Similar to available pharmacological treatments, no currently available surgical treatment has been proven to either slow down the disease or "rejuvenate" the sick and dying nerve cells affected by PD. Today's PD surgeries offer only symptomatic benefits.
Because of the level of risk inherent in any brain surgery, it is usually an option only for patients with severe or quickly debilitating Parkinson's disease or those with severe medication-induced side effects, such as debilitating dyskinesias. The decision about whether or not to undergo surgery should be made in consultation with the physicians and caregivers involved in a patient's treatment regimen and, of course, identifying an experienced surgical team is essential.
Deep Brain Stimulation
Today, the most commonly discussed surgical treatment is deep brain stimulation (DBS), a procedure that seeks to reduce "on/off" fluctuations as well as dyskinesias. While we do not understand how DBS works, it seems to counteract the abnormal neuronal functioning that occurs in PD. DBS is increasingly attractive for many advanced Parkinson's patients, particularly as more surgeons become proficient with the technique.
DBS is not well-suited for all patients. Generally, patients with typical PD who have had a good response to levodopa, but who are experiencing medication-related motor side effects, such as dyskinesias may be good candidates. DBS is usually not recommended for patients with dementia.
In DBS, a very thin electrode (about the diameter of a piece of spaghetti) is implanted into the brain, targeting motor circuits that are not functioning properly. Small electrical pulses from a device similar to a cardiac pacemaker are then used to stimulate a small brain region and block the signals that cause some Parkinson's symptoms. DBS may be targeted to the globus pallidus or subthalamic nucleus to improve motor function. The stimulator can be adjusted as necessary to optimize its effects.
Generally, DBS does not improve those symptoms that do not respond to levodopa. DBS may help patients achieve motor function off of medication that is similar to their best pre-operative motor function while on medication, although this is not always the case. DBS also reduces motor fluctuations and off-time. While DBS can produce major improvements in many aspects of PD, this is not always the case. It is important to approach DBS with realistic expectations and an acceptance of the risks and benefits associated with surgery.
Other Surgical Approaches
Because deep brain stimulation has increasingly become the surgical method of choice where it is available, other older surgeries-such as pallidotomies and thalatomies-are used less often than they used to be. Both of these approaches lesion the brain-in effect putting small holes in the brain-to achieve outcomes, and these lesions are not reversible.