by finaleditorandrew on November 6, 2010
There are many different reasons that someone could experience a spinal injury. And these causes can have an effect on symptoms and treatment options.
Trauma
Trauma (quick injury) is a common cause of spinal injuries. Automobile accidents, falls, gunshots, diving accidents, war injuries, sports injuries and any injury involving the stretching, bruising, application of pressure and severing of the spine are considered trauma. Traumatic spinal injuries are classified into five types, according to the American Spinal Injury Association (ASIA).
General Wear and Tear
Discal herniations can occur from general wear and tear, such as jobs that require constant sitting, but especially jobs that require lifting. Traumatic injury to lumbar discs commonly occurs from lifting while bent at the waist, rather than lifting while using the legs. Minor back pain is an indicator of general wear and tear that may result in a traumatic event from bending to pick up a heavy backpack from the floor or even just a pencil. When the spine is straight, such as standing or lying down, internal pressure is equalized on all parts of the discs. While sitting or bending to lift, internal pressure on the disc can move from 17 psi (lying down) to over 300 psi (lifting with a rounded back).
The common “slipped disc” (contents of the disc move or slip into the spinal nerve canal) occurs when the disc membrane covering (the annulus fibrosis) is compressed on the front (stomach side) while sitting or bending, and extruded (stretched) thinly on the rear (back side). The combination of membrane thinning from stretching and increased internal pressure results in the rupture of the confining membrane (annulus fibrosis). The jelly-like contents of the disc then move into the spinal canal, pressurizing the spinal nerves, producing intense and usually disabling pain.
Tumor
Spinal tumors, including meningiomas (usually benign tumors that develop in the membrane that surrounds the spinal cord and brain), ependymomas (a tumor that arises from the ependyma, a tissue of the central nervous system and is spinal when found in adults and intracranial in children), astrocytomas (a tumor of the central nervous system), and metastatic cancer (disease that has spread from one part of the body to another through blood vessels or the lymphatic system) can result in back pain.
Ischemia
Ischemia is the restriction of blood supply to an area and can lead to damage or dysfunction of tissue around the spinal cord. Dissecting aortic aneurysms, emboli and arteriosclerosis are just some ways that blood supply could be restricted from the tissue around the spinal cord.
Developmental Disorders
Spinal injuries that occur while the spine is developing can be considered birth disorders, like spina bifida and can often be corrected by surgery soon after birth.
Neurodegenerative Diseases
Friedreich’s ataxia and spinocerebellar ataxia are genetic diseases that affect motor movement and muscular coordination. In the former, the spinal cord becomes thinner and nerve impulses are reduced due to lack of insulation around the nerve cells.
Additional Causes of Spinal Injuries and Back Pain
by finaleditorandrew on November 6, 2010
TRAUMA CLASSIFICATION
The American Spinal Injury Association (ASIA) defined an international classification based on neurological levels, touch and pinprick sensations tested in each dermatome, and strength of ten key muscles on each side of the body, i.e. shoulder shrug (C4), elbow flexion (C5), wrist extension (C6), elbow extension (C7) and hip flexion (L2). Traumatic spinal cord injuries are classified into five types by ASIA and the International Spinal Cord Injury Classification System.
- A indicates a “complete” spinal cord injury where no motor or sensory function is preserved in the sacral segments S4-S5. Since the S4-S5 segment is the lower segmental, absence of motor and sensory function indicates “complete” spinal cord injury.
- B indicates an “incomplete” spinal cord injury where sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5. This is typically a transient phase and if the person recovers any motor function below the neurological level, that person essentially becomes a motor incomplete, i.e. ASIA C or D.
- C indicates an “incomplete” spinal cord injury where motor function is preserved below the neurological level and more than half of key muscles below the neurological level have a muscle grade of less than 3.
- D indicates an “incomplete” spinal cord injury where motor function is preserved below the neurological level and at least half of the key muscles below the neurological level have a muscle grade of 3 or more.
- E indicates “normal” where motor and sensory scores are normal. Note that it is possible to have spinal cord injury and neurological deficit with completely normal motor and sensory scores.
In addition, there are several clinical syndromes associated with incomplete spinal cord injuries.
- The Central Cord syndrome is associated with greater loss of upper limb function compared to lower limbs.
- The Brown-Séquard syndrome results from injury to one side of the spinal cord, causing weakness and loss of proprioception on the side of the injury and loss of pain and thermal sensation of the other side.
- The Anterior Spinal syndrome results from injury to the anterior part of the spinal cord, causing weakness and loss of pain and thermal sensations below the injury site but preservation of proprioception that is usually carried in the posterior part of the spinal cord.
- Tabes Dorsalis results from injury to the posterior part of the spinal cord, usually from infectious diseases such as syphilis, causing loss of touch and proprioceptive sensation.
- Conus Medullaris syndrome results from injury to the tip of the spinal cord, located at L1 vertebra.
- Cauda Equina syndrome is, strictly speaking, not really spinal cord injury but injury to the spinal roots below the L1 vertebra.
One can have spine injury without spinal cord injury. Many people suffer transient loss of function (”stingers“) in sports accidents or pain in “whiplash” of the neck without neurological loss and relatively few of these suffer spinal cord injury sufficient to warrant hospitalization. In the United States, the incidence of spinal cord injury has been estimated to be about 35 cases per million per year, or approximately 10,500 per year. In China, the incidence of spinal cord injury was recently estimated to be as high as 65 cases per million per year in urban areas. If so, assuming a population of 1.3 billion, this would suggest an incidence of 84,500 per year.
The prevalence of spinal cord injury is not well documented in many large countries. In some countries, such as Sweden and Iceland, registries are available. About 450,000 people in the USA live with spinal cord injury (1 in 670), and there are about 11,000 new spinal cord injuries every year (1 in 30,000). The majority of them (78%) involve males between the ages of 16-30 and result from motor vehicle accidents (42%), violence (24%), or falls (27%). This is likely due to increased risk-taking behavior in men.