Surgery

Surgical treatments for dystonia may be an option for individuals whose symptoms do not respond to oral medications or botulinum toxin injections. Researchers are actively refining current techniques and collecting information about which patients may benefit the most from surgical treatments.

There is no single surgical procedure that can be applied to all forms of dystonia. Surgical procedures for dystonia can be divided into two broad categories: brain surgery and peripheral surgery. Peripheral surgery includes procedures that target parts of the body other than the brain.

In both brain and peripheral procedures, the goal of surgery is to interrupt the faulty communication between the brain and muscles that causes involuntary muscle movements. Surgery intends to treat symptoms and improve function but does not cure the underlying condition.

Because dystonia is a chronic disorder, the management of symptoms is an ongoing, lifelong process. Just as medications and botulinum toxin injections are often not singular solutions to an individual’s dystonia, surgery is one component of the total management of dystonia. Surgery does not necessarily eliminate the need for additional forms of treatment. However, in many cases surgery improves quality of life and reduces the need for medications or botulinum toxin. Like all surgical interventions, operations to treat dystonia are associated with the risk of certain complications. The success of any surgical procedure lies heavily in proper diagnosis, the experience of the clinical team, and the skill and artistry of the surgeon.

The patient selection process for determining if an individual is a candidate for surgery is deliberate and precise. Only a neurologist or neurosurgeon who specializes in movement disorders can recommend surgery for dystonia. The cost of surgery varies by procedure and medical center, and coverage is often on a case-by-case basis for Medicare, Medicaid, and private insurance.
 

Peripheral Surgeries
 

The symptoms of dystonia occur when muscles of the body receive faulty information from the brain causing them to contract involuntarily. These faulty messages originate most commonly in a part of the brain called the basal ganglia. These messages are conveyed over brain pathways to the spinal cord and, from the spinal cord, reach the muscles via nerves.

Peripheral surgeries occur outside the brain and generally target the specific nerves and muscles affected by the incorrect messages from the brain. Peripheral surgeries are generally used to treat focal dystonia. An exception is intrathecal baclofen, which targets the spinal cord and is used to treat generalized or hemidystonia. However, for the purpose of this discussion, intrathecal baclofen is included under the category of peripheral surgeries.

Cervical Dystonia
 

The Bertrand Procedure: Selective Peripheral Denervation
Selective peripheral denervation surgery for cervical dystonia is commonly referred to as the Bertrand procedure. In the 1970s, Dr. Claude Bertrand, with the collaboration of Dr. Pedro Molina-Negro, developed this procedure as a peripheral approach to treat cervical dystonia. The term selective refers to the care taken to identify the muscles of the neck affected by dystonia, and the termdenervationrefers to cutting the nerves that supply those muscles. The purpose of the Bertrand procedure is to reduce abnormal contractions in the affected muscles by severing the nerves to these muscles. The goal of the procedure is to leave intact the supply of nerves to unaffected or less-affected muscles.

This procedure is tailored to address the unique needs and symptoms of each patient. The initial approach is often to denervate the muscles causing the most prominent dystonic movement, knowing that some residual movements may remain from lesser-affected muscles. If the results do not sufficiently alleviate symptoms, a second procedure may be performed. In many cases, the initial surgery is enough to significantly improve the abnormal posture. More aggressive surgeries, in which all cervical muscles involved in the dystonia are denervated in a single operation, may result in excessive weakness in the neck.

An essential part of the procedure is the pre-operative evaluation to properly identify the muscles involved and to assess if the procedure will benefit the individual. Patients who may be eligible for the surgery are observed clinically by the physician and with EMG equipment to monitor muscle activity and pinpoint the muscles affected by the dystonia.

One basic element of the Bertrand procedure is to cut rootlets of the spinal accessory nerve, which supply sternocleidomastoid muscles in the neck, and to spare the nerves to the trapezius muscle. The spinal accessory nerve is one of 12 cranial nerves that originate in the brainstem, which is the junction of the brain and the spinal cord. A second element of the Bertrand procedure is cutting the posterior rami (branch) of one or more spinal nerves along the cervical vertebrae. (This element of the procedure is called posterior ramisectomy.) Spinal nerves are arranged in pairs along the length of the spinal cord and supply muscles and organs. Some research suggests that the ramisectomy increases the improvement in persons who have become resistant to botulinum toxin therapy.

To date over 2,000 cervical dystonia patients have undergone this procedure. Some centers report significant improvement in as many as 88% of cases. Although the procedure may benefit individuals with a range of symptoms, the categories of patients who may have the best results from the Bertrand procedure are individuals in which:
• Symptoms mainly affect the neck
• Symptoms have stabilized for 3 years
• The head turns to one side (rotational torticollis)
• The head is tilted (laterocolis)
• The head turns and is pulled backwards (rotational torticollis with superior retrocollis)
• The head turns and tilts forward (rotational torticollis with superior antecollis)
• The head is pulled back (superior retrocollis)

Dystonia in which the head turns both to the side and either back or forward may have the best outcome. Individuals who respond to botulinum toxin therapy as well as non-responders may be eligible. The procedure may also be an option for a small number of patients with generalized dystonia who have very defined symptoms in the neck.

Side effects may include numbness in the back of the head, tightness at the surgery site, some remaining movements, difficulty swallowing, and lack of benefit. Patients are often able to go home after two or three nights in the hospital.

Studies have demonstrated that the Bertrand procedure can significantly improve the posture of the neck with a better range of motion. Physical therapy following the procedure is very important to preserve range of motion.
 

 

Laryngeal Dystonia - Selective Denervation and Reinervation
 

Selective laryngeal adduction denervation and reinnervation (SLAD/R) is a surgical procedure to treat adductor spasmodic dysphonia/laryngeal dystonia by cutting (denervating) selected end branches of the recurrent laryngeal nerve, which is a branch of the vagus cranial nerve.

The first attempts to reduce the spasms of spasmodic dysphonia by severing the laryngeal nerve took place in the 1970s. Cutting the laryngeal nerve paralyzed the muscles controlling one side of the larynx so that the larynx could not contract excessively. Early results were good, but symptoms reappeared in many patients. Subsequent pioneers in the field sought to improve the procedure by varying the method by which the nerve was separated from the muscle. Recurrence of symptoms as well as breathy voice continued to be a problem in many patients.

The element that distinguishes SLAD/R from previous incarnations of the surgery is that, after the recurrent laryngeal nerve is cut away from the thyroarytenoid and lateral cricoarytenoid muscles, the muscle's nerves are hooked up to another nerve (reinnervated), one that is not associated with the dystonia. Supplying the muscle with another nerve prevents the problematic branch of laryngeal nerve from growing back and reconnecting to the muscle. Preventing the laryngeal nerve from communicating to the muscle prevents the spasms from returning and helps to change the closing forces of the larynx. It is important to note that the procedure is performed on both sides of the vocal cords, unlike previous nerve operations performed for adductor SD.

The procedure is accomplished through an incision in the neck and by creating a small window into the laryngeal cartilage to expose the underlying nerves and muscles. An operating microscope is often used to aid in identification and suturing of the tiny nerve branches. The procedure takes three or four hours to complete. Great care is taken to preserve the back part of the cartilage that protects the nerve branches to the breathing muscles.

SLAD/R is best suited for individuals with spasmodic dysphonia without a tremor. It may be an option for persons who are not satisfied with botulinum toxin treatments. Hundreds of people with spasmodic dysphonia have undergone SLAD/R. During the initial recovery period, all patients experience temporary voice breathiness and some experience swallowing difficulty. These issues resolve over a few months and the patient is left with an improved voice. Studies have indicated that as many as 85-90% of patients are very satisfied with the results of surgery, and the results, so far, have been life long.
 

 

Blepharospasm- Myectomy Surgery

Surgical removal of the eyelid and brow-squeezing muscles is referred to as a myectomy procedure and is used to treat blepharospasm. Myectomy prevents the muscles surrounding the eyes from being stimulated by removing the muscle.

Before the availability of botulinum toxin, myectomy was essentially the only treatment option for blepharospasm. The introduction of botulinum toxin injections in 1989 benefited many persons with blepharospasm thereby changing the population of individuals eligible for myectomy. Candidates for myectomy became those for whom botulinum toxin is not sufficient.

Just as the patient selection changed, the procedure itself evolved. Initially, the procedure involved removing all eyelid-squeezing muscles in both upper and lower lids as well as the brow area at one time. At the present time, the procedure is tailored to the needs of the patients. It is most common for the surgeon to remove the muscle in the upper eyelids and brow (full upper myectomy) and then re-evaluate the need for a lower myectomy at a later date. Patients heal faster when the procedure is done in stages, and some individuals do not require the lower myectomy.

The full upper myectomy may be done entirely through an eyebrow incision. The incision lies immediately adjacent to the brow hair and allows access to the upper lid orbicularis muscle, and part of the lower lid orbicularis muscle as well as the procerus and corrugator muscles in the brow area. Most of the orbicularis muscle is removed during the eyelid surgery. A strip of dense muscle is left at the margin of the upper eyelid to help maintain some voluntary closure and to protect the eyelash roots.

A limited upper myectomy is a partial upper myectomy. It is available for those individuals who are benefiting from botulinum toxin but need something extra to restore function of the eyes. It may be helpful for those patients who have apraxia (difficulty opening the eyes) or for those who in addition to blepharospasm have ptosis (drooping lids). Partial removal of the orbicularis may subsequently decrease the need for botulinum toxin in these patients. A limited myectomy is done through an upper eyelid crease incision and involves removal of the orbicularis muscle within the upper lid area only. Because there is less tissue removal than the full upper myectomy, patients recover in less time. A limited myectomy also gives more predictable cosmetic improvement because less tissue is removed. It is not designed to replace a full upper myectomy. Most patients will still require botulinum toxin injections following the limited myectomy procedure.

Persons who have stopped responding to botulinum toxin as well as those rare individuals who fail to respond at all may be eligible for myectomy. Individual surgical centers have treated hundreds of blepharospasm patients with myectomy. Techniques used for cosmetic surgery, such as sculpting the fat beneath the brow and manipulating the placement of the brow, may be implemented to provide a beneficial aesthetic as well as functional result.

Myectomy surgery can be done under local or general anesthesia. The healing process following a myectomy may take up to a year. In most cases, the patients are able to keep their eyes open immediately following the operation. However, considerable swelling, hematomas (blood accumulation in lid), lymphedema (tissue fluid), and bruising may be present early in the post-operative period and prevent complete eyelid opening. Cool compresses in the first four to five days followed by warm compresses are very helpful at settling the lid swelling and bruising.

There are numerous potential side effects associated with myectomy surgery that are predictable and, to some degree, occur in most patients. Numbness of the forehead region often occurs and is usually temporary but may last a year or more. Loss of tissue volume in the eyelid area may occur with the muscle removal, but the improved brow, lid position, and decreased eyelid wrinkling generally gives an improved cosmetic appearance. Decreased eyelid closure occurs as a result of eyelid muscle removal and may require the need for additional artificial tears and lubricating ointment. As the eyelid swelling resolves, the eyelid closure improves and the dry eye symptoms generally improve. Chronic lid swelling which may last six months or longer in some patients can be a chronic and troublesome complication. Chronic lid selling is much less severe and persistent in the modern myectomy practices in which upper and lower lid myectomies are performed separately. Infection, hematoma, brow hair loss, and abnormal positioning of the lower lid can occasionally occur but are uncommon.

Patients continue to improve in function as well as in appearance for about six months to a year after myectomy surgery. Reports have shown that visual disability is improved in approximately 90% of patients. Some patients have more improvement than others. Touch-up procedures are required in some cases, and some individuals continue to require botulinum toxin injections.
Generalized Dystonia - Intrathecal Baclofen
Intrathecal Baclofen: The Baclofen Pump
Baclofen (Lioresol®) is a medication introduced in the late 1960s as a treatment for spasticity. The medication is also commonly used to treat select cases of dystonia. Baclofen in the spinal fluid around the brain and spinal cord supplements the body’s supply of a chemical neurotransmitter called GABA, which relaxes muscle movement. The drug may be given orally, but very high doses must often be used to ensure that the drug saturates the blood stream and reaches the spinal fluid. High doses of oral baclofen may cause intolerable side effects such as muscle weakness and fatigue. A surgically implanted baclofen pump delivers baclofen directly to the spinal fluid, and only very small doses are needed. (The term intrathecal means in the spinal fluid.)

Intrathecal baclofen therapy is a non-destructive, adjustable, and reversible treatment. Several hundred dystonia patients have been treated with intrathecal baclofen. It has been used for children and adults with generalized dystonia (both primary and secondary) and hemidystonia who respond to oral baclofen. Many persons treated with intrathecal baclofen have a combination of dystonia and cerebral palsy. Intrathecal baclofen may be used to treat dystonia affecting the upper and lower limbs.

In order to determine if an individual is eligible for intrathecal baclofen, he/she will undergo a screening test to observe the body’s response to baclofen. A response to the oral drug may necessitate a screening test to observe the body’s response to a small dose injected directly into the spinal fluid. The medication is injected using a standard lumbar puncture. The screening test procedure involves injection of the medication followed by several hours of observation. Relaxation of the muscles indicates that an implanted baclofen pump will likely be effective. The effects of the screening test are temporary and may last several hours after the injection. If a patient does not respond at all to the screening test, a second test using the same procedure may be tried the next day or at a later date.

Some physicians use a continuous intrathecal infusion of baclofen as a screening method, since more patients respond to continuous infusion than to single injection screening doses. In the infusion technique, a small catheter is inserted into the spinal fluid and is connected to an external pump that infuses baclofen in increasing doses over two to three days.

Starting intrathecal baclofen therapy involves surgically implanting a pacemaker-like device into the abdomen. The device is usually placed either to the right or left of the belly button, beneath the skin and fat of the abdomen. The pump is connected to a thin tube that is tunneled around the side of the body to the back. A small needle introduces the tube to the spinal canal. Once the surgical incisions are closed, the pump is adjusted by a remote computerized device to deliver the amount of medication appropriate for the individual. The procedure takes one to two hours, and hospital stay may range from four to seven days. Modest improvement of symptoms may be noticeable before the individual is discharged from the hospital, and it make take six months or more to achieve the full extent of benefit.

Regular maintenance is a key component of intrathecal baclofen therapy. Regular exams and physical therapy may be a component of postoperative care. Pumps must be refilled every one to four months in the physician’s office as a straightforward outpatient procedure. The pump is refilled by inserting a thin needle through the skin, into the pump. The frequency of refilling the pump depends on the dose required. If necessary, the doctor may adjust the delivery rate of the pump at the time of the refill by remote control. The pump battery needs to be replaced about every seven years.

Baclofen in the spinal fluid relaxes muscles throughout the body, and appears especially effective for targeting dystonia in both the upper and lower half of the body. Intrathecal baclofen may be more effective for treating secondary dystonia than for primary dystonia.

Studies have shown that intrathecal baclofen can dramatically improve symptoms and quality of life. Some centers have reported significant improvement in as much as 85% of patients. However, like any surgery, the procedure is not without risks. Hardware complications may also arise including infection and catheter breakage and disconnection. In a small percentage of cases, patients may lose effect within the first year of therapy or experience a worsening of symptoms. The most common side effects are constipation, decreased muscle control, and drowsiness.
 

Generalized Dystonia - Intrathecal Baclofen
 

Intrathecal Baclofen: The Baclofen Pump
Baclofen (Lioresol®) is a medication introduced in the late 1960s as a treatment for spasticity. The medication is also commonly used to treat select cases of dystonia. Baclofen in the spinal fluid around the brain and spinal cord supplements the body’s supply of a chemical neurotransmitter called GABA, which relaxes muscle movement. The drug may be given orally, but very high doses must often be used to ensure that the drug saturates the blood stream and reaches the spinal fluid. High doses of oral baclofen may cause intolerable side effects such as muscle weakness and fatigue. A surgically implanted baclofen pump delivers baclofen directly to the spinal fluid, and only very small doses are needed. (The term intrathecal means in the spinal fluid.)

Intrathecal baclofen therapy is a non-destructive, adjustable, and reversible treatment. Several hundred dystonia patients have been treated with intrathecal baclofen. It has been used for children and adults with generalized dystonia (both primary and secondary) and hemidystonia who respond to oral baclofen. Many persons treated with intrathecal baclofen have a combination of dystonia and cerebral palsy. Intrathecal baclofen may be used to treat dystonia affecting the upper and lower limbs.

In order to determine if an individual is eligible for intrathecal baclofen, he/she will undergo a screening test to observe the body’s response to baclofen. A response to the oral drug may necessitate a screening test to observe the body’s response to a small dose injected directly into the spinal fluid. The medication is injected using a standard lumbar puncture. The screening test procedure involves injection of the medication followed by several hours of observation. Relaxation of the muscles indicates that an implanted baclofen pump will likely be effective. The effects of the screening test are temporary and may last several hours after the injection. If a patient does not respond at all to the screening test, a second test using the same procedure may be tried the next day or at a later date.

Some physicians use a continuous intrathecal infusion of baclofen as a screening method, since more patients respond to continuous infusion than to single injection screening doses. In the infusion technique, a small catheter is inserted into the spinal fluid and is connected to an external pump that infuses baclofen in increasing doses over two to three days.

Starting intrathecal baclofen therapy involves surgically implanting a pacemaker-like device into the abdomen. The device is usually placed either to the right or left of the belly button, beneath the skin and fat of the abdomen. The pump is connected to a thin tube that is tunneled around the side of the body to the back. A small needle introduces the tube to the spinal canal. Once the surgical incisions are closed, the pump is adjusted by a remote computerized device to deliver the amount of medication appropriate for the individual. The procedure takes one to two hours, and hospital stay may range from four to seven days. Modest improvement of symptoms may be noticeable before the individual is discharged from the hospital, and it make take six months or more to achieve the full extent of benefit.

Regular maintenance is a key component of intrathecal baclofen therapy. Regular exams and physical therapy may be a component of postoperative care. Pumps must be refilled every one to four months in the physician’s office as a straightforward outpatient procedure. The pump is refilled by inserting a thin needle through the skin, into the pump. The frequency of refilling the pump depends on the dose required. If necessary, the doctor may adjust the delivery rate of the pump at the time of the refill by remote control. The pump battery needs to be replaced about every seven years.

Baclofen in the spinal fluid relaxes muscles throughout the body, and appears especially effective for targeting dystonia in both the upper and lower half of the body. Intrathecal baclofen may be more effective for treating secondary dystonia than for primary dystonia.

Studies have shown that intrathecal baclofen can dramatically improve symptoms and quality of life. Some centers have reported significant improvement in as much as 85% of patients. However, like any surgery, the procedure is not without risks. Hardware complications may also arise including infection and catheter breakage and disconnection. In a small percentage of cases, patients may lose effect within the first year of therapy or experience a worsening of symptoms. The most common side effects are constipation, decreased muscle control, and drowsiness.
Brain Surgeries
 

The goals of brain surgery for persons with dystonia are to decrease muscle spasms, increase mobility and function, and improve pain.

There are currently two categories of brain surgery for dystonia: lesioning procedures, which involve selective destruction of targeted, abnormal brain tissue, and deep brain stimulation(DBS), which mimics the effects of lesioning by manipulating selective brain areas with non-destructive electrical pulses.

Although risks exist, case studies have shown that both lesioning procedures and DBS can result in marked improvement of dystonia with minimal complications. Some patients are able to decrease or altogether stop drug therapy following surgery.

Dystonia most often originates in a part of the brain called the basal ganglia which are involved in the coordination and control of muscle movements. The basal ganglia are a group of structures that include the globus pallidus (also called the pallidum), the thalamus, and the subthalamic nucleus. Lesioning procedures for dystonia usually target the globus pallidus or the thalamus; deep brain stimulation usually targets the globus pallidus or subthalamic nucleus. The globus pallidus is responsible for the output of messages from the basal ganglia. The recipient of this output is the thalamus. The subthalamic nucleus is a tiny structure located directly beneath the thalamus and is connected to the globus pallidus.

Different parts of the brain work together to help the body accomplish a specific task, such as tapping the foot. The parts of the brain communicate via circuits or pathways of individual brain cells that transmit chemical messages from one to the other. In an individual with dystonia, the circuits that facilitate the movement of the foot are disrupted by abnormal activity. The goal of brain surgery is to free up the circuits so that the brain and body may accomplish the intended function—in this case, moving the foot.

Brain surgery may be performed unilaterally (on one side of the brain) or bilaterally (on both sides). The effects of surgery occur on the side of the body opposite to the surgical site.

To date, most persons who have undergone brain surgery for dystonia were treated for generalized dystonia. However, individuals who may be eligible for brain surgery include persons with focal, segmental, or generalized dystonia with significant, disabling symptoms that do not respond satisfractorily to other therapies. Adults as well as children with primary and secondary dystonia may be eligible.

Based on the limited available data, different categories of patients may respond differently to brain surgery. Although cases of both secondary dystonias (including tardive dystonia) and focal dystonias may be eligible, it appears as though persons with DYT-1 generalized dystonia are the best candidates for brain surgery—either lesioning or DBS. Studies have shown as much as 60-90% improvement in DYT-1 patients treated with lesioning or DBS. Patients with secondary hemidystonia may be eligible for brain surgery, though they may not benefit as much as those with DYT-1 dystonia. Researchers are examining the possibility that persons with secondary dystonia may get greater benefit from lesioning or DBS to the thalamus rather than the globus pallidus.

There is limited data about the long-term effects of each approach. Brain surgery for dystonia is an evolving science, and investigators are continually collecting information.
 

 

Lesioning Procedures: Pallidotomy & Thalamotomy
 

The practice of lesioning parts of the brain in dystonia patients was very common in the 1950s and 1960s, since at that time it was essentially the only available treatment for severe cases. These procedures, as practiced over 50 years ago, had mixed results. By the 1980s, brain surgery for dystonia had widely fallen out of favor and was not widely practiced. However, the increased understanding of the basis of movement disorders such as Parkinson’s disease and the success in treating it with surgical approaches, plus the development of brain imaging technology, led to a re-evaluation of surgery as an option for patients with dystonia.

The procedure that involves creating a therapeutic lesion in the globus pallidus is called pallidotomy, and the procedure that involves creating a lesion in the thalamus is called thalamotomy. A permanent lesion is made in the brain tissue by heating the tip of an electrode and coagulating the intended tissue.

When lesioning surgery is chosen, pallidotomy is now preferred over thalamotomy and provides a reasonable alternative to pallidal DBS for patients who are averse to the cosmetic appearance of the implanted pulse generator or do not want to be burdened by repeated battery replacements. Bilateral pallidotomy has shown an average of 67-80% improvement in the Burke-Fahn-Marsden dystonia rating scale in patients with generalized dystonia. Primary generalized patients may respond better than focal or secondary dystonias. In Parkinson's patients, bilateral pallidotomies are avoided because they cause hypophonia, a quieting of speech. This has not been observed in dystonia patients, and many dystonia patients have had bilateral pallidotomies without significant worsening of speech.

Although thalamotomy was once the most common brain surgery performed for dystonia, it is now used almost exclusively in cases of stable hemidystonia, and a very specific site in the thalamus is targeted. The procedure is performed unilaterally. Bilateral brain surgeries increase the risk of complications, and bilateral thalamotomies in particular are known to often cause speech impairment.

The primary factor that distinguishes modern lesioning procedures from those of 50-plus years ago is that surgeons are able to locate the lesioning target more accurately. The following factors make it much easier for the surgical team to locate the target within the brain, which is crucial to reducing the risk of complications:
• Stereotactics—Surgeons are able to target the precise area of the brain with a computerized, 3-dimensional scale using MRI and CAT scans.
• Microelectrode recording and brain mapping—The surgical team has the ability to listen to the sounds of brain cells firing messages to one another. Cells in different parts of the brain fire at very specific rates and in characteristic patterns, and by listening to these cells the surgeon knows exactly where the electrode is within the brain. Several recording tracts may be necessary to identify the precise target.

Once a physician has recommended brain surgery, and pre-operative screening tests and preparations are complete, the basic plan of operation for pallidotomy and thalamotomy are the same. The individual is fitted with a head frame under general or local anesthesia. The brain is mapped with imaging technology to create a blueprint for planning and measuring the placement of the electrode. Under local anesthesia, the electrode is inserted through a small hole in the skull into the brain. The brain itself does not feel pain, and the patient is awake during most of the procedure. The surgical team interacts with the patient throughout the procedure, and the patient provides feedback about symptoms and how he/she feels. Microelectrode recording is used to confirm the target. The mapping procedure alone may take up to several hours. Once the target is defined, the surgeon inserts the thermal electrode and creates a lesion. The thermal electrode is removed and the procedure is complete. A bilateral procedure may be done in a single surgery or in two separate surgeries. If a second target is to be lesioned, the mapping procedure is repeated for that specific target. Most patients are in the hospital for two or three days. Medications may be temporarily resumed, and after a short time the patient returns to the neurologist for a follow-up exam.

There is a small but real risk of complications associated with lesioning. The most serious risk is a 1-2% incidence of stroke or hemorrhage during the mapping phase of the surgery. Also, the target of the pallidotomy, the internal segment of the globus pallidus, is located right above the optic tract which may be damaged if the electrode is not targeted precisely. There also exists the risk that the pallidotomy will not improve the symptoms. However, the procedure has been shown to dramatically improve dystonia in some patients.
 

 

Deep Brain Stimulation
 

Deep brain stimulation (DBS) involves implanting stimulating electrodes into selected targets in the brain in order to mimic the effects of lesioning. Surgeons began using DBS in place of lesioning for Parkinson’s disease patients in the mid-1990s. DBS also has applications to tremor and pain. Whereas DBS has been used to treat thousands of persons with Parkinson’s disease, the procedure began being applied to dystonia less than 10 years ago. It is estimated that just under 1,000 dystonia patients have been treated with DBS.

Bilateral pallidal DBS produces significant benefit in dystonia with average improvements of about 50-60% in the Burke-Fahn-Marsden dystonia rating scale. Some primary generalized patients have been reported to have up to 90% improvement. DBS has also been performed on persons with secondary dystonias, cervical dystonia, segmental dystonia, and myoclonic dystonia with encouraging results.

The complete DBS apparatus includes the DBS electrode, a connecting wire, and a pulse generator (a.k.a. “brain pacemaker” or stimulator) that contains a battery. The initial procedure to implant DBS is identical to that of the pallidotomy and thalamotomy. Once the brain target is mapped and identified, instead of creating a lesion, the surgeon places the DBS electrode into the target. The wire and pulse generator may be implanted at the same time as the electrode or at a later date. The generator is implanted under the collarbone, and the wire is tunneled up the neck, behind the ear, and to the site of the electrode (the patient is under general anesthesia for this part of the procedure). The wire is connected to the electrode, and the incisions are closed. Most DBS procedures involve the implantation of two generators and are done in two surgeries. It is possible to implant both generators in a single surgery, and surgical centers vary in their preferred approach. Immediately after the operation, the patient may temporarily resume medications. The patient may be discharged the next day.

Once the generator is implanted, the patient must wait a week or two before the batteries are activated. This waiting period is necessary to allow the swelling that normally occurs with the surgery to diminish. The DBS electrode conveys electrical pulses into the brain using power produced by the battery in the generator. A series of visits to the hospital are required to adjust the voltage settings to the needs of the individual. It may take several weeks or months to achieve the correct settings. The patient can check the status of the generator using a handheld device that resembles a TV remote control. Using this device, the patient can determine if the generator is on or off, and can turn it back on in the event that it shuts down unexpectedly. (Certain phenomenon such as magnetic fields caused by security devices may cause the battery to temporarily stop working.)

The expected life span of a battery at a typical voltage is about four years. At a very high voltage, the battery may need to be replaced after a year; at a very low voltage, perhaps up to seven years. Replacing a battery can be done under general or local anesthesia as an outpatient procedure.

Dystonia does not respond to DBS in the same as other movement disorders do. For example, persons treated for tremor will generally improve within seconds of turning the generator on. In patients with dystonia, improvement may be delayed for days, and weeks or months may pass before the full extent of the benefit is reached. DBS does not necessarily eliminate the possibility of subsequent drug or botulinum toxin treatments.

Side effects are minimal, but no procedure is without risks. The main risk in DBS is a fatal hemorrhage. However 99-99.5% of patients do not have significant bleeding. Despite vigorous efforts to avoid it, infection is a risk in approximately 2% of patients. Infection can be serious and warrant the removal of the hardware. If this happens, it may be possible to re-implant the hardware once the infection is treated. Hardware failure is also a concern, though this is rare and precautions are in place in the event of situations such as a battery failing. It is estimated that in 5% of DBS procedures for dystonia some complication may arise, most of which can be addressed without removing the hardware.

Although no longer considered “investigational” for dystonia by the United States Food & Drug Administration, DBS is in its relatively early stages as a treatment for this disorder. The preliminary results are quite positive, and the procedure is expected to evolve over time as more patients are treated and more data is collected.
 

 

Comparing Lesioning & Deep Brain Stimulation
 

Studies have shown that both lesioning and DBS can dramatically improve dystonia. Both approaches are associated with a small, but real, risk of complications. There has not been a clinical study to compare the results of lesioning procedures and DBS, and the advantages and disadvantages of each remain an open issue.

Lesioning procedures and DBS have many elements in common including:
• Patient selection criteria
• Area of brain targeted
• Basic surgical procedure
• Potential for profound benefit to eligible patients
• Risk of complications including hemorrhage during surgery, hemiplegia or hemiparesis, sensory impairments, speech/language impairment

In both cases, the surgery is lengthy. While every effort is made to help make the patient comfortable, both procedures require the individual to remain awake and responsive for hours at a time while in positioned in a head frame. The chance of benefit must be weighed against the risk of complications. No two cases of dystonia are alike, and determining the specific approach to treatment—in this case lesioning or DBS—must be decided after careful discussions among the patient, family members, the neurologist, and neurosurgeon.

Of the dystonia patients who are eligible for brain surgery, more individuals are currently being recommended for DBS than pallidotomy. The pallidotomy, however, is not an obsolete procedure. Unless a patient is against having hardware installed in his/her body, the tendency is to try DBS before proceeding to the pallidotomy because DBS is adjustable and reversible.

Financial and geographical issues cannot be overlooked. Persons who have DBS must visit the doctor regularly for maintenance check-ups. People who live in remote areas or areas not in proximity to a major movement disorder center may be at a disadvantage. Travel to and from the center—and the expense of this travel—is a part of the ongoing management required of DBS patients.

Because lesioning creates a permanent change in the brain tissue, there is a slightly higher risk of permanent complications during the surgery such as swallowing difficulty, speech difficulty, and cerebral hemorrhage. Because DBS involves the implantation of hardware, complications associated with the apparatus are possible, including infection, erosion through the skin, hardware breakage, and stimulator failure. The risk of hardware complications exists for as long as the hardware is implanted.

It remains to be seen whether the pallidotomy or DBS is more effective than the other. The experience of the surgeon and medical team are the most important determinants of success and risk. The lowest incidence of complications occurs in major medical centers that perform these procedures often. Patients should choose a center with a long-standing expertise in movement disorders and a clinical team devoted to surgery for dystonia and movement disorders. A movement disorder neurologist and a surgeon should be specially trained in functional surgery, and an electrophysiologist should be on staff for brain mapping. An experienced nursing staff is also important.

Complementary Therapy
 

Complementary care is often a very important component of an individual’s treatment plan. Speak with your doctors, support group leaders, and other people with dystonia to help discover options that might work for you. Explore the following possibilities:
• Relaxation techniques
• Body-mind techniques such as yoga, meditation, the Feldenkrais Method
• Gentle and controlled physical exercise including Pilates and soft martial arts
• Biofeedback
• Acupuncture for pain relief
Traditional western practices such as medications and surgery have long been effective at diagnosing problems and assigning treatments, but may not fully address how patients live on a daily basis. These medical fields are slowly incorporating a wider range of knowledge to include treatments outside of the traditional scope to better assist patients and to treat the "whole person"—body, mind, and spirit. Complementary therapy may play an active role in your treatment of dystonia, and it is intended to be used in conjunction with traditional therapies. To avoid any interactions and potential problems, it is important to have open communication among all physicians and practitioners who are working with you.

It is very important that any practitioners of complementary therapies who you consult are familiar with dystonia or willing to learn about it prior to treating you. The DMRF can provide materials to help you educate your healthcare professionals.

Children & Brain Surgery
 

Children over the age of seven are eligible for lesioning and DBS, although the longer one waits, the less brain and skin growth will occur after the operation. However, there is little data available about long-term effects of DBS and how a child’s development may affect the hardware. Steps can be taken during surgery to ensure that the apparatus can accommodate the child’s growth. Children and adolescents may be at a slightly higher risk of complications from DBS because general rather than local anesthesia is often used during implantation and post-operatively children are more likely to engage in rough play that may affect the hardware.

Surgery does not necessarily have to be considered only as a last resort. Certainly, if an individual is satisfied with how symptoms respond to a less invasive treatment such as botulinum toxin or medications, there is no need to consider brain surgery. However, especially in children, early intervention may significantly improve quality of life. The benefits of brain surgery include more than improved mobility—a child’s ability to function comfortably at school (both academically and socially), to make friends, and to be active are important factors to consider. In both children and adults, brain surgery can drastically improve pain, which is often a major component to a person’s quality of life.