Autor: Svenja Kristiane Florczak

Assimilation Disorders of the Vertebral Column at the Lumbosacral Transition in the Rhodesian Ridgeback, Basset Hound and Hovawart and the Prevalence of Other Skeletal Developmental Disorders (HD, ED, OCD) In the present study, the prevalence of lumbosacral transitional vertebrae (LTV) in three dog breeds (Rhodesian Ridgeback, Basset Hound and Hovawart) and a possible disposition of these breeds for hip dysplasia were examined by means of radiography in ventrodorsal projection. The radiographs were obtained from HD (hip dysplasia) screening examinations and were retrospectively evaluated in relation to LTV. The HD findings were recorded from the case report forms. HD was diagnosed according to the guidelines of the FCI (Federation Cynologique International). For the breed Rhodesian Ridgeback, additionally, the findings concerning elbow joint dysplasia (ED) and osteochondrosis dissecans (OCD) of the humeral head according to the IEWG (International Elbow Working Group) guidelines were taken from the finding sheets and correlated with LTV for the first time in this study. In total, HD X-rays of N=2402 Rhodesian Ridgebacks, N=249 Basset Hounds and N=116 Hovawarts were available. For N=1815 of the Rhodesian Ridgebacks, radiographs of the elbow joints in the basic image pair (craniocaudal and mediolateral) and N=1788 of the shoulder joints in the medio-lateral projection were available. A total of 154 radiographs were not considered in the context of this evaluation, due to inadequate patient positioning and/or X-ray technique, overlays of the area of interest with faeces or similar disqualifiers in other locations. 427 radiographs went missing, because they had to be sent to the supervising reviewer, but were not returned. LTV were detected in 6.7% (159/2377) of the dogs in the study population. Rhodesian Ridgebacks were affected in 7.4% (140/2012), Basset Hounds in 2.8% (7/249) and Hovawarts in 2.6% (3/116) of cases. Symmetric LTV were detected in 4.6% (n=109) of the dogs, of which 5.0% (101/2012) were Rhodesian Ridgebacks, 2.0% (5/249) Basset Hounds and 2.6 % (3/116) Hovawarts. The prevalence of asymmetric LTV in this study was 2.1% (50/2012), of which 2.4% (48/2012) where found in Rhodesian Ridgebacks, 0.8% (2/249) in Basset Hounds and none in Hovawarts. A sex disposition could not be proven for any of the breeds. The LTV findings were correlated with those with HD. For LTV and HD, in general, there was no significant correlation, neither for the entire study population, nor for the individual breeds. For the Rhodesian Ridgeback, the correlation between LTV (149/2012) and higher HD-grades (non-eligible for breeding = HD-grade C, D and E) was statistically significant (p<0,05), likewise for the asymmetric LTV (48/2012) and the HD-grades C, D and E (p <0.05). There were no significant correlations for other morphological abnormalities in the lumbosacral area, such as a differing number of sacral vertebrae (28/1833) or an altered intervertebral space L7/S1 (141/1825) in the entire study population or in the individual breeds. The correlation of LTV with disorders from the elbow joint dysplasia complex (ED) and osteochondritis dissecans (OCD) of the humeral head in Rhodesian Ridgebacks were statistically significant (ED 26/1815, FPC 23/1826): for LTV and ED (p <0.01) and its degrees of severity (p <0,05) and LTV and fragmented processus coronoideus (FPC) (p <0.05) and its degrees of severity (p <0.05). The correlations were not significant for OCD of the elbow joint, the isolated processus anconaeus ulnae (IPA), likewise for OCD of the shoulder joint. An intracondylar OCD / incomplete ossification of the humeral condyle (IOHC) did not occur in the study population. HD also correlated significantly with ED (p <0.001) and its degrees of severity (p <0.001), likewise with FPC (p <0.001) and its degrees of severity (p <0.001). In addition, the correlation between HD and osteochondritis dissecans (OCD) of the elbow joint was significant (p <0.05). The correlations were not statistically significant for the other diseases. In summary, the results of this study support the literature references that demonstrated positive correlations between LTV and HD. In this study, however, the relationships were only significant for the severe HD forms, as KOMSTA et al. (2015) showed. The significant correlations between HD and ED observed in previous studies could also be confirmed with this work. The correlations of LTV and ED, and OCD, which were also statistically significant, were investigated for the first time in this study.