Contributions to the Study of Transitional Vertebrae in Dogs
World Small Animal Veterinary Association World Congress Proceedings, 2009
F.C. Cavaletti; S.L.R. Urtado; M.H. Vac
Institute Veterinary of Image, Vila Madalena, São Paulo, SP, Brazil


Transitional vertebrae are a congenital anomaly characterized by abnormal development of the vertebral body, with anatomical characteristics of the region adjacent (Owens & Biery 1998). It can be found with radiographic finding or foster instability and degeneration of the vertebral body. Affects dogs of various breeds, large or small size, and both gender, however, German Shepherd, Lhasa apso and Shih-tzu has a high frequency (Thrall 2002).

Materials and Methods

All animals were radiographed in the Institute Veterinary of Image with a Techno-design analog, 500mA, high frequency, floating table, Porterbucky Techno-design and chassis and film Kodak with proportional sizes to the dogs. The protocol of the institute for study of the column is to radiography projections laterolateral, and if there is a need to supplement with the projection ventro-dorsal, however the regions are requested by colleagues who send their patients for the exam. We conducted a survey of the radiographic reports of 430 dogs with transitional vertebrae, aiming to contribute to the study of the disease and show the most affected regions and prone to develop a degenerative process.


We noticed that most of the transitional vertebrae is in the lumbosacral region and thoracolumbar with 65.5% (282 animals) and 28.1% (121 animals). In 70.9% (200 animals) cases of transitional vertebrae in the lumbosacral region show signs of instability and degeneration associated and, 47.1% (57 animals) thoracolumbar region. Sacralization of L7 was the most frequent that lumbarization of S1 with 68.4% (193 animals) and 31.5% (89 animals) respectively. In thoracolumbar region it did not reveal significant difference between the lumbarization of T13 and L1 thoracolization with 53.7% (65 animals) and 46.2% (56 animals). The region sacrococcygeal also showed high incidence, with 20.7% (89 animals); in 42.6% (38 animals) of these cases, it had a transitional vertebrae in another region of the spine. The cervicothoracic region did not present importance radiographic with only 15 cases. In 17.9% (77 animals) they were found over a region affected by the transitional vertebrae and 15% (65) of the dogs had scoliosis, kyphosis or lordosis. In sacralization of L7, the fusion of left transverse process (55.4%) occurs more frequently than the right (38.3%) and in a few cases the merger was bilateral (6.2%). In lumbarization of T13, the bilateral aplasia of the ribs are more frequent (57.3%), followed by aplasia left (26.4%) and right (16.1%).

Discussion and Conclusions

The lumbosacral and thoracolumbar region were represented in higher radiographic and clinical importance, and show a high incidence, degenerative signs frequent and often associated with intervertebral disc disease or caudal equina syndrome (Flãckiger et al. 2006). In the lumbosacral region, the sacralization of L7 is more frequent than lumbarization. Most animals with transitional vertebrae sacrococcygeal show other regions affected by the disease, though the merger between Cco1 with S3 is seen only as a radiographic finding. The cervicothoracic region showed no significant importance (Thrall 2002). Difficulty in diagnostics may occur when more than one region is affected by the transitional vertebrae, impossible to count the vertebrae without X-ray the entire length of the spine. We know the transitional vertebrae favors of the instability of the vertebral body, but in the lumbosacral we noticed that this process occurred with greater frequency and severity. Another important factor we should consider is the influence of the transitional vertebrae lumbosacral and sacroiliac morphology with the development of hip dysplasia which can encourage the process of osteoarthritis (Damur-Djuric et al. 2006).


1.  Owens JM, Biery DN. 1998. Radiographic Interpretation for the Small Animal Clinician, 2:133-134, Willians and Wilkins.

2.  Thrall DE. 2002. Textbook of Veterinary Diagnostic Radiology, 4:99-100, Saunders.

3.  Flãckiger MA, Damur-Djuric N, Hãssig M, Morgan JP, Steffen F. 2006. A lumbosacral transitional vertebra in the dog predisposes to cauda equina syndrome. Veterinary radiology & ultrasound, 47: 39-44.

4.  Damur-Djuric N, Steffen F, Hãssig M, Morgan JP, Flãckiger MA. 2006. Lumbosacral transitional vertebrae in dogs: classification, prevalence, and association with sacroiliac morphology. Veterinary radiology & ultrasound, 47:32-8.


Speaker Information
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F. C. Cavaletti
Institute Veterinary of Image
São Paulo, SP, Brazil

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