Thalamic deep brain stimulation: comparison between unilateral and bilateral placement.

Area of Science:

• Neurosurgery
• Neurology
• Biomedical Engineering

Background:

• Unilateral thalamic deep brain stimulation (DBS) is established for essential tremor (ET) and Parkinson disease (PD).
• Limited data exists on bilateral thalamic DBS efficacy and comparative studies with unilateral DBS are scarce.

Purpose of the Study:

• To evaluate the benefits of a second, contralateral thalamic DBS placement in patients with PD and ET.
• To compare outcomes of unilateral versus bilateral thalamic DBS for tremor management.

Main Methods:

• A comparative study assessed patients (8 PD, 13 ET) before and after initial and second contralateral DBS implantations.
• Outcome measures included the Unified Parkinson's Disease Rating Scale and a modified Unified Tremor Rating Assessment.
• Assessments were conducted with open-label and blinded evaluations of stimulation status.

Main Results:

• Bilateral DBS significantly improved appendicular and midline tremors in both PD and ET patients.
• Midline tremor control (face, head) was achieved only after the second implantation.
• While ET patients showed improved functional and subjective scores, PD patients reported fewer subjective benefits, potentially due to increased adverse events like balance issues.

Conclusions:

• Bilateral thalamic DBS is more effective than unilateral DBS for bilateral tremors in ET and PD.
• Functional disability improved in ET patients, but adverse events were more pronounced in PD patients.
• Bilateral DBS is recommended when unilateral DBS provides insufficient tremor relief, especially for ET patients.