Role of surgery in Parkinsons Disease treatment
What is the role of surgery in the treatment of Parkinsons Disease?
Deep Brain Stimulation of the ventralis intermedius of the thalamus (VIM) has been shown to be of marked benefit, primarily for tremor, and is able to suppress dyskinesias.
Deep Brain Stimulation involves implanting an electrode in the VIM and delivering high-frequency chronic stimulation via an implantable pulse generator located subcutaneously in the subclavicular area.
Patients can turn the device on and off via an external magnet.
Deep Brain Stimulation can be done bilaterally with a lower risk of dysarthria than thalamotomy.
The recognition that Parkinsons Disease is associated with hyperactivity of the STN led to a successful treatment of MPTP monkeys by subthalamotomy.
Some human patients, inadvertently treated with subthalamotomy instead of thalamotomy, noted improvement not only in tremor but also in bradykinesia.
STN Deep Brain Stimulation has demonstrated in numerous studies to provide benefit for contralateral bradykinesia, dyskinesia, and other parkinsonian signs.
This was demonstrated by the improvement in off-period motor symptoms and activities of daily living in a recent meta-analysis.
Patients most likely to benefit had severe off-period symptoms, long disease duration, and a history of good presurgical response to levodopa.
The pallidum, particularly the posteroventral part of the GPi, is also a surgical target in Parkinsons Disease.
The main benefit of pallidotomy is the marked reduction of contralateral LID, with some ipsilateral benefit. Tremor, bradykinesia, and rigidity are also reduced but more variably.
After pallidotomy, patients typically have a lower levodopa requirement.
Deep Brain Stimulation into the GPi is receiving increased attention as a treatment for LID as well as other hyperkinesias, including dystonia and tics.
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