Functional surgery for Parkinson’s disease treatment: A structured analysis of a decade of published literature
Boucai, L., Cerquetti, D., & Merello, M. (2004) Functional surgery for Parkinson’s disease treatment: A structured analysis of a decade of published literature , 18, 213-222
The objective of this study was to look at the different approaches to surgical intervention over the last ten years for Parkinson’s disease. The authors commented that advances in our understanding of brain function combined with improving technology resulted in increased surgical intervention for PD. They noted the three main areas for surgical targets include the "internal pars of globus pallidum subthalamic nucleus, and intermediate ventral thalamic nucleus" (the last more so for treatment of tremor). To look at surgical efficacy, the authors decided to conduct a meta-analysis (large review of many research papers) from 1990-2001 and came up with 88 papers out of 560 that met their stringent criteria. They noted that many studies were not included due to not enough patients included and the authors of the original studies did not follow-up with the cases for a long enough amount of time (at least 1 month). The authors were generally interested in motor scores pre and post surgical intervention. There were 64 papers looking at GPi, 17 for STN, and 7 on both nuclei. There was variable usage of macrostimulation and microrecording during surgery. The majority of procedures used MRI for target localization, while other imaging techniques were also used (CT, ventriculography, teleradiography). 1702 patients underwent surgery and the male to female ratio was 1.5:1. The mean age was 58.75 with no differences between age and site of surgery. Additionally, there was no difference between duration of disease and site of surgery (GPi vs. STN). There was inconsistent reporting of medication usage, activities of daily living scores on the UPDRS, and dyskinesias pre and post surgery. Notably, 28 papers did not mention postsurgical complications. Of the studies that reported complications, the majority were reversible complications versus permanent. Specifically, 34.64 % of patients in the STN group had reversible complications and 0% had permanent complications. Whereas 23.31% of the GPi patients had reversible complications and 4.1% had permanent complications. The most common complications in general were confusion, followed by dysarthria, weight gain, facial weakness, hemorrhage, hemiparesis, visual disturbances, speech problems, and dysphagia. They concluded that bilateral DBS STN procedures were associated with a more favorable outcome. The authors conclude by discussing the limitations of the meta-analysis (heterogeneity of the data) as well as cautions that there may be underreporting of less successful surgery outcomes that would bias the current literature in the favorable light for surgical options.