5th April 2009, 09:08 PM
Caudal Fossa Volume in Cavaliers and Other Breeds
I found a new CM/SM research article, just published this month. It included 40 Cavaliers, all with CM (that was intended) and 14 of them also with SM. It focused on the "volumes of cranial cavities in Cavalier King Charles Spaniels with Chiari-like malformation" and compared them to volumes of cranial cavities in "other brachycephalic" dogs.
The conclusion: "Results of this study suggested that descent of the cerebellum into the foramen magnum and the presence of syringohydromyelia in CKCSs are not necessarily associated with a volume reduction in the [caudal fossa] of the skull."
The abstract of this article is pasted at the end of this post. This conclusion may differ from an article published last month, with concluded: "CKCSs had a shallower caudal cranial fossa and abnormalities of the occipital bone, compared with those of mesaticephalic dogs. These changes were more severe in CKCSs with syringomyelia." That article obviously compared the Cavalier with mesaticephalic dogs, rather than brachycephalic dogs.
Here is the abstract of the April article:
Evaluation of the volumes of cranial cavities in Cavalier King Charles Spaniels with Chiari-like malformation and other brachycephalic dogs as measured via computed tomography. Schmidt MJ, Biel M, Klumpp S, Schneider M, Kramer M. Am J Vet Res. 2009 Apr;70(4):508-12. Quote: "Objective-To measure the absolute and relative volumes of cranial vaults of Cavalier King Charles Spaniels (CKCSs) and other brachycephalic dogs for the purpose of evaluating a possible association between the volume of the caudal fossa (fossa caudalis cerebri; CF) and existence of Chiari-like malformation (CLM) and syringohydromyelia in CKCSs. Animals-40 CKCSs and 25 brachycephalic dogs. Procedures-The intracranial vault of all dogs was evaluated via computed tomography followed by magnetic resonance imaging. Volumes of the CF and the rostral and medial fossa (fossa rostralis et medialis cerebri) were determined. The ratio of the absolute volumes was calculated as the volume index (VI). Results-All CKCSs had cranial characteristics consistent with CLM. There were no significant differences between CKCSs and brachycephalic dogs with respect to the VI and absolute volumes of the CF and rostral and medial fossas. The CKCSs without syringohydromyelia (n = 26) had a median VI of 0.1842, and CKCSs with syringohydromyelia (14) had a median VI of 0.1805. The median VI of other brachycephalic dogs was 0.1864. The VI did not differ among these 3 groups. Conclusions and Clinical Relevance-Results of this study suggested that descent of the cerebellum into the foramen magnum and the presence of syringohydromyelia in CKCSs are not necessarily associated with a volume reduction in the CF of the skull."