Stanford’s Michael Leong, MD, on “Technology for Back Pain: Spinal Cord Stimulation”

Stanford’s Michael Leong, MD, on “Technology for Back Pain: Spinal Cord Stimulation”


MICHAEL LEONG: Wow. You guys all came
back from lunch. I’m impressed. Look, I have a few minutes
just to talk to you about some technology– [SMOOTH JAZZ PLAYS] [LAUGHTER] Is that a cue? Technology– maybe– technology
for back pain and spinal cord stimulation. And I have a few disclosures
to tell you guys about. The main one up here is that I’m
a consultant for a company that makes a spinal cord
stimulation system called Boston Scientific. But you will be your own judge
about how this lecture goes and how much I talk about
Boston Scientific systems. My pet name for this talk is
called Medicine by Edison. And the reason why
is because, you know, what this is all
about– hi, Doctor Cal– is that we’re moving electric
fields around the spinal column or outside the spinal column
in order to treat your pain. Now we’re here for
a back pain day. So I kind of have to talk
about that a little bit. But spinal cord
stimulation actually works for multiple pain
areas and pain conditions. So I put that up. But one of the most effective
things that it treats is failed back surgery syndrome. So what’s a spinal
cord stimulator? Well, a picture is
worth a thousand words. And so I put one up for you. This is what a spinal
cord stimulator lead looks like if you
take an x-ray after it’s put in on someone’s neck,
either from the back of the neck or from the side. And you can see that
it’s pretty thin. You can see that it has
these black parts, which are the metal contacts. And what that does
is it actually allows us to be able to
control the electricity that goes towards your
spinal column in order to treat the painful areas. But before we go and
talk more about this, we kind of have to understand
the history of how we got there in the first place. And I don’t know
how many of you guys know about this– I didn’t
know about it before– but this is called a torpedo fish. And they also nickname
it an electric ray. And so what happened were
some people discovered that if you step on this–
you see the 220 volts there? You can actually get some
electricity into the body and basically treat
your gout and arthritis. This was a less desirable system
for spinal cord stimulation. And so what ended up happening–
we had to wait until, what, 1745 to get
this Leyden jar. And the Leyden jar–
why is that important? It’s a capacitor. So we needed to
develop, humanity needed to develop
something where it could generate electricity,
store it, and then give it when you want it to. Then we fast forward
to approximately 1965 where these two gentlemen
Wall and Melzack wrote on a paper napkin this. And this seems
really, really simple. It’s a very simple theory. But it’s revolutionary
to pain control. And the reason why is
because they postulated that when you stimulate the
area around a painful area– if you stimulate around the
painful area and not this pain area itself, you can
actually decrease the pain in the spinal
cord or in the brain. So the development
progressed to this. And I think many
of you have seen these transcutaneous electrical
nerve stimulation systems, right? You see people get
these gel pads on. They put the gel pads
where their pain is, either on their shoulder
or on their knee. And you can get this
tingly sensation that’s less painful
than the pain, or it drops the pain down. You can’t use it all the time. But you can use it frequently. And you can use it
throughout the day. It’s not a medicine. It’s not anything that
will make you have side effects from it, really. Now it went beyond that though,
So instead of just going on the outside of the body,
Norm Shealy, a neurosurgeon– he took that gate
control theory, or that gate theory hypothesis,
and said, look, this is 1967. I’m a neurosurgeon. Why are we doing all this stuff
on the outside of the body? Why don’t we put it on
the inside of the body? I can put leads near
the spinal column near the dorsal columns
of the spinal cord in order to treat pain. And what happens is, if
you look at this picture, you’ll see that there
are different structures in different areas
when you stimulate it from the middle of
the spinal column, from the dorsal columns,
that will get areas that people have pain in. So people, when
you have back pain, it’s not just only in your back. It kind of radiates all over. Goes down your leg, like
the back of the leg, near the middle there. Goes down the front of
the leg for some people. So you have to put the leads
out just a little bit more. And it may even go almost to the
stomach a little bit sometimes. And so depending on where
you put these spinal cord stimulator leads will help
determine the combination that’s good for treating you. We have to go a little bit
into what nerve conduction is, because we’re actually
putting electricity on the spinal column. But we actually have
electricity going through us all the time right now. Right? Because we’re moving. Our nerves are firing. And what happens in the body is
that we’re actually converting chemistry to electricity. We have these changes
of sodium and potassium that we all had at
grade school, or learned at grade school, that would
change the chemical structure and cause a firing in
the axons or the nerves so that we can do things,
so that we can sense things. Now spinal cord stimulation
goes the other direction. Basically, we are
actually using electricity to fire the nerves
directly and also cause changes in
neurochemistry as well. And what you can see up here
is that there is this line, and you’ve got these
black areas which you have these metal contacts. And these contacts
can be varied. They can change to be
either positive or negative. The positive ones here,
the purple ones there, those are anodes. They go over areas where you
don’t want to stimulate it. The green ones over here,
cathodes, they go over areas where you do want to stimulate. And you can move it
along the spinal column. And what happens is, you
can use either one lead over the spinal cord– most
people have two in place, if you ask them. And then sometimes,
people have been working with even putting
three different spinal cord stimulator leads in in order
to treat very complex pain problems that go deeper
into the spinal cord or to the side, et cetera. Now I get this question all
the time about why– why do you guys put these spinal cord
stimulator leads in so high? I’ve got back pain down here. How come you’re
putting these things in higher at about T8 or T9? And the reason why is,
when you look anatomically, the spinal nerves actually
come up much higher. Your spinal column–
believe it or not, the spinal nerves end
at about L1 or L2. And so even though we are
putting the leads in higher, we’re still trying to treat
your low back and the pain that radiates to your legs as well. OK. So you got all this information. You have the packets
from different companies where you looked it
up online in order to find out what’s
spinal cord stimulator. So what happens when
you come visit someone like a pain management
physician who does these things? What are they going to ask you? Well, you know, you’ve been
through all of this morning, or most of it,
which is– one, do you have a pain problem that’s
going to respond really well to spinal cord stimulation? We are here on
back pain day, so I think you can get a clue about
what responds pretty well to spinal cord stimulation. But there are other
conditions that do as well. They’re going to ask you,
have you done all the things to set you up and make it
so that you’re in good shape in order to go through and
get the spinal cord stimulator trial and implant as well? One thing is interesting
though, and I know I’m not trying
to say to have an American initiative
about smoking, but I can tell
you that tobacco– if you are smoking
tobacco, it really does affect your wound healing. And so part of our preoperative,
or part of our questions when we first meet you is, are
you smoking, not because we’re trying to be mad at anything,
but because if you do that, then your wounds will
not heal quite as well. And we don’t want to be taking
out a system for you that worked first, but then it’s
sort of not looking so good after we do the implant. Why do you have to see
a pain psychologist? OK, well, you’ve had
multiple lectures from people that are
pain psychologists. And I’m not trying
to tell you anything that hasn’t been told
already, but the thing is that this is a
requirement for us, because it’s helping you improve
your outcome for spinal cord stimulation. There are three things
that happen any time you get anything, any treatment. It could be a medicine. It could be an injection. And it definitely
is if you’re getting something that’s surgically
implanted in your back. You can either get better
with the therapy, spinal cord stimulation. You can stay the same. Or you could even
temporarily get worse, because we’re implanting
something near a really tender area. And actually, one
of the patients that we are trialing
right now on spinal cord stimulation–
that’s exactly what happened in kind of
a different sequence. At first, they had some
post-surgical pain. So they’re sore. And I’m sorry about
that, but that’s kind of what happens when
you do the trial, especially when you’ve had multiple
surgeries before. Second thing is then, it
wasn’t seeming to work. But now, three or four days
later, he’s getting 60% to 70% pain relief, which was
more than we anticipated or even expected. There are complications with
spinal cord stimulation. Most of them have to do
with changes in where the lead positioning is. But infection and
allergic reactions are also possible,
but much less likely. But when it works it
works really, really well. Failed back surgery syndrome,
or failed back syndrome, is the main one where spinal
cord stimulation works. You’re going to see some
diagnoses up here or things that you should all
know for anyone who’s had back surgery in
the past or someone who has had back problems
with degenerative disc disease, stenosis,
radiculopathy– those things. They all respond to
this kind of therapy. There have been a ton
of different studies to show the effectiveness
of it, anywhere from 1994 up through 2013. But the one that is really
raising everyone’s eyebrows, the one that is
making people excited, is this high
frequency stimulation. And the reason why is
because you can’t feel it. We went beyond the
gate control theory. We went beyond that, so that it
may be more effective than what we’ve been traditionally
doing with low frequency, and also it may last longer. We have this safe analysis
for all pain therapies where we assess the safety of it
compared to typical medicines, the appropriateness and
timing of it, the financials, believe it or not–
we have to look at it, because if we don’t look at
it, the insurance company will look at it– and then
also whether it’s effective. And we do this every
time that we’re looking at different
therapies, especially on high tech ones like this. This is an interesting picture. Remember that other
slide I showed you? The leads were
going straight up. Now we have a technology so
that we can push them out to the side. And we’re able to
capture areas that we weren’t able to stimulate
very well with just the central leads. So hopefully I’ve given
you a picture and a history about where we’ve come from,
either stepping on torpedo fish to figuring out what the gate
control theory is on a napkin, doing these TENS units and
these implantable devices. But you know, what’s right
now– the future is actually right now, because
high frequency stimulation– we’re doing the
trials on patients right now. It is already
approved and working. Dorsal root ganglion
stimulation is also something that is new and can
be helpful for many people. And finally, just like
every other technology, everything is going wireless. And this will too. Look, I hope you guys
have a great day here at back pain day. And I’m happy to answer a few
questions if Dr. Mackey and Dr. Darnell allow me to. I still have three
minutes and 30 seconds. Thank you. – Thank you very
much, Dr. Leong. Thank you. MICHAEL LEONG: I’ll try
to take three questions. How about that? OK? – Can you repeat
the question place? MICHAEL LEONG: I’ll do it. So the question is, how
invasive is the trial and the implant for therapy? And also, does it produce
epidural or fibrosis in the back or scar tissue? The truth is that the trial
is less invasive than most typical surgeries. It’s sort of like getting
an epidural tube put in, except it’s a little
stiffer because it’s got the metal parts to it. So it’s not that
invasive for the trial. For the surgery itself, it’s a
little bit more invasive than getting an epidural
catheter for labor, but it’s much less than doing
major surgery with laminectomy or fusion. The second question, does
it produce more scar tissue? Unlikely, and actually parts
of why we do spinal cord stimulation are to treat that. Yes? Good question. So can you have this even
if you haven’t had surgery, and can you have
an MRI afterwards? The quick answer is
yes, you can have it if you haven’t had
surgery but you still have back problems
that are intractable and that aren’t responding
to other things. Can you have an MRI? Yes. Different companies
have already tested up for MRIs for Tesla 1.5
for MRI compatibility with these devices. I had one question down here. Yeah? Oh, that was it? AUDIENCE: Yeah,
the MRI question. – OK, great. MICHAEL LEONG: OK,
I think that’s– – Thank you! MICHAEL LEONG: We’ve
got to get going. – Thank you so much.

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