A proposed radiographic classification scheme for congenital thoracic vertebral malformations in brachycephalic “screw-tailed”dog breeds

Congenital vertebral malformations are common in brachycephalic “screw-tailed” dog breeds such as French bulldogs, English bulldogs, Boston terriers, and pugs. The aim of this retrospective study was to determine whether a radiographic classification scheme developed for use in humans would be feasible for use in these dog breeds. Inclusion criteria were hospital admission between September 2009 and April 2013, neurologic examination findings available, diagnostic quality lateral and ventro-dorsal digital radiographs of the thoracic vertebral column, and at least one congenital vertebral malformation. Radiographs were retrieved and interpreted by two observers who were unaware of neurologic status. Vertebral malformations were classified based on a classification scheme modified from a previous human study and a consensus of both observers. Twenty-eight dogs met inclusion criteria (12 with neurologic deficits, 16 with no neurologic deficits). Congenital vertebral malformations affected 85/362 (23.5 per cent) of thoracic vertebrae. Vertebral body formation defects were the most common (butterfly vertebrae 6.6 per cent, ventral wedge-shaped vertebrae 5.5 per cent, dorsal hemivertebrae 0.8 per cent, and dorso-lateral hemivertebrae 0.5 per cent). No lateral hemivertebrae or lateral wedge-shaped vertebrae were identified. The T7 vertebra was the most commonly affected (11/28 dogs), followed by T8 (8/28 dogs) and T12 (8/28 dogs). The number and type of vertebral malformations differed between groups (P = 0.01). Based on MRI, dorsal and dorso-lateral hemivertebrae were the cause of spinal cord compression in 5/12 (41.6 per cent) of dogs with neurologic deficits. Findings indicated that a modified human radiographic classification system of vertebral malformations is feasible for use in future studies of brachycephalic “screw-tailed” dogs. The study is from the College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.

Gutierrez-Quintana R, Guevar J, Stalin C, et al. Vet Radiol Ultrasound 2014 May 16 [Epub ahead of print].