PATIENT SELECTION: PARKINSON’S DISEASE DEEP BRAIN STIMULATION

CANDIDATES FOR DBS THERAPY

Best results are achieved when the patient and caregiver are fully informed about the therapy risks and benefits, surgical procedures, follow-up requirements, and self-care responsibilities.

Consider deep brain stimulation when a patient has:

• Symptoms of levodopa-responsive Parkinson's disease of at least 4 years' duration that are not adequately controlled with medication.
• And motor complications of recent onset (from 4 months to 3 years) or motor complications of longer-standing duration.

A patient must also be a suitable candidate for stereotactic neurosurgery.

In 2002, the FDA initially approved Medtronic DBS Therapy for use in patients with advanced Parkinson’s disease. Medtronic DBS of the STN improved quality of life and motor function as shown in a Level I evidence clinical study of patients of at least 4 years disease duration and recent onset of motor complications.¹ Based on the clinical evidence, in 2015 the FDA approved Medtronic DBS Therapy for use in people with Parkinson’s disease starting with those who have recent onset of motor complications. This means clinicians no longer have to delay consideration of Medtronic DBS Therapy until the disease has become debilitating.

Medtronic DBS Therapy is also appropriate for patients with longer-standing motor complications, and there is no upper age limit restriction, as shown in a post-approval Level 1 evidence clinical trial.²

The safety and effectiveness of deep brain stimulation therapy for Parkinson's disease have not been established for patients who:

• Have a neurological disease other than idiopathic Parkinson's disease
• Had a surgical ablation procedure
• Are pregnant
• Are under the age of 18
• Have dementia
• Have coagulopathies
• Have moderate to severe depression

Use extreme care with lead implantation in patients with a heightened risk of intracranial hemorrhage. Physicians should consider underlying factors, such as previous neurological injury or prescribed medications (anticoagulants), that may predispose a patient to the risk of bleeding.

Physicians should be aware that the risks associated with initial surgery may increase with clinical conditions such as:

• Stroke or neurological disorders other than idiopathic Parkinson’s disease
• Cardiovascular disease
• Renal or hepatic failure
• Diabetes mellitus

To help ensure maximum benefits from the neurostimulation system, long-term, post-surgical management of patients is recommended.

Stimulation parameters should be adjusted such that maximal symptom suppression is achieved with minimal side effects. High parameter values may indicate a system problem or less than optimal lead placement. Patients should be informed of the risks of higher parameters as noted in the appropriate information for prescribers booklet.

REFERRAL FOR EVALUATION

Clinicians may refer candidates to a DBS multidisciplinary center for a comprehensive evaluation for possible Medtronic DBS Therapy.

The evaluation usually includes:

• Medical history
• Neurological exam of movements, both on and off medications
• MRI of the brain to check whether there are any issues that would pose a risk during the surgery
• Lab tests, such as a blood test to make sure blood clots properly
• Neuropsychological tests

Opportunity for DBS

Deep brain stimulation for Parkinson's disease has a window of opportunity when it may be most effective.

The window opens when a patient has Parkinson's disease of at least 4 years' duration that is not adequately controlled by medication, including motor complications for at least 4 months or motor complications of longer-standing duration. You may observe one or more of the following:

• "On" time characterized by disabling dyskinesias (or other nonmotor side effects)
• "Off" time characterized by disabling tremor, rigidity, or akinesia/bradykinesia
• Unpredictable "on/off" motor fluctuations
• Medication-resistant tremor

The window closes when:

• Symptoms no longer respond to dopaminergic medication.
• The patient is severely disabled even in the best "on" state.
• Medical conditions prevent surgery.
• The patient has dementia.

Introducing patients to DBS as a future option can help prepare them to start therapy in time to take advantage of their window of opportunity.