Chronic motor cortex stimulation in patients with thalamic pain

Area of Science:

• Neurology
• Neurosurgery
• Pain Management

Background:

• Thalamic pain, a debilitating neuropathic condition, often shows limited response to conventional treatments.
• Previous studies indicate thalamic relay nucleus stimulation yields suboptimal pain control in thalamic pain patients.
• Understanding deafferentation pain mechanisms is crucial for developing effective therapeutic strategies.

Purpose of the Study:

• To evaluate the efficacy of chronic precentral gyrus stimulation for treating thalamic pain.
• To compare the effectiveness of precentral gyrus stimulation with thalamic relay nucleus stimulation.
• To investigate the potential mechanisms underlying pain inhibition via cortical stimulation.

Main Methods:

• Eleven patients with thalamic pain underwent chronic stimulation of the precentral gyrus.
• Pain control was assessed during a 1-week test period, followed by system internalization in successful cases.
• Stimulation parameters (pulse duration, intensity) were optimized for pain inhibition without inducing muscle contraction.

Main Results:

• Excellent pain control was achieved in 73% of patients (8/11) with precentral gyrus stimulation, leading to system internalization.
• Postcentral gyrus stimulation showed no clear effect or exacerbated pain.
• Precentral stimulation efficacy was sustained long-term (>2 years) in 45% of patients, with gradual decrease in others.

Conclusions:

• Chronic precentral gyrus stimulation represents a promising therapeutic option for thalamic pain, offering significant and sustained pain relief.
• This method demonstrates superior outcomes compared to thalamic relay nucleus stimulation for thalamic pain.
• Cortical stimulation may inhibit deafferented nociceptive neurons by activating hypothetical fourth-order sensory neurons.