A pilot study: Microlesion effects and tremor outcome in the ventrointermediate deep brain stimulation (VIM-DBS)

Area of Science:

• Neurosurgery
• Neurology
• Biomedical Engineering

Background:

• Deep brain stimulation (DBS) is a therapeutic option for movement disorders like essential tremor and Parkinson's disease.
• The microlesion effect (MLE) is an acute, transient phenomenon observed after electrode implantation in DBS surgery.
• Understanding the relationship between MLE and long-term outcomes is crucial for optimizing DBS therapy.

Purpose of the Study:

• To investigate the association between the microlesion effect (MLE) in VIM-DBS and subsequent tremor response.
• To explore the correlation between MLE and optimal DBS parameter settings (amplitude, pulse width).
• To evaluate the long-term clinical impact of MLE in patients undergoing VIM-DBS.

Main Methods:

• Pilot study involving 12 patients (11 essential tremor, 1 Parkinson's disease) with 19 thalami undergoing VIM-DBS.
• Tremor severity was assessed pre- and post-operatively, at initial activation, and at 6-month follow-up.
• Patients were categorized into minimal, moderate, and marked MLE groups based on immediate post-operative tremor improvement.

Main Results:

• The immediate tremor improvement (MLE) resolved by 6 months in all groups.
• No significant differences in mean tremor scores were observed with 'ON' stimulation across MLE groups at 6 months.
• A trend towards lower amplitude and pulse width settings was noted in patients with a marked MLE.

Conclusions:

• The microlesion effect (MLE) has a limited long-term impact on tremor reduction in VIM-DBS.
• A pronounced MLE might permit the use of reduced DBS stimulation parameters, potentially leading to decreased energy consumption and side effects.
• Further research is warranted to confirm the long-term benefits of MLE-associated reduced DBS settings.