Comparison of the clinical response of stereotactic ventrointermedial thalamotomy with anatomical and pathophysiological features of parkinson's disease

Abstract

Objective – to investigate the clinical response in the surgical treatment of Parkinson's disease (PD) with levodopa-induced dyskinesias (LID) by stereotactic ablations in the nucleus ventrointer- medialis of thalamus (Vim). Materials and methods. We observed 10 PD patients that underwent ventrointermedial thalamotomy (Vim-thalamotomy) for a resistant tremor combined with the initial LID (Group 1). The study also included 8 patients, with LID development in follow-up after Vim-thalamotomy, previously performed for tremor (Group 2). Results. In group 1 after Vim-thalamotomy, 9 out of 10 patients had an LID control in the contralateral limbs. A similar clinical observation was found in all 8 patients in group 2: while LID manifested on the ipsilateral side of the previously performed Vim-thalamotomy, they did not develop on the contralateral side. Such apparent antidyskinetic effects of our Vim-thalamotomy contradict contemporary knowledge about the anatomical and pathophysiological features of LID. Conclusions. The presence of antidyskinetic effect of Vim-thalamotomy in patients with PD may indicate involvement in the lesion site of the adjacent nucleus ventrooralis posterior (Vop). The localization of the ablation in the two adjacent Vim/Vop nuclei is possible by localization of the stereotactic target, corresponding to the coordinates of 3 mm behind the midcommissural point and/or with the diagonal trajectory of the electrode with an uninsulated tip of 4 mm in length. Taking into account the positive effect on the tremor-LID symptom complex, Vim/Vop-thalamotomy can be proposed as an operation of choice for patients with an appropriate phenotype of PD.

Keywords

• Parkinson's disease, levodopa-induced dyskinesia, thalamotomy.