A surprising fact about deep brain stimulation (DBS) surgery technology is that human DBS leads (the wire implanted in the brain and connected to the neurostimulator) and their four shiny, tiny contacts have not really changed much over the last two decades. One reason for the durability of DBS lead design has been the long-term beneficial effects of using this simple approach.
However, there are compelling reasons to introduce new DBS lead designs into clinical practice. Each target in the brain is a different size, therefore the volume of electricity that reaches that target should be tailored to the appropriate region. Additionally, there are structures and connecting pipes (fibers) that require selective activation in order to function optimally. Placing DBS leads accurately is not an easy task and the ability to steer the electrical current may enhance benefits and reduce stimulation-induced side effects.
Several companies have introduced different versions of DBS leads capable of better steering and shaping the current to targets in the brain. In October 2016, St. Jude Medical was the first to market with a U.S. Food and Drug Administration approved segmented DBS lead (named the Infinity™ DBS system ) that is capable of electrical current steering, which means that this lead has four small contacts (known as a segmented lead), two of them splitting into three zones each. The zones on each contact point can be activated or deactivated to steer current, improve outcomes and to potentially reduce complications. Ongoing studies will soon help us understand the benefits of this new approach.
Boston Scientific also has a new lead, the Vercise™ implantable pulse generator (8-contact lead, Natick, MA) in that is capable of simultaneously activating multiple areas and allowing the physician or DBS programmer to choose the percentage of electrical current delivered at each contact on the DBS lead. This DBS lead design was recently tested by Lars Timmermann and his colleagues in Germany.
There are twice as many contact points to stimulate on the new lead design: eight as opposed to the standard four. Eight contacts with the ability to turn on one, several or all of the contacts (multiple source) and shape the size of the current at each contact point offers the possibility of an enhanced benefit-to-side-effect ratio. These potential benefits will need to be demonstrated in formal studies. The downside is that this approach may complicate programming the device in a community setting for general neurologists. Also, the battery life of this device may quickly deplete since it uses multiple sources of electrical current. The company addressed these issues by making the device rechargeable and providing a user-friendly programming platform. The system is now part of an ongoing clinical trial.
Aleva Nanotherapeutics has a similar current-steering, but novel lead design. Dr. Claudio Pollo in Bern, Switzerland, tested this new DBS lead design. Pollo and his colleagues examined shaping the DBS current by sending it in three different directions in the brain and comparing these new shapes of stimulation to standard paradigms used in commercially available devices. In the original Aleva study, every patient except one showed a superior benefit favoring the newer lead with directional steering of the electrical current. Researchers also reported the therapeutic benefit could be achieved by using less than half of the energy, thereby reducing battery drain. This lead is being developed as a stand-alone product that could one day be used with different battery sources.
Recently, a third company also introduced a new DBS lead design: Sapiens SBS, now owned by Medtronic, Minneapolis, MN. The new Dutch DBS lead is unique in that it has 40 small circles (the active DBS contacts) that spread over a large span of the DBS lead. When I first saw this technology about five years ago I dubbed it “the leopard” because the lead had multiple spots and you could change, activate and deactivate the spots to customize, shape and steer the DBS current. The company is developing an easy-to-use interface to customize and deliver the stimulation. The lead has been successfully tested in monkeys by Jerry Vitek at the University of Minnesota and in humans by Hubert Martens and a team of doctors from Germany.
Advances in DBS technology will hopefully improve outcomes for people with Parkinson’s and also other patients who choose a bionic approach for symptomatic treatment. Each year, the DBS Think Tank reviews, discusses and summarizes all of the new DBS technologies. The most recent summary can be read at: http://journal.frontiersin.org/article/10.3389/fnins.2016.00119/full
1: Okun MS. 10 Breakthrough Therapies for Parkinson’s Disease. Books4Patients, 2015. The above excerpts from the book have been provided with permission from the author and publisher.
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You can find out more about the Parkinson's Foundation National Medical Director, Dr. Michael S. Okun, by also visiting the Center of Excellence, University of Florida Health Center for Movement Disorders and Neurorestoration. Dr. Okun is also the author of the Amazon #1 Parkinson's Best Seller 10 Secrets to a Happier Life and 10 Breakthrough Therapies for Parkinson's Disease. You can read more from Dr. Okun in the What's Hot in PD? archives.