The Functional and Restorative Neurosurgery Program specializes in procedures in which electrical stimulating devices, infusion pumps, gene or cellular therapies are implanted within or on the surface of the brain, spinal cord, or peripheral nerves. These are done in order to normalize or modulate abnormal brain function. These are minimally invasive procedures performed through small incisions or openings in the skull, often with the assistance of an imaging device such as a stereotactic headframe or an alternative surgical navigation system.
The functional neurosurgery team, one of the most experienced in the United States, is committed to developing and rapidly adopting new surgical technologies as they become available for the treatment of functional brain disorders, and to refining current surgical techniques in order to make surgery safer and more effective. The team utilizes newer frame-less techniques for performing deep brain stimulation, or DBS, implants and the application of cellular transplantation and/or gene therapies when they are proven effective for the treatment of neurodegenerative disorders.
At the present time, the most commonly performed functional neurosurgical procedure is deep brain stimulation (DBS) for the treatment of medically resistant Parkinson’s disease, Essential Tremor (ET), or Torsion Dystonia. This technology, commercially available in the US since 1997, has improved the lives of thousands of patients afflicted with these disorders worldwide. But this is just the beginning.
It is likely that over the next few years the United States Food and Drug Administration (FDA) will expand the uses of DBS to include medically refractory obsessive-compulsive disorder (OCD), complex-partial epilepsy, and chronic depression. Another technology, vagus nerve stimulation (VNS), which does not even require penetration of the brain, has been approved for the treatment of medically resistant epilepsy for nearly a decade and is approved for the treatment of severe depression. Motor cortical stimulation (MCS) is being evaluated as a treatment for atypical facial pain, Parkinson’s disease, and for enhanced functional recovery following stroke. All of these forms of stimulation therapy are presently available at Mount Sinai.
Conditions We Treat
Parkinson’s Disease (PD)
Parkinson’s Disease (PD) affects approximately one million Americans, making it the second most common neurodegenerative disorder in humans.
Three cardinal features characterize Parkinson's disease: tremor, stiffness (rigidity), and slowness of movement (bradykinesia). Symptoms typically appear in one extremity but soon spread throughout the body. Gait, memory, speech and swallowing disturbances may occur in more advanced cases.
The symptoms of PD are attributed to degeneration (i.e. cell death) within the substantia nigra and other brainstem structures that employ dopamine or related chemicals to signal other regions within the brain. Due to this degeneration, the brains of PD patients have substantially less dopamine than do the brains of normal individuals.
Since the late 1960s, dopamine replacement has been the mainstay of PD therapy. The most effective medication is a combination of levodopa (a precursor to dopamine) and carbidopa. The carbidopa prevents the body from breaking down the levodopa in the bloodstream, allowing more levodopa to reach the brain. The levodopa is taken up by cells within the brain where it is converted to dopamine, restoring brain concentrations.
Additional medications used in the management of PD include dopamine agonists (medications that mimic dopamine within the brain), and medications that slow the breakdown of dopamine, prolonging its effects. Numerous other medications are employed to manage ancillary symptoms.
Essential Tremor (ET)
Essential Tremor (ET), another common disorder of aging, is often mistaken for Parkinson's disease. The key differences between ET and PD are: 1. in ET tremor is the only symptom; 2. the tremor of ET worsens with use of the affected extremity and; 3. ET does not improve with levodopa therapy.
The pathophysiology of ET is poorly understood and medical treatments are often ineffective. The most commonly prescribed medications are beta-blockers such as propranolol and mysoline, which is converted to phenobarbital in the body. Alcohol is probably the most effective “medication”: many patients control their symptoms with an occasional glass of wine.
Dystonia
Dystonia is characterized by twisting/writhing movements and/or abnormal postures. Dystonia is caused by a wide variety of disease states including brain injury, stroke, metabolic abnormalities,and toxins,. Alternatively, dystonia may result as a primary disorder of the brain, in which case a genetic cause is likely. At least 12 gene abnormalities have been associated with primary dystonia.
The Functional and Restorative Neurosurgery Program also provides treatment for these related disorders: clinical depression, obsessive/convulsive disorder, and epilepsy.
