Parkinson's Disease - Surgery

STN stimulation is proving to improve gait, walking ability, and upper limb rigidity in some patients. Its affect on gait, however, may differ from the effects of L-dopa. One study suggested that although improvement occurred, patients did not walk as quickly nor was the stride as long as those on L-dopa. The procedure does not improve gait in patients who do not respond to L-dopa, nor does it help freezing or speech disorders. To date, candidates are generally under 70 who have motor fluctuations, drug-induced dyskinesia, and no other serious medical or psychiatric conditions. Researchers are trying to determine if more patients can be suitable candidates.

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Complications. Complications occur in 2% to 4% of operations. The most serious ones are bleeding in the brain and infection. Depression is common. A 2001 study reported a moderate decrease in verbal memory and mental tasks involving visual-spatial functions. (Some other mental functions improved.) Some experts are not convinced of the safety of implanting a polyurethane device in the brain.

Neurostimulation of the Thalamus. Neurostimulation of thalamus helps patients with tremor. Studies are reporting improvement in tremor in up to 85% of patients, although only on one side of the body. Long-term effects are still unknown, although studies are indicating that it is safe and effective.

Pallidotomy and Other Procedures that Destroy Tissue

Pallidotomy is a surgical procedure that may restore normal brain activity related to voluntary movement in some patients. It is not a cure, however, and its primary benefit is to allow people to continue on medications without incurring some of the side effects. The procedure is irreversible and generally works as follows:

The patient's head is immobilized using a stereotactic frame and imaging techniques are used to visualize the injured areas.
The neurosurgeon drills a small hole into the skull and inserts an electrode.
The electrode generates a current and heat to destroy small amounts of tissue in the globus pallidus, a part of the brain responsible for many Parkinson's symptoms, particularly those that develop after long-term use of levodopa.
The patient is awake during the operation, which takes about six hours.
The hospital stay averages two days.

To date, the standard procedure involves one side of the brain (unilateral pallidotomy). Bilateral pallidotomy (surgery on both sides of the brain) is being researched but to date has higher complication rates than unilateral procedures. Patients should have the surgery performed only in centers that have experience with the procedure.