Functional and Stereotactic Neurosurgery
Functional neurosurgery is defined as “destruction or chronic excitation of part of the central nervous system to treat a disorder of function or behavior”. An important tool developed over the past two decades for treatment of functional neurological disorders such as Parkinson’s disease, essential tremor and dystonia is deep brain stimulation (DBS). Deep brain stimulation placement surgery utilizes stereotactic neurosurgical techniques and imaging studies (MRI and/or CT) to identify discrete targets within the brain and guide the approach to these targets. Typically, the surgery is performed in a minimally-invasive fashion through a very small opening in the skull called a burr hole. We believe that success in functional and stereotactic neurosurgery is dependent on contributions from experts in several disciplines, including neurology, neuropsychology, neurophysiology and anesthesiology. In addition, expert post-operative DBS programming is essential for the ultimate success of the therapy. Our team has performed over 250 DBS implant surgeries to date and is uniquely qualified to provide both the required multidisciplinary expertise and the uncommon personalized care of each patient. Studies evaluating the efficacy of DBS in the treatment of other functional disorders, including depression, epilepsy and obsessive-compulsive disorder are currently under way. Stereotactic radiosurgery (described below) is also a very important tool in the treatment of certain functional disorders such as trigeminal neuralgia.Expand all
Deep brain stimulation (DBS) is the preferred surgical option when symptom management -— for Parkinson’s disease, essential tremor or dystonia — is not achieved to the patient’s satisfaction by medication. In this procedure, a small electrode is implanted in the symptom-specific site of the brain. The electrode is connected, by a thin wire that runs under the skin, to a battery pack (called a neurostimulator) implanted under the collarbone. The neurostimulator sends electrical impulses along the wire to the electrode, and can be adjusted to ensure greatest possible symptom control for the patient.
Unlike earlier surgeries used to address the symptoms of movement disorders — which destroyed a very small part of the brain — deep brain stimulation has the benefit of being reversible, and does not preclude the use of other therapies as they become available in the future.
Surgery becomes a treatment option for people who have Parkinson’s disease, when their symptoms are no longer adequately controlled by medication. Each person experiences different symptoms and each person tolerates both symptoms and medication differently. For one person, advanced disease may worsen symptoms beyond medication control, suggesting surgical intervention. For another, quality of life or job-related issues may necessitate surgery in an earlier stage. There is no right or wrong time to consider surgery, though there are indications against surgery, including other serious illnesses (i.e., some cardiac disease or pulmonary disease) or Parkinson’s dementia.
Though thalamotomy and pallidotomy are still performed for Parkinson’s disease in certain situations, deep brain stimulation is now the surgery of choice. Specifics of each patient’s symptoms typically guide the choice of target in the brain for implantation of a deep brain stimulator. Most often, the subthalamic nucleus (STN) or globus pallidus internus (GPi) are the targets used to treat Parkinson’s disease symptoms. Whether electrodes are implanted on one or both sides of the brain (in two separate surgeries, if on both sides) will be determined by whether or not symptoms are equally severe on both sides of the body. DBS most often provides significant improvement in symptom control and allows welcome reduction in medication.
Essential tremor is a very common but complex movement disorder. In most people, essential tremor is mild and can be controlled by medication. For some, however, the tremor is so severe that it causes disability or significantly impacts quality of life and cannot be adequately controlled by drug therapy. Thalamotomy, in which a portion of the thalamus deep within the brain is destroyed, was the neurosurgery of choice for essential tremor until the advent of deep brain stimulation and is still used today under certain circumstances. Most often when a thalamotomy is performed today, however, it will be done using stereotactic radiosurgery (see below). The essential tremor patient electing to have deep brain stimulation surgery usually experiences significant tremor relief. The usual target in the brain for deep brain stimulation for treatment of symptoms of essential tremor is the ventral intermediate nucleus (ViM) of the thalamus.
Dystonia patients unable to obtain symptom relief from medications or Botox injections should consider deep brain stimulation as an alternate therapy. Bilateral DBS of globus pallidus internus (GPi) usually produces substantial improvement in symptoms in patients with primary generalized dystonia (i.e., dystonia not resulting from injury to the brain by tumor, stroke, trauma, etc.) DBS has also been shown to be beneficial in persons with segmental cranio-cervical dystonia. Response to DBS in patients with secondary dystonia has not been as encouraging.
Normal pressure hydrocephalus (NPH) is a treatable cause of memory loss, difficulty walking and incontinence in elderly individuals. Treatment usually involves placement of a ventriculoperitoneal or a lumbar-peritoneal shunt to divert excess spinal fluid from the brain. Careful diagnostic work-up is essential for patients suspected of having NPH since other degenerative conditions may mimic NPH, but do not respond to treatment with a CSF shunt. Recent technological advances, including the development of programmable shunt valves, have made surgery for NPH safer and have decreased the need for re-operation.
Trigeminal Neuralgia (tic douloureux, TN) is a neuropathic disorder of one or both of the trigeminal nerves (5th cranial nerves). This condition may cause one of the most severe pains that a human being can experience, and may be difficult to control with medications. TN usually develops after the age of 50 and is more common in females. The condition is caused by a vessel (artery or vein) compressing the trigeminal nerve adjacent to the site of its entry into the brainstem. The pain may involve the ear, eye, lip, nose, scalp, forehead, teeth or jaw. The pain is usually described as “stabbing” or “electric-shock” like, and may be brought on or worsened by cold wind, chewing, talking or even touching the face.
Treatment with medications is the first line of defense for patients with trigeminal neuralgia. When medications do not provide adequate control of pain or produce unacceptable side-effects, the possibility of surgical treatment should be considered. For healthy patients, microvascular decompression (i.e. direct decompression of the trigeminal nerve via a craniotomy) is usually the treatment of choice, since it provides the highest probability of long-term relief of pain. For patients who are not healthy enough to undergo a craniotomy or who prefer a less invasive procedure, stereotactic radiosurgery represents a very good treatment alternative, providing long-term pain relief in about two out of three patients.
Stereotactic radiosurgery (SRS) is a minimally-invasive approach for treatment of benign and malignant brain tumors and other neurological diseases such as vascular malformations, pain syndromes and movement disorders. The most common neurological diseases to be successfully treated with radiosurgery include meningiomas, acoustic neuromas, pituitary adenomas, brain metastases, craniopharyngiomas, arterio-venous malformations, and trigeminal neuralgia. Recent technological advances such as the CyberKnife radiosurgical system also allow treatment of benign and malignant tumors of the spine, including spinal metastases.
Radiosurgery involves computer-guided, extremely precise delivery of high doses of radiation. By avoiding open craniotomy or spine surgery in appropriate patients, radiosurgery frequently decreases the risks associated with traditional treatment of neurosurgical conditions. In situations where a brain lesion cannot be safely approached by a craniotomy, because of its association with critical brain structures, radiosurgery may represent the only treatment option. Radiosurgery is typically an outpatient procedure and patients usually resume normal activities immediately after treatment. Over the past decade there have been significant advancements in the field of stereotactic radiosurgery in conjunction with enhanced imaging capabilities and computing power. These technological advancements have resulted in improvement in patient outcomes and have extended the capabilities of radiosurgeons to safely treat a wider variety of neurosurgical conditions. Currently the most widely used systems for delivery of radiosurgery are linear accelerators, CyberKnife and Gamma Knife.
We offer radiosurgical treatments utilizing CyberKnife or linear accelerator. The choice of the specific radiosurgical tool typically depends on the specific disease, the size, and the location of the target to be treated.