Efficacy comparison of subthalamic and globus pallidus internus deep brain stimulation in Parkinson′s disease with dyskinesia

Abstract

Objective To compare the therapeutic effects of subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) on Parkinson′s disease (PD) with levodopa-induced dyskinesia (LID), and to explore the possible underlying mechanism. Methods A total of 27 PD patients with LID treated with STN and GPi-DBS from August 2015 to October 2017 at Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University were retrospectively enrolled. Among them, 14 underwent STN-DBS and 13 underwent GPi-DBS. Patients were evaluated preoperatively and every 6, 12, 18 months after surgery. The primary outcome was assessed based on the Unified Dyskinesia Rating Scale (UDysRS). The secondary outcome was investigated according to the Unified Parkinson Disease Rating Scale part Ⅲ (UPDRS-Ⅲ), levodopa equivalent dose (LED), stimulation parameters and side effects. Results Both STN-DBS and GPi-DBS group showed significant improvement in LID, while GPi-DBS exerted higher LID improvement (F=15.326, P 0.05). The improvement of UPDRS-Ⅲ at the 18 month follow-up was 44.7%±20.0% and 45.7%±17.1%, respectively for STN and GPi-DBS. The LED reduction rate was higher in STN-DBS group (F=4.693, P<0.05). The LED reduction rate at the 18 month follow-up was[M(P25, P75)] 44.8(26.7, 80.2)%and 14.0(0, 41.3)%, respectively for STN and GPi-DBS.The stimulation voltage and pulse width of the GPi-DBS group were higher than those of the STN-DBS group (F values were 4.435 and 21.415 respectively, P<0.05). In the STN-DBS group, there were 5 cases of stimulation induced dyskinesia (SID), 1 case of electrode fracture, and 1 case of incision infection.There were 1 case of SID and 1 case of bradykinesia in the GPi-DBS group. Conclusions Both STN and GPi-DBS could improve dyskinesia. Compared with STN-DBS, GPi-DBS seems to have a stronger effect on improvement of LID. The anti-dyskinesia effect of STN-DBS may be related to drug reduction and adjustment of stimulation sites, while GPi-DBS might exert a direct anti-dyskinesia effect. Key words: Deep brain stimulation; Subthalamic nucleus; Globus pallidus internus; Levodopa-induced dyskinesia; Levodopa equivalent dose