Ulnar Neuropathy: Sane Treatment of a Crazy Bone

Do you remember what it felt like when you banged your elbow on
a hard surface and it sent shocks through your forearm and into
your little finger? Not too pleasant, to be sure. But on the
plus side, the unpleasantness was merely temporary and, for the
time being, you remembered not to do that again.

The part of the nervous system responsible for this annoying
symptom is the ulnar nerve, a peripheral nerve-bundle whose
individual nerve-fibers originate in the spinal cord where it
passes through the neck. The nerve-fibers run most of the length
of the arm, including through the “ulnar groove” which you may
know as the “funny bone” or “crazy bone.”

Some people experience a more persisting impairment of the ulnar
nerve called ulnar neuropathy. With “-pathy” as the medical
suffix meaning illness or impairment, an “ulnar neuropathy”
means an illness or impairment of the ulnar nerve. The ulnar
nerve is vulnerable to injury or pinch in the ulnar groove for
more than one reason. First, instead of being surrounded by
soft, cushioning muscles and tendons, it is sandwiched between a
layer of skin on its exterior surface and nothing but hard bone
on its interior surface. Second, when the elbow bends, the ulnar
nerve stretches because it has to take the long way around the
elbow.

Like a telephone cable containing numerous wires, the ulnar
nerve-bundle contains many individual nerve-fibers, some of
which tell the muscles what to do and others of which carry
messages back to the spinal cord and brain about sensations
experienced by the skin and other tissues. So when the ulnar
nerve is injured, both motor and sensory symptoms are possible.
Most of the muscles of the hand receive their marching orders
via the ulnar nerve, so when the ulnar nerve is out of whack,
there can be weakness in hand muscles. The muscles that spread
the fingers and those that straighten the middle joints of the
ring and little fingers are often affected. Damage to the ulnar
nerve also causes changes in sensation. The ring and little
fingers can become numb, and so can the heel of the hand.

The ulnar nerve can come to harm in more than one way. For some
people the problem might result from leaning on their elbows too
much. This can compress the ulnar nerve within the ulnar groove.
Granted, many people lean on their elbows without damaging their
ulnar nerves, but like most things in medicine, an ulnar
neuropathy is usually caused by a combination of factors, and it
is likely that some people are more vulnerable than others based
on their particular anatomies. Of course, rearranging one’s
anatomy, as for example from a preceding elbow fracture, may
also put one at risk for an ulnar neuropathy.

Another way to injure the ulnar nerve is by over-stretching it.
In the author’s clinical practice a thin, young lady with loose
elbow-joints who worked as an emergency medical technician
injured her ulnar nerves repeatedly while lifting heavy
patients. For her, it was a problem that wouldn’t go away, and
she eventually changed professions.

Although, as discussed, the ulnar nerve at the elbow is
especially vulnerable to injuries, it can also come to harm by
getting compressed or pinched by nearby abnormal tissues. The
usual culprits are tendons, ligaments, blood vessels, cysts and
scars.

Sometimes, an ulnar neuropathy is the leading symptom of a
“polyneuropathy,” meaning that all the peripheral nerves in the
body are somewhat impaired, but the ulnar nerve is the first one
to cause symptoms noticeable to the affected individual.
Polyneuropathy is not the result of injury, but can be seen in a
variety of illnesses, including diabetes, alcoholism and also on
an inherited basis.

Diagnosing an ulnar neuropathy starts with the story of the
symptoms and a physician’s examination. The physician might
subsequently order nerve conduction testing which looks at the
nerve and muscle electricity, and can determine the degree of
impairment. Moreover, nerve conduction studies can also evaluate
other nerves to see if the ulnar nerve is the only one impaired,
or merely one of many.

What if a simple injury to the ulnar nerve at the elbow is
diagnosed? What can be expected? Fortunately, the peripheral
nerves have some capacity to heal themselves. So if the degree
of nerve impairment is not too severe, conservative treatment is
called for. Unfortunately, there are no conservative treatments
that have been studied by good, randomized, controlled trials, a
form of evaluation in which the outcome of a treated group of
patients is compared to that of an untreated group. Randomized,
controlled trials are the gold standard for deciding whether or
not a treatment is effective, so in this case all we have to go
on is “clinical judgment” and observation.

A typical conservative treatment consists of putting a sport-pad
(not a medical brace) on the elbow with the foam covering the
ulnar groove. This accomplishes two things. First, if the elbow
gets leaned on, then the nerve is still protected. Second, a
well-fitting pad also prevents excessive elbow-bending
(including during sleep) that overstretches the nerve and
re-injures it. In addition, eating nutritious, well-rounded
meals, together with vitamins, gives the ulnar nerve the
building-blocks it needs in order to make the best possible
recovery.

If the nerve injury is severe, or fails to respond to
conservative treatment, then surgery might be beneficial. When
the nerve is tied up in scar tissue or compressed by nearby
abnormal tissues, a simple release operation might suffice in
which the nerve is freed up. Otherwise, in a procedure called
“anterior transposition” the nerve is transferred out of the
ulnar groove so it is out of harm’s way from leaning on the
elbow, and also gets to take to the short way around when the
elbow is flexed.

Neurosurgical researchers at Radboud University Nijmegen in The
Netherlands conducted a randomized, controlled trial of patients
with ulnar neuropathy at the elbow in which half the patients
received simple release surgery and the other half received
anterior transposition. In this study there was no difference in
outcomes between the two surgeries. About two-thirds of the
patients in each group obtained an outcome that was considered
either excellent or good. However, there were more complications
in the patients receiving the anterior transposition procedure,
so the results of this study favored the simple release approach.

(C) 2005 by Gary Cordingle