About Spinal Cord Injury and the Avery Diaphragm Pacing System

Quadriplegia, also known as tetraplegia, is the loss of voluntary movement and sensation in all four extremities, and usually results from a cervical spinal cord injury (SCI). Other conditions, such as a brain stem lesion or spinal meningitis, may also result in quadriplegia.

The phrenic nerve originates at C3 through C5 and is the neurological pathway between the brain and the diaphragm. Injuries that occur at or above C4 can interrupt these pathways and render the patient dependent on ventilatory assistance. Immediately following injury, this assistance is provided by a mechanical ventilator. After the patient is neurologically and orthopedically stable and cannot be weaned from mechanical ventilation, a diaphragm pacing system should be considered.

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Quadriplegia and the Need for Ventilatory Assistance

Quadriplegia is the loss of voluntary movement and sensation in all four extremities, and usually results from a cervical spinal cord injury (SCI). Other conditions, such as a brain stem lesion or spinal meningitis, may also result in quadriplegia which is also known as tetraplegia.

An SCI can be complete or incomplete. The term incomplete indicates that the patient has some sensory or motor function below the injury level. There are seven cervical vertebrae and eight cervical nerves, identified as C1 through C8. The level of injury directly correlates to the patients abilities and needs.

  • Patients with an injury or disease at C1, C2, and higher may have little or no movement of their head and neck, and may be entirely dependent on ventilatory assistance for breathing.
  • Patients with an injury at C3 usually have control of their head and neck and are occasionally weaned from ventilatory assistance.
  • Patients with an injury at C4 usually have control of their head and neck, some shoulder movement and are often weaned from ventilatory assistance.
  • Patients with injuries at C5 and lower have control of their head and neck, progressively more control of their arms and hands and are rarely in need of ventilatory assistance.
  • Patients with injuries below the cervical spine have full function in the upper extremities, which is classified as paraplegia. Paraplegics do not lose control of respiratory drive.

How a Diaphragm Pacing System Works

A diaphragm pacing system consists of surgically implanted receivers and electrodes and an external transmitter with antennas which are worn directly over the implanted receivers.

The external transmitter and antennas send radiofrequency energy to the implanted receivers just under the skin. The receivers then convert the radio waves into stimulating pulses.

These pulses are then sent down the electrodes to the phrenic nerves, causing the diaphragms to contract. This contraction causes inhalation of air. When the pulses stop, the diaphragms relax and exhalation occurs. Repetition of this series of pulses produces a normal breathing pattern.

Who Is a Candidate for the Diaphragm Pacing System?

A diaphragm pacing system can provide ventilatory support for patients with chronic respiratory insufficiency whose diaphragm, lungs, and phrenic nerves have residual function. Typically, these patients have high spinal cord injuries, central sleep apnea or other central neurological disorders or a paralyzed diaphragm.

See a Comparison of the Avery Device

How does the Avery Diaphragm Pacemaker compare to the competitor device for Spinal Cord Injury? See the comparison here:

See the Comparison

Advantages over Mechanical Ventilation

Diaphragm Pacing Systems provide many advantages for Quadriplegics over mechanical ventilation (Positive Pressure Ventilation, or PPV). Some advantages include:

  • Lower risk of upper airway infections due to reduction in suctioning, elimination of external humidifier and ventilator circuits, and potential removal of tracheostomy tube in some patients where appropriate
  • More natural breathing function that is physiologically more accurate and comfortable
  • Compact design without bulky tubing and batteries, which allows for greatly increased mobility and INDEPENDENCE! (some of our patients have even gone sky diving, rode jet-skis, are able to go in a pool (water therapy), attended Broadway shows, and so much more!)
  • Superior sensory and related motor functions, including improved sense of smell, ease of eating and drinking, and more natural breathing and speech patterns
  • Significant short and long term cost savings – Diaphragm Pacing Systems typically pay for themselves in roughly two years, with an average savings of $20,000 per year thereafter. The patient no longer needs to be tethered to a ventilator in an ICU bed or acute rehabilitation facility, saving the hospital and insurance company thousands of dollars each day. For the patient, typically their cost consists of the purchase of 9V batteries and some tape for the antenna.

For More Information

The Diaphragm Pacing System may be an option for patients with Quadriplegia or SCI to improve their quality of life and decrease difficulties caused as a result of care. For more information, please call us at 631-864-1600, or click the “request info” button below and fill out the contact form. We would be happy to get you more information about how the diaphragm pacing system may help, and connect you with a physician familiar with the device in your area if needed.

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