Laurent Cauzinille, DMV, Ecole Nationale Veterinaire de Maisons Alfort, Paris, France
Neurology and Neurosurgery Department, Centre Hospitalier Fregis, Arcueil, France
“Incidence of caudal occipital malformation syndrome and ultrasound, computed tomographic, magnetic resonance imaging findings in 16 clinically normal Cavalier King Charles Spaniel genitors�
Authors: Jerome Couturier, Delphine Rault, Laurent Cauzinille
“We had two years ago, what we called ‘the French exception’. There was ‘no SM in France’,� Cauzinille said. The French CKCS club referred to SM as ‘the British CKC disease.’ Then, a couple of cases appeared and now there are more than 25 known cases.
In November 2004 he gave the first lecture and produced an article on SM in cavaliers. In June 2006, the French club accepted his proposed study, which was small but with two key French breeders, conducted at the the Vet Imaging Centre in Paris.
* 16 dogs in the study
* all were clinically and neurologically ‘normal’ according to their breeders (who filled in a questionnaire) and verified by neurologist’s tests (but not MRI)
*all were LOF (French kennel club pedigree) and breeding dogs
* Dr Couterier performed the neurological clinical testing, which included checking for: cervicalgia, hyperesthesia, scrathcing, ataxia, paresia, abnormal head posture, scoliosis, strabismus, facial paralysis, cranial nerve deficit
A number of study tests were then done.
*Ultrasound was performed on awake dogs with the goal of trying to find a less expensive screening test. Diameter of the spinal cord was measured at C1/C2 and at the level of the foramen magnum with the head flexed 90 degrees.
* Dogs were then anaesthetised, and a spiral CT scan was performed from the tuberculum sellae to the dens of the axis. Sagittal, transverse and dorsal images were taken (which is quite extensive). Linear measurements and area of the caudal fossa were obtained in the sagittal plane; height of the foramen magnum; area of the caudal fossa. In the transverse plane at the level of the widest part of the caudal fossa, linear measurement of the maximum width of the fossa was obtained.
*Then, dogs were MRId in a dorsal recumbent position using a 0.3T MR system -- the skull to the 1st thoracic vertebrae. If there, they measured hydrocephalus, ventricles, cerebellar size and degree of herniation.
As a result of these tests, the population was divided into groups: 1) normal; 2) syrinx; 3) hydrocephalus but no syrinx.
1) normal dogs: 8, 7 males and 1 female -- but had Chiari-like malformation
2) syrinx: 7 had SM, 3 males and 4 females, “a big shock to the breeders�
3) hydrocephalus but no syrinx: 1 male
In all the dogs, no statistically significant difference was found in the measurements taken except in the hydrocephalic dog. With this group, 43% of clinically normal champion breeding dogs (genitors) have SM “so there’s no more ‘French exception’.� But this is only 16 dogs so researcher cannot give a percentage affected for France, but these were were all pedigree dogs representing 6 key breed lines all with common ancestors.
Q&A:
* There was no association between the degree of herniation and SM. Doesn’t know if size of caudal fossa matters.
*They were able to pick up syrinxes with ultrasound
* They will repeat MRIs on the French dogs in 1 year and 3 years. He hopes King Charles Spaniels can be included in future research.
* The doctor doing the ultrasound was impressed with how much of the cerebellum could be seen with ultrasound.
* He thinks the next step is to keep looking at CSF dynamics -- “the thing that will really help us to progress a lot.