Endoscopy in horses refers to a diagnostic procedure that involves the use of an endoscope, a flexible tube equipped with a camera and light, to visually examine the interior surfaces of equine organs and tissues. This technique is commonly employed to investigate conditions affecting the respiratory tract, gastrointestinal tract, and other internal structures. Endoscopy allows for direct visualization and assessment of abnormalities such as lesions, obstructions, or inflammation. It can also be used to obtain biopsies or remove foreign bodies. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, methodologies, and clinical relevance of endoscopy in equine medicine.
Deegen E, Müller P, Petzoldt K.On the basis of cytological similarities in chronic obstructive disease (COPD) in human beings and in horses during 1981 a total number of 144 horses with COPD were examined. Bronchial secretions were taken under endoscopic control and stained with a modified Hansel staining procedure. Whereas 26 horses did not exhibit signs of allergic reactions cytologically and 94 horses showed low amounts of eosinocytes and/or mast cells in their secretion; only the secretions of 24 horses (16,67%) were characterized by fairly high contents of these allergy associated cells and low numbers of neutrophilic ...
Barber SM.A three year old Thoroughbred filly was examined because of bilateral nasal discharge and external swelling of the left laryngeal area. Endoscopy revealed an enlarged left arytenoid cartilage, left laryngeal hemiplegia and drainage of purulent material into the lumen of the larynx. Radiographs showed a large fluid and gas filled cavity overlying the caudal larynx and cranial trachea. Surgical drainage and debridement of the abscess led to complete healing by secondary intention. Laryngeal ventriculectomy was performed as a treatment for left laryngeal hemiplegia, but a grave prognosis for resp...
Greet TR.Three horses were referred for investigation of a unilateral foul smelling scanty nasal discharge, complicated in one case by intermittent epistaxis. Thick purulent material or a mycotic plaque was identified by an endoscopic examination of the middle meatus but in two horses this had to be repeated under general anaesthesia before the abnormalities were detected. Aspergillus fumigatus was cultured from all three cases and septate hyphae were identified on smears from lesions. Histological examination of the lesion in one case revealed a fungal mycelium. Topical treatment with natamycin soluti...
Goulden BE, Anderson LJ.Some clinical features of laryngeal hemiplegia in 127 horses are described. Possible aetiologic factors were found in only 11% of affected animals. The onset of clinical signs was either sudden or insidious. The majority of cases were presented because of an abnormal respiratory noise made at exercise. Other clinical signs, particularly those usually attributed to laryngopalatal dislocation, were observed in a substantial proportion of affected animals. In all cases surveyed the left arytenoid was affected, although in 3 animals a bilateral laryngeal dysfunction was noted. Thirty of 65 animals...
Haynes PF.Persistent dorsal displacement of the soft palate was diagnosed in 2 Thoroughbred horses examined because of decreased exercise tolerance and a respiratory noise during strenuous exercise. The persistent dorsal displacement of the soft palate was caused by an epiglottis that was approximately 2/3 normal size, and thus was incapable of maintaining the soft palate in a normal subepiglottic position. Contrast pharyngography suggested a primary epiglottic abnormality. Visual assessment of the lesion was accomplished by exploratory ventral laryngotomy and endoscopy of the oropharynx per os. Surgica...
Stick JA, Krehbiel JD, Kunze DJ, Wortman JA.Esophageal healing was evaluated in 10 ponies after sutured and nonsutured cervical esophagotomy techniques. Mucosal healing occurred significantly (P less than 0.005) faster after sutured esophagotomies (x = 7.5 days after surgery) than after nonsutured esophagotomies (x = 25.6 days after surgery), based on endoscopic and clinical evaluations. Although endoscopy was an accurate assessment of the return of normal passage of a food bolus through the esophagus, 4 of 10 ponies had radiographic evidence of a sinus tract after the mucosa was considered healed, based on endoscopic and clinical exami...
Haynes PF, Snider TG, McClure JR, McClure JJ.Chronic chondritis of the arytenoid cartilage was diagnosed in 7 male Thoroughbred horses examined for obstructive upper airway disorders. The history of the cases was characterized by a 3- to 6-month progression of exercise intolerance and inspiratory dyspnea during exercise. Endoscopy revealed marked asymmetry of the rima glottidis, partial or complete inability to abduct the involved cartilage, and axial displacement of the involved arytenoid cartilage. In less severe cases, the disorder was confused with laryngeal hemiplegia. Focal elevated lesions of the involved cartilage, which were fre...
Nickels FA, Brown CM, Breeze RG.A unilateral pulmonary granular cell tumor occurred in a Thoroughbred mare with longstanding respiratory disease wrongly attributed to chronic obstructive pulmonary disease. The clinical features, radiology and endoscopic appearance permitted an accurate diagnosis, which was supported by subsequent necropsy and histologic examination. Obstructive pulmonary disease was ruled out after measurement of arterial blood gases and maximum intrathoracic pressure changes, and after microscopic examination of the lung.
Heffron CJ, Baker GJ, Lee R.Videofluoroscopy was used to study the deglutition reflexin 2 horses believed, on the basis of endoscopic and clinical examination, to have normal pharyngeal and laryngeal function. The reflex was found to be the same as that described in man and in the rabbit. A feature of deglutition in the horse was the temporary increase in size of the auditory tube diverticuli (gluttural pouches) as a result of contraction of the pharyngeal muscles.
Heffron CJ, Baker GJ.Cine-endoscopy was used to study the deglutition reflex in 2 apparently normal horses. Closure of the nasopharyngeal sphincter was brought about by a lowering of the pharyngeal roof and an elevation of the soft palate caudal to the pharyngeal ostia of the auditory tubes. The medial cartilages of the ostia were not directly involved in bringing about closure of the sphincter. It is postulated that the opening of the ostia of the auditory tubes is brought about during deglutition by the combined action of the palatopharyngeus, pterygopharyngeus and tensor veli palatini muscles.
Heffron CJ, Baker GJ.Fibreoptic endoscopy was used to study the movements of the larynx and pharynx during nasal occlusion in 10 horses, which showed signs consistent with functional pharyngeal obstruction (FPO) on exercise. Cine-endoscopic films were made on 3 such horses. Consideration of the anatomy of the region indicates that FPO may best be regarded as a subluxation of the nasopharyngeal and larygneal airways and it was found that a constant component of the movements which brought about this subluxation was a marked caudal retraction of the larynx. It is suggested that this caudal retraction of the larynx o...
Mather EC, Refsal KR, Gustafsson BK, Seguin BE, Whitmore HL.Intrauterine fibroscopy was used in the clinical evaluation of 40 mares with established histories of subfertility. The average age of the mares was 12.2 years with a 2.8-year interval from last foaling in multiparous mares. Transluminal adhesions, endometrial cysts, diffuse fibrosis, fluid accumulation or myometrial tumours were found in 26 mares. When compared to other techniques, fibroscopy did not seem to be superior to uterine biopsy but had some advantage over rectal palpation as a single diagnostic technique. Only 3 mares failed to exhibit pathological findings when all 3 techniques wer...
Heinze H.A method of endoscopic examination of the internal genital (pelvic) organs of the mare is described. Special emphasis is placed on the induction of artificial pneumoperitoneum and the installation of an endoscopic peritoneal fistula device for prolonged observation. The potential of pelviscopy in the mare as a diagnostic aid, a new device for research in equine reproduction and as an auxillary aid to teaching is discussed.
The upper respiratory tract is a frequent cause of exercise intolerance in horses, particularly in racing horses. There are a myriad of laryngeal abnormalities that may restrict airflow at the rima glottidis. Careful endoscopic examination is a crucial part of the examination of any racing horse suffering from poor performance. There has recently been interest in spectrum analysis of respiratory sounds. It has been determined that laryngeal hemiplegia and dorsal displacement of the soft palate have unique sound patterns. Therefore, spectrum analysis of respiratory sounds may prove to be useful...
Lane JG, Bladon B, Little DR, Naylor JR, Franklin SH.To review the prevalence of single and complex forms of dynamic airway obstructions within a large group of Thoroughbred horses in training referred for investigation of poor performance. Methods: Video-endoscopic recordings of the upper respiratory tract made during a standardised treadmill exercise test of 600 Thoroughbred racehorses were reviewed and analysed in real time and slow motion to identify dynamic collapse by the tissues bordering onto the pharyngeal and laryngeal airways. Results: Dynamic collapse within the nasopharynx or larynx was confirmed in 471 of the 600 horses. Dorsal dis...
Tetens J, Hubert JD, Eddy AL, Moore RM.A 2-year-old Thoroughbred filly was admitted to the hospital for evaluation of exercise intolerance. Resting videoendoscopic evaluation (i.e., while the horse was standing) of the nasopharynx and trachea revealed right arytenoid paresis and a tracheal defect that was 100 cm distal to the external nares. Surgery, consisting of a right prosthetic laryngoplasty, was performed. However, postoperative videoendoscopic evaluation revealed minimal abduction of the affected arytenoid cartilage. Dynamic videoendoscopic evaluation (i.e., while the horse was exercising) revealed the right arytenoid to be ...
Hawkins JF, Couetil L, Miller MA.The objective was to evaluate CO2 laser debridement of the cricoarytenoid joint (CAJ) combined with prosthetic laryngoplasty to prevent post-operative loss of arytenoid abduction in seven horses. Horses were assigned to either laser debridement of the left CAJ and laryngoplasty (laser treated, n=5) or control laryngoplasty (sham, n=2), and were evaluated with endoscopic examinations and measurement of right to left angle quotients (RLQ) to assess maintenance of arytenoid abduction. The animals were euthanased at intervals after surgery and larynges were harvested for post-mortem testing, inclu...
Nadruz V, Beard LA, Delph-Miller KM, Larson RL, Bai J, Chengappa MM.Prevention of spread of Streptococcus equi subspecies equi (S. equi) after an outbreak is best accomplished by endoscopic lavage of the guttural pouch, with samples tested by culture and real time, quantitative polymerase chain reaction (qPCR). Disinfection of endoscopes must eliminate bacteria and DNA to avoid false diagnosis of carrier horses of S. equi. Objective: Compare failure rates of disinfection of endoscopes contaminated with S. equi using 2 disinfectants (accelerated hydrogen peroxide [AHP] or ortho-phthalaldehyde [OPA]). The null hypothesis was that there would be no difference bet...
Newton-Clarke MJ, Divers TJ, Delahunta A, Mohammed HO.A study was conducted over a 12 month period to assess the specificity and sensitivity of the 'slap test', using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the 'slap test' and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exh...
Barakzai SZ, Wells J, Parkin TDH, Cramp P.Unilateral ventriculocordectomy (VeC) is frequently performed, yet objective studies in horses with naturally occurring recurrent laryngeal neuropathy (RLN) are few. Objective: To evaluate respiratory noise and exercising overground endoscopy in horses with grade B and C laryngeal function, before and after unilateral laser VeC. Methods: Prospective study in clinically affected client-owned horses. Methods: Exercising endoscopy was performed and concurrent respiratory noise was recorded. A left-sided laser VeC was performed under standing sedation. Owners were asked to present the horse for re...
Hellings IR, Larsen S.Gastric ulceration is highly prevalent in horses, and there is a large commercial market for feed-additives and non-licenced products that claim effect for prevention and treatment of gastric ulceration. ImproWin® has been used as a feed additive in horses with anecdotal evidence that it may have some positive effects on gastric ulceration.The aim of this study was to investigate the effect of ImproWin® treatment on spontaneously occurring gastric ulcers of the squamous mucosa in Standardbred and Coldblooded trotting racehorses. The study was performed as a randomised, double-blinded, single...
de Parades V, Bouchard D, Janier M, Berger A.Pilonidal disease is a frequent suppurative condition that occurs twice as often in men as in women, usually between the ages of 15 and 30. Pilonidal disease is located beneath the skin of the sacro-coccygeal region. It presents acutely as an abscess under tension while the chronic form gives rise to intermittent discharge from pilonidal sinus(es). Diagnosis is clinical and usually straightforward. In the large majority of cases, treatment is surgical but there is no consensus as to the 'ideal' technique. Acute abscess must be evacuated and an off-midline incision seems preferable. Excision is...
Eichentopf A, Snyder A, Recknagel S, Uhlig A, Waltl V, Schusser GF.A 20-year-old pony mare was presented to the equine hospital with a ten-day history of dysphagia, regurgitation and coughing. An obstruction of the oesophagus was excluded via endoscopy, but the proximal oesophagus appeared to be distended and circular contractions were missing. A guttural pouch endoscopy revealed a single, black-mottled plaque on the pharyngeal ramus of the vagus nerve in the left guttural pouch, causing a local swelling of this nerve. The pharyngeal ramus seemed to be atrophic distal to the lesion. A biopsy was taken from the lesion and histopathological findings proved the ...
Minshall GJ, Wright IM.To describe the presentation, clinical, ultrasonographic and endoscopic features associated with a defect in the tarsal sheath wall, to define the cavity created and to describe a method of treatment. Objective: So called 'false thoroughpins' can be caused by defects in the tarsal sheath wall creating a one way valve effect, removal of which could be therapeutic. Methods: Case records and diagnostic images of horses with synoviocoeles associated with the tarsal sheath were reviewed retrospectively and follow-up information obtained. Results: Synoviocoeles were diagnosed in 15 horses. All were ...
Byron CR, Benson BM, Karlin WM, Stewart AA.To report the use of a proximolateral endoscopic portal with a distolateral instrument portal for carpal retinaculum release in a horse clinically affected with carpal canal syndrome. Methods: Clinical report. Methods: A 4-year-old Thoroughbred female. Methods: Carpal canal syndrome secondary to traumatic suppurative tenosynovitis was treated by accessory carpal bone debridement and carpal retinaculum release using a tenoscopic approach to the carpal flexor synovial sheath through a proximolateral endoscope portal and a distolateral instrument portal. Results: Resolution of carpal sheath effus...
Puff C, Ohnesorge B, Wagels R, Baumgärtner W.A 4-month-old Warm-blooded colt presented with facial distorsion and an abnormal respiratory noise of 2 weeks' duration. A proliferative mass was found endoscopically and by computer tomography. Clinical differential diagnosis included cyst formation of the concha, malformation and neoplasia. Euthanasia was followed by post-mortem examination, which revealed a well-circumscribed, semi-solid, jelly like structure, measuring 14.5 x 9.0 x 12.0 cm, in the left posterior nasal cavity extending into the left frontal and maxillary sinus. Histologically, the mass consisted of trabeculae of woven bone,...
Muñoz JA, Marcoux M, Picandet V, Theoret CL, Perron MF, Lepage OM.Palatal sclerotherapy using sodium tetradecyl sulfate has been suggested as a treatment for dorsal displacement of the soft palate in young Standardbred horses. The present study evaluated histological and biomechanical changes in the equine soft palate following trans-endoscopic treatment with a low dose of this compound. Two horses were euthanased and examined at 2 weeks and at 1, 2, 4 and 6 months post-sclerotherapy, while two further horses served as untreated controls. The technique was easily performed in all cases without major complications. On histological examination there was no evi...
Banse HE, Piero FD, Andrews FM, Garcia-Abarca N, Watanabe TTN.To compare small intestinal inflammation with gastric inflammation in horses with and without equine gastric glandular disease (EGGD), we evaluated endoscopic, macroscopic, and microscopic findings of the glandular stomach and microscopic findings of the small intestine. Methods: 36 horses. Methods: Horses underwent endoscopy and were scored for EGGD. After euthanasia, stomachs were collected and macroscopically evaluated. Normal pyloric mucosa, glandular lesions, and small intestinal (duodenum, mid-jejunum, and ileum) samples were collected and processed for microscopic examination. Cellular ...
Massie SL, Léguillette R.Barrel racing involves sprinting through a cloverleaf pattern in under 20 s. The prevalence of upper airway obstructions (UAO) in barrel racers is unknown, thus a retrospective analysis of 164 client-owned horses referred for overground endoscopy (OGE) between 2014 and 2022 was performed. Referring complaints included respiratory noise, cough, epistaxis, behaviour (owner reported stress/anxiety, refusal to enter arena, excessive head shaking), and/or poor performance. Horses performed a standardized exercise test with low and high-speed components. Videoendoscopic recordings were systematical...
Webster A, Pezzanite L, Hendrickson D, Griffenhagen G.Equine practitioners frequently inject local anaesthetics (LA) intra-articularly in both diagnosis of lameness and for pain management intra- or post-operatively with synovial endoscopy. Recent reviews of the human and veterinary literature support the concept that chondrotoxicity of LA on joint tissues depends on the type of drug, dose administered, and duration of exposure. The purpose of this review is to summarise the current literature describing intra-articular local anaesthetic use, including both in vitro and in vivo studies, and to draw some comparisons to literature from other specie...
Lean NE, Franklin SH, Ahern BJ.To describe left recurrent laryngeal neurectomy (LRLn) performed under standing sedation and evaluate the effect of LRLn on upper respiratory tract function using a high-speed treadmill test (HST). We hypothesized that (1) unilateral LRLn could be performed in standing horses, resulting in ipsilateral arytenoid cartilage collapse (ACC); and (2) HST after LRLn would be associated with alterations in upper respiratory function consistent with dynamic ACC. Methods: 6 Thoroughbred horses. Methods: The horses were trained and underwent a baseline HST up to 14 m/s at 5% incline until fatigue. Evalua...
Laclaire AL, Manguin E, Tanquerel L.Effects of general anesthesia with controlled ventilation on the respiratory system have had limited evaluation in horses. A prospective observational study was performed with eleven client-owned horses undergoing elective surgery. Physical examination, auscultation with a rebreathing bag, complete blood cell count, lung ultrasound imaging, tracheal endoscopy imaging and transendoscopic tracheal wash were conducted before and 24 hours after anesthesia. Lung ultrasound imaging was also repeated just after recovery. A significant increase in blood neutrophil count between pre- and post-anesthesi...
Tavanaeimanesh H, Alinia Z, Sadeghian Chaleshtori S, Moosavian H, Mohebi Z, Daneshi M.During transportation many horses develop post-transportation infection, which can be life-threatening and end their sport career. Preventing mucus accumulation and inflammation during transportation is vital, emphasizing the need for effective strategies to enhance overall horse health welfare. Objective: Assess the impact of N-acetylcysteine (NAC) on mucus accumulation and inflammation in horses subjected to 18 hours of head confinement. Methods: Six healthy crossbred horses, 5.3 ± 2.1 years of age and weighing 387 ± 30 kg. Methods: Prospective placebo-controlled cross-over d...
Jeong S, Franklin SH, Van Eps AW, Lean N, Ahern BJ.Evaluate a prototype dynamic laryngoplasty system (DLPS) in horses; a feasibility study. Methods: 7 healthy Standardbred adult horses. Methods: This was an in vivo experimental study. Horses had a standing surgical procedure to induce complete laryngeal hemiplegia, which was subsequently treated using the dynamic laryngoplasty system (DLPS). Activation of the DLPS was achieved using an injection port exiting through the skin (n = 2) or a subcutaneous injection port (n = 5). For each horse, endoscopic examinations of the upper respiratory tract were performed preoperatively, intraoperatively, a...
Cieslak J, Mackowski M, Skrzetuska W, Fidos-Tama E, Siwinska N, Szczerbal I.A 9-year-old Thoroughbred mare with normal external genitalia and regular oestrus symptoms was gynecologically examined prior to insemination. This primary examination revealed the presence of a hypoplastic uterus and the lack of normal ovaries, and the mare was therefore subjected to more detailed diagnostics, including endocrinological, genetic, and clinical tests. Diagnostic imaging with the use of ultrasonography and endoscopy confirmed the underdevelopment of internal genitalia. Analysis of circulating sex hormones revealed very low concentrations of progesterone and oestradiol. Finally, ...
Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mi...
Hardwick JL, Ahern BJ, Franklin SH.To identify thoroughbred industry stakeholders' views on the yearling sales endoscopy in Australia. Methods: 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: Th...
Baldwin CM, Ireland JL, Barakzai SZ.There is no objective information reporting the effect of unilateral laser ventriculocordectomy (VeC) on arytenoid abduction or stability. Objective: To evaluate arytenoid stability and abduction in horses with severe recurrent laryngeal neuropathy (RLN) before and after unilateral laser VeC. Methods: Prospective cohort. Methods: Eight horses with grade C or D exercising laryngeal function that underwent unilateral laser VeC were included. Exercising endoscopy was performed before and ≥6 weeks after left-sided laser VeC. Arytenoid stability at maximal exercise was calculated by measuring t...
