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Congenital malformations of the lumbosacral vertebral column are common in neurologically normal French Bulldogs, English Bulldogs, and Pugs, with breed-specific differences
Abstract
Congenital vertebral malformations are common findings on diagnostic imaging of the vertebral column in "screw-tailed" brachycephalic dogs. The aims of this study were to evaluate the prevalence and anatomical characteristics of lumbosacral congenital vertebral malformations in French Bulldogs, English Bulldogs, and Pugs presenting for problems unrelated to spinal disease, as well as possible associations with the degree of tail malformation, lumbosacral intervertebral disc her-niation, or spondylosis deformans. In this retrospective cross-sectional study, CT scans of vertebrae L6 to S3 and of the coccygeal vertebrae were reviewed for type of congenital vertebral mal-formations (hemivertebrae, block vertebrae, lumbosacral transitional vertebrae, and spina bifida), lumbosacral intervertebral disc herniation, lumbosacral spondylosis deformans, and degree of tail malformation. In 76 (51.0%) of the 149 included dogs (53 French Bulldogs, 37 English Bulldogs, and 59 Pugs) at least one type of congenital vertebral malformations was found, with lumbosacral transitional vertebrae being the most common (34.2%). There was a significantly higher prevalence of lumbosacral transitional vertebrae (54.2%) and lower prevalence of hemivertebrae (1.7%) in Pugs compared to English (13.5% and 24.3%, respectively) and French Bulldogs (26.4% and 32.0%, respectively). Tail malformation was significantly more severe in dogs with evidence of hemivertebrae. Congenital vertebral malformations are a common finding in the lumbosacral ver-tebral column of French Bulldogs, English Bulldogs, and Pugs. These anatomical variances need to be considered when interpreting diagnostic studies and when planning for neurosurgical and neurodiagnostic procedures. Furthermore, this study suggests a possible association between the degree of tail malformation and lumbosacral hemivertebrae.
... IVDPs affecting the LS junction are poorly reported in CD dogs (4). A recent study found 72/149 dogs with LS IVDH within a population of neurologically normal FBs, English Bulldogs, and pugs; among FBs alone, the same study recorded a prevalence of 52.8% for LS IVDH (13). Another study reported a prevalence of 77.4% within a population of FBs, both with and without neurological disorders (14). ...
... Furthermore, the LS junction has been reported to be affected by congenital vertebral malformations (CVMs) in CD dogs based on CT examination and a possible association between CVMs and LS IVDP has been suggested (13,14). ...
... The results of this study support our hypothesis that LS IVDP is frequent in FBs presenting with thoracic or lumbar IVDE. LS IVDP affecting at least 1 position (canalar, intervertebral foraminal, or both) was observed in 91.3% of the FBs in our population, a percentage much higher than that reported in 2 previous studies [77.4%; (14) and 52.8% (13)] and more than half of the FBs in our population were graded ≥2. This difference may be due to several factors. ...
Introduction
Intervertebral disc protrusion (IVDP) is a neurological disorder commonly observed at the lumbosacral junction of old, medium-to-large breeds, non-chondrodystrophic dogs. Although uncommon, lumbosacral IVDP can also be seen in chondrodystrophic dogs, among them French Bulldogs (FBs) and could be associated with congenital vertebral malformations in this breed. This study aims to evaluate the prevalence, clinical features, and MRI characteristics of lumbosacral IVDP and congenital vertebral malformations in FBs diagnosed with thoracic or lumbar intervertebral disc extrusion (IVDE) and to evaluate the possible interference of the neurologic deficits related to chronic IVDP on neurological examination.
Materials and methods
This is a single-center, retrospective case series. A search for FBs diagnosed with IVDE affecting the thoracic or lumbar regions is done on the database of the AniCura I Portoni Rossi Veterinary Hospital (Zola Predosa, Bologna, Italy). Eligible dogs have a complete medical report and a high-field MRI of the lumbosacral junction. MRIs of the lumbosacral junction are evaluated to determine the position of IVDP, cranial intervertebral foraminal stenosis, and signs of nerve root involvement. Radiographs, when available, are reviewed to identify the presence of lumbosacral congenital vertebral malformations.
Results
Eighty FBs are included in the study. The prevalence of lumbosacral IVDP among FBs is 91.3%. Among FBs with lumbosacral IVDP, 45.0% show concurrent cranial intervertebral foraminal stenosis, 28.8% exhibit concurrent nerve root involvement, 56.2% appear to be asymptomatic for lumbosacral changes, while 15.1% manifest a decreased or absent withdrawal reflex as a supposed consequence of chronic lumbosacral IVDP. Congenital vertebral malformations are detected in 10 dogs.
Conclusion
The results of this study support the hypothesis that lumbosacral IVDP is frequent in FBs presenting with thoracic or lumbar IVDE. In over half the dogs lumbosacral IVDP appears to be asymptomatic; however, in other cases, chronic lumbosacral IVDP seems to cause neurological deficits that may lead to erroneous localization of acute IVDE, representing a confounding factor for clinicians.
... In veterinary medicine, case reports or small case series have been reported, and the prevalence of SB is estimated to be about 0.007% in dogs [10] and 0.009% in cats [11]. In small animals, multiple genetic and environmental interactions seem to contribute to SB [10,12]. ...
... In veterinary medicine, case reports or small case series have been reported, and the prevalence of SB is estimated to be about 0.007% in dogs [10] and 0.009% in cats [11]. In small animals, multiple genetic and environmental interactions seem to contribute to SB [10,12]. The genetic component is confirmed by overrepresentation in certain breeds of cats (Manx cat) [11,13] and dogs [bulldogs and pugs [10] and German shepherds [14,15], whereas supplementation with antifungal agents, such as griseofulvin [16] and ethylenethiourea [17], and toxic agents, such as methylmercury and hydroxyurea, in pregnant cats has been associated with increased SB [18]. ...
... In small animals, multiple genetic and environmental interactions seem to contribute to SB [10,12]. The genetic component is confirmed by overrepresentation in certain breeds of cats (Manx cat) [11,13] and dogs [bulldogs and pugs [10] and German shepherds [14,15], whereas supplementation with antifungal agents, such as griseofulvin [16] and ethylenethiourea [17], and toxic agents, such as methylmercury and hydroxyurea, in pregnant cats has been associated with increased SB [18]. ...
Lower urinary tract disease (LUTD) includes abnormalities in the structure and function of the bladder and the urethra. LUTD caused by neurological disease is defined neurogenic bladder (NB). The integrity of the central nervous system (CNS) and peripheral nervous system (PNS) is required to explicate normal micturition, maintaining the proper function of bladder and urethra. The location and type of neurological lesions influence the pattern of clinical manifestations, potential treatment, and prognosis. Though, in dogs and cats, spinal cord injury is considered mainly responsible for bladder and/or urethra incompetence, other disorders, congenital or acquired, involving CNS or PNS, could play a role in NB. In veterinary medicine, the information about the epidemiology, prevalence, etiopathogenesis, diagnosis and treatment of NB are scattered. The aim of this study is to provide an overview of the epidemiology, prevalence, clinical findings, diagnosis and prognosis for NB in dogs and cats compared with humans.
... Recent studies report a higher incidence of orofacial and vertebral malformations in purebreds, especially in brachycephalics such as English and French Bulldogs, Pugs, and Boston Terriers (2,4,6,7). ...
... Congenital vertebral malformations are so common findings on diagnostic imaging of the vertebral column in "screw-tailed" brachycephalic patients that 51% of the dogs evaluated in a study had evidence of one or more lumbosacral congenital vertebral malformations. These alterations had a high prevalence even in neurologically normal French Bulldogs, English Bulldogs, and Pugs (6). ...
... Although these changes are diagnosed in animals without clinical signs, Vertebral body malformations are suggested to change spinal biomechanics that can lead to premature degeneration of adjacent intervertebral disk (6). In one study, French Bulldogs showed 0.89 times the odds of being diagnosed with at least a disease compared to other breeds (29). ...
The popularity of brachycephalic dogs has increased in recent years due to their docile temperament and peculiar features. The historical inbreeding and consequent lack of genetic diversity involved in the development of these breeds led to an increase in the manifestation of deleterious genes that may lead to malformations. In addition, there are serious health issues intrinsic to the conformation, mainly attributed to these extreme characteristics. Therefore, this retrospective study aimed to observe the frequency of malformations in brachycephalic dogs compared to the pure and mixed breeds (MB). The medical records of pregnant bitches admitted at the Service of Obstetrics and Animal Reproduction (SORA) from January 2017 to December 2021 were retrieved from the hospital's computer system and analyzed one by one. Seven hundred sixty-eight neonates born from 168 litters were included in this study. Of these litters, 72.6% (122/168) were brachycephalic. Malformations were found in 52 puppies, with an incidence of 6.77% (52/768). Of the 32 litters that produced malformed puppies, 28 were brachycephalic (87.5%). In total, 23 types of malformations were registered, the most common being cleft palate (1.30%) and anasarca (1.17%). Ten of the puppies (10/52; 19.23%) presented two or more associated malformations. Bitches above 7 years were more prone to present malformed puppies in their litters. Brachycephalic breeds were 3.03 times more likely to present malformed neonates when compared to other breeds; the odds ratio increased to 5.07 when modern brachycephalic was compared to ancestral brachycephalic. Regarding the mode of delivery, elective cesarean sections accounted for 66.6% of births while 19.64% were eutocic vaginal deliveries, and 13.69% were dystocic. The presence of malformed puppies in a litter causes suffering for the owner, the bitch and for the puppy itself, therefore, the veterinarian plays a key role in this scenario. Knowledge about congenital abnormalities, their causes, diagnosis, and approach is essential to reduce the incidence of malformations and improve the quality of life of these animals.
... Almost all studies investigating CVBM are retrospective, describing a defined segment of the vertebral column and commonly include a low number of patients. [2][3][4][5]8,9,15,17,19,21 The aim of the study was to prospectively evaluate the associations between CVBM along the entire vertebral column and tail malformation, neurological deficits, as well as occurrence of accompanying orthopaedic diseases, specifically HD and patellar luxation in a cohort of brachycephalic dogs from Germany. The hypotheses of the study were: (i) Distribution and types of CVBM in a German brachycephalic dog population do not differ from reported results in literature. ...
... To compare our results regarding the types of vertebral malformation with relevant veterinary literature, 2,4,8,9,15,18,25 we used the classification proposed by Gutierrez-Quintana et al. 4 In addition to the used classification we investigate two types of vertebral malformations not described in the used classification: dorsal wedge shape vertebra and ventrolateral wedge shape vertebra. During the writing process of this paper, the research group who published the first classification of vertebral malformation completed their scheme with the ventro lateral wedge shape vertebra. ...
... The present study included more dogs with neurological deficits (55% [145/265]) compared to other studies. 4,6,15,19,22 The most likely explanation for this difference is the prospective design of the investigation, different inclusion criteria and neurological examination under supervision of a neurologist of all participating dogs which might have resulted in the higher sensitivity to detect subtle paresis. ...
Background:
Congenital vertebral body malformations (CVBMs) have retrospectively been investigated in British and American canine populations. This study prospectively evaluates occurrence, localization, type and characteristic of CVBM along the entire vertebral column in a cohort of French Bulldogs, English Bulldogs and Pug dogs from Germany.
Methods:
Prospective clinical and radiological screenings for CVBM were performed in brachycephalic dogs presented for reasons unrelated to neurological problems. Neurological and orthopaedic examinations as well as radiographs in two orthogonal planes of the entire vertebral column including the tail were performed in all dogs. Cobb angle and vertebral step were determined. Associations between CVBM, tail malformation, neurological deficits and occurrence of concurrent orthopaedic diseases were investigated.
Results:
A total of 707 VBMs were identified in the whole vertebral column of 169 of 265 brachycephalic dogs. The most common types of CVBMs were ventral wedge shape (48%), dorsal wedge shape (14%) and shortened vertebral body (14%). A new type of malformation was investigated: dorsal wedge shape vertebrae. There was significant association between severe tail malformations with CVBM. Neurological deficits were significantly associated with ventrolateral wedge shape, dorso lateral hemivertebrae, Cobb angle > 30% and vertebral step ≥1.75 mm. Orthopaedic conditions were not significantly associated with CVBM.
Conclusion:
Kyphotic Cobb angle and vertebral step are radiological findings associated with neurological deficits. We propose severe tail malformation as an easy and accurate selection factor for determining breeding dogs.
... Chondrodystrophic breeds are predisposed to the occurrence of vertebral malformations, such as hemivertebrae, block vertebrae, transitional vertebrae, spina bífida, among others. Such anatomical anomalies can be asymptomatic or predispose to the occurrence of neurological signs, by vertebral dislocation or spinal cord compression (Ryan et al., 2017;Bertram et al., 2019). Through statistical evaluation, in the presente study, the thoracolumbar region was the most affected by altered vertebral conformations, with the most frequent hemivertebrae. ...
... According to this study, extrusion was more prevalent than protrusion for TL, while protrusion was more evident in the LS region compared to extrusion. The higher occurrence of thoracolumbar disk extrusion may be related, in part, to its predisposition to chondrodystrophic animals (Jeffery et al., 2013), since it was the most studied group of animals, as well as having greater vertebral anatomical changes that favor the process of instability and overloading of the intervertebral disk (Ryan et al., 2017;Bertram et al., 2019). Hansen I is the extrusion of the nucleus pulposus of the intervertebral disk, arising from a chondroid metaplasia and, therefore, is mostly related to chondrodystrophic dogs (Fenn et al., 2020), as seen for both study regions, although its occurrence has also been identified in non-chondrodystrophic patients, even if in smaller proportions. ...
... or valued by many breed enthusiasts, and popular with the public, today, despite growing evidence of their associations with disease [6,[10][11][12][13][14]. Indeed, brachycephalic breeds, including the English Bulldog, are currently experiencing a surge in popularity, paradoxically despite increasing evidence and awareness of serious health problems linked to their physical appearance, such as respiratory compromise [12,14], spinal defects [15], dystocia [11], ocular disorders [13,16,17] and skin disease [18]. From the start of the twentieth century, veterinary canine specialists freely acknowledged the (English) Bulldog's predilection to conformation-related disease [3,19]. ...
... At the grouped disorder level, marked protections (OR < 0.5) were reported for appetite disorder (OR 0.43), spinal cord disorder (0.31) and dental disorder (0.25). Some of these protections are somewhat surprising; for example, given the breed's documented high incidence of hemivertebrae and other vertebral malformations [15,[71][72][73], it is unexpected but reassuring to find that this does not apparently translate into a high level of spinal cord disorder, and may be explained by previous findings that hemivertebrae is more commonly associated with a neurologically normal phenotype in English Bulldogs than for Pugs (Ryan et al., 2017). It is also surprising that a breed with a high prevalence of many other descriptors for skin disease has an apparent protection for pruritus: perhaps this descriptor was subsumed within other more clinically precise descriptors, such as dermatitis or atopic dermatitis, and hence appears artefactually low. ...
Background
The English Bulldog has risen sharply in popularity over the past decade but its distinctive and extreme conformation is linked to several serious health conditions. Using multivariable analysis of anonymised veterinary clinical data from the VetCompass Programme, this study compared the odds of common disorders between English Bulldogs and all remaining dogs in the UK during 2016.
Results
From 905,544 dogs under veterinary care during 2016, the analysis included a random sample of 2,662 English Bulldogs and 22,039 dogs that are not English Bulldogs. English Bulldogs had 2.04 times the odds of diagnosis with ≥ 1 disorder than dogs that are not English Bulldogs (95% confidence interval [CI] 1.85 to 2.25). At a specific-level of diagnostic precision, English Bulldogs had increased odds of 24/43 (55.8%) disorders. These included: skin fold dermatitis (odds ratio [OR] 38.12; 95% CI 26.86 to 54.10), prolapsed nictitating membrane gland (OR 26.79; 95% CI 18.61 to 38.58) and mandibular prognathism (OR 24.32; 95% CI 13.59 to 43.53). Conversely, English Bulldogs had significantly reduced odds of 6/43 (14.0%) disorders. These included: retained deciduous tooth (OR 0.02; 95% CI 0.01 to 0.17), lipoma (OR 0.06; 95% CI 0.01 to 0.40) and periodontal disease (OR 0.23; 95% CI 0.18 to 0.30). At a grouped-level of diagnostic precision, English Bulldogs had significantly increased odds of 17/34 (50.0%) disorders. These included: congenital disorder (OR 7.55; 95% CI 5.29 to 10.76), tail disorder (OR 6.01; 95% CI 3.91 to 9.24) and lower respiratory tract disorder (OR 5.50; 95% CI 4.11 to 7.35). Conversely, English Bulldogs had significantly reduced odds of 3/34 (8.8%) disorders. These were: dental disorder (OR 0.25; 95% CI 0.20 to 0.31), spinal cord disorder (OR 0.31; 95% CI 0.14 to 0.71) and appetite disorder (OR 0.43; 95% CI 0.20 to 0.91).
Conclusions
These results suggest that the health of English Bulldogs is substantially lower than dogs that are not English Bulldogs and that many predispositions in the breed are driven by the extreme conformation of these dogs. Consequently, immediate redefinition of the breed towards a moderate conformation is strongly advocated to avoid the UK joining the growing list of countries where breeding of English Bulldogs is banned.
... SB can also be classified as closed (occulta) or opened (manifesta/aperta) if there is communication between the neural tissue and the external environment. SA is occasionally reported in humans with SB occulta (5,(18)(19)(20)(21). ...
Two boxer dogs from the same litter were presented at 3 months of age for urinary and fecal incontinence. Both dogs had an abnormal tail consisting of a small stump, an atonic anal sphincter, and absent perineal reflex and sensation. Neurological evaluation was indicative of a lesion of the cauda equina or sacral spinal cord. Radiology and CT scan of the spine displayed similar findings in the two dogs that were indicative of sacral agenesis. Indeed, they had 6 lumbar vertebrae followed by a lumbosacral transitional vertebra, lacking a complete spinous process, and a hypoplastic vertebra carrying 2 hypoplastic sacral transverse processes as the only remnant of the sacral bone. Caudal vertebrae were absent in one of the dogs. On MRI, one dog had a dural sac occupying the entire spinal canal and ending in a subfascial fat structure. In the other dog, the dural sac finished in an extracanalar, subfascial, well-defined cystic structure, communicating with the subarachnoid space, and consistent with a meningocele. Sacral agenesis-that is the partial or complete absence of the sacral bones-is a neural tube defect occasionally reported in humans with spina bifida occulta. Sacral agenesis has been described in human and veterinary medicine in association with conditions such as caudal regression syndrome, perosomus elumbis, and Currarino syndrome. These neural tube defects are caused by genetic and/or environmental factors. Despite thorough genetic investigation, no candidate variants in genes with known functional impact on bone development or sacral development could be found in the affected dogs. To the best of the authors' knowledge, this is the first report describing similar sacral agenesis in two related boxer dogs.
... For Taylor (12), spina bifida can be observed in any region of the spine, although its largest sample is described in the lumbar caudal and lumbosacral segments. The prevalence of the region of most common occurrence of the disease for Bertram et al. (10) was 50% in the third sacral vertebra, followed by 37.5% and 12.5% in the second and first sacral regions, respectively. In the case reported here, the animal presented spina bifida in the thoracic region, more specifically in the region between the T5, T6, T7, T8 and T9 vertebrae, this form also seen and described by Miranda et al. (3). ...
The aim of this report is to describe a presumptive diagnosis of spina bifida in a mixed breed dog, due to previous diagnostic inconsistencies. Spina bifida is an uncommon congenital anomaly characterized by poor bone formation due to incomplete closure or the absence of the dorsal arch of the vertebral structure during the process of embryogenesis. Animals with this condition may have difficulties in the locomotion process, which constantly threatens the quality and survival of those affected. Spina bifida can present itself in four different forms and degrees. A 5-month-old mixed breed dog was assisted at a veterinary clinic in Conselheiro Lafaiete/MG with difficulties in the locomotion process and previous diagnostic inconsistencies in other veterinary services. On physical examination, he had kyphosis in the thoracic region and decreased proprioceptive capacity in the hind limbs. After radiographs were taken, morphological thoracic alterations were observed in the segment between the T5 to T9 vertebrae, with duplicated spinous processes and a decrease in the dimensions of the intervertebral space. The radiographic examination suggested presumptive evidence of thoracic spina bifida due to the unavailability of the tutor to perform more sensitive exams such as tomography and magnetic resonance. Therefore, drugs for pain and neuropathic control such as gabapentin and pregabalin were prescribed, at different times, until new recommendations, which have shown therapeutic efficacy to the patient. Currently, the patient uses a wheelchair adapted for locomotion due to the loss of movement of the hind limbs, in addition to weekly physical therapy follow-up and acupuncture sessions.
... These conditions occur as a result of a failure of normal formation, segmentation, differentiation, or union of structures during embryologic development stages (Auer & Stick, 2018;Castriota-Scanderbeg & Dallapiccola, 2006). Hemivertebra is a condition in which asymmetric vertebral body formation occurs so, a part of the vertebral body is deficient (Bertram et al., 2019;White & Goldberg, 2022). Depending on hemivertebra location and severity, it may be associated with moderate to severe angulation of the normal spine alignment with or without neurologic gait deficits (Auer & Stick, 2018;Haussler). ...
Thoracic hemivertebra is one of the rare congenital vertebral anomalies in horses resulting in vertebral column deformity with or without neurological signs. A nine-month-old Racking filly was presented with a distinct bump over the back region. This bump was apparent at birth and has been increasing in size. Clinical examination revealed a painless kyphoscoliosis over the thoracic vertebrae with mild ataxia and abnormal gait of hindlimbs. In plain lateral radiographs of thoracic vertebrae, hemivertebrae were seen in the 13th-15th thoracic vertebrae. At myelography performed under general anaesthesia, the ventral and dorsal aspects of the contrast medium column were narrowing at the level of the 13th-14th thoracic vertebrae, and no sign of contrast medium after the 14th thoracic vertebra that represents spinal cord compression. Little information about hemivertebra in horses exists and a better understanding of hemivertebra etiology is required.
... For dogs in the BOAS group, sexually intact males were most common (n = 15), followed by neutered males, sexually intact females, and neutered females (5 each). For dogs in the BDWB group, neutered females were most common (n = 11), followed by neutered males (8), sexually intact males (6), and sexually intact females (1). Median age for dogs in the BOAS group was 2.5 years (IQR, 0.75 to 7.9 years), median body weight was 12.2 kg (IQR, 5 to 36 kg), and median BCS was 4 (IQR, 2 to 7). ...
OBJECTIVE
To assess the prevalence of bronchial wall thickening (BWT) and collapse in brachycephalic dogs with and without brachycephalic obstructive airway syndrome (BOAS) and in nonbrachycephalic dogs.
ANIMALS
85 dogs with no history of lower respiratory tract disease that underwent CT of the thorax.
PROCEDURES
Electronical medical records for March 2011 through August 2019 were reviewed to identify brachycephalic dogs with BOAS (BOAS group) and brachycephalic dogs without BOAS (BDWB group) that did not have any evidence of lower respiratory tract disease and had undergone thoracic CT. A population of nonbrachycephalic dogs of similar weight (control dogs) was also retrospectively recruited.
RESULTS
BWT was identified in 28 of 30 (93.3%; 95% CI, 80.3% to 98.6%) dogs in the BOAS group, 15 of 26 (57.7%; 95% CI, 38.7% to 75.0%) dogs in the BDWB group, and 10 of 28 (35.7%; 95% CI, 20.1% to 54.2%) control dogs. On multivariable analysis, only brachycephalic conformation ( P < 0.01) and body weight ( P = 0.02) were significantly associated with the presence of BWT. Bronchial collapse was identified in 17 of 30 (56.7%; 95% CI, 39.0% to 73.1%) dogs in the BOAS group, 17 of 26 (65.4%; 95% CI, 46.3% to 81.3%) dogs in the BDWB group, and 3 of 28 (10.7%; 95% CI, 3.1% to 25.9%) control dogs. On multivariable analysis, only brachycephalic conformation was significantly ( P < 0.01) associated with the presence of bronchial collapse.
CLINICAL RELEVANCE
A relationship between brachycephalic conformation and body weight with BWT was established, with heavier dogs having thicker bronchial walls. However, further studies are required to investigate the cause. Bronchial collapse was also more common in dogs with brachycephalic conformation, which is in agreement with the previously published literature.
... 37,38 For breeds predisposed to transitional vertebrae, such as French bulldogs (thoracolumbar) and German shepherds (lumbosacral), additional imaging of the spine may be warranted before vigorous activities such as agility, apprehension sports, or training as a working dog. [39][40][41][42][43] Instability in these areas may increase risk of degenerative joint changes, debilitating pain, and/or neurologic impairment. 43 The radiographs act as both a screening tool and a baseline for comparison to future diagnostic imaging. ...
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.
... Some studies in humans 26,27 and dogs [28][29][30] show association between variations of the LS articulation and the development of lesions, with the potential for the absence of clinical signs in individuals with anatomic variations. 31 In the present study, detailed characterization of individual LS conformation was provided on the basis of vertebral column features identified with 2 complementary diagnostic imaging modalities used to image standing horses. Our findings represent a preliminary step toward further assessments of relationships that may exist between these anatomic variants and LS pathological findings or performance. ...
Objective:
To describe scintigraphic and transrectal ultrasonographic anatomic variants of the lumbosacral (LS) articulation in horses and to determine the agreement between results obtained with each imaging modality.
Animals:
243 horses (81 Selle Français Warmbloods, 81 French Standardbred Trotters, and 81 Thoroughbreds).
Procedures:
A retrospective search of clinical records was conducted to identify horses that had undergone nuclear scintigraphy and transrectal ultrasonography of the LS region of the vertebral column between January 2016 and December 2019. Scintigraphic images were evaluated by 2 observers blinded to the other's results for classification of LS articulation anatomic variants (scintigraphic type); intra- and interobserver agreement were determined. Ultrasonographic images were evaluated for classification of LS intervertebral symphysis anatomic variant (ultrasonographic grade) by 1 observer blinded to horses' identities and scintigraphic findings; agreement analysis was performed between scintigraphic type and ultrasonographic grade. Descriptive and statistical analyses were performed to describe distribution of anatomic variants.
Results:
The scintigraphic classification system (scintigraphic type) had excellent intra- and interobserver agreement. Agreement between results for scintigraphic type and ultrasonographic grade was moderate (κ = 0.61; 95% CI, 0.52 to 0.70). Anatomic variants of the LS articulation were observed in all groups. The distribution of variants differed significantly among breeds but not sexes.
Clinical relevance:
Anatomic variations of the LS articulation in horses must be known to avoid misinterpreting them as clinically meaningful findings. Further research is needed to determine potential relationships between these anatomic variants and LS lesions, their clinical manifestations, and their influence on athletic performance.
... Comparing relative risks between the breed groups for a series of common disorders based on a single large dataset derived from a random sample of dogs facilitates a more holistic view of health and has highlighted a number of interesting and novel health features of French Bulldogs that are discussed in more detail below. There is substantial published literature supporting several serious health issues the French Bulldog [13,14,19,[44][45][46]. The UK Kennel Club has such serious concerns for the health of the French Bulldog that the breed is included as a Category 2 on its Breed Watch system, with points of concern for special attention by judges that include respiratory distress, dermatitis in skin folds, prominent eyes, pinched nostrils, incorrect bite and short neck [47]. ...
Background
The French Bulldog is a highly popular dog breed but is linked with many serious health issues. A holistic view of breed health in French Bulldogs would assist efforts to appreciate the overall health strengths and weaknesses in the French Bulldog and to take appropriate steps to mitigate these.
Based on random sampling of French Bulldogs and non-French Bulldogs under primary veterinary care during 2016 within the VetCompass Programme, a cohort study design was used to estimate the one-year (2016) period prevalence of the most commonly diagnosed disorders in each group. Risk factor analysis used multivariable logistic regression modelling methods.
Results
The analysis included 2,781 French Bulldogs and 21,850 non-French Bulldogs. French Bulldogs were younger (1.51 years, IQR 0.86 – 2.77 vs. 4.48 years, IQR 1.94 – 8.14) ( p < 0.001) and lighter (12.45 kg, IQR 11.00 – 14.03 versus 13.80 kg, IQR 8.10 – 25.12) ( p < 0.001) than non-French Bulldogs. Of 43 common specific-level disorders across both groups, French Bulldogs had significantly increased adjusted odds of 20/43 (46.5 %) disorders and significantly reduced adjusted odds of 11/43 (25.6 %) disorders compared to non-French Bulldogs. Highly predisposed disorders in French Bulldogs included stenotic nares (OR 42.14; 95 % CI 18.50 to 95.99; p < 0.001), Brachycephalic Obstructive Airway Syndrome (OR 30.89; 95 % CI 20.91 to 45.64; p < 0.001), aural discharge (OR 14.40; 95 % CI 9.08 to 22.86; p < 0.001), skin fold dermatitis (OR 11.18; 95 % CI 7.19 to 17.40; p < 0.001) and dystocia (OR 9.13; 95 % CI 5.17 to 16.13; p < 0.001). At a grouped-level of diagnostic precision, French Bulldogs had increased adjusted odds of 12/32 (37.5 %) disorders and reduced adjusted odds of 6/32 (18.8 %) disorders compared to non-French Bulldogs.
Conclusions
These results identified ultra-predispositions with worryingly higher odds in French Bulldogs for several disorders, suggesting that the health of French Bulldogs has diverged substantially from, and may be lower than, the health of the wider non-French Bulldog population. Many of these predispositions are closely associated with the conformational extremes that define the French Bulldog breed. Shifting the typical conformation of the French Bulldog population towards a more moderate phenotype is proposed as a logical opportunity to reduce the serious health issues endemic in the French Bulldog breed.
... C ongenital vertebral malformations (CVMs) are common incidental findings on diagnostic imaging of the thoracic vertebral column in "screw-tailed" brachycephalic breeds (1,2). Although the true prevalence of CVMs in such breeds is unknown, previous studies have indicated this could be as high as 96% in pugs (2). ...
The aim of this study is to report chronic complications (> 2 mo after surgery) following spinal segmental stabilization (SSS) to treat myelopathy associated with thoracic congenital vertebral malformations in brachycephalic dogs. Follow-up medical records (years 2006 to 2020) of 12 cases that underwent SSS at 3 university hospitals were retrieved and analyzed with a minimum follow-up period of 1 y. Five dogs showed no chronic complications and 7 dogs had chronic complications which are reported here. This case series demonstrates that the rate of chronic complications associated with SSS was high (58%) but most of these were minor and did not require revision surgery.
... Congenital vertebral malformations are developmental abnormalities of the vertebrae that occur frequently in the thoracic column (1,2). These vertebral malformations may be caused by congenital absence of vertebral vascularization, genetic defects, or teratogenic insult to active cartilaginous proliferation (2-4). ...
A 2-year-old Maltese was presented with wobbly gait of the pelvic limbs. Based on imaging examinations, a diagnosis of congenital malformation at T5–T8 and severe kyphosis causing spinal cord compression at T6–T7 was made. Dorsal laminectomy and stabilization of T6 and T7 vertebrae were performed. As the size of the vertebrae was small and they were severely deformed, novel custom-made titanium implants were used for spinal stabilization. Clinical signs were resolved 2 weeks after surgery. Although radiographic examination 373 days after surgery showed slight loosening of implants, post-operative course remained uneventful. This report describes the use of novel custom-made titanium implants for spinal fixation surgery in a dog.
... Spinal disease has been reported as the second most common cause of death of French bulldogs in primary care practice (O'Neill et al. 2018). Thoracolumbar and cervical IVDE are the most common spinal disorders in French bulldogs with other commonly observed spinal abnormalities including thoracic and lumbosacral vertebral malformations and spinal arachnoid diverticula (Mayousse et al. 2017, Bertram et al. 2019. Studies have demonstrated thoracic hemivertebra in 78 to 94% of neurologically normal French bulldogs (Moissonnier et al. 2011, Ryan et al. 2017) and one study reported kyphosis in 33% of French bulldogs without neurological signs and in 57% of French bulldogs with thoracolumbar IVDE (Inglez de Souza et al. 2018). ...
Objectives
To identify the prevalence of recurrence of clinical signs after initial successful decompressive surgery for intervertebral disc extrusion in French bulldogs.
Materials and Methods
A medical record search was performed to identify French bulldogs that experienced an initial successful outcome after surgery for thoracolumbar or cervical intervertebral disc extrusion. Collected information included signalment, neurological examination findings, intervertebral disc extrusion location, presence of vertebral malformations, kyphosis, type and extent of surgery. Decompressive surgery was not followed by extensive prophylactic fenestrations. Follow‐up information was retrieved from medical records and telephone interviews with referring veterinary surgeons.
Results
Eighty‐four French bulldogs with thoracolumbar (n=55) or cervical (n=29) intervertebral disc extrusion were included. Forty‐three (51%) dogs that had decompressive surgery for thoracolumbar (n=29) or cervical (n=14) intervertebral disc extrusion suffered recurrence of signs. The median time between decompressive surgery and recurrence of clinical signs was 9 months and 21 days. Of the 29 dogs suffering recurrence of clinical signs following surgery for thoracolumbar intervertebral disc extrusion, 24 returned for recurrence of clinical signs localised to the thoracolumbar segments, while five returned for recurrence of signs localised to the cervical region. Of the 14 dogs who suffered recurrence of signs following surgery for cervical intervertebral disc extrusion, nine returned for signs localised to the cervical region, while five returned for clinical signs localised to the thoracolumbar region.
Clinical Significance
This study suggests a high rate of late onset recurrence of clinical signs after decompressive surgery for intervertebral disc extrusion in French bulldogs. This information can aid in the management of owner expectations.
... The mechanisms resulting in this characteristic curly tail, however, are possibly different among breeds. 2,3 Their increase in popularity has been associated with welfare concerns associated with their anatomical conformation. 4,5 "Screw-tailed" brachycephalic dogs are prone to suffer from breathing problems, ophthalmologic disorders, skin disease, and several spinal conditions. ...
Background:
Although thoracic hemivertebra can cause neurological signs, they occur commonly in neurologically normal dogs.
Objectives:
To evaluate whether computed tomography (CT) findings and factors associated with signalment can be used to differentiate between dogs with and without neurological signs associated with hemivertebra.
Animals:
One hundred sixty dogs with ≥1 hemivertebrae were retrospectively studied. This group consisted of 40 dogs with clinical signs caused by hemivertebra and 40 French Bulldogs, 40 Pugs, and 40 English Bulldogs that underwent CT for reasons unrelated to neurological disease.
Methods:
All dogs underwent CT and affected dogs also underwent magnetic resonance imaging. All CT studies were randomly evaluated by an observer blinded to signalment and clinical status. The following variables were evaluated: presence, number, location, and subtype of hemivertebra; presence of vertebral subluxation; severity of vertebral canal stenosis; presence, location, and severity of kyphosis, and number of vertebrae involved in the kyphotic segment. Statistical modeling was performed to identify factors associated with clinical status.
Results:
Pug breed (odds ration [OR], 10.8; P = .01), more severe kyphosis (OR, 1.1 per grade increase; P < .001), fewer instead of more observed hemivertebrae (OR, 0.8; P = 0.03), and ventrolateral hypoplasia hemivertebra subtype (OR, 4.0; P = .011) were associated with higher likelihood of neurological disease. A Cobb angle of 34.5 degrees corresponded with the highest combined sensitivity and specificity to differentiate between clinically affected and unaffected dogs.
Conclusions and clinical importance:
The variables identified could aid in differentiating between clinically relevant and irrelevant hemivertebra in small breed brachycephalic dogs.
... While efforts have been made to supplement this shortcoming with other methods, such as a retinoic acid induced MMC in fetal rats [22], other large animal alternatives come up short. While dogs have been proposed as a natural model of spina bifida given the prevalence of spinal dysraphism in the English bulldog and similar breeds [23], and with recent surgical ex utero repairs of spina bifida being effective in both german shepherds [24] and bull dogs [25], the dog model does not have an extensive history of use as an in utero surgical model compared to the fetal lamb. ...
BACKGROUND/PURPOSE:
In 2004, a heritable occurrence of spina bifida was reported in sheep on a farm in the United States. We maintained and characterized the spina bifida phenotype in this flock to assess its potential as an alternative surgical model.
METHODS:
A breeding strategy was developed in which the sheep were crossed to maintain or increase the occurrence of spina bifida. Measurements and observations were recorded regarding lesion size, birthweight, ambulatory capacity, or urological function, and necropsies were performed on spina bifida afflicted lambs in conjunction with magnetic resonance imaging to determine the character of the spina bifida defects and assess the presence of Chiari-like malformations or hydrocephalus.
RESULTS:
The defects were observed to be more prevalent in ram lambs, and the rate of spina bifida per litter could be increased through backcrossing or by selection of a productive ewe breed. The lambs displayed a range of ambulatory and urological deficits which could be used to evaluate new fetal repair methodologies. Finally, affected lambs were shown to demonstrate severe Chiari malformations and hydrocephalus.
CONCLUSIONS:
We have determined that use of these sheep as a natural source for spina bifida fetuses is feasible and could supplement the deficits of current sheep models for myelomeningocele repair.
LEVEL OF EVIDENCE:
Level IV.
Thoracic hemivertebra is a rare congenital vertebral malformations in horses resulting in vertebral column deformity with or without neurological signs. A 9‐month‐old Racking filly was presented with a distinct lump over the back region. This lump was apparent at birth and had been increasing in size. Clinical examination revealed painless kyphoscoliosis over the thoracic vertebrae with mild hindlimb ataxia and gait abnormality. Plain radiographs of the vertebral column showed 13th–16th thoracic hemivertebrae. Myelography was performed under general anaesthesia. The ventral and dorsal aspects of the contrast medium column were narrowed at the level of the 13th–14th thoracic hemivertebrae. The contrast medium was not seen caudally, suggesting spinal cord compression. Little information about hemivertebra in horses exists, and a better understanding of hemivertebra aetiology is required.
Lumbosacral osteochondrosis has been previously described in large breed dogs with variable clinical signs. Its CT features are a contour defect at the dorsal aspect of either vertebral endplate, commonly with an adjacent fragment. Descriptions of this condition have not been previously published in an increasingly popular breed, French Bulldogs. Aims of this retrospective, descriptive, single center study were to evaluate CT lumbosacral abnormalities and the frequency of lumbosacral endplate contour defect in a large sample of French Bulldogs. The presence and location of lumbosacral endplate contour defect and the presence of a concurrent osseous fragment were recorded. Other abnormal CT findings such as L7-S1 disc herniation, cauda equina nerve roots compression or thickening, disc mineralization, endplate sclerosis, spondylosis deformans, S1 articular processes hypertrophy, transitional vertebrae, hemivertebrae, spina bifida, and block vertebrae were recorded. Lumbosacral CT abnormalities were present in 91.8% of dogs (168/183). The most common abnormality was an L7-S1 dorsal disc herniation (77.4%, 130/168). Among dogs with lumbosacral abnormalities, the frequency of a lumbosacral endplate contour defect was 47% (79/168). It mostly involved L7 (78.5%, 62/79) at its dorsolateral aspect (61.3%, 38/62). A mineralized fragment was identified in 62% of the defects (49/79). Endplate contour defects were most frequently seen with a concurrent disc herniation (93.7%, 74/79) causing nerve root compression in 63.3% (50/79) and with sclerosis (65.8%, 52/79). There was no definitive evidence of a relationship with clinical presentation in this sample of French Bulldogs; therefore, this finding should be interpreted with caution. The etiology remains unclear.
Se realizó un estudio anatómico comparativo de los diferentes segmentos vertebrales que forman parte de la columna vertebral del perro (Canis lupus familiaris) y el gato (Felis silvestris catus). La columna vertebral es un conjunto de estructuras óseas que cumplen un rol esencial en la estabilización, el equilibrio y la distribución de fuerza en el cuerpo. Anatómicamente, la columna vertebral se subdivide en cinco porciones: la cervical, la torácica, la lumbar, la sacra y la coccígea. Estas presentan diversas características que incluso se diferencian entre especies. La importancia de comprender las características propias de la columna vertebral de animales menores se fundamenta en que son las mascotas de mayor atención en la clínica veterinaria, donde en muchas ocasiones es necesaria la realización de exámenes complementarios o procedimientos quirúrgicos frente a la presencia de una lesión o enfermedad. Existe una variedad de literatura anatómica sobre segmentos vertebrales en animales menores, pero no son muchos los autores que describen comparaciones directas entre ambas especies. Los resultados del presente estudio demostraron una serie de diferencias anatómicas que permiten entender particularidades de cada una de estas especies, y que pueden ser de utilidad clínica para médicos veterinarios de animales menores.
Zusammenfassung
Gegenstand und Ziel Ziel der Studie war es, im Rahmen einer Online-Umfrage für Mops-Besitzer das Vorkommen und die Wahrnehmung für das durch die Zucht bedingte brachyzephale obstruktive Atemwegssyndrom (BOAS) zu ermitteln.
Material und Methoden Es wurde ein digitaler Fragebogen für Besitzer zur Verbreitung und Beantwortung über soziale Medien erstellt und ausgewertet.
Ergebnisse Insgesamt wurde der Fragebogen von 1220 Mops-Besitzern beantwortet. 1073 Hunde waren nicht operiert. Laut der Besitzer zeigen 32 % (344/1073) der Tiere, bei denen bisher keine OP zur Erweiterung der Atemwege durchgeführt wurde, in Ruhe „leichte“ und 3 % (34/1073) „deutliche“ Atemgeräusche. Die wahrgenommenen Atemgeräusche wurden von 86 % (326/378) der Besitzer als „normal, rassetyptisch“ und von 14 % (51/378) als „Erkrankung“ klassifiziert. 20 % (210/1073) der Tiere scheinen bei körperlichen Belastung nach kurzer Zeit „etwas“ und 5 % (57/1073) scheinen „häufig müde und schnell außer Atem“ zu sein. 24 % (245/1220) aller Tiere leiden u. a. an Augen-, 10 % (122/1220) an Haut- und 11 % (134/1220) an Wirbelsäulenerkrankungen.
Schlussfolgerung Aus der Umfrage wird deutlich, dass mehr als die Hälfte der Mopsbesitzer bei ihren Tieren klinische Anzeichen von BOAS und/oder weiteren rassespezifischen Erkrankungen wahrnehmen, ein Großteil diese aber als unproblematisch ansieht.
Klinische Relevanz Daraus ergibt sich, dass die mit der Brachyzephalie einhergehenden, klinischen Einschränkungen der Tiere häufig nicht als Erkrankung wahrgenommen und unterschätzt werden.
Previous studies have reported evidence that thoracolumbar articular process hyperplasia and degenerative joint disease may be a cause of stenotic myelopathy in large breed dogs; however, detailed descriptions of imaging characteristics are currently lacking. The aim of this retrospective, multi‐center, case series report was to describe imaging findings in six large breed dogs diagnosed with thoracolumbar articular process hyperplasia and degenerative joint disease causing vertebral canal stenosis. All dogs presented with progressive paraparesis, proprioceptive ataxia of the pelvic limbs, and neuroanatomical localization of T3‐L3 myelopathy. All dogs underwent magnetic resonance imaging (MRI) of the thoracolumbar spine and had articular process malformations at T13‐L1 (three German Shepherd dogs (GSD) and a Boxer dog) or T12‐T13 (two mixed‐breed dogs). Five cases were managed surgically. Findings provided more detailed imaging descriptions and supported previously published studies indicating that maldevelopment of articular processes and secondary degenerative changes can be a cause of thoracolumbar spinal stenosis and myelopathy in large breed dogs. While uncommon, this condition should be included as a differential diagnosis for large breed dogs presenting with a T3‐L3 myelopathy.
Background: Vertebral malformations are very common in small brachycephalic breeds, such as French bulldogs, English bulldogs, Boston terriers and pugs. In many cases they are considered incidental findings, but in others they can be associated with progressive neurological deficits. Therefore, it is important to identify which cases will need further investigations, as well as how to interpret the results.
Aim of the article: This article reviews the diagnostic approach and treatment options of spinal malformations that affect small brachycephalic breeds.
Domestic dog breeds exhibit remarkable morphological variations that result from centuries of artificial selection and breeding. Identifying the genetic changes that contribute to these variations could provide critical insights into the molecular basis of tissue and organismal morphogenesis. Bulldogs, French Bulldogs and Boston Terriers share many morphological and disease-predisposition traits, including brachycephalic skull morphology, widely set eyes and short stature. Unlike other brachycephalic dogs, these breeds also exhibit vertebral malformations that result in a truncated, kinked tail (screw tail). Whole genome sequencing of 100 dogs from 21 breeds identified 12.4 million bi-allelic variants that met inclusion criteria. Whole Genome Association of these variants with the breed defining phenotype of screw tail was performed using 10 cases and 84 controls and identified a frameshift mutation in the WNT pathway gene DISHEVELLED 2 (DVL2) (Chr5: 32195043_32195044del, p = 4.37 X 10⁻³⁷) as the most strongly associated variant in the canine genome. This DVL2 variant was fixed in Bulldogs and French Bulldogs and had a high allele frequency (0.94) in Boston Terriers. The DVL2 variant segregated with thoracic and caudal vertebral column malformations in a recessive manner with incomplete and variable penetrance for thoracic vertebral malformations between different breeds. Importantly, analogous frameshift mutations in the human DVL1 and DVL3 genes cause Robinow syndrome, a congenital disorder characterized by similar craniofacial, limb and vertebral malformations. Analysis of the canine DVL2 variant protein showed that its ability to undergo WNT-induced phosphorylation is reduced, suggesting that altered WNT signaling may contribute to the Robinow-like syndrome in the screwtail breeds.
Congenital vertebral malformations (CVM) are common in brachycephalic ‘screw-tailed’ dogs; they can be associated with neurological deficits and a genetic predisposition has been suggested. The purpose of this study was to evaluate radiography as a screening method for congenital thoracic vertebral malformations in brachycephalic ‘screw-tailed’ dogs by comparing it with CT. Forty-nine dogs that had both radiographic and CT evaluations of the thoracic vertebral column were included. Three observers retrospectively reviewed the images independently to detect CVMs. When identified, they were classified according to a previously published radiographic classification scheme. A CT consensus was then reached. All observers identified significantly more affected vertebrae when evaluating orthogonal radiographic views compared with lateral views alone; and more affected vertebrae with the CT consensus compared with orthogonal radiographic views. Given the high number of CVMs per dog, the number of dogs classified as being CVM free was not significantly different between CT and radiography. Significantly more midline closure defects were also identified with CT compared with radiography. Malformations classified as symmetrical or ventral hypoplasias on radiography were frequently classified as ventral and medial aplasias on CT images. Our results support that CT is better than radiography for the classification of CVMs and this will be important when further evidence of which are the most clinically relevant CVMs is identified. These findings are of particular importance for designing screening schemes of CVMs that could help selective breeding programmes based on phenotype and future studies.
Background
Although thoracic vertebral malformations with kyphosis and scoliosis are often considered incidental findings on diagnostic imaging studies of screw-tailed brachycephalic breeds, they have been suggested to interfere with spinal biomechanics and intervertebral disc degeneration. It is however unknown if an abnormal spinal curvature also predisposes dogs to develop clinically relevant intervertebral disc herniations. The aim of this study was to evaluate if the occurrence of thoracic vertebral malformations, kyphosis or scoliosis would be associated with a higher prevalence of cervical or thoracolumbar intervertebral disc extrusion in French bulldogs. ResultsFrench bulldogs that underwent computed tomography for reasons unrelated to spinal disease (n = 101), and French bulldogs with thoracolumbar (n = 47) or cervical intervertebral disc extrusion (n = 30) that underwent magnetic resonance imaging were included. There was a significant association between the presence of kyphosis and the occurrence of intervertebral disc extrusion, particularly in the thoracolumbar region. Dogs with kyphosis were at nearly a two times increased odds of being affected by intervertebral disc extrusion than those without kyphosis [(OR = 1.98 (95% CI: 1.04–3.78)]. There was also an association between the presence of scoliosis and the anatomical distribution of intervertebral disc extrusions, with dogs with scoliosis more likely to have more caudal lumbar intervertebral disc extrusions. Presence of scoliosis was not associated with an increased odds of being affected by intervertebral disc extrusion. Conclusions
Although thoracic vertebral malformations with kyphosis only rarely cause spinal cord dysfunction in itself, French bulldogs with kyphosis appear to be at higher risk to develop thoracolumbar intervertebral disc extrusion.
The widespread occurrence of various malformations of coccygeal vertebrae in dogs has become evident since the ban on tail docking in Switzerland, and has lead to a call for new breeding recommendations. Published reports on examination procedures that may be useful to differentiate causes of tail malformations are scarce. Moreover, there is no classification of these malformations, which could serve as a basis for their assessment and on which breeding recommendations could be made. Material and methods In the present study, coccygeal vertebral malformations are classified based on pathomorphological changes. This classification scheme may be used to standardize the evaluation of malformations by veterinary practitioners and consultants. Results and conclusion Tail malformations were classified based on the evaluation of radiographs of 439 Hovawarts, as well as several dogs of other breeds that were radiographed because of palpable changes of the coccygeal vertebrae. Malformations were grouped according to their presumed pathogenesis. The major aspects of the embryological development of the coccyx are reviewed in preface to facilitate understanding of the various aspects of abnormal development in this region. The different types of malformations are illustrated with radiographs and photomicrographs of histological sections.
To compare data for French Bulldogs and Dachshunds that had hemilaminectomy for thoracolumbar intervertebral disc extrusion (T-L IVDE) by 1 surgeon and to evaluate the association between IVDE and congenital vertebral anomalies.
Retrospective case series.
French Bulldogs (n = 47) and 671 Dachshunds.
Age, gender, vertebral anomaly, kyphosis/kyphoscoliosis, IVDE site, non-recovery and progressive hemorrhagic myelomalacia development from grade 5 (paraplegia without deep nociception) were compared between the 2 breeds.
French Bulldogs were significantly younger (P = .00001), more likely to be male (P = .023), and more likely to have a congenital vertebral anomaly and kyphosis/kyphoscoliosis (P < .00001) than Dachshunds. The frequencies of French Bulldogs with IVDE within typical sites (T11-L3) were significantly lower (P = .0005) and within caudal sites (L3-L7) significantly higher (P = .0001) compared with Dachshunds. None of the French Bulldogs had IVDE within the kyphotic/kyphoscoliotic segment. The frequency of lumbar IVDE (L1-L5) in French Bulldogs with kyphosis/kyphoscoliosis was significantly higher (P = .003) compared with French Bulldogs without kyphosis/kyphoscoliosis. In grade 5 dogs, the risk of developing progressive hemorrhagic myelomalacia in French Bulldogs was significantly higher (P = .03) than in Dachshunds.
The distribution of IVDE site in French Bulldogs within the thoracolumbar and lumbar spine was different from Dachshunds. IVDE sites were not located at the sites of vertebral anomaly. French Bulldogs appeared to have T-L IVDE at younger ages, with higher male predisposition and higher risk of developing progressive hemorrhagic myelomalacia from grade 5 compared with Dachshunds.
Lumbosacral transitional vertebra (LTV) is a common congenital and hereditary anomaly in many dog breeds. It predisposes to premature degeneration of the lumbosacral junction, and is a frequent cause of cauda equina syndrome, especially in German shepherd dogs. Ventrodorsal hip radiographs are most often used in diagnosis of LTV in screening programs. In this study, value of laterolateral lumbar spine radiographs as additions to ventrodorsal radiographs in diagnosis of LTV, and characteristics of LTV and the eighth lumbar vertebra (L8) in laterolateral radiographs were studied. Additionally, computed tomography (CT) features of different types of LTV were elucidated.
The ventrodorsal pelvic and laterolateral lumbar spine radiographs of 228 German shepherd dogs were evaluated for existence and type of LTV. Morphology of transverse processes was used in classification of LTV in ventrodorsal radiographs. The relative length of sixth (L6) and seventh (L7) vertebrae (L6/L7) was used in characterization of these vertebrae in laterolateral radiographs. CT studies were available for 16 dogs, and they were used for more detailed characterization of different types of LTV. Non-parametric χ2 statistics, generalized logit model for multinomial data, and one-way analysis of variance was used for statistical analyses.
In all, 92 (40%) dogs had a LTV, the most common type being separation of first spinous process from the median crest of the sacrum in 62 dogs (67% of LTV). Eight dogs had eight lumbar vertebrae. Those dogs with LTV had longer L7 in relation to L6 than dogs with normal lumbosacral junctions. When L6/L7 decreased by 0.1 units, the proportion of dogs belonging to the group with L8 was 14-fold higher than in the group with normal lumbosacral junctions. L8 resembled first sacral vertebra (S1) in length and position and was therefore classified as one type of LTV. With CT it was shown that categorizing LTV, based on shape and visibility of transverse processes seen in ventrodorsal radiographs, could be misleading.
We suggest that L8 be included as a part of the LTV complex, and the laterolateral radiographs of the lumbar spine be considered as an addition to ventrodorsal projections in the screening protocols for LTV.
This paper reviews 50 years of progress towards understanding the aetiology and pathogenesis of neural tube defects (NTD) in the curly tail (ct) mutant mouse. More than 45 papers have been published on various aspects of curly tail with the result that it is now the best understood mouse model of NTD pathogenesis. The failure of closure of the spinal neural tube, which leads to spina bifida in this mouse, has been traced back to a tissue-specific defect of cell proliferation in the tail bud of the E9.5 embryo. This cell proliferation defect results in a growth imbalance in the caudal region that generates ventral curvature of the body axis. Neurulation movements are opposed, leading to delayed neuropore closure and spina bifida, or tail defects. It is interesting to reflect that these advances have been achieved in the absence of information on the nature of the ct gene product, which remains unidentified. In addition to the principal ct gene, which maps to distal Chromosome 4, the curly tail phenotype is influenced by several modifier genes and by environmental factors. NTD in curly tail are resistant to folic acid, as is thought to be the case in 30% of human NTD, whereas they can be prevented by myo-inositol. These and other features of NTD in this system bear striking similarities to the situation in humans, making curly tail a model for understanding a sub-type folic acid-resistant human NTD.
To compare morphologic and morphometric features of the cervical vertebral column and spinal cord of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy (CSM; wobbler syndrome) detected via magnetic resonance imaging (MRI).
16 clinically normal and 16 CSM-affected Doberman Pinschers.
For each dog, MRI of the cervical vertebral column (in neutral and traction positions) was performed. Morphologically, MRI abnormalities were classified according to a spinal cord compression scale. Foraminal stenosis and intervertebral disk degeneration and protrusion were also recorded. Morphometric measurements of the vertebral canal and spinal cord were obtained in sagittal and transverse MRI planes.
4 of 16 clinically normal and 15 of 16 CSM-affected dogs had spinal cord compression. Twelve clinically normal and all CSM-affected dogs had disk degeneration. Foraminal stenosis was detected in 11 clinically normal and 14 CSM-affected dogs. Vertebral canal and spinal cord areas were consistently smaller in CSM-affected dogs, compared with clinically normal dogs. In neutral and traction positions, the intervertebral disks of CSM-affected dogs were wider than those of clinically normal dogs but the amount of disk distraction was similar between groups.
The incidence of intervertebral disk degeneration and foraminal stenosis in clinically normal Doberman Pinschers was high; cervical spinal cord compression may be present without concurrent clinical signs. A combination of static factors (ie, a relatively stenotic vertebral canal and wider intervertebral disks) distinguished CSM-affected dogs from clinically normal dogs and appears to be a key feature in the pathogenesis of CSM.
Zusammenfassung
Ziel der vorliegenden Arbeit war, die Häufigkeit verschiedener Formen lumbosakraler Übergangswirbel (LÜW) beim Deutschen Schäferhund (DSH) festzustellen. Es sollte überprüft werden, ob eine genetische Basis vorliegt, und eine Einschätzung der Heritabilität (h2) erfolgen. Zusätzlich sollte der Einfluss von LÜW auf die Entstehung von Hüftgelenksdysplasie (HD) bestimmt werden. Material und Methoden: An Röntgenbildern von 4386 DSH mit Abstammungsnachweis wurde die Häufigkeit von LÜW insgesamt sowie bestimmter Formen ermittelt. Es erfolgte eine Heritabilitätsschätzung für das Merkmal LÜW. Neben der Erfassung des offiziellen HD-Befunds nach Fédération Cynologique Internationale (FCI) fand eine HD-Beur teilung nach dem Züricher Punkteschema statt, um Unterschiede zwischen rechtem und linkem Hüftgelenk zu ermitteln. Vorliegen und Formen von LÜW wurden in Korrelation zum HD-Befund gebracht. Ergebnisse: Der festgestellte Anteil an LÜW (29,0%) lag höher als bisher in der Literatur angegeben. Den Großteil der LÜW (78%) bildete die Form mit ausschließlich isoliertem Proc. spinosus am ersten Kreuzbeinwirbel. Unter den ausgeprägteren Formen waren symmetrische (12%) und asymmetrische (10%) LÜW etwa gleich häufig vertreten. Das Geschlecht hatte keinen Einfluss auf das Auftreten eines LÜW. Die Heritabilität lag bei 20–30%. Das Vorliegen eines LÜW stellte keine Prädisposition für HD dar. Schlussfolgerungen und klini sche Relevanz: Die ermittelte Heritabilität für LÜW ermöglicht zuchthygienische Maßnahmen zur Reduzierung von LÜW beim DSH, was im Hinblick auf eine mögliche Korrelation zwischen LÜW und Cauda-equina-Syndrom von Bedeutung sein könnte. Ein Zusammenhang zwischen LÜW und HD war nicht sicher nachweisbar.
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.
The aims of this study were to evaluate the prevalence and anatomical characteristics of thoracic caudal articular process dysplasia in French bulldogs, English bulldogs and Pugs presenting for problems unrelated to spinal disease. In this retrospective cross-sectional study, computed tomography scans of the thoracic vertebral column of these three breeds were reviewed for the presence and location of caudal articular process hypoplasia and aplasia, and compared between breeds. A total of 271 dogs met the inclusion criteria: 108 French bulldogs, 63 English bulldogs, and 100 Pugs. A total of 70.4% of French bulldogs, 84.1% of English bulldogs, and 97.0% of Pugs showed evidence of caudal articular process dysplasia. Compared to French and English bulldogs, Pugs showed a significantly higher prevalence of caudal articular process aplasia, but also a lower prevalence of caudal articular process hypoplasia, a higher number of affected vertebrae per dog and demonstrated a generalized and bilateral spatial pattern more frequently. Furthermore, Pugs showed a significantly different anatomical distribution of caudal articular process dysplasia along the vertebral column, with a high prevalence of caudal articular process aplasia between T10 and T13. This area was almost completely spared in French and English bulldogs. As previously suggested, caudal articular process dysplasia is a common finding in neurologically normal Pugs but this also seems to apply to French and English bulldogs. The predisposition of clinically relevant caudal articular process dysplasia in Pugs is possibly not only caused by the higher prevalence of caudal articular process dysplasia, but also by breed specific anatomical characteristics.
Congenital vertebral malformations are common incidental findings in small breed dogs. This retrospective observational study evaluated the type and prevalence of thoracic vertebral malformations in 171 neurologically normal and 10 neurologically abnormal screw-tailed brachycephalic dogs. Neurologically normal dogs underwent CT for reasons unrelated to spinal disease, while affected dogs underwent MRI. Imaging studies were reviewed and vertebral malformations including hemivertebrae, block vertebrae, transitional vertebrae, and spina bifida were documented.
The group of clinically normal dogs consisted of 62 French bulldogs, 68 Pugs and 41English bulldogs. The group of affected dogs consisted of one French bulldog and nine Pugs. Overall, 80.7% of neurologically normal animals were affected by at least one vertebral malformation. There was a significant influence of breed, with thoracic vertebral malformations occurring more often in neurologically normal French bulldogs (P<0.0001)and English bulldogs (P=0.002). Compared to other breeds, hemivertebrae occurred more often in neurologically normal French bulldogs (93.5%; P< 0.0001 vs. Pugs; P=0.004 vs. English bulldogs) and less often in neurologically normal Pugs (17.6%; P=0.004 vs. English bulldogs). Neurologically normal Pugs were more often diagnosed with transitional vertebrae and spina bifida compared to other breeds (P<0.0001 for both malformations). Of Pugs included in the study, 4.7% were diagnosed with clinically relevant thoracic vertebral malformations. When compared to the general veterinary hospital population, this was significantly more than the other two breeds (P= 0.006). This study indicates that thoracic vertebral malformations occur commonly in neurologically normal screw-tailed brachycephalic dogs. While hemivertebrae are often interpreted as incidental diagnostic findings, they appear to be of greater clinical importance in Pugs compared to other screw- tailed brachycephalic breeds.
Objective:
Transitional lumbosacral vertebrae (TLSV) is a hereditary malformation of the spinal column diagnosed in various dog breeds. The aim of this study was to explore whether different lumbosacral phenotypes have an inherited basis.
Methods:
Radiographs of all dogs within a breeding colony were performed and assessed. A comparison of the incidence of TLSV, eight lumbar vertebrae (8LV), and fusion of the first caudal vertebrae to the sacrum or near fusion of this area was made between litters of normal parentage and litters where one or both of the parents had an anomaly.
Results:
Of the 119 puppies included in the study, 69 had normal conformation, 9 had 8LV, 9 had TLSV and 32 had fusion of the first caudal vertebra (Ca1) to the caudal sacral segment or a reduced joint space in this area. Results indicated that all the abnormal types likely had common underlying genetic causes. Compared with the population as a whole, significantly more progeny were observed to have abnormalities of the sacral region when both parents were affected by either fusion of Ca1 to the third sacral vertebra (S3) and/or had 8LV. Significantly more progeny were normal compared with the entire study population when both parents were normal. Strong similarity between parental and progeny phenotypes suggested that the characteristics were heritable and likely influenced by major gene effects.
Conclusion:
When performing screening radiographs for TLSV, assessment for 8LV and fusion of Ca1 to S3 should be included.
A prospective study to create radiographic classification of caudal vertebral anomalies in dogs was performed and the prevalence of the disorders estimated. Radiographic examination of the caudal vertebrae was performed in 595 client-owned dogs undergoing routine radiological examination of the hip joints. Anomalies of the caudal vertebrae were divided into four groups: (1) congenital anomalies with aberrant fusion of the vertebral epiphysis, like hemivertebra, block or transitional vertebra; (2) morphological anomalies like vertebra curva and dysplastic vertebral epiphysis; (3) post-traumatic changes, represented by fracture or luxation; and (4) degenerative changes, represented by spondylosis, osteophyte formation and mineralisation of intervertebral spaces. A total of 303 caudal vertebral anomalies were detected in 259 dogs (43.53% of all dogs examined). A single type of vertebral anomaly was present in 215 dogs and a combination of two pathologies was recorded in 44 dogs, which represents 83.01% and 16.99%, respectively, of the affected dogs. Congenital anomaly was present in 11.09% of the dogs examined. Sacrocaudal transitional vertebra was the most common congenital anomaly, present in 12.74% of the affected dogs. Radiographic examination of the caudal vertebrae is recommended as an essential part of any screening process to confirm the presence of congenital anomaly as a cause of kinked tail.
Ordinal regression and animal threshold analyses were used to estimate the influence of fixed effects and heritabilities on the number and grade of hemivertebrae, as well as the number of coccygeal vertebrae, in 105 French bulldogs. The fixed effects of sex, year and month of birth were not significant (P > 0.05). The prevalence of hemivertebrae was 0.85 with a slightly higher prevalence in females compared with males. Heritability estimates for the number and grade of hemivertebrae were 0.58 and 0.53, respectively. The number of coccygeal vertebrae showed a heritability estimate of 0.35. In addition, the number of coccygeal vertebrae was negatively correlated with the number and grade of hemivertebrae. The prevalence of hemivertebrae could increase if dogs with shorter tails are preferentially selected for breeding purposes.
Objective:
To compare clinical signs of dogs treated medically or surgically for degenerative lumbosacral stenosis (DLSS) and assess outcome after medical treatment.
Design:
Retrospective case series.
Animals:
Client-owned dogs treated medically (n = 49) or surgically (49) for DLSS.
Procedures:
Medical records from 2004 to 2012 were reviewed. Dogs were included if they had clinical signs, clinical examination findings, and MRI abnormalities consistent with DLSS. Several variables were compared between surgically and medically treated dogs: age, sex, duration of clinical signs, presence or absence of neurologic deficits, urinary and fecal incontinence, concurrent medical conditions, and medical treatment before referral. Medical treatment after obtaining a final diagnosis of DLSS consisted of restricted exercise in combination with anti-inflammatory and analgesic drugs. Surgical treatment consisted of dorsal lumbosacral laminectomy. Outcome for medically treated dogs was obtained via a standardized questionnaire.
Results:
Neurologic deficits were observed significantly more often in surgically treated dogs. Surgically treated dogs had unsuccessful medical treatment before referral significantly more often than did medically treated dogs. Thirty-one of 49 (63.3%) medically treated dogs were available for follow-up evaluation. Of these 31 dogs, 17 (55%) were managed successfully, 10 (32.3%) were managed unsuccessfully and underwent surgical treatment, 3 (9.7%) were euthanized because of progression of clinical signs, and 1 (3.2%) was alive but had an increase in severity of clinical signs after medical management.
Conclusions and clinical relevance:
Clinical signs differed in dogs treated medically or surgically for DLSS. Medical treatment for dogs with DLSS was associated with a fair prognosis.
Congenital vertebral malformations are common in brachycephalic “screw-tailed” dog breeds such as French bulldogs, English bulldogs, Boston terriers, and pugs. The aim of this retrospective study was to determine whether a radiographic classification scheme developed for use in humans would be feasible for use in these dog breeds. Inclusion criteria were hospital admission between September 2009 and April 2013, neurologic examination findings available, diagnostic quality lateral and ventro-dorsal digital radiographs of the thoracic vertebral column, and at least one congenital vertebral malformation. Radiographs were retrieved and interpreted by two observers who were unaware of neurologic status. Vertebral malformations were classified based on a classification scheme modified from a previous human study and a consensus of both observers. Twenty-eight dogs met inclusion criteria (12 with neurologic deficits, 16 with no neurologic deficits). Congenital vertebral malformations affected 85/362 (23.5%) of thoracic vertebrae. Vertebral body formation defects were the most common (butterfly vertebrae 6.6%, ventral wedge-shaped vertebrae 5.5%, dorsal hemivertebrae 0.8%, and dorso-lateral hemivertebrae 0.5%). No lateral hemivertebrae or lateral wedge-shaped vertebrae were identified. The T7 vertebra was the most commonly affected (11/28 dogs), followed by T8 (8/28 dogs) and T12 (8/28 dogs). The number and type of vertebral malformations differed between groups (P = 0.01). Based on MRI, dorsal, and dorso-lateral hemivertebrae were the cause of spinal cord compression in 5/12 (41.6%) of dogs with neurologic deficits. Findings indicated that a modified human radiographic classification system of vertebral malformations is feasible for use in future studies of brachycephalic “screw-tailed” dogs.
In people, abnormalities in vertebral column conformation, such as kyphoscoliosis, induce degenerative changes in adjacent intervertebral disc (IVD) structure and composition. It was hypothesised that canine IVDs adjacent to a vertebral malformation undergo early degeneration.
In a blinded retrospective study, thoracic IVD degeneration was evaluated in 14 dogs on magnetic resonance images using Pfirrmann’s grade. IVDs adjacent to a vertebral malformation had higher grades of degeneration than non-adjacent IVDs (P<0.0001). There was an age-dependency, with dogs between 1 and 4 years showing higher grade of degeneration in adjacent than non-adjacent IVDs (P<0.0001). Conversely, in older dogs, all IVDs - including the non-adjacents - showed degenerative signs, possibly due to normal aging. These results suggest that congenital vertebral malformation results in early degeneration of adjacent IVDs.
Objective:
To describe diagnostic findings, surgical technique, and outcome in dogs with thoracic spinal canal stenosis and vertebral instability secondary to congenital vertebral anomalies.
Study design:
Retrospective clinical study.
Animals:
Dogs (n=9) with thoracic spinal canal stenosis.
Methods:
Medical records (1995-1996; 2000-2006) of 9 dogs with a myelographic diagnosis of spinal canal stenosis and/or vertebral instability secondary to congenital vertebral anomaly that were surgically managed by vertebral stabilization with or without laminectomy were reviewed. Data on pre- and postoperative neurologic status, diagnostic findings, surgical techniques, and outcomes were retrieved. Follow-up evaluations were performed at 1, 2, and 6 months. Long-term outcome was assessed by means of clinical examination or owner telephone interviews.
Results:
Spinal cord compression was confirmed by myelography, and in 2 dogs, dynamic compression by stress myelography. Eight dogs regained the ability to ambulate postoperatively. One dog with a partial recovery regained voluntary movement but did not become ambulatory.
Conclusions:
Spinal cord injury secondary to congenital vertebral anomaly may have a good outcome when treated by vertebral stabilization with or without laminectomy. Adequate stabilization of the vertebrae and improved neurologic outcome were achieved in most dogs.
Clinical relevance:
Vertebral stabilization using positively threaded profile pins and polymethylmethacrylate with or without laminectomy is an effective treatment for spinal canal stenosis and vertebral instability secondary to congenital thoracic vertebral anomalies.
To radiographically assess the influence of thoracic hemivertebra on kyphosis and neurologic status in 45 dogs.
Case series.
French Bulldogs without neurologic signs (n = 41) and 4 dogs with compressive spinal cord disease associated with hemivertebra.
Thoracic spinal radiographs were divided into 3 groups: 1 = dogs with no hemivertebra, 2 = dogs with hemivertebra but no associated neurologic signs, and 3 = dogs with hemivertebra associated with clinical signs. Vertebral canal height, vertebral column angle, and the step between 2 adjacent vertebrae were measured in each group.
Vertebral canal height was not significantly different in the 3 groups; however, mean vertebral column angle was significantly (P < .001) different between groups 1 (178°) and 2 (169°), and group 3 (133°). Median cranial step was significantly different between groups (P < .001): 0 mm (group 1), 0.3 mm (group 2), 3 mm (group 3).
Vertebral canal height does not differ between normal dogs and dogs with thoracic hemivertebra. There is an important association between neurologic signs and kyphosis and subluxation.
Vertebral realignment without vertebral canal opening could lead to spinal cord decompression in dogs affected by thoracic hemivertebra.
Congenital anomalies of the spine are common in small animals. The type of deformity, location, severity, time of onset of associated clinical signs, and progression of neurologic dysfunction varies widely. To promote clearer understanding, the authors present the various spinal malformations using modified human classification schemes and use current widely accepted definitions and terminology. The diagnostic approach, including utilization of advanced imaging, and surgical management is emphasized.
This report describes a partial ventral verte-brectomy and interbody fusion for a progressive hemivertebra disease using a ventral transthoracic approach in a 3.6-month-old male Labrador puppy. The goal of this article is to clarify the potential advantages of this uncommon surgical technique for this condition and to discuss its technical aspects.
Objective-To determine the spectrum and frequency of abnormalities for low-field magnetic resonance imaging (MRI) examinations of clinically normal Doberman Pinschers and Foxhounds.
Animals-37 clinically normal dogs (20 Doberman Pinschers and 17 Foxhounds).
Procedures-For each dog, MRI of the cervical vertebrae (sagittal, dorsal, and transverse T1- and T2-weighted images) was performed. Variables assessed were intervertebral disk degeneration, disk-associated compression, compression of the dorsal portion of the spinal cord, vertebral body abnormalities, and changes in intraparenchymal signal intensity. Associations between these variables and age, breed, sex, and location of the assessed intervertebral disk spaces were evaluated.
Results-Severe MRI abnormalities were detected in 17 dogs, including complete disk degeneration (n = 4 dogs), spinal cord compression (3), or both (10). Vertebral body abnormalities were detected in 8 dogs, and hyperintense signal intensity was detected in 2 dogs. Severity of disk degeneration and disk-associated compression was significantly associated with increased age. There was a significant association between disk degeneration, disk-associated compression, and compression of the dorsal aspect of the spinal cord and location of the assessed intervertebral disk space, with the intervertebral disk spaces in the caudal portion of the cervical region being more severely affected.
Conclusions and Clinical Relevance-Abnormalities were commonly seen on MRI examinations of the caudal portion of the cervical vertebral column and spinal cord of clinically normal Doberman Pinchers and Foxhounds. Such lesions were probably part of the typical spinal cord degeneration associated with the aging process of dogs. (Am J Vet Res 2010;71:428-434)
Diss. med. vet. Bern (kein Austausch).
A cross-sectional population study of magnetic resonance imaging (MRI) changes. OBJECTIVE.: To examine the pattern and prevalence of lumbar spine MRI changes within a southern Chinese population and their relationship with back pain.
Previous studies on MRI changes and back pain have used populations of asymptomatic individuals or patients presenting with back pain and sciatica. Thus, the prevalence and pattern of intervertebral disc degeneration within the population is not known.
Lumbar spine MRIs were obtained in 1043 volunteers between 18 to 55 years of age. MRI changes including disc degeneration, herniation, anular tears (HIZ), and Schmorl's nodes were noted by 2 independent observers. Differences were settled by consensus. Disc degeneration was graded using Schneiderman's classification, and a total score (DDD score) was calculated by the summation of the Schneiderman's score for each lumbar level. A K-mean clustering program was used to group individuals into different patterns of degeneration.
Forty percent of individuals under 30 years of age had lumbar intervertebral disc degeneration (LDD), the prevalence of LDD increasing progressively to over 90% by 50 to 55 years of age. There was a positive correlation between the DDD score and low back pain. L5-S1 and L4-L5 were the most commonly affected levels. Apart from the usual patterns of degeneration, some uncommon patterns of degeneration were identified, comprising of subjects with skip level lesions (intervening normal levels) and isolated upper or mid lumbar degeneration.
LDD is common, and its incidence increases with age. In a population setting, there is a significant association of LDD on MRI with back pain.
Spina bifida was diagnosed in four English Bulldogs and one Collie dog. These cases and the examination of records from the Veterinary Medical Data Program suggested a high incidence of spina bifida in the English Bulldog. Urinary and fecal incontinence was the most common reason for initial examination for the five dogs. Radiographs and myelography confirmed the diagnosis of spina bifida. Blood, cerebrospinal fluid and urine analyses did not aid diagnosis but urocystitis was identified. In addition to spina bifida, clinical signs and morphologic changes in the spinal cords of all five dogs fulfilled the criteria for an additional diagnosis of spinal dysraphism. A common pathogenesis for the two conditions is suggested.
The clinical and radiographic findings associated with the presence of hemivertebra ("wedge-shaped"vertebra) in small and brachycephalic breeds of dogs are reported together with the results of post mortem examination in the availabel cases. The condition is characterised clinically by progressive hind-leg weakness, spinal pain, abnormalities of the nervous system and evidence of muscle atrophy or other abnormalities of conformation. Confirmation of the clinical diagnosis is by radiography. It is suggested that the condition is congenital in origin. Breed incidences are reported. The occurrence of the disorder in certain families of dogs suggests also that it may be hereditary. Other congenital abnormalities are seen in some dogs affected by hemivertebrae.
A 3-month-old English Bulldog had excretory incontinence and sensory deficits in the distribution of pudendal nerves. Noncontrast radiography, myelography, and computed tomography revealed spina bifida beginning at L7, an expanded subarachnoid space caudal to L7, and a taut, thick filum terminale. Microsurgical exploration of the lumbosacral spine confirmed the presence of a tethered cord, and the filum terminale was transected. The spinal cord immediately migrated cranially about 1 cm. Although some sensory improvement was evident during a 2-week postoperative period, the dog was euthanatized. Postmortem examination confirmed spina bifida and atrophy of sacral nerve roots and perineal muscles, thoracic hemivertebrae, and hydrocephalus.
An 8-month-old English Bulldog with focal and urinary incontinence was examined before and after death. There was nonfusion of the dorsal laminae of vertebra L, in the midline. Through this defect a small meningomyelocoele, and the terminal part of the spinal cord, emerged from the spinal canal. The clinical signs were attributed to damage of both pudendal nerves or their spinal cold segments. The dog had normal spinal cord function to all limbs.
This study presents the estimates of heritability for spondylosis deformans in the boxer based on 353 offspring from 24 randomly selected sires, each with at least three radiographically investigated offspring. The estimated heritability (h2) for maximum degree of osteophyte development was high, both when estimated by paternal half-sib correlation (0.42) and by the regression of offspring based on the parents (0.62). The heritability for the number of affected discs estimated by paternal half-sib correlation was also high (0.47). The estimate of heritability for the number of affected discs based on regression of offspring on the parents was lower at 0.13. All heritabilities had large standard errors. A positive phenotypic correlation between spondylosis deformans and hip dysplasia was observed. Assuming a significant portion of the correlation is genetic, this fact may permit selection against spondylosis deformans without negatively influencing the incidence of hip dysplasia. Since the incidence of spondylosis deformans is high even in young dogs, it should be possible to detect a large proportion of genetically predisposed animals by radiographic examination of the spine at one year of age; at the same time that dogs are presented for a routine test for hip dysplasia.
Computed tomography (CT) of the L5-S3 vertebral levels was performed in six, large-breed dogs presented for problems unrelated to the lumbosacral spine. All dogs were asymptomatic for lumbosacral stenosis on neurologic examination. Breeds included German Shepherd, Golden Retriever, Boxermix and Belgian Malinois. Ages ranged from 5-12 years. Five out of six dogs exhibited CT abnormalities. Among the 18 disc levels examined, the most common findings were idiopathic stenosis, loss of vertebral canal epidural fat, and nerve tissue displacement. Less common abnormalities were vertebral canal or foraminal bone proliferation, loss of intervertebral foramen fat, vertebral canal disc bulging, degenerative articular process joint disease, transitional vertebra, dural ossification, foraminal disc bulging, Schmorl's nodes, calcified extruded disc fragment, and sacroiliac joint osteophytes. Vertebral subluxation was absent in all dogs. Findings indicate that some lumbosacral CT abnormalities may be clinically insignificant, especially in older dogs.
Neural tube defects (NTDs), including spina bifida and anencephaly, are common congenital malformations that occur when the neural tube fails to achieve proper closure during early embryogenesis. Based on epidemiological and clinical data obtained over the last few decades, it is apparent that these multifactorial defects have a significant genetic component to their etiology that interacts with specific environmental risk factors. The purpose of this review article is to synthesize the existing literature on the genetic factors contributing to NTD risk.
To date, there is evidence that closure of the mammalian neural tube initiates and fuses intermittently at four discrete locations. Disruption of this process at any of these four sites may lead to an NTD, possibly arising through closure site-specific genetic mechanisms. Candidate genes involved in neural tube closure include genes of the folate metabolic pathway, as well as those involved in folate transport.
Although extensive efforts have focused on elucidating the genetic risk factors contributing to the etiology of NTDs, the population burden for these malformations remains unknown. One group at high risk for having children with NTDs is epileptic women receiving antiepileptic medications during pregnancy. Efforts to better understand the genetic factors that may contribute to their heightened risk, as well as the pathogenesis of neural tube closure defects, are reviewed herein.
The association between the occurrence of a lumbosacral transitional vertebra (LTV) and the cauda equina syndrome (CES) in dogs was investigated. In 4000 control dogs without signs of CES, 3.5% had an LTV, while in 92 dogs with CES, 16.3% had an LTV. The lesion causing CES always occurred between the last true lumbar vertebra and the LTV. Dogs with an LTV were eight times more likely to develop CES than dogs without an LTV. German Shepherd dogs were eight times more likely to develop CES compared with other breeds. Male dogs were twice as likely to develop CES than females. Dogs with an LTV develop CES 1-2 years earlier than dogs without an LTV.
The prevalence of lumbosacral transitional vertebrae (LTV) was determined by reviewing the pelvic radiographs of 4000 medium- and large-breed dogs of 144 breeds routinely screened for canine hip dysplasia. An LTV was seen in 138 (3.5%) dogs. The prevalence was higher in German Shepherd dogs and Greater Swiss Mountain dogs than in the other breeds, suggesting a genetic predisposition. There was no gender predisposition. The transverse processes of the LTV were divided into three types based on their morphological characteristics: lumbar type or type 1; intermediate type or type 2; and sacral type or type 3. In a symmetric LTV, both transverse processes are of the same type, while in an asymmetric LTV they are not. The frequency of occurrence of symmetric and asymmetric LTV was similar. In symmetric LTV, intermediate-type transverse processes predominated. Most of the asymmetric LTV had an intermediate-type transverse process combined with a lumbar or sacral type, respectively. Highly asymmetric LTV were often angled relative to the adjacent vertebrae. We hypothesize that an LTV is not the result of transformation of a lumbar into a sacral vertebra or vice versa, but rather is an autonomous intermediate type of vertebra. It occurs when the point of contact of the pelvis with the vertebral column is slightly cranial or caudal to its normal position. The resulting formative stimulus on the vertebral ossification centers, sagittally still separated, causes the various morphologies seen in LTV including the asymmetric variations.
3 immature screw-tailed dogs were evaluated because of progressive pelvic limb paraparesis.
Each dog had marked ataxia and paresis of the pelvic limbs and a palpable deformity of the midthoracic portion of the vertebral column. Pain perception in the pelvic limbs was considered normal, and there was no evidence of fecal or urinary incontinence in any of the 3 dogs. Radiography and magnetic resonance imaging revealed hemivertebrae with severe dorsoventral stenosis of the vertebral canal resulting in spinal cord compression in 2 dogs and lateral compression in the other.
Each dog underwent decompressive surgery consisting of dorsal laminectomy or hemilaminectomy and vertebral stabilization by use of combinations of Kirschner wires or threaded external fixator pins plus polymethylmethacrylate bone cement. All dogs regained strong locomotor function with minimal residual pelvic limb ataxia.
Little detailed information regarding surgical treatment of hemivertebrae in dogs is available; results of treatment in these 3 dogs suggest that spinal cord decompression and stabilization of the vertebral column can achieve a satisfactory, functional outcome.
Vertebral stabilization using positively threaded profile pins and polymethylmethacrylate, with or without laminectomy, for spinal canal stenosis and vertebral instability caused by congenital thoracic vertebral anomalies
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Low‐field magnetic resonance imaging findings of the caudal portion of the cervical region in clinically normal Doberman Pinschers and Foxhounds
- Decker S