Technique offers chronic sufferers an alternative to drugs
Host Amber Smith: Upstate Medical University in Syracuse, New York, invites you to be The Informed Patient with the podcast that features experts from Central New York's only academic medical center.
I'm your host, Amber Smith.
Chronic pain can be frustrating to live with and a challenge to treat effectively. Today, I'm talking about one potential solution called neuromodulation with Dr. Vandana Sharma. She's an anesthesiologist and the director of Pain Management Services at Upstate.
Welcome back to "The informed Patient," Dr. Sharma.
Vandana Sharma, MD: Thank you, Amber. Thank you for having me on air.
Host Amber Smith: I understand a neurosurgeon implanted the first device designed to relieve intractable pain more than 50 years ago. It's more recently that these devices have proven themselves. What can you tell us about neuromodulators?
Vandana Sharma, MD: I will go back to the very basics and talk about neuromodulation. In very simple terms, neuromodulation is a way to regulate the nervous system. This is what it technically means when we use that in the sense of chronic pain, as we all know that chronic pain is carried by nerve fibers that go to and from the spinal cord.
So neuromodulation is basically using electrical signals to modulate or regulate the response of the body so that the chronic pain can be modified with more pleasant stimulation.
Or the pain can be masked in a way that it doesn't bother the patients as much as it would without neuromodulation.
Now, we know that opioids or pain medications could do that, but this is a better form of pain control because it is done in a non-pharmacologic way.
So we are just using electrical signals to their best value and help modulate the pain signals.
Host Amber Smith: Is the neuromodulation used on a temporary basis, or is it a permanent thing? In other words, if you start taking over for the nerves in a particular area, is that forever?
Vandana Sharma, MD: It can be done both ways, actually.
Neuromodulation can be done at three levels.
It could be done at spinal cord level, what we call spinal cord stimulators.
It can be done at the level of peripheral nerves, and it's termed as peripheral nerve stimulation.
And occasionally, neurosurgeons or pain physicians might also modulate at the level of dorsal root ganglion, which is, again, a part of the central nervous system as it comes out from the spinal cord, and these are called DRG stimulators, or dorsal root ganglion stimulators.
So, to answer your question whether it's temporary or permanent, it starts out as a temporary trial. That's where we actually place, the percutaneous (passing through the skin) leads. These are cylindrical plastic leads that are placed around the spinal cord. I would talk more about spinal cord stimulation here, but the similar things can be done for peripheral nerve or for DRG stimulation as well.
And these leads are placed first temporarily. These are percutaneous leads, and they're externally connected to a generator, and then the rep could actually stimulate the generator and see whether it covers the area of pain.
It's temporary left in the patient's body for about five to seven days. And during this time, the patients are made to do the routine activities, except for bending or twisting, so that the leads do not migrate. And we want to evaluate them very closely during this time: how much pain reduction they get or what are the things they couldn't do before that they could do while the neuromodulation is in effect.
If the patients report a good, sustainable pain relief, which is at least 50%, and again, 50% may make a meaningful change in somebody's life and sometimes may not make a meaningful change in somebody's life.
So, it's more important for us to know if it made a change in your quality of life. And if that happens, and you think it was useful to you, then we go ahead and do the permanent placement. We first remove the temporary leads, give the body rest for a few weeks, and then go ahead with the permanent placement.
And in that case, in addition to those leads, we also placed this pulse generator under the skin permanently.
Host Amber Smith: I see. Now you used the term DRG stimulation. What is that?
Vandana Sharma, MD: DRG stimulation, the full form is dorsal root ganglion stimulation. It is a fairly new form of neuromodulation, and in this, FDA has only cleared very certain levels which can be modulated that way, just because of the complexity of the procedure and sometimes not very well tolerated.
So, spinal cord stimulation still remains one of the most widely used ways of neuromodulation.
Host Amber Smith: So which patients are candidates for spinal cord stimulators?
Vandana Sharma, MD: Basically any patients who have intractable, neuropathic pain, and neuropathic pain means when it's originating from dysregulation of the nervous system in some part of the body.
The most common indication for placement of spinal cord stimulators is for failback surgery, which is, again, a loosely coined term for patients who undergo surgery for back pain or for neck pain, but in the end, the surgery does not relieve the pain, and they continue to have back pain and/or leg pain after the surgery.
So those are the patients that show most benefit from spinal cord stimulation.
Other than that, it can also be used for complex regional pain syndrome, which is also not very common, but a cause for severe neuropathic pain in arms or in legs. It's also used, very rarely, for peripheral neuropathic pain.
And actually, recently FDA cleared spinal cord stimulators for diabetic peripheral neuropathy. and we are using it, if in patients who have well-controlled diabetes, but the neuropathic pain bothers them the most, we could use neurostimulation for treatment of those patients as well.
Host Amber Smith: What does the stimulator, the piece that goes under the skin, what does that look like? And can you feel it or see it once it's implanted?
Vandana Sharma, MD: So there are two parts of what goes inside the body. One, as I mentioned, are the percutaneous leads. These leads are plastic cylindrical devices, and at the end of the tips of those leads are the contacts. These contacts are made of metal, and it's an inert metal, mostly platinum-based alloys. So these are the contacts that actually generate the electricity or stimulate the electric signals. the other end of this lead, two leads, is connected to a pulse generator, and that's the implantable pulse generator.
It's a thin disc, almost like a vanilla wafer thickness. And that can be implanted under the skin very next to the paraspinal (adjacent to the spine) area, so like almost four or five inches away from the midline. And in between, these leads are tunneled under the skin, so the patients do not feel the lead part of it, but they do feel the IPG (implantable pulse generator) part of that, which as I said is a thin metal device, and it's put in like almost a centimeter to 1.5 centimeters under the skin. So if they would want to touch it, yes, they could touch it, and feel it, but it's not something that would interfere with any kind of their functioning or even laying down on that side.
One more thing I would want to mention there is that when we are planning for a spinal cord stimulator placement, we always ask the patient about their sleeping patterns, like if they sleep on one side of the body versus the other, and having this thin plastic or metal thing under their skin, would that interfere there with their sleeping position in any way?
In that case, we would just put it in an area where patient would prefer it. So that discussion, all that about where to implant it, and what kind of stimulator they would need and all those, and we'll talk about that further as well. All this discussion happens beforehand.
Host Amber Smith: How long is it good for, or will it have to eventually be replaced or batteries changed or something?
Vandana Sharma, MD: That's a great question. And that's one discussion that I always make sure that I do before, we select the patients for this kind of a procedure. There are two kinds of IPGs, rechargeable, and non-rechargeable. The rechargeable ones are the newer ones, and they are made of lithium-ion batteries.
The patients have to, for a few hours in a week, they have to charge those batteries, and it definitely extends the battery life. it also depends how often you are using the spinal cord stimulation. Suppose you're using it for several hours during the day, so you know that the battery's going to be expended very soon, and that's where the rechargeable ones are better.
But even though they're rechargeable, they still have a certain battery life, and most companies say that it's anywhere between seven to 10 years. On the other hand, the more traditional ones were non-rechargeable ones. And once you placed them, they were good for about four to five years, and at the end of that period, you had to remove them and put the fresh IPG in with a new battery.
And again, it was dependent upon how much you were using and what settings you were using. So obviously if you're using it for longer time and stronger settings, the battery would run out sooner and the patient at some point, again, would need a surgery to replace it.
Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith.
I'm talking with Dr. Vandana Sharma, the director of Pain Management Services at Upstate.
For patients who want to try a neuromodulator, is this something they can seek as a first therapy, or do doctors generally want them to try medications or surgery or physical therapy before they embark on a neuromodulator?
Vandana Sharma, MD: So, again, it depends upon what kind of pain syndromes you have, and sometimes we feel that acting faster is in the best interest of the patient. But again, I would not offer an invasive procedure as my first-line management right away. And I would want to try the non-invasive or more conservative management first as the patients arrive to our clinics.
We start out with pharmacologic physical therapy, and along with that, epidural injections or some kind of injections to help them with their pain, in the beginning. But after we have seen, and we quickly arrive to a decision, in their treatment plan, how they responded to both medications, therapy, as well as the injections.
If we see a great response from the injections and medications, then we move ahead and stay on that path. However, if we do not see a great response and we are seeing a rapidly progressing neuropathic pain, for example in complex regional pain syndrome, then it's best to start with neuromodulators early on rather than waiting and letting it become more complicated.
Host Amber Smith: I was interested by how you were explaining really they get kind of a trial period with this, to see whether it's going to help them, before it actually gets implanted. Do we know about the effectiveness of modern neuromodulators? Do most patients get some relief?
Vandana Sharma, MD: For the most part, patient selection is what matters the most.
If you have selected your patient very well, and if you have prepared them psychologically as well, like what to expect and how much pain relief you get out of that. Just with any other therapy, like not just for chronic pain management, but for any other treatment plans. If the patients know exactly what to expect from the treatment and you chose it for the right indication, for the right kind of pain management, they work tremendously well, like really seriously well. But then, if you are falling out on any of these parameters, the chances of success go down. With all that said, sometimes there are complications related to the device itself.
For example, lead migration happens or lead fracture happens, and the device, which may be functioning in the beginning, may not function after that. In certain cases where we are not a hundred percent sure whether this is going to work or not, but we still feel that we have tried everything else, and this is one last resort that is left to help a patient, that's where our trial period helps us a lot, which is more like just placing two epidural leads, like you would get epidural catheter, but these are two of them and using a bigger bore needle. So it's more invasive than just placing an epidural catheter, but it is done in an outpatient setting, requiring some minimal to moderate sedation and some local anesthetic.
The patients could just arrive in an ambulatory surgery center and could get these leads placed, which stay in for five to seven days. And this gives them a good time to check whether this is a great treatment option for them or a useful treatment option for them, and, if not, then they can always decide not to go ahead with the permanent implantation.
Host Amber Smith: What are the devices made of and do you ever see patients who have, their bodies have, like a reaction to the material?
Vandana Sharma, MD: Just like any other implantable material, there are chances of body reacting, like tissue reaction might happen. It's not very common though. Like in my own personal practice I have not seen that happening a whole lot.
But yes, there are case reports of that happening. The leads are mostly made up of, plastic, but at the end, the contacts could be made of metal alloys. As I was saying, it's mostly platinum-based inert material that does not stimulate the tissue reaction.
IPG, on the other hand, again, is made of inert alloys, but they're metal.
More commonly than tissue reaction, what is seen is occasionally skin sensitivity at the site of the IPG implantation. I wouldn't say it's very common, but it can happen. And if it happens, it can be a very annoying complication from this, occasionally leading to explant (removal) a nicely functioning device.
Host Amber Smith: What do patients need to know about how the surgery is done?
How do you tell them to prepare?
Vandana Sharma, MD: So, as I was referring to earlier, the initial part, which is the percutaneous lead trial, is not really a surgical part, where we are just using two needles to place the percutaneous wires at that point. However, the second part, where we are doing the permanent implantation, this is done under general anesthesia because it's at that point that we do not need the patient's input.
We have already trialed and tested the placement of these leads at a certain level, and patients have certified pain benefit out of that. So, our job is to just mimic what we did during the trial at this time, so patients can be put to sleep. And this is a little bit more uncomfortable part of it. That's. Why general anesthesia works the best.
We make two incisions, close to four to five centimeters. One is made right in the center, in the midline. And from there, the epidural needles are again placed, the same two needles as they were placed for the trial, but this time through the incision. And then the wires, the other ends of the wires that are coming out of the spinal canal, are tunneled under the skin, using a metal tunneler, and then connected to another incision, where the pulse generator is placed. And as I was saying earlier, this is about one to one and a half centimeters under the skin. It is nicely, joined and locked in place, the leads are anchored to the skin and underlying fascia, and that's when the device is ready to go.
Host Amber Smith: How long does that take?
Vandana Sharma, MD: It's about couple hours, I would say close to like two, two and a half hours.
Host Amber Smith: And is it done in a pain management office, or is this done in a hospital?
Vandana Sharma, MD: This procedure, for its infectious risk and the involvement of the placing a surgical incision and closure, we want to be as safe as possible, and that's why it's better to do this in an operating room. I have never done this procedure outside the operating room. Whether it's in ambulatory surgery center operating room, or the main hospital operating room, that is strategically the best place to do this.
Host Amber Smith: And how soon until the patient feels a difference?
Vandana Sharma, MD: There is some incisional pain that we anticipate, right after the procedure is done, which could stay for a few days, like two to three days to up to a week after the permanent implantation. But after that, the patients come in for a follow-up visit at our clinic. That's when the sutures are removed, and we check for any signs of infection or any complications at that point.
If everything is cleared at that point, then that's when the medical reps also come and meet the patients on the same visit, and they, start increasing the settings because in the very beginning, the settings are kept at a minimal to keep patients comfortable. And it's only at the post-operative visit when we start increasing the settings to make patients more comfortable. Sometimes it might take a few weeks for us to reach the final settings, and that's when the patients get the best benefit.
Host Amber Smith: I'd like to talk about what life is like with a neuromodulator after you've recovered from the surgery. How might life change for someone after they've recovered from the surgery?
Vandana Sharma, MD: So right in the very beginning, once either the trial leads or even the permanent leads are placed, we tell the patients not to bend or twist or do anything that would make the lead migrate, as I was telling you before that one of the commonest complications from this procedure is lead migration.
And that could also cause the device to fail. I mean, after all that the patients go through to get this placed, you do not want the leads to migrate from the initial spot. And that's why no strenuous activity is advised for first three to four weeks after the permanent implantation, and slowly the body starts creating fibrous tissue around those leads, so it's hard for them to move afterwards. But the first few weeks are when they could move the most, so no such activities like bending, twisting, lifting, heavy weights or any strenuous kind of activity like running or all that should be done in the beginning.
Apart from that, patients are also advised not to turn this on when they're driving because sometimes the leads are transmitting these electrical signals, and they could go on a setting that may take your attention off from the road onto this buzzing sensation that could happen in your back. So we do not advise patients to drive with the stimulator on.
If they are going to have any surgeries later on for any other reason, it's best to turn the device off because use of electrocautery during the surgery, especially if it's closer to the device, could cause permanent damage to either to the device or the leads that are going into the spinal cord. Almost like a cardiac pacemaker or a defibrillator, where you want to be very careful about the electrocautery that is used for the surgery. So those things might change some of the ways you would want to proceed.
Host Amber Smith: Does having a neuromodulator affect whether you can go swimming?
Vandana Sharma, MD: In the beginning, we would be advised not to do swimming for like few weeks. However, after that, there is no contraindication not to do any of those desired activities.
For example, some of these patients may still want to continue doing physical therapy, as it is a very important cornerstone of recovery from pain states, and we actively tell them to go ahead and do physical therapy afterwards.
Similarly, swimming is totally fine and should not be a restrictive thing.
Host Amber Smith: Will the device show up on a metal detector or an airport screening?
Vandana Sharma, MD: These patients should tell the authorities beforehand that they have a metal device in.
So there are two concerns.
One is whether it would show up or not, and second is going through those metal detectors. If they have a strong field, they might interfere with how the stimulator is working. So it's best to disclose that in the very beginning, before you actually go through that.
And secondly, you should turn it off. It's best to just turn them off so that there's no electrical signal being transmitted between the spinal cord and this IPG, and go through the metal detector as quickly as you can, as is feasible.
Host Amber Smith: Does someone with a neuromodulator, does that affect any other health conditions they may have, either positively or negatively?
Vandana Sharma, MD: As I very briefly referenced to cardiac pacemakers or AICDs (automated implantable cardioverter defibrillators), it's not a contraindication to have a neuromodulating device when a patient already has a pacemaker or a defibrillator in place, but it could interfere significantly with electrical signals that are going that way.
So anytime we are implanting the spinal cord stimulators, in these patients, we make sure that first they talk to their cardiologist. So the team that is managing the pacemaker or a defibrillator should be consulted first. They should make concrete plans on what would happen and how close would these leads be from the pacemaker leads, because the spinal cord stimulators could be placed anywhere in the thoracic spine or up in the cervical spine, and there could be a possible interference with the electrical signals going to the heart.
So that all has to be, like a multimodal or a multi-team, kind of a multi-specialty approach to ensure that it's safe to proceed with this procedure.
Host Amber Smith: Can someone with a neuromodulator safely take aspirin or ibuprofen for a headache or something?
Vandana Sharma, MD: Yes, yes they can. But at the same time, with the patients on anticoagulants, or blood thinners, they are at higher risk for developing spinal hematomas (swellings filled with blood) in the epidural space or in the spinal space.
So, we take extra precautions in those patients for stopping these medications before we even place the spinal cord stimulator device. Anyone afterwards, we tell them to be careful, and if there are any signs or symptoms that could suggest hematoma formation, they are told to go to ED (hospital emergency department) because this can be a catastrophic complication.
Host Amber Smith: Is there maintenance involved in keeping the neuromodulator in good working order?
Vandana Sharma, MD: That information, for the most part, is given to the patients by the reps as well. And most often what I mean by that is how often to charge it, how to charge it, how to keep your charger in the best possible shape, or even a remote-control device that helps you program or go up or down on the settings.
So all those things the patients are given, very thorough instructions on.as soon as the device is implanted, and even further on, if they have any questions, concerns, these reps are available at a phone call away.
Host Amber Smith: Well, before we wrap up, Dr. Sharma, can you tell us about intrathecal pumps? .
Vandana Sharma, MD: Yes, absolutely. Intrathecal pumps are, instead of neuromodulation, they are actually directly depositing the opioid or any other form of pharmacological pain medications into the spinal canal directly. So when we take an opioid medication, or any pain medication for that matter, through the mouth or through the intravenous form, the medication has to be absorbed by the body, and then it goes to its receptors and most of these receptors are present in the spinal cord
From there they work, and also in the peripheral nervous system as well, but spinal cord is the major place where these medications act.
So the goal of doing an intrathecal pump is to place the medication very close to the targeted area. So a, plastic catheter is placed in the, spinal space, and just like a neuromodulating spinal cord stimulator, the other end of this plastic catheter is connected to a reservoir that's implanted under the skin. And this reservoir has to be filled with the pain medication every month, or depending upon how quickly the medication is being dispensed, it has to be periodically filled with the medication.
They have to come to a physician's office for that, and it continuously delivers the medication right into the spinal canal.
Host Amber Smith: So patients who qualify for a neuromodulation device, would they also be candidates for intrathecal pumps, and would they have to choose between one or the other?
Vandana Sharma, MD: Basically, the answer to this depends upon their etiology (cause) of pain.
Suppose the pain etiology is more neuropathic pain, where it's stemming from nervous system disorder, like, as I said, CRPS (complex regional pain syndrome) or failback surgical syndrome or any other neuropathies. Then neuromodulation would be the best treatment option for them. However, if we are seeing patients who are requiring opioids or other pain medications, for example, someone has spastic cerebral palsy and are requiring baclofen and require the medication to be put in close to the spinal cord at that level. Then, the intrathecal pumps would be used there.
Sometimes we see patients with both etiologies, where they have neuropathic pain and they have required opioids for a very long period of time, and you want to cut down on the amount that they would use. Then they may be candidate for both, but it's a very rare indication.
Host Amber Smith: So it sounds like this pain management is really individualized, and it's encouraging that there's a lot of options these days.
Vandana Sharma, MD: There are several options at this point, and as the technology is emerging, even talking about the spinal cord stimulators, in the last 10 years, there has been such a tremendous change in how the different programming options are available, different kinds of IPG, the battery options available, rechargeable versus chargeable. Their sensitivity to MRIs has changed so much. In the past, we couldn't do MRIs on the patients who had neuromodulators in place, but nowadays most of these companies are making spinal cord stimulators that are MRI compatible.
So patients have several different things to choose from, and talking about the pain treatments per se, there are several advances in the technology as well as in the pain treatment options to help and offer to the patients as they need it, based on what kind of pain syndrome they have.
Host Amber Smith: Well, Dr. Sharma, thank you so much for taking time to share this information with us. I appreciate it.
Vandana Sharma, MD: Thank you for having me. It's my pleasure.
Host Amber Smith: My guest has been anesthesiologist Vandana Sharma, the director of Pain Management Services at Upstate. "The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe.
Find our archive of previous episodes at upstate.edu/informed. This is your host, Amber Smith, thanking you for listening.