The larynx in horses is a complex anatomical structure located in the throat, playing a critical role in respiration, phonation, and airway protection. It consists of cartilages, muscles, and ligaments that work together to regulate airflow into the trachea and produce vocal sounds. The equine larynx is susceptible to various conditions, such as laryngeal hemiplegia, which can impact a horse's breathing and performance. This page aggregates peer-reviewed research studies and scholarly articles that explore the anatomy, function, disorders, and clinical management of the larynx in horses, providing insights into diagnostic techniques and therapeutic interventions.
Parente EJ, Birks EK, Habecker P.To perform a modification to the standard laryngoplasty procedure in vivo that would result in ankylosis of the cricoarytenoid (CA) joint, and determine the stability provided to the abducted arytenoid in vitro. Methods: Experimental study. Methods: Horses (n=8). Methods: Horses were assigned to either control laryngoplasty (n=3) or modified laryngoplasty (5) procedure. Endoscopic upper airway evaluations were used to measure right:left quotients 1 day and 3 months postoperatively to assess maintenance of abduction. Horses were euthanatized 3 months after surgery and larynges collected for mea...
Lacourt M, Marcoux M.To report use of a shielded hook bistoury developed for correction of epiglottic fold entrapment in standing sedated horses. Methods: Prospective clinical study. Methods: Standardbreds (n=8), 3-19 years of age. Methods: Epiglottic fold entrapment was corrected during standing sedation using a shielded hook bistoury passed nasally into the pharynx. Owners, trainers, and referring veterinarians were contacted by telephone to establish outcome. Results: Axial division of the entrapping epiglottic fold was successful in all horses. No short- or long-term complications occurred. Axial transection o...
Garrett KS, Woodie JB, Cook JL, Williams NM.A foal was examined for abnormal upper airway noise. Endoscopically, there were narrowed nasal passages and an extralumenal mass of the cranial trachea. Using ultrasonography and magnetic resonance (MR) imaging of the larynx and cranial cervical trachea, irregular margins of the laryngeal cartilages and first tracheal ring containing areas consistent with fluid were identified. In MR images, a widened nasal septum was seen that contained material consistent with fluid. Postmortem examination confirmed the diagnosis of nasal septal, laryngeal, and cranial cervical tracheal cyst-like lesions. Th...
Perkins JD, Raffetto J, Thompson C, Weller R, Piercy RJ, Pfau T.To investigate the influence of simulated contraction of the cricoarytenoideus dorsalis (CAD) muscle on the 3-D motion of the arytenoid cartilage. Methods: 5 larynges from equine cadavers. Methods: 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. Three-dimensional reconstruction of radiopaque markers placed at anatomic landmarks on the left arytenoid and cricoid cartilages enabled quantification of marker displacement according to a Cartesian coordinate system. Rotatio...
Vanschandevijl K, Nollet H, Vonck K, Raedt R, Boon P, Roost D, Martens A, Deprez P.The aim of this study was to assess the feasibility of implanting an existing vagus nerve stimulating (VNS) electrode around the recurrent laryngeal nerve. The stimulus response characteristics required to achieve abduction of the ipsilateral arytenoid by the VNS electrode in the normal horse could then be determined. The electrode was wound around the left recurrent laryngeal nerve at the cervical level and connected to a pulse generator. Stimulus response characteristics were obtained by measuring stimulated arytenoid displacement endoscopically in the standing, non-sedated horse. A full and...
Fey K.Horses are obligate nasal breathers and depend on patency of their nasal passages. Several dynamic obstructive diseases in the pharyngeal and laryngeal area can be differentiated by high speed treadmill endoscopy and may be responsible for impaired exercise tolerance in the equine athlete. The anatomical specialty of guttural pouches predisposes the horse to species-specific diseases.
Allen KJ, Franklin SH.To date there is no information on the comparison of the more recently documented technique of performing endoscopy during ridden exercise in the field, with the more traditional method of endoscopy during high-speed treadmill exercise. Objective: To compare the results of upper respiratory tract endoscopy in UK Thoroughbred racehorses performed during ridden exercise in the field with those obtained during exercise on the treadmill. Methods: A direct comparison was undertaken in 4 horses whereby both procedures were performed in the same horse within 10 days of each other. An indirect compari...
Diab S, Pascoe J, Shahriar M, Read D, Kinde H, Moore J, Odani J, Uzal F.There is increasing anecdotal evidence among horse owners, trainers and equine clinicians of a high prevalence of subepiglottic ulcers, suggested to have a negative effect on racing performance. Objective: To provide a prevalence study and pathological characterisation of laryngopharyngeal lesions with emphasis in the subepiglottic area and, in particular, subepiglottic ulcers. Methods: The study was carried out on 91 Thoroughbred racehorses received for post mortem examination from 4 major Southern California racetracks. The most common reason for submission was catastrophic musculoskeletal i...
Nolen-Walston RD, Parente EJ, Madigan JE, David F, Knafo SE, Engiles JB.This clinical report describes 8 cases of branchial remnant cysts (BRC) in the horse. The horses presented with bimodal age distribution, with 5 cases in mature horses (age 8-21 years) and 3 in foals (age 1, 6 and 10 months). Mature cases presented for dysphagia or intermittent oesophageal obstruction (2/5), and retropharyngeal swelling (3/5), whereas respiratory stridor and visible mass were presenting complaints in the foals. Presence of a right-sided (5/8) or dorsally located (2/8) palpable retropharyngeal mass of 3-35 cm diameter was noted clinically; one left-sided mass was identified as ...
Garrett KS, Pierce SW, Embertson RM, Stromberg AJ.OBJECTIVE-To determine the association between results of endoscopic evaluation of arytenoid function (AF) and epiglottic structure (ES) in Thoroughbred yearlings and racing performance at 2 to 4 years of age. DESIGN-Retrospective case series. ANIMALS-2,954 Thoroughbred yearlings. Procedures-Records of yearlings that had endoscopic evaluation of the larynx between 1998 and 2001 were obtained, and results were graded by use of standardized scales. A modified Havemeyer scale (grade I, II.1, II.2, III, or IV) was used to evaluate AF; ES was graded on a scale of 0 to IV. Records were annotated if ...
Tatarniuk DM, Carmalt JL, Allen AL.To report intraoperative complications during needle penetration and suture placement through the cricoid cartilage during a prosthetic laryngoplasty procedure. Methods: Case report. Methods: An 11-year-old American Paint gelding with grade IV left laryngeal hemiplegia underwent a terminal prosthetic laryngoplasty for teaching purposes. Passage of the needle through the cricoid cartilage was difficult and resulted in needle breakage before eventual success using a new needle. The larynx was examined postmortem. Results: Palpation of the larynx revealed hardening of the cricoid cartilage. Radio...
Ortved KF, Cheetham J, Mitchell LM, Ducharme NG.Caudal descent of the larynx has been proposed to be associated with intermittent dorsal displacement of the soft palate (DDSP) as it leads to a loss of the seal between the epiglottis and soft palate but further investigation of this theory is required. Objective: To evaluate laryngohyoid position of horses with persistent DDSP in comparison to horses with intermittent DDSP and evaluate the outcome of treatment. Objective: Horses with persistent DDSP have a different laryngohyoid position compared to those with intermittent DDSP. Horses with persistent DDSP can be returned successfully to rac...
Matsuda K, Qiu Y, Furuse T, Kawamura Y, Yokoyama D, Kato A, Taniyama H.This report documents an unusual case of congenital foregut cyst with dysphagia and stridor in a Thoroughbred foal. Histologically, the bilocular cyst, near the junction of larynx and trachea, had an epithelial lining of bronchogenic and esophageal origin. Concomitant malformation of the laryngeal muscles and cartilage resulted in a combination of anomalies that have not been reported in the human or veterinary literature.
Saulez MN, Gummow B.Endoscopic examinations were performed on 1005 thoroughbred racehorses in South Africa a mean (sd) 24 (12.3) minutes after racing, to determine the prevalence of pharyngeal, laryngeal and tracheal disorders, and to determine the relationship of these disorders with performance (number of wins and placed finishes). Overall, there was a low prevalence of grade 2 and 3 laryngeal function (LF) (2.2 per cent), grade 4 LF (0.6 per cent), epiglottic entrapment (1.3 per cent), subepiglottic cyst (0.2 per cent) and epiglottic deformity (0.6 per cent), while a higher prevalence of grade 2 to 4 pharyngea...
Carstens A, Kirberger RM, Grimbeek RJ, Donnellan CM, Saulez MN.Radiographic measurement of tracheal dimensions in the horse may be useful in evaluating upper and lower respiratory tract conditions due to the gradient of pressure changes between these areas. Lateral radiographs of the trachea of 15 normal sedated Thoroughbred horses were made at inspiration and expiration and magnification-corrected mean airway heights measured were, respectively: larynx: 5.89 and 5.86 cm; trachea at the third cervical vertebra (C3): 4.17 and 4.04cm; at the fifth cervical vertebra (C5): 3.62 and 3.59 cm; at the first thoracic vertebra (T1): 3.4 and 3.23cm; and carina: 3.85...
Pekarkova M, Kircher PR, Konar M, Lang J, Tessier C.The purpose of the present study was to describe normal magnetic resonance (MR) imaging anatomy of the equine larynx and pharynx and to present the optimal protocol, sequences, and possible limitations of this examination technique. Using a 0.3 T unit, the laryngeal and pharyngeal regions was imaged in two horses. The protocol consisted of sagittal and transverse T2-weighted (T2w) fast spin echo, transverse T1-weighted (T1w) spin echo, and dorsal high-resolution T1w gradient echo (both pre- and postcontrast enhancement) sequences. Euthanasia was performed at the end of the imaging procedure. M...
Pollock PJ, Reardon RJ, Parkin TD, Johnston MS, Tate J, Love S.There are potential advantages to imaging the upper portion of the respiratory tract (URT) of horses during ridden exercise. With the advent of a wireless endoscope, this is now possible. However, there has been no detailed validation of the technique and findings have not been compared to ridden speed. Objective: To assess the combined use of a Dynamic Respiratory Scope (DRS) and global positioning system (GPS) receiver for examining the URT of a group of Thoroughbred racehorses randomly selected from a single flat racehorse training establishment. Methods: Horses were selected randomly from ...
Cramp P, Derksen FJ, Stick JA, de Feijter-Rupp H, Elvin NG, Hauptman J, Robinson NE.The nerve-muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Objective: The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods: Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead-weight force generator applied a force of 0-14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70 degrees angles. The r...
Dart A, Tee E, Brennan M, Dart C, Perkins N, Chapman S, Debney S.To assess the effect of 1 or 2 laryngeal prosthetic sutures on rima glottidis areas in equine laryngeal specimens. Methods: Experimental, randomized design. Methods: Cadaveric equine larynges (n=16). Methods: Larynges were collected from 10 horses; 2 sutures each were preplaced in the right and left sides of each larynx. A dorsal suture (DS) was placed through the caudal rim of the dorsal midline of the cricoid cartilage, under the cricopharyngeus muscle and through the proximal and rostral aspect of the muscular process. A lateral suture (LS) was placed 1.5 cm lateral to the DS and through th...
Collins N, Milne E, Hahn C, Dixon P.The establishment of a single validated endoscopic laryngeal grading system for assessing recurrent laryngeal neuropathy (RLN) is desirable to facilitate direct comparisons between the findings of different clinical and research groups worldwide. The objective of this study was to assess the relationship between the Havemeyer endoscopic laryngeal grading system and histopathological changes consistent with RLN in the left cricoarytenoideus dorsalis (CAD) muscle of horses of different breeds with a full range of clinical severities of RLN, i.e., from normal endoscopic laryngeal function to comp...
Rhee HS, Steel CM, Derksen FJ, Robinson NE, Hoh JF.We used immunohistochemistry to examine myosin heavy-chain (MyHC)-based fiber-type profiles of the right and left cricoarytenoideus dorsalis (CAD) and arytenoideus transversus (TrA) muscles of six horses without laryngoscopic evidence of recurrent laryngeal neuropathy (RLN). Results showed that CAD and TrA muscles have the same slow, 2a, and 2x fibers as equine limb muscles, but not the faster contracting fibers expressing extraocular and 2B MyHCs found in laryngeal muscles of small mammals. Muscles from three horses showed fiber-type grouping bilaterally in the TrA muscles, but only in the le...
Chalmers HJ, Yeager AE, Ducharme N.Dorsal displacement of the soft palate is an important cause of poor performance in racehorses, yet its etiology is not fully understood. Diagnosis requires treadmill videoendoscopy, which is not widely available. The relationship of the larynx, the hyoid apparatus, and the remainder of the skull may be important in predisposing horses to dorsal displacement of the soft palate. We hypothesized that this relationship could be accurately assessed in unsedated horses through ultrasonographic examination. Fifty-six racehorses presented for evaluation of poor performance were subjected to treadmill...
Rakesh V, Ducharme NG, Cheetham J, Datta AK, Pease AP.The necessary degree of arytenoid cartilage abduction (ACA) to restore airway patency at maximal exercise has not been determined. Objective: Use computational fluid dynamics modelling to measure the effects of different degrees of ACA on upper airway characteristics of horses during exercise. Objective: Maximal ACA by laryngoplasty is necessary to restore normal peak airflow and pressure in Thoroughbred racehorses with laryngeal hemiplegia. Methods: The upper airway was modeled with the left arytenoid in 3 different positions: maximal abduction; 88% cross-sectional area of the rima glottis; a...
Kelly JR, Carmalt J, Hendrick S, Wilson DG, Shoemaker R.To compare biomechanical properties of 6 suture configurations using a large diameter polyester prosthesis in the muscular process (MP) of the arytenoid cartilage and to determine failure mode. Methods: Experimental study. Methods: Cadaveric equine larynges (n=121). Methods: Suture configurations (4 single, 2 double) were inserted, and then constructs were tested in a single-cycle to failure at a 100 mm/min distraction. Load deformation curves were generated to assess the biomechanical properties of each construct. A 1-way ANOVA was used to compare the mean differences in construct failure for...
McCluskie LK, Franklin SH, Lane JG, Tremaine WH, Allen KJ.To assess the effect of head position on relative position of the larynx and hyoid apparatus in horses with palatal dysfunction, and to define a standard position for radiographic assessment of laryngeal tie-forward. Methods: Prospective clinical study. Methods: Adult horses (n=9) with palatal dysfunction. Methods: Left lateral radiographs of the larynx were obtained pre and postoperatively for 3 different head positions (flexed=90 degrees ; neutral=100 degrees ; extended=115 degrees ). Distance between thyrohyoid bone and thyroid cartilage was measured. Data were analyzed to investigate diffe...
Dougherty SS, Palmer JL.A 4-year-old horse was evaluated for chronic coughing, mucopurulent nasal discharge, and failure to thrive. Results: Endoscopy was performed on the larynx, pharynx, and trachea and revealed an approximately 2-cm fluctuant subepiglottic cyst. Results: The subepiglottic cyst was treated with intralesional formalin administration. Following 2 injections, 2 weeks apart, the cyst was completely resolved with no evidence of scarring or epiglottic deformity. Conclusions: Findings suggest that intralesional formalin administration for treatment of subepiglottic cysts may be a minimally invasive, econo...
Cheetham J, Witte TH, Rawlinson JJ, Soderholm LV, Mohammed HO, Ducharme NG.The success of laryngoplasty is limited by abduction loss in the early post operative period. Objective: To determine the efficacy of polymethylmethacrylate (PMMA) in stabilising the cricoarytenoid joint (CAJ) and reducing the force on the laryngoplasty suture. Objective: Injection into the cricoarytenoid joint resists the forces produced by physiological laryngeal air flows and pressures thereby reducing the force experienced by the laryngoplasty suture. Methods: Ten cadaver larynges were collected at necropsy and PMMA was injected into one CAJ at selected random. Each larynx was subjected to...
Fulton IC, Stick JA, Derksen FJ.Left laryngeal hemiplegia is a frustrating condition for the equine athlete and equine veterinarian. Treatment for the past 30 years has centered on the prosthetic laryngoplasty ("tie-back") with or without ventriculectomy. Laryngeal reinnervation has been used successfully in people and has been shown experimentally to benefit affected horses. This article reviews equine laryngeal reinnervation using the nerve muscle pedicle graft and describes the surgical technique, its complications, and the follow-up in 146 cases treated over the past 10 years. Also discussed is ongoing research into stim...
Santos MP, Gutierrez-Nibeyro SD, Horn GP, Johnson AJ, Stewart MC, Schaeffer DJ.To compare the mechanical properties of laryngeal tie-forward (LTF) surrogate constructs prepared with steel fixtures and No. 5 braided polyester or braided polyethylene by use of a standard or a modified suture placement technique. Methods: 32 LTF surrogate constructs. Methods: Surrogate constructs were prepared with steel fixtures and sutures (polyester or polyethylene) by use of a standard or modified suture placement technique. Constructs underwent single-load-to-failure testing. Maximal load at failure, elongation at failure, stiffness, and suture breakage sites were compared among constr...
McClellan NR, Santschi EM, Hurcombe SD, Litsky AS.To (1) develop a model of cyclical adduction force on an abducted left arytenoid cartilage that mimics swallowing or coughing; (2) determine if arytenoid abduction by a clamp before knot tying will improve the maintenance of abduction under cyclical adduction testing. Methods: Experimental. Methods: Cadaveric equine larynges (n = 14). Methods: Left laryngoplasty performed using a single suture of #5 Ethibond with (n = 7) and without (n = 7) abducting the arytenoid with a clamp before knot tying. Each laryngoplasty was loaded cyclically from 2 to 26 N at 0.5 Hz for 5000 cycles i...
Pardo Mateu L, Faubel Serra M, Llavero Segovia MT, Cano Cuenca B, Pérez Climent F, Giménez Vaillo F, Grau Alario E, Lazaro Santander R.The Rhodococcus equi is an aerobic gram positive pleomorphic bacillus, that was isolated for the first time like a producer of bronchopneumonia in young horses. Every time more often, it is being recognized as a pathogen in humans, mainly in the immunodepressed population. We described a case, until now exceptional, of laryngeal infection by Rhodococcus equi in a patient with positive serology for the virus of the human immunodeficiency (HIV), and we reviewed some clinical and epidemiological characteristics of the infections by this germ. The treatment is riphampicine and/or erythromycin, bei...
Perkins JD, Hughes TK, Brain B.To describe and evaluate the use of a transoral, endoscope-guided technique for transection of an entrapping epiglottic fold in sedated standing horses. Methods: Retrospective study. Methods: Horses (n=16) with epiglottic fold entrapment (EFE). Methods: Medical records (2005-2006) of 16 horses with EFE were reviewed to determine history, physical and endoscopic examination findings, postoperative complications, and outcome after axial division of EFE using a hooked bistoury, under an endoscopic-guided, transoral approach. Results: EFE was confirmed by endoscopy. Axial division was successfully...
Quinlan TJ, Goulden BE, Barnes GR, Anderson LJ, Cahill JI.The nerve supply to the intrinsic laryngeal muscles of the horse was studied by gross dissection and by electromyography which was carried out before, during and after section of various intralaryngeal nerve branches. The anatomical relationships and passage of the laryngeal nerves throughout the larynx were defined. Unlike the dog and man there was no evidence of the passage of motor nerve fibres from one side of the larynx to the other.
Jones DL.Medical records were reviewed for 11 horses with squamous cell carcinoma of the larynx and/or pharynx. The average age at presentation was 15.3 years. No breed or sex predilection was present. At presentation, 6 of 11 horses were dyspneic and 4 horses had inspiratory stridor. Endoscopy was performed in all cases and was more useful in demonstrating a mass in the laryngopharyngeal region than laryngeal or guttural pouch radiography. Surgical excision was attempted in 3 horses and in 1 horse alleviated clinical signs for 4 months. Ten horses were euthanatized and 1 horse died. Results of this st...
Kirkham LE, Vasey JR.An Anglo-Arab foal with bilateral postprandial nasal discharge was diagnosed as having a full-length defect of the soft palate. Surgical repair was attempted using a combination of two surgical approaches. Initially a mandibular symphysiotomy approach was used. The posterior portion of the defect did not heal adequately, so a ventral laryngotomy, bisecting the body of the thyroid cartilage and extending to a pharyngotomy approach, was performed 5 months later. The foal has since matured fully despite a slight unilateral nasal discharge. This case report demonstrates that these two surgical app...
Scarratt WK, Crisman MV.Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.
Lopez-Plana C, Sautet JY, Ruberte J.Three adductor muscles of the larynx, the cricoarytenoideus lateralis (CAL), the arytenoideus transversus (AT) and the ventricularis (Ve), from 36 horses were examined histologically. The neurogenic changes seen in each muscle were evaluated qualitatively. In addition, in 6 horses with clinical and subclinical signs of neurogenic atrophy, measurements of muscle fibre area were performed. Neurogenic changes observed in the Ve were less than in CAL and AT. Measurements of muscle fibre area also demonstrated that CAL and AT showed a wider range of pathological changes than did Ve. The results sho...
Tomasic M, Mann LS, Soma LR.To determine the effects of endotracheal intubation on respiratory mechanics during xylazine sedation and xylazine-diazepam-ketamine anesthesia in adult horses. Methods: 5 healthy adult horses. Methods: Measurements were derived from recordings of respiratory gas flow, and transpulmonary and transtracheal pressures. Total pulmonary resistance (RT) was partitioned into upper airway resistance (extrathoracic portion of trachea, larynx, pharynx, nasal cavity, nares; RUA) and lower airway resistance (intrathoracic portion of trachea, bronchi, bronchioles). Baseline measurements were obtained in un...
Tucker ML, Sumner D, Reinink SK, Wilson DG, Carmalt JL.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. Methods: 28 cadaveric equine larynges. Methods: Each larynx in states of simulated left RLN alone and with airway interventio...
Gray SM, Gutierrez-Nibeyro SD, Couëtil LL, Horn GP, Kesler RM, McCoy AM, Stewart MC, Schaeffer DJ.To evaluate the airway mechanics of modified toggle LP constructs in an airflow chamber model and compare these to the airway mechanics of standard LP constructs. Methods: Ex-vivo experimental study. Methods: Fifty-one equine cadaveric larynges. Methods: Bilateral LP constructs were performed using a modified toggle (n = 23) or a standard (n = 21) LP technique. Constructs were tested in an airflow model before and after cyclic loading which was designed to mimic postoperative swallowing. The cross-sectional area (CSA), peak translaryngeal airflow (L/s), and impedance (cmH 0/L/s) were deter...
Dougherty SS, Palmer JL.A 4-year-old horse was evaluated for chronic coughing, mucopurulent nasal discharge, and failure to thrive. Results: Endoscopy was performed on the larynx, pharynx, and trachea and revealed an approximately 2-cm fluctuant subepiglottic cyst. Results: The subepiglottic cyst was treated with intralesional formalin administration. Following 2 injections, 2 weeks apart, the cyst was completely resolved with no evidence of scarring or epiglottic deformity. Conclusions: Findings suggest that intralesional formalin administration for treatment of subepiglottic cysts may be a minimally invasive, econo...
Hance SR, Bertone AL.Equine tumors are rather uncommon; however, of the body regions, the head is a relatively common location for neoplasia, including sarcoids and squamous cell carcinomas of the skin, tumors of the sinus/nasal cavity, and bony tumors of the head. Tumors discussed in the article include odontogenic and bony tumors; sarcoids; tumors of the guttural pouch and pharyngeal and oral mucosa; tumors of the larynx; and tumors of the paranasal sinuses and nasal passages. In general, tumors involving deeper structures of the head carry a poor prognosis; however, some tumors such as sarcoids, ossifying fibro...
Mirazo JE, Page P, Rubio-Martinez L, Marais HJ, Lyle C.Upper airway endoscopy at rest has been the diagnostic method of choice for equine upper respiratory tract (URT) conditions. Development of high-speed treadmill endoscopy improved the sensitivity of URT endoscopy by allowing observation of the horse's nasopharynx and larynx during exercise. However, treadmill exercise may not always accurately represent the horse's normal exercise as track surface, rider, tack and environmental variables are altered. Recently, the development of dynamic overground endoscopy (DOE) has addressed some of these shortcomings. A retrospective study was undertaken to...
Diab S, Pascoe J, Shahriar M, Read D, Kinde H, Moore J, Odani J, Uzal F.There is increasing anecdotal evidence among horse owners, trainers and equine clinicians of a high prevalence of subepiglottic ulcers, suggested to have a negative effect on racing performance. Objective: To provide a prevalence study and pathological characterisation of laryngopharyngeal lesions with emphasis in the subepiglottic area and, in particular, subepiglottic ulcers. Methods: The study was carried out on 91 Thoroughbred racehorses received for post mortem examination from 4 major Southern California racetracks. The most common reason for submission was catastrophic musculoskeletal i...
Kallmyr A, Giving EM, Moen LO, Øverlie M, Holm T, David F.To describe a resection technique of the alar folds in the standing horse. Methods: Retrospective case study. Methods: Eight Standardbred racing trotters. Methods: Horses in which alar fold collapse had been diagnosed between 2017 and 2018 were included in this study. All horses underwent alar fold resection under standing sedation and regional anesthesia with a bipolar electrosurgical open sealer/divider device (LigaSure). Intraoperative and postoperative complications were recorded. A Wilcoxon signed-rank test was used to compare differences in median prize money earning pre-surgery and post...
Kelly JR, Carmalt J, Hendrick S, Wilson DG, Shoemaker R.To compare biomechanical properties of 6 suture configurations using a large diameter polyester prosthesis in the muscular process (MP) of the arytenoid cartilage and to determine failure mode. Methods: Experimental study. Methods: Cadaveric equine larynges (n=121). Methods: Suture configurations (4 single, 2 double) were inserted, and then constructs were tested in a single-cycle to failure at a 100 mm/min distraction. Load deformation curves were generated to assess the biomechanical properties of each construct. A 1-way ANOVA was used to compare the mean differences in construct failure for...
Barton AK, Troppenz A, Klaus D, Lindenberg I, Merle R, Gehlen H.There is contradictory evidence on the potential benefits of tongue ties on upper airway function and their efficacy in inhibiting intermittent dorsal displacement of the soft palate (DDSP) in racehorses. Objective: To test the hypothesis that tongue ties increase the pharyngeal diameter and decrease the occurrence of dynamic airway obstruction in racehorses. Methods: Prospective, crossover blinded clinical study. Methods: Data of 22 Thoroughbred and 8 Standardbred racehorses examined using overground endoscopy under full-intensity exercise on training racetracks with and without fixation of t...
Dean PW.Abnormalities of the nasal cavity, pharynx, larynx, and trachea result in respiratory noise and exercise intolerance. Clinical features of common upper respiratory conditions of performance horses are reviewed with emphasis on diagnosis, treatment, and risk factors that affect the outcome of surgical treatment.
Brandenberger O, Martens A, Robert C, Wiemer P, Pamela H, Vlaminck L, Barankova K, Haspeslagh M, Perkins JD, Ducharme N, Rossignol F.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. Methods: Ex vivo cadaveric study. Methods: Five isolated equine larynges and 39 equine head and neck specimens. Methods: The anatomy of the vestibulum esophagi was studied by dissection of 5 cadaver specimens. Then, a bilateral laryngoplasty was performed, including 5 suture placements through the muscular processes, caudal, rostral, and sagittal, with straight and curved needles. Two of the 3 surgeons performing the implanta...
Curtiss AL, Aceto H, Embertson RM.Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. Objective: To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post-operatively. Methods: Retrospective cohort and case-control studies. Methods: Medical (1989-2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre- and post-operative endoscopic images and surgic...
Nolen-Walston RD, Parente EJ, Madigan JE, David F, Knafo SE, Engiles JB.This clinical report describes 8 cases of branchial remnant cysts (BRC) in the horse. The horses presented with bimodal age distribution, with 5 cases in mature horses (age 8-21 years) and 3 in foals (age 1, 6 and 10 months). Mature cases presented for dysphagia or intermittent oesophageal obstruction (2/5), and retropharyngeal swelling (3/5), whereas respiratory stridor and visible mass were presenting complaints in the foals. Presence of a right-sided (5/8) or dorsally located (2/8) palpable retropharyngeal mass of 3-35 cm diameter was noted clinically; one left-sided mass was identified as ...
Virgin JE, Holcombe SJ, Caron JP, Cheetham J, Kurtz KA, Roessner HA, Ducharme NG, Hauptman JG, Nelson NC.Pharyngeal dysphagia is a debilitating, sometimes fatal condition in horses, with multiple aetiologies. The pathophysiology is complex and not fully understood. Treatment is largely supportive. Laryngeal advancement surgery may diminish symptoms of dysphagia and improve swallowing in affected horses. Objective: 1) to induce reversible moderate and marked pharyngeal dysphagia by regional anaesthesia of branches of the glossopharyngeal (IX), vagus (X) and hypoglossal (XII) nerves; 2) to characterise the dysphagia produced by each model; and 3) to determine whether laryngeal advancement surgery i...
Tulleners E, Mann P, Raker CW.Epiglottic augmentation with injectable bovine collagen or an autogenous or allogenous auricular cartilage graft was performed in 12 horses with endoscopically and radiographically normal epiglottises. The grafting procedures were easy to perform and did not cause apparent discomfort. Cartilage graft extrusion or resorption may have occurred, but was not seen by endoscopy and lateral laryngeal radiography. Only collagen implants remained evident endoscopically, as smooth round submucosal bulges ventral to the epiglottic cartilage. Two horses with collagen implants, and all horses with cartilag...
Barnes AJ, Slone DE, Lynch TM.To examine the effect of partial arytenoidectomy without mucosal closure on postoperative racing performance and long-term complications in Thoroughbred racehorses treated for laryngeal hemiplegia, arytenoid chondropathy, or failed laryngoplasty. Methods: Retrospective study. Methods: Twenty-seven Thoroughbred racehorses. Methods: Medical records of Thoroughbred racehorses that had partial arytenoidectomy without mucosal closure between 1992 and 2002 were reviewed. Horses were divided into groups: horses that had not raced (Group 1) and those that had raced (Group 2) before surgery. Lifetime r...
