Functional Neurosurgery and DBS
Deep Brain Stimulation
Deep brain stimulation (DBS) is a minimally invasive targeted surgical procedure primarily used to treat movement disorders in Parkinson’s disease, dystonia and essential tremor. Several new clinical indications are currently evolving including DBS for failed back surgery, Tourette and thalamic pain syndromes, postherpetic neuralgia, trigeminal neuropathy, refractory headaches, epilepsy and some psychiatric disorders.
DBS is performed using a thin, insulated wire electrode, which is inserted in the subcortical structures of the brain and connected to a stimulator (Figure 1). It delivers carefully controlled electrical impulses to precisely targeted areas in the brain that are responsible for patient symptoms. The stimulation may be programmed and adjusted non-invasively by a clinician to help maximize symptom control and minimize side effects. It may take several months to feel the improvement in the patient quality of life and achieve the optimal balance between the stimulation and medications.
In properly selected patients, DBS is quite safe and effective. The most often side effects include bleeding in the brain (1 – 2%), breakage of the device (1%), infection (5%) and sometimes cognitive decline. Some patients may experience temporary problems due to the stimulation itself, which may include dizziness, difficulty with speech or balance and depression. The stimulation parameters can be adjusted to eliminate these symptoms.
Patients should be aware that they can no longer undergo a full body MRI examination and special imaging protocols have to be used for head MRIs. When stem cell and gene therapy becomes available, it still remains an option for the patients that underwent DBS.
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Patients who are diagnosed with Parkinson’s disease, have medically intractable tremor or intolerance to medication side effects and do not have any significant cognitive or psychiatric problems are eligible for DBS. The team of physicians at BNA performs a thorough examination before the procedure to determine if symptoms will respond to DBS. Up to 85% of patients usually achieve reduction in symptoms with about 50% reduction in medications.
Each neurological disorder has specific target neurons and for Parkinson’s disease, these neurons are in the subthalamic nucleus and globus pallidus. The localization of these specific target areas and precise placement of electrodes is achieved using stereotactic 3-dimentional image guidance and electrophysiological exploration techniques. The stereotactic frameless technology used in our clinic does not require patient immobilization during the procedure and therefore is more comfortable for patients.
Dystonia is characterized by uncontrolled movements of a limb and/or the entire body. DBS is performed as an aid in the management of chronic and drug refractory primary dystonia, including generalized and segmental dystonia, hemidystonia, and cervical dystonia (torticollis). It is more effective in the patients with the absence of structural brain abnormalities with an expected 30 to 50% improvement in symptoms after DBS for primary generalized dystonia.
DBS can be effective in the management of all types of tremor including essential, as well as tremor and involuntary movements associated with Parkinson’s disease and multiple sclerosis. The patients that have symptoms not adequately controlled by medications and leading to significant functional disability can be helped by DBS. About 70% of patients with essential tremor report improved activities of daily living and up to 90% reduction of contralateral limb tremor.
Spinal Cord Stimulation (SCS)
Chronic, intractable neuropathic pain afflicts millions of Americans, significantly degrading each patient’s quality of life. Diagnosing and treating complex pain conditions can pose a significant challenge. Treating them successfully is even more difficult. Neuropathic pain often resists conventional pain management therapies, including strong drug regimens.
While various types of neuropathic back pain are receiving increased attention in the medical literature, there is still a lack of knowledge in the community about this type of chronic pain and options for its treatment. There are hundreds of thousands of patients suffering from chronic spine pain and many of them can benefit from Spinal Cord Stimulation (SCS).
Spinal Cord Stimulation (SCS) is an advanced neuromodulation technology that offers effective methods for treating chronic pain of neurologic origin in the back, trunk, and limbs. SCS gives us a clinically proven, drug-free therapy that has been successful in treating pain associated with conditions such as postlaminectomy syndrome, axial low back pain, radiculopathy, peripheral neuropathy, and Complex Regional Pain Syndrome (CRPS).
Pain signals travel along the spinal cord to the brain. SCS therapy applies electrical doses directly to the nerve fibers, changing the pain signal into something the brain interprets as a sensation called “paresthesia.” Patients generally describe it as a gentle tingling or massage-like feeling.
First Step: Trial Period
The first step in SCS therapy is a minimally invasive, reversible outpatient procedure in which the patient receives a temporary, nonimplanted (external) system. Wire leads connect the external trial device to electrode contacts placed over the spinal cord. The system delivers electrical impulses that can mask pain signals.
Second Step: IPG Procedure
Next, a small, rechargeable implant called an Implantable Pulse Generator (IPG) is surgically placed in a comfortable, convenient position under the patient’s skin. Patients often remain awake during this procedure; under local or light anesthesia. Flexible leads that were inserted in the epidural space near the spinal cord are connected to the IPG unit. Each lead has a number of tightly spaced electrode contacts (Figure). The IPG unit produces electrical impulses that travel along the leads to the contacts to deliver pain-masking signals. Afterward, the patient controls the stimulation fields with the same remote control unit used during the trial period.
Click this link to read more about conditions that can be treated with SCS.
Epilepsy is a spectrum of diseases that cause abnormal electrical discharges in the brain resulting in seizures. Often seizures can be managed medically with anti-epileptic medications. However, these medications can have significant side effects and may not control seizures well. Uncontrolled seizure can cause cognitive deficits as well as even death. Patients with medically intractable seizures may be candidates for surgical resection of the area of the brain that is responsible for the abnormal electrical discharges.
The BNA surgical team works with specialized epiliptologists to determine the exact location in the brain responsible for the seizures. This is accomplished by using a combination of imaging modalities, surface electrodes and surgically placed recording electrodes placed both on the surface of the brain and deep into the areas of concern to record the onset of the abnormal electrical discharges. Once the exact location of the discharges is mapped, our specially trained neurosurgeons can resect the precise epileptic focus while leaving normal surrounding structures intact.
After surgery, patients will continue taking their anti-epileptic medications, but most can gradually decrease the dose or discontinue them all together with the help of their neurologist. Surgery for epilepsy has been shown to improve quality of life, decrease the need for seizure medications and allow some epileptic patients to be seizure free with return to activities such as driving and working full time.
For more information on BNA’s DBS program please visit: http://www.exempla.org/body.cfm?id=2046