Phrenic nerve stimulation for diaphragm pacing with a spinal cord stimulator: technical note

Area of Science:

• Neurology
• Medical Devices
• Respiratory Medicine

Background:

• Diaphragm pacing is an established treatment for central hypoventilation syndrome.
• Specialized diaphragm pacing devices are not widely available, particularly in Japan.
• Spinal cord stimulators, typically used for pain management, were repurposed for phrenic nerve stimulation.

Purpose of the Study:

• To evaluate the efficacy and feasibility of diaphragm pacing using a spinal cord stimulator as a compromise method.
• To assess the potential of this alternative approach for patients with chronic hypoventilation.

Main Methods:

• Four patients with chronic hypoventilation due to brainstem dysfunction received spinal cord stimulators.
• Stimulation electrodes were placed along the phrenic nerve, with the device implanted in the anterior chest.
• A cyclic stimulation mode was employed with specific parameters (1s ramp up, 2s on, 3s off, 150 µs pulse width, 21 Hz frequency), adjusting amplitude for adequate tidal volume and PaCO2 levels.

Main Results:

• All four patients experienced stable and sufficient ventilation over a mean follow-up of 8.3 months without complications.
• One patient with sleep apnea syndrome was weaned off a respirator, using the device nocturnally.
• Three patients transitioned from complete respirator dependence to daytime ambulation.

Conclusions:

• Diaphragm pacing using a spinal cord stimulator is a feasible treatment for central hypoventilation syndrome.
• This compromise method offers a viable alternative for managing chronic hypoventilation.
• While promising, longer-term follow-up is warranted to further confirm the durability and long-term benefits.