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Many misconceptions abound concerning spinal cord injury. For example,
many people believe that the spinal cord below the injury site dies
after injury. Others think that the injured spinal cord is like a cut
telephone wire and can be fixed by reconnecting the cut ends. Some
people think that the vertebral column is the spinal cord. Even doctors
have misleading and inaccurate ideas about spinal cord injury. For
example, many doctors casually use the word “transection”
to refer to severely injured spinal cords. The word should only be
applied to the extremely rare situation when the spinal cord has been
cut and the cut ends are separated.
Spinal cord injury usually
results from trauma to the vertebral column. Displaced bone or disc
then compresses the spinal cord. Spinal cord injury can occur without
obvious vertebral fractures and you can have spinal fractures without
spinal cord injury. It can also result from loss of blood flow to the
spinal cord. Many people may have had mild spinal cord injury without
thinking that it is spinal cord injury. For example, over a million
people per year get “whiplash” in car accidents; they often
have neck pain, weakness, and sensory loss that many last days or even
months. Athletes who play football or other contact sports often suffer
a transient loss of function that they call a “stinger”,
i.e. paralysis and sensory loss for minutes or even hours. Sometimes,
people can get spinal cord injury without any obvious cause, a
condition called transverse myelitis.
Spinal cord injuries are
usually defined by vertebral level and neurological level, as well as
severity. Vertebral levels are indicated by which bony vertebra have
been fractured or show damage. Multiple bony vertebra may be injured.
For example, an injury that causes the C5 vertebra to slip relative to
C4 may be called a C4/C5 injury because it compresses the C4 and C5
spinal cord. Spinal cord levels do not necessary correspond to
veretebral levels. For example, the C5 spinal cord lies in the C4
vertebral segment. The cord ends at the L1 vertebral level even though
the spinal roots continue and exit between the appropriate vertebral
segments.
For many years, there was no standardized way of
referring to spinal cord injury levels. Surgeons generally referred to
the injury level by the vertebra that are damaged. Neurologists and
physiatrists, however, tend to refer to the level of spinal cord injury
based on the neurological loss. Neurologists identify the level of
injury as the first segmental level that shows sensory or motor loss.
In contrast, physiatrists identify injury level from lowest spinal cord
level that has normal motor and sensory function.