Therapeutic extradural cortical stimulation for Parkinson's Disease: Report of six cases and review of the literature

OBJECTIVES We report our experience and results with extradural cortical stimulation (ECS) in the surgical treatment of Parkinson's Disease (PD). Besides, we review the literature supporting the use of this technique. MATERIALS AND METHODS Six patients with advanced PD and exclusion criteria for Deep Brain Stimulation (DBS) were included in our ECS protocol. With the aid of functional MRI and somato-sensory evoked potentials monitoring, the motor cortex projection over the scalp was drawn. Finally, under local anesthesia a stimulation lead was placed in the epidural space overlying the central sulcus. RESULTS Patients showed mild daily life activities improvement with a slightly lower levodopa equivalent dose, but UPDRS part III scores showed no significant modification. CONCLUSIONS Despite ECS is a minimally invasive surgical technique, our results only support its use in selected patients with advanced PD, in whom this therapy may be modestly effective. More experimental studies regarding the neuromodulation of the basal ganglia-cortex loops are required to optimize its clinical application.