A little background

Before we dive in, let’s talk about Deep Brain Stimulation (DBS) and batteries (also known as neurostimulators or impulse generators). In DBS surgery, leads, or thin wires, are implanted into brain areas that control movement. Typically, one lead is placed on each side of the brain. Sometimes, a person will have only one lead on one brain side or, occasionally, more than one lead on each side. Each brain wire controls the opposite side of the body — the left lead eases motor symptoms on the right side of the body and vice versa.

Following placement in the brain, leads are joined to extender, or connector, wires that are tunneled under the skin and attached to the battery. In the battery, each lead is inserted into a specific “channel.” The battery, which also controls the amount of electricity flowing through each wire, is usually placed below the collarbone. Your doctor programs specific settings for each lead, based on your symptoms and any side effects. (Read more about DBS.)

After a few years or more, the battery must be replaced. Exactly when that is depends on the specific device, whether the battery is rechargeable (those last longer), and your programming settings (higher settings drain the battery faster). Your doctor monitors battery strength and recommends replacement, when needed. In the replacement procedure, usually performed under general anesthesia, the old battery is removed and a new battery — sometimes updated, based on the latest technology — is placed in the same location and connected to the existing DBS leads. This typically takes less than an hour and you go home the same day.

Any surgery, hospital stay or other stress, such as infection, can temporarily worsen Parkinson’s symptoms. This procedure, although not as involved as initial DBS placement, is no exception.

The family’s story

A person with Parkinson’s, who had DBS surgery decades ago, had a routine battery replacement. His prior three battery replacements went smoothly, so he, understandably, thought this surgery would be no different. However following battery replacement, his symptoms suddenly and significantly increased. He was unable to move and fell several times. Unfortunately, his doctors mistakenly chalked the changes up to “older age” and progressing disease. But with strong and persistent advocacy by the person and his spouse/care partner, the problem was eventually discovered.

The problem: When the surgeon replaces the battery, the left DBS lead must be connected to the left channel and the right to the right channel within the battery. In this case the leads were accidentally swapped — the left lead connected to right channel and right lead to the left channel — which means the programmed settings were inadvertently swapped too. The right lead was operating with the left’s settings and vice versa. Once discovered, it was an easy fix — simply swap the program settings so the correct settings run through the correct lead. However, the delay in determining the problem and the challenges experienced prior to discovery were unfortunate and avoidable.

Battery replacement complications

Even though it’s a fairly minor procedure, battery replacement — or any procedure when living with Parkinson’s for that matter— should be taken seriously. Although complications don’t happen often, possibilities include:

• Lead swap: When the leads are attached to the new battery, they can, inadvertently, be plugged into the wrong channel. This can happen because the leads look the same, they are not marked left or right, and they travel closely together. To keep track during the procedure, a surgeon may tie a stitch around one or use another temporary marker. If the leads are connected incorrectly, the left lead settings are delivered through the right side and vice versa. This can cause increased symptoms. The key is catching the mix-up immediately, noting it in the medical chart, and communicating it to DBS providers and programmers and — most importantly — sharing with the patient and family. It’s easy to work around this issue by simply swapping programmed settings. (Some people also may wish to wear a medical alert bracelet or carry an ID card with this information.) But if it’s not recognized immediately, there can be challenges.
• Lead movement: A much less common possible adverse effect is movement of a wire within the brain. During battery replacement, the surgeon has to gently disconnect leads from the old battery and attach to the new one. If this movement is a little too strong — because of scar tissue or other challenges — the wire could move from its target in the brain. Because the location is so precise, even slight movement can cause less benefit and more symptoms. If this is a concern, your doctor will order a CT or MRI brain scan to confirm the leads are in place. They’ll also adjust settings to see if they can still control symptoms, even though a lead may be a little off target. If this is not successful, you may need to consider surgery to replace the lead.
• Overstimulation: When nearing the need for replacement, a battery gradually loses power. When this happens, your doctor might need to increase settings to get the right amount of stimulation to ease symptoms. When a new battery, with full power, is put in, you may experience too much stimulation. And this could cause involuntary movement (dyskinesia) or other side effects. If this happens, settings simply need to be turned down.
• Infection: There is a low risk of infection. But, it can occur, especially with multiple battery changes over time. Your doctors limit the risk with careful protocols in the operating room. And you can limit risk by keeping the skin wound clean and dry. If the skin becomes red, painful, swollen or warm; the incision oozes; or you have a fever, contact your doctor immediately. Infection is typically treated with intravenous (IV) antibiotics and only very rarely with removal of the battery.
• Bleeding: There is also potential for bleeding from the incision, especially if you have bleeding problems or take blood thinners. If this happens, contact your doctor right away. Most of the time, bleeding slows with pressure or special bandages, as directed by your doctor. But if it doesn’t, you may need additional treatment. Most of the time blood thinners, other than aspirin, are temporarily stopped for battery change operations. The recommendations for each person should be discussed with the surgeon and prescribing doctor.

What to know and do

The most important: Make sure you choose, if possible, a surgeon and center with a lot of DBS experience to replace your battery. It’s a seemingly simple procedure, but as you now know, complications can happen. How often varies from surgeon to surgeon and center to center. It’s typically less often among those with the most experience. At the same time, those that do the most DBS will see rarer complications simply by nature of the numbers.

If you do not have access to an experienced DBS center, it is important you choose a surgeon who has ample experience with these types of battery changes.

Ask your DBS doctors for a referral to a qualified surgeon. Ask others in the community for their recommendations, too. And ask your surgeon how long they’ve been doing the procedure, how often they do it, and what their personal complication rates are.

After the procedure, pay close attention to symptoms. Pain is common after battery changes. But if you have new weakness, numbness, or changes in talking or walking, you should seek medical attention immediately. And if you or your loved ones notice a significant difference in PD symptoms, talk with your doctor right away. It could be a temporary worsening due to the surgery, pain medication and other new factors. If that’s the case, you should, hopefully, see improvement in the days to weeks after. If you aren’t getting better or you’re much worse, ask whether you might have a complication and how you and your doctor can look for and remedy it, if so. Remember, you know yourself or your loved one best, and you are your own best advocate.

What we’re doing

Deep Brain Stimulation has come a long way since its initial approval nearly three decades ago. There are now several devices from three manufacturers, incorporating incremental innovations and technology upgrades. (Read about available devices.) Scientists are now working on the next generation of DBS devices — so called “closed loop” systems that can monitor one’s symptoms and deliver stimulation on demand. Research, like the MJFF-supported RAD-PD study, also aims to learn more about the “real world experience” of DBS — who gets the treatment, when, for what symptoms, where in the brain, with what device and with what side effects. This will help develop clearer guidelines and stronger recommendations for DBS care.

While future DBS systems (some with more than two leads) bring the promise of better and broader symptom control, longer battery life, and smaller devices, they can also bring more potential complications, like the one highlighted here. It’s critical that community members continue sharing their experiences — both good and bad — and MJFF amplifies these voices to educate people living with disease, their families and their clinicians.