Chronic Pain
September, 2005
Pain is the body's mechanism of self-preservation. It acts as a
warning to indicate that harm or damage is happening, or is about to
happen, to tissues in our bodies. Pain may be defined as an unpleasant
sensory and emotional experience associated with actual or potential
tissue damage. The emotional component of pain is called suffering. Pain
is familiar to everyone, and yet it is so complex and subjective that
it cannot be easily described or treated.
It is estimated that 30 to 40 million Americans a year suffer
from pain that does not respond to aspirin or ibuprofen. Many of these
people are older adults. In some patients, the pain may have begun with
an initial incident, such as a fall or accident or serious infection, or
an underlying medical condition, such as arthritis or cancer. However,
some people suffer chronic pain in the absence of any past injury or
evidence of physical damage. Chronic pain is longstanding pain that
persists beyond the usual recovery period or occurs along with a chronic
health condition. Because this pain is not protective and is not a
result of an ongoing injury, it is referred to as "pathological" and is
therefore treated as a condition, not as a symptom.
Chronic pain may affect people to the point that they cannot
work, eat properly, participate in physical activity, or enjoy life.
Estimated costs for treating chronic pain, both directly and indirectly,
are close to $50 billion a year.
Neurosurgeons treat chronic pain with state-of-the-art medical
technology. The most commonly treated conditions that cause pain are
atypical facial pain, failed spinal surgery, phantom limb pain, stroke,
and headache.
One form of facial pain called trigeminal neuralgia can be very
debilitating and painful. Some patients have described it as being
stabbed in the face with an electrical bolt. The pain can last for
seconds, disappear, and then return without any warning. If medications
have proven ineffective in treating trigeminal neuralgia, there are
several surgical procedures which may help control the pain.
Microvascular decompression involves microsurgical exposure
of the trigeminal nerve root, identification of a blood vessel that
might be compressing the nerve, and gentle displacement of it away from
the point of compression. "Decompression" may reduce sensitivity and
allow the trigeminal nerve to recover and return to a more normal,
pain-free condition.
Radiofrequency rhizotomy involves treating trigeminal
neuralgia through the use of electrocoagulation (heat). It is also used
to treat pain in any area of the spine - cervical, thoracic, or lumbar.
Glycerol rhizotomy utilizes glycerol injected through a
needle into the area where the nerve divides into three main branches.
The goal is to selectively damage the nerve in order to interfere with
the transmission of the pain signals to the brain.
Stereotactic radiation is a method in which computer-guided
radiation is aimed precisely at an appropriate target. Over a period of
time and as a result of radiation exposure, the slow formation of a
lesion in the nerve interrupts transmission of pain signals to the
brain.
Motor cortex stimulation is another option, but is often
considered a last resort because it can be very difficult to predict
which patients may benefit. While about 50 percent of patients
experience pain relief, it tends to be short-term.
Deep brain stimulation (DBS) is a surgical technique which
involves the placement of a fine electrode (wire) into specific parts of
the brain. Most commonly, DBS is used to treat Parkinson’s disease, but
it can also be utilized for the relief of pain. DBS works by delivering
a continuous electrical pulse to regions of the brain involved in the
processing of pain signals. The exact mechanism by which this creates
pain relief is yet to be fully understood. The advantages of this
technique are that it is reversible, nondestructive, and can be modified
by adjustment of the stimulator settings after implantation. DBS helps
up to 80 percent of patients in whom it is used. Recent studies have
indicated that DBS is most effective in the treatment of intractable
back pain. The rate of reduction in pain varies from patient to patient,
but on average, pain is cut in half.
Spinal cord stimulation is a pain relief technique that
delivers a low-voltage electrical current continuously to the spinal
cord to block the sensation of pain. It works by stopping painful
impulses from reaching the brain. It may be effective in treating
refractory pain from prior back surgeries, chronic sciatica, nerve
damage, and peripheral vascular disease. Researchers have reported that
about 60 percent of people receiving spinal cord stimulation have pain
reduction or relief when surveyed one to two years after having the
procedure.
As with any surgical procedure, there are risks involved. A
patients’ age, medical condition, and symptoms must be taken into
consideration before any of the above-mentioned procedures can be
considered.