Rescue deep brain stimulation for recurrent essential tremor after ventral intermediate nucleus thalamotomy:...

Area of Science:

• Neurosurgery
• Neurology
• Medical Devices

Background:

• Medication-refractory essential tremor (ET) often necessitates surgical intervention like MR-guided focused ultrasound or Gamma Knife thalamotomy.
• Tremor recurrence post-thalamotomy may require rescue deep brain stimulation (DBS), but the effects of prior lesioning on DBS are unclear.

Purpose of the Study:

• To investigate the impact of prior thalamotomy lesioning on the efficacy and targeting of subsequent deep brain stimulation (DBS) in essential tremor (ET) patients.
• To determine optimal targeting strategies for both thalamotomy and rescue DBS to achieve durable tremor control and minimize adverse effects.

Main Methods:

• Case series of 3 ET patients undergoing bilateral DBS for tremor recurrence after thalamotomy.
• Analysis of microelectrode recording (MER) data comparing lesioned and non-lesioned ventral intermediate nucleus (VIM) sites.
• Evaluation of DBS stimulation parameters and clinical outcomes related to lesion location and VIM targeting.

Main Results:

• Thalamotomy lesions demonstrated reduced electrophysiological activity on MER and required less DBS charge density for tremor control, indicating irreversible effects.
• Tremor recurrence was associated with thalamotomy lesions missing the central VIM and dentato-rubro-thalamic tract.
• Ventral VIM stimulation provided the most tremor reduction in rescue DBS, while central VIM stimulation balanced efficacy and side effects.

Conclusions:

• Deep brain stimulation (DBS) is a safe and effective rescue therapy for essential tremor (ET) following thalamotomy failure, without necessitating re-targeting of the prior lesion.
• Prospective studies are recommended to refine initial DBS targeting (e.g., 2 mm anterior to standard VIM) and thalamotomy coordinates (e.g., 1 mm anterior, 1.2-1.5 mm superior) for improved outcomes.