Non-invasive surgery for tremors offers quick relief with low risk
Magnetic resonance-guided focused ultrasound is a treatment option for patients with essential tremor or tremor-dominant Parkinson's disease who have not benefited from medication or are not willing to have deep brain stimulation. The procedure has also recently been approved by the FDA for unilateral treatment of motor fluctuations and dyskinesias in patients with Parkinson鈥檚 Disease. The procedure uses focused beams of ultrasonic energy guided by MRI to target areas deep in the brain with no incisions or permanent implants.
Baylor Medicine in partnership with Texas Children's Hospital is one of a few selected centers in the United States with the expertise and technology to provide MR-guided focused ultrasound therapy to patients.
Patients
Patients interested in being evaluated to determine candidacy should call 713-798-4696 or email neurosurgery@bcm.edu. Please review the candidate information below.
Physicians
For physicians interested in learning more about MR-guided focused ultrasound or looking to refer a patient.
Treatment Benefits
- Tremor Improvement: 40-80% improvement in tremor severity (many with immediate improvement) stably maintained beyond five years.
- Incisionless: Focused ultrasound technology allows sound waves to pass safely through the skull without incisions. No implants and no radiation required.
- Quick Recovery: With no surgical cuts, there is minimal to no risk of infection. The treatment is often performed on an outpatient basis with local anesthesia, and you can expect to resume normal activities within days.
- Safe and Effective: FDA-approved treatment provides real-time thermal feedback to continuously monitor patient safety and temperature at the target site with minimal side effects.
How it Works
The concept of MR-guided focused ultrasound is much like using a magnifying lens to focus the sun's energy on a leaf. If you put your hand under the magnifying lens, you feel no heat, but the concentrated energy is strong enough to burn the leaf at the focal point. For the treatment of tremor, focused ultrasound therapy is applied on deep brain structures, creating a tiny ablation or lesion (like the pinpoint burn on the leaf). This small lesion created by focusing ultrasound in a specific brain region interrupts the transmission of abnormal brain activity responsible for tremor, leading to tremor reduction and improvements in quality of life. The FDA has approved the use of magnetic resonance-guided focused ultrasound to treat patients with essential tremor or and tremor-dominant Parkinson's disease. More recently, the procedure has been approved for unilateral treatment of motor fluctuations and dyskinesias in patients with Parkinson鈥檚 Disease.
Essential tremor is one of the most common movement disorders, characterized by tremors during outstretched posture or action of the hands. MR-guided focused ultrasound is not a cure for essential tremor but it helps reduce the abnormal brain activity responsible for the tremor, providing meaningful clinical benefits. Focused ultrasound is a viable treatment option when medications or local botulinum toxin injections don't provide adequate tremor control and/or there is poor tolerance to their side effects. This treatment is particularly beneficial in patients whose tremor is most troublesome in one hand. It has a minimal benefit with head or voice tremor. MR-guided focused ultrasound does not affect other associated symptoms such as balance difficulties.
Parkinson's disease is the second most common neurodegenerative condition, affecting about 1% of people over 60 years old. MR-guided focused ultrasound has become an attractive treatment option to improve tremor control for patients who do not respond to dopamine replacement medications. More recently, the procedure was also approved for unilateral treatment of motor fluctuations and dyskinesias in patients with Parkinson鈥檚 Disease.
It is essential to recognize that focused ultrasound is not a cure for Parkinson's disease, and it does not stop the progression of the disease. Some motor symptoms such as balance difficulties, speech problems, swallowing difficulties, and cognitive decline develop or worsen as Parkinson's disease progresses and usually do not improve with focused ultrasound. Similarly, the non-motor complications of Parkinson's disease, such as depression, problems with thinking or memory, constipation, or urinary changes do not improve after focused ultrasound.
Patient Candidacy
It's extremely important to discuss all medical conditions with your physician to evaluate your suitability for the procedure properly. All patients considering focused ultrasound treatment must undergo a screening process. Generally, the steps in the focused ultrasound screening process include:
- Discussion and process initiation with your neurologist.
- Motor evaluation, videotaping of your movement examination, and overall health assessment.
- Your may need to undergo a neuropsychological evaluation to determine various motor and cognitive abilities.
- Computed tomography (CT) scan to measure skull thickness for focused ultrasound calculations.
- Discussion of your focused ultrasound candidacy in a multi-disciplinary conference consisting of a team of neurologists, a nurse practitioner, neuropsychologists, and neurosurgeons.
- Clinic visit with the neurosurgeon who will perform your focused ultrasound treatment to discuss the procedure.
Treatment Day
Preparation
On the treatment day, we begin by giving you a close haircut. This head shave is necessary for the ultrasound waves to be appropriately transmitted through the skin and skull into the target region in the brain. Local anesthesia will be applied to numb areas of your scalp, and a frame will be secured to your head so that your head doesn鈥檛 move during the treatment. We then attach a helmet to the frame. Cool water will circulate in the helmet around the top of your head to minimize potential heating near the scalp.
Your heart rate, blood pressure, and blood oxygen levels will be monitored throughout the procedure. You may be given additional medication to keep you comfortable.
You will also be given a 鈕p sonication鈥 button to indicate to the physician that you want to stop the treatment for any reason.
Planning and Procedure
You will then lie down in the MRI scanner equipped with the focused ultrasound machine. A series of MRI images will be taken for planning the treatment according to your specific anatomy. The treating neurosurgeon will first apply light doses of ultrasound energy and real-time images of the ultrasound delivery will be taken. After each application of energy, called a sonication, you will be asked to perform specific tasks to evaluate your tremor improvement. Tasks may include drawing spirals on a board or performing tasks with your hands. The team will continue to fine-tune the therapy and identify any side effects. The treating neurosurgeon will then apply higher energy to create the permanent lesion. It is common to experience a noticeable reduction in tremor during the procedure itself. At the end of the procedure, a final MRI scan will be done to assess the treatment. The procedure will last approximately between 3-4 hours.
After Treatment
After the procedure, you'll be transferred to a recovery room for a short monitoring period. The frame will be removed. The physician will let you know when you can go home. Within days you should be able to return to normal activities.
FAQ
You must have a confirmed diagnosis of essential tremor or tremor dominant Parkinson鈥檚 disease to be referred for an MR-guided focused ultrasound. Your doctors will also want to be sure you have tried at least two medications and found that they do not help you and/or have undesirable side effects. The severity of your tremor and your overall health will be evaluated as part of the evaluation process.
Patients will need to undergo a CT scan to determine if they are candidates for treatment. You must be at least 22 years old. Since the procedure is done in an MRI scanner, there is a weight limit, generally in the range of 350 lbs.
You may not be able to have this treatment if you:
- Are pregnant
- If you have allergies to contrast dye used during MRI imaging.
- If you have any kind of metallic implants, such as pacemakers, neurostimulators, spine or bone fixation devices, total joints, metal clips, screws, etc. you may not be a candidate. Any metallic implants must be non-magnetic, so you won't be injured by the MRI's strong magnetic field.
- Not able or unwilling to tolerate the required prolonged stationary position during treatment (approximately 3-4 hours).
- Health-related issues such as a recent myocardial infarction (heart attack), congestive heart failure (fluid around the heart), unstable angina pectoris (chest pain), or spinal conditions may be issues that you should discuss with your doctor.
- Have extensive scarring on the scalp
- Have skull tumors
- If you have an active infection or severe hematological, neurological, or other uncontrolled diseases.
NOTE: Parkinson鈥檚 disease patients will undergo an "on/off" evaluation. Parkinson鈥檚 disease symptoms will be assessed under conditions of no medication ("off") and again with the full/maximal effect of medications ("on") to better understand which aspects of your condition improve with medications and which ones are expected to benefit from focused ultrasound. This information helps to determine your candidacy for the procedure and helps you understand what may or may not improve with focused ultrasound.
There is a possibility your tremor may return several months or even years after focused ultrasound, and you might need to be treated again. The tremor also might not improve at all. And while treatment might improve the tremor it does not treat the underlying disease nor prevent the exacerbation or progression of the disease. Doctors can only perform the procedure on either the right or the left side of the brain. This means that the symptoms will improve only on one side of the body. Studies to assess the possibility of treating patients with symptoms on both sides are currently underway.
It is imperative that patients have realistic expectations and a clear understanding of the anticipated outcomes and potential risks before consenting to the procedure.
- After treatment, there is a small risk that you could develop temporary or permanent muscle weakness, unsteadiness when walking, sensory loss, or numbness or tingling in your fingers or elsewhere in your body.
- During the treatment, you may feel a headache or head pain. Nausea and vomiting have been reported during the application of the focused ultrasound energy.
- The most common potential short-term complications, defined as occurring on the day of treatment and up to 3 months following treatment, are transient numbness or tingling - typically mild to moderate in intensity and can last as briefly as the length of the sonication or up to several days.
- Very rarely, focused ultrasound could cause bleeding or skin infection.
- Potential long-term complications, defined as lasting longer than 3-months following treatment, include numbness or tingling, imbalance, unsteadiness, gait disturbance, and muscle weakness.
- The procedure is not recommended for those who have very thick skulls or cannot undergo a brain MRI.
- Additionally, if (unintended) brain tissue is damaged, there may be muscle weakness, numbness, or sensory loss that may resolve after several months, or it may be non-reversible.
Techniques to perform more refined MR-guided focused ultrasound treatments continue to improve over time. Additionally, specialized centers such as BCM count with high resolution neuroimaging techniques to minimize the above risks.
MR-guided focused ultrasound and deep brain stimulation are both surgical procedures for essential tremor and Parkinson's disease. Both are FDA-approved to treat symptoms of essential tremor and Parkinson's disease.
- Focused ultrasound does not require incisions, holes in the skull, or the implantation of electrodes inside the brain and therefore has a reduced risk of infection or bleeding in the brain. Deep brain stimulation does require the implantation of electrodes in the brain, connected to a pacemaker-like battery.
- On the other hand, focused ultrasound creates a lesion (a small region of intentional damage) in the brain and is therefore permanent and irreversible. Deep brain stimulation is an adjustable and reversible therapy.
- Focused ultrasound is typically only used to treat symptoms on only one side of the body. Deep brain stimulation can treat symptoms present on both sides of the body.
- Focused ultrasound may be an option for people who cannot or do not want to pursue deep brain stimulation. Some cannot undergo deep brain stimulation implant surgery because of heart or bleeding problems. Others are not deep brain stimulation candidates because of memory and thinking problems. Still, others do not want to manage the logistics of deep brain stimulation programming and future battery replacements or may not want to have a brain implant. MR-guided focused ultrasound expands the available treatment choices for patients and doctors.
- If you have a deep brain stimulation device, you will not receive focused ultrasound treatment. If you opt to receive focused ultrasound therapy, you still have the option of receiving deep brain stimulation implantation in the future. However, the benefits of deep brain stimulation after having had focused ultrasound treatment are still unclear.