Thursday, April 29, 2010
Medical advances making it possible for dogs like Cassidy to romp on all four legs.
An injury prevented Juniper from walking normally. Frostbite damaged the hind legs of Meadow. And Andre gnawed off his paws to escape from a wolf trap.
Until a few years ago, there wasn't much hope for these and other disabled animals of ever leading normal lives again. But thanks to advancements in veterinary medicine, and the small but growing field of animal prosthetics, it's now possible for pets and farm animals with missing limbs to walk, run and romp on all four legs.
Cassidy, a shepherd mix, with a caramel-colored coat, was recently outfitted with a carbon fiber leg similar to ones that amputee runners use.
"We just came back from the beach and he's able to run all day," said Cassidy's owner, Steve Posovsky, a retired dentist in Delray Beach, Fla.
The adopted stray -- found wandering the streets of the Bronx on three legs -- is a medical pioneer, becoming the first dog to successfully undergo osseointegration orthopedic surgery, a procedure that may one day benefit humans.
During the four-hour operation, a titanium implant was inserted into Cassidy's right hind leg bone -- designed by veterinarian Denis Marcellin-Little and his colleagues at North Carolina State University in Raleigh -- so that a custom prosthetic limb could later be screwed into the visible tip. The result is an artificial leg that behaves more like a natural limb.
"It's not that different from a total joint replacement," said Marcellin-Little of the surgery. "And, clearly, we have a lot of experience fixing joint prosthetics to bone. That's done in hundreds of thousands of people each year worldwide."
Since Cassidy's surgery in July 2008, a handful of veterinarians in the United States and Europe have used osseointegration to replace limbs of other family dogs and cats.
Marcellin-Little, a professor of orthopedics, currently has three patients -- all dogs that will soon undergo the $7,000 procedure that replaces a missing lower extremity of an otherwise healthy leg.
Entire limbs cannot be replaced, he said.
In Cassidy's case, it's taken 18 months between the surgery and receiving his permanent prosthetic leg in March.
"It's not simple, cheap or quick," Marcellin-Little said of the process.
That's because all equipment is designed and hand-built for each patient, and the experimental surgery must be rehearsed beforehand to make sure it goes smoothly.
It takes around three months of healing time before weight is put on the leg; the animal then must re-learn how to walk on all four feet.
For six weeks, Posovsky patiently helped Cassidy inch across the bedroom, putting one leg in front of the other. The hours upon hours of training finally paid off when one morning Cassidy began to walk on his own.
For most animal owners, externally attached prosthetics are a faster, less-expensive option.
OrthoPets, in Denver, manufactures prosthetics and braces for about 1,200 animals worldwide each year. Most are dogs, but they've also worked with cats, cows, birds, llamas, horses, even an orangutan.
"We joke that if it has an appendage and a heartbeat, we can usually help out," said Amy Kaufmann.
She started the business six years ago with her husband, Martin, who previously worked in the human prosthetics field.
The external prosthetics are built to "last a lifetime" by using tough industrial grade plastic, said Kaufmann. To combat chafing and irritation the devices are lined with special color-changing foam that turns black, alerting owners if a problem arises.
For an animal to be outfitted with an artificial limb, which is attached with straps, Kaufmann said front legs must still have the elbow joint and part of the radius and ulna. The knee joint, as well as part of the tibia and fibula, must be present on rear legs.
Prosthetics for cats and dogs cost between $600 and $800. The price for larger animals, such as cows, llamas and horses, ranges from $800 to $2,000.
For Cassidy, the three-legged shepherd, even the most sophisticated external prosthetic didn't work. Marcellin-Little made two different artificial limbs for him. But because of Cassidy's odd-shaped leg, the devices didn't stay on.
That's when Posovsky and his wife, Susan, decided to move forward with osseointegration, in hopes of giving their dog the joy of being able to go for long walks with them on the beach.
"Cassidy had every reason not to be a nice dog, and have an attitude," said Posovsky of the practically hairless mutt he adopted from the pound. "But this dog -- you can't even make him mad if you tried. That's how sweet he is. He is just the most wonderful, deserving, loving animal there is."
Tuesday, April 27, 2010
It may give doctors new tool in treating and managing heart disease, experts say.
Adding a computed tomography test to measure calcium in coronary arteries improves predictions of future heart disease, a new study finds, but no one knows yet whether it's worth the cost and risk due to radiation exposure.
"This kind of evidence gives encouragement to go on and do additional testing, but it shouldn't convince us that this test should be done routinely," said Dr. Philip Greenland, a professor of preventive medicine at Northwestern University Feinberg School of Medicine, and a member of the team reporting the study in the April 28 issue of the Journal of the American Medical Association.
Computed tomography uses X-rays to get a detailed picture of heart structure. Its use in diagnosing existing heart disease has become controversial because X-ray exposure increases the risk of cancer. The new study of nearly 6,000 healthy Americans was done to see whether the technique could improve the predictive power of existing cardiac risk factors such as high blood pressure, high cholesterol and obesity.
The study began in July 2000 and ran through May 2008. It used two models to predict the five-year risk of a heart attack, resuscitated cardiac arrest or death from coronary heart disease: the traditional risk factors; or those risk factors plus the coronary artery calcium score.
At 5.8 years, the participants had experienced 209 coronary heart disease problems and 122 "major events" -- that is, heart attacks, deaths from coronary heart disease, or cardiac arrest followed by resuscitation.
The second model, which used the regular risk factors plus the calcium scan, was able to predict an additional 23 percent of the participants who would go on to experience a harmful cardiovascular event. In addition, 13 percent the model reclassified as low-risk did not experience an adverse event.
But does that added predictive power make a difference in terms of saving lives and reducing unnecessary treatment?
"We didn't look at that," Greenland said. "What we can say here is that additional testing looks like it improves prediction. Whether it improves clinical outcome requires a different kind of study."
The first steps toward such a study have been taken. "We are in discussions with the National Heart, Lung, and Blood Institute and have been encouraged to submit a proposal," Greenland said.
Such a study might involve tens of thousands of participants and cost over $100 million, said Dr. Andrew J. Einstein, director of cardiac computed tomography research at Columbia University Medical Center in New York City.
The study would aim at determining whether more intensive treatment of traditional risk factors would improve survival of people classified as high-risk by the coronary artery calcium score. "No study has compared patients who had intensive preventive therapy with those who didn't and see if it makes a difference in terms of the number of heart attacks people have," Einstein said. "That study would be the ideal."
Such a trial needn't be as expensive as Einstein estimates, Greenland said. He puts the cost at "between $29 million and $50 million" and notes that the U.S. Institute of Medicine lists that kind of trial among the top 100 that should be done using funds provided for comparative effectiveness research in the newly approved health care program.
Cancer risk and cost are also parts of the equation. A well-controlled computed tomography scan gives about twice the radiation exposure as a mammogram, Greenland said. A new large-scale trial could show whether the added risk is justified by the number of lives saved, and the same is true of the cost, estimated to run between $200 and $600 per scan.
"Concern about radiation for any individual is minimal, and the cancer issue is 20 years down the line," said Dr. Joseph Ladapo, a clinical fellow in medicine at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston. Incidental findings of a scan, such as possible lung problems, can also help justify its widespread use, Ladapo said.
But the time for widespread use has not arrived, Greenland noted. The new study results "are not an endorsement for screening," he said.
Monday, April 26, 2010
Finding could help the elderly or sick who lose interest in food, researchers say.
Laughing can boost the appetite in the same way that exercise does, a finding that could help people eat more when they're sick or depressed, a researcher says.
"The value of the research is that it may provide those who are health-care providers with new insights and understandings and thus further potential options for patients who cannot use physical activity to normalize or enhance their appetite," Dr. Lee S. Berk, a preventive care specialist and psycho-neuro-immunology researcher at Loma Linda University's Schools of Allied Health and Medicine in California said in a news release from the Federation of American Societies for Experimental Biology.
Berk and a colleague have studied laughter and contend that "Laughercise" -- their term for repetitive "mirthful laughter" -- boosts the immune system.
In the study, Berk and colleagues recruited 14 volunteers to watch different kinds of videos -- funny or distressing -- over a three-week period.
Those who watched funny videos experienced changes in hormone levels that are linked to greater appetite. The changes are similar to those experienced by people when they exercise moderately.
"We are finally starting to realize that our everyday behaviors and emotions are modulating our bodies in many ways," Berk said.
The study was to be presented at the annual Experimental Biology meeting, April 24 to 28, in Anaheim, Calif.
