Changes over time in craniocerebral morphology and syringomyelia in cavalier King Charles spaniels with Chiari-like malformation

Abstract

BackgroundChiari-like malformation (CM) and syringomyelia is a neurological disease complex with high prevalence in cavalier King Charles spaniels (CKCS). The natural progression of this disease with time has not been described. The objectives of this study were to i) determine if syringomyelia progresses with time ii) determine if features of craniocrebral morphology previously associated with CM are progressive (including caudal cranial fossa volume, caudal cranial fossa parenchymal volume, ventricular dimensions, height of the foramen magnum and degree of cerebellar herniation). A retrospective morphometric analysis was undertaken in 12 CKCS with CM for which repeat magnetic resonance images were available without surgical intervention.ResultsThe maximal syrinx width, height of the foramen magnum, length of cerebellar herniation and caudal cranial fossa volume increased over time. Ventricular and caudal fossa parenchymal volumes were not significantly different between scans.ConclusionsThe results of this study suggest that syringomyelia progresses with time. Increased caudal cranial fossa volume may be associated with active resorption of the supraoccipital bone, which has previously been found in histology specimens from adult CKCS. We hypothesise that active resorption of the supraoccipital bone occurs due to pressure from the cerebellum. These findings have important implications for our understanding of the pathogenesis and variable natural clinical progression of CM and syringomyelia in CKCS.

Longitudinal Study of the Relationship among Craniocervical Morphology, Clinical Progression, and Syringomyelia in a Cohort of Cavalier King Charles Spaniels

“…Thus, in our cohort, approximately two‐thirds of asymptomatic dogs remained asymptomatic throughout the study period, despite the majority (>80%) having shown CCJ morphologic abnormalities on initial imaging. Previous studies in CKCS have shown a similar absence of correlation between clinical status at the time of imaging and the presence and severity of cerebellar herniation (presence and length), , cerebellar indentation, and foramen magnum height . One study, in fact, recently suggested that cerebellar indentation and impaction (ie, triangulation) should be considered a “normal” anatomic variation inherent to the CKCS breed, because of its high prevalence in asymptomatic CKCS.…”

Cerebellar and hindbrain motion in Chiari malformation with and without syringomyelia

“…Interestingly, the average tonsillar motion (CLM/CM-I with syrinx values given) was much greater and more variable in dogs (4.18 ± 2.63 mm according to Driver et al 16 ) than that in humans (current study 0.81 ± 0.47 mm; Bunck et al 5 1.0 ± 0.6 mm; Cousins and Haughton 11 0.61 ± 0.03 mm) despite similar or smaller degrees of herniation. 12,14,31 Whether increased cerebellar motion has a different effect on the canine system is unknown. Morphometric studies further suggest a probable difference between human and canine conditions.…”

Low‐Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs

“…However, any dilatation of the central canal should be considered abnormal. Hence, the detection of smaller dilatations on both MR and CT is important as progressive central canal dilatation is a precursor of syrinx formation 1, 34. Furthermore, results of a previous study suggest that SW progresses with time in CKCS 34.…”