The Frequency of Communication Between the Synovial Compartments of the Equine Temporomandibular Joint: A Contrast-Enhanced Computed Tomographic Assessment.

Background: There is conflicting evidence regarding communication between the two compartments of the equine temporomandibular joint (TMJ). Understanding the inter-relationship between TMJ compartments is critical for diagnostic and clinical management purposes. Objective: To determine the frequency of communication between the discotemporal joint (DTJ) and the discomandibular joint (DMJ) of the equine TMJ in horses free of overt disease. Study Design: A randomized, blinded, controlled cadaveric study. Methods: Equine cadaver heads (n = 20), with no reported history of potential TMJ disease, were collected and stored frozen until use. Horses were randomized to the treatment group, such that Group A horses (n = 10) underwent arthrocentesis of the left DTJ and the right DMJ compartments, while Group B (n = 10) underwent arthrocentesis of the left DMJ and the right DTJ compartments of the TMJ, for a total of 40 joints. Computed tomography (CT) imaging was performed before, and after, intra-articular injection of contrast media in each head. Two observers, blinded to the treatment group, independently interpreted CT images. Results: Communication between synovial compartments occurred in the left TMJ of two horses. Arthroscopic evaluation revealed that both horses had a perforation of the intra-articular disc in the region of the caudomedial fibrous expansion. Mild anterior displacement of the abnormal disc in the joint of one horse was demonstrated using magnetic resonance imaging (MRI). Main Limitations: Sample size, the use of owner provided animals' history, and frozen specimens. Conclusions: No physiological communication was present between the DTJ and the DMJ in the equine TMJ of the cases studied, regardless of which compartment underwent arthrocentesis. Two joints had pathological communications. These results suggest that diagnostic, and medical, treatment of intra-articular disease may be most effective when both joint compartments are injected. Furthermore, this study illustrates the value of contrast enhancement while imaging the equine TMJ.

Histologic assessment of age-related changes in the temporomandibular joints of horses.

OBJECTIVE: To describe histologic changes in the temporomandibular joints (TMJs) of horses of various ages. SAMPLE: 22 TMJs from cadavers of 11 horses. PROCEDURES: Horses were categorized into 3 age groups (group 1, 2 to 10 years old [n = 3]; group 2, 11 to 20 years old [3]; and group 3, > 20 years old [5]). Each TMJ was sectioned into 5-mm slices, preserved in formalin, decalcified in formic acid, and routinely processed for histologic analysis. Joints were systematically assessed by use of previously described methods. Multilevel mixed-effects models were used to examine the data. RESULTS: The number of changes was significantly fewer and degree of changes was significantly less within the TMJs of group 1 horses, compared with those of group 3 horses. Comparison among groups revealed that the combination of temporal and mandibular scores for group 1 was significantly lower than for groups 2 or 3. Disk score did not differ significantly between groups 1 and 2, but disk scores of groups 1 and 2 were significantly lower than the disk score of group 3. CONCLUSIONS AND CLINICAL RELEVANCE: The assessed lesions were associated with osteoarthritis, and they accumulated in the TMJs as horses aged. In the absence of signs of pain manifested as changes in mastication, behavior, or performance, it would be difficult to determine the point at which accrued pathological changes represented the onset of clinically important osteoarthritis of the TMJs.

Equine pituitary pars intermedia dysfunction: An international survey of veterinarians' approach to diagnosis, management, and estimated prevalence.

The objectives of the present study were to determine if diagnosis and treatment of equine pituitary pars intermedia dysfunction (PPID) vary by geographic region and to report the prevalence of PPID in horses as observed by veterinarians across locations. An online questionnaire was developed for veterinarians who treat horses. Veterinary associations, especially equine specialty subgroups, were contacted and a survey link was sent to members of each organization. Generalized linear models were used to examine whether the method of diagnosis and treatment of this condition, as well as its reported prevalence, differed by geographic region. Veterinarians from 426 separate clinics in 20 countries returned surveys. Diagnosis of PPID varied by region, but was usually based on clinical signs and an adjunct endocrine test. Horses with PPID were treated medically by 63% of veterinarians and 75% of these used pergolide mesylate as treatment. The median prevalence estimated was 1% and this did not differ by geographic location. Half the veterinarians were caring for 5 or more animals with PPID. Overall, diagnostic approach differed in geographic regions. In general, European veterinarians were more likely than those in North America to diagnose PPID based on clinical signs alone, without using an adjunct laboratory test. Veterinarians reported that cost and management responsibilities were their clients' primary concerns associated with the long-term treatment of this disease, which indicates a need for additional treatment options for PPID.

Les objectifs de la présente étude étaient de déterminer si le diagnostic et le traitement de la dysfonction de l'hypophyse médiale équine (DHME) varient selon la région géographique et signalent la prévalence de la DHME chez les chevaux, comme l'ont observé les vétérinaires dans différentes localisations. Un questionnaire en ligne a été développé pour les vétérinaires qui traitent les chevaux. Les associations vétérinaires, en particulier les sous-groupes de spécialités équines, ont été contactées et un lien pour un sondage a été envoyé aux membres de chaque organisation. Les modèles linéaires généralisés ont été utilisés pour examiner si la méthode de diagnostic et de traitement de cette condition, ainsi que sa prévalence déclarée, différaient selon la région géographique. Les vétérinaires provenant de 426 cliniques distinctes dans 20 pays ont répondu au sondage. Le diagnostic de DHME variait selon la région, mais était généralement basé sur les signes cliniques et un test endocrinien complémentaire. Les chevaux atteints de DHME ont été traités médicalement par 63 % des vétérinaires et 75 % de ceux-ci utilisaient le mésylate de pergolide comme traitement. La prévalence médiane estimée était de 1 % et cela ne différait pas selon la situation géographique. La moitié des vétérinaires prenaient soin de 5 animaux ou plus avec DHME. Dans l'ensemble, l'approche diagnostique différait selon les régions géographiques. En général, les vétérinaires européens étaient plus susceptibles que ceux en Amérique du Nord de diagnostiquer la DHME en se basant uniquement sur les signes cliniques, sans utiliser un test de laboratoire complémentaire. Les vétérinaires ont signalé que les coûts et les responsabilités en matière de gestion étaient les principales préoccupations de leurs clients liées au traitement à long terme de cette maladie, ce qui indique un besoin d'options de traitement supplémentaires pour DHME.(Traduit par Docteur Serge Messier).

In vitro assessment of bacterial translocation during needle insertion through inoculated culture media as a model of arthrocentesis through cellulitic tissue.

OBJECTIVE: To determine by use of an in vitro model the potential for translocating sufficient numbers of bacteria into a joint during arthrocentesis through cellulitic tissue to cause sepsis. SAMPLE: Culture media containing 4 concentrations of Staphylococcus aureus and needles of 3 sizes. PROCEDURES: Needles (22, 20, and 19 gauge) were inserted through Mueller-Hinton agar that contained known concentrations of S aureus (10(3),10(4),10(5), and 10(6) CFUs/mL). After a needle exited through the medium, any agar plug within the needle bore was ejected into a sterile syringe and the contaminated portion of the needle was harvested. Sterile saline (0.9% NaCl) solution was used to emulsify the agar plug and wash the contaminated portion of the needle. The resulting solution was cultured to determine the number of bacterial CFUs that could be deposited into a joint during arthrocentesis through contaminated tissue. RESULTS: Needle gauge and bacterial concentration were both associated with the number of bacterial CFUs deposited after insertion through contaminated agar. Although all needle sizes were capable of bacterial translocation sufficient to cause septic arthritis, ORs for 20- and 22-gauge needles translocating > 33 CFUs of S aureus were significantly higher than the OR for a 19-gauge needle. The ORs for 20- or 22-gauge needles translocating > 33 CFUs of S aureus (the minimum population of S aureus known to cause joint sepsis) were 0.22. CONCLUSIONS AND CLINICAL RELEVANCE: Results for this in vitro model indicated that caution should be used when performing arthrocentesis through cellulitic tissue.