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The #1 Reason DBS Can “Fail” Even When the Surgery Technically Went Fine · Tremor & Parkinson's Surgery Explained with Dr. Wu

• 0:00
  SPEAKER_00: Sometimes a deep brain stimulation surgery or DBS can go completely smoothly.
• 0:05
  SPEAKER_00: There's no bleeding, there's no infection, device turns on, the patient recovers normally, and a few months later they're still saying, DBS didn't work for me.
• 0:14
  SPEAKER_00: Now, how can both of these things be true?
• 0:17
  SPEAKER_00: I'm Dr.
• 0:17
  SPEAKER_00: Chen Yanbu, and I'm a neurosurgeon specializing in DBS for Parkinson's disease and other movement disorders.
• 0:23
  SPEAKER_00: And one of the biggest reasons is something the patient usually never sees during the operation.
• 0:28
  SPEAKER_00: Exactly where the electrode ended up.
• 0:30
  SPEAKER_00: Because with DBS, a few millimeters can make a very real difference.
• 0:35
  SPEAKER_00: The target that we are aiming for is extraordinarily small.
• 0:39
  SPEAKER_00: D-brain stimulation works by placing an electrode into a very specific part of the brain and using electrical stimulation to affect the circuits involved in movement.
• 0:48
  SPEAKER_00: But these are not large targets.
• 0:50
  SPEAKER_00: We're working in areas where moving only a millimeter or two can put the electrode closer to a different structure or different group of nerve fibers.
• 0:58
  SPEAKER_00: So there really isn't much room for error.
• 1:01
  SPEAKER_00: And that matters because the stimulation can only have an effect on a small amount of brain around the electrode.
• 1:07
  SPEAKER_00: If it is too far from the ideal target, it may not work in the way we expect it should.
• 1:12
  SPEAKER_00: So you can have an operation with no technical complications at all.
• 1:16
  SPEAKER_00: But if the electrode is not ideally positioned, we may have trouble getting enough stimulation into the area we want without also stimulating something that causes side effects nearby.
• 1:26
  SPEAKER_00: Now, that can show up in a few different ways.
• 1:28
  SPEAKER_00: We may get some improvement, but not as much as we expected.
• 1:31
  SPEAKER_00: One symptom may get better, but side effects start showing up when we try to increase the stimulation.
• 1:37
  SPEAKER_00: Or the patient may simply never get the kind of benefit everyone expected going into the surgery.
• 1:42
  SPEAKER_00: At that point, people understandably start saying DBS failed.
• 1:47
  SPEAKER_00: So before I conclude that DBS itself failed, I want to know something much more basic.
• 1:52
  SPEAKER_00: Where exactly was the electrode implanted?
• 1:56
  SPEAKER_00: Because this is the most important detail when it comes to figuring out what is actually going on.
• 2:00
  SPEAKER_00: Fortunately, sometimes we can simply fix the problem by changing the settings of the stimulator.
• 2:06
  SPEAKER_00: And sometimes we cannot.
• 2:08
  SPEAKER_00: Programming is the process of finding the best settings for the stimulator, and it's a huge part of DBS.
• 2:14
  SPEAKER_00: We can change the specific location on the electrode we use, how much stimulation we deliver, and other settings to try to improve symptoms while minimizing side effects at the same time.
• 2:24
  SPEAKER_00: With newer directional electrodes or what may be referred to as segmented electrodes, we have even more ability to shape where that stimulation goes.
• 2:32
  SPEAKER_00: The way I think about that is instead of turning on a lamp and having a light shine all directions equally, a directional electrode acts more like a flashlight, which allows us to shine the stimulation more in one direction or another.
• 2:44
  SPEAKER_00: So directional electrodes allow us to compensate more for electrode location than older omnidirectional electrodes.
• 2:51
  SPEAKER_00: But there is still a limit to what programming can compensate for.
• 2:55
  SPEAKER_00: If the electrode is sitting a little too far away from the area we really want to stimulate, one option is to increase the stimulation and make the electrical field larger.
• 3:05
  SPEAKER_00: The problem is that as that field gets larger, it may start having an effect on other nearby structures, areas that we don't want to be stimulating, areas that cause side effects.
• 3:14
  SPEAKER_00: And when that happens, the patient might get tingling, muscle tightness, speech changes, balance problems, or another side effect before we ever get enough stimulation to the area that we're actually trying to target.
• 3:26
  SPEAKER_00: So the device may be working exactly as it was designed to do, but we still can't get enough stimulation into the right place without running into the side effects first.
• 3:35
  SPEAKER_00: And that is why electrodocation matters so much.
• 3:38
  SPEAKER_00: Programming gives us flexibility, but it does not give us unlimited ability to overcome poor electrode placement.
• 3:45
  SPEAKER_00: These details are really specific to each and every patient.
• 3:48
  SPEAKER_00: So if you're dealing with Parkinson's and wondering whether DBS might be right for you or already have DBS and you're not getting the result that you expected, you may want to be evaluated by an experienced team.
• 3:59
  SPEAKER_00: And if you happen to be in my area, you can find information from my office in the description below.
• 4:03
  SPEAKER_00: Also, if this kind of explanation is helpful, subscribe to the channel.
• 4:06
  SPEAKER_00: I make these videos to help patients understand what actually matters before, during, and after surgery for movement disorders.
• 4:13
  SPEAKER_00: Now, if electrode location matters this much, the next question is obvious.
• 4:17
  SPEAKER_00: How do we know where it actually ended up?
• 4:19
  SPEAKER_00: Now, before surgery, we use detailed imaging to identify the target and plan the path we want the electrode to follow.
• 4:26
  SPEAKER_00: That planning is extremely important, but planning where you want the electrode to go and confirming where it actually went are two different things.
• 4:34
  SPEAKER_00: Now, there are different ways surgeons try to gather information about whether the electrode is where we want it.
• 4:39
  SPEAKER_00: Some surgeons record the activity of individual brain cells or neurons during the operation.
• 4:45
  SPEAKER_00: You may have heard the term microelectrode recordings when it comes to this approach.
• 4:48
  SPEAKER_00: Some perform stimulation testing while the patient is awake.
• 4:51
  SPEAKER_00: Others can look at responses to stimulation while the patient is still asleep under anesthesia.
• 4:57
  SPEAKER_00: Some, like myself, rely more heavily on detailed imaging that we get in the operating room.
• 5:02
  SPEAKER_00: And newer technology continues to give us additional information about the brain activity around the electrode.
• 5:07
  SPEAKER_00: So you can see that there are many ways to gather information about whether the electrode is where we want it.
• 5:12
  SPEAKER_00: And I don't think we should be dogmatic about one technique and say this is the only way that we should be doing DBS, this is the right way, and every other way is wrong.
• 5:21
  SPEAKER_00: These methods all give us different pieces of information, and none of them is perfect by itself.
• 5:26
  SPEAKER_00: So the way I think about it is that I want to use all the reliable information available to me to make the best decision I can for the individual patient.
• 5:34
  SPEAKER_00: In my practice, my patients are asleep under general anesthesia, and imaging plays a major role in the surgical process.
• 5:41
  SPEAKER_00: I use robotic guidance to help me follow the trajectory that we planned.
• 5:45
  SPEAKER_00: And on that note, since some people ask, the robot is not choosing the target for me.
• 5:50
  SPEAKER_00: It's not actually doing the surgery.
• 5:51
  SPEAKER_00: The robot is not a human-like device.
• 5:54
  SPEAKER_00: I'm choosing the target and planning the path.
• 5:57
  SPEAKER_00: The robot looks more like an industrial arm that helps me reproduce that plan very precisely in the operating room and holds the trajectory in a very accurate way.
• 6:06
  SPEAKER_00: Now, depending on the specific situation, I may use microelectro recordings or MER.
• 6:11
  SPEAKER_00: I may also test the stimulation after the electrode has been implanted and look for responses using recording equipment we temporarily place on the face, the arms, or legs during surgery.
• 6:21
  SPEAKER_00: But what I do every time on top of all of that is verify the final electrode location with imaging in the operating room.
• 6:29
  SPEAKER_00: That part is important to me because I don't want to finish the operation by just assuming the electrode must be where I intended just because everything seemed to go smoothly.
• 6:38
  SPEAKER_00: I want to see it with my own eyes.
• 6:39
  SPEAKER_00: Seeing is believing.
• 6:40
  SPEAKER_00: I want to see where it actually went.
• 6:42
  SPEAKER_00: And if the information we have tells me that the electrode is not where I want it, I would rather make that decision while we are still in the operating room than discover it months later when someone isn't getting the benefit we expected.
• 6:53
  SPEAKER_00: In reality, a millimeter or two sounds insignificant until you're working in part of the brain where those couple of millimeters can change which structures you end up stimulating.
• 7:03
  SPEAKER_00: And wherever we leave that electrode is ultimately what the programming team has to work with afterwards.
• 7:08
  SPEAKER_00: Now, I've made a big deal about electrodepositioning, but in truth, not every disappointing result is a placement problem.
• 7:14
  SPEAKER_00: Because as a surgeon, I'm likely a little biased in terms of what I see as the cause of ineffective DBS.
• 7:21
  SPEAKER_00: But in reality, electrodeposition is not the explanation for every disappointing DBS result.
• 7:26
  SPEAKER_00: I realize that, and it is important that you do as well.
• 7:29
  SPEAKER_00: Sometimes it is a matter of programming.
• 7:31
  SPEAKER_00: There's good evidence that experienced reprogramming can substantially improve outcomes in some patients.
• 7:36
  SPEAKER_00: And finding the right electrical prescription for stimulation can make a big difference in the efficacy of DBS.
• 7:42
  SPEAKER_00: Unfortunately, sometimes the reason DBS is not working is not so straightforward.
• 7:46
  SPEAKER_00: The patient may not have been an ideal candidate or the symptom they wanted to improve may not respond well to stimulation.
• 7:52
  SPEAKER_00: These are reasons why careful evaluation of the symptoms before surgery and more importantly a discussion of the main goals and expectations of the surgery are so important in the decision to move forward with DBS.
• 8:04
  SPEAKER_00: Now, yet another possibility is that there may be an issue with the hardware itself.
• 8:08
  SPEAKER_00: Hardware failures are fortunately becoming less common as devices have improved over time, but we do see issues crop up every now and then.
• 8:16
  SPEAKER_00: Also, since Parkinson's continues to change over time, patients may develop symptoms that stimulation was never expected to control.
• 8:24
  SPEAKER_00: So I don't want to create the impression that every patient who isn't doing well after DBS simply has an electrode in the wrong place.
• 8:31
  SPEAKER_00: They don't.
• 8:31
  SPEAKER_00: But electrode location is one of the major things that we, as in me and my neurosurgical colleagues, can actually control during the operation.
• 8:40
  SPEAKER_00: And if that part is wrong, everything afterward becomes more challenging.
• 8:43
  SPEAKER_00: That's why it's important not to think of accurate electrode placement only as a minor technical detail because it directly affects what the programming team can do with the device after surgery.
• 8:54
  SPEAKER_00: So what does good placement ultimately give us?
• 8:56
  SPEAKER_00: The goal is not simply to get the electrode somewhere inside the target.
• 9:00
  SPEAKER_00: I want it positioned in a way that gives the programming team room to work.
• 9:04
  SPEAKER_00: We call that the therapeutic window.
• 9:06
  SPEAKER_00: That is the amount of room we have between the dose of stimulation where we first see symptoms improve and before we start producing side effects.
• 9:14
  SPEAKER_00: Good placement generally gives us more options when we're programming the device later.
• 9:18
  SPEAKER_00: And that flexibility is particularly important in Parkinson's because the disease and the patient needs continue to change over time.
• 9:26
  SPEAKER_00: So you can see that the operation is really only the beginning of DBS.
• 9:30
  SPEAKER_00: The surgery puts the hardware in place.
• 9:32
  SPEAKER_00: Whatever position we leave that electrode in is what the programming team has to work with afterward.
• 9:37
  SPEAKER_00: Now, what if someone already has DBS and it isn't working the way they want?
• 9:42
  SPEAKER_00: If someone comes to me and says, I had DBS and it never really worked, I would not automatically assume there is nothing else to do.
• 9:49
  SPEAKER_00: We need to work through the possibilities.
• 9:51
  SPEAKER_00: First, I want to understand what they were trying to treat.
• 9:54
  SPEAKER_00: What was their goal of DBS surgery?
• 9:56
  SPEAKER_00: And were they really a good candidate for DBS?
• 9:58
  SPEAKER_00: Were the symptoms they were hoping to improve actually symptoms that should respond to stimulation?
• 10:03
  SPEAKER_00: Then I want to know what happened during programming.
• 10:06
  SPEAKER_00: Which settings have been tried?
• 10:07
  SPEAKER_00: Did any contacts work better than others?
• 10:10
  SPEAKER_00: What happens when stimulation is increased?
• 10:12
  SPEAKER_00: Do side effects appear before we get enough benefit?
• 10:15
  SPEAKER_00: We also have to make sure the hardware itself is functioning properly.
• 10:19
  SPEAKER_00: And of course, I want to look at the imaging myself and ask that same basic question again.
• 10:24
  SPEAKER_00: Where are the electrodes?
• 10:25
  SPEAKER_00: Because sometimes patients spend months or even years trying different settings when the main limitation is the electrode and where it is sitting in the brain.
• 10:34
  SPEAKER_00: If it is too far away from the intended target, there may be simply only so much the programming team can do.
• 10:40
  SPEAKER_00: And that is so important in understanding what problem we're actually dealing with.
• 10:44
  SPEAKER_00: Now, what happens if we discover a misplaced electrode?
• 10:48
  SPEAKER_00: Sometimes we can fix it.
• 10:49
  SPEAKER_00: If someone is getting very little benefit, we've done appropriate programming, the symptoms should reasonably respond to DBS, and imaging shows that the electrode location is likely the limiting result.
• 10:59
  SPEAKER_00: If someone is getting very little benefit, we've done appropriate programming, the symptoms should reasonably respond to DBS, and the imaging is what shows us that the electrode location is what is likely limiting the result, then revision surgery may be worth discussing.
• 11:14
  SPEAKER_00: And that can mean repositioning or replacing the electrode in the brain.
• 11:18
  SPEAKER_00: Obviously, nobody wants to go through another brain operation unless there is a very good reason.
• 11:22
  SPEAKER_00: So before I recommend that, I want to be confident that moving the electrode gives us a reasonable chance of improving the outcome.
• 11:29
  SPEAKER_00: And again, this comes back to using all the information we have rather than making a decision based on any one piece of information alone.
• 11:37
  SPEAKER_00: The symptoms matter, the programming response matters, the imaging matters.
• 11:40
  SPEAKER_00: We put those things together and try to make the best decision for that particular patient.
• 11:45
  SPEAKER_00: And it is also why I put so much emphasis on accuracy in the first place.
• 11:50
  SPEAKER_00: The goal is to give the patient the best chance of getting a good result without ever needing to have that conversation, without ever needing to consider revision surgery.
• 11:58
  SPEAKER_00: So unfortunately, just because the surgery went well doesn't always mean that the DBS will work perfectly.
• 12:04
  SPEAKER_00: This is the distinction I want patients to understand.
• 12:06
  SPEAKER_00: When a surgeon says the operation went well, they generally mean there was no bleeding, no infection, no unexpected complication, and the patient recovered normally.
• 12:15
  SPEAKER_00: Those are obviously important, but with DBS, there's another question that matters just as much.
• 12:20
  SPEAKER_00: Did we put the electrode in a location that allows us to get the benefit we are aiming for?
• 12:25
  SPEAKER_00: Because what is most important to those undergoing DBS is whether their tremor or stiffness or slowness or fluctuations and symptoms ultimately will get better.
• 12:34
  SPEAKER_00: They care whether they can move more easily and whether they can get through more of the day without waiting for that medication to kick back in.
• 12:41
  SPEAKER_00: So if you have had DBS and the result was disappointing, I would not automatically conclude that deep brain stimulation simply does not work and that it won't work for anybody else.
• 12:50
  SPEAKER_00: Sometimes the symptom was never a good target for DBS.
• 12:53
  SPEAKER_00: Sometimes the programming needs more work.
• 12:55
  SPEAKER_00: Sometimes there's a hardware problem, and sometimes we need to go back and look exactly at where the electrode is implanted in the brain.
• 13:03
  SPEAKER_00: The important thing is figuring out which of those explanations actually applies to you because the surgery went well and the DBS worked well are not always the same thing.
• 13:13
  SPEAKER_00: If you're considering DBS and you want to see how I try to reduce that risk during surgery, watch my video on modern Parkinson's brain surgery next.
• 13:21
  SPEAKER_00: That's where I walk through how I use imaging, robotic guidance, and verification when I place these electrodes.
• 13:27
  SPEAKER_00: Until next time, bye bye.