Comparison of subthalamic deep brain stimulation with pedunculopontine nucleus stimulation in the treatment of Parkinsonian motor and axial symptoms with and without subthalamic stimulation

Aims: The study compares efficacy of Pedunculopontine Nucleus (PPN) Deep Brain Stimulation (DBS), subthalamic DBS and combined PPN-subthalamic stimulation in the treatment of advanced Parkinson's Disease (PD). Methods: MEDLINE/PubMed, EMBASE, and Cochrane Library were searched for studies published before September 1, 2015. Search terms included various combinations of "subthalamic", "pedunculopontine", "deep brain stimulation" and "Parkinson disease". Two investigators independently examined titles, abstracts, and references. Results of studies on clinical outcomes of PPN DBS and subthalamic DBS for PD were analysed. Therapeutic outcomes of included studies were evaluated using Unified Parkinson's Disease Rating Scale III (UPDRSIII). Meta-analysis was performed using Review Manager Software version 5.3. Results: Three studies were included in the meta-analysis. Subthalamic DBS reduced UPDRSIII scores (off-medication phases) to levels lower than PPN DBS. However, improvement in UPDRSIII axial subscores (on-medication phases) after PPN DBS was greater than that after subthalamic DBS. UPDRSIII scores for combined PPN-subthalamic DBS were not significantly different from subthalamic DBS (on-and off-medication phases). Improvements in UPDRSIII axial subscores for combined PPN-subthalamic DBS were significantly greater than subthalamic DBS (on-and off-medication phases). Conclusions: The study demonstrates differences in therapeutic efficacy for Parkinsonian motor and axial symptoms between PPN DBS and subthalamic DBS based on UPDRSIII scores and axial UPDRSIII subscores. PPN is a better target for PD gait disorders than subthalamic nucleus in on-medication phases. Subthalamic DBS has similar effect on postoperative motor features with combined PPN-subthalamic stimulation. Combined PPN-subthalamic DBS is more effective than subthalamic DBS in treating axial symptoms of PD.