A Patient's Guide to Radial Tunnel Syndrome
Introduction
Radial tunnel syndrome happens when the
radial nerve is squeezed where it passes
through a tunnel near the elbow. The symptoms of
radial tunnel syndrome are very similar to the
symptoms of tennis elbow (lateral
epicondylitis). There are very few helpful tests
for radial tunnel syndrome, which can make it hard to
diagnose.
This document will help you understand
- what parts of the elbow are affected
- the causes of radial tunnel syndrome
- ways to make the pain go away
Anatomy
What is the radial tunnel?
The radial nerve starts at the side of the
neck, where the individual nerve
roots leave the spine. The nerve roots exit
through small openings between the vertebrae. These
openings are called neural foramina.
The nerve roots join together to form three main
nerves that travel down the arm to the hand. One of
these nerves is the radial
nerve. The nerve passes down the back of the upper
arm. It then spirals outward and crosses the outside
(the lateral part) of the elbow before it winds
its way down the forearm and hand.
On the lateral part of the elbow, the radial nerve
enters a tunnel formed by muscles and bone. This is
called the radial
tunnel.
Passing through the radial tunnel, the radial nerve
runs below the supinator
muscle. The supinator muscle lets you twist
your right hand clockwise. This is the motion of using
a screwdriver to tighten a screw.
After the radial nerve passes under the supinator
muscle, it branches out and attaches to the muscles on
the back of the forearm.
Related Document: A
Patient's Guide to Elbow Anatomy
Causes
What causes the pain of radial tunnel syndrome?
Pain is caused by pressure on the radial nerve.
There are several spots along the radial tunnel that
can pinch the nerve. If the tunnel is too small, it
can squeeze the nerve and cause pain. Repetitive,
forceful pushing and pulling, bending of the wrist,
gripping, and pinching can also stretch and irritate
the nerve.
Sometimes a direct blow to the outside of the elbow
can injure the radial nerve. Constant twisting
movements of the arm, common in assembly work, can
also pinch the radial nerve and lead to radial tunnel
syndrome.
Symptoms
What does radial tunnel syndrome feel like?
The symptoms of radial tunnel syndrome are
tenderness and pain on the outside of the elbow. The
symptoms of radial tunnel syndrome are very similar to
the symptoms of tennis elbow. As in tennis elbow, pain
from radial tunnel syndrome often starts near the
lateral epicondyle. (The lateral epicondyle is
a bony point on the outside of your elbow joint.) The
pain gets worse when you bend your wrist backward,
turn your palm upward, or hold something with a stiff
wrist or straightened elbow.
Related Document: A
Patient's Guide to Lateral Epicondylitis
One difference between radial tunnel syndrome and
tennis elbow is the exact location of the pain. In
tennis elbow, the pain starts where the tendon
attaches to the lateral epicondyle. In radial tunnel
syndrome, the pain is centered about two inches
further down the arm, over the spot where the radial
nerve goes under the supinator muscle. Radial tunnel
syndrome may also cause a more achy type of pain or
fatigue in the muscles of the forearm. Nerve pressure
inside the radial tunnel leads to weakness in the
muscles on the back of the forearm and wrist, making
it difficult to steady the wrist when grasping and
lifting. It can even lead to wrist drop,
meaning the back of the hand can't be cocked up. Skin
sensation is not changed because the sensory portion
of the radial nerve branches off above the elbow and
does not enter the radial tunnel.
Diagnosis
How will my doctor know I have radial tunnel
syndrome?
The diagnosis of radial tunnel syndrome can be
difficult. Many cases are initially diagnosed as
tennis elbow. Tests don't always help tell the two
conditions apart.
Your doctor will take a detailed medical history.
You will be asked questions about your pain, your
activities, and any past injuries to your elbow.
Your doctor will then do a physical examination to
look for the most painful spot. The prodding and
movement may hurt. But it is important that your
doctor know exactly where and when you have pain.
Pinpointing the source of the pain will be most
helpful in determining whether you have radial tunnel
syndrome or tennis elbow.
You may do some tests of the radial nerve. An
electromyogram (EMG) tests to see if the
muscles of the forearm are working properly. If the
test shows a problem with the muscles, it may be
caused by a problem with the radial nerve. The
nerve conduction velocity (NCV) test measures
the speed of an electrical impulse as it travels along
the radial nerve. If the speed is too slow, then the
nerve is probably pinched.
These tests are not very accurate in diagnosing
radial tunnel syndrome. Many people who have radial
tunnel syndrome will have normal EMG and NCV test
results. Your doctor will consider all parts of the
examination in diagnosing whether or not you have a
problem with radial tunnel syndrome.
Treatment
How can I make my pain go away?
Treating radial tunnel syndrome can be frustrating,
for you and your doctor. Getting your symptoms under
control and helping you regain the use of your elbow
can be a challenge.
Nonsurgical Treatment
The most important part of your treatment is to
avoid the activity that caused the problem in the
first place. You need to avoid repetitive activities
that require your wrist to be repeatedly bent
backwards. Repeated use of the wrist in twisting
motions (such as using a screwdriver) also make the
problem worse. If your work tasks caused your
condition, you need to modify your work site or your
duties. This is crucial for treatment to be
successful. You need to take frequent breaks as you
work and play. You also need to limit heavy pushing,
pulling, and grasping.
If symptoms are worse at night, you may want to
wear a lightweight plastic arm splint while you sleep.
This limits your elbow movements at night and eases
further irritation. This may let the elbow rest,
giving the nerve time to recover from irritation and
pressure.
Doctors commonly have their patients with radial
tunnel syndrome work with a physical or occupational
therapist. At first, your therapist will give you tips
on how to rest your elbow and how to do your
activities without putting extra strain on your elbow.
Your therapist may apply ice and electrical
stimulation to ease pain. Exercises are used to
gradually stretch and strengthen the forearm and
muscles.
Surgery
Sometimes symptoms of radial tunnel syndrome aren't
relieved, even after many months of nonsurgical
treatment. In these cases, surgery may be the best
treatment option. It is generally considered a last
resort.
The goal of surgery for radial tunnel syndrome is
to relieve any abnormal pressure on the nerve where it
passes through the radial tunnel. The surgeon begins
by making an incision along the outside of the elbow
and down the forearm, near the spot where the radial
nerve goes under the supinator muscle.
Soft tissues are gently moved aside so the surgeon
can check the places where the radial nerve may be
getting squeezed within the radial tunnel. The nerve
can be pinched in many spots, so it is important to
check all the areas that may be causing problems. Any
parts of the tunnel that are pinching the nerve are
cut. This expands the tunnel and relieves pressure on
the nerve. At the end of the procedure, the skin is
stitched together. The following images show each
step
Radial tunnel surgery can usually be done as an
outpatient procedure. This means you won't have to
stay in the hospital overnight. Surgery can be done
using a general anesthetic, which puts you to
sleep, or a regional anesthetic. A regional
anesthetic blocks nerves in only one part of your
body. In this case, you would have an axillary
block, which would affect only the nerves of the
arm.
Rehabilitation
What can I expect after treatment?
Nonsurgical Rehabilitation
If nonsurgical treatments are successful, you may
see improvement in four to six weeks. Your physical or
occupational therapist will work with you to ease
symptoms and improve elbow function. Special exercises
may be used to help the radial nerve glide within the
radial tunnel. Treatment progresses to include
strengthening exercises that mimic daily and work
activities.
You may need to continue wearing your wrist strap
during the day and the elbow pad or splint at night to
control symptoms. Try to do your activities using
healthy body and wrist alignment. Limit activities
that require repeated hand and forearm motions, heavy
grasping, and twisting motions of the arm and
hand.
After Surgery
If you have surgery for radial tunnel syndrome,
your elbow will be placed in a removable splint and
wrapped in a bulky dressing following 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 three to four
months.
You'll begin doing active forearm range-of-motion
exercises one week after surgery. Therapists also use
ice packs, soft-tissue massage, and hands-on
stretching to improve range of motion.
When the stitches are removed, you may start
carefully strengthening your hand and forearm by
squeezing and stretching special putty. Therapists
also use isometric exercises to improve forearm and
hand strength without straining the tissues near the
radial tunnel.
As you progress, your therapist will give you
exercises to help strengthen and stabilize the muscles
and joints in the wrist, elbow, and shoulder. Other
exercises are used to improve fine motor control and
dexterity of the hand.
Some of the exercises you'll do are designed get
your elbow 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 elbow. Before your therapy
sessions end, your therapist will teach you a number
of ways to avoid future problems. |