Functional neurosurgery involves the restoration of neurological condition and function. The treatment of chronic neurological disorders involves the use of a variety of techniques, including neuromodulation and deep brain stimulation.
Although the main treatment for Parkinson’s is medication, there are some types of surgery available to treat the symptoms of this condition.
Surgery is generally only used to treat people who have had Parkinson’s for some time and whose symptoms are not managed effectively by medication. It may also be used for people who experience problems with involuntary movements. Not everyone will be suitable for surgery, so you may want to discuss this option with your specialist.
Patients should consider for surgery if they meet the following criteria:
- Intact intellectual function and memory. Dementia (significantly impaired memory or thinking) is a major contraindication to surgery.
- History of significant benefit from taking levodopa (Sinemet).
- Certainty of diagnosis. A number of neurological illnesses can mimic the symptoms of Parkinson’s disease but do not respond significantly to levodopa, these conditions usually do not improve with surgery.
- Lack of other untreated or inadequately treated illnesses.
- Realistic expectations. People who expect a sudden miracle are disappointed with the results, and they may have difficulty with the complexity of the therapy.
- MRI of the brain should be free of severe vascular disease, extensive atrophy, or signs of atypical Parkinsonism.
- Mild degree of disability.
- Ability to remain calm and cooperative during an awake neurosurgical procedure lasting 2-3 hours per brain side
Essential tremor (ET) is the most common movement disorder. It is a progressive, often inherited disorder that usually begins in later adulthood. Patients with ET typically experience tremors when the arms are held up and when the hands are being used for activities like eating, drinking or writing. The tremors also may affect the head, voice, tongue and legs and worsen with stress, fatigue and stimulant medications.
Essential tremor is thought to be caused by electrical fluctuations in the brain that send abnormal signals out to the muscles. In some patients, tremors can be reduced by weighting the limb, usually by applying wrist weights. In a small proportion of patients, this can dampen down the tremor enough to provide some relief or improve functioning.
The decision to treat with medications is made when the degree of impairment or discomfort outweighs the side effects of treatment. The mainstay medications include beta-adrenergic blockers and anti-seizure medications.
When patients do not achieve satisfactory control of their tremor with non-medical or medical therapies and there is significant functional impairment, surgical options should be considered.
Brain operations to treat various forms of dystonia were first performed 40-50 years ago. The operations involved a precisely controlled lesioning (destruction) of deep structures in the brain involved in movement control.
In the last years there has been a resurgence of interest in the surgical treatment of dystonia. There are several reasons for this; Techniques for operating on deep brain structures have become much more precise and safe. In addition to the older technique of brain lesioning, there is a new technique, deep brain stimulation (DBS), which involves placing a stimulation electrode rather than performing a brain lesion. DBS can alter the function of abnormal brain tissue in a way that improves movement, but it is reversible if there is an unwanted effect, and it can be adjusted during a routine office visit to optimize the degree of benefit.
Patients should consider surgery for dystonia if they meet the following criteria:
- The patient has been evaluated and treated by a qualified movement disorders neurologist who has clearly diagnosed the type of dystonia, and excluded other neurological problems.
- The dystonia adversely affects quality of life by interfering significantly with normal activities or causing social isolation.
- The patient’s neurologist has attempted treatment with a variety of medications, which should at least include Sinemet and anticholingergic medications.
- The dystonia affects too large a body area to be treated effectively with injections of botulinum toxin (Botox); or attempts at injection with Botox have been tried and failed.
- The patient and family clearly understand the nature and complexity of DBS therapy as well as the fact that the therapy is too new to guarantee successful treatment in any individual case.
In addition to the above considerations, surgery for dystonia appears to be more effective for certain forms of dystonia than others. Primary dystonia’s (patients without brain abnormality on MRI) are more likely to benefit than those with secondary dystonia (patients with brain abnormalities seen on MRI that are causing the dystonia).
Currently the accepted therapeutic approach to most psychiatric disease involves a combination of psychotherapy, pharmacotherapy and, in some instances, electroconvulsive therapy. However, despite these modern treatment methods, some patients fail to respond adequately and remain severely disabled. Nowadays, only patients with chronic, severe and disabling psychiatric illness that are completely refractory to all conventional therapy are considered for surgery.
Psychiatric neurosurgery involves the surgical ablation or disconnection of brain tissue with the intent of altering abnormal affective and behavioral states caused by mental illness. It is classified as a functional neurosurgical procedure because it attempts to improve or restore function by altering underlying physiology.
There is general agreement that patients with these conditions are the best candidates for surgery:
- Major depressive disorder
- Obsessive compulsive disorder
- Chronic anxiety states
- Addiction to substances
- Aggressive behavior
- Tourette’s syndrome
- Ablative surgery
- Deep brain stimulation
- Vagus nerve stimulation (for depressive disorder)
Although many psychosurgical techniques have been used in the past, different procedures have evolved as the safest and most effective. These are all performed bilaterally under modern stereotactic conditions to allow for precise identification and accurate lesioning of the target structures. All forms of these modern procedures seem to be safe and well tolerated with few side effects or complications.
SURGICAL TECHNIQUES FOR PSYCHIATRIC DISORDERS
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