Efficacy and safety of unilateral chronic Epidural Motor Cortical Stimulation in neurosurgical treatment of Advanced Parkinson's Disease

Extradural Motor Cortex Stimulation (EMCS) is a minimally invasive therapy that has been employed in cases of neuropathic central pain. We believe that it might be proposed in Parkinson’s disease (PD) for patients excluded or unresponsive to DBS. Ten patients with advanced PD underwent unilateral EMCS by epidural implanting of quadripolar plate electrode over M1 through a single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment was performed by Total UPDRS, UPDRS III total, UPDRS III-items 27-31, UPDRS IV and UPDRS II before implantation in off-medication and on-medication states and after surgery at 1, 3, 6, 12, 18, 24, 36 months in on-medication/on-stimulation and off-medication/on-stimulation states. We assessed changes of QoL with Parkinson’s disease QoL scale (PDQoL-39), the dose of anti-Parkinson’s disease medications with L-Dopa Equivalent Daily Dose (LEDD). During OFF-medication state we observed moderate and transitory reduction of Total UPDRS and UPDRS Total scores, significant long-lasting improvement in UPDRS III items 27-31 score for axial symptoms. There was marked reduction of UPDRS IV score and LEDD and prolonged amelioration of activities of daily living. PDQL-39 improvement was significant from 6 months to 24 months evaluation. No severe complications and adverse events occurred. Despite the limited small sample, results suggested that in PD patients excluded from DBS treatment the unilateral MCS is a safe and minimally invasive surgical alternative with significant and prolonged effects on axial symptoms, complications of antiparkinsonian drugs therapy and activities of daily living.