There has been a resurgence in the use of functional neurosurgery for Parki
nson's disease. An important factor that has played a role in this developm
ent is the recent understanding of the functional anatomy of the basal gang
lia including a knowledge of the changes in the activities of neurons in th
e internal segment of the globus pallidus (GPi) and the subthalamic nucleus
(STN) in Parkinson's disease as well as the knowledge of the presence of s
egregated functional loops within the basal ganglia which include a sensory
-motor loop that involves the posteromedial globus pallidus rather than the
anterior GPi where earlier pallidotomy lesions had been made. Laitinen rei
ntroduced the modern posteroventral medial pallidotomy (PVMP) in 1992. Sinc
e then it has become clear that this treatment has major effects on levodop
a-induced dyskinesias and, unlike Vim thalamotomy, improves bradykinesia an
d rigidity as well as tremor. In this report, we review a number of topics
related to PVMP including the clinical results of pallidotomy available in
the literature as well as an update of our own 2 year follow-up data, studi
es evaluating factors that might predict the subsequent response to pallido
tomy, the neuropsychological effects of the procedure, results of imaging s
tudies including the correlation of clinical effects with lesion location,
the question of bilateral pallidotomy and pallidotomy combined with deep br
ain stimulation and finally whether PVMP is effective in other parkinsonian
disorders.