A Stanford neurosurgeon answered questions about Deep Brain Stimulation

A Stanford neurosurgeon answered questions about Deep Brain Stimulation

Stanford’s Parkinson’s Community Outreach Program hosts a quarterly deep brain stimulation (DBS) support group meeting for those wanting to learn more about this surgical treatment for Parkinson’s disease (PD). The June 2020 meeting featured Dr. Daniel Kramer, a neurosurgeon and clinical instructor at Stanford, who answered audience questions pertaining to DBS. We at Stanford Parkinson’s Community Outreach viewed the discussion and are sharing our notes.

To protect privacy, we’ve not shared any of the audience’s names or specific medical history. The webinar was not recorded.

If you are interested in attending the Stanford DBS support group meeting, please contact the group coordinator, Steven Russell, swrussell@stanford.edu, to be added to the email reminder list.

With DBS, a surgically implanted medical device delivers controlled electrical stimulation to targeted areas of the brain, similar to a cardiac pacemaker. The goal is to reorganize the abnormal brain signals that cause disabling motor symptoms.  If you are interested in good informational resources about DBS, please check out our website.

To help decide if DBS is right for you, read about others’ DBS experiences.  Our website lists useful online stories.

Now… on to our notes from the meeting.

– Lauren

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A Stanford neurosurgeon answered questions about Deep Brain Stimulation – Meeting notes

Presented by Stanford Parkinson’s Community Outreach

June 18, 2020

Summary by Lauren Stroshane, Stanford Parkinson’s Community Outreach

Dr. Daniel Kramer is a neurosurgeon and clinical instructor who recently completed his fellowship in neurosurgery at Stanford. He will be moving to the University of Colorado, Anschutz to establish his surgical practice. He answered questions pertaining to Deep Brain Stimulation (DBS) surgery and living with DBS. The Q&A is organized into the following categories:

  1. Considering DBS
  2. Undergoing evaluation for DBS
  3. After DBS surgery
  4. Future directions for DBS

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Part 1: Considering DBS

Q: Are DBS surgeries happening again now at Stanford?

A: Yes, but the patient needs to have a negative Covid-19 test within 72 hours before they come in for the surgery.

Q: When in the PD disease process is a good time to consider DBS?

A: This is a great question and a subject of ongoing research. You don’t want to do it too early if medications are working well to control your PD symptoms. But considering DBS too late is a much more common problem. Sometimes people wait too long to get the surgery, and by the time they are ready to proceed, they have developed other illnesses – such as cardiovascular disease – that may increase their risks or even disqualify them from DBS surgery.

Q: What kinds of PD symptoms are helped by DBS?

A: DBS is wonderful for the motor symptoms of PD, such as tremor, slowed movement, and rigidity. Anything that your PD medications improve will likely also be improved with DBS therapy. It sometimes helps with gait, though it depends what your specific gait issues are.

Q: What kinds of PD symptoms aren’t helped by DBS?

A: The many non-motor symptoms of DBS are not usually helped by DBS. These include symptoms like constipation, depression, sleep issues, cognitive changes, and blood pressure fluctuations, among others.  Having realistic expectations and an honest discussion of your goals is essential before surgery. With your neurologist or neurosurgeon, make a list of your most bothersome symptoms and identify which ones are likely to be helped by DBS, and which ones are not.

Q: How much can people usually reduce their PD medications after DBS?

A: It varies a lot person-to-person, depending on what kind of benefit you receive from your medications and DBS, and what your most bothersome symptoms are. Most individuals can expect about a 50 to 60 percent reduction in PD medications after surgery.

Q: Are there people that can’t tolerate Sinemet who might still be a good candidate for DBS?

A: The usual feeling is that we like a DBS surgical candidate to have a good response to Sinemet – this is a strong indicator that they will respond well to DBS therapy. However, some people can’t tolerate Sinemet for various reasons, usually due to side effects such as low blood pressure or nausea. For those who don’t take Sinemet, this does not necessarily disqualify you. But we will still need to do a one-time trial of Sinemet that dissolves under the tongue to show that you have a response.

If you have a lot of tremor that generally doesn’t respond to medication, it should still respond well to DBS. Dyskinesias tend to respond very well too.

Q: Does DBS help for those with PD who have a lot of dystonia, in the toes and feet?

A: Yes! DBS is performed for generalized dystonia as well as for PD. It is important to consider when your dystonia tends to occur; is it when your meds are kicking in or wearing off? Or does it happen regardless of your medication schedule?

If your dystonia seems to occur in relation to your medication schedule, then DBS will likely help because it smooths out the motor fluctuations that occur on medication. If your dystonia seems to have no relation to your medications, then it will be harder to predict if DBS will help with this symptom.

Q: Is there any downside to implanting DBS early?

A: None that Dr. Kramer knows of. On the contrary, it is much more common that people wait too long. He suspects that within 5 years, we may have some studies showing that earlier is better. All the risk of DBS is up front, particularly with rechargeable batteries that don’t need to be changed for a decade or more; once the surgery is done and healing has finished, the long-term risks of infection or other complications are extremely low.  

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Part 2: Undergoing evaluation for DBS

Q: What is the process of getting approved for surgery?

A: Evaluation and approval for DBS is a multidisciplinary process, incorporating your neurologist, a neuropsychologist, and the neurosurgeon. The goals of evaluating patients are to determine what benefits the patient can expect from the surgery, confirm the diagnosis of PD, and assess their risk of possible complications. It is really important to make sure you actually have PD, not an atypical parkinsonism or something else that can mimic PD but would not be benefitted by DBS.

Each surgical center does things a little differently, but typically once you have been referred for DBS evaluation, you would have an in-person exam both on medication and off medication to compare your PD symptoms in each state. These on/off exams may happen on the same day or on two consecutive days, depending on where you go. You will also need to undergo a battery of cognitive tests with a neuropsychologist. Again, this is an important part of the process in determining your risks from the surgery. Sometimes you may undergo brain imaging as well.

Once your evaluation appointments are complete, typically there is a meeting of the multidisciplinary team to discuss your case and see if there is consensus about whether the surgery is likely to be beneficial for you.

Q: Can some of the evaluation process now occur over telemedicine?

A: Some of the evaluation needs to be in person – the physical exam, for instance – but the conversation with the surgeon can occur virtually.

Q: How do you, as a surgeon, decide on the best placement in the brain for the DBS leads?

A: It’s surgeon preference, and it varies person to person. Some surgical centers tend to do more of one brain target than the other. The main DBS targets for people with PD are the sub-thalamic nucleus (STN) and the globus pallidus interna (GPi). Studies suggest there may be slight differences between the sites but our evidence is not conclusive yet.

For those who have really severe dyskinesias triggered by medication, sometimes STN is better for that because one can typically reduce medications a lot. For those who have dyskinesias that seem less clearly correlated with meds, GPi may be preferable.

Q: It seems like there are several different brands of equipment for DBS. What brands does Stanford implant?

A: The Stanford neurosurgeons typically implant either Medtronic or Boston Scientific DBS. Theoretically, they could do the Abbott device as well, but as far as Dr. Kramer knows, they don’t currently implant that model. For a rechargeable battery and directional lead, Boston Scientific is best. But there are advantages to both types of DBS systems, it just depends on what you’re looking for. Medtronic is coming out with a sensing electrode for closed-loop stimulation in the future, that can respond to your activity.

Q: Does Stanford do awake or asleep surgeries?

A: The neurosurgeons at Stanford can do both, depending on the needs of the patient. The results are usually the same, but there are details of the patient experience in either case that you should discuss with your surgeon if you are considering DBS.

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Part 3: After DBS surgery

Q: What happens if someone who has DBS then catches Covid-19?

A: Do you mean right after surgery, or in the long term? In the near term after surgery, we are most worried about a bacterial infection, not a viral infection. With Covid-19, it’s usually just the coronavirus, not a concurrent bacterial infection. Of course, anytime you go through the stress of surgery, this puts you at slightly higher risk of getting sick due to the additional strain on your immune system.

If you are undergoing DBS surgery during the Covid-19 pandemic, you should be strict after the surgery in terms of social distancing and protecting yourself from potential sources of exposure. Everyone who undergoes DBS will need help from a loved one for a few days or weeks after the surgery; it’s also important that whoever is caring for you is also being careful about Covid-19 exposure.

Q: If there’s an infection at the stimulator in the chest, can the infection travel up the wires into the brain?

A: Yes, but this is extremely rare. There is about a 2-5% infection rate after surgery, depending on the center you go to. If you get an infection, it is nearly always at the battery site in the chest, and typically you would notice changes in the skin or color of the area. To travel all the way up the wire to the brain, it would have to be a really severe infection that would take days or weeks to develop. It would be surprising for the individual not to notice the infection and contact their doctor before it got to that point.

Q: With the different systems that are being implanted, are there different rules for getting an MRI depending what system you have?

A: All of them have some degree of conditionality for getting an MRI. It is fairly detailed, depending on the specific battery and lead that you have. For the most part, you can get an MRI with all of the systems. But sometimes people end up with a mixed system – for instance, Medtronic leads in the brain but Boston Scientific stimulator in the chest – which is more complex.

For someone who has a reason to get regular MRIs, make sure to keep your system consistent (all one brand) and discuss this with your neurosurgeon ahead of time.

Q: Is Medtronic the only one approved for dystonia?

A: There’s no reason that you shouldn’t be able to have benefit from the other devices for dystonia as well. Even though the Medtronic DBS is the only one officially approved for dystonia, the others are fine for this purpose as well. DBS for essential tremor is actually not approved for bilateral use, yet we do it commonly as “off label”. There’s no incentive for Boston Scientific and Abbott to do the trials necessary to get approved for dystonia, which is why they haven’t pursued this.

Q: How do I know when I need to get my battery changed?

A: Whenever you go for a programming “tune-up”, your neurologist should check your battery.  

You can also check it yourself at any time with your patient programmer remote. The neurologist can show you if you aren’t sure how.

Q: Can DBS start out great and gradually decline over time?

A: Remember, this is a treatment for PD symptoms, not a cure for the disease itself. The disease will continue to progress over time. Having 20 good years with DBS is what we expect; as the non-motor symptoms of PD continue to worsen, they usually become more troublesome than the motor symptoms that DBS will continue to treat.

Q: What is Stanford’s position on whether patients have to take antibiotics before routine dental procedures?

A: In the past, we told all our patients to do this. More recently, it has become clear we don’t have sufficient evidence to recommend it, so we no longer tell our patients they have to take antibiotics before routine dental work.

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Part 4: Future directions for DBS

Q: I’ve heard that closed-loop DBS will allow the DBS stimulation to respond and adjust to one’s daily activities, tailoring the therapy according to what one is doing. When will it be available?

A:  Yes, this is an exciting area of research right now. He would bet that within 5 years, this will be an option for patients. Dr. Helen Bronte-Stewart at Stanford is researching closed-loop DBS.

Q: With the changes from the new DBS systems, is now a good time for DBS or should I hold out for whatever new models will come?

A: It’s a great time for surgery! We can always switch the battery out if something new and exciting comes along; this is a much less invasive process than changing the leads in the brain, which typically remain there forever.