Prognostic value of power doppler ultrasonography for equine superficial digital flexor tendon injury in thoroughbred racehorses.

The potential value of hypervascularity detected with power Doppler ultrasonography (PDU) within equine superficial digital flexor tendon (SDFT) as a prognostic factor of SDFT injury is not clear. The purpose of this study was to test the hypothesis that hypervascularity within SDFT is one of the risk factors for subsequent severe SDFT injury and to evaluate the prognostic value. A prospective cohort study of 97 Thoroughbred racehorses without any clinical signs of SDFT injury was conducted. Six variables of age, body weight, sex, the cross-sectional area of SDFT, PDU signal within SDFT and experience of steeplechase were assessed for the possibility of risk factors of subsequent SDFT injury in follow-up period of 1 year. Multivariable logistic regression analyses were used for assessment of the odds ratios (ORs) and 95 % confidence intervals (CIs) of SDFT injury. Multivariable logistic regression analysis revealed that the PDU signal within SDFT was a risk factor for the development of SDFT injury in follow-up period (P = 0.017). The adjusted OR of SDFT injury was significantly higher in PDU positive group than in PDU negative group (OR 3.17, 95 % CIs 1.20-8.35). Although further studies are required, these results would be useful for early detection and/or prevention of development for clinical severe SDFT injury.

Using accelerometers to identify a high risk of catastrophic musculoskeletal injury in three racing Thoroughbreds.

OBJECTIVE: To describe the process whereby the screening of racing Thoroughbreds with accelerometer-based inertial measurement unit (IMU) sensors followed by clinical evaluation and advanced imaging identified potentially catastrophic musculoskeletal injuries in 3 horses. ANIMALS: 3 Thoroughbred racehorses. CLINICAL PRESENTATION: All cases demonstrated an abnormal stride pattern either during racing (cases 1 and 2) or while breezing (case 3) and were identified as being at very high risk of catastrophic musculoskeletal injury by an algorithm derived from IMU sensor files from > 20,000 horses' race starts. Veterinary examination and 18F-sodium fluoride (18F-NaF) positron emission tomography were performed within 10 days of the respective race or breeze in each of the cases. RESULTS: The intensity and location of the 18F-NaF uptake in the condyles of the third metacarpal bone in cases 1 and 2 identified them as at potential increased risk of condylar fracture. The pattern and intensity of the 18F-NaF uptake in case 3 indicated that the third carpal bone was likely responsible for the horse's lameness, with an impending slab fracture subsequently identified on radiographs. Following periods of convalescence, cases 1 and 2 returned to racing and were identified by the sensor system as no longer being at high risk of catastrophic musculoskeletal injury. Case 3 returned to training but has yet to return to racing. CLINICAL RELEVANCE: When worn by Thoroughbreds while racing or breezing, these IMU sensors can identify horses at high risk of catastrophic musculoskeletal injury, allowing for veterinary intervention and the potential avoidance of such injuries.

Dermoid cysts formation is a complication of wound pinch grafting in a horse: A case report.

OBJECTIVES: To describe dermoid cyst formation as an uncommon complication of the pinch grafting technique in horses. STUDY DESIGN: Case report. ANIMAL: A 8 year old Arabian gelding. METHODS: Clinical presentation, imaging, treatment, and histopathology records were reviewed. The horse originally presented due to delayed healing of a laceration to the distal aspect of the metatarsus. The wound was treated initially with debridement and it was allowed to fill with healthy granulation tissue prior to pinch grafting. Two months after grafting, the horse started to show self-mutilation behavior targeting the wound site. Ultrasonographic examination revealed the presence of cystic lesions in the subcutaneous tissue in the wound bed and adjacent to the long digital extensor tendon. RESULTS: Treatment involved surgical excision of the cysts, which resulted in a resolution of the self-mutilation episodes. The specimens were submitted for histopathological investigation, which revealed findings compatible with dermoid cyst formation, suspected to be secondary to the skin-grafting procedure. CONCLUSION: Dermoid cysts formation should be considered as a potential differential diagnosis for skin graft complications in horses.

[Navicular bone fractures in horses: Prognosis after conservative and surgical treatment]. / Strahlbein-Frakturen beim Pferd: Prognose nach konservativer und chirurgischer Therapie.

INTRODUCTION: The aim of this retrospective study is to describe and compare conservative and surgical treatment of navicular fractures in horses. An attempt is made to identify critical points that can favorably influence the prognosis of this orthopedic disease. All horses treated for a navicular fracture at the Equine Clinic, Vetsuisse Faculty, University of Zurich between 2005 and 2017 were included in this study. The severity of lameness at initial examination, radiographic assessment, hoof conformation, treatment (conservative or surgical), complications and outcome were determined from the medical records. Conservative and surgical treatment consisted of stable rest, a controlled exercise program and therapeutic orthopedic shoeing. During surgical treatment, fracture reduction was also carried out with a cortical screw. Computer assisted surgery were used in five horses and computer tomography in three horses. Follow-up examinations included clinical and radiographic examinations. The outcome was divided into three categories: 1 = very good; 2 = good; 3 = poor. Twelve horses met the inclusion criteria; Four horses were treated conservatively and eight were treated surgically. After conservative treatment, two horses (50 %) had a very good outcome and two (50 %) had a good outcome. After surgical treatment, four horses (50 %) had a very good outcome and four (50 %) had a poor outcome. Overall, 67 % of horses had a very good or good outcome, although radiographic signs of bone healing was not present in any of these cases. Various complications were identified, such as the fracture of a screw, the fragmentation of the small navicular bone fragment, the development of osteoarthrosis in the coffin joint and progressive podotrochosis. This study shows that the prognosis of navicular fractures is generally cautious and that degenerative changes to the navicular apparatus worsen the prognosis. In the present study, surgical treatment did not improve the prognosis of navicular fractures despite the intrasurgical use of three-dimensional imaging. However, technical advances could reduce the complication rate in the future.

INTRODUCTION: Le but de cette étude rétrospective était de décrire et de comparer le traitement conservateur et chirurgical des fractures de l'os naviculaires chez le cheval. Une tentative est faite pour identifier les points critiques qui peuvent influencer favorablement le pronostic de cette maladie orthopédique. Tous les chevaux traités pour une fracture de l'os naviculaire à la Clinique équine de la Faculté Vetsuisse de l'Université de Zurich entre 2005 et 2017 ont été inclus dans cette étude. La gravité de la boiterie lors de l'examen initial, l'évaluation radiographique, la conformation du sabot, le traitement (conservateur ou chirurgical), les complications et le résultat ont été déterminés à partir des dossiers médicaux. Le traitement conservateur et chirurgical consistait en un repos au box, un programme d'exercice contrôlé et un ferrage orthopédique thérapeutique. Au cours du traitement chirurgical, une réduction de la fracture a également été effectuée à l'aide d'une vis corticale. La chirurgie assistée par ordinateur a été utilisée sur cinq chevaux et la tomographie assistée par ordinateur sur trois chevaux. Les examens de suivi comprenaient des examens cliniques et radiographiques. Les résultats ont été divisés en trois catégories: 1 = très bon; 2 = bon; 3 = mauvais. Douze chevaux répondaient aux critères d'inclusion ; quatre chevaux ont été traités de manière conservatrice et huit ont été traités chirurgicalement. Après un traitement conservateur, deux chevaux (50 %) ont eu un très bon résultat et deux (50 %) un bon résultat. Après le traitement chirurgical, quatre chevaux (50 %) ont eu un très bon résultat et quatre (50 %) un mauvais résultat. Dans l'ensemble, 67 % des chevaux ont eu un très bon ou un bon résultat, bien que les signes radiographiques de guérison osseuse n'aient été présents dans aucun de ces cas. Diverses complications ont été identifiées, telles que la fracture d'une vis, la fragmentation du petit fragment de l'os naviculaire, le développement d'une arthrose dans l'articulation interphalangienne distale et une podotrochlose progressive. Cette étude montre que le pronostic des fractures de l'os naviculaire est généralement réservé et que les modifications dégénératives de l'appareil naviculaire aggravent le pronostic. Dans la présente étude, le traitement chirurgical n'a pas amélioré le pronostic des fractures du naviculaire malgré l'utilisation intra-chirurgicale de l'imagerie tridimensionnelle. Cependant, les progrès techniques pourraient réduire le taux de complications dans le futur.

Stem cells and platelet-rich plasma for the treatment of naturally occurring equine tendon and ligament injuries: a systematic review and meta-analysis.

BACKGROUND: Platelet-rich plasma (PRP) and mesenchymal stromal or stem cells (MSCs) have been investigated as treatments for equine tendon and ligament injuries, but little consensus exists on the efficacy of these treatments. The study sought to evaluate the efficacy of PRP and MSC treatments by systematic review and meta-analysis. METHODS: A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Inclusion criteria required an original, peer-reviewed study where horses were administered MSCs or PRP (or both), and a comparator group was described. Studies were assessed for risk of bias and study quality. Random effects meta-analysis with inverse variance weighting was used to calculate pooled estimates of the ORs for the primary outcomes of return to performance and reinjury. RESULTS: The search criteria identified 764 unique studies, and 21 studies met the inclusion criteria for the systematic review. Seventeen studies were further assessed for the primary outcomes of return to performance and reinjury rate within a meta-analysis. Meta-analyses revealed no increase in the likelihood of a return to performance with any of the biologic treatments. However, MSCs and MSCs administered concurrently with PRP provide a reduced risk of reinjury. CLINICAL RELEVANCE: The current study identified a decrease in reinjury rate in horses administered MSCs or a combination of MSCs and PRP for tendinopathy and desmopathy. However, results should be interpreted with consideration of the heterogeneity of findings, poor study quality, and high risk of bias in the majority of studies.

Associations between turn out practices and rates of musculoskeletal disease and injury in Thoroughbred foals and yearlings on stud farms in the United Kingdom.

BACKGROUND: Early-life locomotor activity during turn out may alter susceptibility to musculoskeletal disease and injury via modulation of behaviours and tissue development during growth. OBJECTIVES: Investigate associations between turn out practices and rates of musculoskeletal disease and injury in young Thoroughbreds on stud farms in the United Kingdom. STUDY DESIGN: Prospective cohort. METHODS: Daily records were kept on location and duration of turn out for 134 Thoroughbred foals on six stud farms, from birth until leaving the farm or study exit. Data on veterinary-attended episodes of musculoskeletal disease or injury were collated concurrently. Average daily turn out times (hours), areas (acres) and group size (n foals) were calculated for rolling 7- and 30-day periods of age. Multivariable Cox regression, including farm as a random effect, was used to investigate associations between turn out practices and musculoskeletal disease and injury. RESULTS: The overall incidence of musculoskeletal disease or injury was 5.3 cases/100 foal-months at risk (95% confidence interval [CI]: 4.2-6.6). Compared with 24/7 turn out, average daily turn out times of between 9 and 23 hours over a 7-day period were associated with a 4.6-fold increase in musculoskeletal injury rate (95% CI: 1.7-12.3; P < 0.001), adjusting for farm and paddock area. Each 1-acre increase in the average daily turn out area during the 4th month of life, reduced the rate of musculoskeletal disease and injury between 6 and 18 months of age by 24% (hazard ratio 0.76, 95% CI: 0.58-0.99; P < 0.001), adjusting for farm and turn out time. MAIN LIMITATIONS: Non-random sample of participants may affect generalisability. Use of veterinary-attended events likely underestimates disease/injury rates. CONCLUSIONS: Results suggest that disruptions or alterations to turn out time routines increase injury risk and should be avoided where possible. Turn out in larger paddocks, particularly before weaning, may confer protection against subsequent musculoskeletal disease and injury.

Comparison of Two Bandage Splint Constructs in an Ex Vivo Equine Metacarpal Fracture Model.

OBJECTIVES: The aim of this study was to compare the deflection distance, deflection angle and pre-loading sub-bandage pressure of a transverse, mid-metacarpal fracture in an equine cadaver limb when loaded in bending while stabilized with either a Robert Jones Bandage (RJB) or a single-stack bandage (SS), each containing two orthogonal splints. STUDY DESIGN: In an ex vivo experimental study, forelimb pairs from eight horses were collected, and one forelimb from each pair was assigned to either the SS or RJB groups. A transverse osteotomy was performed at the midpoint of the metacarpus. After bandaging, the limbs were loaded in bending. Pre-loading sub-bandage pressure, pre- and post-loading radiographs and post-loading deflection distance measurements were taken. Dorsopalmar radiographs were used to measure the loaded deflection angle. RESULTS: There was no significant difference between RJB and SS constructs in change in deflection angle (10.7 ± 3.0 degrees vs. 9.8 ± 2.6 degrees; p = 0.5) or deflection distance (13.1 ± 2.6 cm vs. 11.4 ± 3.1 cm; p = 0.2). Sub-bandage pressures were significantly greater for the SS than the RJB both dorsally and laterally. CONCLUSION: The SS splint construct resists bending forces similarly to the RJB splint construct in an ex vivo transverse, metacarpal fracture model. The SS splint construct may be a useful alternative to the RJB splint construct in field situations for metacarpal fracture stabilization.

Therapeutics prior to mesenchymal stromal cell therapy improves outcome in equine orthopedic injuries.

OBJECTIVE: Mesenchymal stromal (stem) cells (MSCs) have been studied to treat many common orthopedic injuries in horses. However, there is limited information available on when and how to use this treatment effectively. The aim of this retrospective study is to report case features, treatment protocols, and clinical outcomes in horses treated with MSCs. ANIMALS: 65 horses presenting with tendinous, ligamentous, and articular injuries, and treated with MSCs prepared by a single laboratory between 2016 and 2019. Outcome information was available for 26 horses. PROCEDURES: Signalment, clinical signs, diagnostic methods, treatment protocol features (prior and concurrent therapies, cell origin, dose, application site and number), and effective outcomes were analyzed. The analysis was focused on comparing the effect of different MSC treatment protocols (eg, autologous vs allogeneic) on outcome rather than the effectiveness of MSC treatment. RESULTS: MSC treatment resulted in 59.1% (clinical lameness) to 76.9% (imaging structure) improvement in horses with diverse ages, breeds, sex, and lesions. The use of other therapeutic methods before MSC application (eg, anti-inflammatories, shockwave, laser, icing, resting, bandage and stack wrap, intra-articular injections, and/or surgical debridement) was shown to be statistically more effective compared to MSCs used as the primary therapeutic procedure (P < .05). Autologous versus allogeneic treatment outcomes were not significantly different. CLINICAL RELEVANCE: A prospective MSC treatment study with standardization and controls to evaluate the different features of MSC treatment protocols is needed. The various case presentations and treatment protocols evaluated can be used to inform practitioners who are currently using MSCs in clinical practice.

Healing time of experimentally induced distal limb wounds in horses is not reduced by local injection of equine-origin liquid amnion allograft.

OBJECTIVE: To assess the efficacy of an equine-origin liquid amnion allograft (ELAA) derived from both amniotic fluid and amniotic membrane on the healing time of experimentally induced distal limb wounds in horses. ANIMALS: 8 adult horses. PROCEDURES: On day 0, horses were anesthetized and a 2.5 X 2.5-cm, full-thickness skin wound was created on the dorsal aspect of each metacarpus and bandaged. On day 9, wound margins were injected with ELAA (treatment) or 0.9% NaCl (control). Bandages were changed at specific intervals through day 91 and, on each occasion, wounds were photographed to allow calculation of wound area. Exuberant granulation tissue was resected, if present. Wounds were deemed healed when completely epithelialized. Mean wound area was compared between groups throughout the study period. RESULTS: Only 1 wound (control) remained unhealed at day 91. No difference was found between the treatment and control groups in either wound area over time (P = 1.0) or time for wounds to reduce in size by 95% (P = .2) Exuberant granulation tissue required resection twice (1 control wound and 1 treatment wound). CLINICAL RELEVANCE: In this model, a single treatment with ELAA administered locally by SC injection did not accelerate distal limb wound healing in horses. However, it is possible that naturally occurring, chronic, or nonhealing wounds would respond differently.

Interleukin-6 and lactate dehydrogenase expression in a novel ex vivo rocking model of equine corneal epithelial wound healing.

PURPOSE: To establish a physiologically relevant ex vivo model of equine corneal epithelial wound healing. METHODS: Fourteen equine corneas were randomly assigned to one of two groups: wounded (n = 8) or unwounded (n = 6) controls. In the wounded group, the axial corneal epithelium was removed by applying a 6 mm filter paper disk soaked in 1N-NaOH for 60 s. Corneas were subsequently cultured using an air-liquid interface model. Evaluation of corneal healing was performed daily, and culture medium was collected. Corneas were randomly assigned to undergo processing via histopathology and RNAscope in situ hybridization for interleukin-6 (IL-6) and alpha-smooth muscle actin (αSMA) expression at T24, T48, and T72 h after wounding. Media of the cultured corneas were evaluated for the presence of lactate dehydrogenase (LDH) by a colorimetric assay. RESULTS: The ulcerated area of the wounded corneas decreased over time and all corneas healed within 72 h. Histologically, normal corneal architecture was observed including healthy epithelium (in areas other than the ulcerated ones), minimal stromal edema, intact endothelium, and Descemet's membrane. IL-6 expression was increased in wounded corneas compared with unwounded controls. LDH expression was elevated for both wounded and unwounded corneas at T24 but decreased substantially and was not detected at T48 in media from wounded and unwounded corneas, respectively. No αSMA expression was detected from either wounded or unwounded corneas. CONCLUSIONS: The equine air-liquid interface, ex vivo, corneal epithelial wound healing model is effective and physiologically relevant. This model can be used in future studies evaluating various corneal therapies.

Drivers of exit and outcomes for Thoroughbred racehorses participating in the 2017-2018 Australian racing season.

The destinations of Thoroughbred (TB) racehorses exiting the racing industry is a high-profile issue with ethical and welfare implications of interest to both animal welfare groups and racing regulators. This cross-sectional study investigated the reasons that TBs temporarily or permanently exited racing and training in Australia in the 2017-2018 racing season and the outcomes for these horses post-racing. An online questionnaire was sent to the last registered trainers of a representative sample of 2,509 'inactive' TBs. Inactive horses were defined as those horses that were recorded as 'active' but had not trialled or raced in the last 6 months of the racing season or had an inactive status recorded in the Racing Australia database. Of the 1,750 responses received, the largest group of inactive TBs had permanently exited the racing industry (45% retired, 5.3% deceased). A relatively large group exited racing temporarily (43%) but participated in the racing industry in the following season. The reasons for retirement were predominantly voluntary, such as poor performance or owner's request. Almost one third of retirements were due to injuries with tendon or ligament problems the most frequently conditions listed. The median age at retirement was five (Q1 4; Q3 7) years. Extrapolation of the survey results to the population of horses racing or training in Australia in 2017-2018 (n = 37,750) show that that 17% of the population retire each year and 2.1% die. These estimates provide benchmarks for industry and animal welfare organisations to resource and measure the effectiveness of interventions.

Sudden death caused by spinal cord injury associated with vertebral fractures and fetlock failure in a Thoroughbred racehorse.

The most prevalent causes of death in racehorses are musculoskeletal injuries, causing ~83% of deaths within the racing industry in California and elsewhere. The vast majority of these injuries have preexisting lesions that predispose to fatal injury. A 4-y-old Thoroughbred colt suffered an acute suspensory apparatus failure, including biaxial proximal sesamoid bone fractures of the right front fetlock, causing loss of support of the fetlock joint and consequent fall with fractures of the cervical and sacral spine. Cervical fracture caused spinal cord damage that resulted in sudden death. A preexisting lesion in the medial proximal sesamoid bone likely predisposed to complete fracture of this bone and fetlock breakdown. Interestingly, a comparable osteopenic lesion was present in the intact medial proximal sesamoid bone of the left forelimb, which is consistent with bilateral repetitive overuse injury in racehorses. The morphologic features of the cervical and sacral spine fractures were compatible with acute injury; no evidence of preexisting lesions was seen. Most likely, these acute vertebral fractures occurred as a result of the horse falling. This case emphasizes the importance of performing a detailed autopsy in horses that suffer an appendicular musculoskeletal injury, particularly in fatal cases when the horse dies following a leg injury.

The treatment of articular cartilage injuries with mesenchymal stem cells in different animal species.

One of the major problems observed in veterinary practice is articular cartilage injuries in animals. In terms of agriculture, it leads to their culling from the herd, even if they are highly productive animals. With companion animals, owners usually have to decide between euthanasia or long-term sometimes lifelong treatment of the injury by a veterinarian. The use of mesenchymal stem cells (MSCs) for the treatment of cartilage injury in veterinary medicine is based on the good results observed in preclinical studies, where large animals have been used as experimental models to study the regenerative activity of MSCs. According to the literature, MSCs in veterinary medicine have been used to treat cartilage injury of dogs and horses, whereas sheep and goats are generally models for reproducing the disease in preclinical experimental studies.

Modelagem farmacocinética/farmacodinâmica do florfenicol para o tratamento da adenite equina por meio da simulação de Monte Carlo / Pharmacokinetic/pharmacodynamic modeling of florfenicol for the treatment of equine adenitis using Monte Carlo simulation

O objetivo deste trabalho foi avaliar a eficácia do florfenicol na dose usualmente empregada em equinos de 22 mg/kg pelas vias intravenosa, intramuscular e oral para o tratamento de adenite equina por Streptococcus equi. subsp. equi, usando a modelagem farmacocinética/farmacodinâmica (PK/PD – Pharmacokinetic/Pharmacodynamic) e a simulação de Monte Carlo. Foi realizada uma simulação de Monte Carlo a partir dos parâmetros PK, logo depois, efetuou-se a modelagem PK/PD para determinar as taxas de eficácia do antimicrobiano para o tratamento dessa infecção bacteriana, de acordo com o valor da concentração inibitória mínima (CIM), em um intervalo de CIM de 0,125 – 4 μg/mL. Pela via intravenosa, a probabilidade de erradicação bacteriana foi de 100% para CIM até 0,5 μg/mL e efeito bacteriostático com probabilidades de 99% e 80% para CIMs de 2 e 4 μg/mL, respectivamente. Já pelas vias intramuscular e oral a probabilidade de se atingir o índice de erradicação bacteriológica foi de 100% para CIM de até 0,5 μg/mL, contudo, atinge valores de 80% e 81%, respectivamente, para CIM de 1 μg/mL considerando o efeito bactericida (p<0,01). Portanto, através desse estudo é evidenciado a eficácia do florfenicol até a CIM de 0,5 μg/mL para as três vias de administração citadas, entretanto, para CIMs superiores a esse valor, é imprescindível o ajuste da dose farmacológica, evitando falhas na terapêutica e possível resistência microbiana.

The objective of this study was to evaluate the efficacy of florfenicol at the dose usually used in horses of 22 mg/kg by intravenous, intramuscular and oral routes for the treatment of equine adenitis caused by Streptococcus equi. subsp. equi, using Pharmacokinetic/Pharmacodynamic (PK/PD) modeling and Monte Carlo simulation. A Monte Carlo simulation was performed from the PK parameters, then PK/PD modeling was performed to determine the antimicrobial efficacy rates for the treatment of this bacterial infection, according to the minimum inhibitory concentration (MIC) value, in a MIC range of 0.125 - 4 μg/mL. Intravenously, the probability of bacterial eradication was 100% for MICs up to 0.5 μg/mL, and the bacteriostatic effect was 99% and 80% for MICs of 2 and 4 μg/mL, respectively. However, for the intramuscular and oral routes, the probability of reaching the bacteriologic eradication index was 100% for MICs of up to 0.5 μg/mL, however, it reaches values of 80% and 81%, respectively, for MICs of 1 μg/mL considering the bactericidal effect (p<0.01). Therefore, through this study the efficacy of florfenicol is evidenced up to the MIC of 0.5 μg/mL for the three routes of administration cited, however, for MICs higher than this value, it is essential to adjust the pharmacological dose, avoiding failures in therapy and possible microbial resistance.

Ex vivo comparison of standing and recumbent repair of incomplete parasagittal fractures of the first phalanx in horses.

OBJECTIVE: To assess suspensory ligament extensor branch location and fracture gap reduction with simulation of standing and recumbent cortical bone screw repair of experimental incomplete parasagittal proximal phalanx (P1) fractures. STUDY DESIGN: Controlled laboratory study. SAMPLE POPULATION: Twenty equine cadaver forelimbs. METHODS: Simulated fractures were repaired twice in random order. A proximal cortical bone screw was placed in lag fashion with the limb unloaded (simulated recumbent repair) and loaded to 38% of body weight (range, 375-568 kg; simulated standing repair). Changes in fracture gap width were assessed on computed tomography (CT) images and with intraplanar force-sensitive resistors measuring voltage ratios (V△ ) between loaded recumbent (R-1) and standing repair simulations (R-2). Extensor branch borders were determined relative to implant position and sagittal P1 width on transverse CT images. P ≤ .05 was considered significant. RESULTS: Standing repair simulation-associated fracture gaps were not wider than in R-1 while controlling for confounding factors (loading weight, implant position, or animal age; P > .7, repeated-measures analysis of variance). Voltage ratio data associated with R-2 were not smaller than with R-1 (mean difference, 0.002 ± 0.052; one-sided Wilcoxon signed-rank test, P = .27). More of P1 width was approachable palmar to extensor branches when limbs were loaded (0.804 ± 0.314 cm) vs unloaded (0.651 ± 0.31 cm; paired Student's t test, P < .001). CONCLUSION: Simulated standing repair was not associated with inferior fracture reduction compared with loaded simulations of recumbent repairs. Limb loading affected extensor branch location relevant to implant positioning. CLINICAL SIGNIFICANCE: Unloading during standing repair of incomplete parasagittal proximal P1 fractures may not be required to optimize fracture reduction.

Polyaxial pedicle screw external fixation to stabilize oblique mandibular fractures in three standing, sedated horses.

OBJECTIVE: To report the radiographic, surgical and postoperative features in horses with unstable oblique mandibular fractures secured with polyaxial pedicle screws (PPS) external fixation construct and intraoral wiring. ANIMALS: Three client-owned horses. STUDY DESIGN: Short case series. METHODS: Two horses each had a unilateral fracture, which did not improve after conservative management, and one horse had bilateral fractures. Clinical and radiographic features were documented. Polyaxial pedicle screw external fixators and intraoral tension band wiring were applied in standing horses after combining sedation and regional nerve anesthesia. Intraoral wires were implanted through a lateral buccotomy between teeth (two horses) or burred through exposed crown (one horse) and then secured around the incisors. The PPS were inserted under radiographic guidance to avoid tooth roots. Healing was assessed with radiographic examination. The PPS external fixator rod and intraoral wires were removed first. The mandible was manipulated, and, if it was stable, the PPS were removed. RESULTS: Implants were removed at 6, 8, or 10 weeks after the mandibles were palpably stable. Complications included broken wires in one horse, bone sequestration in one horse, and infection in one horse. Follow-up communication with the owners 12 to 18 months later confirmed complete healing without further complications of the fractured mandibles or teeth. CONCLUSION: Polyaxial pedicle screw external fixation led to fracture healing and a return to function in all three horses. The complications encountered did not preclude a successful outcome. CLINICAL SIGNIFICANCE: Polyaxial pedicle screw external fixation coupled with intraoral wiring provides an alternative to treat unstable equine mandibular fractures without general anesthesia.

Avaliação ultrassonográfica dos tendões flexores dos membros anteriores em equinos de vaquejada na microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil / Ultrasound evaluation of the flexor tendons of the forelimbs in horses in vaquejada horses in the Alto Médio Gurgueia, South of Piauí, Brazil

Objetivou-se com este estudo demonstrar a influência do tipo de treinamento sobre as medidas dos tendões flexores palmares em equinos de vaquejada que correm à direita do boi na microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil. Foram utilizados oito animais, da raça quarto de milha e seus mestiços, de diferentes idades, peso e sexo, selecionados e questionados sobre o tempo que exerciam a atividade de vaquejada e o tipo de treinamento a qual eram submetidos, que refere-se a maneira como praticavam a prova correndo de que lado do boi, em uma prova de vaquejada no município de Cristino Castro, Sul do Piauí, Brasil, onde os participantes eram provenientes de diferentes haras da Microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil. Em cada animal foi realizada ultrassonografia das zonas IB, IIB e IIIB dos tendões flexores digital superficial (TFDS) e digital profundo (TFDP), obtendo-se as medidas dos diâmetros médio lateral (DML) e dorso palmar (DDP) através do plano transverso em cada uma das diferentes zonas. Os dados foram submetidos a análise estatística (ANOVA), utilizando-se o teste t a nível de significância de (p<0,05), observando-se que não houve diferença significativa entre as medidas avaliadas. De acordo com os resultados obtidos, cavalos atletas que correm a direita do boi não apresentam diferença significativa nos diâmetros médio lateral e dorso palmar dos tendões flexores entre os antímeros direito e esquerdo do membro torácico.

The objective of this study was to demonstrate the influence of the type of training on the measurements of the palmar flexor tendons in vaquejada horses that run to the right of the ox in the microregion of the Alto Médio Gurgueia, South of Piauí, Brazil. Eight animals of the quarter-mile breed and their crossbreed, of different ages, weight and sex, were selected and asked about the time they were engaged in the activity of the vaquejada and the type of training they were submitted to as they practiced running on which side of the ox, in a vaquejada test in the municipality of Cristino Castro, South of Piauí, Brazil, where the participants came from different farms of the microregion of the Alto Médio Gurgueia, South of Piauí, Brazil. The ultrasonography of the IB, IIB and IIIB zones of the superficial digital (TFDS) and deep digital flexor tendons (TFDP) were performed in each animal, obtaining the measurements of the lateral diameters (DML) and palmar dorsum (DDP) through the transverse plane in each of the different zones. Data were submitted to statistical analysis (ANOVA), using the t test at the significance level of (p <0.05), observing that there was no significant difference between the measures evaluated. According to the results, horses for vaquejada athletes do not present significant difference in the lateral diameters and palmar dorsum of the flexor tendons between the right and left thoracic limb antimeres.

Avaliação ultrassonográfica dos tendões flexores dos membros anteriores em equinos de vaquejada na microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil / Ultrasound evaluation of the flexor tendons of the forelimbs in horses in vaquejada horses in theAlto Médio Gurgueia, South of Piauí, Brazil

Objetivou-se com este estudo demonstrar a influência do tipo de treinamento sobre as medidas dos tendões flexores palmares em equinos de vaquejada que correm à direita do boi na microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil. Foram utilizados oito animais, da raça quarto de milha e seus mestiços, de diferentes idades, peso e sexo, selecionados e questionados sobre o tempo que exerciam a atividade de vaquejada e o tipo de treinamento a qual eram submetidos, que refere-se a maneira como praticavam a prova correndo de que lado do boi, em uma prova de vaquejada no município de Cristino Castro, Sul do Piauí, Brasil, onde os participantes eram provenientes de diferentes haras da Microrregião do Alto Médio Gurgueia, Sul do Piauí, Brasil. Em cada animal foi realizada ultrassonografia das zonas IB, IIB e IIIB dos tendões flexores digital superficial (TFDS) e digital profundo (TFDP), obtendo-se as medidas dos diâmetros médio lateral (DML) e dorso palmar (DDP) através do plano transverso em cada uma das diferentes zonas. Os dados foram submetidos a análise estatística (ANOVA), utilizando-se o teste t a nível de significância de (p<0,05), observando-se que não houve diferença significativa entre as medidas avaliadas. De acordo com os resultados obtidos, cavalos atletas que correm a direita do boi não apresentam diferença significativa nos diâmetros médio lateral e dorso palmar dos tendões flexores entre os antímeros direito e esquerdo do membro torácico.

The objective of this study was to demonstrate the influence of the type of training on the measurements of the palmar flexor tendons in vaquejada horses that run to the right of the ox in the microregion of the Alto Médio Gurgueia, South of Piauí, Brazil. Eight animals of the quarter-mile breed and their crossbreed, of different ages, weight and sex, were selected and asked about the time they were engaged in the activity of the vaquejada and the type of training they were submitted to as they practiced running on which side of the ox, in a vaquejada test in the municipality of Cristino Castro, South of Piauí, Brazil, where the participants came from different farms of the microregion of the Alto Médio Gurgueia, South of Piauí, Brazil. The ultrasonography of the IB, IIB and IIIB zones of the superficial digital (TFDS) and deep digital flexor tendons (TFDP) were performed in each animal, obtaining the measurements of the lateral diameters (DML) and palmar dorsum (DDP) through the transverse plane in each of the different zones. Data were submitted to statistical analysis (ANOVA), using the t test at the significance level of (p <0.05), observing that there was no significant difference between the measures evaluated. According to the results, horses for vaquejada athletes do not present significant difference in the lateral diameters and palmar dorsum of the flexor tendons between the right and left thoracic limb antimeres.

Effect of infrared and red monochromatic light on equine wound healing.

BACKGROUND: Light-emitting diodes (LEDs) are commonly used for treating a variety of disorders in horses, including wounds. Despite its claim to shorten healing times, there is a lack of scientific documentation regarding its effects. OBJECTIVES: To investigate if treatment with pulsating visible red light (λ ≈ 637 nm) and near-infrared (NIR) light (λ ≈ 956 nm) affects wound healing. STUDY DESIGN: Randomised blinded controlled experimental study. METHODS: A circular skin wound (Ø = 2 cm) was created on each side of the neck in eight healthy horses. One randomly chosen wound received light treatment and the other served as an untreated control. Treatment duration was 4 minutes and 40 seconds (red light 95 seconds, 2.3 mW/cm2 ; NIR light 185 seconds, 6.4 mW/cm2 ) and was performed once daily on day 0-4, 7-11, 14-18 and 21-25. The wounds were photographed and evaluated using digital photoplanimetry on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. The degree of swelling was assessed with diagnostic ultrasound on the same days except the last recording was performed on day 36 instead of 35. Days to total healing was recorded. ANOVA was used for statistical analysis (P < .05). RESULTS: The wound area (P = .2-.9) and degree of swelling (P = .2-1.0) did not differ between treated and control groups on any day. There was a significant difference (P = .03) in healing time between control (49.0, 95% CI = 35.4-62.6 days) and treated wounds (51.8, 95% CI = 38.7-64.8 days). MAIN LIMITATIONS: The wounds were treated until day 25 and this study does not investigate the effect of a longer treatment period than 25 days. CONCLUSIONS: The results of this study do not indicate any clinically relevant positive effect of pulsating visible red light and NIR light on the healing of experimental skin wounds in horses, compared with no treatment.

Ex vivo study of vagal branches at risk for iatrogenic injury during laryngoplasty in horses.

OBJECTIVE: To localize vagal branches within the surgical field of laryngoplasty and identify potentially hazardous surgical steps. STUDY DESIGN: Observational cadaveric study. SAMPLE POPULATION: Five equine head-neck specimens and four entire equine cadavers. METHODS: Dissection of the pharyngeal region from a surgical perspective. Neuronal structures were considered at risk if touched or if the distance to instruments was less than 5 mm. RESULTS: The branches of the pharyngeal plexus (PP) supplying the cricopharyngeal muscle (PPcr), the thyropharyngeal muscle (PPth), and the esophagus (PPes) were identified in the surgical field in nine of nine, five of nine, and one of nine specimens, respectively. The internal branch of the cranial laryngeal nerve (ibCLN) was identified within the carotid sheath in six of nine specimens. The external branch of the cranial laryngeal nerve (ebCLN) was identified close to the septum of the caudal constrictors in nine of nine specimens. The blade of the tissue retractor compressed the ibCLN in six of six, the ebCLN in four of six, the PPcr in six of six, the PPth in two of three, and the PPes in two of two specimens in which the respective nerves were identified after further dissection. Surgical exploration of the dorsolateral aspect of the pharynx and the incision of the septum of the caudal constrictors harmed the ebCLN in nine of nine, PPcr in seven of nine, and PPth in four of eight specimens. CONCLUSION: Several vagal branches were located in the surgical field and must be considered at risk because of their location. CLINICAL SIGNIFICANCE: Use of the tissue retractor, dissection over the pharynx, and dissection of the septum of the caudal constrictors involve a risk to damage vagal branches.