Parkinson's Disease - Surgery

Candidates. In general, appropriate candidates for unilateral pallidotomy are patients with advanced disease who no longer benefit from drug treatments. Unfortunately, only about 5% to 10% of Parkinson's patients are candidates. The procedure is generally not recommended for the following:

Patients who do not respond to levodopa.
The very elderly.
Patients whose primary symptom is tremor.
Patients whose predominant symptoms are freezing and falling (especially during on-periods).
Patients who have serious medical or mental disorders.
Patients with parkinsonism (as opposed to idiopathic Parkinson's disease).

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Benefits. The best results occur in patients with the following symptoms:

Dyskinesia (uncontrolled movements).
Rigidity.
Tremor.

Significant improvements in these symptoms typically occur on the side of the body opposite to where the surgery occurred and such benefits persist in many patients for at least five years. (To a lesser degree, symptoms initially may improve on the same side of the body as the surgery but effect last for a much shorter period of time than the other side.) In one study, half of the patients went from being completely dependent to being able to perform independently, including feeding and dressing themselves. The improvement in daily functioning diminishes over time, although relief even for a few years may be worth it.

Surgery has less effect on the following symptoms:

Balance, gait disorders, and freezing. (In one study, however, about half of patients who could stand independently before the procedure reported better stability and fewer falls. The procedure does not restore the ability to stand independently in patients who could not do so before surgery.)
Voice volume. (Some studies have reported, however, that voice volume improved considerably after surgery in some patients with mild problems, especially when it was performed on the patient's right side.)

Complications. Surgical experience is improving outcomes, but even in centers with high track records, serious and permanent complications occur in 0.41% to 23% of cases. The highest complications are in patients who have bilateral pallidotomy (both sides of the brain). The procedure can even be fatal in rare cases.

Temporary Complications. Most complications are temporary may include facial paralysis, trouble speaking, acute confusion, and sleep attacks.
Permanent Complications. The most common permanent complications included behavioral or personality changes, trouble speaking and swallowing, facial paralysis, and vision problems. Uncommon but very serious complications include stroke (3.9% in one study) and blindness. In one long-term study, complications were permanent in 13.8% of patients with bilateral procedures and fatality rates were 1.2%. Permanent complications occur in 6.4% in those with unilateral pallidotomy and fatality rates were 0.3%.