Spinal Cord Stimulation for Parkinson's Disease: A Systematic Review and Meta-Analysis of Pain and Motor Outcomes.

BACKGROUND: Spinal cord stimulation (SCS) has been investigated as a potential therapeutic option for managing refractory symptoms in patients with Parkinson's disease (PD). OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the safety and efficacy of SCS in PD. METHOD: A comprehensive literature search was conducted on PubMed and Web of Science to identify SCS studies reporting Unified Parkinson Disease Rating Scale-III (UPDRS-III) or Visual Analogue Scale (VAS) score changes in PD cohorts with at least 3 patients and a follow-up period of at least 1 month. Treatment effect was measured as the mean change in outcome scores and analyzed using an inverse variance random-effects model. The risk of bias was assessed using the Newcastle-Ottawa Scale and funnel plots. RESULTS: A total of 11 studies comprising 76 patients were included. Nine studies involving 72 patients reported an estimated decrease of 4.43 points (95% confidence interval [CI]: 2.11; 6.75, p < 0.01) in UPDRS-III score, equivalent to a 14% reduction. The axial subscores in 48 patients decreased by 2.35 points (95% CI: 1.26; 3.45, p < 0.01, 20% reduction). The pooled effect size of five studies on back and leg pain VAS scores was calculated as 4.38 (95% CI: 2.67; 6.09, p < 0.001), equivalent to a 59% reduction. CONCLUSIONS: Our analysis suggests that SCS may provide significant motor and pain benefits for patients with PD, although the results should be interpreted with caution due to several potential limitations including study heterogeneity, open-label designs, small sample sizes, and the possibility of publication bias. Further research using larger sample sizes and placebo-/sham-controlled designs is needed to confirm effectiveness.

Multicenter Validation of Individual Preoperative Motor Outcome Prediction for Deep Brain Stimulation in Parkinson's Disease.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson's disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort. METHODS: DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes. RESULTS: 322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%. CONCLUSION: Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.