Comparison of treatments for equine laryngeal hemiplegia using computational fluid dynamic analysis in an equine head model.

Introduction: Computational fluid dynamics (CFD) is gaining momentum as a useful mechanism for analyzing obstructive disorders and surgeries in humans and warrants further development for application in equine surgery. While advancements in procedures continue, much remains unknown about the specific impact that different surgeries have on obstructive airway disorders. The objective of this study was to apply CFD analysis to an equine head inhalation model replicating recurrent laryngeal neuropathy (RLN) and four surgical procedures.

Contrast arthrography of the equine temporomandibular joint.

Background: Disorders of the equine temporomandibular joint (TMJ) cause clinical problems and detailed investigations of this joint are becoming more common. Specialist radiographic projections have the potential to highlight osseous abnormalities; however, the ability to assess the intra-articular soft tissue structures is currently limited to computed tomography (with, or without contrast enhancement) or magnetic resonance imaging. Both modalities are expensive and not readily accessible.

Equine poor performance: the logical, progressive, diagnostic approach to determining the role of the temporomandibular joint.

Poor performance is an ambiguous term used frequently by people in the horse industry. It means different things to different people, depending on the breed, discipline, or problem being discussed. There are myriad reasons that a horse may fail to achieve the expectations put upon it or, having achieved those goals, begin to falter.

The effect of acute equine temporomandibular joint inflammation on response to rein-tension and kinematics.

Background: Although the temporomandibular joint (TMJ) is the major contact point between the reins in the riders' hand, the bit in the mouth, and the rest of the horse under saddle, the role of inflammation of this joint on equine locomotion and rein tension is unknown.

Objective: To determine the effect of acute TMJ inflammation on rein-tension and horse movement when horses were long-reined on a treadmill.

Study Design: A randomized, controlled, cross-over design.

Computational fluid dynamic analysis of upper airway procedures in equine larynges.

Introduction: Computational fluid dynamics (CFD) has proven useful in the planning of upper airway surgery in humans, where it is used to anticipate the influence of the surgical procedures on post-operative airflow. This technology has only been reported twice in an equine model, with a limited scope of airflow mechanics situations examined. The reported study sought to widen this application to the variety of procedures used to treat equine recurrent laryngeal neuropathy (RLN).

A biomechanical comparison of a novel two-loop suture technique and two sutures for laryngoplasty in the horse.

Objectives: Evaluation of the strength of the novel suture technique by comparison with a 2-interrupted suture technique.

Sample: 40 equine larynges.

Procedures: 40 larynges were used; 16 laryngoplasties were performed using the currently accepted 2-suture technique and 16 using the novel suture technique.

A Retrospective Observational Cohort Study on the Expiration of Maxillary Cheek Teeth Infundibula in 217 Horses.

The determination of a horse's age by its dentition is a technique that has been employed by horse owners and professionals since at least 600 BC. While aging teeth based on incisor wear patterns is common, wear patterns in the cheek teeth may also be useful. As horses continue to live longer, we routinely examine horses into their 20's and 30's, and it is becoming more common to observe aging changes in the cheek teeth.

Long-Term Outcome of Horses Undergoing Unilateral Mandibular Condylectomy and Meniscectomy for Temporomandibular Joint Disease.

Background: There are no reports describing the long-term outcome of sport horses undergoing unilateral mandibular condylectomy with meniscectomy (UMC) for treatment for severe temporomandibular joint (TMJ) disease (TMD). Whether horses undergoing UMC require a specialized diet, can return to riding with a bit, or return to intended function after surgery is unknown.

Objective: To determine the long-term outcome of horses undergoing UMC for treatment of severe TMD.

The Equine Temporomandibular Joint: Comparisons Between Standard and Needle Arthroscopic Examination of Cadaver Specimens and Standing Horses.

Background: Definitive diagnosis of equine temporomandibular joint osteoarthritis (TMJ-OA) may require advanced diagnostic imaging. Arthroscopy is a modern, minimally invasive, diagnostic, and treatment modality. Standing arthroscopic treatment of joint disease is a relatively recent advance in equine surgery, despite which there are few published comparisons between the available arthroscopic systems.

X-ray tube operators can be exposed to equal or higher scattered radiation doses to the hand as cassette holders during diagnostic radiographic procedures of the equine vertebral column and limbs.

Objective: The objectives of this study were to investigate scattered radiation doses to the hands of equine workers holding the cassette and the x-ray tube by hand, for both limb and vertebral column studies, and to compare the scattered radiation attenuation of lead with radiation protection lead-free gloves. Radiation doses to the hands of the cassette holder in the primary beam were also investigated.

Sample: A whole-body horse cadaver.

Computed tomographic geometrical analysis of surgical treatments for equine recurrent laryngeal neuropathy.

Objectives: To characterize the 3-D geometry of the equine larynx replicating laryngeal hemiplegia and 4 surgical interventions by use of CT under steady-state airflow conditions. Secondly, to use fluid mechanic principles of flow through a constriction to establish the relationship between measured airflow geometries with impedance for each surgical procedure.

Sample: 10 cadaveric horse larynges.

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

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. 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.

cAMP triggers Na absorption by distal airway surface epithelium in cystic fibrosis swine.

A controversial hypothesis pertaining to cystic fibrosis (CF) lung disease is that the CF transmembrane conductance regulator (CFTR) channel fails to inhibit the epithelial Na channel (ENaC), yielding increased Na reabsorption and airway dehydration. We use a non-invasive self-referencing Na-selective microelectrode technique to measure Na transport across individual folds of distal airway surface epithelium preparations from CFTR (CF) and wild-type (WT) swine. We show that, under unstimulated control conditions, WT and CF epithelia exhibit similar, low rates of Na transport that are unaffected by the ENaC blocker amiloride.

Survey of self-reported radiation safety practices among North American veterinary technicians involved in equine radiography using portable x-ray equipment.

Objectives: To describe self-reported radiation safety practices by equine veterinary technicians in North America and identify factors associated with these practices.

Sample: 154 equine technicians.

Procedures: An electronic questionnaire regarding radiation safety practices during the use of portable x-ray equipment was sent to 884 members of the American Association of Equine Veterinary Technicians and Assistants.

Radiation safety practices among Canadian equine veterinary workers during diagnostic procedures with portable X-ray equipment.

The objective of this study was to report observed radiation safety practices among equine workers using portable X-ray units at 3 veterinary practices in Canada. Practice 1 was comprised of equine field service workers from an academic institution, whereas Practices 2 and 3 were comprised of workers from private equine referral practices. Out of 2969 exposure-worker observations, protective aprons were worn for > 99% (2968/2969), thyroid shields for 87% (2584/2969), and eyeglasses for 10% (310/2969).

Arthroscopic approach and intra-articular anatomy of the equine discomandibular joint compartment of the temporomandibular joint.

Objective: To develop an arthroscopic approach to the discomandibular joint (DMJ), the ventral compartment of the temporomandibular joint (TMJ) of the horse.

Study Design: Experimental study.

Sample Population: Nine cadaveric equine heads and two live horses.

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]).

Ex vivo evaluation of arytenoid corniculectomy, compared with three other airway interventions, performed on cadaveric equine larynges with simulated recurrent laryngeal neuropathy.

Objective: To compare laryngeal impedance, in terms of air flow and pressure, following arytenoid corniculectomy (COR) versus 3 other airway interventions (left-sided laryngoplasty with ipsilateral ventriculocordectomy [LLP], LLP combined with COR [LLPCOR], and partial arytenoidectomy [PA]) performed on cadaveric equine larynges with simulated left recurrent laryngeal neuropathy (RLN) and to determine whether relative laryngeal collapse correlated with the interventions performed.

Sample: 28 cadaveric equine larynges.

Procedures: Each larynx in states of simulated left RLN alone and with airway interventions in the order LLP, LLPCOR, COR, and PA was evaluated in a box model construct that replicated upper airway flow mechanics consistent with peak exercise in horses.

Novel technique for prevention of rotation of the distal phalanx relative to the hoof wall in horses with acute laminitis.

Objective: To determine the holding capacity of a 5.5-mm-diameter cortical bone screw when placed in the third phalanx (P3) of horses and assess whether screw placement through the dorsal hoof wall into P3 would be tolerated by clinically normal horses and would alleviate signs of pain and prevent P3 rotation in horses with oligofructose-induced laminitis.

Animals: 40 limbs from 10 equine cadavers and 19 clinically normal adult horses.

In vitro mechanical evaluation of three transfixation pin-cast constructs applied to equine forelimbs.

OBJECTIVE To compare strain at the bone-pin and cast-pin interfaces among 3 transfixation pin-cast constructs applied to equine forelimbs. ANIMALS 15 forelimbs from 15 adult horses. PROCEDURES Limbs were randomly assigned to 1 of 3 constructs.

Use of crown height of the maxillary first molar tooth to approximate the age of horses.

OBJECTIVE To identify whether age, sex, or breed is associated with crown height of the left and right maxillary first molar tooth (M1) measured on CT images, to develop a mathematical model to determine age of horses by use of M1 crown height, and to determine the correlation between M1 crown height measured on radiographic and CT images. SAMPLE CT (n = 735) and radiographic images (35) of the heads of horses. PROCEDURES Crown height of left and right M1 was digitally measured on axial CT views.

Profiles of pro-opiomelanocortin and encoded peptides, and their processing enzymes in equine pituitary pars intermedia dysfunction.

Equine pituitary pars intermedia dysfunction (PPID) is characterized by hyperplasia of the pars intermedia (PI) melanotrophs of the pituitary gland (PG), and increased production of proopiomelanocortin (POMC). POMC is cleaved by prohormone convertase 1 (PC1) to produce adrenocorticotropic hormone (ACTH), and further processing of ACTH by PC2 to produce alpha-melanocyte stimulating hormone (α-MSH) and corticotropin-like intermediate peptide (CLIP). High plasma ACTH concentrations in horses with PPID might be related to reduced conversion of ACTH to α-MSH by PCs.

Development of two surgical approaches to the pituitary gland in the Horse.

Background: Current treatment of equine pituitary pars intermedia dysfunction (PPID) requires daily oral medication. Minimally invasive surgical palliation of this condition is appealing as a single treatment to alleviate the clinical signs of disease, dramatically improving the welfare of the horse.

Objective: To develop a surgical approach to the equine pituitary gland, for subsequent treatment of PPID.

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.

Cystic fibrosis swine fail to secrete airway surface liquid in response to inhalation of pathogens.

Cystic fibrosis is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) channel, which can result in chronic lung disease. The sequence of events leading to lung disease is not fully understood but recent data show that the critical pathogenic event is the loss of the ability to clear bacteria due to abnormal airway surface liquid secretion (ASL). However, whether the inhalation of bacteria triggers ASL secretion and whether this is abnormal in cystic fibrosis has never been tested.