Results of STN stimulation compared with other stereotactic procedures

Chronic stimulation within the subthalamic nucleus (STN) has gained increas ed interest for the treatment of advanced Parkinson's disease during the la st years. The studies published so far demonstrate a good response of Parki nsonian off-symptoms like akinesia, rigidity, tremor as well as impaired po stural reflexes. In a long-term levodopa-induced dyskinesias (LID) as well as fluctuations improve significantly. Side effects are transient and can b e abolished by change of stimulation parameters. Severe adverse events like bleedings or infections are rare and are outweighed by the positive effect s of stimulation. Until now there are no larger studies comparing the curre nt stereotactic treatment options in a prospective, randomised fashion. Com paring STN- to Vim-stimulation demonstrates a comparable effect on Parkinso nian tremor with clearly more effect on other Parkinsonian off-symptoms as well as LIDs favouring STN-stimulation. A comparison between STN-stimulatio n and stimulation of the Gpi shows a similar effect on off-symptoms slightl y favouring STN-stimulation. The improvement of LIDs and fluctuations is co mparable. Reduced Levodopa intake post surgery as well as less stimulation energy needed for the same therapeutical effect are an advantage of STN-sti mulation. In comparison to unilateral pallidotomy, STN-stimulation shows a better effect, especially on midline symptoms and a comparable reduction of LIDs. Levodopa reduction with pallidotomy is not possible in most studies. Compared to other stereotactic procedures, the improvement of Parkinsonian off-symptoms such as akinesia, rigidity, tremor and impaired postural refl exes with STN-stimulation is similar if not better. The decrease of LIDs is comparable to Cpi-stimulation and pallidotomy. Randomised studies, however , are necessary to compare long-term outcome as well as economic factors an d quality of life between the currently available stereotactic procedures.