Computer-Assisted Radiographic Calculation of Spinal Curvature in Brachycephalic “Screw-Tailed” Dog Breeds with Congenital Thoracic Vertebral Malformations: Reliability and Clinical Evaluation

Abstract

The objectives of this study were: To investigate computer-assisted digital radiographic measurement of Cobb angles in dogs with congenital thoracic vertebral malformations, to determine its intra- and inter-observer reliability and its association with the presence of neurological deficits. Medical records were reviewed (2009–2013) to identify brachycephalic screw-tailed dog breeds with radiographic studies of the thoracic vertebral column and with at least one vertebral malformation present. Twenty-eight dogs were included in the study. The end vertebrae were defined as the cranial end plate of the vertebra cranial to the malformed vertebra and the caudal end plate of the vertebra caudal to the malformed vertebra. Three observers performed the measurements twice. Intraclass correlation coefficients were used to calculate the intra- and inter-observer reliabilities. The intraclass correlation coefficient was excellent for all intra- and inter-observer measurements using this method. There was a significant difference in the kyphotic Cobb angle between dogs with and without associated neurological deficits. The majority of dogs with neurological deficits had a kyphotic Cobb angle higher than 35°. No significant difference in the scoliotic Cobb angle was observed. We concluded that the computer assisted digital radiographic measurement of the Cobb angle for kyphosis and scoliosis is a valid, reproducible and reliable method to quantify the degree of spinal curvature in brachycephalic screw-tailed dog breeds with congenital thoracic vertebral malformations.

Ventral stabilization of thoracic kyphosis through bilateral intercostal thoracotomies using SOP (String of Pearls) plates contoured after a 3‐dimensional print of the spine

“…When they are combined, these abnormalities cause repetitive, dynamic damage of the spinal cord . This condition is most prevalent in small dogs, specifically, corkscrew tailed dogs (pug, English bulldog, French bulldog, Boston terrier) . Malformed vertebrae are often incidental findings, particularly in French bulldogs.…”

“…In pugs however, hemivertebrae are more commonly associated with secondary neurological deficits . The mid‐thoracic vertebrae (T6‐T9) are most commonly affected . Clinical signs are related to the neuroanatomical localization of the disease, often consisting of a chronic, progressive T3‐L3 myelopathy with varying degrees of proprioceptive paraparesis and pelvic limb ataxia.…”

“…[1][2][3] This condition is most prevalent in small dogs, specifically, corkscrew tailed dogs (pug, English bulldog, French bulldog, Boston terrier). [1][2][3][4][5][6] Malformed vertebrae are often incidental findings, particularly in French bulldogs. In pugs however, hemivertebrae are more commonly associated with secondary neurological deficits.…”

“…6 The mid-thoracic vertebrae (T6-T9) are most commonly affected. 2,[4][5][6] Clinical signs are related to the neuroanatomical localization of the disease, often consisting of a chronic, progressive T3-L3 myelopathy with varying degrees of proprioceptive paraparesis and pelvic limb ataxia. Deterioration may be acute or chronic, leading to nonambulatory paraparesis or paraplegia and urinary retention.…”

Late‐onset wedge‐shaped thoracic vertebrae in a six‐month‐old pug

“…(Aikawa and others 2007). A kyphotic angle of more than 35° has a positive predictive value of 75 per cent for related neurological deficits (Moissonnier and others 2011, Guevar and others 2014). Lameness of the hind limbs as a result of spinal cord compression was present in this case.…”