May 03, 2005 – Electronic device gives ALS patient a major assist
By: Diana Keough
Four weeks ago, Susan Larson became the first patient with Lou Gehrig's disease to have an electronic device implanted into her diaphragm to prolong her life. Last week, the 49-year-old former nurse from Rogers, Ark., learned the doctor's hunch was correct. The device is working.
"Her diaphragm muscles are definitely thicker than they were four weeks ago," said Dr. Raymond Onders, Larson's surgeon and director of minimally invasive surgery at University Hospitals. "Diaphragm muscles are like biceps. If you work them, they'll get thicker."
Onders said tests on Larson indicate the device moves more muscle than she is capable of doing on her own.
"That means we may be preventing muscle from dying," Onders said. He says this might translate to an additional 10-month survival for Larson.
Larson had Lou Gehrig's disease (formally known as amyotrophic lateral sclerosis, or ALS) diagnosed three years ago. Before her disease, she played tennis and golf and worked as a pediatric nurse specializing in autism. She can no longer move her arms or legs, is fed through a port in her stomach and communicates with cryptic guttural moans of "Ah" and "Ooh" and jerks of her head that her husband of 27 years, Lonnie, interprets.
In between Monday's tests, Larson showed off pictures of her daughter, Stephanie, 17, and her date, taken before last weekend's prom.
At this point, Larson can still breathe on her own, though recent tests showed her ability has dropped a few percentage points. Among ALS patients and their loved ones, it's no secret that life expectancy is nine months once lung capacity dips under 50 percent. Larson's score Monday was 48 percent.
"It's important to implant earlier than later," said Onders. "These past four weeks, Susan's been able to work the diaphragm muscle to create some reserve so that when her health deteriorates, she can draw on that reserve."
In March, Onders placed four electrodes in Larson's diaphragm and attached them through wires under the skin to a small external battery pack. The device electrically stimulates the muscle and phrenic nerves, causing the muscles to contract and air to enter the lungs. Following surgery, Larson "trained" with the device - letting it work and pulsate her diaphragm muscles - for 30 minutes, five times a day at home in Arkansas.
"Working this hard has helped Sue with her attitude and how she approaches each day," said Lonnie. "Sue feels like the device is helping her."
Onders said the theory is simple: As a patient's health deteriorates, the pacing device makes the diaphragm move more than the patient can on his own, so he can continue to breathe.
"We'll be able to control something she no longer can," Onders said. No surgery can change the natural outcome of the disease, but it will more than likely prolong the life of ALS patients.
At the time of Larson's implantation, Onders was unsure if ALS patients could tolerate the device or if it would make any difference. He has performed this same surgery successfully on 17 patients with spinal cord injuries, including actor Christopher Reeve, two years ago. Trying it in ALS patients was just a hunch, he said.
Diaphragm muscles in spinal cord patients need to be jump-started; in ALS patients, the motor neurons within the muscles die. (The diaphragm contains thousands of motor neurons.) Onders hoped the electrode stimulation would allow functioning motor neurons to continue to work as the surrounding neurons die. For now, he said, he doesn't know if the device is saving neurons.
Since Larson's surgery, Onders has implanted the device in two other ALS patients whose disease, he said, is progressing more rapidly than Larson's.
"In rapidly advancing patients, we hope this device gives them four additional months," Onders said, acknowledging that he's not completely sure.
To qualify for the diaphragm-pacing device, Onders said, ALS patients must be over 18, have at least a 50 percent lung capacity, have an adequate social-support network and be willing to come to Cleveland.
Every year, an estimated 5,600 Americans are diagnosed with ALS, a rapidly progressing muscle disorder that attacks nerve cells responsible for controlling voluntary muscles. As the disease runs its course, patients lose the ability to move their arms, legs and body. When muscles in the diaphragm and chest fail, patients can no longer breathe without help from a ventilator. Most ALS patients die of respiratory failure, eventually suffocating, usually within three to five years from the onset of symptoms. There is no cure.
Larson decided she would never go on a ventilator, her husband said.
"Despite the good news, Susan still feels her time is getting pretty short," he said. She doesn't feel as though the pacing device will dramatically improve the quality of her life or even extend it for several years.
"She's just hoping it might give her another six months," he said.
The Larsons have three children. Lonnie said several major events are planned for next year: Their son Trent, 24, is trying to start a business; Nicholas, 25, plans to marry in May - the same month Stephanie graduates from high school.
"Her goal is to make it to both," Lonnie said.