Nervous System: An Overview of the Peripheral
Guest: Dr. Abhay Varma - Neurosurgery
Host: Dr. Linda Austin – Psychiatry
Linda Austin: I’m Dr. Linda Austin. I’m interviewing Dr. Abhay Varma, who is
Assistant Professor of Neurosurgery here at the Medical University of South
Carolina. We’re going to be talking,
today, about surgical treatment of the peripheral nerves. And, first, just the basics, Dr. Varma, the
peripheral nerves are, what? How would
you explain the difference between the central nervous system and the
Abhay Varma: The peripheral nerves are
the projections, basically, of the central nervous system into the peripheral
parts of the body, carrying signals from the nervous system to the peripheral
parts of the body and, also, signals from the peripheral parts of the body to
the nervous system.
Linda Austin: So, just to put it in
really sort of simple language then, the nerves that go from the spinal column
out through the torso, out through the chest, to the arms and the legs?
Abhay Varma: And back from these organs
into the spinal column.
Linda Austin: Now, one of the types of
surgery, I understand, that you do, so- called entrapment, or to relieve
entrapment situations, what are some common examples of that?
Abhay Varma: The most common is what we
call carpal tunnel syndrome, where the median nerve is trapped by a fibrous
band in the wrist and leads to numbness and, later stages, even weakness in the
hands. Less common ones being the ulnar
nerve entrapment of the elbow, or even things like hemorrhagic parastatic,
where there’s a nerve going into the thigh that gets entrapped in the upper
part of the thigh, causing numbness in the front of the thigh. Or rare ones like the thoracic outlet
syndromes and suprascapular syndromes, etc.
Linda Austin: So, then, basically, the
nerve is getting entrapped in a band of fiber and that can happen in the wrist,
in the thigh, in the elbow, sometimes up by the shoulder. Okay, let’s take, maybe, one of the most
common ones, the carpal tunnel syndrome.
What causes that?
Abhay Varma: It’s a usually a band
called the flexor retinaculum, which is present at the wrist. This band runs from one wrist bone to the
other, kind of creating a little canal through which the median nerve
passes. The median nerve supplies the
outer part of the hand, the thumb and the first two digits, and, also, some
muscles of the hand. If this fibrous
band gets thick, it narrows down the space in the canal through which the
median nerve passes, causing pressure on the median nerve. The person can, then, experience sensory
symptoms with numbness or pins and needles sensations in the distribution of
the nerve involving the thumb and the index and middle finger. Symptoms are generally worse at night and
sometimes can wake the person from sleep.
In later stages, if the muscles are also involved, it can cause thinning
of the hand or even weakness of the hand.
Austin: Sometimes that happens because
of overuse, is that right?
Dr. Abhay Varma: That’s right.
Austin: Because of typing and so forth?
Dr. Abhay Varma: Typing, or people who are involved in
professions where there’s repetitive and forceful movement at the wrist joint,
also, in certain medical conditions, like hypothyroidism, acromegaly, obesity,
can even flare up during pregnancy. But,
usually, most commonly, now, we are seeing in folks who are using keyboards for
very extended periods of time.
Austin: Now, if someone who did
experience in pregnancy, I know that sometimes you can treat it conservatively,
to begin with, with just a hand brace, if it’s likely to be a temporary sort of
Dr. Abhay Varma: Yeah.
Austin: But, obviously, that doesn’t
always work. What’s the next level of
Dr. Abhay Varma: Well, as you said, first, we have to look for
an underlying cause that can be treated.
For example, if we know it’s a pregnant lady, then we, obviously, wait
for the pregnancy to be over. And, in
most cases, it resolves on its own. We
also want to make sure that any underlying causes are identified and treated,
like hypothyroidism, which is a problem with the hormones, or acromegaly, which
is a condition where there’s an excess of hormones of a certain type in the
body. We have to look for those
conditions, treat them and, also, while we are waiting for those conditions to
be treated, symptomatically treat this condition by using a brace, like you
But if it doesn’t
help and we have ruled out any underlying conditions and conservative treatment
with a brace is not helping, the next step is, depending on a patient’s degree
of discomfort, we pursue a full investigation with nerve conduction
studies. And if it is established and is
not seen to be improving with conservative treatment, we will do surgery.
Austin: So, talk a little bit about that
surgery. First of all, the anesthesia,
is it general or local?
Dr. Abhay Varma: Most of the time, it is done under local
anesthesia, unless the patient prefers to have general anesthesia.
Austin: And, how long does it take?
Dr. Abhay Varma: The surgery itself doesn’t take more than 10 to
Austin: Oh, that’s quick. It must be a fairly simple surgery then. What are you actually doing during the
Dr. Abhay Varma: What we do is, depending on what kind of
incision the surgeon is comfortable with, we make a small incision on the wrist
that extends from the crease of the wrist into the hand. Then we go down through the fat under the
skin and identify the band that I was talking about and open that band and
release the median nerve. Once that is
done, we make sure all the bleeding is controlled and we close the skin over
it, without closing the band again.
Austin: And then I’m sure the patient
goes home that day?
Dr. Abhay Varma: Most of the time, patients go home the same
day. We observe them for a small period
of time, maybe for about one hour or so, to make sure there is not bleeding and
that they’re comfortable, the effects of local anesthesia have worn off, and
then we send them home.
Austin: How long is the recovery period,
until they can really fully use that hand again?
Dr. Abhay Varma: Usually, it’s about, I would say, anywhere
from three to six weeks, depending on the patient’s pain threshold and if there
are any other issues. Some patients tend
to have a more inflammatory response following any kind of surgery. Their incisions can be more swollen and
painful. In other patients, the healing
is faster. But, most of the time, from
what I’ve seen, patients are able to go back to their activities by about six
Austin: Now, if the carpal tunnel
syndrome has been caused by something like too much keyboard use, too much
typing, is it likely to recur?
Austin: You mean, after surgery?
Austin: After surgery, yeah.
Dr. Abhay Varma: If you’ve done a complete release of the
flexor of the band, it’s unlikely to recur, unless there’s excessive scar
formation in that area, or if the surgeon, for some reason, was not able to
completely divide the band.
Austin: But, in most cases, the patient
can go on, do well, play tennis, or whatever.
Dr. Abhay Varma: Yes.
Once the pain and swelling of the surgery settles down, they can go back
to their usual activity.
Austin: Dr. Varma, thank you very much.
Dr. Abhay Varma: You’re welcome.
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