Targeted multifidus muscle activation reduces fibrosis of multifidus muscle following intervertebral disc injury.

PURPOSE: Aerobic exercise produces beneficial outcomes in patients with low back pain and partially attenuates the fibrotic changes to the multifidus in a model of intervertebral disc (IVD) degeneration. More targeted exercise might be required to fully attenuate these fibrotic alterations. This study aimed to investigate whether activation of the multifidus induced by neurostimulation could reduce fibrosis of the multifidus in a model of IVD degeneration in sheep. METHODS: IVD degeneration was induced in 18 merino sheep via a partial thickness unilateral annulus fibrosus lesion to the L1/2 and L3/4 IVDs. All sheep received an implantable neurostimulation device that provides stimulation of the L2 medial branch of the dorsal ramus. Three months after surgery, the animals were assigned to Injury or Activated groups. Activated animals received neurostimulation and the Injury group received no stimulation. Six months after surgery, the multifidus was harvested at L2 and L4. Van Gieson's, Sirius Red and immunofluorescence staining for Collagen-I and -III and quantitative PCR was used to examine fibrosis. Muscle harvested from a previous study without IVD injury was used as a control. RESULTS: Neurostimulation of the multifidus attenuated IVD degeneration dependent increases in the connective tissue, including Collagen-I but not Collagen-III, compared to the Injury group at L4. No measures of the multifidus muscle at L2, which received no stimulation, differed between the Injury and Activated groups. CONCLUSIONS: These data reveal that targeted activation of the multifidus muscle attenuates IVD degeneration dependent fibrotic alterations to the multifidus.

Stakeholder perceptions of thoroughbred yearling sales endoscopy in Australia: can we do better?

OBJECTIVE: To identify thoroughbred industry stakeholders' views on the yearling sales endoscopy in Australia. DESIGN: Semi-structured qualitative group interviews with equine veterinarians, thoroughbred breeders and yearling purchasers. METHODS: Twenty-nine experienced thoroughbred industry stakeholders participated in online focus groups: (1) equine veterinarians involved in yearling endoscopy; (2) thoroughbred breeders; and (3) yearling buyers. The focus groups were audio and video recorded and digital whiteboards were available. Data was transcribed, live-coded and analysed thematically. RESULTS: The main themes identified included the uncertainty surrounding the relationship between yearling laryngeal function and future performance, especially the significance of yearlings with grade 3 out of 5 laryngeal function; interobserver variability in the laryngeal function grade assigned by veterinarians to the same endoscopic exam; and the presence of intra-horse variability in laryngeal function over different time points. DISCUSSION: Stakeholders raised multiple concerns about the current yearling sales endoscopy process in Australia. Recommendations to address these concerns include further investigation into the race performance of yearlings identified with grade 3 laryngeal function; training of veterinarians to reduce inter-observer variability; and the need to determine the most appropriate grading system to use in yearlings. Future research should evaluate the significance of intra-horse variability in a yearling population.

Evaluation of postsale endoscopy as a predictor of future racing performance in an Australian thoroughbred yearling population.

INTRODUCTION: Upper airway endoscopy of thoroughbred (TB) yearlings is commonly used in an attempt to predict laryngeal function (LF) and its impact on future race performance. The aim of this study was to determine if different grading systems and laryngeal grades were correlated with future performance. MATERIALS AND METHODS: Postsale endoscopic recordings were obtained from an Australian TB yearling sale during a four-year period from 2008 to 2011. Horses were included if they had a diagnostic postsale video endoscopic recording and raced within Australia. Recordings were graded using the Havemeyer system and subsequently recategorised according to the Lane scale and two condensed scales. Performance data were sourced from Racing Australia and comparisons were made between groups. RESULTS: A total of 1244 horses met the inclusion criteria. There were no significant differences in sex or sales price between groups. There were no significant differences in the number of starts or wins between groups for any grading system. For the condensed Havemeyer scale, horses with intermediate LF were separated into two groups. Significant differences in earnings were found between 'normal' and 'abnormal' (P = 0.02) and 'intermediate-low' and 'abnormal' grades (P = 0.03). There were no significant differences between horses with 'intermediate-high' and 'abnormal' grades (P = 0.40). No significant differences were found between the two intermediate grades (P = 0.60) or between horses with normal LF and either 'intermediate-low' or 'intermediate-high' grades (P = 0.99). DISCUSSION: Resting LF in Australian yearling TBs assessed using a condensed Havemeyer grading scale had some predictive value for future racing performance. This information should be considered when performing yearling endoscopic examinations.

Antifungal non-invasive soak under general anaesthetic to treat fungal rhinitis in an Australian Quarter Horse gelding at pasture.

BACKGROUND: Mycotic rhinitis is a rare disease in horses, with few cases reported worldwide and none reported in Australia. Fungal infection of the upper respiratory tract can occur in all species, but its prevalence in horses is considerably lower than in canines or humans. The disease is linked to a variety of pathogens and the clinical signs are associated with subsequent upper respiratory tract damage. CASE REPORT: A 6-year-old Quarter Horse gelding in Queensland, Australia, was presented with chronic nasal discharge and dyspnoea following previous unsuccessful medical treatment of 9 months' duration. Culture yielded a mixed growth of Cryptococcus and Rhodotorula, as well as secondary bacterial species. The horse was anaesthetised and positioned in sternal recumbency. The nasal passages and sinuses were bathed with fluconazole and dimethylsulfoxide for 1 h on two separate occasions 4 weeks apart. Systemic antimicrobials and corticosteroids were also administered for brief courses. Endoscopic examination 4 months after treatment demonstrated clinical resolution of the rhinitis with residual scar tissue. Owners reported resolution of clinical signs and following the treatment the gelding was able to perform athletically. CLINICAL RELEVANCE: Mycotic rhinitis is an unusual disease that can be difficult to treat successfully. This report describes a technique for topical sinonasal bathing under general anaesthetic that was well tolerated, easy to perform and resulted in a successful clinical outcome.

Comparison of conventional radiography and computed tomography as aids in the diagnosis of osteomyelitis in 11 foals.

BACKGROUND: Conventional radiography is currently the most common imaging modality used by veterinarians investigating foals with suspected osteomyelitis. Emerging evidence in adult horses and humans suggests computed tomography (CT) is a superior modality for evaluation of osseous changes in general. This study aimed to evaluate the potential benefits of CT versus conventional radiography in cases of osteomyelitis in foals. METHODS: Cases of osteomyelitis in foals under 6 months of age admitted over a 6-year period at a single referral hospital that had both CT and conventional radiography images were retrieved. Case details and measurements of the largest area of bone lysis identified in two planes (lateromedial/sagittal and dorsopalmar/dorsal) were evaluated by three veterinarians with a range of experience. RESULTS: A significant difference regarding lesion size was seen on the lateromedial (LM) radiographic projections compared with the equivalent sagittal plane CT image. The LM radiographic evaluation resulted in a 37% underestimation of the area of the lesion. Additionally, use of the LM radiographic projections were 2.5-fold more variable in the measurement area compared with CT. In general, regardless of projection, CT produced more information regarding lesion area and, in some cases, detected osseous changes that were not evident on the radiographs. CLINICAL RELEVANCE: LM radiographic projections are less reliable and commonly result in an under-appreciation of lesion size and extent. CT detected lesions that were difficult or impossible to identify on radiographs and may allow improved treatment planning.

Overground endoscopy in 311 Thoroughbred racehorses: findings and correlation to resting laryngeal function.

OBJECTIVE: To review a large number of equine overground endoscopy (OGE) examinations to determine the incidence of dynamic upper airway obstructions (DUAO); correlations were explored with laryngeal endoscopy findings at rest and abnormal exercising respiratory noise. METHODS: Retrospective analysis of horses presenting for OGE because of perceived poor performance and/or history of abnormal exercising respiratory noise between 2010 and 2014. Signalment, history and examination findings during resting laryngeal endoscopy and OGE were reviewed. RESULTS: Of the total examinations, 311 were reviewed. One or more DUAO were found in 249/311 horses. From 210 males (colts and geldings), 121 had arytenoid cartilage collapse (ACC) and 111 had vocal fold collapse (VFC). From 101 females, 25 had intermittent dorsal displacement of the soft palate (DDSP). Resting laryngeal function grade 4 was found in 121/311 of the study population and 92/210 of males. An association was found between horses with lower resting arytenoid abduction ability to dynamic ACC and higher resting arytenoid abduction ability with DDSP. Abnormal exercising respiratory noise was positively associated with the presence of DUAO. CONCLUSIONS: Multiple DUAO in association with abnormal exercising respiratory noise was a common finding in horses examined for poor performance. This study highlights the importance of OGE in accurately diagnosing the nature of DUAO associated with poor performance.

Maxillary unicystic ameloblastoma in a 6-week-old filly evaluated with computed tomography.

CASE REPORT: A 6-week-old Thoroughbred filly was presented for evaluation of an expansile mass overlying the right nasal passage and causing respiratory stertor. On skull radiographs, there was a loculated, soft tissue-opaque mass identified dorsal to the right upper premolars and effacing the right nasal cavity. Computed tomography (CT) revealed a locally extensive mass with relatively benign characteristics located centrally on the tooth root apices of the deciduous second premolar (506). The mass extended axially into the right nasal cavity, occluding the meatuses and causing displacement of the nasal septum to the left. CLINICAL OUTCOME & SIGNIFICANCE: Surgical excision was not deemed feasible with an athletic future in mind and the owners elected to euthanase the filly. Histopathologically, the mass was consistent with unicystic ameloblastoma and was lined intermittently with palisading, columnar basal cells (ameloblast-like cells) overlying a zone containing stellate cells in loose stroma. To the authors' knowledge this is the first report of a CT scan of an equine ameloblastoma. Although histopathology was essential for definitive diagnosis, CT clearly defined the origin of the mass and identified its locally extensive, cystic nature, which enabled informed decisions to be made.

Supraglenoid tubercle fractures repair with transverse locking compression plates in 4 horses.

OBJECTIVE: To report on a series of 4 horses with supraglenoid tubercle fractures repaired with locking compression plates. STUDY DESIGN: Case series. ANIMAL: Four horses ranging in age from 6 weeks to 20 months and weighing from 121 to 425 kg with supraglenoid tubercle fractures of 1 day to 6 weeks in duration. METHODS: Supraglenoid tubercle fractures were reduced and stabilized with transversely positioned locking compression plate(s) with and without additional tension band wiring. RESULTS: All fractures reached bony union. Two postoperative surgical site infections were managed with drainage and antibiotherapy. Three of the 4 horses continued onto athletic careers including flat racing, dressage, and hunter/jumper competition. The remaining horse was lame for a prolonged period, but was sound at 4 years. CONCLUSIONS: The application of one or two, transversely positioned LCPs should be considered for the repair of SGT fractures because of the relative ease of the technique, and its elimination of a biceps brachii tenotomy. All screws can be inserted in a lateral to medial direction without transection or drill penetration of the biceps brachii tendon. CLINICAL RELEVANCE: SGT fractures of various durations can be repaired in a wide range of horses with transversely positioned LCPs, and allow return to athletic function.

Association of tracheal mucus or blood and airway neutrophilia with racing performance in Thoroughbred horses in an Australian racing yard.

OBJECTIVES: To determine the variation of tracheal mucus scores, tracheal blood scores and transendoscopic tracheal wash (TW) cytology in a population of Thoroughbred (TB) racehorses and assess their association with racing performance. METHODS: A total of 220 endoscopic examinations were performed and TWs obtained from 155 TB racehorses. Samples were collected 60-120 min following gallop work. Tracheal mucus score, tracheal blood score and TW cytology were analysed and their association with racing performance assessed. RESULTS: Of the total examinations and samples, 194 from 135 horses fitted the criteria for inclusion. The overall prevalence of visible tracheal mucus was 2.5% (5/194) and of increased tracheal mucus was 0%. The prevalence of visible tracheal blood was 8.8% (17/194) and of increased tracheal blood was 4.6% (9/194). A total of 36% (70/194) of TWs contained elevated percentages of neutrophils and of these, 96% (67/70) occurred in the absence of any visible tracheal mucus. There was no significant association between tracheal mucus score or TW cytology and subsequent racing performance. There was a statistically significant association (P = 0.004) between increased tracheal blood scores and poor racing performance. CONCLUSIONS: Visible tracheal blood seen after strenuous exercise in clinically normal TB racehorses was a risk factor for poor racing performance, but the presence of airway neutrophilia was not. No horses in this study were found to have increased tracheal mucus, so the association of increased tracheal mucus with racing performance could not be assessed.

Preclinical animal models in single site cartilage defect testing: a systematic review.

OBJECTIVE: Review the literature for single site cartilage defect research and evaluate the respective strengths and weaknesses of different preclinical animal models. METHOD: A literature search for animal models evaluating single site cartilage defects was performed. Variables tabulated and analyzed included animal species, age and number, defect depth and diameter and study duration. Cluster analyses were then used to separate animals with only distal femoral defects into similar groups based on defect dimensions. Representative human studies were included allowing comparison of common clinical lesions to animal models. The suitability of each species for single site cartilage defect research and its relevance to clinical human practice is then discussed. RESULTS: One hundred thirteen studies relating to single site cartilage defects were reviewed. Cluster analysis included 101 studies and placed the murine, laprine, ovine, canine, porcine and caprine models in group 1. Group 2 contained ovine, canine, porcine, caprine and equine models. Group 3 contained only equine models and humans. Species in each group are similar with regard to defect dimensions. Some species occur in multiple groups reflecting utilization of a variety defect sizes. We report and discuss factors to be considered when selecting a preclinical animal model for single site cartilage defect research. DISCUSSION: Standardization of study design and outcome parameters would help to compare different studies evaluating various novel therapeutic concepts. Comparison to the human clinical counterpart during study design may help increase the predictive value of preclinical research using animal models and improve the process of developing efficacious therapies.