A beloved fur seal named Ziggy Star has survived a risky form of brain surgery—the first of its kind. In spite of the uncertainty, however, Ziggy Star managed to pull through and thrive.
Ziggy was emaciated when she first came to Mystic Aquarium. [Photo by Ingrid Overgard]
Ziggy Star, an adult female fur seal, was taken in by Mystic Aquarium around four years ago. She was found stranded on the California coast, noticeably thin and ill. MRI scans showed that Ziggy had neurologic abnormalities, prompting federal authorities to decide that she cannot be released back into the wild. The seal’s symptoms continued to progress, her cognitive functions began to worsen, and she even began experiencing seizures despite receiving treatment.
"I wouldn't have given her next week," says Ane Uriarte, a Tufts University neurosurgeon. Non-surgical ways to control the seizures weren’t working, and liquid began filling her brain in a condition called hydrocephalus.
These days, Ziggy is eating well, gaining weight, and has even started swimming again. However, her road to recovery was a long one.
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"The MRI taken recently by our team showed that the brain was disappearing due to the excess fluid, and it was significantly worse than the last study four years ago," Uriarte says. "After discussion with Mystic's veterinary team, we determined the best option to prevent further deterioration of the brain and to improve Ziggy's symptoms was to surgically place a shunt to drain the excess fluid, relieving some of the pressure on the brain."
However, the procedure wasn’t as simple as Uriarte put it. Hydrocephalus was common in cats and dogs, but there have been no documented cases in which the condition was surgically treated in pinnipeds, or animals such as seals, walruses, and sea lions. Thus, the surgical team drew information from their experiences in treating other animals as well as from x-rays of Ziggy’s skeleton, making this the first documented hydrocephalus surgery on a seal. The surgeons were able to determine where to place the shunt, which is basically a narrow tube, in Ziggy’s skull.
Anesthetizing the seal for surgery was also a challenge. Marine mammals have “dive reflexes” that cause changes in heart rate, blood pressure, and breathing when anesthesia is involved. Thus, the surgical team had to move fast, since Ziggy was prone to losing her breathing reflex the longer she was anesthetized.
Ziggy in surgery [Photo by Mystic Aquarium]
The team inserted a small valve into Ziggy’s brain, then attached the valve to a tube that drains fluid from her brain into her abdomen. The fluid, luckily, is harmless and can be absorbed by her body. CT scans confirmed that the shunt was placed correctly in Ziggy’s skull.
While Ziggy is now thriving, she had a longer recovery period than normal due to seizure activity, which was fortunately successfully handled. Once she was stable, she was able to return to Mystic Aquarium.
One thing that still remains unknown is how Ziggy developed her condition. It’s unlikely that she was born with it, since if she had been, she would not have survived to adulthood. She possibly suffered head trauma, though it’s likely that the exact cause of her condition will remain unknown.
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