Lumbosacral Transitional Vertebrae, Canine Hip Dysplasia, and Sacroiliac Joint Degenerative Changes on Ventrodorsal Radiographs of the Pelvis in Police Working German Shepherd Dogs

Lumbosacral transitional vertebra in 14 dog breeds in Norway: Occurrence, risk factors and association with hip dysplasia

A lumbosacral transitional vertebra (LTV) is a congenital anomaly of the spine and has been suggested to predispose to canine hip dysplasia (CHD). This retrospective, cross-sectional study investigated the prevalence of LTV and CHD among 14 dog breeds in Norway, the possible associations with risk factors, and whether LTV was a risk factor for the development of hip dysplasia. The results were based on evaluation of ventrodorsal radiographs from the CHD screening program from the Norwegian Kennel Club from February 2014 to January 2022. A total of 13,950 dogs were included in the study. For statistical analysis, CHD grades were reclassified from the official Federation Cynologique Internationale (FCI) grades into three grades: CHD free (CHD=A, B), CHD mild (CHD=C), and CHD severe (CHD=D, E). In the study sample, the overall occurrence of LTV was 18.5%, of which 32.9% were type 1, 45.7% type 2% and 21.4% type 3. The occurrence of LTV varied significantly among the included breeds, ranging from 9.5% to 46.2%. There was no association between sex and LTV. The frequencies of CHD grades were A: 43.1%; B: 31.4%; C: 18.4%; D: 6.0%; E: 1.1%. There was a statistically significant association with mild and severe CHD in dogs with LTV type 2 and LTV type 3 (P< 0.001). In the population studied, the prevalence of LTV was different among breeds. This supports initial data on the heredity of LTV and the diverse occurrence of LTV among breeds. Our results indicate that LTV type 2 and type 3 are associated with mild and severe CHD development. Therefore, this study has potentially identified an additional risk factor for the development of hip dysplasia.

Outcomes for 15 cats with bilateral sacroiliac luxation treated with transiliosacral toggle suture repair

OBJECTIVE

To report a surgical technique and outcomes of transiliosacral toggle suture repair to treat feline bilateral sacroiliac luxation/fracture (SILF).

STUDY DESIGN

Retrospective study.

ANIMALS

Fifteen client-owned cats.

METHODS

The medical records of cats with bilateral SILF treated using a transiliosacral toggle suture repair were reviewed. Short- and medium-term outcomes were assessed through standard postoperative clinical evaluation and radiographs, including measurements of angle of deviation (AoD), percentage of reduction (PoR), and pelvic canal width ratio (PCWR). Long-term functional follow up was obtained from a questionnaire derived from the Feline Musculoskeletal Pain Index (FMPI).

RESULTS

Fifteen cats were enrolled retrospectively, among which 13 survived to discharge. One minor wound complication, treated by secondary intention healing, was encountered. No major complication was reported. Immediately postoperatively, the mean absolute PoR values were 88.1 ± 11.2% and 91 ± 11.6% on the right and left side, respectively. The mean absolute AoD was 3.1 ± 2.8°, and the mean PCWR was 1.24 ± 0.08. The medium-term radiographic follow up at a median of 205 (71-682) days postsurgery revealed the good stability of the repair. Excellent functional outcomes were identified upon the analysis of 12 long-term questionnaires at a median of 365 (119-798) days postsurgery.

CONCLUSION

Anatomic reduction was satisfactory and comparable with previously described techniques with good implant placement documented. Functional outcomes based on FMPI-derived questionnaires were good to excellent in our population.

CLINICAL SIGNIFICANCE

Transiliosacral toggle suture stabilization of bilateral SILF was associated with good outcomes in cats. Further studies are required to compare biomechanical properties and outcomes between this technique and previously described transiliosacral stabilization.

The prevalence of sacroiliac joint CT and MRI findings is high in large breed dogs

Sacroiliac joint (SIJ) disease has been described as one of the possible causes of lumbosacral (LS) region pain in dogs. However, published information is currently lacking for the computed tomographic (CT) and magnetic resonance imaging (MRI) characteristics of canine SIJ disease. The objectives of this retrospective, observational study were to describe and quantify CT and MRI SIJ findings in a sample of large breed dogs and test associations between the numbers of SIJ findings and other variables. Data archives for a veterinary teaching hospital were searched for large breed dogs (≥ 22.7 kg) that had CT or MRI scans of the LS and pelvic regions in 2015-2019. Dogs with a history of acute trauma or scans with incomplete SIJs were excluded. A veterinary student recorded medical record findings. A veterinary radiologist and graduate student recorded CT and MRI findings based on previously published criteria in dogs and humans. Fifty-three dogs were sampled (20 CT, 33 MRI). Categories of findings with the highest prevalence were subchondral erosion (100% CT, 100% MRI) and subchondral sclerosis (95% CT, 97% MRI). The total numbers of SIJ findings per dog were not associated with dog age, sex, weight, or concurrent findings in the LS or pelvic regions. The total number of MRI SIJ findings per dog differed between German Shepherds and Labrador Retrievers (P = 0.0237) as well as between Labrador Retrievers and other breeds (P = 0.0414). These results indicated that CT and MRI findings reported in humans with SIJ disease are common in large breed dogs.

Canine Mobility Maintenance and Promotion of a Healthy Lifestyle

This article highlights the recommendations and considerations for maintaining a healthy canine lifestyle. A key component of a healthy lifestyle is the enhancement and optimization of mobility. Mobility is essential in maintaining a high quality of life and involves the interplay of a dog's structure, posture, body condition score, physical exercise, and a healthy human-animal bond throughout a dog's lifetime.

The Prevalence of Feline Hip Dysplasia, Patellar Luxation and Lumbosacral Transitional Vertebrae in Pedigree Cats in The Czech Republic

Simple Summary

Hip dysplasia, patellar luxation and lumbosacral transitional vertebra are not well described in cats, most likely because cats can often much better compensate for pelvic limb lameness and hide their pain and, as a result, owners are less likely to notice this condition. Pedigree cats at least 10 months old were recruited prospectively in this study to find the prevalence of feline hip dysplasia, patellar luxation and lumbosacral transitional vertebra. The prevalence of hip joint dysplasia in all pedigree cats was 46.7%, of which 78% of cats had bilateral dysplasia. Dysplasia was mainly from mild (grade 1) to moderate (grade 2); however, 6.1% of hip joints showed signs of severe hip dysplasia (grade 3) in Maine Coon and Siberian cats. Patellar luxation was noted in 32.7% of the pedigree cats, was present bilaterally in 91.4% and was grade 1 or 2 in most cats. The presence of lumbosacral transitional vertebra was noted in 7.5% of the pedigree cats. The high prevalence of hip dysplasia in pedigree cats should be considered and screening pedigree cats for hip dysplasia is recommended before they are used in breeding programs.

Abstract

(1) Background: The aim of this study was to find the prevalence of feline hip dysplasia (HD), patellar luxation and lumbosacral transitional vertebra (LTV) in pedigree cats in the Czech Republic. (2) Methods: 107 pedigree cats at least 10 months old were recruited prospectively at the Small Animal Clinic at the University of Veterinary and Pharmaceutical Sciences Brno, CZ, between April 2019 and July 2020. (3) Results: The prevalence of hip joint dysplasia in all pedigree cats was 46.7%, of which 78% of cats had bilateral dysplasia. The HD was mainly from mild (grade 1) to moderate (grade 2); however, 6.1% of hip joints showed signs of severe HD (grade 3) in Maine Coon and Siberian cats. Patellar luxation was noted in 32.7% of the pedigree cats, was present bilaterally in 91.4% and was grade 1 or 2 in most cats. The presence of LTV was noted in 7.5% of pedigree cats. (4) Conclusions: The high prevalence of HD in pedigree cats should be considered and screening pedigree cats for HD is recommended before they are used in breeding programs.

Genetic background of lumbosacral transitional vertebrae in German shepherd dogs

OBJECTIVES

Estimation of genetic parameters of lumbosacral transitional vertebrae based on data derived from radiographic screening of 27,597 German shepherd dogs.

MATERIALS AND METHODS

Results of radiographic screening for lumbosacral transitional vertebrae classified according to a published scheme were collected. Obtained data were used for estimating variance components in single and multiple trait linear animal models to obtain heritabilities and additive genetic correlations for different types of lumbosacral transitional vertebrae.

RESULTS

Estimations indicated a moderate heritability of lumbosacral transitional vertebrae of h²  = 0.27. Trait definitions reflecting the different types of lumbosacral transitional vertebrae revealed positive additive genetic correlations of r_g  > 0.5 between those types usually categorised as pathologic.

CLINICAL SIGNIFICANCE

Results of comprehensive genetic analyses enable the development of breeding measures against lumbosacral transitional vertebrae to reduce their prevalence and support management of potentially correlated diseases in German shepherd dogs.

CT and gross pathology are comparable methods for detecting some degenerative sacroiliac joint lesions in dogs

Degenerative sacroiliac joint disease is a cause of lumbosacral pain in dogs; however, published information on cross-sectional imaging characteristics is limited. Objectives of this retrospective, secondary analysis, methods-comparison study were to test hypotheses that CT lesions reported in humans with degenerative sacroiliac joint disease are also present in dogs, and that CT is comparable to gross pathology for detecting these lesions. Matched CT and gross pathology slice images of 30 sacroiliac joints were retrieved from a previous prospective, canine cadaver study. A veterinary radiologist interpreted randomized CT images for each joint based on previously published CT characteristics of lesions in humans with degenerative sacroiliac joint disease. A veterinary pathologist independently interpreted randomized gross pathology images using the same criteria. All joints had at least one CT lesion consistent with degenerative sacroiliac joint disease. A new CT lesion was also identified and termed "subarticular cleft." The CT and gross pathology methods agreed for detecting joints with subchondral sclerosis, subchondral erosion, and intra-articular ankylosis lesions (P > .05, McNemar's test), but disagreed for detection of joints with subchondral cyst, para-articular ankylosis, and subarticular cleft lesions (P ≤ .05). Using gross pathology as the reference standard, CT had 100% sensitivity for detection of subarticular cleft and subchondral cyst lesions, with 56% and 22% specificity, respectively. Para-articular ankylosis lesions were detected by CT but not by gross pathology. Findings supported the hypothesis that CT lesions reported in humans with degenerative sacroiliac joint disease are also present in dogs, and partially supported the hypothesis that CT is comparable to gross pathology for detecting joints with these lesions.

Lumbosacral transitional vertebrae in cats and its relationship to lumbosacral vertebral canal stenosis

OBJECTIVES

Although a clear relationship has been demonstrated between the presence of lumbosacral transitional vertebrae and the development of lumbosacral stenosis in dogs, this relationship has not been evaluated in cats. The aim of this study was to investigate the relationship between the presence of lumbosacral transitional vertebrae and lumbosacral stenosis in cats.

METHODS

The medical records and diagnostic imaging studies of 13 cats diagnosed with lumbosacral stenosis were retrospectively reviewed for lumbosacral abnormalities and compared with findings of 405 cats that underwent CT for reasons unrelated to spinal disease.

RESULTS

Clinical signs associated with lumbosacral stenosis included lumbosacral pain, low tail carriage, difficulty jumping, and urinary or faecal incontinence. Neurological signs included proprioceptive deficits, ambulatory paraparesis, pelvic limb ataxia, reduced spinal reflexes and reduced perianal reflex. Duration of clinical signs ranged from 1 day to 10 months (mean 3 months). Of the 13 cats with lumbosacral stenosis, seven (53.8%) were diagnosed with lumbosacral transitional vertebrae. In the control population of 405 cats, 24 (5.9%) were diagnosed with lumbosacral transitional vertebrae. Results indicated that lumbosacral transitional vertebrae were significantly ( P <0.0001) more prevalent in cats with lumbosacral stenosis compared with the control feline population (odds ratio 18.52, 95% confidence interval 6.1-62.1). Development of clinical signs of lumbosacral stenosis in cats with lumbosacral transitional vertebrae (mean 10.8 years) was not significantly different from that of cats without lumbosacral transitional vertebrae (mean 12.7 years). Likewise, there was no significant influence of breed ( P >0.99) or sex ( P = 0.29) on the occurrence of lumbosacral transitional vertebrae.

CONCLUSIONS AND RELEVANCE

Despite lumbosacral stenosis being a rare spinal condition in cats, lumbosacral transitional vertebrae can be considered a risk factor for its development.

C7 vertebra homeotic transformation in domestic dogs - are Pug dogs breaking mammalian evolutionary constraints?

The number of cervical vertebrae in mammals is almost constant at seven, regardless of their neck length, implying that there is selection against variation in this number. Homebox (Hox) genes are involved in this evolutionary mammalian conservation, and homeotic transformation of cervical into thoracic vertebrae (cervical ribs) is a common phenotypic abnormality when Hox gene expression is altered. This relatively benign phenotypic change can be associated with fatal traits in humans. Mutations in genes upstream of Hox, inbreeding and stressors during organogenesis can also cause cervical ribs. The aim of this study was to describe the prevalence of cervical ribs in a large group of domestic dogs of different breeds, and explore a possible relation with other congenital vertebral malformations (CVMs) in the breed with the highest prevalence of cervical ribs. By phenotyping we hoped to give clues as to the underlying genetic causes. Twenty computed tomography studies from at least two breeds belonging to each of the nine groups recognized by the Federation Cynologique Internationale, including all the brachycephalic 'screw-tailed' breeds that are known to be overrepresented for CVMs, were reviewed. The Pug dog was more affected by cervical ribs than any other breed (46%; P < 0.001), and was selected for further analysis. No association was found between the presence of cervical ribs and vertebral body formation defect, bifid spinous process, caudal articular process hypoplasia/aplasia and an abnormal sacrum, which may infer they have a different aetiopathogenesis. However, Pug dogs with cervical ribs were more likely to have a transitional thoraco-lumbar vertebra (P = 0.041) and a pre-sacral vertebral count of 26 (P < 0.001). Higher C7/T1 dorsal spinous processes ratios were associated with the presence of cervical ribs (P < 0.001), supporting this is a true homeotic transformation. Relaxation of the stabilizing selection has likely occurred, and the Pug dog appears to be a good naturally occurring model to further investigate the aetiology of cervical ribs, other congenital vertebral anomalies and numerical alterations.

Asymmetrical lumbosacral transitional vertebrae in dogs may promote asymmetrical hip joint development

Objectives: This study examines the relationship between the morphology of the lumbosacral transitional vertebra (LTV) and asymmetrical development of the hip joints in dogs.

Methods: A total of 4000 dogs which had been consecutively scored for canine hip dysplasia were checked for the presence of a LTV. A LTV was noted in 138 dogs and classified depending on the morphology of the transverse processes and the degree of contact with the ilium.

Results: In dogs with an asymmetrical LTV, the hip joint was significantly more predis-posed to subluxation and malformation on the side of the intermediate or sacral-like transverse process (p <0.01), on the side of the elevated pelvis (p <0.01), or when an asymmetrical LTV resulted in pelvic rotation on its long axis (p <0.01), whereas hip joint conformation was less affected on the side featuring a free transverse process (p <0.01).

Clinical significance: The results support our hypothesis that an asymmetrical LTV favours pelvic rotation over its long axis, resulting in inadequate femoral head coverage by the acetabulum on one side. Inadequate coverage of the femoral head favours subluxation, malformation of the hip joint, and secondary osteoarthritis. Asymmetrical hip conformation may therefore be the sequela of a LTV and mask or aggravate genetically induced canine hip dysplasia.

Etiopathogenesis of Canine Hip Dysplasia, Prevalence, and Genetics

First identified in 1935, canine hip dysplasia is thought to be the most common orthopedic condition diagnosed in the dog. It is most prevalent in large and giant breed dogs, with a complex polygenic mode of inheritance, and relatively low heritability. External factors including caloric intake when growing have a significant effect on phenotypic expression. Initial joint laxity progresses to osteoarthritis due to subluxation and abnormal wearing. Selective breeding programs to attempt to decrease prevalence have shown modest results so far.