Pilot Study Evaluating Safety of Unilateral Gamma Knife Subthalamotomy for Parkinson's Disease

• Otherwise appropriate DBS candidates but deemed suboptimal for DBS on account of one or more of the following:

• advanced age greater than 74 years of age

• medical comorbidities

• need for continual anticoagulation

• poor candidates for general anesthesia based on cardiac, hepatic ,renal or pulmonary status

• high infection risk if internal DBS device hardware is placed (ie. Poor diabetes mellitus control)

• patient aversion to DBS

• Patients with asymmetric disease symptoms including:

• rigidity

• tremor

• bradykinesia

• dyskinesia

• More than 30% improvement in UPDRS score in ON versus OFF medication state, except:

• in the presence of disabling contralateral dyskinesias/dystonia limiting dose tolerance

• tremors that are medically refractory

• Patients who are on a stable medication regimen and demonstrating stable disease symptoms (absence of significant improvement or deterioration) for at least 3 months at the time of GKS, as determined by review of medical record

• MMSE score greater than or equal to 26