Friday, January 13, 2012

The Pain Truth: How and Why We Hurt

By Robert Roy Britt
LiveScience Managing Editor
posted: 31 January 2006
08:19 am ET

Some 50 million U.S. residents live with chronic pain, experts estimate. Pain forces an estimated 36 million of them to miss work every year and results in roughly 70 million doctor visits.
Yet scientists know very little about how pain works. They can't even agree on a definition.
They do agree it's a huge problem.
"Pain is a silent epidemic in the United States," says Kathryn Weiner, director of the American Academy of Pain Management.
Real numbers are hard to get at. A Gallup Poll done in 2000 found that 80 percent of American believe pain is part of getting old, and 64 percent said they'd see a doctor only if their pain became unbearable. More than a quarter of them figured there is no solution to their pain.
"Pain has significant impact on the pain sufferer and their family," Weiner says. Pain and its treatment "represents a major problem confronting our modern culture."
What is pain?
If you suffer chronic pain, you'll probably find little solace in the fact that doctors and scientists don't understand it very well, and that just popping an aspirin is clearly far form a cure-all.
In fact experts can't even agree on what pain is.
"Pain is complex and defies our ability to establish a clear definition," Weiner says. "Pain is far more than neural transmission and sensory transduction. Pain is a complex mixture of emotions, culture, experience, spirit and sensation."
The American Academy of Pain Medicine isn't much help either. In its online FAQ, under the heading "What is pain?" you'll find this answer: "It is an unpleasant sensation and emotional response to that sensation."
There are several ways to define pain, however, and knowing which you have is important for considering how to treat it.
What we know
One way to divide pain (and perhaps conquer it) is to distinguish between acute and chronic, explains Sally Lawson, a professor of physiology at the University of Bristol in the UK.
Acute pain is what you get when you hit your thumb with a hammer, should you choose to do so. You can also achieve it with a twisted knee or a burn.
Chronic pain is long-term, continuous and far more frustrating. It can result from physical injury, viral infections of the nerve, or arthritic damage to joints and degeneration of bones, Lawson writes.
Scientists also distinguish between evoked pain (use the hammer on your thumb to demonstrate this type) and the spontaneous variety, for which there is no obvious external cause.
One type of chronic pain, called neuropathic, results from damaged nerves rather than the original injury. However, recent research by Lawson and a colleague suggests this pain may sometimes be transmitted by the undamaged nerves.
Not so simple
If it were all that simple, pain probably wouldn't hurt so much. But there's a lot more to it.
"Acute pain is usually evoked, but chronic pain can be evoked or spontaneous," Lawson explains. "Chronic pain often includes spontaneous pain, and spontaneous pain may be ongoing, unpleasant, often burning pain, or it can be an intermittent sharp stabbing or shooting pain, or both."
And that's just the half of it. There are other ways to define and discuss pain.
Meanwhile, scientists are getting closer to understanding the nature of pain by analyzing the types of nerve fibers involved in its transmission, how the signals get to your brain, and how the information is processed.
Nerves in the body serve to warn us when something is acutely dangerous, such as a hot surface, or when our body needs rest or repair. And yes, sometimes those nerves just seem to annoy.
Thousands of pain-sensing nerve endings can be packed into tiny spaces in your fingers, between the vertebrae of your back, and just about everywhere else.
There are several types of nerves that sense cold, warmth pressure, pain and more. The nerves that sense and transmit pain are called nociceptors (pronounced no-sih-SEP-turs). There are more in your fingers and toes, where injury is more likely, than in other parts of your body.
Nociceptors transmit electrical signals to your spinal column. When the cause of pain gets stronger, they fire more rapidly and intensely.
Thinking about it
In the spinal cord, the electrical pain signals trigger release of chemicals called neurotransmitters, which activate other nerve cells that process and transmit the information to the brain.
Important decisions occur in the spinal column: Acute pain like that from touching a hot surface raises a red flag and is routed to the brain immediately. Weaker messages are given less priority, so that you don't overreact to a minor scrape.
They type of pain you feel—acute or chronic—probably depends in part on the type of nociceptive fiber that is sends the initial signal, according to Lawson. "The larger fibers convey electrical impulses very rapidly to the brain, and are thought to cause sharp pricking pain, while the very fine fibers cause ongoing burning, very unpleasant sometimes called ‘unbearable' pain" because of its persistence.
Pain signals are process in the brain's thalamus, a sort of switching station. The thalamus forwards the message to three places:
  • Somatosensory cortex (physical sensation)
  • Limbic system (emotional feeling)
  • Frontal cortex (limbic system)
The brain can do more than just initiate a quick retreat from the source of pain. It might signal nerve cells to release painkillers, such as endorphins.
Chronic pain, for which there is often no obvious source, if often more complex and poorly understood. It's generally defined as pain that lasts more than six months.
Mayo Clinic researchers say chronic pain, which might result from inflammation, can be amplified and distorted like music turned up beyond a speaker's capability, causing pain out of proportion to the source. Beyond that, however, they and other researchers admit many types of chronic pain are poorly understood.
What to do
Only specialists can give proper advice for individual conditions. But all agree that curing chronic pain requires a proactive approach on the part of the sufferer.
Educate yourself, they say, and seek advice of multiple experts. And don't rely on outdated advice.
Many people figure pills are the best way to alleviate chronic pain. But exercise can be an important aspect to treatment.
"Years ago, people who were in pain were told to rest," says Edward Laskowski, a rehabilitation specialist and co-director of the Sports Medicine Center at the Mayo Clinic in Rochester, Minn. "But now we know the exact opposite is true. When you rest, you become deconditioned—which may actually contribute to chronic pain."

Learn More
The path to pain reduction starts with education, experts say. While extraordinary claims and unproven methods can fill a typical Internet search, here are some reliable sources:

Tuesday, January 10, 2012

Ouch! Why Women Feel More Pain

By LiveScience Staff
posted: 24 October 2005

Women feel more pain than men, studies have shown. New research reveals one reason why.
Women have more nerve receptors, which causes them to feel pain more intensely than men, according to a report in the October issue of the journal Plastic and Reconstructive Surgery.
On average, women have 34 nerve fibers per square centimeter of facial skin. Men average just 17.
"This study has serious implications about how we treat women after surgery as well as women who experience chronic pain," said Bradon Wilhelmi, a member of the American Society of Plastic Surgeons and author of the study. "Because women have more nerve receptors, they may experience pain more powerfully than men, requiring different surgical techniques, treatments or medicine dosages to help manage their pain and make them feel comfortable."
Earlier this year, separate research found that women report more pain throughout their lifetimes, in more areas of their bodies and for longer durations.

Tuesday, January 03, 2012

Back Pain And Fractures

Thoracic Spinal Fusion

The rods are secured with
two screws
in each vertebrae.
This feels very

Chronic pain often presents sufferers with a real "catch 22" dilemma. If they talk about their pain, they risk being perceived and labeled as hypochondriacs, or even worse?fakers or malingerers. On the other hand, if they hide their pain, others don't believe the pain is significant. It is enough to tax the patience of the most stoic person....

Compression and Wedge Fractures

Thomas A. Zdeblick, M.D.
Professor and Chairman Orthopaedic Surgery
University of Wisconsin
Madison, WI, USA

What is a Compression/Wedge Fracture?
A compression fracture is a common fracture of the spine. It implies that the vertebral body has suffered a crush or wedging injury. The vertebral body is the block of bone that makes up the spinal column.

Each vertebral body is separated from the other with a disc. When an external force is applied to the spine, such as from a fall or carrying of a sudden heavy weight, the forces may exceed the ability of the bone within the vertebral body to support the load. This may cause the front part of the vertebral body to crush forming a wedge shape. This is known as a compression fracture. If the entire vertebral body breaks, this is considered a burst fracture and is discussed elsewhere. The compression fracture may range from mild to severe in terms of severity. A mild compression fracture causes minimal pain, minimal deformity and is often treated with time and activity
Severe Pain
A severe compression fracture may be such that the spinal cord or nerve roots are involved, as they are draped over the sudden angulation of the spine. This may cause severe pain, a hunched forward deformity (kyphosis) and rarely neurologic deficit from spinal cord compression.

Risks - Osteoporosis - Trauma
The risk for spinal compression fracture increases with age. Osteoporosis is the most common risk facture for compression fractures. Osteoporosis is a condition in which there is thinning of the bones, weakening them. This may be due to a lack of calcium in the diet, certain medications, old age, inactivity or genetic factors. In general, some trauma occurs with each compression fracture. In cases of severe osteoporosis, the trauma may be minimal, such as, stepping out of a bathtub or lifting a heavy object. Moderate trauma is usually required to create a fracture in patients with mild to moderated osteoporosis. This may range from falling off a chair to an automobile accident. A normal spine may also suffer from a compression fracture when there is a severe forward bending injury. This most commonly occurs from a fall from a height or an automobile accident.
Nerve Injury
Neurologic injury is rare with compression fractures. The degree of neurologic injury is usually due to the amount of force present at the time of injury. If there is severe angulation of the spine secondary to a wedge fracture, this may stretch the spinal cord and create injury. This would then lead to loss of strength and sensation, as well as reflexes. In most patients with osteoporotic compression fractures, there is no neurologic injury but only pain from the fracture. However, if left untreated the fracture angulation may worsen and lead to late paralogic injury.

A compression fracture is usually diagnosed by the history, physical exam and x-rays. In any patient over the age of 60 with the acute onset of sudden low back pain, a compression fracture should be suspected. Physical exam will usually note tenderness directly over the area of pain as well as mild kyphotic deformity (e.g., a sudden angulation forward or hunched over appearance). Plain x-rays will demonstrate the wedge shape of the vertebral body on a lateral view. A CAT scan is occasionally needed to help differentiate a compression fracture from a burst fracture.

Occasionally an MRI scan is obtained to rule out disc herniation along with a compression fracture. MRI scan may also help differentiate pathologic compression fractures, that is, those that involve a tumor, from a typical osteoporotic compression fracture. In any patient with a known history of cancer, a compression fracture should tip off the physician to look for evidence of a metastatic lesion and pathologic fracture. If osteoporosis is suspected, a Bone Mineral Density (BMD) test may be ordered. This test helps determine the severity of the bone thinning. In addition, laboratory tests to look at blood count and thyroid function may be indicated as well. A decision as to whether to treat osteoporosis should be made by the
patients' primary physician.

Burst Fractures:Defined and

Thomas A. Zdeblick, M.D.
Professor and Chairman Orthopaedic Surgery
University of Wisconsin
Madison, WI, USA

What is a Burst Fracture?
A burst fracture is a descriptive term for an injury to the spine in which the vertebral body is severely compressed. They typically occur from severe trauma, such as a motor vehicle accident or a fall from a height. With a great deal of force vertically onto the spine, a vertebra may be crushed.

If it is only crushed in the front part of the spine, it becomes wedge shaped and is called a compression fracture. However, if the vertebral body is crushed in all directions it is called a burst fracture. The term burst implies that the margins of the vertebral body spread out in all directions. This is a much more severe injury than a compression fracture for two reasons. With the bony margins spreading out in all directions the spinal cord is liable to be injured. The bony fragment that is spread out toward the spinal cord can bruise the spinal cord causing paralysis or partial neurologic injury.

Also, by crushing the entire margin of the vertebral body the spine is much less stable than a compression fracture.
Nerve Injury
Neurologic injury from a burst fracture ranges from no injury at all to complete paralysis. The degree of neurologic injury is usually due to the amount of force that is present at the time of the injury and the amount of compromise of the spinal canal. With a greater amount of force, more bony fragments can be forced into the spinal canal causing greater loss of spinal cord function. This may cause loss of strength, sensation or reflexes below the level of the injury.

Typically, in a burst fracture that occurs at the junction of the thoracic and lumbar spines paralysis of the legs and loss of control of the bowel and bladder may result. In an incomplete spinal cord injury only partial paralysis or reflex loss is seen. With mild burst fractures only transient symptoms may be present or no neurologic injury may be present.

Severe Pain
Burst fractures cause severe pain. Typically, this is pain at the level of the fracture, that is, in the back. However, pain may also be present in the legs following the distribution of the affected nerves. Many patients complain of an electric shock type sensation into their legs when there is spinal cord compression. Most patients with a burst fracture are unable to walk immediately after the injury. Seldom, the patient may walk away from an accident and still have a burst fracture. However, often the amount of pain that is present is severe enough that patients know it is a good idea not to walk.

At the scene of the accident, patients complaining of severe back pain should not be placed into a seated for flexed position. They should be kept lying flat and transported in the flat position. A patient who stands or sits with a burst fracture may increase their neurologic injury. Burst fractures require immediate medical care by an orthopedic or neurosurgeon trained in spinal surgery. The patient should be transported to an emergency room and x-rays obtained.

The diagnosis of a burst fracture is usually made by x-rays and a CAT scan. Occasionally, an MRI scan may be ordered as well, in order to assess the amount of soft tissue trauma, bleeding or ligament disruption. The review of the CAT scan and x-rays allows the treating physician to make a determination as to the level of the fracture, whether it is a compression fracture, burst fracture or fracture dislocation, and to determine the amount of spinal canal compromise and spinal angulation. All of these factors enter into the treatment decision process.

The physical exam should be performed to document both spinal deformity, that is, angulation of the spine or tenderness of the spine at the level of fracture, as well as, a neurologic exam.

Neurologic exam should include testing of the muscle strength, sensation and reflexes of the lower extremities, as well as, testing of bowel and bladder sphincter control.