Posteroventral pallidotomy: its effect on motor symptoms and scores of MMPI test in patients with Parkinson's disease.

Stereotaxic pallidotomy for Parkinson's disease (PD) is an old concept, which was gradually and mostly replaced by thalamotomy. Recently, posteroventral pallidotomy (PVP), originally proposed by Leksell et al., was reintroduced; this paper examines PVP in terms of its historical background, technical aspect and location of the surgical lesion, as well as clinical effects on motor and psychological symptoms. Posteroventral pallidotomy has been shown to be satisfactory in relieving rigidity and secondary akinesia, but not powerful enough in alleviating severe tremor. These are similar observations to those made in classical pallidotomy. For this reason, all PVP-treated cases reported in this paper have an additional small thalamic lesion for control of tremor. Also, it must be recognized that most of the surgically treated patients are continuing to take medication at the same or slightly lowered dose compared with preoperatively. Dopa-induced dyskinesia is alleviated well by PVP, similar to thalamotomy. The most important question is whether PVP has more effect on truncal symptoms, such as postural imbalance, and on gait than thalamotomy, a question that is still not satisfactorily answered in both clinical and basic analysis. Parkinson's disease-induced changes in emotional status, such as depression or hypochondriacal complaints, are favorably influenced by PVP, but not by thalamotomy. The role of stereotaxic surgery in the era of pharmacological treatment is discussed, as is the possible importance of the role of the limbic-motor circuit in research on PD.