SM & CM % in Cavaliers

[frecklesmom]

Have there been any studies that have shown less incidence of SM & CM in Cavaliers? I happened on this one ( small numbers) and thought that the % seemed to be close and then, with all discussion that the % is wrong ( not here) I wondered about any other studies that might have shown a difference.

ABSTRACT


Objectives: The objectives of the study were (1) to report the incidence of Chiari-like malformation and syringomyelia in a normal French cavalier King Charles spaniel breeding population; (2) to precise the standard computed tomography dimensions of the caudal fossa and (3) to investigate the use of ultrasonography in diagnosis of this syndrome.
Methods: Clinically normal adult cavalier King Charles spaniel underwent ultrasonographic examination of the spinal cord and caudal fossa. Computed tomography was used to measure the caudal fossa and magnetic resonance imaging allowed syringomyelia and cerebellar herniation identification.
Results: Of the 16 dogs in the study, seven had syringomyelia (43·7 per cent). All dogs had cerebellar herniation, suggesting Chiari-like malformation and also a tendency to occipital dysplasia. Computed tomography measurements of the caudal fossa are reported. In one dog, a syrinx was identified by ultrasonography. The only difference between dogs with or without syringomyelia was that dogs with Chiari-like malformation/syringomyelia were statistically older.

http://www3.interscience.wiley.com/j...elatedArticles

[Lisa_T]

I wonder how many of those were symptomatic?

And is it just me, or is 16 a tiny number to be studying - I question whether you would get anything but the most tentative of preliminary hypotheses from such a small sample.

[frecklesmom]

Well, I take it that they were all without symptoms-"normal". I think they were more into using this form of detection to see if it could be used large scale instead of the more costly MRI and they weren't into a large scale study. Even so, I guess what struck me is the numbers (%) still stay in the range of the prominent large studies. And then I wondered where the small numbers being tossed out in debates are coming from.

[Karlin]

The lowest figure of any formal researcher study was the North Carolina study -- which had 30% with SM. Almost all those cavaliers were asymptomatic and they were a mix of breeder and pet owner dogs (several breeders used the study as a good way to get MRIs done, if they were in the vicinity). All those cavaliers were under 5 which would tend to generate a lower level of affectedness for a progressive condition, as the dogs were all relatively young. Other studies with higher figures have had older dogs.

Rod has the two abstracts that summarise the work on cavalierhealth.org.

The 'disputed' figures of incidence come from two club health surveys -- so obviously only show what owners report with the vast majority of dogs unscanned. If I recall correctly, the majority of US owners didn't even answer the question about SM, presumably as they either didn't know what it was or hadn't scanned and thus wouldn't know whether their dog had it. In the US (ACKCSC) sample however 4% were MRI- confirmed with SM, and about 5% more were believed to have SM. So nearly 9%. In the UK Kennel Club survey, only 2% said their dogs had SM -- again self reporting. It seems surprising that US dogs have a far greater level of incidence even in self-reporting owners... which would tend to make one think self-reporting club breed surveys may not be too reliable and often is based on limites samples. Actually, there's a disclaimer along those lines on the front of the KC health survey!

Curiously the KC is insistent on the 2% figure though -- ignoring all the actual health studies and instead opting for the survey results. Even more curiously, they however totally downplay the fact that the survey showed over 37% of all pedigree dogs had at least one health problem -- instead they have massaged this figure into "90% of pedigree dogs are healthy" on the basis that several problems that most of us would consider rather debilitating for the dog, like eye problems, are not health threatening so therefore don't really qualify as "health issues". So the survey seems to be strictly interpreted when it suits the KC, and reinterpreted when it doesn't. It also seems odd that even as the KC is posting lists of studies it has supported or paid for -- to its credit -- it then in the case of cavaliers and SM, ONLY takes its figures from something as inexact as a breed survey (with many of the figures coming from breeders who might not wish to report scan results or may not have scanned), ignoring numerous studies across several continents. So is the KC saying that researcher's work doesn't matter, then, if it produces figures it doesn't like?

Even amongst the most skeptical cavalier people, though,I think one would be quite hard pressed to find many who truly believe that 2% figure. I think breeders are familiar enough with some of the scan results coming back to friends and acquaintances to know this would seem very unlikely.

[frecklesmom]

Thank you, Karlin. The low numbers being used then are self-reporting. So, no science involved only physical observation at best.

[Karlin]

I know all the researchers would greatly welcome the clubs or other sources funding a study of a large truly random sample of cavaliers to be scanned as that would give a sample unbiased either by people bringing them to be scanned and not saying they saw symptoms (though unless breeders and pet owners are lying, it is hard to dismiss figures from something like the North Carolina study, as the majority of dogs were said to be asymptomatic, and presumably assumed to be without syrinxes). And Geoff Skerritt has scanned around 1200 cavaliers, huge numbers of those asymptomatic dogs for breeders seeking information for breeding, and he is seeing significant figures for level of SM as well, as he has pointed out.

[frecklesmom]

1200 Cavaliers is one big group for a study and kudoes to the dedicated Docs. has there ever been an estimate how many Cavaliers there are in specific countries and what numbers are best to extrapolate data or is percent the best figure instead of numbers? If in the US we could get some low cost MRI clinics at multiple locations there would be a chance at getting good participation.