Chronic motor cortex stimulation for phantom limb pain: a functional magnetic resonance imaging study: technical case...

Area of Science:

• Neurosurgery
• Pain Management
• Neuroimaging

Background:

• Chronic motor cortex stimulation (CMCS) is effective for central and neuropathic trigeminal pain.
• Phantom limb pain (PLP) and phenomena present significant challenges in amputee patients.
• Understanding the neurobiological underpinnings of PLP is crucial for developing targeted therapies.

Purpose of the Study:

• To evaluate the efficacy of CMCS in a patient with phantom limb pain.
• To utilize functional magnetic resonance imaging (fMRI) for guiding electrode placement in CMCS for PLP.
• To investigate the cortical mechanisms involved in pain control and phantom limb phenomena.

Main Methods:

• A 45-year-old male amputee with severe phantom limb pain and phenomena underwent chronic motor cortex stimulation.
• Pre- and postoperative fMRI guided electrode placement using an infrared-based frameless stereotactic device.
• fMRI assessed cortical activation in response to virtual amputated hand movements and during stimulation.

Main Results:

• Successful pain control was achieved, with a 70% reduction in phantom limb pain on the visual analog scale.
• fMRI identified contralateral primary motor cortex activation during virtual finger movements.
• Postoperative fMRI revealed inhibitory effects on the sensorimotor cortex and contralateral motor/sensory cortices under stimulation.

Conclusions:

• Chronic motor cortex stimulation is a viable treatment for phantom limb pain and phenomena.
• fMRI-guided electrode placement enhances surgical precision for CMCS in PLP.
• fMRI provides insights into pain modulation and cortical reorganization in response to neuromodulation.