Spine Information
Low Back Pain (Overview)
Table of Contents
The spine is one of the most important parts of your body. Without
it, you could not keep yourself upright or even stand up. It gives
your body structure and support. It allows you to move about freely
and to bend with flexibility. The spine is also designed to protect
your spinal cord. The spinal cord is a column of nerves that connects
your brain with the rest of your body, allowing you to control your
movements. Without a spinal cord, you could not move any part of
your body, and your organs could not function. This is why keeping
your spine healthy is vital if you want to live an active life.
The parts of your spine and how they work
What exactly is the spine? Your spine is made up of 24 small bones
(vertebrae) that are stacked on top of each other to create the
spinal column. Between each vertebra is a soft, gel-like cushion
called a disc that helps absorb pressure and keeps the bones from
rubbing against each other. Each vertebra is held to the others
by groups of ligaments. Ligaments connect bones to bones; tendons
connect muscles to bones. There are also tendons that fasten muscles
to the vertebrae. The spinal column also has real joints (just like
the knee or elbow or any other joints) called facet joints. The
facet joints link the vertebrae together and give them the flexibility
to move against each other.
Each vertebra has a hole in the center, so when they stack on top
of each other they form a hollow tube that holds and protects the
entire spinal cord and its nerve roots. The spinal cord itself is
a large collection of nerve tissue that carries messages from your
brain to the rest of your body. In order for your body to function,
you need your nerves. The spine branches off into thirty-one pairs
of nerve roots. These roots exit the spine on both sides through
spaces (neural foramina) between each vertebra.
The spine itself has three main segments: the cervical
spine, the thoracic spine,
and the lumbar spine. The
cervical is the upper part
of the spine, made up of seven vertebrae (bones). The thoracic is
the center portion of the
spine, consisting of 12 vertebrae. The lower
portion of the spine is called the lumbar spine. It is usually
made up of five vertebrae, however, some people may have six lumbar
vertebrae. Having six vertebrae does not seem to cause a problem.
Below the lumbar spine is the sacrum. The sacrum is actually a group
of specialized vertebrae that connects the spine to the pelvis.
During development (those nine months before birth), these vertebrae
grow together (or fuse) creating one large "specialized"
vertebral bone that forms the base of your spine and center of your
pelvis. The nerves that leave the spine in the sacral region control
the bowel and bladder functions and give sensation (feeling) to
the crotch area.
 The normal spine has an "S"-like curve when looking at
it from the side. This allows for an even distribution of weight.
The "S" curve helps a healthy spine withstand all kinds
of stress. The cervical spine curves slightly inward, the thoracic
curves outward, and the lumbar curves inward. Even though the lower
portion of your spine holds most of the body's weight, each segment
relies upon the strength of the others to function properly.
Now, let' s look at the specific parts that make up your spine:
Vertebrae
The individual bones of the spine are the vertebrae.
These are the building blocks of the spinal column. The vertebrae
protect and support the spinal cord. They also bear the majority
of the weight put upon your spine. The body of each vertebra is
the large, round portion of bone. The body of each vertebra is attached
to a bony ring. When the vertebrae are stacked one on top of the
other, this ring creates a hollow tube where the spinal cord passes
through.<
The bony ring attached to
the vertebral body consists of several parts. First, the laminae
extend from the body to cover the spinal canal, which is the hole
in the center of the vertebrae. Second, the spinous process is the
bony portion opposite the body of the vertebra. You feel this part
if you run your hand down a person's back. Then there are two transverse
processes (little bony bumps), where the back muscles attach to
the vertebrae. Finally, the pedicle is a bony projection that connects
to both sides of the lamina.
The vertebra, like all bones, has an outer shell called cortical
bone that is hard and strong. The inside is made of a soft, spongy
type of bone called cancellous bone.
Intervertebral Disc
The intervertebral discs are flat, round "cushions" that
act as shock absorbers between each vertebra in your spine. There
is one disc between each vertebra. Each disc has a strong outer
ring of fibers called the annulus, and a soft, jelly-like center
called the nucleus pulposus.
The annulus is the disc's outer layer and the strongest area of
the disc. It also helps keep the disc's center intact. The annulus
is actually a strong ligament that connects each vertebra together.
The mushy nucleus of the disc serves as the main shock absorber.
The nucleus is made up of tissue that is very moist because it has
high water content. The water content helps the disc act like a
shock absorber - somewhat
like a waterbed mattress.
Facet Joint
The facets are the "bony knobs" that meet between each
vertebra to form the facet joints that join your vertebrae together.
There are two facet joints between each pair of vertebra, one on
each side. They extend and overlap each other to form a joint between
the neighboring vertebra facet joints. Without the facet joints,
you would not have flexibility in your spine, and you could only
move in very straight and stiff motions.
The facet joints are what are known as synovial joints. A synovial
joint, such as the knee or elbow, is a structure that allows
movement between two bones. In a synovial joint, the ends of the
bones are covered with a material called articular cartilage. This
material is a slick, spongy material that allows the bones to glide
against one another without much friction.
Surrounding the facet joint is a watertight sack made of soft tissue
and ligaments. This sack creates what is called the "joint
capsule". The ligaments are soft tissue structures that hold
the two sides of the facet joint together. The ligaments around
the facet joint combine with the synovium to form the joint capsule
that is filled with fluid (synovial fluid). This fluid lubricates
the joint to decrease the friction, just like oil lubricates the
moving parts of a machine.
Neural Foramen
The neural foramen is the opening between every two vertebrae where
the nerve roots exit the spine. The nerve roots travel through the
foramen to reach the rest of your body. There are two neural foramina
between each pair of vertebrae - one on each side. Without the foramen,
nerve signals could not travel to and from the brain to the rest
of your body. Without nerve signals, your body would not be able
to function.
Spinal Cord and Nerve Roots
The spinal cord is a column
of millions of nerve fibers that run through your spinal canal.
It extends from the brain to the area between the end of your first
lumbar vertebra and top of your second lumbar vertebra. At the second
lumbar vertebra, the spinal cord divides into several different
groups of fibers that form the nerves that will go to the lower
half of the body. For a small distance, the nerves actually travel
through the spinal canal before exiting out the neural foramen.
This collection of nerves is called the cauda equina while it is
still inside the spinal canal.
A protective membrane called the dura
mater covers the spinal cord. The dura mater forms a watertight
sack around the spinal cord and the spinal nerves. Inside this sack,
the spinal cord is surrounded by spinal fluid.
The nerve fibers in your spinal cord branch off to form pairs of
nerve roots that travel through the small openings (foramina) between
your vertebrae. The nerves in each area of the spinal cord connect
to specific parts of your body. This is why damage to the spinal
cord can cause paralysis in certain areas and not others -- it depends
on which spinal nerves are affected. The nerves of the cervical
spine go to the upper chest and arms. The nerves in your thoracic
spine go to your chest and abdomen. The nerves of the lumbar spine
then reach to your legs, bowel, and bladder. These nerves coordinate
and control all the body's organs and parts, and let you control
your muscles.
The nerves also carry electrical
signals back to the brain that allow you to feel sensations. If
your body is being hurt in some way, your nerves signal the brain
that you have been hurt. Damage to the nerves themselves can cause
pain, tingling, or numbness in the area where the nerve travels.
Paraspinal Muscles
The paraspinal muscles refer
to the muscles next to the spine. They support the spine and are
the motor for movement of the spine. Your joints allow flexibility
and your muscles allow mobility. There are many small muscles in
the back - each controlling some part of the total movement between
all the vertebrae and the rest of the skeleton. These muscles can
be injured directly, such as when you have a pulled muscle or muscle
strain of the back muscles. The muscles can also cause problems
indirectly, such as when the muscles are in spasm after injury to
other parts of the spine.
When you experience a muscle spasm, it is because your muscle tightens
up and will not relax. These spasms usually occur as a reflex -
meaning that you cannot control the contraction of the muscles.
When any part of the spine is injured, including: a disc, ligaments,
bones, or muscles, the muscles automatically go into spasm to reduce
the motion around the area. This protective mechanism is designed
to protect the injured area.
When muscles are in spasm they produce too much of the chemical,
lactic acid. Lactic acid is a waste product produced by the chemical
reaction inside muscle cells that must occur to allow the muscle
to contract. If the muscle cell cannot relax, too much lactic acid
builds up inside the muscles. The buildup of lactic acid causes
a painful burning sensation.
The main reason that lactic acid builds up inside the muscle cells
is that when the muscles contract, the small blood vessels traveling
through the muscles are pinched off (just like a tube pinched between
your thumb and finger). When the muscle relaxes, the lactic acid
is eventually washed away by fresh blood flowing into the muscle
as the blood vessels open up.
Spinal Segment
Back specialists sometimes look at a spinal
segment to understand and explain how the whole spine works.
A spinal segment is made up of two vertebrae attached together by
ligaments, with a soft disc separating them. The facet joints fit
between the two vertebrae, allowing for movement, and the neural
foramen between the vertebrae allow space for the nerve roots to
travel freely from the spinal cord to the body.
The spinal segment allows us to focus on the repeating parts of
the spinal column to better understand what can go wrong with the
various parts of the spine. Sometimes problems in the spine involve
only one spinal segment, while other times the problems involve
multiple segments.
Each spinal segment is like a well-tuned part of a machine. All
of the parts should work together to allow weight bearing, movement,
and support. When all the parts are functioning properly, all spinal
segments join to make up a remarkably strong structure called the
spinal column. When one segment deteriorates to the point of instability,
it can lead to problems at that segment causing pain and other difficulties.
Now that you know the parts of the spine, let's look at the spine
itself, which has three main segments - the lumbar, thoracic, and
cervical spines.
Lumbar Spine
The lowest part of the spine is called the lumbar
spine. This area has five vertebrae. However, sometimes people
are born with a sixth vertebra in the lumbar region. The base of
your spine (sacrum) is a fusion of many bones, and when one of them
forms as a vertebra rather than part of the sacrum, it is called
a transitional (or sixth) vertebra. This occurrence is not dangerous
and does not appear to have any serious side effects.
The lumbar spine's shape has what is called a lordotic curve. The
lordotic shape is like a backwards "C". If you think of
the spine as having an "S"-like shape, the lumbar region
would be the bottom of the "S". The vertebrae in the lumbar
spine area are the largest of the entire spine, so the lumbar spinal
canal is larger than in the cervical or thoracic parts of the spine.
Because of its size, the lumbar spine has more space for the nerves
to move about.
Low back pain is a very common complaint for a simple reason. Since
the lumbar spine is connected to your pelvis, this is where most
of your weight bearing and body movement takes place. Typically,
this is where people tend to place too much pressure, such as: lifting
up a heavy box, twisting to move a heavy load, or carrying a heavy
object. Such repetitive injuries can lead to damage to the parts
of the lumbar spine.
Thoracic Spine
The thoracic spine is made
up of the middle 12 vertebra of the spine. These vertebrae connect
to your ribs and form part of the back wall of the thorax (the ribcage
area between the neck and the diaphragm). This part of the spine
has very narrow, thin intervertebral discs, so there is much less
movement allowed between vertebrae than in the lumbar or cervical
parts of the spine. It also has less space in the spinal canal for
the nerves. The thoracic spine's curve is called kyphotic because
of its shape, which is a regular "C"-shaped curve with
the opening of the "C" in the front.
Cervical Spine
The cervical spine is made
up of the first seven vertebrae in the spine. It starts just below
the skull and ends just above the thoracic spine. The cervical spine
has a lordotic curve (a backward "C"-shape) - just like
the lumbar spine. The cervical spine is much more mobile than both
of the other spinal regions - think about all the directions and
angles you can turn your neck.
Unlike the rest of the spine, there are special openings in each
vertebra in the cervical spine for the arteries (blood vessels that
carry blood away from the heart), as well as the spinal canal that
carries the spinal cord. The arteries that run through these openings
bring blood to the brain.
Two vertebrae in the cervical spine, the atlas and the axis, differ
from the other vertebrae because they are designed specifically
for rotation. These two vertebrae are what allow your neck to rotate
in so many directions, including looking to the side.
The atlas is the first cervical vertebra - the one that sits between
the skull and the rest of spine. The atlas does not have a vertebral
body, but does have a thick forward (anterior) arch and a thin back
(posterior) arch, with two prominent sideways masses.
The atlas sits on top of the second cervical vertebra - the axis.
The axis has a bony knob called the odontoid process that sticks
up through the hole in the atlas. It is this special arrangement
that allows the head to turn from side to side as far as it can.
Special ligaments between these two vertebrae allow a great deal
of rotation to occur between the two bones.
Though the cervical spine is very flexible, it is also very much
at risk for injury from strong, sudden movements, such as whiplash-type
injuries. This high risk of harm is due to the limited muscle support
that exists in the cervical area, and because this part of the spine
has to support the weight of the head. This is a lot of weight for
a small, thin set of bones and soft tissues to bear. Therefore,
sudden, strong head movement can cause damage.
Back pain can be caused by a number of spinal conditions, and below
are descriptions of various causes of discomfort:
Mechanical versus Compressive pain
Sometimes it is useful for back specialists to understand back
problems by dividing the problems into different categories. One
way to look at back pain is to divide problems into two large categories
-- mechanical back pain and compressive back pain.
Mechanical pain is often
called back strain because is linked with the movement, or "the
mechanics" of the spine. This type of pain occurs when injury
to the spine's discs, facet joints, ligaments, or muscles results
in inflammation. It is called mechanical pain because it relates
to the mechanics of your spine. The more you use the back, the more
it hurts. This pain can be caused by many conditions in the spine.
These conditions include: fractures of the vertebra, muscle strains
in the paraspinal muscles, ligament injures in the spine, and wear
and tear of the spine's joints and discs.
Compressive pain is a result
of pressure or irritation on the spinal cord, or nerves that leave
the spine. For example, if an intervertebral disc herniates (usually
called a ruptured disc) and pushes into the spinal canal, it can
cause problems with the nerve. Usually this pressure or irritation
causes pain, numbness, and muscle weakness where the nerve travels.
Each part of the spine can cause pain. It can be helpful to understand
which part of the spine is causing your back pain and whether the
pain is from a compressive or mechanical type problem.
Arthritis Pain
The term arthritis means inflammation of the joints. Arthritis
of the spine usually refers to a condition where there is inflammation
of the facet joints between the vertebrae. The pain that results
from arthritis is usually the mechanical type of back pain. If bone
spurs develop due to the arthritis and begin rubbing on the spinal
nerves, there can also be compressive type pain produced as well.
There are two types of arthritis: systemic inflammatory arthritis,
and wear-and-tear arthritis. A systemic type of arthritis is actually
a disease process that affects all the joints of the body - such
as rheumatoid arthritis. Many arthritis type diseases affect the
connective tissues of the body. All of these diseases cause inflammation
of the joint tissues and destruction of the joints. The joints of
the spine may be involved in systemic types of arthritis because
the facet joints are made up of the same tissues as any other joint.
Therefore, diseases that attack joint tissues also attack the facet
joints.
Wear-and-tear arthritis, or osteoarthritis, can result from many
things. It can come from a single injury that damages the joint.
It can also result from a lifetime of overuse of different joints
that damage the joint a little bit at a time. Doctors are now beginning
to realize that osteoarthritis also runs in families. Something
about the genetic makeup of different individuals makes them more
prone to develop osteoarthritis of various joints.
Osteoarthritis is caused by a permanent breakdown of the articular
cartilage inside the affected joint. Articular cartilage is the
material inside the joint that cushions the bones of the joints
from impact and allows smooth, gliding motions. Because damaged
cartilage cannot repair itself, it begins to fray, making it less
flexible and more prone to injury. Over time, the cartilage can
wear away completely, causing the bony surfaces of the joint to
rub directly against each other. Eventually the joint becomes worn
away and bone spurs develop around the joint.
Facet Joint Syndrome
Sometimes the facet joints are the main cause of back pain. In
many cases, the facet joints are at least part of what is causing
your back pain. When your doctor thinks the facet joints are a major
source of your pain, he may use the term "facet joint syndrome".
Facet joint degeneration, or osteoarthritis, can be caused by a
combination of aging, pressure overload of the facet joints, and
injury.
Pressure overload on the facet joints is probably caused by degeneration
of the intervertebral disc. As the discs degenerate, they wear down
and begin to collapse. This narrows the space between each vertebra.
This narrowing of the space between each vertebra affects the way
the facet joints line up. When this occurs, it places too much pressure
on the articular cartilage surface of the facet joint. The excessive
pressure leads to damage of the articular surface and eventually
the cartilage begins to wear away.
When facet joint arthritis gets bad enough, the cartilage and fluid
that lubricate the facet joints are eventually destroyed as well,
leaving bone rubbing on bone. Bone spurs begin to form around the
facet joints. When bone spurs develop, they can take up space in
the foramen (the opening between vertebrae where nerve roots exit
the spine) and press into nerve roots. As the bone spurs begin to
grow larger, they can eventually extend into the spinal canal itself.
This leads to narrowing of the spinal canal (spinal stenosis).
Pinched Nerve (Radiculopathy)
Radiculopathy is the medical
term used to describe a "pinched nerve" in the spine.
A radiculopathy occurs when a nerve is irritated by something that
is either rubbing on the nerve or pressing on the nerve. In some
cases, such as a herniated (or ruptured) disc, there may also be
a chemical reaction irritating the nerve. Chemicals released from
the inside of the disc seem to irritate nerve tissue, causing pain
and inflammation of the nerve.
Abnormal pressure or irritation on a particular nerve causes several
problems. First, there is numbness in the area where the nerve usually
provides sensation, or feeling. For example, if the nerve usually
ends in the side of the foot and supplies sensation to that area,
it will have decreased feeling, and often pain.
The key to understanding a radiculopathy is understanding that
your brain cannot tell where the problem really is. While the irritation
or pressure on the nerve may be in your back, your brain thinks
the pain is coming from your foot. In addition, the muscles that
the nerve usually controls will not work right. You will usually
have weakness in the muscles, and the reflexes controlled by the
muscles will not work. This is why doctors always check reflexes.
The body has a pretty standard wiring diagram. By determining which
reflexes are not working, the doctor can usually tell which nerve
is involved with the problem.
Things that can cause a radiculopathy include: herniated discs,
bone spurs, tumors that are growing into the nerves, and fractures
that put pressure on the nerves.
Sciatica
The term sciatica refers to a certain type of radiculopathy that
occurs in the leg. It is called sciatica because it describes the
radiculopathy that occurs when one or more of the nerves that make
up the large sciatic nerve are irritated or pinched. Therefore,
sciatica is not any different than a pinched nerve anywhere else
in the spine. It simply has its own name because it is fairly common.
It also occurs in the lumbar spine, the most common site of spinal
nerve irritation.
Sciatica is used to describe the pain
that travels from the sciatic nerve in the lumbar region into
your buttocks, back of the thighs, and sometimes calf and foot.
The pain is typically caused by irritation of the nerve roots that
join outside the spine to make up the sciatic nerve. Conditions
that can cause sciatica are: herniated discs, bone spurs, cancerous
tumors that are growing into the nerves, and fractures that put
pressure on the nerves.
Spinal Cord Pressure
We have seen how individual nerve roots are affected by pressure
and irritation -- but what about the spinal cord itself? Pressure
on the spinal cord typically results from a condition called
stenosis. Stenosis means narrowing of an opening or tube - in this
case the spinal canal.
Spinal Stenosis
Spinal stenosis is a term
commonly used to describe a narrowing of a portion of the spinal
canal. Stenosis can occur in all areas of the spine, but it is most
common in the cervical and lumbar spine. There can often be narrowing
of most of the lumbar spinal canal and of several segments of the
cervical spine. Each behaves somewhat differently.
Although there is some space between the spinal cord and the edges
of the spinal canal, this space can be reduced by many conditions.
Bone and tough ligaments surround the spinal canal. This tube cannot
expand if the spinal cord or nerves require more space. If anything
begins to narrow the spinal canal, the risk of irritation and injury
of the spinal cord or nerves increases. Some conditions that can
lead to narrowing of the spinal canal include: infection, tumors,
trauma, herniated disc, arthritis, thickening of ligaments, growth
of bone spurs, and disc degeneration.
Spinal stenosis usually occurs in older people after years of wear
and tear or degeneration of the spine. This wear and tear results
in changes in the structures around the spinal canal, such as thickening
of the large ligaments that connect the vertebra together, bone
spurs around the facet joints and disc space, and bulging of the
discs themselves. All of these changes push into the spinal canal,
making the tube of the spinal canal smaller. Eventually, there is
not enough space in the spinal canal for the nerve to comfortably
fit without causing too much pressure. Stenosis can also develop
because of injuries, infections, or tumors. Some people even have
a narrow spinal canal from birth, and this abnormality leads to
symptoms of stenosis.
The narrowing of the spinal canal can lead to irritation of the
nerves of the spine. This can cause pain and problems with the nerves
not working right. The lack of space can also cause the supply of
blood and oxygen to the spinal cord to be reduced. When the spine
needs more blood flow during increased activity, the blood vessels
may not be able to swell to get more blood to the spine. This can
lead to numbness and pain in the affected nerves. The nerves also
lose some of their mobility when the space available to them is
reduced. This leads to irritation and inflammation of the nerves.
Other symptoms of spinal stenosis include: a sensation of heaviness,
weakness, and pain when walking or standing for a long period. With
rest, these symptoms often disappear. These symptoms occur because
the nerve roots are being tampered with, upsetting the normal signals
that travel from the brain to the body. Irritation of the nerves
in the spinal canal is worse when with standing or walking because
of the mechanical compression and stretching of the nerves.
Segmental Spinal Stenosis
Segmental spinal stenosis
is a narrowing of the spinal canal in a segmented, or specific,
area. Sometimes the stenosis only occurs in a small area of the
spine, such as an area where there is a combination of bone spurs
from the facet joints in the back of the spinal canal and a bulging
disc in the front of the spinal canal. This results in narrowing
of that one area of the spine.
Segmental stenosis can occur in both older and younger people.
The symptoms of segmental spinal stenosis are similar to other conditions
of the spine. Segmental spinal stenosis can affect the nerve roots
that leave the spine at the area where the segmental stenosis occurs.
These nerves can become irritated, causing pain, numbness, and weakness
in the area the nerve travels. There can also be pressure on the
rest of the spinal nerves that must travel through the narrowed
area of the spinal canal.
Discogenic pain
Discogenic Pain is a term
back specialists use when referring to pain caused by a damaged
intervertebral disc. A degenerating disc may cause pain of the mechanical
type. As the disc begins to degenerate, there is some evidence that
the disc itself becomes painful. Movements that place stress on
the disc can result in back pain that appears to come from the disc.
This is similar to any other body part that is injured, such as
a broken bone, or even a cut in the skin. When these types of injuries
are held still, there is no pain. However, if you move a broken
bone, or the skin around a cut, it causes pain.
Discogenic pain usually causes pain felt in the lower back. It
may also feel like the pain is coming from your buttock areas and
even down into the upper thighs. The experience of feeling pain
in an area away from the real spot causing the pain is common in
many areas of the body, not just the spine. Examples include: a
person who has gallstones may feel the pain in their shoulder; or
a person experiencing a heart attack may feel pain in the left arm.
This is called radiation of the pain. It is very common for pain
produced by spine problems, such as disc problems, to be felt in
different areas of the body, including the back itself.
Bulging Disc
Bulging discs are fairly
common in both young adults and older people. They are not cause
for panic. In fact, abnormalities that show up on MRIs, such as
bulging or protruding discs, are seen at high rates in patients
both with and without back pain. Most likely, some discs begin to
bulge as a part of the aging process, and the degeneration process
of the intervertebral disc. A bulging disc is not necessarily a
sign that anything serious is happening to your spine.
A bulging disc becomes important when it bulges enough to cause
narrowing of the spinal canal. If there are bone spurs present on
the facet joints behind the bulging disc, the combination may cause
narrowing of the spinal canal in that area. This is sometimes referred
to as segmental spinal stenosis.
Herniated Disc
A herniated disc occurs
when the intervertebral disc's outer fibers (the annulus) are damaged
and the soft inner material of the nucleus pulposus ruptures out
of its normal space. If the annulus tears near the spinal canal,
the nucleus pulposus material can push into the spinal canal. This
can cause too much pressure on the spinal cord and nerve roots.
There is also some evidence that the nucleus pulposus material causes
a chemical irritation of the nerve roots. Both the pressure on the
nerve root and the chemical irritation can lead to problems with
how the nerve root works. The combination of the two can cause pain,
weakness, and/or numbness in the area of the body to which the nerve
travels. For this reason, a herniated disc usually causes pain of
the compressive type. Sometimes a herniated disc is referred to
as "slipped disc", though the disc does not actually slip.
Herniated discs are common in the lumbar spine because of all the
pressure it supports. A herniated lumbar disc often produces sciatica.
This is a condition where the lower back pain and numbness radiates
down the back of the leg, side of the calf, and possibly into the
side of the foot. You may not necessarily have much back pain. The
exact area where you will feel numbness depends on the nerve root
that is affected; the numbness could be in the inner ankle, big
toe, heel, outer ankle, outer leg, or a combination of them. Your
doctor can use this information to get an idea which nerve is affected.
Pressure on the nerve root can cause the parts of the nerve that
control the muscles not to work properly. This can result in weakness
of some muscles and may change the reflexes in certain areas. Again,
your doctor can use this information to try to determine which nerve
is involved.
The same is true for the neck. A problem stemming from the neck
may result in pain that is perceived in the arm or hand. However,
a herniated disc is much less common in the thoracic spine. This
is likely because the discs are much thinner and there is less material
in the nucleus pulposus to rupture into the spinal canal. HOWEVER,
if a herniated disc does occur in the thoracic spine, it can be
much more serious than in the lumbar spine. The thoracic spine has
very little extra room in the spinal canal. In addition, a herniated
disc in the thoracic spine puts pressure on the spinal cord - not
just a few nerve roots. Too much pressure on the spinal cord from
a herniated thoracic disc can lead to total paralysis from the waist
down.
Just because a disc has herniated does not necessarily mean that
you will need to undergo surgery. In most cases, a herniated disc
can be treated without surgery. The treatment of a herniated disc
depends on the symptoms. It also depends on whether the symptoms
are getting steadily worse -- or whether they are getting better.
If the symptoms are getting steadily worse, your doctor may be more
likely to suggest surgery. If the symptoms are getting better, your
doctor may suggest watching and waiting to see if the symptoms go
away. In many cases, the initial problems due to a herniated disc
completely resolve over several weeks to months.
In rare cases, a herniated disc in the lumbar spine area can be
so large that it fills the entire spinal canal in the area where
it ruptures. When the spinal canal fills with disc material, it
may place a great amount of pressure on the nerves. If this occurs
in the lower spine, it can lead to a condition called "cauda
equina syndrome". This problem can lead to permanent paralysis
of the muscles that control your bowels and bladder. If you lose
control over your bladder or bowels, you should contact your health
care provider immediately. These symptoms require immediate medical
attention.
Degeneration of the Intervertebral Disc
The process of degeneration
of the intervertebral disc causes many problems in the spine.
Everything you do during the day - once you stand upright - begins
to test the spine's ability to support your body weight. Over time,
these repeated daily stresses and minor injuries can add up and
begin to affect the discs in your spine. Minor injuries to a disc
may occur and not cause pain at the time. However, as they add up,
the disc eventually begins to suffer from the wear and tear - it
begins to degenerate.
There is an intervertebral disc between each of your vertebra.
The intervertebral discs are designed to absorb pressure and keep
the spine flexible by acting as cushions during body movement. The
discs work similarly to shock absorbers. They are like cushions
in running shoes; without them, a jogger would feel every pound
on the pavement, and the feet would soon tire out. Without the cushion
effect of the discs, the vertebrae in your spine would probably
fracture or break. Bones cannot sustain high stress repeatedly without
being cushioned.
A healthy intervertebral disc has a great deal of water in the
nucleus pulposus - the center portion of the disc. The water content
gives the nucleus a spongy quality and allows it to absorb spinal
stress. Excessive pressure or injuries to the disc can cause the
injury to the annulus - the outer ring of tough ligament material
that holds the vertebrae together. Generally, the annulus is the
first portion of the disc that seems to be injured. Small tears
show up as in the ligament material of the annulus. These tears
heal by scar tissue. The scar tissue is not as strong as normal
ligament tissue. Over time as more scar tissue forms, the annulus
becomes weaker. Eventually this can lead to damage of the nucleus
pulposus. The nucleus begins to lose its water content due to the
damage - it begins to dry up.
Because of water loss, the discs lose some of their ability to
act as a cushion. This can lead to even more stress on the annulus
and still more tears as the cycle repeats itself. As the nucleus
loses its water content it collapses, allowing the two vertebrae
above and below to move closer to one another. This results in a
narrowing of the disc space between the two vertebrae. As this shift
occurs, the facet joints located at the back of the spine have to
shift. This shift changes the way the facet joints work together
and can cause problems in the facet joints as well.
Bone spurs, sometimes called osteophytes, may also form around
the disc space. These bones spurs can also form around the facet
joints. This is thought to be due to the body's response to try
to stop the excess motion at the spinal segment. The bone spurs
can become a problem if they begin to grow into the spinal canal
and press into your spinal cord and nerves. This condition is called
spinal stenosis.
Segmental Instability of the Spine
Each spinal segment is like a well-tuned part of a machine. All
of the parts should work together to allow weight bearing, movement,
and support. A spinal segment is composed of two vertebrae attached
together by ligaments, with a soft disc separating them. The facet
joints fit between the two vertebrae, allowing for movement, and
the foramen between the vertebrae allows space for the nerve roots
to travel freely from the spinal cord to the body. When all the
parts are functioning properly, the spinal segments join to make
up a remarkably strong structure called the spine. When one segment
deteriorates to the point of instability, it can lead to localized
pain and difficulties.
Segmental instability occurs
when there is too much movement between two vertebrae. The excess
movement of the vertebrae can cause pinching or irritation of nerve
roots. It can also cause too much pressure on the facet joints,
leading to inflammation of facet joints. It also may cause muscle
spasms as the paraspinal muscles try to stop the spinal segment
from moving too much. The instability eventually results in faster
degeneration of the spine in this area.
It is hard to determine which problem comes first in segmental
instability. In some cases, degeneration of the disc begins the
process. Once the disc is no longer able to function normally, the
degeneration process of ALL parts of the spinal segment begins.
As the disc continues to degenerate, the facet joints become arthritic,
bone spurs form around the joints, and the segmental instability
gets worse. This cycle continues.W
Before a health care professional can diagnose your condition and
design a treatment plan, a complete history and physical examination
are necessary. There are so many possible internal causes of pain;
it is important to determine what is and is not causing the problem.
After the physician has a better idea of what is attributing to
your discomfort, diagnostic tests of some sort may be recommended.
History
First, you will be asked for a complete physical history of your
condition. This may begin by filling out a written form that asks
you a number of questions relating to your pain. The more information
you share with the provider, the easier your problem will be to
diagnose. Your physical history is important because it helps your
doctor understand: when the pain began, anything that could have
caused an injury, your lifestyle, physical factors that might be
causing the pain, and your family history of similar problems. After
reading through your written history, your physician will ask more
questions that relate to the information you have given. Some typical
questions include:
- When did the pain begin?
- Was there an injury that could be related to the pain?
- Where do you feel the pain? What is the intensity?
- Does the pain radiate to other parts of the body?
- What factors make the pain feel better or worse?
- Have you had problems with your bladder or bowels?
- Is there a history of osteoporosis in your family?
Physical Examination
After taking your history, the physician will give you a physical
examination. This allows the doctor to rule out possible causes
of pain and try to determine the source of your problem. The areas
of your body that will be examined depend upon where you are experiencing
pain - neck, lower back, arms, legs, etc. The following are some
of the things that are checked in a typical exam:
- Motion of Spine and Neck - Is there pain when you twist, bend, or move? If so, where? Have you lost some flexibility?
- Weakness
- Your muscles will be tested for strength. You might be asked to try
to push or lift your arm, hand, or leg when light resistance is put
against them.
- Pain - The doctor may try to determine if you have tenderness of certain areas.
- Sensory Changes - Can you feel certain sensations in specific areas of the feet or hands?
- Reflex Changes - Your tendon reflexes might be tested, such as under the kneecap and under the Achilles tendon on your ankle.
- Motor Skills - You might be asked to do a toe or heel walk.
- Special
Signs - The physician will also check for any "red flags" that could
indicate something other than spinal/vertebrae problems. Some signs of
other problems include tenderness in certain areas, a fever, an
abnormal pulse, chronic steroid use (leads to loss of bone mass), or
rapid weight loss.
You may be asked to take a variety of diagnostic tests. The tests
are chosen based upon what your physician suspects is the cause
of your pain. These are the most common diagnostic tests:
X-rays
An X-ray is a painless process that uses radioactive materials
to take pictures of bone. If your doctor suspects vertebral degeneration,
X-rays can be used to verify: a decrease in the height of space
between discs, bone spurs, nerve bundle sclerosis (hardening), facet
hypertrophy (enlargement), and instability during flexion or extension
of limbs. X-rays show bones, but not much soft tissue, so they will
definitely be used if fractures, infections, or tumors are suspected.
During X-rays, you will be asked to lie very still on a table and
hold certain positions while photographs are taken of your spine.
MRI Scan (Magnetic Resonance Imaging)
The MRI scan is a fairly new test that does not use radiation.
By using magnetic and radio waves, the MRI creates computer-generated
images. The MRI is able to cut through multiple layers of the spine
and show any abnormality of soft tissues, such as nerves and ligaments.
The test also can be used to verify: loss of water in a disc, facet
joint hypertrophy (enlargement), stenosis (narrowing of spinal canal),
or a herniated disc (protrusion or rupture of the intervertebral
disc).
During an MRI test, you lie on a table that slides into a machine
with a large, round tunnel. The machine's scanner then takes many
pictures that are watched and monitored by a technician. Some newer
MRI machines, called Open MRIs, are likely to be more comfortable
for patients who experience claustrophobia. The procedure takes
30-60 minutes.
CAT Scans (Computer Assisted Tomography)
The CAT scan is an X-ray test that is similar to both the MRI and
a regular X-ray, because it can show both bones and soft tissues.
CAT scans are also able to produce X-ray "slices" taken
of the spine, allowing each section to be examined separately. The
scan forms a set of cross-sectional images that can show disc problems
and degeneration of bones, such as bone spur formation or facet
hypertrophy (enlargement). CAT scan images are not as clear as either
X-rays or an MRI. To make the soft tissues easier to see, the CAT
scan is often combined with a myelogram.
Like an MRI, with a CAT scan you will lie on a table that slides
into a scanner. The scanner is essentially an X-ray tube that rotates
in a circle taking many pictures. The procedure takes 30-60 minutes.
Myelogram
A myelogram is an older test that is used to examine the spinal
canal and spinal cord. During this test, a special X-ray dye is
placed into the spinal sac. This will require a spinal tap to be
performed by your doctor. This procedure is performed by inserting
a small needle in the lower back and into the spinal canal. Through
the needle, dye is injected which mixes with the spinal fluid.
The dye shows up on X-rays. Therefore, when the X-ray is taken,
the dye outlines the spinal cord and nerve roots so that disc and
bone spur problems can be seen.
To conduct the myelogram, the patient lies on a tilting table.
As the table tilts, the movement of the dye shows the outline of
the spinal sac. X-rays are taken as the patient is titled to show
the flow of the dye through the spinal region, helping doctors determine
if there is any unusual indentation or an abnormal shape. This indentation
could be from a herniated or bulging disc, lesions, tumors, or injury
to the spinal nerve roots. The myelogram is often combined with
a CAT scan to get a better view of the spine in cross section.
In many cases, the MRI has replaced both the myelogram and the
CAT scan. Sometimes the myelogram still shows the problem better
than the MRI, but today it is used less frequently than the MRI.
Bone Scan
A bone scan can be used to locate any problem areas of the spine.
The bone scan works by injecting a radioactive chemical, sometimes
called a "tracer", into the bloodstream through an IV.
The chemical will attach itself to areas of bone that are undergoing
rapid changes. Over a period of several hours, a lot of the tracer
accumulates in the problem area(s).
A special camera is then used to take pictures of the skeleton.
The chemical tracer is radioactive, and therefore sends out radiation
that can be captured by the camera. Specific problem areas show
up on the film as dark spots or "hotspots".
A bone scan is very useful when it is unclear exactly where the
problem is in the skeleton. The ability to take a picture that lights
up the area where the problem seems to be coming from allows the
doctor to pinpoint where to look next. After locating the problem
areas, other tests can be done to show more aspects of those specific
spots. The bone scan can identify problem areas such as bone tumors
and compression fractures. A bone scan can also be used to determine
bone density and the bone-thinning condition of osteoporosis.
EMG/SSP (Electrodiagnostic Study)
An electromyogram (EMG) is a test that looks at the function of
the nerve roots leaving the spine. The test is done by inserting
tiny electrodes into the muscles of the lower extremity. By looking
for abnormal electrical signals in the muscles, the EMG can show
if a nerve is being irritated or pinched as it leaves the spine.
Think of how you test the wiring on a lamp. If you place a working
bulb into the lamp, and the bulb lights up, you assume that the
wiring is okay. However, what if the bulb does not light up? You
can safely assume that something is probably wrong with the wiring,
like the lamp is unplugged, or a short circuit has occurred. By
using the muscles like the light bulb in the lamp, the EMG is able
to determine the condition of the nerves that supply those muscles,
just like the wiring on the lamp. If the EMG machine finds that
the muscles (the light bulb) are not working properly, the doctor
can assume that the nerves (the wiring) must be getting pinched
somewhere.
Facet Joint Block
Like any joint in the body, facet joints can cause pain if they
are irritated or inflamed. The facet joint block is a procedure
where a local anesthetic medication (such as lidocaine or Novocain)
is injected into the facet joint. This same type of medication is
used by a dentist to numb your jaw, or a doctor to sew up a laceration.
The lidocaine actually numbs the area around the facet joint. If
all your pain goes away, the doctor can assume that the facet joint
is a problem.
Laboratory Tests
Further lab tests may be done to check for problems that are not
related to deterioration of the spine. Other testing can help determine
the presence of serious problems such as: an infection, arthritis,
cancer, or an aortic aneurysm. The most frequent lab test is blood
sampling.
Spinal Tap
A spinal tap is done in
order to get a sample of the cerebrospinal fluid that surrounds
the spinal cord. The fluid is usually very clear. It contains proteins,
sugar, and other substances that can be found in blood. It typically
does not contain red blood cells or many white blood cells. A spinal
tap checks the pressure and content of the fluid. Signals that there
may be problems include: evidence of bleeding, an increase in white
blood cells (infection fighting cells, dead cells are "pus"),
an increase in protein level, or inflammation. This could mean infection,
tumors, or a hemorrhage around the brain or spinal cord. To obtain
the fluid sample, a needle will be inserted into the spinal canal
in the lumbar region.
Discogram
A discogram is an X-ray
examination of the intervertebral discs. This test is used to determine
which disc(s) are damaged and if surgery is necessary. The test
is performed by injecting dye into the center of the injured disc(s).
The dye makes the disc clearly visible on X-ray film and a fluoroscope
screen. This test is better than an X-ray or myelogram for determining
if there is a disc problem. The dye helps the physician make an
accurate diagnosis. A simple X-ray shows only the vertebrae, and
a myelogram is best for assessing the spinal canal.
With a discogram, you will be given medication to help you relax,
then a local anesthetic. The procedure usually lasts about 40 minutes.
Treatment Concepts
On your first visit to a back specialist, the initial decision
that must be made is exactly how serious the problem is. Some problems
need immediate attention - possibly even surgery. However, the vast
majority of back problems do not require surgery. Once the most
likely cause of your problem has been determined (your diagnosis
has been made), you and your health care provider can decide on a
treatment plan.
A variety of treatment options exist for different types of back
pain, and in most cases, simple therapies such as mild pain medications
and rest, are effective in relieving the immediate pain. The overall
goal of treatment is: to make you comfortable as quickly as possible,
to design a program to reduce further degeneration, and to get you
back to normal activity as soon as possible. The more you know about
how your back works and what you can do to prevent further injury,
the more effective your program will be. Below are descriptions
of the most common forms of treatment, along with a brief explanation
of what each is designed to do.
"Conservative" Treatment
Back specialists often use the term "conservative treatment"
to describe any treatment option that does not involve surgery.
Therefore, you may hear, or read in your records, that your provider
is recommending a course of conservative treatment for your back
problem. Treatment for your back problem may be as simple as reassuring
you that it is not a serious problem and doing nothing but watching
and waiting. However, usually anyone who has a back problem that
becomes symptomatic should consider some preventive measures. This
usually means that you should learn more about how to protect your
back and consider beginning exercises to strengthen your back. These
exercises can be quick and easy to do, do not require any special
equipment, and can help prevent problems later.
A variety of treatment options exist for back pain that is the
result of degeneration (wear and tear) on the parts of the spine.
In most cases, simple therapies such as mild pain medications and
rest are effective. The goal of treatment is to make you feel comfortable,
reduce further degeneration, and get you back to normal activity
as quickly as possible. As a last resort, and only if all other
conservative treatments fail, surgery might be considered.
Specific Rest
Immediately after a back injury, rest is often all your back needs
to feel better. Rest is used to take the pressure off your spine
and the muscles around your spine. You should rest in a comfortable
position on a firm mattress. Placing a pillow under your knees can
also help relieve pain. Do not stay in bed for several days! Bed
rest for more than two or three days can weaken the back muscles,
making the problem worse instead of better. Even though you may
still feel some pain, a gradual return to normal activities is good
for your muscles. In most cases of sudden back pain, the sooner
you start moving again, the sooner your back pain will resolve.
If you are sent to see a physical therapist, the first few days
may be spent educating you on ways to take stress off the back while
remaining as active as possible. Short periods of rest combined
with brief exercises designed to reduce your pain may be suggested.
Medications
Mild pain medications can reduce inflammation and pain when taken
properly. Medications will not stop degeneration, but they will
help with pain control.
Aspirin
Aspirin compounds are over-the-counter pain relievers that can
help relieve minor pain and back ache. The main potential side effect
of aspirin is the development of stomach problems, particularly
ulcers with or without bleeding. You should not take aspirin if
you are pregnant. In fact, you should not take any medication unless
you have discussed the medication with your obstetrician.
NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
NSAIDs include over-the-counter pain relievers such as ibuprofen
or naproxen. These medications once were only available by prescription.
NSAIDs are very effective in relieving the pain associated with
muscle strain and inflammation. They block the inflammatory response
in joints. However, be aware that NSAIDs can decrease renal function
if you are an older patient. Excessive use can lead to kidney problems.
Again, do not take them if you are pregnant.
Non-narcotic Prescription Pain Medication
Non-narcotic analgesics (the term analgesics means "pain relievers")
address pain at the point of injury. Analgesics are ideal in the
treatment of mild to moderate chronic pain. Tylenol and aspirin
are the most widely used over-the-counter analgesics. Medications
that are analgesics and require a prescription from the doctor include
NSAIDs such as: carprofen, fenoprofen, ketoprofen, and sulindac.
To reduce any side effects: do not lie down for 15 to 30 minutes
after taking medication, avoid direct sunlight, wear protective
clothing, and sun block. Avoid using these medications if you are
pregnant, have recurrent ulcers, or liver problems.
Narcotic Pain Medications
If you experience severe pain, your health provider might prescribe
a narcotic pain medication such as codeine or morphine. Narcotics
relieve pain by acting as a numbing anesthetic to the central nervous
system. The strength and length of pain relief differs for each
drug. Narcotics can cause related side effects such as nausea, vomiting,
constipation, and sedation or drowsiness. These side effects are
predictable and can often be prevented. Common preventative measures
include: not taking sleeping aids or antidepressants in conjunction
with narcotics, avoiding alcohol, increasing fluid intake, eating
a high fiber diet, and using a fiber laxative or stool softener
to treat constipation. Remember that narcotics can be addictive
if used excessively or improperly.
Muscle Relaxants
If you are having muscle spasms, muscle relaxants can help relieve
pain, but they are only shown to be marginally effective. They also
have a significant risk of drowsiness and depression. Long-term
use is not suggested; only three to four days is typically recommended.
Antidepressants
Back pain is actually a common symptom of depression and could
be an indicator of its presence. Antidepressants can relieve emotional
stress that leads to symptoms of back pain. An important fact to
note - it seems that the same chemical reactions in the nerve cells
that trigger depression also control the pain pathways in the brain.
Some Antidepressant medications seem to reduce pain, probably because
they affect this chemical reaction in the nerve cells. Some types
of antidepressants also make rather good sleep
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