A Potential 'Dream Come True' for Cats — and Harbor Seals?
This common urinary tract issue affects harbor seals & cats, too. The life of Hermes the harbor seal was liked saved by this innovative therapy, & now a similar technology is being trialed in cats...
STORY AT-A-GLANCE
Hermes the harbor seal, who resides at the Vancouver Aquarium in British Columbia, is receiving innovative care for his kidney stones — a common problem in seals
The seal has undergone a noninvasive technique called burst wave lithotripsy that uses focused ultrasound pulses to pulverize the stones, and is doing well; the procedure will need to be repeated to treat additional stones
Burst wave lithotripsy is also being trialed in cats with kidney stones at the University of Minnesota College of Veterinary Medicine
Not long ago, staff at the Vancouver Aquarium in British Columbia noticed that one of their residents, Hermes, was spending more time floating in the water, or hunched over. He was also eating less and seemed to be straining to urinate. It was clear the 23-year-old harbor seal had abdominal pain.
Ultrasound imaging confirmed Hermes had a common problem in seals — kidney stones. The stones were on both sides of his complex kidney structure, and aquarium staff knew from experience the condition would be difficult to treat.
Hermes Undergoes Two Different Procedures
As a measure of just how complex Hermes’ treatment was expected to be, veterinarians at the aquarium, led by Dr. Martin Haulena, head veterinarian and director of animal health, teamed up with urologists from Vancouver General Hospital, using facilities at the University of British Columbia Centre for Comparative Medicine (CCM).
Hermes was transported to the CCM, and while anesthetized, underwent two procedures. One involved a fluoroscope-guided endoscopy in a failed attempt to remove stones from one kidney; the second procedure, performed on the other kidney, was a noninvasive technique called burst wave lithotripsy that uses focused ultrasound pulses to pulverize the stones.
Burst wave lithotripsy is currently being studied in human patients. The device, called a SonoMotion Break Wave system, uses ultrasound imaging to direct delivery of ultrasound pulses to the target, which in Hermes’ case, was kidney stones. The seal had several stones larger than 1 centimeter in diameter, with some larger than 2 centimeters in diameter, and the burst wave lithotripsy broke many of those stones into fragments of 1 millimeter or less.
Per Haulena, after the procedure Hermes had some cramping and abdominal discomfort for a few days, probably because he was passing the broken stone fragments, but has since recovered. He’ll need to undergo future burst wave lithotripsy procedures to treat the remaining stones.
"We were pleased to see that Break Wave technology successfully broke up several stones in the left kidney which was clearly evident in real time," Haulena told online newsletter Vancouver is Awesome. "Hermes has recovered well from the procedure and is extremely comfortable. A follow-up CT exam will help guide further treatment."1
Potential ‘Dream Come True’ for Cats With Kidney Stones
Burst wave lithotripsy is a successor to shock wave lithotripsy, a similar procedure used to break up kidney stones in humans that is successful only about 60% of the time. The SonoMotion technology has been used to treat over 40 human patients in the U.S. and Canada, with good results, according to the company’s chief technology officer.
There is currently a clinical trial underway at the University of Minnesota College of Veterinary Medicine using burst wave lithotripsy to break up ureteral stones in cats. Dr. Eva Furrow, an associate professor in the Department of Clinical Veterinary Sciences, is leading the study and says early tests showed the machine can fragment calcium oxalate stones in cats in a water bath in 10 to 50 minutes.
Furrow’s team also plans to test the device on up to three cats with kidney stones to ensure the treatment doesn’t cause any major complications, followed by a second phase involving seven cats.
According to Dr. Jody Lulich, director of the University of Minnesota Urolith Center and a member of the research team, the new device "delivers focused ultrasound in short bursts at high rates and low peak pressures, and delivery is safer and more tolerable than typical shock wave lithotripsy."2
Furrow believes that if the new technology works, it could save many cats’ lives. Intravenous (IV) fluids and medications are effective in only about 15% of cats with stones. Surgery is expensive, and subcutaneous ureteral bypass devices (artificial ureters) must be flushed and cleaned and can become clogged with minerals.
Furrow told the American Veterinary Medical Association (AVMA) it would be a dream come true if the burst wave lithotripsy works in cats, and she hopes it someday becomes widely available to veterinarians.
Meanwhile, back at the Vancouver Aquarium, Haulena believes the technology could be especially helpful in treating animals with complicated kidney anatomy, including cetaceans, pinnipeds, cattle, and certain desert animals.
5 Fast Facts About Harbor Seals
From the National Park Service:3
Harbor seals are estimated to reach an average lifespan of 40 years in the wild. In captivity, the longest recorded lifespan was 47.6 years.
Harbor seal pups can swim at birth and can dive for up to two minutes when they are only two to three days old.
Harbor seals can dive to depths of 1,400 feet and remain underwater for nearly 30 minutes without resurfacing.
Their sensitive whiskers acoustically detect sound waves, which is useful for catching prey.
Unlike other pinnipeds, harbor seals are not sexually dimorphic, meaning there is no significant difference is size between females and males.
Healthypets Disclaimer: This information is for educational purposes only and is not intended to replace the advice of your own veterinarian or doctor. Dr. Karen Becker cannot answer specific questions about your pet's medical issues or make medical recommendations for your pet without first establishing a veterinarian-client-patient relationship. Your pet's medical protocol should be given by your holistic veterinarian.