss of trunk and abdominal muscle control. In addition to paraplegia (weakness or loss of function in the legs), thoracic injuries can also cause bowel, bladder and sexual dysfunction, and loss of physical sensation. Because this area of the spinal cord controls the signals to some of the back and abdominal muscles, most patients with this type of injury initially require the use of a brace to provide extra stability to the trunk.
Causes of Thoracic Injuries
Injury to the spinal cord occurs when the bony protection surrounding the cord is harmed, often stemming from a sudden, traumatic blow to the spine that fractures, compresses, bursts, dislocates, or crushes one or more of the vertebrae. Because the ribs protect the thoracic segments of the spinal cord – which makes thoracic spinal cord injuries less common – most injuries to this portion of the spinal cord are the result of high-speed motor vehicle accidents. Other possible causes of thoracic spinal cord injuries include gunshot or knife wounds that penetrate or sever the spinal cord. Additional damage may occur over the days or weeks following the initial injury, due to swelling, bleeding, inflammation and fluid accumulation in and around the spinal cord.
Thoracic Injury Treatment
The main goal of treatment for thoracic spinal cord injuries is protecting the spinal cord. If the spinal cord is compressed, surgery is required to relieve pressure on the spinal cord, remove any bone fragments from the spinal canal, and stabilize the spine. If the vertebrae are weakened by fracture or another consequence of trauma, they may not be able to support the normal weight from the body and protect the spinal cord as they should. If this is the case, a combination of metal screws, plates and rods may be used to help hold the vertebrae together and stabilize the spinal cord until the bones can heal. After the initial treatment is completed, additional treatment is typically geared towards rehabilitation, which includes methods to help the patient maximize function through the use of assistive devices and physical and occupational therapy.
Consequences of Thoracic Spinal Cord Injury
When the thoracic segment of the spinal cord suffers injury, the result is typically paraplegia, or a loss of sensory and motor function in the lower half of the body. Because the thoracic spinal cord is not close in proximity to the brain and lumbar cord, regeneration of sensory and motor axons to restore function isn’t easy. However, a majority of people with mid-thoracic injuries are actually able to recover a substantial amount of motor and sensory function, even those with spinal cord injuries initially diagnosed as “complete.”
When a person sustains a spinal cord injury, he or she may be told that the consequences of the injury have been classified based on the American Spinal Injury Association (ASIA) scale: A, B, C, D, or E. The following describes the ASIA Impairment Scale:
- A: Complete – No motor or sensory function is preserved in the sacral segments S4-S5.
- B: Incomplete – Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5.
- C: Incomplete – Motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3.
- D: Incomplete – Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more.
- E: Normal – Motor and sensory function is normal.
Thoracic Injury Prognosis
Thoracic spinal cord injuries disconnect the lower thoracic and lumbosacral spinal cord from the brain, and a patient’s best chance of survival following this type of traumatic injury is prompt treatment. In many cases, early decompression of the spinal cord and stabilization of the spine through surgery leads to more successful recovery. Aggressive rehabilitation and physical therapy following surgery also maximizes recovery, the majority of which occurs within the first six months after the initial injury. In general, any remaining loss of function that is present after 12 months is likely to become permanent. With the aid of assistive devices though, even people with severe spinal cord injuries can remain active and productive members of society. Although most doctors tend to be pessimistic about recovery from thoracic spinal cord injuries, with advances in modern spinal cord injury treatment, many victims of thoracic spinal cord injury are able to survive the injury and live close to a normal lifespan.