A Patient's Guide to Intersection Syndrome
Introduction
Intersection syndrome is a painful condition
of the forearm and wrist. It can affect people who do
repeated wrist actions, such as weight lifters,
downhill skiers, and canoeists. Heavy raking or
shoveling can also cause intersection syndrome.
This guide will help you understand
- what part of your forearm is causing the problem
- what may have caused this condition
- what can be done to stop the pain
Anatomy
What part of the forearm is causing my pain?
The pain from intersection syndrome is usually felt
on the top of the forearm, about three inches above
the wrist. At this spot, two muscles that
connect to the thumb cross over (or intersect) the two
underlying wrist tendons (tendons connect
muscles to bones).
The two muscles that cross over the wrist tendons
control the thumb. They are the extensor pollicis
brevis and the abductor pollicis longus.
These two muscles start on the forearm, cross over the
two wrist tendons, and connect on the back part of the
thumb. When these muscles work, they pull the thumb
out and back.
The extensor carpi radialis brevis and the
extensor carpi radialis longus muscles run
lengthwise along the back of the forearm. The tendons
of these two muscles attach on the back of the hand.
The action of these two wrist tendons pulls the wrist
back, into extension.
Most of the tendons around the wrist are covered
with a thin tissue called tenosynovium.
Tenosynovium is very slippery. It allows tendons to
glide against one another and the surrounding muscles,
fat, and skin with very little friction.
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Related Document: A
Patient's Guide to Wrist Anatomy
Causes
What caused my condition?
If you overuse the wrist extensor tendons, the
slippery tenosynovial lining may become inflamed from
the constant rubbing against the two thumb muscles. As
the tenosynovium becomes more irritated and inflamed,
it swells and thickens. You feel pain when you move
your wrist because the swollen tendons are rubbing
against the thumb muscles.
Wrist extensor tendons work like the bow used by
violin players. The wrist extensor tendons are like
the bow, and the thumb muscles are like the strings.
As the wrist curls down and in, the wrist tendons rub
back and forth against the thumb muscles. The friction
builds up, much like the effect of rubbing two sticks
together. This leads to irritation and inflammation of
the tenosynovium covering the wrist extensor
tendons.
The wrist extensor tendons are strained by any
activities that cause the wrist to curl down and in,
toward the thumb. These wrist movements are especially
common in downhill skiers when they plant their ski
poles deeply in powder snow. The same movement is
involved when pulling a rake against hard ground.
Racket sports, weight lifting, canoeing, and rowing
can also stress the wrist extensor tendons.
Symptoms
What does intersection syndrome feel like?
The friction on the wrist tendons causes pain and
swelling in the tenosynovium that covers the tendons.
The friction hampers the smooth gliding action. You
may hear a squeaking sound and feel creaking as the
tendons rub against the muscles. This is called
crepitus. You may have swelling and redness at
the intersection point. Pain can spread down to the
thumb or up along the edge of the forearm.
Diagnosis
What tests will my doctor run?
Doctors usually make the diagnosis of intersection
syndrome during a physical examination. Most of the
time no special tests are required.
The main challenge is distinguishing intersection
syndrome from de Quervain's tenosynovitis. De
Quervain's tenosynovitis is a condition that is very
similar to intersection syndrome.
Related Document: A
Patient's Guide to de Quervain's Tenosynovitis
Both syndromes involve inflammation in the tendons
of the wrist. However, the pain begins in different
spots. Intersection syndrome causes pain at the
intersection point, about three inches up the forearm.
De Quervain's tenosynovitis causes pain along the edge
of the wrist, closer to the hand. Your doctor will
examine your forearm and wrist carefully to locate
exactly where your pain is coming from.
Treatment
What treatment options are available?
Nonsurgical Treatment
It is most important to stop or change activities
that are causing your symptoms. Take frequent breaks
when doing repeated hand and thumb movements. Avoid
repetitive hand motions such as heavy grasping,
wringing, or turning and twisting movements of the
wrist. Downhill skiers may get relief by avoiding
heavy planting and dragging of their ski poles and by
getting a shorter pole with a smaller basket
diameter.
Keep your wrist in a neutral alignment. In other
words, keep it in a straight line with your arm,
without bending it down and in. You may be issued a
special forearm and thumb splint called a thumb-spica
splint. It keeps the wrist and lower joints of
the thumb from moving. By resting the wrist extensor
tendons and the thumb muscles, it allows the area to
begin healing.
Anti-inflammatory medications may help control the
swelling of the tenosynovium and ease symptoms. These
medications include common over-the-counter
medications such as ibuprofen and aspirin. Ice
treatments can also help decrease swelling and relieve
pain.
If these simple measures fail to control your
symptoms, your doctor may suggest an injection of
cortisone. Cortisone is a very effective
anti-inflammatory medication. Cortisone injections
will usually control the inflammation in the early
stages of the problem. However, cortisone's effects
are generally temporary, lasting from several weeks to
months.
Your doctor may have you work with a physical or
occupational therapist. The main focus of treatment is
to reduce or eliminate the cause of the irritation to
the thumb tendons. Your therapist may check your
workstation and the way you do your work tasks. Your
therapist may give you suggestions about healthy body
alignment and wrist positions, helpful exercises, and
tips on how to prevent future problems.
Surgery
Surgery is rarely necessary to treat intersection
syndrome. In extremely difficult cases, a surgeon may
remove some of the thickened tenosynovium around the
tendons. The operation is called a tendon
release.
The tendon release procedure can usually be done on
an outpatient basis, which means that you won't have
to spend the night in the hospital. It can be done
using a general anesthetic, which puts you to
sleep, or a regional anesthetic. A regional
anesthetic blocks the nerves going to only a certain
part of the body. Injection of medications similar to
lidocaine can block the nerves for several hours.
You may get an axillary block, which puts
the arm to sleep, or a wrist block, which puts
only the hand to sleep. It is even possible to perform
the surgery by simply injecting lidocaine around the
area of the incision.
The first step is to make a small
incision over the spot where the two muscles cross
over the two wrist tendons.
The surgeon identifies the irritated tendons, and
then separates and removes the inflamed
tenosynovium from the tendons.
The skin is then stitched together, and your
hand is wrapped in a bulky
dressing.
Rehabilitation
What can I expect after treatment?
Nonsurgical Rehabilitation
If nonsurgical treatment is successful, you may see
improvement in four to six weeks. You may need to
continue wearing your thumb splint to control
symptoms. Try to do your activities using healthy body
and wrist alignment. Limit activities that require
repeated motions of the wrist and thumb.
After Surgery
A period of rehabilitation is needed after surgery.
Pain and symptoms generally begin to improve after
surgery, but you may have tenderness in the area of
the incision for several months.
At first, take time during the day to support your
arm with your hand elevated above the level of your
heart. You should gently move your fingers and thumb
from time to time during the day. Keep the dressing on
your hand until you return to the doctor. Avoid
getting the stitches wet. Your stitches will be
removed 10 to 14 days after surgery.
You will probably need to attend occupational or
physical therapy sessions for six to eight weeks, and
you should expect full recovery to take several
months. You'll begin by doing active hand movements
and range-of-motion exercises. Therapists also use ice
packs, soft-tissue massage, and hands-on stretching to
help with the range of motion. When the stitches are
removed, you may start carefully strengthening your
hand and thumb by squeezing and stretching special
putty. Therapists also use a series of gentle
stretches to encourage the wrist tendons to glide
smoothly under the thumb muscles.
As you progress, your therapist will give you
exercises to help strengthen and stabilize the muscles
and joints in your wrist and thumb. Other exercises
are used to improve fine motor control and dexterity.
Some of the exercises you'll do are designed to get
your hand working in ways that are similar to your
work tasks and sport activities.
Your therapist will help you find ways to do your
tasks that don't put too much stress on your thumb and
wrist. Before your therapy sessions end, your
therapist will teach you a number of ways to avoid
future problems. |