Straightening Out Koala Kinks

Scoliosis is the medical term for curvature of the spine. Long recognised as a problem in children, it is not what you associate with koalas, but that link has been the subject of Emily Milbourne's honours project.

Emily is the winner of the Raymond Last Scholarship, offered jointly by Adelaide University and the Royal Zoological Society of South Australia for a study in comparative anatomy that is of interest to both organisations. The scholarship is funded from Professor Last's bequest in honour of the renowned Adelaide anatomist Professor Frederick Wood-Jones, who wrote the first authoritative book on the mammals of South Australia.

Emily is well placed to undertake such research. While studying in the Department of Anatomical Sciences, she is also a part-time animal keeper at Adelaide Zoo.

"In my undergraduate degree, I majored in zoology and anatomical sciences," said Emily. "I always wanted to work with animals, so it's a nice job to have on the side."

"I am now applying to do chiropractic in Melbourne and Sydney," said Emily. "Then I hope to go on to do animal chiropractic which is a 1-year post graduate the year after that. It would be exciting to see chiropractic introduced into zoos," she said.

Scoliosis in koalas sounds a fairly obscure study, so how does one begin?

"When I was looking for an Honours project, Professor Maciej Henneberg suggested a study of the koala spine," said Emily. "Even the normal anatomy of koalas is not fully described, as far as I can tell," she said. "Professor Wood Jones and others have described parts of it, especially the skull and head musculature, but the back and limb anatomy has not been so well described. I am dealing with the normal anatomy first, and then going on to describe scoliotic animals."

Scoliosis in koalas and humans seems to take different forms. "If you showed a scoliotic koala to a doctor, they would probably not describe it as scoliosis in human terms," said Emily. "The spine, instead of being straight, develops a sharp angle to one side. It's as though the animal had been snapped by bending its head down to its feet," she said.

No koalas are being euthanased for the study. Cleland Wildlife Park, where koalas are permanently on show, has a number of cadavers from natural deaths, dog attacks and car accidents. These bodies are being made available for the research, and they include some very old animals, in which scoliosis can be more pronounced.

"The president of the Port MacQuarie Koala Hospital in New South Wales has also regularly sent information on scoliotic koalas," said Emily, "Four so far, and all old," she said.

"The koala I am currently studying was ten years old when it died," said Emily. It showed problems at 1-2 years, some difficulties with movement and pain now and then, especially when it was old," she said. "But because it was in captivity, it would not have had the difficulties of a wild koala, which would have to be agile on the ground to avoid predators and much more active in getting food."

"Koalas are quadrupeds, not bipeds like us" said Emily, "But just as we sit upright, they spend at least 19 hours each day sitting upright with a spine that isn't designed for that. A sitting koala tends to put all the pressure on its sacrum, so it uses its spine a lot, even leaning back on tree branches," she said.

"Gravity acts very differently on horizontal and vertical spines, so when a quadruped sits upright, it is going to change the forces acting on its spine," said Emily. "I can imagine a lot of discomfort and even pain if they are scoliotic."

"It is very difficult to get reliable information on how many wild koalas have back problems," said Dr Greg Johnston, the Society's Senior Research Scientist, and an Honorary Research Fellow at the Department of Anatomical Sciences. Professor Maciej Henneberg and he are joint supervisors of the project.

"The best figures suggest that up to 5% of koalas may be afflicted," said Dr Johnston. "Emily's work will tell us how serious a problem the disease is and may suggest better modes of treatment for them."

Adelaide Zoo plans to create a new koala habitat and exhibit in the near future. Emily hopes that if her work shows that scoliosis has an environmental origin, it may assist zoos in designing better koala habitats of this kind, but she sees other benefits, too.

"Since the koala is one of Australia's best known animals, it is good to have a description of its basic anatomy that other researchers can use, and which will help them detect abnormalities," said Emily. "In terms of scoliosis, I don't think that my research will determine what causes it, but because it hasn't been researched before, it should provides a starting point for others who may find the cause, or any genetic links."

Photos available at: http://www.adelaide.edu.au/pr/media/photos/2001/