Prevalence of lumbosacral transitional vertebrae in dogs in the Czech Republic

Lumbosacral transitional vertebra is a common congenital anomaly of the spine in dogs. It is a predisposing factor for degeneration of the lumbosacral spine and development of cauda equina syndrome or hip dysplasia in affected dogs. The aim of the study was to determine breed predisposition, types, and prevalence of lumbosacral transitional vertebrae in the canine population in the Czech Republic. The value of laterolateral radiographs of the lumbosacral junction in the diagnosis of LTV was also evaluated. Prevalence of lumbosacral transitional vertebrae was determined by reviewing ventrodorsal radiographs of pelvis with an extended hip of 1,878 dogs. Lumbosacral transitional vertebrae were detected in 188 dogs (10%). German Shepherd, Alaskan Malamute and Bohemian Shepherd were found to be highly predisposed breeds. The most common type of lumbosacral transitional vertebra was type II with separation of the first sacral vertebra from sacrum and presence of rudimentary intervertebral space between S1 and the sacral median crest (37.8% of the lumbosacral transitional vertebrae). Type I was detected in 29.2% and the asymmetric type of the lumbosacral transitional vertebra (type III) in 33%. Laterolateral radiograph of the lumbosacral spine was evaluated in 126 dogs from 188 with lumbosacral transitional vertebrae. Rudimentary intervertebral disc space between S1 and S2 in laterolateral radiographs was detected in 100% of lumbosacral transitional vertebrae with type II and III, and was not detected in type I. The findings on lumbosacral transitional vertebrae in the Czech Republic will extend knowledge about the disease. Both ventrodorsal hip-extended and laterolateral radiographs should be recommended for routine screening and reliable differentiation among the three different types of lumbosacral transitional vertebra. Hip dysplasia, cauda equina syndrome, radiography Lumbosacral transitional vertebra (LTV) is a congenital abnormally formed vertebra between the last normal lumbar vertebra and the first normal sacral vertebra (Morgan 1968; Damur-Djuric et al. 2006). The LTV has the characteristics of both spinal segments, although definition varies in veterinary literature (Morgan 1968; Col ter 1993; Morgan 1999; Damur-Djuric et al. 2006; Westworth and Sturges 2010). It is assumed that the LTV is a predisposing factor for earlier degeneration of lumbosacral junction and it is a risk factor for development of cauda equina syndrome (Lang et al. 1992; Morgan et al. 1993; Flückiger et al. 2006; Moore et al. 2001). The asymmetric type of LTV may result in pelvis rotation with a unilateral increase load of the hip and a higher degree of hip dysplasia (Flückiger et al. 2009). It is assumed that the occurrence of LTV has a hereditary condition, although the type of inheritance of LTV has not been elucidated yet (Flückiger et al. 2009). Prevalence of LTV in populations of dogs in different countries varies from 2.5 to 40.4% in dependence on the classification system (Morgan 1999; Damur-Djuric et al. 2006; Ledecký et al. 2007; Wigger 2009; Lappalainen et al. 2012). To the authors’ knowledge, no work has been published relating specifically to prevalence of LTV in pure breed dogs in the Czech Republic. The aim of this study was to determine the prevalence of lumbosacral transitional vertebrae in the dog population in ACTA VET. BRNO 2014, 83: 399–403; doi:10.2754/avb201483040399 Address for correspondence: MVDr. Iva Fialová Small Animal Clinic University of Veterinary and Pharmaceutical Sciences Brno Palackého tř. 1/3, 612 42 Brno, Czech Republic Phone: +420 604 766 660 E-mail: [email protected] http://actavet.vfu.cz/ the Czech Republic, and the value of laterolateral radiographs of lumbosacral junction in determination of LTV type. Materials and Methods Radiographs of dogs that were screened for hip dysplasia or other problems with pelvis or the hip joint were evaluated at the University of Veterinary and Pharmaceutical Sciences Brno in the years 2007–2013. Radiographs of 1,878 dogs (892 males and 986 females), were evaluated retrospectively for presence of LTV. Their age ranged from 7 months to 11 years (median 1.6 years). For each dog, a ventrodorsal radiograph was taken of the pelvis with the pelvic limbs extended. Additionally, in some dogs laterolateral radiographs of lumbosacral spine were available. Two of the authors evaluated the radiographs together and assessed the morphology of the lumbosacral spine. The occurrence and type of LTV and the breed were classified by consensus of the evaluators. One of them is certified reviewer. Prevalence of LTV was evaluated individually in 24 breeds with a minimum of 15 dogs per breed. Breeds with less than 15 dogs per breed were classified as “other breeds”. We used LTV evaluation according to Flückiger et al. (2009) as a basic classification scheme: type 0 is a normally shaped section of the lumbosacral spine. Type I of LTV in dogs is separated spinous process of the first sacral vertebra (S1) from the medial crest without signs of rudimental intervertebral space between S1and the rest of the sacrum. The LTV II is completely separated from sacrum; transverse processes are symmetrical and can be in a different attachment to the pelvis. Type III is an asymmetric type of LTV; transverse processes have different shapes (Flückiger et al. 2009). The LL radiograph of the lumbosacral spine was evaluated for presence of intervertebral space between the first and second sacral vertebrae. Presence of intervertebral space was evaluated subjectively as the presence of radiolucent line representing the intervertebral disc. A χ2-test was used for statistical analysis of LTV in relation to sex.