NEW BREATHING DEVICE RESULT OF CWRU, UHC, VA RESEARCH
07 February 2007 - Case Western Reserve University

"The design of this device spans decades and stems from 30 years of research under generous funding from the Department of Veterans Affairs, which has been committed to the University and the shared mission to advance applied neural control systems technology," said Thomas Mortimer, the lead researcher and professor emeritus in the department of biomedical engineering.

Mortimer developed the device with the help of biomedical engineering graduate students. The device has been successfully implanted in two human subjects, including Reeve, with the help of Anthony F. DiMarco and Raymond P. Onders at UHC and with grant funding from the VA, the Food and Drug Administration and U.S. Surgery Corporation.

Early pioneers in biomedical engineering began work on the device in 1980, leading to an approach that included placing electrodes within a required distance of the phrenic nerve to induce inspiration. By 1984, a renewed approach utilized a laparoscope to peer inside the diaphragm.

"The turning point in the evolution of this respiratory device came in 1987 when CWRU researchers developed an electrode that could carry a signal to the muscle and induce breathing. The problem was in locating the very limited region around the phrenic nerve that generated a successful breathing response," Mortimer said.

In 1990, the researchers created a device that made it possible to staple the electrode to the diaphragm. By 1996, they had developed a custom implant tool, which was successful at implanting the intramuscular electrodes in the responsive zone, or "motor point," surrounding the phrenic nerve. They utilized a computer to map the precise location of the spot where the electrode must be positioned to stimulate breathing.

"Today, the method we have developed to activate the diaphragm reduces the risk of phrenic nerve injury, requires less time to implant than previous technology and can be performed as an outpatient surgical procedure," Mortimer said. "Compared to conventional ventilator therapy, this new device has the potential to reduce a patient's time spent on the ventilator, increase self-induced breathing and a sense of well-being. Patients must still have a ventilator because they remain at risk that the device may fail but the device itself can significantly increase their quality of life.

"The current standard for patients with spinal cord injuries above the third and fifth cervical vertebrae region is a ventilator to allow them to breathe," Mortimer continued. "However, the majority of patients afflicted with quadriplegia would prefer to live more independently. After 30 years of committed research, this respiratory assist device has emerged as a minimally invasive alternative to the ventilator. Our new device is designed to work in synergy with a laparoscope and looks to offer a fresh new solution."

Anthony Ignagni, a biomedical engineering alumnus, Mortimer, Onders and DiMarco and their research team are establishing a business approach for the new device, looking into the viability of reproducing it for other patients and providing backup devices for those that may fail in patients over time.

"We need to be able to maintain the production of the device for a prolonged period of time," Mortimer said. "Our VA funding provided the necessary support and brings us closer to a viable treatment option."

Mortimer is confident that the new device will be of interest to clinicians in the medical field, who strive to improve the therapeutic outcome for patients, as well as the patients themselves.

Onders and DiMarco lead the clinical trials at UHC.

The device is designed for those who suffer chronic respiratory insufficiency resulting from high quadriplegia above the third and fifth cervical vertebrae region in the spinal cord but is exclusively designed for cases in which the phrenic nerve remains intact. The phrenic nerve originates in the upper half of the spinal cord, between the third and fifth cervical vertebrae and extends to stimulate the diaphragm muscle. It is responsible for transmitting the nerve impulses to the diaphragm, which cause it to contract and expand, facilitating breathing.

"The device utilizes intramuscular electrodes that are surgically implanted into the diaphragm and connected to an electrical stimulator causing the phrenic nerve to release neurotransmitters," Mortimer said. "These neurotransmitters cause the diaphragm to contract, which brings about inspiration."

Researchers say that this new technology can be life-altering when it is successfully implanted into a patient who depends on a ventilator to breathe. The ventilator, they say, is noisy and requires patients to wait for a breath of air whereas the new device uses the body's respiratory system to draw and release air.

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