PALLIDOTOMY - EDITORIAL REVIEW

Parkinson's disease treatment remains one of the greatest challenges i n neurology. Although L-Dopa is the mainstay of treatment, in the 1990 's the role of functional surgery has been rediscovered. In the post-d opa era the profile of Parkinson's has changed. Many patients have int olerance to high doses of L-Dopa, disabling diskynesias and on-off phe nomena. This particular group of patients that failed pharmacological treatment and show severe rigidity, bradykinesia, and dyskinesia seem to benefit from ventro-posterolateral pallidotomy. The organization as well as the afferent and efferent pathways of the basal ganglia (glob us pallidus, striatum, substancia nigra, subthalamic nucleus) will be discussed. The loss of dopaminergic projections on the globus pallidus result in increased activity of the inhibitory output of the globus p allidus over the thalamus that ultimately turns back in the cortex. Th us, the fundamental goal of this stereotactic procedure is to abolish selectively the pallidal hyperactivity. Surgical patient selection and evaluation is a critical issue. Better surgical candidates include yo unger patients responsive to L-Dopa that have mainly dyskinesia and ri gidity with clear on-off fluctuations and asymmetric symptoms. Patient s with Parkinson's Plus, dementia, supranuclear gaze palsy, and focal lesions seen on magnetic resonance imaging scans are excluded in most of the clinical protocols. The radiofrequency lesion is placed in the ventral and posterior aspect of the internal segment of the globus pal lidus as defined in the CT-SCAN and MRI images. Intraoperative appropr iate location is confirmed with microelectrode recordings. The results of early and the recent clinical series will be reviewed. Although mo re extensive clinical trials are required to establish the long term e fficacy of this technique in the treatment of Parkinson's disease, com plete control of dyskinesias and significant relief of rigidity, bradi kynesia and tremor have been reported.