Comparison between Bilateral Ultrasound-Guided Quadratus Lumborum Block and Sacrococcygeal Epidural in Cats Undergoing Ovariectomy.

BACKGROUND: Ultrasound-guided quadratus lumborum block (QLB) and sacrococcygeal epidural anaesthesia (ScE) have been used for neutering cats, providing effective pain relief. OBJECTIVES: To compare the effects of the QLB with those of ScE in cats undergoing ovariectomies. METHODS: Feral cats undergoing ovariectomy were premedicated with dexmedetomidine (20 µg kg-1) and methadone (0.2 mg kg-1) intramuscularly. Anaesthesia was induced with 2-4 mg kg-1 of propofol intravenously and maintained with isoflurane in oxygen. The cats were randomly allocated to the groups QLB (bilateral QLB with 0.4 mL kg-1 of 0.25% bupivacaine) and ScE (0.3 mL kg-1 of 0.25% bupivacaine). Hemodynamic data and analgesia rescue were collected at four intraoperative periods. The pain scale and motor block were assessed in both groups during the postoperative period. RESULTS: The ScE results in increased hypotension, prolonged extubation time, and higher postoperative motor block than the QLB (p < 0.05). The QLB and ScE groups required a similar number of intraoperative rescues and presented the same postoperative pain scale classification. CONCLUSIONS: The QLB with 0.25% bupivacaine is a potential alternative to ScE with 0.25% bupivacaine in perioperative pain management in elective cat ovariectomy. The QLB promoted less hypotension and postoperative motor block when compared with the ScE group.

Guidelines on Developmental Toxicity Tests: Brief Insights.

Developmental toxicology is a constantly evolving research field which needs to attend to a complex underlying regulatory network. In order to ensure human health and environmental safety, new substances have to be tested for toxic effects on reproduction and development, before being commercialized. Traditional in vivo mammalian models represent the intricacy of human development and provide more adequately an assessment of the interaction of chemical compounds with the reproductive system. However, in the last years, the directives are to reduce the use of vertebrate animals, promoting their use only as a last resort. Consequently, the interest on the development and validation of alternative tests, able to cover the various aspects of the reproductive cycle, has significantly increased. Reproductive toxicity is probably the most difficult endpoint to be replaced by alternative assays, since it should provide information on mechanism interactions essential for female and male fertility and also knowledge on the animal development during the first phases of its life cycle. This complexity explains the slow progress in implementing alternative models for reproductive toxicity safety assays. Alternative test models may be based on in vitro systems and nonmammalian animal models. Many biological processes have been successfully addressed using in vitro models, opening the possibility to study the interference of teratogenic compounds. Their validation and implementation have lagged behind, in part because of difficulties in establishing their predictability. Nevertheless, the advance toward the process of validation is crucial to replace and reduce the use of living animals. Based on the present state of the art, it is not probable that such testing strategies will completely replace the need to assess reproductive toxicity in vivo in the near future, but they will contribute to reduce animal tests and will provide important information. In this chapter, the approved guidelines for standard methods and alternative methods, according to their regulatory and scientific status, are enumerated and briefly described.

Development Features on the Selection of Animal Models for Teratogenic Testing.

Today, the use of animal models from different species continues to represent a fundamental step in teratogenic testing, despite the increase in alternative solutions that provide an important screening to the enormous quantity of new substances that aim to enter the market every year. The maintenance of these models is due to the sharing of similar development processes with humans, and in this way they represent an important contribution to the safety in the use of the compounds tested. Furthermore, the application of advances in embryology to teratology, although hampered by the complexity of reproductive processes, continues to prove the importance of sensitivity during embryonic and fetal development to detect potential toxicity, inducing mortality/abortion and malformations.In this chapter, essential periods of development in different models are outlined, highlighting the similarities and differences between species, the advantages and disadvantages of each group, and specific sensitivities for teratogenic testing. Models can be divided into invertebrate species such as earthworms of the species Eisenia fetida/Eisenia andrei, Caenorhabditis elegans, and Drosophila melanogaster, allowing for rapid results and minor ethical concerns. Vertebrate nonmammalian species Xenopus laevis and Danio rerio are important models to assess teratogenic potential later in development with fewer ethical requirements. Finally, the mammalian species Mus musculus, Rattus norvegicus, and Oryctolagus cuniculus, phylogenetically closer to humans, are essential for the assessment of complex specialized processes, occurring later in development.Regulations for the development of toxicology tests require the use of mammalian species. Although ethical concerns and costs limit their use in large-scale screening. On the other hand, invertebrate and vertebrate nonmammalian species are increasing as alternative animal models, as these organisms combine low cost, less ethical requirements, and culture conditions compatible with large-scale screening. Their main advantage is to allow high-throughput screening in a whole-animal context, in contrast to the in vitro techniques, not dependent on the prior identification of a target. Better knowledge of the development pathways of animal models will allow to maximize human translation and reduce the number of animals used, leading to a selection of compounds with an improved safety profile and reduced time to market for new drugs.

Establishment of an ultrasound-guided protocol for the assessment of hip joint osteoarthritis in rabbits-A sonoanatomic study.

Ultrasound (US) has emerged as one of the most applied imaging tools to diagnose musculoskeletal disorders and assist in guided intra-articular administrations. Nevertheless, in evaluating the rabbit hip joint, there is a need for an ultrasonographic approach. Therefore, this study aimed to describe the hip sonoanatomy, develop and validate a US-guided protocol to assess the hip joint in rabbits and apply this protocol in vivo. This study was carried out in three phases, phase I: a pilot cadaveric study, to assess the applicability of different US approaches in the hip of rabbits and, consequently, develop a detailed US-guided protocol (2 rabbit cadavers, n = 4 hips); phase II: validation of the established US-guided protocol through a numerical scoring system in healthy joints (11 rabbit cadavers, n = 22 hips), and, lastly, phase III: application of the US-guided protocol in vivo in osteoarthritic joints (5 rabbits, n = 5 hips). A total of six planes were validated, two in the ventral approach and four in the dorsal approach. The ventral transverse plane was deemed more informative regarding the hip joint sonoanatomy, enabling the identification of a greater number of structures when compared to the other planes. Nevertheless, this study suggested that the isolated application of a plane was deemed insufficient for a complete and detailed evaluation of the hip joint anatomy, rendering it necessary to employ other planes complementarily. Furthermore, the established US-guided protocol allowed a definitive diagnosis of OA, and osteophytes and capsular hypertrophy were among the defects most frequently detected. This novel study provided US anatomical landmarks for forthcoming therapeutic research and monitoring of OA development, granting the accurate identification of osseous and cartilaginous defects.

Femoral Neck Thickness Index as an Indicator of Proximal Femur Bone Modeling.

The alteration in the shape of the femoral neck is an important radiographic sign for scoring canine hip dysplasia (CHD). Previous studies have reported that the femoral neck thickness (FNT) is greater in dogs with hip joint dysplasia, becoming progressively thicker with disease severity. The main objective of this work was to describe a femoral neck thickness index (FNTi) to quantify FNT and to study its association with the degree of CHD using the Fédération Cynologique Internationale (FCI) scheme. A total of 53 dogs (106 hips) were randomly selected for this study. Two examiners performed FNTi estimation to study intra- and inter-examiner reliability and agreement. The paired t-test, the Bland-Altman plots, and the intraclass correlation coefficient showed excellent agreement and reliability between the measurements of the two examiners and the examiners' sessions. All joints were scored in five categories by an experienced examiner according to FCI criteria. The results from examiner 1 were compared between FCI categories. Hips that were assigned an FCI grade of A (n = 19), B (n = 23), C (n = 24), D (n = 24), and E (n = 16) had a mean ± standard deviation FNTi of 0.809 ± 0.024, 0.835 ± 0.044, 0.868 ± 0.022, 0.903 ± 0.033, and 0.923 ± 0.068, respectively (ANOVA, p < 0.05). Therefore, these results show that FNTi is a parameter capable of evaluating proximal femur bone modeling and that it has the potential to enrich conventional CHD scoring criteria if incorporated into a computer-aided diagnosis capable of detecting CHD.

Femoral parallelism: evaluation and impact of variation on canine hip dysplasia assessment.

Adequate radiographic positioning on the X-ray table is paramount for canine hip dysplasia (HD) screening. The aims of this study were to evaluate femoral parallelism on normal ventrodorsal hip extended (VDHE) view and the effect of femoral angulation (FA) on Norberg Angle (NA) and Hip Congruency Index (HCI). The femoral parallelism was evaluated comparing the alignment of the long femoral axis with the long body axis in normal VDHE views and the effect of FA on NA and HCI on repeated VDHE views with different levels of FA. The femoral long axis in normal VDHE views showed a ranged of FA from -4.85° to 5.85°, mean ± standard deviation (SD) of -0.06 ± 2.41°, 95% CI [-4.88, 4.76°]. In the paired views, the mean ± SD femur adduction of 3.69 ± 1.96° led to a statistically significant decrease NA, and HCI, and femur abduction of 2.89 ± 2.12 led to a statistically significant increase in NA and HCI (p < 0.05). The FA differences were also significantly correlated with both NA differences (r = 0.83) and HCI differences (r = 0.44) (p < 0.001). This work describes a methodology that allows evaluation of femoral parallelism in VDHE views and the results suggest that femur abduction yielded more desirable NA and HCI values and adduction impaired NA and HCI values. The positive linear association of FA with NA and HCI allows the use of regression equations to create corrections, to reduce the influence of poor femoral parallelism in the HD scoring.

Active learning for data efficient semantic segmentation of canine bones in radiographs.

X-ray bone semantic segmentation is one crucial task in medical imaging. Due to deep learning's emergence, it was possible to build high-precision models. However, these models require a large quantity of annotated data. Furthermore, semantic segmentation requires pixel-wise labeling, thus being a highly time-consuming task. In the case of hip joints, there is still a need for increased anatomic knowledge due to the intrinsic nature of the femur and acetabulum. Active learning aims to maximize the model's performance with the least possible amount of data. In this work, we propose and compare the use of different queries, including uncertainty and diversity-based queries. Our results show that the proposed methods permit state-of-the-art performance using only 81.02% of the data, with O ( 1 ) time complexity.

Acetabular Coverage Area Occupied by the Femoral Head as an Indicator of Hip Congruency.

Accurate radiographic screening evaluation is essential in the genetic control of canine HD, however, the qualitative assessment of hip congruency introduces some subjectivity, leading to excessive variability in scoring. The main objective of this work was to validate a method-Hip Congruency Index (HCI)-capable of objectively measuring the relationship between the acetabulum and the femoral head and associating it with the level of congruency proposed by the Fédération Cynologique Internationale (FCI), with the aim of incorporating it into a computer vision model that classifies HD autonomously. A total of 200 dogs (400 hips) were randomly selected for the study. All radiographs were scored in five categories by an experienced examiner according to FCI criteria. Two examiners performed HCI measurements on 25 hip radiographs to study intra- and inter-examiner reliability and agreement. Additionally, each examiner measured HCI on their half of the study sample (100 dogs), and the results were compared between FCI categories. The paired t-test and the intraclass correlation coefficient (ICC) showed no evidence of a systematic bias, and there was excellent reliability between the measurements of the two examiners and examiners' sessions. Hips that were assigned an FCI grade of A (n = 120), B (n = 157), C (n = 68), D (n = 38) and E (n = 17) had a mean HCI of 0.739 ± 0.044, 0.666 ± 0.052, 0.605 ± 0.055, 0.494 ± 0.070 and 0.374 ± 0.122, respectively (ANOVA, p < 0.01). Therefore, these results show that HCI is a parameter capable of estimating hip congruency and has the potential to enrich conventional HD scoring criteria if incorporated into an artificial intelligence algorithm competent in diagnosing HD.

Comparison of dorsoventral and ventrodorsal approaches for ultrasound-guided quadratus lumborum block in cats: a cadaver study.

OBJECTIVE: To assess the feasibility of an ultrasound (US)-guided quadratus lumborum (QL)-psoas muscle (Pm) interfascial plane injection using a dorsoventral (DV) approach, and to compare needle visualization and distribution pattern between DV and ventrodorsal (VD) approaches. STUDY DESIGN: Experimental anatomical study. ANIMALS: A total of 14 cat cadavers. METHODS: Bilateral in-plane US-guided injections in the QL-Pm plane were performed at the level of the second lumbar (L2) transverse process. A spinal needle was inserted using either a VD or DV approach. A total volume of 0.4 mL kg-1 of a solution of ropivacaine 0.18%, tissue dye and iohexol (350 mg mL-1), in a proportion of 3:1:1, respectively, was injected bilaterally. Spread of injectate was compared and evaluated using US, computed tomography (CT) scanning and anatomical dissection. Presence of dye on the sympathetic trunk was compared between methods using Kappa (κ) coefficient of agreement. RESULTS: The QL-Pm plane was visualized, and dye was present in the target plane using both approaches. Needle visualization in the VD approach was enhanced compared with the DV approach (p = 0.0005). Mean distribution along the sympathetic trunk was 4.8 and 4.1 segments in the VD and DV approaches, respectively, showing non-statistical differences. The ventral branches of L1, L2 and L3 were successfully stained in 11/14 and 6/14 using the VD and DV approaches, respectively. Substantial agreement (κ = 0.61) of sympathetic trunk staining was observed between CT scan and anatomical dissection. Dye was observed cranial to the diaphragm in 7/8 cases on CT with both approaches. Epidural and abdominal cavity dye distribution was not observed. CONCLUSIONS AND CLINICAL RELEVANCE: The DV approach to the QL-Pm plane could be an alternative to the VD approach. Both approaches seem capable of reaching the spinal nerves, the sympathetic trunk and both splanchnic and coeliac nerves in feline cadavers.

Early hip laxity screening and later canine hip dysplasia development.

Background and Aim: Passive hip laxity (PHL) is considered the primary risk factor for canine hip dysplasia (HD) and is estimated, in stress hip radiographs, using the distraction index (DI). The study aimed to associate the early PHL using the hip Distractor of University of Trás-os-Montes and Alto Douro (DisUTAD) and the late HD grades. Materials and Methods: A total of 41 dogs (82 hips) were submitted to a follow-up study. First, between 4 and 12 months of age, dogs were radiographed using the DisUTAD hip distractor and were determined the DI for each hip joint. Then, after 12 months of age, dogs were reevaluated for HD using the conventional hip ventrodorsal projection and hips were evaluated for HD using the Fédération Cynologique Internationale (FCI) scoring system. Results: Hips of dogs' in the second examination with FCI grades of A (n=28), B (n=11), C (n=22), and D and E (n=21) had an early DI of 0.32±0.1, 0.38±0.08, 0.50±0.12, and 0.64±0.11, respectively. Statistical analysis using the general linear model univariate, with the DI as dependent variable and the FCI grades, side and sex as fixed factors, and the post hoc Bonferroni correction test showed significant differences among FCI grades (p<0.05). Conclusion: These results show the association between early DI and the late FCI HD grades and the DisUTAD is recommended for the early canine HD diagnosis.

Effect of elbow angle and weight-bearing on the evaluation of joint congruence in dogs.

Joint congruence is relevant for the assessment of elbow dysplasia, a development disorder in dogs. However, quantification of its variation with joint angle and weight-bearing, important factors in quadrupedal locomotion, is lacking. Our objective was to estimate those effects on the alignment of humeroradioulnar joint surfaces. The usual protocol for screening elbow dysplasia, including mediolateral extended and flexed elbow views, was preceded by a weight-bearing lateromedial standing radiographic view, without sedation. Minimum distances were measured at established points of the humeroradioulnar joints classified with a Grade 0 dysplasia. Sixty elbows (30 Portuguese Pointer dogs) were studied. The joint space between the anconeal process and the ulnar trochlear notch increased with flexion, decreasing with weight-bearing (p < .001). The distance between the humeral trochlea and the trochlear notch at the widest point increased with weight-bearing, while it decreased with flexion. Step and distance between the radial head and the base of the medial coronoid process increased with flexion and decreased with weight-bearing. At this point, physiological changes occurred at the humeroulnar joint space. The methodology allowed to quantify the variations on joint spaces with the elbow angle and weight-bearing, important for the interpretation of congruence in diagnosis and treatment of dysplasia. Reference absolute and indexed values obtained allow future comparisons with other breeds and dysplastic dogs. Physiological variations denoted that radioulnar joint became more incongruent under flexion, and more congruent under weight-bearing, while humeroulnar joint became more congruent under flexion, and more incongruent under weight-bearing.

A description of an ultrasound-guided technique for a quadratus lumborum block in the cat: a cadaver study.

OBJECTIVES: To describe the ultrasonographic (US) anatomy of the sublumbar region at the level of second lumbar vertebra (L2), to assess the feasibility of US-guided quadratus lumborum (QL) injections and to evaluate the dye distribution pattern in feline cadavers. STUDY DESIGN: Descriptive feline cadaver study. ANIMALS: A total of eight cat cadavers. METHODS: Using a linear probe (6-14 MHz), with the cadavers in lateral recumbency, the QL and psoas muscles (Pm) were identified at the level of L2 and landmarks recorded. Using an in-plane technique, a spinal needle was inserted in a ventrodorsal direction to reach the interfascial plane between the QL and Pm. Using a ropivacaine, dye and iohexol solution, a total volume of 0.4 mL kg-1 was injected. Computed tomography (CT) scanning and anatomic dissection were performed to evaluate the spread of injectate. Presence of dye on the sympathetic trunk was compared between assessment methods using kappa coefficient of agreement (κ). RESULTS: Using US guidance, the QL-Pm interfascial plane was identified and dye solution was present in the target fascial plane in all animals. Injectate was distributed on the ventral roots of the spinal nerves between the first and third lumbar vertebrae in 6/8 cats, and on the sympathetic trunk from the thirteenth thoracic to the third lumbar vertebrae in 7/8. Dye was found on the major splanchnic nerve in 7/8 cats and on the minor splanchnic nerve and coeliac ganglion pathways in all animals. Agreement between dissection and CT images dye distribution on the sympathetic trunk was κ = 0.72. CONCLUSIONS AND CLINICAL RELEVANCE: The US-guided QL injection was feasible and injectate was present in the QL-Pm interfascial plane in all feline cadavers. In vivo studies are warranted to evaluate the analgesic efficacy of this technique for abdominal surgical procedures.

Imaging diagnosis of canine hip dysplasia with and without human exposure to ionizing radiation.

Hip dysplasia (HD) is one of the most common hereditary orthopaedic diseases in dogs, with serious implications for the quality of life of the affected animals. Radiographic screening is essential for the selection of breeding stock in some at-risk breeds, and radiography is also used in the diagnosis of clinical HD cases. A definitive diagnosis of HD is based on radiographic examination, and the most commonly used view is the ventrodorsal hip extended projection, sometimes in combination with various hip stress-based techniques. Radiographic images require high quality positioning and dogs are usually anesthetized and often manually restrained to facilitate optimal positioning. The 'as low as reasonably achievable' (ALARA) principle used in human radioprotection is not always fulfilled in veterinary practice, except in the UK, where human exposure to ionizing radiation in veterinary medicine is strictly regulated. While each dose of ionizing radiation is small, doses accumulate over a lifetime, which can eventually result in substantial radiation exposure. Therefore, manual restraint should be avoided and mechanical immobilization, sedation or general anaesthesia should be used. This review examines the biological effects of human exposure to ionizing radiation and common sources of veterinary exposure. The diagnostic quality of imaging methods for the diagnosis of canine HD is compared between manually restrained and hands-free dog positioning. Hands-free radiographic techniques are available to assess hip laxity, degenerative joint changes and hip osseous structure while preserving image quality, and can be used to select animals for breeding or for the diagnosis of HD.

Digital Analysis of Subtrochlear Sclerosis in Elbows Submitted for Dysplasia Screening.

Ulnar trochlear notch (UTN) subchondral bone sclerosis is observed in elbow dysplasia (ED) associated with the medial coronoid disease. However, its evaluation is based on a simple visual examiner assessment of bone radio-opacity level and is considered subjective. The purpose of this study was to objectively characterize the radiographic opacity of the ulnar trochlear notch (UTN) subchondral bone in mediolateral elbow projections classified, using the International Elbow Working Group guidelines. Records and mediolateral flexed elbow images from the Danish Kennel Club database for the ED screening scheme between 2012 and 2018 were available. Of the dogs in the database, those with an ED-negative status in the left limb were identified. From these, 20 dogs each having a status free from ED, or with Grade 1, 2, or 3 in the right limb, were randomly chosen. Joints with primary ununited anconeal process were excluded from the sample. A template was developed using the ImageJ software, for computer UTN sclerosis analysis. It was overlaid onto each image to define five regions of interest (ROIs): ROI-1, distal UTN; ROI-2, middle UTN; ROI-3, caudal UTN; ROI-4, cortical bone; and ROI-5, bone marrow. Mean pixel intensity for each UTN ROI was divided by the mean pixel intensity of ROI-4 to normalize the data. The mean ± standard deviation (SD) of the normalized pixel intensity in the disease joints (ED Grades 1, 2, and 3) was 1.18 ± 0.17, 1.03 ± 0.12, and 0.92 ± 0.09 for ROIs 1, 2, and 3, respectively. The corresponding values for the contralateral normal left joints were 1.16 ± 0.17, 1.01 ± 0.1, and 0.91 ± 0.08. There was a significant difference (P < 0.05) in the normalized mean pixel intensity in dysplastic vs. non-dysplastic elbow joints for ROIs 1 and 2. The raw mean pixel intensity from right and left cortical and marrow bone ROIs sometimes showed relatively large differences. Digital radiography is associated with exposure and post-processing variabilities. Differences in apparent radio-opacity (as indicated by pixel intensity) though statistically significant in dysplastic joints compared with contralateral normal joints are slight and are thus problematic for computer-aided assessments of UTN sclerosis.

Comparison of Two Distraction Devices for Assessment of Passive Hip Laxity in Dogs.

Canine hip dysplasia is the most common orthopedic developmental condition in the dog and early hip laxity is the main risk factor. The importance of hip laxity in young animals in the development of hip dysplasia is unanimously recognized among researchers and veterinarians due to its medical applicability in terms of disease control and prevention. In the market, there is some certified hip distractors to promote joint laxity. However, the clinical use of some of these distractors complies with a set of usage rules, that can limit its medical application. In this study was compared the technical quality of radiographs and hip distraction using a certified hip distractor (CertD) and Dis-UTAD in 104 dogs (208 joints). The mean pelvic tilting of 1.5 ± 1.6° and 1.5 ± 1.8° were similar when using the CertD and the Dis-UTAD distractors, respectively (P > 0.05). In the CertD sample, the mean hip distraction index (DI) was 0.46 ± 0.17 and in the Dis-UTAD 0.46 ± 0.16; the mean DI differences was 0.001 ± 0.045, resulting in a non-significant paired t-test (P = 0.65) and a significant intraclass correlation coefficient of 0.96, with the 95% lower limit confidence interval of 0.95 (P < 0.05). The statistical power analysis showed a very low distraction index difference effect size. The results suggest that the statistical reproducibility of CertD hip distraction by the Dis-UTAD and the DI mean differences of 0.001 might be considered without clinical importance. The Dis-UTAD might be considered adequate to promote dog hip laxity.

Hands-Free Conventional Radiographic Ventrodorsal Hip Extended View.

Hip dysplasia (HD) is an important hereditary orthopedic disease in the dog associated with osteoarthritis and inadequate welfare for affected animals. The radiographic ventrodorsal hip extended (VDHE) view is used worldwide to select the better animals for breeding. This view normally is performed with manual restraining of the dog to obtain radiographs with acceptable technical quality. The veterinarian exposition to ionizing radiation is inevitable. In this study, the technical quality of VDHE radiographs and hip measurements was compared in 65 dogs radiographed twice, one with the common veterinarian manual restraining and the other obtained using a hind limb holder device, without the veterinarian within the X-ray room. The variables studied were pelvic tilting, patella displacement index, Norberg angle (NA), and subluxation hip category. The results showed a random distribution of right and left pelvic tilting, patella lateral or medial displacement, and hip subluxation categories in both samples (P > 0.05). The holder device positioning showed a better pelvic symmetry (P < 0.05) and a similar patellar displacement (P > 0.05). The mean ± standard deviation of NA was 101.1° ± 6.2° and 100.9° ± 6.1° in the manual and holder device hind limb restraining, respectively (P > 0.05), and the lower limit of 95% confidence interval of intraclass correlation coefficient was >0.75. These results showed statistical reproducibility of NA measurements by the hind limb holder device, and the examiner was protected from exposure to ionizing radiation within the X-ray room.

Effect of the Dog positioning on X-Ray Table on Hip Dysplasia Parameter Evaluation.

OBJECTIVE: The aim of this study was to evaluate the effect of pelvic tilting along the long axis and femoral rotation on Norberg angle (NA), subluxation index (SI) and subluxation category (SC) in the standard ventrodorsal hip extended (VDHE) radiographical view on live animals. STUDY TYPE: This was a retrospective clinical study. MATERIALS AND METHODS: Pairs of VDHE views, one adequately positioned and the other with pelvic tilting or femoral internal or external rotation, were compared for the NA, SI and SC. RESULTS: On the malpositioned pelvis set, on the underside the mean ± SD NA was 98.7 ± 6.1°, the SI was 0.27 ± 0.12 and the SC was 2.8 ± 0.8 versus, on the acceptable set, the NA was 99.2 ± 6.4° (p > 0.05), the SI was 0.25 ± 0.12 (p < 0.05) and the SC was 2.3 ± 0.9 (p < 0.05); on the malpositioned upperside, the NA was 102.1 ± 6.4°, the SI was 0.21 ± 0.14 and the SC was 1.7 ± 1.1 versus, on the acceptable positioned set, the NA was 100.8 ± 6.7° (p < 0.05), the SI was 0.24 ± 0.15 (p < 0.05) and the SC was 2.3 ± 1.2 (p < 0.05). Femoral internal or external rotation sets did not show significant differences between malpositioned and acceptable positioned sets (p > 0.05). CONCLUSIONS: In clinical practice, pelvic tilting along the long axis in VDHE view results in non-favourable hip changes in the NA, SI and SC on the underside and favourable on the upperside, and the internal or external femoral rotation did not affect these variables.

Role of Elbow Incongruity in Canine Elbow Dysplasia: Advances in Diagnostics and Biomechanics.

Elbow incongruity plays an important role in the development of elbow dysplasia and its diagnosis can be challenging. The objectives of this systematic review were to discuss elbow biomechanics and recent advances in the assessment of incongruity, to revise the diagnostic protocols suggested, debate advantages and disadvantages of measurements proposed to characterize the joint and improve screening.In spite of advances in the understanding of elbow incongruity, the exact mechanisms involved are not fully elucidated. The elbow is a complex joint and structures in contact differ in different phases of the gait cycle. Advances in the biomechanical field allowed new discoveries and a physiological type of incongruity was described. The next challenge is to unravel the dynamic incongruity. Radiology and computed tomography (CT) are nowadays the imaging tools more applied in clinical practice to quantify incongruity. But a CT standardized screening protocol is required. Most reported findings of incongruity were increased articular joint spaces. The proximity of joint structures and standardization of elbow positioning are identified as the main obstacles to a good interpretation. This review serves to highlight controversy between physiological types of cartilage covering described and pathological changes reported in arthroscopic studies. Radioulnar incongruity was reported more often than humeroulnar incongruity, yet prevalence studies are lacking. Sensitive and reproducible methodologies are in development, which seem primordial to assess the phenotypic heterogeneity.

Teratology Study Guidelines: An Overview.

Developmental toxicology is a constantly evolving research field which needs to attend to a complex underlying regulatory network. Before entering the market new substances have to be tested for toxic effects on reproduction and development in order to ensure human health and environmental safety. Traditional in vivo mammalian models represent more adequately the intricacy of human development and provide an assessment of the interaction of chemicals on the reproductive system. However, in the last years, the main goal is to reduce the use of vertebrate animals, using those only as last resort. Consequently, the interest in the development and validation of a battery of alternative tests able to cover the various aspects of the reproductive cycle has increased. Reproductive toxicity is probably the most difficult endpoint to be replaced by alternative assays, since it should provide information on mechanisms interactions essential for female and male fertility, and also knowledge on the development of a new human being during its prenatal life. This complexity explains the slow progress in implementing alternatives for reproductive toxicity safety assessments. Alternative test methods may be based on in vitro systems and non-mammalian animal models. Many biological processes have been successfully implemented using in vitro models, opening the possibility to study the interference of teratogenic compounds using these models. Their validation and implementation have lagged behind, in part because of difficulties in establishing their predictability. Nevertheless, the advance toward the process of validation is crucial for a strategy aiming to replace and reduce the use of living animals. Based on the present state of the art, it is not probable that such testing strategies will completely replace the need to assess reproductive toxicity in vivo in the near future, but they contribute to reduce the animal testing and provide important information. In this chapter the approved guidelines for standard methods and alternative methods according to their regulatory and scientific status are enumerated and described.

Biological Concerns on the Selection of Animal Models for Teratogenic Testing.

During pregnancy fetus can be exposed to a variety of chemicals which may induce abortion and malformations. Due to the amounts of new substances coming into the market every year, a high demand for a rapid, reliable, and cost-effective method to detect potential toxicity is necessary. Different species have been used as animal models for teratogen screening, most of them sharing similar development processes with humans. However, the application of embryology knowledge to teratology is hampered by the complexity of the reproduction processes.The present chapter outlines the essential development periods in different models, and highlights the similarities and differences between species, advantages and disadvantages of each group, and specific sensitivities for teratogenic tests. These models can be organized into the following categories: (1) invertebrate species such Caenorhabditis elegans and Drosophila melanogaster, which have become ideal for screening simple mechanisms in the early periods of reproductive cycle, allowing for rapid results and minor ethical concerns; (2) vertebrate nonmammalian species such Xenopus laevis and Danio rerio, important models to assess teratogenic potential in later development with fewer ethical requirements; and (3) the mammalian species Mus musculus, Rattus norvegicus, and Oryctolagus cuniculus, phylogenetically more close to humans, essential to assess complex specialized processes, that occur later in development.Rules for development toxicology tests require the use of mammalian species. However, ethical concerns and costs limit their use in large-scale screening. By contrast, invertebrate and vertebrate nonmammalian species are increasing as alternative animal models, as these organisms combine less ethical requirements, low costs and culture conditions compatible with large-scale screening. In contrast to the in vitro techniques, their main advantage is to allow for high-throughput screening in a whole-animal context, not dependent on the prior identification of a target. In this chapter, the biological development of the animals most used in teratogenic tests is adressed with the aims of maximizing human translation, reducing the number of animals used, and the time to market for new drugs.