Randomized single-blinded prospective comparison between ozone therapy and electroacupuncture for canine thoracolumbar disk disease.

Ozone therapy has been used to control pain in animals. Moreover, electroacupuncture (EA) has been effective in neurological recovery and pain control in dogs with thoracolumbar discopathy. EA was compared with Ozone applied at acupuncture points in dogs with signs of thoracolumbar disk disease. Chondrodystrophic mongrel dogs, with lesion scores between 1 and 4, were randomly divided into groups: EA (n = 13) - electroacupuncture at BL20, BL23, ST36, KID3 and BL60 and dry needle in lumbar Bai Hui, and OZO (n = 15) - paravertebral application of 3 mL ozone (20 µg / mL) at BL20, BL23, lumbar Bai Hui, ST36, and KID3/BL60, both groups with weekly applications. No significant differences were observed between groups in weekly blind pain assessments using a dynamic interactive visual analog scale, and neurological assessments using a numerical-functional scale. Both groups showed a progressive improvement in pain control and neurological condition, which was observed when comparing the group's EA and OZO in dogs with all lesion scores. The time of return to locomotion (days) of dogs scored 3 and 4, between groups EA (10.6 ± 5.4) and OZO (14.5 ± 15.7), had no significant differences. Ozone therapy was effective to control pain and motor rehabilitation and sensory functions of dogs with thoracolumbar discopathy signs, just as electroacupuncture. Ozone application was a quick and easy-to-handle treatment. Paravertebral and subcutaneous routes did not require anesthesia or other advanced imaging technology, besides being safe and effective.

Lumbosacral endplate contour defect is frequently observed concurrent with other lumbosacral abnormalities on spinal CT of French Bulldogs.

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.

The spinal cord-to-vertebral canal area ratio measured with computed tomography is lower in the thoracolumbar than the cervical region in French Bulldogs.

OBJECTIVE: To compare spinal cord-to-vertebral canal area ratios measured with CT between the cervical and thoracolumbar regions in French Bulldogs. ANIMALS: 37 French Bulldogs presented to a referral hospital between 2016 and 2019. PROCEDURES: The study was conducted as a retrospective observational study. Exclusion criteria were evidence of vertebral malformations or spinal cord compression at the sites where measurements were obtained and the presence of cervicothoracic or thoracolumbar transitional vertebrae or neurologic deficits. CT images were reviewed, and measurements were performed by 2 investigators. Measurements of the spinal cord and vertebral canal were made at the level of or immediately cranial to the midbodies of C5 and L1. RESULTS: A 2-tailed, paired t test indicated that the mean spinal cord-to-vertebral canal area ratio differed significantly (P < .01) between C5 (0.726) and L1 (0.605). The ratio was lower in the thoracolumbar region, suggesting that the vertebral canal was relatively larger in this region. CLINICAL RELEVANCE: The epidural space did not appear to be larger in the cervical than in the thoracolumbar region in this population of French Bulldogs, contrary to previous reports. The reason for the more severe deficits observed with thoracolumbar disk extrusion in this breed remains to be characterized.

Evaluation of Paraspinal Musculature in Small Breed Dogs with and without Atlantoaxial Instability Using Computed Tomography.

OBJECTIVE: The aim of this study was to evaluate differences in paraspinal musculature between dogs with and without atlantoaxial instability (AAI) using computed tomography scans. STUDY DESIGN: Retrospective multicentre study evaluating transverse reconstructed computed tomography scans of 83 small breed dogs (34 with and 49 without AAI) for the cross-sectional paraspinal musculature area at three levels (Occiput/C1, mid-C1, mid-C2). Ratio of moments, dorsal-to-ventral muscle-area ratios (d-v-ratio) and ratios of the dorsal and ventral musculature to C2 height (d-C2-ratio and v-C2-ratio) were evaluated for differences between groups using multivariate analysis of variance (p < 0.05) taking the head-neck position into account. RESULTS: Dogs with AAI showed a significantly lower d-v-ratio at levels 2 and 3, d-C2-ratio at level 2 and ratio of moments at all levels. When head-neck positions were analysed separately, ratio of moments was significantly lower in affected dogs at level 1 and 2. Also lower was d-C2-ratio at level 2, but only in flexed positioning. The head-neck position had a significant influence on ratio of moments and d-v-ratio at all three levels and on d-C2-ratio at level 1. CONCLUSION: Significant changes in muscle area were observed only for the hypaxial muscles at the C1 level, indicating a limited role of muscular adaption in AAI patients. Our results confirm an altered ratio of moments in dogs with AAI. The head-neck position has a significant impact and should be taken into account when evaluating spinal musculature.

Determination of cutoff values on computed tomography and magnetic resonance images for the diagnosis of atlantoaxial instability in small-breed dogs.

OBJECTIVE: To determine cutoff values for the diagnosis of atlantoaxial instability (AAI) based on cross-sectional imaging in small-breed dogs. STUDY DESIGN: Retrospective multicenter study. SAMPLE POPULATION: Client-owned dogs (n = 123) and 28 cadavers. METHODS: Dogs were assigned to three groups: a control group, a "potentially unstable" group, and an AAI-affected group, according to imaging findings and clinical signs. The ventral compression index (VCI), cranial translation ratio (CTR), C1-C2 overlap, C1-C2 angle, atlantoaxial distance, basion-dens interval, dens-to-axis length ratio (DALR), power ratio, and clivus canal angles were measured on CT or T2-weighted magnetic resonance (MR) images. Receiver operating characteristic (ROC) analysis was performed to define cutoff values in flexed (≥25°) and extended (<25°) head positions. RESULTS: Cutoff values for the VCI of ≥0.16 in extended and ≥0.2 in flexed head positions were diagnostic for AAI (sensitivity of 100% and 100%, specificity of 94.54% and 96.67%, respectively). Cutoff values for the other measurements were defined with a lower sensitivity (75%-96%) and specificity (70%-97%). A combination of the measurements did not increase the sensitivity and specificity compared with the VCI as single measurement. CONCLUSION: Cutoff values for several imaging measurements were established with good sensitivity and specificity. The VCI, defined as the ratio between the ventral and dorsal atlantodental interval, had the highest sensitivity and specificity in both head positions. CLINICAL SIGNIFICANCE: The use of defined cutoff values allows an objective diagnosis of AAI in small-breed dogs. The decision for surgical intervention, however, should remain based on a combination of clinical and imaging findings.

Preliminary evaluation of a non-invasive device for monitoring intracranial pressure waveforms in dogs.

OBJECTIVES: The objective of this study was to compare waveforms obtained with a new device for the non-invasive monitoring of intracranial pressure (ICP) in dogs with and without neurological disease. MATERIALS AND METHODS: This prospective study was conducted on both neurologically normal dogs and dogs with neurological diseases. First, non-invasive ICP waveforms were recorded in normal dogs using the Braincare® BcMM 2000 monitor while the dogs were under general anaesthesia induced for procedures unrelated to this study. The dogs were positioned in lateral recumbency, and the sensor was placed over the skin of the parietal region. Secondly, non-invasive ICP waveforms were monitored in dogs with brain and spinal disease until waveforms with characteristic peaks were acquired. All the recorded signals were amplified, filtered and digitalized, by the device, and then transferred to a computer for analysis. RESULTS: Normal pulse waveforms indicating normal brain complacency were observed in eight neurologically normal dogs. In six dogs with brain disease, abnormal pulse waveforms were observed suggesting increased ICP and decreased brain complacency. Four dogs with spinal disease undergoing myelography, had normal waveforms before contrast medium injection and abnormal pulse waveforms during contrast medium injection, indicating a potential increase in ICP. CLINICAL SIGNIFICANCE: Based on these preliminary observations, this method was capable of detecting abnormal pulse waveforms that suggested increased ICP.

Vertebral vascular canal dysplasia in French and English Bulldogs: Clinical, CT, and MRI characteristics and prevalence.

The authors have observed a vertebral anomaly in French and English Bulldogs and termed this anomaly "vertebral vascular canal dysplasia (VVCD)." No previously published descriptions of this anomaly were found. The aims of this retrospective, multi-institutional, observational study were to (1) describe the clinical, CT, and MRI characteristics of VVCD, and (2) estimate the prevalence and describe the characteristics of VVCD in a group of French and English Bulldogs. For descriptions of the anomaly, medical records and imaging studies of nine clinical cases with VVCD from several countries were reviewed. For estimation of prevalence, imaging studies of French and English Bulldogs from the United Kingdom (UK) and Italy were reviewed. All clinical case dogs had ≥5 thoracic vertebrae with VVCD affecting >50% of vertebral body height (VBH). The prevalence of VVCD involving ≥1 thoracic vertebra in the UK population (CT identified) of English Bulldogs and French Bulldogs was, respectively, 83.3% (30/36) and 68.3% (28/41). English Bulldogs had significantly more thoracic vertebrae with VVCD than French Bulldogs (P = < 0.01). The prevalence of VVCD in ≥1 thoracic vertebra in the Italian population (MRI identified) of English Bulldogs and French Bulldogs was, respectively, 21.7% (5/23) and 6.6% (7/106). Vertebral vascular canal dysplasia was observed in normal as well as in malformed vertebrae (e.g., hemivertebrae). Findings from the current study introduced descriptions of VVCD that can be used as background for future studies.

Radiographic evaluation of congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis).

BACKGROUND: The normal vertebral anatomy of Korean raccoon dogs and their variants require research attention as a prerequisite for identifying pathologies and anomalies. OBJECTIVES: This retrospective study aimed at describing the vertebral formula and congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis). METHODS: Radiographs of 82 raccoon dogs (42 males, 40 females) acquired from May 2013 to June 2020 in the Gangwon Wildlife Medical Rescue Center were reviewed to evaluate the cervical, thoracic, and lumbar vertebrae of the spine. RESULTS: Normal morphology of all vertebrae was observed in 50 of the 82 raccoon dogs, and the vertebral formula was cervical 7, thoracic 13, and lumbar 7. Congenital vertebral anomalies were found in 32 raccoon dogs: transitional vertebrae (TV) in 31 and block vertebrae in 2. Two raccoon dogs had 2 types of vertebral anomalies: one had TV and block vertebra, and the other had 2 types of TV. Twenty-nine raccoon dogs had thoracolumbar TV (TTV) and 3 had lumbosacral TV. TTV was morphologically classified into 4 different types: unilateral extra-rib in 5 raccoon dogs, bilateral extra-ribs in 14, bilateral elongated transverse processes in 4, and an asymmetric mixed formation of extra-rib with elongated transverse process in 6. CONCLUSIONS: This study showed that TTV is common in Korean raccoon dogs, and that the vertebral formula is relatively diverse. The bilateral extra-ribs type TTV is the most common variant, which is almost similar to normal rib to be confused the radiographic evaluation.

Kinematics of a Novel Canine Cervical Fusion System.

OBJECTIVE: The aim of this study was to determine the biomechanical behaviour of a novel distraction-fusion system, consisting of an intervertebral distraction screw, pedicle locking screws and connecting rods, in the canine caudal cervical spine. STUDY DESIGN: Biomechanical study in cadaveric canine cervicothoracic (C3-T3) spines (n = 6). Cadaveric spines were harvested, stripped of musculature, mounted on a four-point bending jig, and tested using non-destructive four-point bending loads in extension (0-100 N), flexion (0-60 N) and lateral bending (0-40 N). Angular displacement was recorded from reflective optical trackers rigidly secured to C5, C6 and C7. Data for primary and coupled motions were collected from intact spines and following surgical stabilization (after ventral annulotomy and nucleotomy) with the new implant system. RESULTS: As compared with the intact spine, instrumentation significantly reduced motion at the operated level (C5-C6) with a concomitant non-significant increase at the adjacent level (C6-C7). CONCLUSION: The combination of a locking pedicle screw-rod system and intervertebral spacer provides an alternative solution for surgical distraction-stabilization in the canine caudal cervical spine and supports the feasibility of using this new implant system in the management of disc-associated cervical spondylomyelopathy in dogs. The increase in motion at C6-C7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this.

Quantitative motor unit action potential analysis of paraspinal muscles, diagnostic imaging and necropsy findings in 36 horses suspected of cervical impairment.

INTRODUCTION: Aims: To determine the relation between quantitative electromyography (QEMG) of the cervical ventral serratus muscle, radiographic findings and post-mortem gross and histopathological examination in order to calculate the ability of QEMG to localize the region of cervical compressive neuropathy and myelopathy in horses. Methods: In this clinical, non-randomised, partially blinded study (QEMG and histology), 36 warmblood horses with clinical suspicion of cervical spine disease were examined with QEMG in different segments of the ventral serratus muscle. Results were compared to normative data. Diagnostic imaging was performed in 28 cases. All horses were euthanized because of poor clinical prognoses and/or recurrent clinical neurological signs despite treatment and underwent necropsy with emphasis on the cervical nervous tissue and vertebrae. Clinical and diagnostic imaging findings, QEMG results and post mortem findings were compared with each other. Results: Overall mean values of duration (9.54 ms), polyphasia, number of phases (3.6) and size index (0.67) in horses with cervical lesions were significantly (P.

INTRODUCTION: Objectifs: Déterminer la relation entre l>électromyographie quantitative (QEMG) du muscle serratus ventral cervical, les résultats radiographiques et les examens macroscopiques et histopathologiques post mortem afin de calculer la capacité de la QEMG à localiser la région de compression neurogène dans l'encolure des chevaux. Méthodes: Dans cette étude clinique, non randomisée, partiellement aveugle (histologie et QEMG), 36 chevaux de sang soupçonnés d'affection du rachis cervical ont été examinés par QEMG sur différents segments du muscle serratus ventral. Les résultats ont été comparés aux données de référence. L'imagerie diagnostique a été réalisée dans 28 cas. Tous les chevaux ont été euthanasiés en raison de mauvais pronostics cliniques et/ou de signes neurologiques cliniques récurrents malgré le traitement et ont subi une autopsie en mettant l'accent sur le tissu nerveux cervical et les vertèbres. Les résultats de l'imagerie clinique et diagnostique, les résultats de la QEMG et les résultats post mortem ont été comparés les uns aux autres. Résultats: Les valeurs moyennes globales de durée (9,54 ms), de polyphasie, de nombre de phases (3,6) et d'indice de taille (0,67) chez les chevaux présentant des lésions cervicales étaient significativement (P.

Cervico-thoracic vertebral subluxation in sheep: Awareness among veterinarians of a rare syndrome.

Cervico-thoracic vertebral subluxation (CTVS) in sheep is a collective term that is used to describe various conditions that concomitantly affect the cervical and thoracic vertebrae, leading to their collapse. The aetiology and pathophysiology of CTVS remain unknown. The objective of this study was to conduct an epidemiological farm investigation and describe the clinicopathological findings of CTVS cases occurring in a flock of sheep; as well as to determine awareness of CTVS among sheep producers and ruminant veterinarians in Australia. Diagnostic imaging revealed severe deformities in the vertebrae between C6-C7 and T1-T3. Sheep affected with CTVS were at a four times higher risk of having low body condition scores (< 2 based on a 5-point scale) compared with non-affected sheep, OR = 3.98, 95% CI (1.20-12.65), p = .02. Survey results revealed that only 34% (15/44) of respondents were aware of CTVS. There is a need to further explore the aetiology and pathophysiology of CTVS, and the impact it has on sheep breeding and production.

Perosomus elumbis in a stillborn rhesus macaque (Macaca mulatta): A case report.

Perosomus Elumbis (PE) is a rare congenital disorder characterized by absence of caudal spine (lumbar, sacral, and coccygeal vertebrae). Here, we present the first reported case of PE in a rhesus macaque (Macaca mulatta) and relate our findings to those described in other species.

Diaphragmatic dysfunction in dogs with cervical spinal disorders before and after surgery using fluoroscopy, motion-mode ultrasound and radiography was not different than a group of control dogs.

Cervical spinal disorders can lead to life-threatening respiratory complications. Diaphragmatic dysfunction is attributed to spinal cord morbidity secondary to cervical myelopathy or decompressive surgical intervention. The purpose of this observational case-control study was to determine the frequency of diaphragmatic dysfunction in dogs with cervical spinal disorders and a control group, the strength of association between cervical myelopathies and decompressive surgery with diaphragm paresis, and the agreement between and clinical usefulness of fluoroscopy, motion-mode ultrasonography, and radiography for diagnosing diaphragmatic dysfunction. Thirty-five client-owned dogs were recruited with 14 control dogs and 21 test dogs. Dogs were evaluated for the presence of diaphragmatic dysfunction using radiography, M-mode ultrasonography, and fluoroscopy before and after an anesthetic or surgical event. Diaphragmatic dysfunction was observed more frequently in dogs with cervical spinal disease prior to surgery (8/21; 38.1%) compared to control dogs (3/14; 21.4%) but was not statistically significant (P = .30). The occurrence of diaphragmatic dysfunction did not significantly increase following surgical decompression in either group. There was no to slight agreement between all imaging modalities. Most dogs with diaphragmatic dysfunction were asymptomatic. Diaphragmatic dysfunction was not statistically associated with cervical myelopathy or decompressive surgery. Ultrasonography and radiography were not useful diagnostic tests for determining diaphragmatic dysfunction in asymptomatic dogs when compared to fluoroscopy.

Vertebral column deformity with curved cross-stitch vertebrae in Norwegian seawater-farmed Atlantic salmon, Salmo salar L.

Pathological changes in the vertebral column of farmed Atlantic salmon in Norway have been reported since the 1990s. Based on the characteristic radiographic findings, we here present a vertebral column deformity named "curved cross-stitch vertebrae" that mainly affects the middle aspect of the vertebral column. Sixty fish, from the west/northwest coast of mid-Norway, were sampled at slaughter and examined by radiography, computed tomography (CT), necropsy, macrophotography, and histology. The vertebral deformities were radiographically graded as mild, moderate, or marked. The main differences between these grades of changes were defined by increased curving of the peripheries of endplates, reduced intervertebral spaces, and vertical displacement of the vertebrae. The curved rims of endplates were located peripheral to a continuous and approximately circular borderline. The CT studies revealed small, multifocal, hypo-attenuating, round to crescent-shaped areas in the notochord, compatible with the presence of gas. Additionally, histology revealed that the axial parts of endplates had circular zones with perforations, through which either notochordal tissue prolapsed into the vertebrae or vascularized fibrochondroid proliferations extended from the vertebrae into the notochord. Inflammation was present in many vertebral bodies. To the best of our knowledge, this is the first report of gas in the notochord of fish.

Clinical management of dogs with presumptive diagnosis of thoracolumbar intervertebral disc disease: 164 cases (2006-2017) / Tratamento clínico de cães com diagnóstico presuntivo de doença do disco intervertebral toracolombar: 164 casos (2006-2017)

This study aimed to identify dogs with presumptive diagnosis of cervical intervertebral disc disease (IVDD) submitted to clinical management and to evaluate the outcomes. Data were obtained from the medical records of patients with neurological dysfunction assisted at a University Veterinary Hospital from 2006 to 2017. In addition to the patients' records, dog owners responded to a questionnaire on the success of therapy. Four hundred and thirteen neurological records were evaluated, and 164 met the inclusion criteria of the study. The most common breed was Dachshund, followed by mongrels. Classification of neurological dysfunction in the study sample was as follows: 15.9% with grade I, 25.6% with grade II, 26.8% with grade III, 8.5% with grade IV, and 23.2% with grade V. Outcome was satisfactory in 71.6% of the dogs and unsatisfactory in 28.4% of them. Recurrence was observed in 27.7% of those with satisfactory outcomes. The clinical treatment of dogs with thoracolumbar IVDD is satisfactory, particularly for animals with milder disease grades (I, II, and III). There is possibility of recurrence with conservative therapy and clinical signs may be more severe.(AU)

O objetivo desse estudo foi identificar cães com diagnóstico presuntivo de DDIV toracolombar submetidos ao tratamento clínico, a fim de avaliar a resposta à terapia instituída. Foram revisados os registros neurológicos de cães atendidos pelo Serviço de Neurologia e Neurocirurgia Veterinária no período de 2006 a 2017 de um Hospital Veterinário Universitário. Foi realizada coleta de dados a partir dos registros e por meio de um questionário respondido pelos tutores. Foram avaliadas 413 fichas neurológicas de cães e obtidas informações para inclusão no estudo em 164 delas. As raças mais frequentes foram dachshunds, seguido de cães sem raça definida. Quanto ao grau de disfunção neurológica foi definido como grau I para 15,9% dos cães, grau II para 25,6%, grau III para 26,8%, grau IV para 8,5% e grau V para 23,2%. A recuperação foi satisfatória em 71,6% dos cães e insatisfatória em 28,4%. Dos que se recuperaram satisfatoriamente, 27,7% tiveram recidivas. Com base nos resultados obtidos pode-se concluir que o tratamento clínico em repouso absoluto e administração de anti-inflamatórios e analgésicos opióides para cães com DDIV toracolombar é efetivo, principalmente para cães em graus mais leves da doença (grau I, II e III). Há possibilidade de recidiva com esse tipo de terapia cujos sinais clínicos poderão ser mais graves.(AU)

Clinical reasoning in feline spinal disease: which combination of clinical information is useful?

OBJECTIVES: The aim of this study was to evaluate if a combination of discrete clinical characteristics can be used to identify the most likely differential diagnoses in cats with spinal disease. METHODS: Two hundred and twenty-one cats referred for further evaluation of spinal disease were included and categorised as follows: non-lymphoid neoplasia (n = 44); intervertebral disc disease (n = 42); fracture/luxation (n = 34); ischaemic myelopathy (n = 22); feline infectious peritonitis virus myelitis (n = 18); lymphoma (n = 16); thoracic vertebral canal stenosis (n = 11); acute non-compressive nucleus pulposus extrusion (n = 11); traumatic spinal cord contusion (n = 8); spinal arachnoid diverticula (n = 7); lumbosacral stenosis (n = 5); and spinal empyema (n = 3). Information retrieved from the medical records included signalment, clinical history and clinical presentation. Univariate analyses of variables (clinical history, breed, age, sex, general physical examination findings, onset, progression, spinal hyperaesthesia, asymmetry, ambulatory status and neuroanatomical location) were performed, and variables were retained in a multivariate logistic regression model if P <0.05. RESULTS: Multivariate logistic regression revealed that intervertebral disc disease most often occurred in middle-aged, purebred cats with a normal general physical examination and an acute onset of painful and progressive clinical signs. Ischaemic myelopathy occurred most often in older cats with a stable or improving, non-painful, lateralising, C6-T2 myelopathy. Spinal fracture/luxation occurred most often in younger cats and resulted most often in a peracute onset, painful, non-ambulatory neurological status. Concurrent systemic abnormalities or abnormal findings detected on general physical examination were significantly associated with feline infectious peritonitis virus myelitis, spinal lymphoma or spinal empyema. CONCLUSIONS AND RELEVANCE: This study suggests that using easily identifiable characteristics from the history and clinical examination can assist in obtaining a preliminary differential diagnosis when evaluating cats with spinal disease. This information could aid veterinary practitioners in clinical decision-making.

Dnmt3a-Mediated DNA Methylation Changes Regulate Osteogenic Differentiation of hMSCs Cultivated in the 3D Scaffolds under Oxidative Stress.

Oxidative stress (OS) caused by multiple factors occurs after the implantation of bone repair materials. DNA methylation plays an important role in the regulation of osteogenic differentiation. Moreover, recent studies suggest that DNA methyltransferases (Dnmts) are involved in bone formation and resorption. However, the effect and mechanism of DNA methylation changes induced by OS on bone formation after implantation still remain unknown. Three-dimensional (3D) cell culture systems are much closer to the real situation than traditional monolayer cell culture systems in mimicking the in vivo microenvironment. We have developed porous 3D scaffolds composed of mineralized collagen type I, which mimics the composition of the extracellular matrix of human bone. Here, we first established a 3D culture model of human mesenchymal stem cells (hMSCs) seeded in the biomimetic scaffolds using 160 µM H2O2 to simulate the microenvironment of osteogenesis after implantation. Our results showed that decreased methylation levels of ALP and RUNX2 were induced by H2O2 treatment in hMSCs cultivated in the 3D scaffolds. Furthermore, we found that Dnmt3a was significantly downregulated in a porcine anterior lumbar interbody fusion model and was confirmed to be reduced by H2O2 treatment using the 3D in vitro model. The hypomethylation of ALP and RUNX2 induced by H2O2 treatment was abolished by Dnmt3a overexpression. Moreover, our findings demonstrated that the Dnmt inhibitor 5-AZA can enhance osteogenic differentiation of hMSCs under OS, evidenced by the increased expression of ALP and RUNX2 accompanied by the decreased DNA methylation of ALP and RUNX2. Taken together, these results suggest that Dnmt3a-mediated DNA methylation changes regulate osteogenic differentiation and 5-AZA can enhance osteogenic differentiation via the hypomethylation of ALP and RUNX2 under OS. The biomimetic 3D scaffolds combined with 5-AZA and antioxidants may serve as a promising novel strategy to improve osteogenesis after implantation.

Flexed radiographic angles for determination of atlantoaxial instability in dogs.

OBJECTIVE: To determine a flexed position for radiographic diagnosis of atlantoaxial instability (AAI) and to identify radiographic measurement cutoffs to differentiate affected dogs from neurologically healthy toy breeds. STUDY DESIGN: Retrospective case series and prospective case controls. ANIMALS: Thirty-nine client-owned toy breed dogs in which AAI had been diagnosed and 20 neurologically healthy client-owned toy breed dogs. METHODS: Medical records from three institutions were retrospectively reviewed to identify dogs affected with AAI. Flexed lateral images were reviewed, and measurements were obtained by using anatomic landmarks. Radiography was performed with control dogs to obtain the same measurements. RESULTS: Flexed lateral radiographs of thirty dogs affected with AAI were found to be positioned at a mean of 51° flexion. When flexed lateral radiographs were evaluated with a cutoff value for atlas to axis angle (AAA) >10°, evaluation of all breeds represented revealed a 90% sensitivity and 90% specificity. When this cutoff was evaluated in Yorkshire terriers, Chihuahuas, and mixes of these breeds, the sensitivity was 92%, and the specificity was 92%. When the control sample was positioned at 51° ± 10°, only two of the dogs were within the AAA cutoff value of >10°. There was no difference between the measurements obtained by using the flexed lateral view (mean = 50.9°) and the exaggerated flexed lateral view (mean = 38.9°) in the control sample. CONCLUSION: This study established objective measurements for the positioning and diagnosis of AAI on flexed lateral radiographs in toy breed dogs. CLINICAL SIGNIFICANCE: Atlantoaxial instability can be objectively diagnosed in sedated or anesthetized toy breed dogs when applying 51° flexion to cervical radiographs.

Instrumented cervical fusion in nine dogs with caudal cervical spondylomyelopathy.

OBJECTIVE: To report the long-term outcome of nine dogs treated for caudal cervical spondylomyelopathy (CCSM) with surgical spinal fusion. STUDY DESIGN: Short case series. ANIMALS: Nine large-breed dogs. METHODS: Medical records of dogs treated for disc-associated CCSM (2013-2016) were reviewed. The surgery objective was spinal distraction by implantation of a SynCage and fixation with two Unilock plates. Follow-up included the Helsinki pain score questionnaire, neurological grading, radiography, computed tomography (CT), and micro-CT (µCT) with subsequent histopathology (two dogs). RESULTS: Clinical follow-up was obtained between 9 and 51 months (27.4 ± 13.4 months). The Helsinki pain score and neurological Griffith score improved (P < .01) in all dogs and in eight of nine dogs, respectively. According to CT, the volume of bone (mean ± SD) through the cage was 79.5% ± 14.3%, including compact bone (53.0% ± 23.4%). Subsidence was seen in one of nine dogs. Implant failure was evident in four dogs, and plates were removed in two dogs. In seven of nine dogs, infraclinical pathology was observed in adjacent segment, associated with implants engaging adjacent intervertebral discs. Radiographic evidence of bony fusion between vertebral bodies was noted in all dogs. Spinal fusion was confirmed by µCT and histopathology in two cervical spine segments that became available at 22 and 40 months postoperatively. CONCLUSION: Instrumented spinal fusion in dogs with disc-associated CCSM resulted in owner satisfaction and radiographic evidence of interbody spinal fusion in all dogs. CLINICAL SIGNIFICANCE: The fusion distraction technique reported here can be used to achieve spinal fusion with a good long-term outcome.