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Döllinger M, Jakubaß B, Cheng H, Carter SJ, Kniesburges S, Aidoo B, Lee CH, Milstein C, Patel RR. Computational fluid dynamics of upper airway aerodynamics for exercise-induced laryngeal obstruction: A feasibility study. Laryngoscope Investig Otolaryngol 2023; 8:1294-1303. [PMID: 37899858 PMCID: PMC10601582 DOI: 10.1002/lio2.1140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 07/31/2023] [Indexed: 10/31/2023] Open
Abstract
Objective Use of computational fluid dynamic (CFD) simulations to measure the changes in upper airway geometry and aerodynamics during (a) an episode of Exercise-Induced Laryngeal Obstruction (EILO) and (b) speech therapy exercises commonly employed for patients with EILO. Methods Magnetic resonance imaging stills of the upper airway including the nasal and oral cavities from an adult female were used to re-construct three-dimensional geometries of the upper airway. The CFD simulations were used to compute the maximum volume flow rate (l/s), pressure (Pa), airflow velocity (m/s) and area of cross-section opening in eight planes along the vocal tract, separately for inhalation and exhalation. Results Numerical predictions from three-dimensional geometrical modeling of the upper airway suggest that the technique of nose breathing for inhalation and pursed lip breathing for exhalation show most promising pressure conditions and cross-sectional diameters for rescue breathing exercises. Also, if EILO is due to the constriction at the vocal fold level, then a quick sniff may also be a proper rescue inhalation exercise. EILO affects both the inspiratory and the expiratory phases of breathing. Conclusions A prior knowledge of the supraglottal aerodynamics and the corresponding upper airway geometry from CFD analysis has the potential to assist the clinician in choosing the most effective rescue breathing technique for optimal functional outcome of speech therapy intervention in patients with EILO and in understanding the pathophysiology of EILO on a case-by-case basis with future studies. Level of Evidence 4.
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Affiliation(s)
- Michael Döllinger
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Bernhard Jakubaß
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Hu Cheng
- Department of Psychological and Brain Sciences, Program of NeuroscienceIndiana UniversityBloomingtonIndianaUSA
| | - Stephen J. Carter
- Department of KinesiologySchool of Public Health, Indiana UniversityBloomingtonIndianaUSA
| | - Stefan Kniesburges
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Bea Aidoo
- Department of MedicineIndiana University School of MedicineBloomingtonIndianaUSA
| | - Chi Hwan Lee
- Department of Biomedical Engineering & Mechanical EngineeringPurdue UniversityWest LafayetteIndianaUSA
| | - Claudio Milstein
- Department of Otolaryngology‐Head & Neck Surgery, Cleveland Clinic Lerner and Case Western Reserve University Schools of MedicineHead and Neck Institute, Cleveland ClinicClevelandOhioUSA
| | - Rita R. Patel
- Department of Speech, Language, and Hearing Sciences and Department of Otolaryngology Head and Neck SurgeryIndiana UniversityBloomington/IndianapolisIndianaUSA
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Xi J, Si XA, Malvè M. Nasal anatomy and sniffing in respiration and olfaction of wild and domestic animals. Front Vet Sci 2023; 10:1172140. [PMID: 37520001 PMCID: PMC10375297 DOI: 10.3389/fvets.2023.1172140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 06/29/2023] [Indexed: 08/01/2023] Open
Abstract
Animals have been widely utilized as surrogate models for humans in exposure testing, infectious disease experiments, and immunology studies. However, respiratory diseases affect both humans and animals. These disorders can spontaneously affect wild and domestic animals, impacting their quality and quantity of life. The origin of such responses can primarily be traced back to the pathogens deposited in the respiratory tract. There is a lack of understanding of the transport and deposition of respirable particulate matter (bio-aerosols or viruses) in either wild or domestic animals. Moreover, local dosimetry is more relevant than the total or regionally averaged doses in assessing exposure risks or therapeutic outcomes. An accurate prediction of the total and local dosimetry is the crucial first step to quantifying the dose-response relationship, which in turn necessitates detailed knowledge of animals' respiratory tract and flow/aerosol dynamics within it. In this review, we examined the nasal anatomy and physiology (i.e., structure-function relationship) of different animals, including the dog, rat, rabbit, deer, rhombus monkey, cat, and other domestic and wild animals. Special attention was paid to the similarities and differences in the vestibular, respiratory, and olfactory regions among different species. The ventilation airflow and behaviors of inhaled aerosols were described as pertinent to the animals' mechanisms for ventilation modulation and olfaction enhancement. In particular, sniffing, a breathing maneuver that animals often practice enhancing olfaction, was examined in detail in different animals. Animal models used in COVID-19 research were discussed. The advances and challenges of using numerical modeling in place of animal studies were discussed. The application of this technique in animals is relevant for bidirectional improvements in animal and human health.
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Affiliation(s)
- Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, United States
| | - Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA, United States
| | - Mauro Malvè
- Department of Engineering, Public University of Navarre, Pamplona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
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Tilley P, Simões J, Sales Luis JP. Effects of a 15° Variation in Poll Flexion during Riding on the Respiratory Systems and Behaviour of High-Level Dressage and Show-Jumping Horses. Animals (Basel) 2023; 13:ani13101714. [PMID: 37238147 DOI: 10.3390/ani13101714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 04/29/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
From previous studies, the International Society for Equitation Science has advised that further research be conducted on the physiological/psychological effects of less-exacerbated poll flexion angles. We aimed to evaluate the effects of two riding poll flexion positions with a difference of only 15° on the respiratory systems and behaviour of horses through an evaluation of dynamic airway collapse via over-ground endoscopy, the pharyngeal diameter, pleural pressure, arterial oxygenation and lactate, HR/RR, and the occurrence of conflict behaviours. Twenty high-level dressage and twenty show-jumping horses underwent a 40 min ridden test at a ground angle of 85°; 3 weeks later, they underwent a ridden test at a 100° ground angle (the angle between the ground and the line from the forehead to the muzzle) and in a cross-over design. Using a mixed model for repeated measures, Wilcoxon/Friedman tests were carried out according to the experimental design and/or error normality. For both groups, at 100°, conflict behaviours and upper airway tract abnormalities were significantly more frequent, and the pleural pressure was higher, and the pharyngeal diameter was lower. At 85°, relaxation behaviours were significantly more frequent. Lactate was significantly higher at 100° only in the dressage horses. Compared to the first test at 85°, the HR/RR were significantly lower at the beginning of the second test (at 100°) but higher at the end. The significant differences identified in these dressage and show-jumping horses support the idea that an increase of just 15° in riding poll flexion can have negative effects on the respiratory system and behaviour of a horse and therefore on its welfare.
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Affiliation(s)
- Paula Tilley
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Lisbon, Portugal
| | - Joana Simões
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Lisbon, Portugal
- Equine Clinical Academic Department, Faculty of Veterinary Medicine, Lusófona University, 1749-024 Lisbon, Portugal
| | - José Paulo Sales Luis
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Lisbon, Portugal
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Tucker ML, Wilson DG, Bergstrom DJ, Carmalt JL. Computational fluid dynamic analysis of upper airway procedures in equine larynges. Front Vet Sci 2023; 10:1139398. [PMID: 37138910 PMCID: PMC10149674 DOI: 10.3389/fvets.2023.1139398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/24/2023] [Indexed: 05/05/2023] Open
Abstract
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). The first objective of this study was to generate a CFD model of an ex-vivo box model of ten different equine larynges replicating RLN and four therapeutic surgeries to compare the calculated impedance between these procedures for each larynx. The second objective was to determine the accuracy between a CFD model and measured airflow characteristics in equine larynges. The last objective was to explore the anatomic distribution of changes in pressure, velocity, and turbulent kinetic energy associated with the disease (RLN) and each surgical procedure performed. Methods Ten equine cadaveric larynges underwent inhalation airflow testing in an instrumented box while undergoing a concurrent computed tomographic (CT) exam. The pressure upstream and downstream (outlet) were measured simultaneously. CT image segmentation was performed to generate stereolithography files, which underwent CFD analysis using the experimentally measured outlet pressure. The ranked procedural order and calculated laryngeal impedance were compared to the experimentally obtained values. Results and discussion The CFD model agreed with the measured results in predicting the procedure resulting in the lowest post-operative impedance in 9/10 larynges. Numerically, the CFD calculated laryngeal impedance was approximately 0.7 times that of the measured calculation. Low pressure and high velocity were observed around regions of tissue protrusion within the lumen of the larynx. RLN, the corniculectomy and partial arytenoidectomy surgical procedures exhibited low pressure troughs and high velocity peaks compared to the laryngoplasty and combined laryngoplasty/corniculectomy procedures. CFD modeling of the equine larynx reliably calculated the lowest impedance of the different surgical procedures. Future development of the CFD technique to this application may improve numerical accuracy and is recommended prior to consideration for use in patients.
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Affiliation(s)
- Michelle L. Tucker
- Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- *Correspondence: Michelle L. Tucker
| | - David G. Wilson
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Donald J. Bergstrom
- Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - James L. Carmalt
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Tucker ML, Wilson DG, Reinink SK, Carmalt JL. Computed tomographic geometrical analysis of surgical treatments for equine recurrent laryngeal neuropathy. Am J Vet Res 2022; 83:443-449. [PMID: 35143413 DOI: 10.2460/ajvr.21.03.0040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
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. PROCEDURES While CT scans were performed, inhalation during exercise conditions was replicated for each of the following 5 conditions: laryngeal hemiplegia, left laryngoplasty with ventriculocordectomy, left laryngoplasty with ipsilateral ventriculocordectomy and arytenoid corniculectomy, corniculectomy, and partial arytenoidectomy for each larynx while CT scans were performed. Laryngeal impedance was calculated, and selected cross-sectional areas were measured along each larynx for each test. Measured areas and constriction characteristics were analyzed with respect to impedance using a multilevel, mixed-effects model. RESULTS Incident angle, entrance coefficient, outlet coefficient, friction coefficient, orifice thickness, and surgical procedure were significantly associated with upper airway impedance in the bivariable model. The multivariate model showed a significant influence of incident angle, entrance coefficient, and surgical procedure on impedance; however, the orifice thickness became nonsignificant within the model. CLINICAL RELEVANCE Laryngeal impedance was significantly associated with the entrance configuration for each procedure. This suggested that the equine upper airway, despite having a highly complex geometry, adheres to fluid dynamic principles applying to constrictions within pipe flow. These underlying flow characteristics may explain the clinical outcomes observed in some patients, and lead to areas of improvement in the treatment of obstructive upper airway disease in horses.
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Affiliation(s)
- Michelle L Tucker
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - David G Wilson
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Shawn K Reinink
- Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - James L Carmalt
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Kühnle C, Kümmerle JM, Parente EJ, Weishaupt MA. Laryngeal dyskinesia in a horse. EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- C. Kühnle
- Equine Department Vetsuisse Faculty University of Zurich Zurich Switzerland
| | - J. M. Kümmerle
- Equine Department Vetsuisse Faculty University of Zurich Zurich Switzerland
| | - E. J. Parente
- New Bolton Center University of Pennsylvania Philadelphia Pennsylvania USA
| | - M. A. Weishaupt
- Equine Department Vetsuisse Faculty University of Zurich Zurich Switzerland
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Byrne CA, Barakzai SZ. Equine emergency upper airway management. EQUINE VET EDUC 2020. [DOI: 10.1111/eve.12949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- C. A. Byrne
- Weipers Centre Equine Hospital University of Glasgow UK
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Tucker ML, Sumner D, Reinink SK, Wilson DG, Carmalt JL. Ex vivo evaluation of arytenoid corniculectomy, compared with three other airway interventions, performed on cadaveric equine larynges with simulated recurrent laryngeal neuropathy. Am J Vet Res 2020; 80:1136-1143. [PMID: 31763941 DOI: 10.2460/ajvr.80.12.1136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
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. Results for impedance, calculated from airflow and pressure changes, were compared between states for each larynx. Multivariable mixed-effects analysis controlling for repeated measures within larynx was performed to calculate the predicted mean impedance for each state. RESULTS Results indicated that tracheal adapter diameter, individual larynx properties, airway intervention, and relative laryngeal collapse affected laryngeal impedance. The LLP and LLPCOR interventions had the lowest impedance, whereas the COR and PA interventions did not differ substantially from the simulated left RLN state. Residual intraclass correlation of the model was 27.6 %. CONCLUSIONS AND CLINICAL RELEVANCE Although impedance was higher for the simulated left RLN with the COR intervention state than with the LLP intervention state, given the clinical success of PA for treating RLN in horses and the similar results for the COR and PA intervention states in the present study, the use of COR warrants further investigation. The residual interclass correlation suggested that individual laryngeal variation affected impedance and may have a clinical effect.
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Fretheim-Kelly ZL, Halvorsen T, Clemm H, Roksund O, Heimdal JH, Vollsæter M, Fintl C, Strand E. Exercise Induced Laryngeal Obstruction in Humans and Equines. A Comparative Review. Front Physiol 2019; 10:1333. [PMID: 31736771 PMCID: PMC6831747 DOI: 10.3389/fphys.2019.01333] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 10/07/2019] [Indexed: 12/03/2022] Open
Abstract
Dynamic obstructions of the larynx are a set of disorders that occur during exercise in equines and humans. There are a number of similarities in presentation, diagnosis, pathophysiology and treatment. Both equines and humans present with exercise intolerance secondary to dyspnea. During laryngoscopy at rest, the larynx appears to function normally. Abnormalities are only revealed during laryngoscopy at exercise, seemingly triggered by increased ventilatory demands, and quickly resolve after cessation of exercise. Lower airway disease (asthma being the most prevalent condition), cardiac disease and lack of fitness are the major differentials in both species. Laryngoscopic examination during exercise should be performed from rest to peak exertion to allow for a comprehensive diagnosis, including where the airway collapse begins, and thereafter how it progresses. Dynamic disorders with most visual similarity between humans and equines are: aryepiglottic fold collapse (both species); equine dynamic laryngeal collapse (DLC) relative to some forms of human combined supraglottic/glottic collapse; and epiglottic retroversion (both species). Quantitative grading techniques, such as airway pressure measurement, that have proven effective in veterinary research are currently being piloted in human studies. Conditions that appear visually similar are treated in comparable ways. The similarities of anatomy and certain types of dynamic collapse would suggest that the equine larynx provides a good model for human upper respiratory tract obstruction during exercise. Thus, close collaboration between veterinarians and medical personal may lead to further advancements in understanding pathophysiologic processes, and enhance the development of improved diagnostic tests and treatments that will benefit both species.
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Affiliation(s)
- Zoe Louise Fretheim-Kelly
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.,Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Thomas Halvorsen
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway.,Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway
| | - Hege Clemm
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Ola Roksund
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.,Faculty of Health and Social Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - John-Helge Heimdal
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway.,Department of Oral Surgery, Haukeland University Hospital, Bergen, Norway
| | - Maria Vollsæter
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Constanze Fintl
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Eric Strand
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Strand E, Össurardóttir S, Wettre KB, Fjordbakk CT. Alar fold resection in 25 horses: Clinical findings and effect on racing performance and airway mechanics (1998-2013). Vet Surg 2019; 48:835-844. [PMID: 31002392 DOI: 10.1111/vsu.13214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 03/11/2019] [Accepted: 04/01/2019] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To report clinical findings and performance in horses in which alar fold collapse (AFC) had been diagnosed and surgically treated and to assess form and degree of respiratory obstruction. STUDY DESIGN Retrospective case series. ANIMALS Twenty-one standardbreds, 2 coldblooded trotter racehorses, 1 thoroughbred, and 1 Icelandic horse. METHODS Alar fold collapse was diagnosed on the basis of continuous abnormal expiratory flutter noise coinciding with filling of the false nostrils during exercise on a high-speed treadmill that was alleviated by suturing the alar folds (AF) temporarily in a dorsal position. In 5 cases, nasopharyngeal airway pressures were assessed. Performance after complete, bilateral AF resection was assessed by reviewing career race records and by owner or trainer telephone interviews. RESULTS Horses presented because of poor performance, abnormal respiratory noise, or both. Additional dynamic disorders were identified in 12 of 21 standardbreds (intermittent dorsal displacement of the soft palate: n = 10; collapse of the roof of the nasopharynx: n = 2). Expiratory nasopharyngeal pressures seemed elevated in horses with AFC (range, +10.8 to +21.8 cm H2 O) compared with normal reference values. Dorsal fixation as well as complete surgical resection of the AF improved expiratory nasopharyngeal pressures to reported normal levels. At a mean of 68 months (range, 7-121) follow-up, 20 of 25 horses had competed after surgery, and 13 of 17 of the harness racehorses had established or improved their kilometer racing time marks. CONCLUSION Alar fold collapse caused mild to moderate expiratory obstruction and may have contributed to secondary nasopharyngeal collapse in this population. CLINICAL SIGNIFICANCE Complete surgical resection seems effective for treating AFC. Nasopharyngeal pressure measurement is a potential tool for confirming the diagnosis of AFC.
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Affiliation(s)
- Eric Strand
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Saga Össurardóttir
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Kjersti B Wettre
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Cathrine T Fjordbakk
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Ahern BJ, Lukas E, Lam K, Wilke E, Bertin FR, Van Eps A, Franklin S. Evaluation of a prototype dynamic laryngoplasty system in vitro with an equine vacuum airflow system. Vet Surg 2018; 48:173-179. [PMID: 30569487 DOI: 10.1111/vsu.13137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 04/09/2018] [Accepted: 05/29/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate a prototype dynamic laryngoplasty system (DLPS) in a static airflow model. STUDY DESIGN Experimental. SAMPLE POPULATION Ten equine larynges. METHODS The right arytenoid was fixed in abduction in all specimens. A left-sided laryngoplasty was performed with No. 2 Fiberwire and a FASTakII anchor. Each larynx was tested in a static airflow model. The system was adjusted to a flow rate of 55 L/s and prelaryngeal pressure of 12 mm Hg prior to testing in maximal arytenoid abduction. In phase 1, the left suture was loosened, shortened, and tested in 3-mm steps from 0 to 30 mm. In phase 2, the suture was tied with the DLPS in position at a target left-to-right quotient angle (LRQ) of 0.5. The DLPS was activated to target psi of 0, 25, and 50 for testing. Translaryngeal impedance (TLI), LRQ, cross-sectional areas (CSA), and resultant change in LRQ and CSA between, before, and during airflow testing were calculated. RESULTS In phase 1, TLI was reduced by suture shortening up to 6 mm (P = .001) but not by additional shortening (P > .05). In phase 2, activation of the DLPS reduced the TLI from 0 psi (0.43 ± 0.08 mm Hg/L/s) to 25 psi (0.16 ± 0.04 mm Hg/L/s, P < .001), but no further reduction was detected at maximal psi (P = .10). CONCLUSION Activation of the DLPS effectively reduced TLI. CLINICAL SIGNIFICANCE These results justify further investigation of the DLPS to assess its clinical applicability.
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Affiliation(s)
- Benjamin J Ahern
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Emily Lukas
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Kimberly Lam
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Emma Wilke
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Francois-Rene Bertin
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Andrew Van Eps
- Equine Specialist Hospital, School of Veterinary Science, University of Queensland, UQ Gatton Campus, Gatton, Queensland, Australia
| | - Samantha Franklin
- Equine Health and Performance Centre, University of Adelaide, Roseworthy, South Australia, Australia
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12
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Hostnik ET, Scansen BA, Zielinski R, Ghadiali SN. Quantification of nasal airflow resistance in English bulldogs using computed tomography and computational fluid dynamics. Vet Radiol Ultrasound 2017; 58:542-551. [PMID: 28718208 PMCID: PMC5597484 DOI: 10.1111/vru.12531] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 04/17/2017] [Accepted: 05/04/2017] [Indexed: 11/28/2022] Open
Abstract
Stenotic nares, edematous intranasal turbinates, mucosal swelling, and an elongated, thickened soft palate are common sources of airflow resistance for dogs with brachycephalic airway syndrome. Surgery has focused on enlarging the nasal apertures and reducing tissue of the soft palate. However, objective measures of surgical efficacy are lacking. Twenty-one English bulldogs without previous surgery were recruited for this prospective, pilot study. Computed tomography was performed using conscious sedation and without endotracheal intubation using a 128 multidetector computed tomography scanner. Raw multidetector computed tomography data were rendered to create a three-dimensional surface mesh model by automatic segmentation of the air-filled nasal passage from the nares to the caudal soft palate. Three-dimensional surface models were used to construct computational fluid dynamics models of nasal airflow resistance from the nares to the caudal aspect of the soft palate. The computational fluid dynamics models were used to simulate airflow in each dog and airway resistance varied widely with a median 36.46 (Pa/mm)/(l/s) and an interquartile range of 19.84 to 90.74 (Pa/mm)/(/s). In 19/21 dogs, the rostral third of the nasal passage exhibited a larger airflow resistance than the caudal and middle regions of the nasal passage. In addition, computational fluid dynamics data indicated that overall measures of airflow resistance may significantly underestimate the maximum local resistance. We conclude that computational fluid dynamics models derived from nasal multidetector computed tomography can quantify airway resistance in brachycephalic dogs. This methodology represents a novel approach to noninvasively quantify airflow resistance and may have utility for objectively studying effects of surgical interventions in canine brachycephalic airway syndrome.
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Affiliation(s)
- Eric T Hostnik
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, 43210
| | - Brian A Scansen
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, 43210
| | - Rachel Zielinski
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210
| | - Samir N Ghadiali
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210
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14
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Affiliation(s)
- G D Trope
- School of Animal and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
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Offord S, Tulloch LK, Franklin SH, Tremaine WH, Woodford N, Allen KJ. The effect of the laryngeal tie-forward procedure and soft palate cautery on nasopharyngeal diameter in horses. Vet Rec 2015; 176:19. [DOI: 10.1136/vr.102509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- S. Offord
- School of Veterinary Science; University of Bristol; Langford Bristol BS40 5DU UK
| | | | - S. H. Franklin
- School of Animal and Veterinary Sciences; University of Adelaide; Adelaide Australia
| | - W. H. Tremaine
- School of Veterinary Science; University of Bristol; Langford Bristol BS40 5DU UK
| | - N.S. Woodford
- Endell Veterinary Group; Salisbury Wiltshire SP5 3DG UK
| | - K. J. Allen
- Equine Sports Medicine Centre; School of Veterinary Science; University of Bristol; Langford Bristol BS40 5DU UK
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16
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Leutton JL, Lumsden JM. Dynamic respiratory endoscopic findings pre- and post laryngoplasty in Thoroughbred racehorses. Equine Vet J 2014; 47:531-6. [DOI: 10.1111/evj.12331] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 07/17/2014] [Indexed: 11/30/2022]
Affiliation(s)
- J. L. Leutton
- Perth Equine Hospital; Ascot Western Australia Australia
| | - J. M. Lumsden
- Randwick Equine Centre; Randwick New South Wales Australia
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17
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18
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Go L, Barton AK, Ohnesorge B. Evaluation of laryngeal function under the influence of various head and neck positions during exercise in 58 performance horses. EQUINE VET EDUC 2013. [DOI: 10.1111/eve.12091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L. Go
- Clinic for Horses; University of Veterinary Medicine Hannover; Hannover Germany
| | - A. K. Barton
- Clinic for Horses; University of Veterinary Medicine Hannover; Hannover Germany
- Equine Clinic; Department of Veterinary Medicine of Freie Universität Berlin; Berlin Germany
| | - B. Ohnesorge
- Clinic for Horses; University of Veterinary Medicine Hannover; Hannover Germany
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20
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Van Erck-Westergren E, Franklin SH, Bayly WM. Respiratory diseases and their effects on respiratory function and exercise capacity. Equine Vet J 2013; 45:376-87. [PMID: 23368813 DOI: 10.1111/evj.12028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 12/02/2012] [Indexed: 12/26/2022]
Abstract
Given that aerobic metabolism is the predominant energy pathway for most sports, the respiratory system can be a rate-limiting factor in the exercise capacity of fit and healthy horses. Consequently, respiratory diseases, even in mild forms, are potentially deleterious to any athletic performance. The functional impairment associated with a respiratory condition depends on the degree of severity of the disease and the equestrian discipline involved. Respiratory abnormalities generally result in an increase in respiratory impedance and work of breathing and a reduced level of ventilation that can be detected objectively by deterioration in breathing mechanics and arterial blood gas tensions and/or lactataemia. The overall prevalence of airway diseases is comparatively high in equine athletes and may affect the upper airways, lower airways or both. Diseases of the airways have been associated with a wide variety of anatomical and/or inflammatory conditions. In some instances, the diagnosis is challenging because conditions can be subclinical in horses at rest and become clinically relevant only during exercise. In such cases, an exercise test may be warranted in the evaluation of the patient. The design of the exercise test is critical to inducing the clinical signs of the problem and establishing an accurate diagnosis. Additional diagnostic techniques, such as airway sampling, can be valuable in the diagnosis of subclinical lower airway problems that have the capacity to impair performance. As all these techniques become more widely used in practice, they should inevitably enhance veterinarians' diagnostic capabilities and improve their assessment of treatment effectiveness and the long-term management of equine athletes.
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21
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Barakzai SZ, Cheetham J. Endoscopic examination of exercising horses: Effects on diagnosis and treatment of upper respiratory tract disorders. Equine Vet J 2012; 44:501-3. [DOI: 10.1111/j.2042-3306.2012.00625.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Cheetham J, Regner A, Jarvis JC, Priest D, Sanders I, Soderholm LV, Mitchell LM, Ducharme NG. Functional electrical stimulation of intrinsic laryngeal muscles under varying loads in exercising horses. PLoS One 2011; 6:e24258. [PMID: 21904620 PMCID: PMC3164194 DOI: 10.1371/journal.pone.0024258] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 08/07/2011] [Indexed: 11/22/2022] Open
Abstract
Bilateral vocal fold paralysis (BVCP) is a life threatening condition and appears to be a good candidate for therapy using functional electrical stimulation (FES). Developing a working FES system has been technically difficult due to the inaccessible location and small size of the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle. A naturally-occurring disease in horses shares many functional and etiological features with BVCP. In this study, the feasibility of FES for equine vocal fold paralysis was explored by testing arytenoid abduction evoked by electrical stimulation of the PCA muscle. Rheobase and chronaxie were determined for innervated PCA muscle. We then tested the hypothesis that direct muscle stimulation can maintain airway patency during strenuous exercise in horses with induced transient conduction block of the laryngeal motor nerve. Six adult horses were instrumented with a single bipolar intra-muscular electrode in the left PCA muscle. Rheobase and chronaxie were within the normal range for innervated muscle at 0.55±0.38 v and 0.38±0.19 ms respectively. Intramuscular stimulation of the PCA muscle significantly improved arytenoid abduction at all levels of exercise intensity and there was no significant difference between the level of abduction achieved with stimulation and control values under moderate loads. The equine larynx may provide a useful model for the study of bilateral fold paralysis.
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Affiliation(s)
- Jon Cheetham
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.
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23
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Passman SN, Cheetham J, Bonassar LJ, Ducharme NG, Rawlinson JJ. Biomechanical characterisation of equine laryngeal cartilage. Equine Vet J 2011; 43:592-8. [PMID: 21545513 DOI: 10.1111/j.2042-3306.2010.00315.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
REASONS FOR PERFORMING THE STUDY Upper airway obstruction is a common problem in the performance horse as the soft tissues of the larynx collapse into the airway, yet there is a paucity of information on biomechanical properties for the structural cartilage components. OBJECTIVE To measure the geometry and compressive mechanical properties of the hyaline cartilage to improve understanding of laryngeal function and morphology. METHODS A total of 11 larynges were harvested from Thoroughbred and Standardbred racehorses. During gross dissection, linear dimensions of the cricoid were obtained. From both the cricoid and arytenoid, specimens were cored to obtain 6 mm disc samples from 3 sites within the dorsal cricoid (caudal, middle and rostral) and 2 central sites in the arytenoids (inner, outer). The specimens were mechanically tested using radial confined compression to calculate the aggregate modulus and permeability of the tissue. The biomechanical data were analysed using a nested mixed effects model. RESULTS Geometrically, the cricoid has relatively straight walls compared to the morphology of human, ovine and canine larynges. There were significant observations of higher modulus with increasing age (0.13 MPa per year; P = 0.007) and stiffer cricoid cartilage (2.29 MPa) than the arytenoid cartilage (0.42 MPa; P<0.001), but no difference was observed between the left and right sides. Linear contrasts showed that the rostral aspect (2.51 MPa) of the cricoid was 20% stiffer than the caudal aspect (2.09 MPa; P = 0.025), with no difference between the arytenoid sites. CONCLUSIONS The equine larynx is a well supported structure due to both the geometry and material properties of the cricoid cartilage. The hyaline structure is an order of magnitude higher in compressive modulus compared to the arytenoids and other hyaline-composed tissues. POTENTIAL RELEVANCE These characterisations are important to understand the biomechanics of laryngeal function and the mechanisms involved with surgical interventions.
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Vanschandevijl K, Nollet H, Vonck K, Raedt R, Boon P, Roost D, Martens A, Deprez P. Functional electrical stimulation of the left recurrent laryngeal nerve using a vagus nerve stimulator in a normal horse. Vet J 2010; 189:346-8. [PMID: 20724182 DOI: 10.1016/j.tvjl.2010.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 07/01/2010] [Accepted: 07/08/2010] [Indexed: 11/19/2022]
Abstract
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 sustained abduction of the arytenoid was obtained with a stimulation frequency of 25 Hz and intensity of 1 mA with a pulse width of 250 μs.
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Affiliation(s)
- Katleen Vanschandevijl
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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Rakesh V, Ducharme NG, Cheetham J, Datta AK, Pease AP. Implications of different degrees of arytenoid cartilage abduction on equine upper airway characteristics. Equine Vet J 2009; 40:629-35. [PMID: 19165931 DOI: 10.2746/042516408x330329] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASON FOR PERFORMING STUDY The necessary degree of arytenoid cartilage abduction (ACA) to restore airway patency at maximal exercise has not been determined. OBJECTIVES Use computational fluid dynamics modelling to measure the effects of different degrees of ACA on upper airway characteristics of horses during exercise. HYPOTHESIS 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; and 75% cross-sectional area of the rima glottis. The right arytenoid cartilage was maximally abducted. Two models were assumed: Model 1: no compensation of airway pressures; and Model 2: airway pressure compensation occurs to maintain peak airflow. The cross-sectional pressure and velocity distributions for turbulent flow were studied at peak flow and at different positions along the airway. RESULTS Model 1: In the absence of a change in driving pressure, 12 and 25% reductions in cross-sectional area of the larynx resulted in 4.11 and 5.65% reductions in peak airflow and 3.68 and 5.64% in tidal volume, respectively, with mild changes in wall pressure. Model 2: To maintain peak flow, a 6.27% increase in driving tracheal pressure was required to compensate for a cross-sectional reduction of 12% and a 13.63% increase in driving tracheal pressure was needed for a cross-sectional area reduction of 25%. This increase in negative driving pressure resulted in regions with low intraluminal and wall pressures, depending on the degree of airway diameter reduction. CONCLUSION Assuming no increase in driving pressure, the decrease in left ACA reduced airflow and tidal volume. With increasing driving pressure, a decrease in left ACA changed the wall pressure profile, subjecting the submaximally abducted arytenoid cartilage and adjacent areas to airway collapse. CLINICAL RELEVANCE The surgical target of ACA resulting in 88 % of maximal cross-sectional area seems to be appropriate.
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Affiliation(s)
- V Rakesh
- Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, North Carolina 27606, USA
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Robinson NE, Zhuang M. Custom-designed airway surgery for the horse: a dream that may become reality. Equine Vet J 2008; 40:195-7. [PMID: 18442960 DOI: 10.2746/042516408x298263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- N E Robinson
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA
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