Dr. Snyder, a functional neurosurgeon with Neurological Surgery, P.C., leverages neuromodulation techniques to improve the lives and outcomes of patients living with movement disorders.
Brian J. Snyder, MD, reviews the postoperative location of DBS electrodes in a patient with PD.
Neurological disorders, including developmental, neurodegenerative and psychiatric conditions, account for a large burden in human suffering and cost, according to the World Health Organization. The National Institutes of Health identifies more than 600 neurologic diseases, many of which are chronic and characterized by severely disabling symptoms.
In the quest to relieve some of the burden of these disorders and enhance patients’ quality of life, neurosurgery has evolved into a multidisciplinary approach encompassing the prevention, diagnosis, treatment and rehabilitation of neurological conditions, and has benefited from the emergence of various innovative solutions. Equipped with leading-edge technologies and techniques that rely less on large incisions than in previous years, surgeons can perform invasive yet delicate procedures within the brain and spine to treat complex disorders affecting the nervous system, including but not limited to epilepsy, intractable pain, a variety of movement disorders and psychiatric illness.
Functional neurosurgery is focused on the treatment of disease that may or may not have anatomic abnormalities but where the primary pathology is abnormal nerve behavior.
“My primary focus is the treatment of neurological conditions that frequently are not anatomically correctable abnormalities, but rather physiologic abnormalities that haven’t responded well or at all to anatomic surgery or other mainstay treatments,” Dr. Snyder explains. “Movement disorders, essential tremor, dystonia, Parkinson’s disease (PD) and other movement disorders, however, are diseases of neurocircuitry. In properly selected patients, these diseases can be treated well with neuromodulation.”
Dr. Snyder approaches these physiologic, or functional, challenges — namely, in patients living with epilepsy, chronic or intractable pain, movement disorders like dystonia, PD and tremors, and psychiatric illness — with a range of revolutionary, life-changing interventions.
Successful Treatment for Motor Refractory Symptoms of PD
PD develops when dopamine production ceases in a specific region of the brain, leading to a loss of controlled movements. Marked by muscle tremors and rigidity, diminished mobility, poor balance and coordination, and slow voluntary movements, PD affects as many as 1 million Americans — more than those diagnosed with multiple sclerosis, muscular dystrophy and Lou Gehrig’s disease combined, according to the Parkinson’s Disease Foundation. These statistics, though, don’t tell the whole story.
A diagnosis is made based on patients’ medical histories and neurological exams. Each year, approximately 60,000 Americans are diagnosed with PD. However, because PD is a progressive disease and the majority of people with the condition do not develop symptoms for years, there is no lab test for PD.
“Functional neuromodulation therapies should be considered when best, first-line medical therapies have failed or only provide suboptimal control of a disease or its symptoms.”
— Brian J. Snyder, MD, functional neurosurgeon at Neurological Surgery, P.C.
Dr. Snyder reviews intrathecal pump implantation with a patient.
A physician’s chief goal is to alleviate symptoms, which are often highly debilitating, especially as the disease progresses. First-line treatment for PD is medication therapy. However, as Dr. Snyder notes, medical therapy frequently fails to provide optimal symptom control.
PD medications often stop being effective, or patients develop dyskinesia — abnormal, involuntary, sometimes debilitating movements that are the result of dopamine-replacement therapy — or bradykinesia, progressive slowness of motion.
Still, there is hope for patients for whom medication therapy alone is not successful. Dr. Snyder explains that PD patients who are no longer experiencing adequate results from medication therapy are often ideal candidates for deep brain stimulation (DBS), a procedure he’s an expert in performing and that he was the first in Long Island to implement.
“DBS involves placing electrodes into one or both sides of the brain to treat symptoms on the contralateral side of the body,” Dr. Snyder says. “In essential tremor, for example, which may be a unilateral disease, we may operate on the left side for the right hand, which is the most typical scenario. PD, however, typically has bilateral features so we usually operate on both sides of the brain, as we typically do for dystonia, as well. DBS enables us to modulate the brain’s faulty signals by essentially blocking these malfunctioning signals that cause symptoms.”
There is no rush to the operating room. The patient selection process involves a team approach of community neurosurgeons and patients’ primary care providers agreeing on the patient’s diagnosis and then agreeing that the best medical management has failed the patient.
“In some cases, the movement disorder neurologist on the team may want to try another medication before trying DBS,” Dr. Snyder says. However, if medication management has been ineffective and the patient is living with disabling motor symptoms, DBS is considered.
The patient is sent to a neuropsychologist for an evaluation to ensure cognition is appropriate before Dr. Snyder and his team offer DBS as an option.
The procedure is performed in a highly specific manner. First, the patient is placed in a stereotactic head frame to undergo a CT scan, which is then fused with the previous MRI to provide Dr. Snyder with utmost accuracy for determining the best region in which to place the electrodes. The patient is awake during the procedure to take part in microelectrode recording, often performing tasks or experiencing tremors while Dr. Snyder records the concurring firing pattern of the cells associated with these activities. In some cases, he prompts the cells with a minute surge of electricity via the electrodes to observe the patient’s response. This additional information helps Dr. Snyder decipher whether he is in the precise area of the brain needing stimulation or needs to adjust his trajectory and the placement of the electrodes.
Once Dr. Snyder has identified the appropriate location, he permanently secures the DBS electrode. The electrode relies on a connection to a battery, which, similar to a cardiac pacemaker, is placed in the chest wall one week after implanting the electrode. Most DBS patients are able to return home the day after the surgery.
DBS has been shown to considerably reduce motor symptoms in people living with PD, as well as enable many patients to reduce their medications. While the amount of reduction varies, DBS is an effective therapy for many PD patients and can lead to a significant improvement in side effects such as dyskinesia.
Blocking Pain Pathways
Chronic pain, a condition affecting approximately 50 million Americans, according to a 2015 report from the National Institutes of Health’s National Center for Complementary and Integrative Health, is another chief condition Dr. Snyder commonly treats. Each year in the U.S., the burden of treating chronic pain — which includes the financial burden of pain care and the economic consequences of missed days of work, lost wages and productivity — costs society $560 to $635 billion. Dr. Snyder surgically treats chronic pain stemming from various causes, including atypical facial pain, cancer pain, failed back syndrome, spinal cord injury, spine surgery and trauma, among others.
Dr. Snyder and Gad Klein, PhD, discuss surgery on their patient with epilepsy.
The use of neuromodulation for the treatment of pain has gained increasing popularity for its safety, efficacy and minimal side effects.
“Historically, when employing neurostimulation for the treatment of pain, we relied on paresthesias — that is, the patient needed to feel some sort of tingling or buzzing from a neurostimulator device implanted in the body — and the device and process were intended to mask the pain,” Dr. Snyder says. “However, in the past five years, our field has seen the advent of exciting new devices and techniques — such as high-frequency (HF) SCS and dorsal root ganglion (DRG) stimulation — that don’t require the patients to feel stimulation, and, furthermore, have the potential to mask the pain even better.”
A 2015 Neurosurgery study showed that 76.5 percent of patients with back pain using the Senza system, a HF SCS system approved by the FDA in May 2015, experienced substantial, lasting pain relief, compared with 49.3 percent of those having low-frequency stimulation. Moreover, about 73 percent of patients with leg pain reported significant pain reduction, compared to almost 49 percent of those undergoing low-frequency stimulation.
DRG stimulation, another advanced pain treatment that recently became available, is an additional therapy Dr. Snyder employs for the treatment of chronic pain. By electrically stimulating the DRG, which plays an integral role in the regulation of chronic neuropathic pain, via electrodes connected to the brain, Dr. Snyder is able to modulate neuropathic pain signals. DRG neuromodulation can even be used for treating pain that hasn’t responded well to traditional SCS, such as pain in the hand, chest, abdomen, foot, knee and groin, according to the International Neuromodulation Society. However, DRG is also an effective means of interfering with pain associated with spine surgery, hernia surgery and complex regional pain syndrome (CRPS), among others, Dr. Snyder notes. For instance, a December 2016 Pain study showed that 81 percent of patients with complex regional pain syndrome or causalgia in the lower extremities undergoing DRG stimulation enjoyed at least a 50-percent reduction in pain, compared to an almost 56 percent of patients who had conventional SCS.
“Between HF SCS and DRG, it’s a new frontier for neurostimulation therapy for pain,” Dr. Snyder says. “Both of these modalities are revolutionary pain-relieving therapies.”
Pumping Symptoms Away
Neuromodulation by way of an intrathecal pump is another innovative treatment frequently employed by Dr. Snyder for pain. An intrathecal pump consists of a catheter and a device that deliver liquid pain medication into the affected area of the spine.
“We implant a large number of intrathecal pumps, mostly with baclofen, for patients who have multiple sclerosis, spinal cord injury, cerebral palsy and pain associated with stroke,” Dr. Snyder says. “For these patients, intrathecal pumps can be miraculous because the device allows for continuous infusion of a low dose of baclofen — which can be titrated to exactly the right dose — to optimize a patient’s spasticity.”
Dr. Snyder discusses upcoming surgical cases with his assistant, Michelle Barrios.
As Dr. Snyder explains, patients with intractable pain are also potential candidates for intrathecal pumps. They are typically admitted to the hospital for a short stay and administered a temporary trial medication. Mimicking a permanently placed pump, a catheter is placed to deliver medication directly to the nerves in the spine, and if the patient shows improvement in his or her pain level, Dr. Snyder and his team consider permanent implantation of the pump.
“The primary advantages of the intrathecal pump are the dose is lower than that of oral meds and is delivered exactly where it’s needed, providing the patient with comparable or superior results to oral medications, in addition to a much safer side-effect profile,” Dr. Snyder says. “Furthermore, the peaks and troughs that occur with oral dosing lead to intolerance and worsening pain. Because the pump runs continuously, these potential effects are minimized.”
Seizing Control of Convulsive Attacks
Dr. Snyder was the first neurosurgeon in Long Island to implant the revolutionary NeuroPace, a technology for seizure control in epileptic patients. Epilepsy affects an estimated 3 million Americans and 65 million people worldwide, according to Citizens United for Research in Epilepsy, and costs the U.S. roughly $15.5 billion annually.
Dr. Snyder reviews the location of implanted intracranial grids for long-term seizure monitoring.
“The NeuroPace device allows us to treat epilepsy in a safe titratable fashion by treating electrical disturbances in the brain with electricity,” Dr. Snyder says. “The No. 1 advantage of this new device and therapy is it’s a nondestructive procedure. We can operate on eloquent areas of the brain that have a specific function that we otherwise couldn’t safely operate on. However, this procedure is a safe, reversible treatment that doesn’t entail removing any brain tissue.”
Dr. Snyder and his team conduct diagnostic testing prior to the procedure to identify the precise location in the brain where seizures begin. During the procedure, leads are positioned at the seizure source and the neurostimulator is placed in the skull, hidden under the scalp.
This revolutionary surgical technology and technique, however, is only applicable to focal epilepsies.
Epilepsies are defined as focal or general. General epilepsies begin synchronously throughout the brain, whereas focal epilepsies start in a specific, identifiable place. “By placing the electrodes at the location where the seizures start, the implant is able to detect and stop a seizure before it even begins.”
Roughly one in three people with epilepsy do not benefit from medication management of seizures, making NeuroPace a source of newfound hope.
Leading-edge neurosurgeries, such as DBS, NeuroPace and neuromodulation for pain, have provided patients suffering from disabling effects of many neurological disorders with safe alternatives that address symptom relief.
“Patients fare extraordinarily well with these therapies,” Dr. Snyder says. “Many patients who haven’t found relief from other medical therapies would significantly benefit from an evaluation and potentially treatment from these revolutionary technologies.”
For more information about functional and restorative neurosurgical options available at Neurological Surgery, P.C., visit nspc.com.