In vivo Visualization of Pig Vagus Nerve "Vagotopy" Using Ultrasound

Area of Science:

• Neuromodulation
• Surgical Anatomy
• Medical Imaging

Background:

• Vagus nerve stimulating cuff placement relies on general anatomical landmarks, leading to limited patient specificity.
• Current methods result in side effects like neck muscle contractions due to imprecise stimulation of motor fibers.

Purpose of the Study:

• To evaluate the use of surgical pocket ultrasound for higher resolution imaging of the vagus nerve.
• To improve patient-specific electrode placement for vagus nerve stimulation.

Main Methods:

• High-resolution ultrasound was employed within the surgical pocket in a pig model.
• Ultrasound data was used to create 2-D and 3-D reconstructions and compared with histology.
• Naïve volunteers used ultrasound images to guide electrode placement away from motor fascicles.

Main Results:

• Surgical pocket ultrasound provided accurate 2-D and 3-D reconstructions of the cervical vagus nerve.
• Ultrasound allowed tracing of fascicle groupings from the nodose ganglia to the electrode placement site.
• Volunteers successfully placed electrodes away from motor nerve fascicles.

Conclusions:

• The surgical pocket offers a unique approach for high-resolution ultrasound of the vagus nerve.
• This technique enhances patient-specific electrode placement, optimizing neuromodulation outcomes.
• The method is adaptable for various neuromodulation targets to understand anatomical impacts on function.