Facial changes related to brachycephaly in Cavalier King Charles Spaniels with Chiari-like malformation associated pain and secondary syringomyelia.
J Vet Intern Med 2019;
34:237-246. [PMID:
31691386 PMCID:
PMC6979263 DOI:
10.1111/jvim.15632]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/23/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND
Recent studies including an innovative machine learning technique indicated Chiari-like malformation (CM) is influenced by brachycephalic features.
OBJECTIVES
Morphometric analysis of facial anatomy and dysmorphia in CM-associated pain (CM-P) and syringomyelia (SM) in the Cavalier King Charles Spaniel (CKCS).
ANIMALS
Sixty-six client-owned CKCS.
METHODS
Retrospective study of anonymized T2W sagittal magnetic resonance imaging of 3 clinical groups: (1) 11 without central canal dilation (ccd) or SM (CM-N), (2) 15 with CM-P with no SM or <2 mm ccd (CM-P), and (3) 40 with syrinx width ≥4 mm (SM-S). Morphometric analysis assessed rostral skull flattening and position of the hard and soft palate relative to the cranial base in each clinical group and compared CKCS with and without SM-S.
RESULTS
Sixteen of 28 measured variables were associated to SM-S compared to CM-N and CM-P. Of these 6 were common to both groups. Predictive variables determined by discriminant analysis were (1) the ratio of cranial height with cranial length (P < .001 between SM-S and CM-N) and (2) the distance between the cerebrum and the frontal bone (P < .001 between SM-S and CM-P). CM-P had the lowest mean height of the maxillary area.
CONCLUSIONS AND CLINICAL IMPORTANCE
CKCS with CM-P and SM-S have cranial brachycephaly with osseous insufficiency in the skull with rostral flattening and increased proximity of the hard and soft palate to the cranial base. Changes are greatest with CM-P. These findings have relevance for understanding disease pathogenesis and for selection of head conformation for breeding purposes.
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