In This Section
Christopher Reeve &
Investigational Diaphragm Pacing Device
Questions & Answers
How does the new diaphragm pacing device work?
The device provides electrical stimulation to
the muscle and nerves that run through the diaphragm. When the muscle is
stimulated, it contracts, causing a vacuum-like effect in the chest cavity that
causes air to enter the lungs. When the contraction eases, the air is
expelled passively. This process is repeated 10 to 14 times per
minute. This is essentially the same process as normal breathing.
Why couldn't Mr. Reeve breathe on his own?
After a high cervical spinal cord injury,
signals sent from the brain can no longer flow through the spinal cord to
activate the respiratory muscles. As a result, his breathing muscles are
paralyzed. Mr. Reeve's injury was at the cervical (C2) level.
Consequently, he requires a mechanical ventilator to do the work of the
inspiratory muscles that are responsible for causing air to move into his
lungs.
How does the minimally invasive procedure work?
Surgeons create four dime-size holes in the
abdominal region, inserting tools (including a laparoscope) that allow them to
visualize the diaphragm muscle and place tiny electrodes in areas near the
phrenic nerves that control diaphragm contractions. A procedure called
"mapping" allows doctors to find specific areas where electrodes will
be most effective in stimulating the nerves. The electrodes are delivered
safely to those areas through a patented laparoscopic tool and implanted in the
muscle. The mapping techniques and electrode delivery tool were designed
and developed by the research team at University Hospitals of Cleveland
and Case Western Reserve University.
The electrodes are attached through wires under the skin to a small external
battery pack that electrically stimulates the muscle and the phrenic nerves,
causing the diaphragm to contract. Contraction of the diaphragm muscle
accounts for most of the air that inflates the lungs during normal, quiet
breathing.
How did Christopher Reeve qualify for this
investigational procedure?
The investigational diaphragm pacing system has
received FDA approval to be tested in ventilator-dependent patients who have
intact phrenic nerve function. Some spinal cord injuries result in
damaged phrenic nerves-those patients would not qualify for this study.
Mr. Reeve's phrenic nerve function is normal, as demonstrated in tests used to
qualify patients for this study. Those tests include fluoroscopic
examination of diaphragm movement and phrenic nerve conduction studies.
To view a form to be considered as a candidate for the diaphragm pacing system,
click here.
What are the costs of this procedure?
Currently, the procedures are being conducted
under an FDA protocol, with research funds covering the costs of the device and
its implantation. We hope to acquire enough funding support to implant
the device in 35 additional patients, a number we feel is necessary to
demonstrate effectiveness for chronic long-term use. We believe that once
we have FDA approval to market this diaphragm pacing system, it will be fully
reimbursed, given current reimbursement policies.
How much funding do you need to continue
development of this device?
Current funding from the Food and Drug
Administration and US Surgical will support the study of this pacing system in
5 patients. We estimate the cost associated with the further development,
clinical trial and devices for 35 additional patients may be two to three
million dollars.
Tell us about the first patient to undergo this
procedure.
The first patient was a 36-year old Ohio man who was injured
in an above-ground swimming pool accident in July, 1998. He suffered a C2
spinal cord injury. Approximately 1½ years after the injury, he underwent
the experimental laparoscopic surgery at University Hospitals Case Medical Center. The
proper placement of the electrodes required a secondary surgical procedure
several months later. Over several months of diaphragm conditioning, he
was weaned off mechanical ventilation, and has been independent of the
ventilator for more than two years. This has allowed him to speak more
normally, has improved his sense of smell, and increased his mobility.
How many patients have undergone this procedure?
Mr. Reeve is the third patient to undergo this
procedure. In the case of the second patient considered for the study, the
health of the phrenic nerves and the diaphragm muscle were not adequate to
support the pacing system.
What kind of rehabilitation is involved after
surgical placement of the device?
After one to two weeks following the surgical
procedure (during which time the electrodes stabilize in the diaphragm and
wounds have begun to heal), the patient undergoes a series of conditioning
exercises in our clinical research center. Each implanted electrode
is individually evaluated to monitor the volume of air inspired by diaphragm
contractions. The diaphragm pacing program is set at a point that is
effective and comfortable for the patient. Following this evaluation,
diaphragm pacing parameters are set for his conditioning program, which is
expected to last several weeks.
What happens to Mr. Reeve
if the device malfunctions?
The tracheostomy is still in place, and if Mr.
Reeve experiences any distress at all, he can easily be placed back on the
mechanical ventilator.
Have you published any of your research?
During the last decade, several articles have
appeared in scientific publications documenting the development of our pacing
system and the laparoscopic tools required in surgery. Most recently, the
case report on our first patient was published in the American Journal of
Respiratory and Critical Care Medicine (Vol 166, pp 1604-1606). Also, Dr.
Onders presented this research at the Annual Scientific Session of the Society
of American Gastrointestinal Endoscopic Surgeons (SAGES) in April, 2001 in St. Louis.
Dr. DiMarco presented this research at the International Thoracic Society
Meeting in May, 2001.
It should be noted that although Christopher
Reeve is the Chairman of the Board of the Christopher Reeve Paralysis
Foundation (CRPF), the CRPF does not endorse this study. CRPF was not involved
in any way in Mr. Reeve's participation in this study, including the funding of
it.
For more information about Functional Electrical
Stimulation (FES), go to http://fescenter.case.edu/.
The Cleveland FES Center develops FES solutions to some of the problems facing individuals
with paralysis due to central nervous system disorders like spinal cord injury
or stroke.
|