Computed tomography of the equine temporohyoid joint: Association between imaging changes and potential risk factors.

Background: Temporohyoid osteoarthropathy (THO) is characterised by bone proliferation and cartilage ossification caused by infectious and degenerative conditions, amongst others.

Objectives: To describe the variable appearance of the temporohyoid joint (THJ) on computed tomography (CT) and investigate associations between CT changes and potential risk factors.

Study Design: Cross-sectional study.

Stimulation of the internal superior laryngeal nerve as a potential therapy for obstructive sleep apnea in a porcine model.

Impaired pharyngeal sensing of negative pressure (NP) can lead to a blunted response of the upper airway dilator muscles and contribute to the development of obstructive sleep apnea (OSA). This response is modulated by the nerve fibers in the internal branch of the superior laryngeal nerve (iSLN), mediating negative pressure sensation. Artificial excitation of these fibers could be a potential treatment target for OSA.

Bilateral Functional Electrical Stimulation for the Treatment of Presbyphonia in a Sheep Model.

Objectives: The aim of the study was to increase muscle volume and improve phonation characteristics of the aged ovine larynx by functional electrical stimulation (FES) using a minimally invasive surgical procedure.

Methods: Stimulation electrodes were placed bilaterally near the terminal adduction branch of the recurrent laryngeal nerves (RLN). The electrodes were connected to battery powered pulse generators implanted subcutaneously at the neck region.

A method to identify, dissect and stain equine neuromuscular junctions for morphological analysis.

Morphological study of the neuromuscular junction (NMJ), a specialised peripheral synapse formed between a lower motor neuron and skeletal muscle fibre, has significantly contributed to the understanding of synaptic biology and neuromuscular disease pathogenesis. Rodent NMJs are readily accessible, and research into conditions such as amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy (SMA) has relied heavily on experimental work in these small mammals. However, given that nerve length dependency is an important feature of many peripheral neuropathies, these rodent models have clear shortcomings; large animal models might be preferable, but their size presents novel anatomical challenges.

Overcoming temporal dispersion for measurement of activity-related impedance changes in unmyelinated nerves.

Fast neural electrical impedance tomography is an imaging technique that has been successful in visualising electrically evoked activity of myelinated fibres in peripheral nerves by measurement of the impedance changes (dZ) accompanying excitation. However, imaging of unmyelinated fibres is challenging due to temporal dispersion (TP) which occurs due to variability in conduction velocities of the fibres and leads to a decrease of the signal below the noise with distance from the stimulus. To overcome TP and allow electrical impedance tomography imaging in unmyelinated nerves, a new experimental and signal processing paradigm is required allowing dZ measurement further from the site of stimulation than compound neural activity is visible.

Ex vivo biomechanical evaluation of polyester and polyblend suture techniques to perform equine laryngoplasty.

Objective: To validate the use of a polyblend tape suture in equine laryngoplasty (PL).

Study Design: Experimental study.

Animals: Thirty-two cadaveric larynges.

Human-relevant near-organ neuromodulation of the immune system via the splenic nerve.

Neuromodulation of immune function by stimulating the autonomic connections to the spleen has been demonstrated in rodent models. Consequently, neuroimmune modulation has been proposed as a new therapeutic strategy for the treatment of inflammatory conditions. However, demonstration of the translation of these immunomodulatory mechanisms in anatomically and physiologically relevant models is still lacking.

Splenic Nerve Neuromodulation Reduces Inflammation and Promotes Resolution in Chronically Implanted Pigs.

Neuromodulation of the immune system has been proposed as a novel therapeutic strategy for the treatment of inflammatory conditions. We recently demonstrated that stimulation of near-organ autonomic nerves to the spleen can be harnessed to modulate the inflammatory response in an anesthetized pig model. The development of neuromodulation therapy for the clinic requires chronic efficacy and safety testing in a large animal model.

Imaging of focal seizures with Electrical Impedance Tomography and depth electrodes in real time.

Intracranial EEG is the current gold standard technique for localizing seizures for surgery, but it can be insensitive to tangential dipole or distant sources. Electrical Impedance Tomography (EIT) offers a novel method to improve coverage and seizure onset localization. The feasibility of EIT has been previously assessed in a computer simulation, which revealed an improved accuracy of seizure detection with EIT compared to intracranial EEG.

Thyrohyoideus muscle innervation in the horse.

Objective: To describe the innervation of the thyrohyoideus (TH) muscle and to confirm our findings with stimulation of first cervical (C1) nerve branches.

Study Design: Ex vivo phase 1 and clinical phase 2.

Animals: Fourteen head and neck specimens and 17 client-owned horses.

Ex vivo modeling of the airflow dynamics and two-and three-dimensional biomechanical effects of suture placements for prosthetic laryngoplasty in horses.

Objective: To identify the degree of left arytenoid cartilage (LAC) abduction that allows laryngeal airflow similar to that in galloping horses, assess 2-D and 3-D biomechanical effects of prosthetic laryngoplasty on LAC movement and airflow, and determine the influence of suture position through the muscular process of the arytenoid cartilage (MPA) on these variables.

Sample: 7 equine cadaver larynges.

Procedures: With the right arytenoid cartilage maximally abducted and inspiratory airflow simulated by vacuum, laryngeal airflow and translaryngeal pressure and impedance were measured at 12 incremental LAC abduction forces (0% to 100% [maximum abduction]) applied through laryngoplasty sutures passed caudocranially or mediolaterally through the left MPA.

Feasibility of kilohertz frequency alternating current neuromodulation of carotid sinus nerve activity in the pig.

Recent research supports that over-activation of the carotid body plays a key role in metabolic diseases like type 2 diabetes. Supressing carotid body signalling through carotid sinus nerve (CSN) modulation may offer a therapeutic approach for treating such diseases. Here we anatomically and histologically characterised the CSN in the farm pig as a recommended path to translational medicine.

Investigation into pathophysiology of naturally occurring palatal instability and intermittent dorsal displacement of the soft palate (DDSP) in racehorses: Thyro-hyoid muscles fatigue during exercise.

Exercise induced intermittent dorsal displacement of the soft palate (DDSP) is a common cause of airway obstruction and poor performance in racehorses. The definite etiology is still unclear, but through an experimental model, a role in the development of this condition was identified in the dysfunction of the thyro-hyoid muscles. The present study aimed to elucidate the nature of this dysfunction by investigating the spontaneous response to exercise of the thyro-hyoid muscles in racehorses with naturally occurring DDSP.

Electrode fabrication and interface optimization for imaging of evoked peripheral nervous system activity with electrical impedance tomography (EIT).

Objective: Non-invasive imaging techniques are undoubtedly the ideal methods for continuous monitoring of neural activity. One such method, fast neural electrical impedance tomography (EIT) has been developed over the past decade in order to image neural action potentials with non-penetrating electrode arrays.

Approach: The goal of this study is two-fold.

Functional Electrical Stimulation Leads to Increased Volume of the Aged Thyroarytenoid Muscle.

Objectives/hypothesis: To reverse sarcopenia and increase the volumes of atrophied laryngeal muscles by functional electrical stimulation (FES) using a minimal invasive surgical procedure in an aged ovine model.

Study Design: Prospective animal study.

Methods: A stimulation electrode was placed unilaterally near the terminal adduction branch of the recurrent laryngeal nerve (RLN) adjacent to the right cricothyroid joint.

Anatomy of the vestibulum esophagi and surgical implications during prosthetic laryngoplasty in horses.

Objective: To describe the anatomy of the entry to the equine esophagus (vestibulum esophagi) and to assess the risk of penetrating its adventitia and/or lumen during laryngoplasty.

Study Design: Ex vivo cadaveric study.

Sample Population: Five isolated equine larynges and 39 equine head and neck specimens.

Ex vivo biomechanical stability of 5 cricoid-suture constructs for equine laryngoplasty.

Objective: To determine the biomechanical properties of 5 suture constructs in the equine cricoid under cyclic loading and load to failure testing.

Study Design: Ex vivo study.

Samples: Seventy-five equine cadaver larynges.

Correction: Reversing Age Related Changes of the Laryngeal Muscles by Chronic Electrostimulation of the Recurrent Laryngeal Nerve.

[This corrects the article DOI: 10.1371/journal.pone.

Reversing Age Related Changes of the Laryngeal Muscles by Chronic Electrostimulation of the Recurrent Laryngeal Nerve.

Age related atrophy of the laryngeal muscles -mainly the thyroarytenoid muscle (TAM)- leads to a glottal gap and consequently to a hoarse and dysphonic voice that significantly affects quality of life. The aim of our study was to reverse this atrophy by inducing muscular hypertrophy by unilateral functional electrical stimulation (FES) of the recurrent laryngeal nerve (RLN) in a large animal model using aged sheep (n = 5). Suitable stimulation parameters were determined by fatiguing experiments of the thyroarytenoid muscle in an acute trial.

Feasibility, repeatability, and safety of ultrasound-guided stimulation of the first cervical nerve at the alar foramen in horses.

OBJECTIVE To develop and assess the feasibility, repeatability, and safety of an ultrasound-guided technique to stimulate the first cervical nerve (FCN) at the level of the alar foramen of the atlas of horses. ANIMALS 4 equine cadavers and 6 clinically normal Standardbreds. PROCEDURES In each cadaver, the FCN pathway was determined by dissection, and any anastomosis between the first and second cervical nerves was identified.

Effects of Functional Electrical Stimulation on Denervated Laryngeal Muscle in a Large Animal Model.

Bilateral vocal fold paralysis (BVCP) is a life-threatening condition that follows injury to the Recurrent Laryngeal nerve (RLn) and denervation of the intrinsic laryngeal musculature. Functional electrical stimulation (FES) enables restoration and control of a wide variety of motor functions impaired by lower motor neuron lesions. Here we evaluate the effects of FES on the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle in a large animal model of RLn injury.

In vitro effect of ventriculocordectomy before laryngoplasty on abduction of the equine arytenoid cartilage.

Objective: To determine whether ventriculocordectomy (VCE) performed before prosthetic laryngoplasty (PL) results in increased rima glottidis size compared with PL alone.

Study Design: Experimental study.

Animals: Equine cadaver larynges (n=13).

Three-dimensional biomechanics of simulated laryngeal abduction in horses.

Objective: To investigate the influence of simulated contraction of the cricoarytenoideus dorsalis (CAD) muscle on the 3-D motion of the arytenoid cartilage.

Sample Population: 5 larynges from equine cadavers.

Procedures: Serial computed tomographic scans of each larynx were conducted at 7 incremental forces simulating contraction of medial, lateral, and combined bellies of the left CAD muscle.

Sinoscopic treatment of rostral maxillary and ventral conchal sinusitis in 60 horses.

Objective: To evaluate the use of sinoscopy for detection and treatment of ventral conchal sinus (VCS) and/or rostral maxillary sinus (RMS) disease in horses.

Study Design: Case series

Animals: Horses (n=60) with suspected paranasal sinus disease.

Methods: Horses were evaluated by sinoscopy through a conchofrontal sinus (CFS) portal with ventral conchal bulla (VCB) fenestration.

Comparison of sinoscopic techniques for examining the rostral maxillary and ventral conchal sinuses of horses.

Objective: To develop a reliable technique for sinoscopic examination of the ventral conchal (VCS) and rostral maxillary sinuses (RMS) of horses

Study Design: Descriptive study

Animals: Cadaveric equine heads (n=40)

Methods: The VCS and RMS were examined endoscopically using: (1) rostral trephination of the RMS (rostral RMS approach); (2) caudal trephination of the RMS (caudal RMS approach); (3) conchofrontal sinus (CFS) trephination followed by RMS trephination at a site identified by endoscopic transillumination of the maxillary bone at the most rostral aspect of the caudal maxillary sinus (CMS) (light-indicated RMS approach); (4) CFS trephination with fenestration of the ventral conchal bulla (VCB; frontal VCB approach); (5) CMS trephination with VCB fenestration (caudal VCB approach); and (6) CFS and CMS trephination with VCB fenestration (combined VCB approach).

Results: Success in observing the rostral and caudal aspects of the VCS and RMS with each approach were: (1) rostral RMS approach (0 horses; 16 horses [40%]); (2) caudal RMS approach (0 horses; 11 horses [28%]); (3) light-indicated RMS approach (3 horses [8%]; 24 horses [60%]); (4) frontal VCB approach (24 horses [60%]; 29 horses [73%] respectively); (5) caudal VCB approach (16 horses [40%] both structures); and (6) combined VCB approach (27 horses [68%]; 35 horses [88%]).

Conclusions: Trephination into the CFS coupled with fenestration of the VCB provided consistent access to both the rostral and caudal aspects of the RMS and VCS.