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OBJECTIVE To characterize the anatomic location of the esophageal ostium relative to the rima glottidis in adult Labrador Retrievers with the use of CT. ANIMALS 98 CT scans of 75 adult Labrador Retrievers. PROCEDURES A search of the medical records database identified records of Labrador Retrievers that underwent CT of the head and neck between January 1, 2015, and December 31, 2018. Evaluators, blinded to each other's results, reviewed CT images and measured esophageal area at the level of the rima glottidis. For each dog, the left esophageal percentage (LEP) was calculated as the esophageal area left of the rima glottidis midline divided by the overall esophageal area at that level. Variables (age, sex, patient position, intubation status, and maxillary support during CT) were evaluated for association with LEP. The CT images of dogs that had multiple scans were assessed for within-patient variance. RESULTS Mean LEP was 56.2 ± 18.1% for all dogs. Only right lateral recumbency was significantly associated with LEP, with a lower LEP for dogs positioned in right lateral recumbency (42.4 ± 12.7%), compared with left lateral (63.0 ± 7.4%) or sternal (57.3 ± 18.8%) recumbency. No association was detected between LEP and other variables assessed. Eleven dogs had multiple CT scans; within-patient variance for LEP was ± 26.6%. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that, although most dogs had an LEP > 50%, the esophageal ostium was fairly centrally located in most dogs and may be more mobile than previously thought. Additional research is warranted to assess this mobility and whether the esophageal ostium location, relative to the larynx, affects the incidence of aspiration pneumonia in dogs undergoing surgical treatment for geriatric-onset laryngeal paralysis and polyneuropathy.

Objective 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. Study design Ex-vivo experimental study. Sample population 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 (cmH2 0/L/s) were determined and compared between LP constructs before and after cycling. Results The mean CSA of the rima glottidis of the modified toggle LP constructs was 15.2 ± 2.6 cm2 before and 14.7 ± 2.6 cm2 after cyclic loading, and the mean CSA of the rima glottidis of the standard LP constructs was 16.4 ± 2.9 cm2 before and 15.7 ± 2.8 cm2 after cyclic loading. The modified toggle LP constructs had similar peak translaryngeal impedance before and after cyclic loading (p = .13); however, the standard LP constructs had higher peak translaryngeal impedance after cyclic loading (p = .02). Conclusion The modified toggle and standard LP constructs had comparable airway mechanics in an ex-vivo model. Clinical significance Further investigation is warranted to determine the extent to which the modified toggle LP technique restores normal airway function in horses with RLN.

Summary Objectives Awake injection medialization laryngoplasty is one of the most common therapeutic procedures done by laryngologists in the office or at the bedside. Complications of injection needle fracture are rarely reported. Methods This is a case report of a 59-year-old male inpatient who developed left vocal fold immobility with significant glottic insufficiency after pneumonectomy for a large left-sided lung cancer. During bedside injection medialization using thyrohyoid approach, the 25 G needle fractured at the hub and was embedded partly in pre-epiglottic space and partly extending over rima glottidis. Results Fractured needle was successfully retrieved at the bedside with an endoscopic biopsy forcep using flexible bronchoscope. Conclusion It is imperative to be aware of rare complications of routine procedures like injection laryngoplasty so they can be managed timely and effectively.

Recently, an electrical stimulation of the paralyzed muscle, as a potential therapy for restoring function of a denervated muscle system, has been debated as an innovative treatment in the management of patients with laryngeal paralysis. Numerous studies in acute and chronic animal models have demonstrated that electrical stimulation of the paralyzed posterior cricoarytenoideus muscle (PCA) offers an approach to induce vocal fold abduction and restore ventilation through the glottis. The study aims to test applicability of the controlled opening of the rima glottides via direct electrical stimulation of the posterior cricoarytenoideus muscle. We developed for this purpose a novel instrument system for the controlled larynx nerve stimulation. An acute experiment on the 4 years old pig showed effectiveness of the engineered stimulator. The controlled opening of rima glottidis of both posterior cricoarytenoid muscles and afterwards of both PCA muscle contraction were observed as a result of the electrical stimulation with the applied current in the range of 0.1–3 mA and pulse width of 1 ms and 10 ms. Performed research indicates a large potential of the novel nerve stimulator for the human larynx stimulation.

The laryngoscopic examination remains the gold standard in the perioperative evaluation of the mobility of the vocal folds in patients with goiter. During the COVID-19 pandemic, many medical procedures, including laryngoscopy are optimized in terms of epidemiological safety. Therefore, it seems deeply justified to implement methods like i.e. ultrasound or MRI which can provide the diagnostic information usually obtained via laryngoscopic examination. Aim of the study: To determine the value of dynamic MRI examination in the 1.5 T field in the assessment of the mobility of vocal folds in patients with goiter compared to healthy people and in relation to ultrasound examinations and routine laryngoscopy. Materials and methods: 35 healthy volunteers and 44 patients with goiter were subjected to videolaryngoscopy, dynamic examinations of the vocal folds during respiration and phonation using ultrasound and the MRI sequences: generic gradient echo (GRE) and true fast imaging with steady-state precession (TRUFI). The qualitative and quantitative data were analyzed, i.e. the angles of deviation from the midline of the vocal folds and the area of the right and left rima glottidis compartments. Results: No statistically significant differences were found between the groups of healthy volunteers and patients with goiter in the values of the angles of deviation of the vocal folds with the use of ultrasound and two MRI dynamic sequences - GRE and TRUFI. There were also no statistically significant differences in the areas of the rima glottidis compartments between these two groups with the use of two MRI dynamic sequences - GRE and TRUFI. Among the analyzed parameters, the maximum size of each rima glottidis compartment was the only one to show features of sexual dimorphism and was significantly higher in men (GRE p < 0.001 and TRUFI p = 0.001). There was no correlation between the size of the minimum and maximum rima glottidis compartment and the total volume of the thyroid lobes in patients with goiter for the GRE and TRUFI sequences. Conclusions: MRI is a promising tool for the objective assessment of the mobility of the vocal folds in patients with goiter, as well as for the qualification for treatment and monitoring its effects. It is particularly important during an epidemiological emergency due to its safety compared to laryngoscopy. The presence of the goiter and its volume do not limit the possibility of performing dynamic imaging studies of the vocal folds and do not affect the surface area of the glottis.

An omega-shaped epiglottis may present as a foreign body sensation in the throat in childhood, or it may accompany laryngomalacia. Airway obstruction may occur due to the morphology of the epiglottal deformity. The literature has limited information on cases with manifestation in the geriatric population. This report concerns a 72-year-old male who presented complaining of hoarseness for 3 months. The patient had a 40-pack/year history of cigarette smoking. The patient was taken to the operating room for laryngeal biopsy. Following anesthesia induction, the initial attempt at endotracheal intubation by direct laryngoscopy with a Macintosh-type blade was unsuccessful because the rima glottidis was located significantly superiorly and anteriorly. A second attempt was performed by videolaryngoscopy. The endotracheal intubation was successful during this attempt using a 6.5-mm spiral endotracheal tube stylet. No airway complications emerged.

Background There is limited knowledge of the breathing strategy and impact on the patency of the upper respiratory tract (URT) in swimming horses. Objectives To describe the respiratory responses and endoscopic appearance of the URT during tethered swimming in horses. Study design Prospective descriptive study. Methods Ten race-fit horses, with no history of URT obstruction, were examined during tethered swimming. Endoscopic examination, heart rate, sound recordings and above and below water video recordings were obtained. Plasma lactate concentration was measured before and 5 min after swimming and tracheal endoscopy was performed 30 min after exercise to assess for presence of blood or mucus. Four horses also underwent endoscopy during exercise on the track. Results Mean (±s.d.) breathing frequency was 28 ± 5 breaths/min during swimming, with a brief inspiration (mean ± s.d. TI = 0.51 ± 0.08 s), followed by a period of apnoea (1.59 ± 0.53 s) and then a short, forced expiration (TE = 0.42 ± 0.5 s). During apnoea all horses exhibited complete collapse of the URT including closure of the external nares, nasopharynx and rima glottidis (with bilateral adduction of the arytenoid cartilages and vocal folds) and, in two horses, epiglottic retroversion. No horses had URT collapse during overground exercise. Locomotor-respiratory coupling was not observed during swimming. Median (IQR) plasma lactate post swim was 4.71 mmol/L (2.08-8.09 mmol/L) vs 0.68 mmol/L (0.65-0.71 mmol/L) preswim. Post swim endoscopy revealed grade 1 exercise-induced pulmonary haemorrhage (EIPH) in 2 horses. Median mucus grade was 1 (range 0-3). Main limitations Overground endoscopy was not performed in all horses. Conclusions Horses experienced complete URT collapse associated with post inspiratory apnoea when swimming. The reason for this is unknown but may be to aid buoyancy or associated with the mammalian dive response - a survival reflex to preserve oxygen stores and prevent water entering the lungs.

Background: Rima glottidis and cricoid cartilage are important parts for laryngealpassage. However, their complex anatomical organizations give rise to occursome difficulties during intubation or surgeries. Therefore, these anatomicalstructures have great risk of damage during these procedures. The main aim ofthis study is to evaluate detailed morphometric properties of these criticalparts of the larynx.Methods:In this study, 74 female and 76 male patients’, without any pathology in theirlaryngeal and neck regions, computed tomography images were examined,retrospectively. Anteroposterior diameter of the supraglottic regionimmediately above the vocal folds, anterior angle of the vocal folds,transverse diameter of the rima glottidis and anteroposterior and transversediameters of the cricoid cartilage were measured using Osirix-Lite version 9. Results:Transverse diameter of the cricoid cartilage was found less than 1 cm, however,the transverse diameter of the rima glottidis was significantly smaller. Allvariables except for anterior angle of the vocal folds were higher in men thanwomen. Conclusions: The transverse diameter of the rima glottidis was the narrowest partof the laryngeal passage. The physicians should be aware of this part of thelarynx besides the cricoid cartilage during endotracheal tubeadministrations. Keywords:Adult airway, computed tomography imaging, cricoid cartilage, larynx, vocalfolds., Amaç: Rima glottidis ve cartilago cricoidea larynx geçişinin önemlikısımlarıdır. Bununla birlikte, karmaşık anatomik yapılar olmaları sebebiyleentübasyon veya cerrahi sırasında bazı güçlüklere yol açabilirler. Bu sebeple,bu işlemler sırasında, bu anatomik yapılar, istenmeyen yaralanmalar açısındanoldukça büyük bir risk altındadırlar. Çalışmamızın amacı, larynx’in bu önemliparçalarının morfometrelerinin detaylı olarak incelenmesidir. Materyal veMetod: Bu çalışmada, larynx veboyun bölgelerinde herhangi bir patoloji olmayan 74 kadın ve 76 erkek hastayaait bilgisayarlı tomografi görüntüleri retrospektif olarak incelendi. Plicavocalis’in hemen üzerinde kalan supraglottic bölgenin anteroposterior çapı,plica vocalis’lerin anterior birleşme açısı, rima glottidis’in transvers çapıve cartilago cricoidea’nın anteroposterior ve transvers çapları Osirix-Liteversion 9 yazılımı kullanılarak ölçüldü. Bulgular: Cartilago cricoidea’nın transvers çapı 1 cm'den az bulundu, ancak rimaglottidis'in transvers çapı cartilago cricoidea’nın transvers çapından anlamlıderecede daha küçüktü. Plica vocalis’in anterior açısı dışındaki tümdeğişkenler erkeklerde kadınlardan daha yüksekti.Sonuç: Rima glottidis’in transvers çapı larynx geçişinin en dar kısmıydı.Endotrakeal tüp uygulamaları sırasında, uygulamayı yapacak olan hekimlercartilago cricoidea’nın yanı sıra larynx’in bu kısmının da farkında olmalıdır. AnahtarKelimeler: Erişkin solunum yolları,bilgisayarlı tomografi, cartilago cricoidea, larynx, plica vocalis.

To assess laryngeal function in normal dogs administered isoflurane following partial clearance of alfaxalone or propofol.Randomized experimental crossover study.A group of 12 purpose-bred, male Beagle dogs.Dogs were randomly assigned to one of two treatments: alfaxalone-isoflurane (ALF-ISO) or propofol-isoflurane (PRO-ISO) and anesthetized for three video laryngoscopy examinations. The alternate treatment occurred after ≥ 14 days interval. Examinations were performed after induction of anesthesia (LS-A), after 20 minutes of breathing isoflurane via a facemask (LS-B) and after a further 20 minutes of isoflurane (LS-C). Parameters of objective laryngeal function included inspiratory rima glottidis surface area (RGSA-I), expiratory rima glottidis surface area (RGSA-E) and % RGSA increase, calculated from three consecutive respiratory cycles in the final 15 seconds of each video laryngoscopy examination. The % RGSA increase was calculated using [(RGSA-I - RGSA-E)/RGSA-E] × 100. Subjective laryngeal function was evaluated independently by two experienced surgeons blinded to treatment.The % RGSA increase within each treatment was greater for LS-B and LS-C than for LS-A (ALF-ISO: p = 0.03, PRO-ISO: p =0.001). There was no difference within each treatment from LS-B compared with LS-C. RGSA-I increased within each treatment from LS-A to both LS-B and LS-C (ALF-ISO: p = 0.002) and to LS-C (PRO-ISO: p = 0.006). Subjective laryngeal function scores improved from LS-A to LS-C.Laryngeal function improved from postinduction examination following either 20 or 40 minutes of anesthesia with isoflurane via facemask. This study demonstrates that isoflurane may have a lesser effect on arytenoid abduction activity compared with more commonly used intravenous induction anesthetics (alfaxalone and propofol).

Although, calf diphtheria and necrotic laryngitis are common infections in the oral cavity’s soft tissues, arytenoid chondritis is addressed as a serious but rarely diagnosed complication in cattle. This paper aimed to describe clinical, laboratory, imaging, and pathological findings in two calves with arytenoid chondritis. A 2-month-old Jersey calf and a 3-month-old Girolando calf presented 40-days history of respiratory distress. In the former, oral endoscopy revealed enlarged and immobile arytenoids with major involvement of the left arytenoid, causing severe distortion and partial obstruction of the rima glottidis. In the latter, latero-lateral radiography of the head revealed radiolucent areas and thickening at the level of the larynx to the dorsal trachea. Pathological examination of one calf showed neutrophilic multifocal inflammatory infiltrate and areas of necrosis in the cricoarytenoid cartilage, surrounded by abscessation. Definitive diagnosis of arytenoid chondritis in these two calves was established on the basis of clinical, laboratory, imaging (endoscopy and radiography), and pathological findings. Daily and careful observation of the herds and the use of ancillary diagnostic methods allowed the early diagnosis of the disease, and accurate diagnosis can improve prognosis and increase treatment success rate. RESUMO: Embora a difteria em bezerros e a laringite necrótica sejam infecções comuns nos tecidos moles da cavidade oral, a condrite aritenoide é considerada uma complicação grave, mas raramente diagnosticada em bovinos. Este trabalho tem como objetivo descrever os achados clínicos, laboratoriais, de imagem e patológicos em duas bezerras apresentando condrite aritenoide. Uma bezerra Jersey de dois meses de idade e uma bezerra Girolando de três meses de idade apresentavam dificuldades respiratórias por 40 dias. Na primeira, a endoscopia oral revelou aritenoides aumentadas e imóveis, com grande envolvimento da aritenoide esquerda, causando distorção grave e obstrução parcial de rima glottidis. Na segunda, a radiografia látero-lateral da cabeça revelou áreas radioluscentes e espessamento ao nível da laringe até a traqueia dorsal. O exame patológico de uma bezerra revelou infiltrado inflamatório multifocal neutrofílico e áreas de necrose na cartilagem cricoaritenóide, circundadas por abscessos. O diagnóstico definitivo de condrite aritenoide nessas duas bezerras foi estabelecido com base nos achados clínicos, laboratoriais, de imagem (endoscopia e radiografia) e patológicos. O monitoramento diário e minucioso dos rebanhos e o uso de métodos auxiliares de diagnóstico permitem o diagnóstico precoce da enfermidade, sendo que o diagnóstico preciso pode melhorar o prognóstico e aumentar a taxa de sucesso do tratamento.

Objective To determine the influence of propofol or methohexital, with and without doxapram, on the examination of laryngeal function in dogs. Study design Experimental study. Animals Forty healthy dogs randomly assigned to 4 groups: propofol with saline (n = 10), propofol with doxapram (n = 10), methohexital with saline (n = 10), or methohexital with doxapram (n = 10). Methods Propofol and methohexital were administered to effect. Investigators examined laryngeal function (initial) simultaneously with video laryngoscopy. Doxapram or saline was administered, and laryngeal function was reevaluated (second). Laryngeal motion, quality of laryngeal exposure, and the degree of swallowing, laryngospasm, and jaw tone were scored at each evaluation. Adverse events were recorded. Initial and second videos were evaluated by a masked observer, and still images obtained from both evaluations were evaluated for change in rima glottidis size by 2 masked observers. Results Administration of doxapram and saline was delayed with propofol (P = .001). Laryngeal function did not differ between dogs receiving propofol or methohexital, irrespective of doxapram administration. Doxapram improved breathing scores in both groups (P

Background Unilateral ventriculocordectomy (VeC) is frequently performed, yet objective studies in horses with naturally occurring recurrent laryngeal neuropathy (RLN) are few. Objectives To evaluate respiratory noise and exercising overground endoscopy in horses with grade B and C laryngeal function, before and after unilateral laser VeC. Study design 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-examination 6-8 weeks post-operatively when exercising endoscopy and sound recordings were repeated. Exercising endoscopic findings were recorded, including the degree of arytenoid stability. Quantitative measurement of left-to-right quotient angle ratio (LRQ) and rima glottidis area ratio (RGA) were performed pre- and post-operatively. Sound analysis was performed, and measurements of the energy change in F1, F2 and F3 formants between pre- and post-operative recordings were made and statistically analysed. Results Three grade B and seven grade C horses were included; 6/7grade C horses preoperatively had bilateral vocal fold collapse (VFC) and 5/7 had mild right-sided medial deviation of the ary-epiglottic fold (MDAF). Right VFC and MDAF was still present in these horses post-operatively; grade B horses had no other endoscopic dynamic abnormalities post-operatively. Sound analysis showed significant reduction in energy in formant F2 (P = 0.05) after surgery. Main limitations The study sample size was small and multiple dynamic abnormalities made sound analysis challenging. Conclusions RLN-affected horses have reduction in sound levels in F2 after unilateral laser VeC. Continuing noise may be caused by other ongoing forms of dynamic obstruction in grade C horses. Unilateral VeC is useful for grade B horses based on endoscopic images. In grade C horses, bilateral VeC, right ary-epiglottic fold resection ± laryngoplasty might be a better option than unilateral VeC alone. The Summary is available in Portuguese - see Supporting Information.

To compare the effects of alfaxalone and propofol, with and without acepromazine and butorphanol followed by doxapram, on laryngeal motion and quality of laryngeal examination in dogs.Randomized, crossover, blinded study.Ten female Beagle dogs, aged 11-13 months and weighing 7.2-8.6 kg.The dogs were administered four intravenous (IV) treatments: alfaxalone (ALF), alfaxalone+acepromazine and butorphanol (ALF-AB), propofol (PRO) and propofol+AB (PRO-AB). AB doses were standardized. Dogs were anesthetized 5 minutes later by administration of alfaxalone or propofol IV to effect. Arytenoid motion during maximal inspiration and expiration was captured on video before and after IV doxapram (0.25 mg kgA 20% increase in RGSA was the minimal arytenoid motion that was detectable. RGSA was significantly less in ALF before doxapram compared with all other treatments. A20% increase in RGSA was measured in eight of 10 dogs in PRO and in all dogs in ALF before doxapram. After doxapram, RGSA was significantly increased for PRO and ALF; however, 20% of dogs in PRO and 50% of dogs in ALF still had20% increase in RGSA. A20% increase in RGSA was measured in five of 10 dogs in PRO-AB and ALF-AB before doxapram. All dogs in PRO-AB and ALF-AB with20% increase in RGSA before doxapram had ≥20% increase in RGSA after doxapram. Examination quality was significantly better in PRO-AB and ALF-AB.The use of acepromazine and butorphanol improved the quality of laryngeal examination. Any negative impact on arytenoid motion caused by these premedications was overcome with doxapram. Using either propofol or alfaxalone alone is not recommended for the evaluation of arytenoid motion.

Objective To evaluate the effect of two levels of partial neuromuscular block (NMB) on arytenoid abduction, tidal volume (VT) and peak inspiratory flow (PIF) in response to a hypercarbic challenge in anesthetized dogs. Study design Prospective laboratory study. Animals Eleven healthy male Beagle dogs aged 3–5 years. Methods Dogs were anesthetized with propofol and dexmedetomidine infusions. The rima glottidis was observed via an endoscope placed through a laryngeal mask airway. Atracurium infusion was titrated to obtain two levels of partial NMB. The normalized glottal gap area (NGGA; glottal gap area normalized to height squared of rima glottidis) at peak inspiration during a hypercarbic challenge (10% CO2 inspired for 1 minute) was measured at baseline, during mild [train-of-four (TOF) ratio 0.4–0.6] and shallow (TOF ratio 0.7–0.9) NMB, and 30 minutes after spontaneous recovery from NMB. The VT and PIF were measured at the same time points and compared using anova for repeated measures and Tukey’s post hoc tests. Results The NGGA and VT were significantly lower than baseline during both levels of partial NMB with no difference between mild and shallow NMB (p Conclusions and clinical relevance The NGGA and VT at peak inspiration in response to a hypercarbic challenge were reduced during partial NMB block, with decreased abduction of the arytenoid cartilages. This dysfunction was present even at shallow levels of NMB.

Purpose: To verify the value of dynamic magnetic resonance imaging (MRI) sequences, fast field echo (FFE), and balanced gradient echo (true fast imaging with steady-state free precession - TRUFI) in the evaluation of vocal fold mobility in healthy volunteers, against ultrasound examination (US) as the reference test. Material and methods: Vocal fold mobility in 35 healthy volunteers (age 20-59 years, 20 women and 15 men) with no history of laryngeal disorders and neck surgeries was determined by means of US and MRI during normal breathing and phonation of the "hiiii" sound. US images were used to determine the glottic angles. During MRI two dynamic sequences, fast field echo and balanced gradient echo, were applied to determine the minimum and maximum values of the glottic angles, along with the rima glottidis area, separately for the right and left compartments. Due to differences in larynx anatomy, the abovementioned parameters were analysed separately for women and men. Results: No significant differences were observed between the glottic angle values obtained during US and dynamic MRI (FFE and TRUFI sequences). Regardless of the dynamic MRI sequence used, a positive correlation was found between the maximum values of glottic angle and the rima glottidis area. This correlation was strong and statistically significant among men, but not in women. Conclusions: Dynamic MRI of vocal folds using FFE and TRUFI sequence is an accurate method for the objective evaluation of rima glottidis width.

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by a combination of autonomic failure, cerebellar ataxia, and parkinsonism. Laryngeal stridor is an additional feature for MSA diagnosis, showing a high diagnostic positive predictive value, and its early occurrence might contribute to shorten survival. A consensus definition of stridor in MSA is lacking, and disagreement persists about its diagnosis, prognosis, and treatment. An International Consensus Conference among experts with methodological support was convened in Bologna in 2017 to define stridor in MSA and to reach consensus statements for the diagnosis, prognosis, and treatment. Stridor was defined as a strained, high-pitched, harsh respiratory sound, mainly inspiratory, occurring only during sleep or during both sleep and wakefulness, and caused by laryngeal dysfunction leading to narrowing of the rima glottidis. According to the consensus, stridor may be recognized clinically by the physician if present at the time of examination, with the help of a witness, or by listening to an audio recording. Laryngoscopy is suggested to exclude mechanical lesions or functional vocal cord abnormalities related to different neurologic conditions. If the suspicion of stridor needs confirmation, drug-induced sleep endoscopy or video polysomnography may be useful. The impact of stridor on survival and quality of life remains uncertain. Continuous positive airway pressure and tracheostomy are both suggested as symptomatic treatment of stridor, but whether they improve survival is uncertain. Several research gaps emerged involving diagnosis, prognosis, and treatment. Unmet needs for research were identified.

Objective To describe the technique for translaryngeal percutaneous arytenoid lateralization (TPAL) and the effect on rima glottidis cross-sectional area using a canine cadaveric model. Study design Ex vivo study. Animals Canine cadavers (n = 9). Materials and Methods With the aid of a laryngoscope, the larynx was visualized and a mattress suture (double-armed 2-0 polypropylene) was placed through the right arytenoid cartilage and exited the skin ventral to the jugular vein. The ends of the suture were passed through a button and tied on the skin to lateralize the right arytenoid cartilage. Digital images of the larynx were made before and after suture placement. Mean (±SD) rima glottidis cross-sectional area (mm2) was calculated from the digital images and values before and after suture placement were compared using a paired t-test. A P value < 0.05 was considered significant. Change in cross-sectional area was expressed as percent increase. Results Suture placement and the degree of arytenoid lateralization was relatively consistent in all dogs. Mean (±SD) cross-sectional area of the rima glottidis was 126.3 mm2 (±7.74) before and 172.1 mm2 (±24.7) after suture placement (P = 0.004). Mean percent increase in cross-sectional area was 25%. Conclusion The TPAL technique was effective at enlarging the rima glottidis in this canine cadaveric model. TPAL is rapid to perform and does not require specialized instrumentation. Results of this study support further investigation of the TPAL technique as an alternative to temporary tracheostomy for dogs in severe respiratory distress due to laryngeal paralysis.

A 10-year-old male neutered English bull terrier was referred for investigation of sneezing and stertorous breathing. Upper airway assessment under general anaesthesia was scheduled, along with a CT scan, bronchoscopy and bronchoalveolar lavage. The anaesthetic protocol consisted of acepromazine and butorphanol for premedication, propofol for induction, and isoflurane for maintenance of anaesthesia. Laryngoscopy during induction of anaesthesia revealed paradoxical collapse of both arytenoid cartilages with complete closure of the rima glottidis during inspiration. During bronchoscopy an electrocardiogram was attached which revealed atrial flutter. Atrial flutter was converted using lidocaine into a marked respiratory sinus arrhythmia. Six days later the dog was readmitted for unilateral cricoarytenoid lateralisation. No intraoperative or postoperative complications were encountered. It was speculated that atrial flutter was vagally mediated and occurred acutely during laryngoscopy. If atrial flutter is considered to be vagally mediated, lidocaine may serve as a useful treatment.

The aim of this study was to develop a minimally invasive thyroarytenoid lateralization technique (MITAL). Eleven unilateral MITAL procedures were performed on 11 canine cadavers. Two hypodermic needles were passed through the skin into the lumen of the larynx, penetrating the thyroid and arytenoid cartilages. Suture material was passed through the needles to lateralize the arytenoid cartilage. A rigid endoscope was used to visualize needle insertion and suture material placement. A key-hole approach to the larynx was performed and the suture material was knotted on the lateral aspect of the thyroid cartilage. The change in the rima glottidis area was recorded as were the duration of the procedure and complications encountered. The landmarks for needle insertion were easily palpated, and a significant increase in the area of the rima glottidis was documented after performing unilateral MITAL. In conclusion, unilateral MITAL is a quick, minimally invasive procedure which increases the area of the rima glottidis in cadaveric dogs.

In contrast to other athletic species such as people and greyhounds, which switch from nasal breathing at rest to oral breathing during exercise, the horse is an obligate nasal breather even during strenuous exercise. Dorsal displacement of the soft palate (DDSP) is a condition that occurs during exercise when the caudal border of the soft palate becomes displaced to a position above the epiglottis, resulting in obstruction of the rima glottidis during expiration. DDSP is considered to be the most common equine dynamic upper respiratory tract obstruction and is most prevalent in racehorses, but can also occur in sport and pleasure horses. This article gives an overview of DDSP and describes the more common treatments currently applied in the UK.

The objective of this experimental study was to evaluate the effects of cricoarytenoid (CA) joint preservation versus disarticulation on rima glottidis (RG) area with the epiglottis open and closed under both low and high suture tension. Canine cadaver larynges were used. A unilateral arytenoid lateralization (UAL) was performed with low or high suture tension and with the CA joint preserved or disarticulated. Rima glottidis area was measured with the epiglottis in an open and closed position. Results indicated that RG area was increased over baseline when UAL was performed with both low and high suture tension when the epiglottis was in an open position. High suture tension resulted in a greater increase in RG area compared to low suture tension, both when the CA was preserved and disarticulated. There was no difference in RG area when the CA was disarticulated versus preserved at either suture tension. Rima glottidis area was not significantly increased over baseline when the epiglottis was in a closed position except in the group with CA joint preservation and high suture tension. Although this study suggests that UAL can be performed with or without CA disarticulation, further studies are warranted before UAL without CA disarticulation can be recommended clinically.

Objective To determine the effect of a prototype dynamic laryngoplasty system (DLPS) on arytenoid abduction. Study design In vitro experimental. Study population Ten equine larynges. Methods Dissected larynges were mounted, and the right arytenoid was maximally abducted for testing. A left-sided laryngoplasty (LP) was performed by using a strand of No. 2 FiberWire and a FASTakII anchor. Phase 1 involved tightening the suture, without the DLPS device in place, in 1-mm increments and acquiring a digital image of the rima glottidis at each increment. Phase 2 involved tying the suture with the DLPS in place at a left to right quotient (LRQ) of 0.7. Digital images were subsequently taken at 3 stages of DLPS activation (0, 25, and 50 or maximal psi) and analysed to calculate LRQ. Results All tests were completed for 9 larynges. In phase 1, a total shortening of 25.89 ± 1.27 mm was possible, which increased the LRQ from 0.59 ± 0.02 to 1.07 ± 0.12. In phase 2, activation of the DLPS increased the LRQ from 0.70 ± 0.05 to 0.97 ± 0.09. This change in LRQ equated to 18.7 mm of shortening on the basis of phase 1 results. The maximum psi of the DLPS achieved was 37.33 ± 5.96. Conclusion The DLPS increased the degree of arytenoid abduction in vitro. This change in LRQ equated to 18.7 mm of shortening of the LP suture based on phase 1 results. Clinical impact These results support further evaluation of the DLPS to determine the effect of changes in DLPS on airway resistance.

Objective To evaluate variation in rima glottidis (RG) area and lack of epiglottic–glottic seal (LEGS) of the canine larynx associated with different suture anchor points in the arytenoid and cricoid cartilages, dissection of the cricoarytenoid joint capsule, section of the interarytenoid band, and disarticulation of the cricothyroid joint. Study Design Experimental study. Animals Cadaveric canine larynges (n = 18). Methods Larynges were assigned to 2 groups: group 1 = intact cricothyroid articulation and group 2 = cricothyroid articulation sharply sectioned. In each group, the arytenoid cartilage was lateralized successively as follows: (a) intact cricoarytenoid articulation, (b) cricoarytenoid articulation sharply sectioned, and (c) division of the interarytenoid band. Each variation was performed initially with the suture passed dorsally into the cricoid cartilage then with the suture passed laterally. Each time, the increase of rima glottis area (%) and the LEGS (mm2) were measured. Results Rima glottis area (RGA): when the suture was placed dorsally, division of the interarytenoid band resulted in a significant increase in RGA compared with groups with an intact band. Laryngeal distortion: when the suture through the cricoid cartilage was dorsal, LEGS increased with section of the cricothyroid articulation, dissection of cricoarytenoid articulation, and division of the interarytenoid band. Conclusion Unilateral arytenoid lateralization results in some degree of LEGS with a misalignment of the epiglottis over the RG. Our results revealed that the optimal RGA associated with the minimal LEGS was obtained with dorsal placement of a cricoarytenoid suture when the cricothyroid joint and the interarytenoid band were intact.

Summary Reasons for performing study To investigate laryngeal function in cases of recurrent laryngeal neuropathy pre- and post laryngoplasty (LP) using dynamic respiratory endoscopy (DRE). Objectives To compare the rima glottidis area during DRE pre- and post LP; document all forms of dynamic upper airway obstruction (DUAO) pre- and post LP and investigate the relationship between post operative abduction at rest and exercise. Study design Prospective case series. Methods Thoroughbred racehorses with pre- and post LP DRE were included. Left-to-right arytenoid cartilage angle ratios and rima glottidis area ratios were used to quantify laryngeal function during rest and exercise, pre- and post LP. Results In 35 horses, mean pre-LP ratios were greater during rest (left-to-right quotient angle ratio [LRQ] 0.76 ± 0.13; left-to-right arytenoid ratio [LRR] 0.72 ± 0.14; rima glottidis area ratio [RGA] 0.40 ± 0.10) than exercise (LRQ 0.39 ± 0.16, P

Unilateral cricoarytenoid laryngoplasty is commonly performed for treatment of idiopathic laryngeal paralysis in dogs. Determination of the appropriate tension applied to the suture can be difficult, particularly for the novice surgeon.To describe a technique for video-assisted unilateral cricoarytenoid laryngoplasty (VAUCAL) and to report short-term outcome in dogs undergoing VAUCAL.Dogs (n = 14) with bilateral idiopathic laryngeal paralysis undergoing VAUCAL between August 2011 and May 2013 were evaluated. A cricoarytenoid suture was tensioned under video observation of the rima glottidis using a 5-mm rigid endoscope. Real-time visualization of arytenoid abduction during suture tensioning, and final arytenoid position were assessed. Requirement for additional intravenous anesthestic, intra- and post-operative complications and short-term outcomes were documented.Adequate, real-time visualization of the larynx during tensioning of the cricoarytenoid suture was accomplished in 13/14 dogs. Additional intravenous anesthesia was required in 5/14 dogs to facilitate reintubation. Final arytenoid position was considered inadequate in two dogs on post-operative trans-oral laryngeal examination. Recurrence of clinical signs occurred in one dog three months following initial surgery. Owner outcome was deemed good (n = 8) or excellent (n = 6).VAUCAL is a feasible technique to permit direct real-time visualization of the larynx during tensioning of the cricoarytenoid suture, and enables assessment of final arytenoid position intra-operatively by the operating surgeon.VAUCAL allows the operating surgeon to assess arytenoid abduction intra-operatively, at the time of knot placement. This technique may be particularly useful for the novice surgeon or surgeon in training.

OBJECTIVE: To determine the effect of horse age and laryngeal prosthesis location on rima glottidis area in cadaveric larynges. STUDY DESIGN: Experimental study. ANIMALS: Cadaveric equine larynges (n = 40). METHODS: Specimens were grouped by age: group 1, ≤5 years (n = 18); group 2, >5 to ≤10 years (n = 12); group 3, >10 years (n = 10). A cranial prosthesis was placed through the dorsal cricoid spine at 70% of the distance of the total cricoid length measured from the caudal rim. A dorsal prosthesis was placed through the caudal rim of the cricoid on the dorsal midline. A lateral prosthesis was placed 1.5 cm lateral to the dorsal prosthesis. All prostheses passed through the muscular process. Rima glottidis area was determined after progressively tightening each suture in 5 N increments from 0 N to 35 N using a tensiometer. RESULTS: There was no significant effect of age on the area of the rima glottidis at any load for any of the three prosthesis locations. CONCLUSIONS: Age did not affect the area of the rima glottidis when prostheses were loaded between 5 N and 35 N.

Objectives: To evaluate the effect of 3 laryngeal prostheses alone or in combination on rima glottidis area in horses. Study Design: Experimental randomized design. Sample Population: Cadaveric equine larynges (n=22). Methods: Three prostheses were preplaced in each of 14 larynges. Rima glottidis area was measured after loading each suture in 5Newton (N) increments from 0N to 35N. In 8 larynges, the 3 prostheses were tied alone or in combination at a fixed load of 15N and rima glottidis area measured. Results: Rima glottidis cross-sectional area increased as the load on each prosthesis increased with maximum area reached at 20N for each prosthesis. At a fixed load of 15N, tying 2 and 3 prostheses in combination resulted in a larger rima glottidis cross-sectional area than achieved with each prosthesis alone. Conclusions: A combination of 2 or 3 prostheses tied at a fixed load of 15N optimized rima glottidis cross-sectional area irrespective of the anatomic location of the prosthesis.

SummaryReason for performing study Two forms of dynamic upper respiratory tract obstruction affecting racehorses that involve the soft palate have been described: palatal instability (PI) and dorsal displacement of the soft palate (DDSP). Observation of DDSP is straightforward in that it is an all or nothing event, whereas observation of PI is subjective and interpretation may vary between clinicians. Objectives The aim of this study was to attempt to characterise PI and to investigate endoscopic features that precede DDSP. Methods A retrospective study on the endoscopic observations of Thoroughbred racehorses referred for high-speed treadmill endoscopy was performed. Endoscopic observations were reviewed during the last 10 s of the exercise test or the last 10 s prior to DDSP. The degree of axial deviation of the aryepiglottic folds (ADAF), the conformation of the epiglottis, the conformation of the soft palate and the amount of obstruction of the rima glottidis by the soft palate (i.e. soft palate stability) were assessed. Results A total of 72 horses were included in this study, of which 7 showed no evidence of PI. Of the 65 horses with PI, 30 (46%) developed DDSP. There were significant associations between the stability of the soft palate, epiglottic conformation and ADAF. Furthermore, development of DDSP was associated with increased severity of PI and ADAF and with changes in epiglottic conformation. Conclusions This study has characterised the endoscopic features associated with PI and identified certain characteristics that precede DDSP. Potential relevance These observations may assist veterinary surgeons in recognising PI and the prodromal signs of DDSP.

Laryngeal hemiplegia is a naturally occurring disease of a horse recognized as a common reason of the poor performance. This syndrome is diagnosed by a human through an endoscopic observation. The asymmetry of arytenoid cartilages is calculated by left to right angle quotients (LRQ). However, human inspection may misdiagnose the disease. Therefore, an automatic diagnostic system is expected to analysis the asymmetric view of laryngeal hemiplegia. In this paper, we have proposed an automatic way to analysis laryngeal hemiplegia by combining image segmentation and parabola fitting algorithms. Our method includes six steps: (1) hierarchical contour map is achieved by a state-of-the-art hierarchical image segmentation method joining Global Probability of Boundary (gPb), Oriented Watershed Transform (OWT), and Ultrametric Contour Map (UCM); (2) key curves are extracted; (3) boundaries are confirmed by Parabola fitting method; (4) dorsal-most point of rima glottidis is selected; (5) proximal-most point is identified and (6) LRQ is calculated as the final measurement. To evaluate the accuracy of our proposed method, a dataset of horse larynx endoscopic images has been built up and tested. Experimental results have shown that the proposed method has good performance. 

Summary This case report describes the endoscopic findings and outcome in 6 horses diagnosed with dynamic epiglottic retroversion (ER) during exercise. Horses included 2 showjumpers, one eventer, one pleasure riding horse and 2 Thoroughbred racehorses. All were adults (age range: 4–10 years). Dorsal angulation of the epiglottis was identified at rest in one horse. However, resting endoscopy was unremarkable in the remaining 5 horses. Exercising endoscopy was performed during high-speed treadmill exercise in 3 horses and during ridden exercise in the other 3. Intermittent ER occurred during inspiration in all horses and the frequency increased with increasing speed. In 2 horses the epiglottis retroverted beyond the rima glottidis. All horses made an abnormal respiratory noise described as a ‘grunt’ when retroversion of the epiglottis occurred. Poll flexion was found to be an exacerbating factor in the nonracehorses. Two horses continued in work but abnormal inspiratory noise persisted. Surgical treatment, in the form of subepiglottic resection, was attempted in one horse. However, it never raced again after the procedure. Of the remaining horses, 2 were retired and the third was subjected to euthanasia.

Objectives To objectively measure and subjectively score the effect of 3 anesthetic induction protocols on arytenoid cartilage motion in normal cats. Study Design Randomized prospective clinical study. Animals Cats (n = 35) without previous history of respiratory dysfunction. Methods Cats were randomly assigned to administration of alfaxalone, propofol, or midazolam and ketamine to induce anesthesia after premedication with methadone. Videolaryngoscopy was performed. Still images at maximum inspiration and expiration were used to measure the area and height of the rima glottidis. Change in rima glottidis area and of normalized glottal gap area (NGGA = area/height2) was calculated. Subjective scores for arytenoid movement were obtained. Kruskal–Wallis test was performed on change of NGGA and rima glottidis area. Results No statistically significant difference was found between groups for age, sex, body weight, and body condition score. Percentage increase of rima glottidis area and change in NGGA were similar for all groups (P = .33 and P = .29). No significant differences were found for subjective scores between groups (P = .54). Arytenoid movement was not detected during videolaryngoscopy and subjective scoring in 3 cats anesthetized with propofol and in 3 cats anesthetized with midazolam and ketamine, despite presence of respiratory movements. Conclusions No difference in laryngeal motion was observed between the 3 protocols used to induce anesthesia in cats premedicated with methadone.

Objective—To evaluate effects of the arytenoid lateralization technique and suture tension on airway pressure in the canine larynx. Sample—7 canine cadaver larynges. Procedures—Negative pressure was elicited aboral to the larynx. Airway pressure was measured at airflows of 15 to 120 L/min before and after thyroarytenoid lateralization (TAL), cricoarytenoid lateralization (CAL), and combined TAL and CAL (cricothyroarytenoid lateralization [CTAL]) at 100 and 500 g of suture tension and with sectioning of the sesamoid cartilage (SSC) and disarticulation of the cricothyroid joint (DCTJ). Rima glottidis area (RGA) was measured. Effects of technique, modification, and suture tension on pressure and RGA were evaluated statistically. Results—Increased suture tension significantly reduced airway pressure for TAL at 30 L/min, CAL at 45 to 120 L/min, and CAL after SSC and DCTJ at 60, 75, and 105 to 120 L/min. The CAL and CTAL caused significantly lower airway pressures than did TAL > 30 L/min, but SSC and DCTJ did not significantly reduce pressure. All procedures, except TAL at 100 g of tension, resulted in a significant RGA increase from baseline. The CAL and CTAL caused a significantly greater RGA than did TAL. For TAL at 100 g of tension, SSC significantly increased RGA. Conclusions and Clinical Relevance—CAL and CTAL caused lower airway pressures than did TAL. No significant pressure differences were detected between CAL and CTAL; SSC and DCTJ had little effect on pressure. Pressure may be a more sensitive indicator of airflow than is RGA in the larynx of canine cadavers.

Objective: To determine whether ventriculocordectomy (VCE) performed before prosthetic laryngoplasty (PL) results in increased rima glottidis size compared with PL alone. Study Design: Experimental study. Animals: Equine cadaver larynges (n=13). Methods: Right arytenoid cartilages were maximally abducted using a standard PL technique. Standard PLs were then performed on the left side and the force required to maximally abduct the left arytenoid cartilage recorded (Fmax). Photographs were taken of the rima glottidis at zero force and at five equal levels of force up to Fmax. The force applied was released, left VCE performed, and photographs repeated. Arytenoid left:right angle quotients (LRQ) and glottic cross-sectional area ratios (CSAR) were calculated at each force level in each condition (PL and VCE-PL). Results: Mean LRQ and CSAR for both PL and VCE-PL increased with increasing force, initially rapidly before plateauing at ∼50% of Fmax. LRQ and CSAR were significantly greater for VCE-PL than for PL (P

Objective: To evaluate the effect of Nitinol stents for bilateral arytenoid lateralization on canine laryngeal resistance. Study Design: Ex vivo experimental study. Animals: Canine cadaver larynges (n=7). Methods: Laryngeal resistance was calculated in all specimens with the epiglottis in open and closed positions. Bilateral arytenoid stenting was performed, rima glottidis width measured, and laryngeal resistance calculated. The effects of stenting on laryngeal resistance were evaluated by repeated measures ANOVA. Results: Calculated laryngeal resistance in the 3 stented groups, 2 cm (0.034±0.059 cmH2O/L/s), 3 cm (0.034±0.059 cmH2O/L/s), and 4 cm (0.034±0.059 cm H2O/L/s), was significantly decreased versus the control (unstented) group (0.947±0.624 cmH2O/L/s; P=.0098) with an epiglottis in the normal position. Calculated laryngeal resistance in the 3 stented groups, 2 cm (43.407±17.348 cm H2O/L/s), 3 cm (70.659±34.705 cmH2O/L/s), and 4 cm (92.637±44.509 cm H2O/L/s), was significantly increased versus the control (unstented) group (29.561±14.499 cm H2O/L/s) (P=.0185) with an epiglottis in the closed position. The width of the rima glottidis correlated with the size of the stent (r=0.95, P

Case Description—A 5-month-old neutered male Golden Retriever was evaluated because of moderate stridor, exercise intolerance, and dyspnea. The dog had been neutered 3 weeks previously, and the referring veterinarian identified a large fluid-filled swelling on the left lateral aspect of the larynx during anesthetic intubation for that surgery. The referring veterinarian drained fluid from the mass by use of needle centesis via the oral cavity, which resulted in temporary improvement in clinical signs; however, the clinical signs returned soon thereafter. Clinical Findings—A large, soft, spherical mass was located between the left arytenoid and thyroid cartilages and axial to the left ceratohyoid bone, thus causing partial obstruction of the rima glottidis. Laryngoscopic examination, computed tomography (CT), and cytologic evaluation of aspirates performed before surgery; examination during surgery; and histologic evaluation of tissues following surgical excision confirmed the diagnosis of a laryngeal cyst. Treatment and Outcome—Complete surgical excision was successfully performed via a lateral extraluminal approach to the larynx. One week after surgery, the dog coughed only occasionally. Twelve months after surgery, the owner reported that the dog was clinically normal with no recurrence of clinical signs, and laryngoscopic examination revealed no recurrence of the cyst or other pathological changes in the laryngeal region. Clinical Relevance—Congenital laryngeal cysts are rarely reported in domestic animals. The information provided here described the CT appearance of a laryngeal cyst and the use of CT in diagnosis and surgical planning. Congenital laryngeal cysts can be resected via a lateral submucosal approach.

Vocal alterations after thyroidectomy are generally related to laryngeal nerve injury or laryngotracheal mobility disorders caused by postoperative fibrosis or strap muscle lesion. AIM: this study aims to evaluate the frequency of vocal and rima glottidis disorders after thyroidectomy. MATERIALS AND METHOD: This is a prospective study based on 35 patients submitted to thyroidectomy under local anesthesia and hypnosedation. All patients underwent voice auditory perception evaluation, voice acoustic tests and videolaryngostroboscopy preoperatively, and at one week and at 30 days postoperatively. Bilateral cricothyroid muscle electromyography was performed on the thirtieth day after surgery to confirm the presence of injury in the external branch of the superior laryngeal nerve. RESULTS: 14.3% of the patients presented posterior glottis deviation before surgery and normal electromyography findings. Transient and permanent vocal alteration occurred in 25.7% and 14.2% of the patients respectively. CONCLUSION: voice disorders evaluated after voice auditory perceptive evaluation and voice acoustic tests were more intense in the group with superior laryngeal nerve external branch injury than in the injury-free dysphonic patient group. Oblique glottis can be present in normal patients; however its onset after thyroidectomy is indicative of superior laryngeal nerve external branch lesion.

Objective— To describe the signalment, history, clinical signs, surgical technique, and outcome for cats with laryngeal paralysis that had arytenoid lateralization. Study Design— Case series. Animals— Cats with laryngeal paralysis (n=10). Methods— Medical records (1996–2002) for cats with laryngeal paralysis that had arytenoid lateralization were reviewed for signalment, history, clinical signs, degree of paralysis, cause, concurrent medical conditions, surgical technique, and outcome. Follow-up information was obtained from owners or referring veterinarians. Results— Of 10 cats, 9 had bilateral and 1 had unilateral laryngeal paralysis. Arytenoid lateralization were unilateral (n=7), bilateral (1), and staged bilateral procedures (2), 10 days and 3 years apart, respectively. Postoperatively, 1 cat had persistent inspiratory noise because of minimal enlargement of the rima glottidis and 2 cats required a temporary tracheostomy for management of laryngeal swelling. Three cats developed aspiration pneumonia and died 4, 7, and 150 days after surgery; all 3 had bilateral (simultaneous or staged) procedures. Of the 7 remaining cats, 4 were alive at follow-up and 3 had died of causes unrelated to arytenoid lateralization. The calculated mean survival time for all 10 cats was 406 days (median, 150 days; range, 4–1825 days). Conclusions— Arytenoid lateralization was effective at enlarging the rima glottidis and reducing signs of airway obstruction in most cats. Clinical Relevance— Unilateral arytenoid lateralization is a feasible option for the surgical management of cats with marked clinical signs; however, bilateral procedures should be avoided or at least performed with considerable caution because of the apparent risk for aspiration pneumonia.

Parkinson's disease (PD) is a progressive, incurable neuro-degenerative disease. Symptoms appear when approximately 70% of mid-brain dopaminergic neurons have died. Temporal analysis of the calculated area of the rima glottidis may give an indication of vocal impairment. In this paper, we present an automatic segmentation algorithm to segment the rima glottidis from 4D CT images using texture features and support vector machines (SVM). Automatic two dimensional region growing is then applied as a post processing step to segment the area accurately. The proposed segmentation algorithm resulted in accurate segmentation and we demonstrate a high correlation between the manually segmented area and automatic segmentation.

Introduction Laryngeal paralysis is a condition in which failure of arytaenoid abduction results in a reduced rima glottidis cross-sectional area. The most commonly performed surgical techniques rely on unilateral abduction of the arytaenoid, requiring a lateral or ventral surgical approach to the larynx. Aims and objectives The aim of the study was to investigate a novel minimally invasive intralaryngeal thyroarytaenoid lateralisation technique, using the Fast-Fix 360 meniscal repair system. Materials and methods Larynges were harvested from large breed canine cadavers. With the aid of Kirschner wires placed between the centre of the vocal process and the centre of an imaginary line between the cranial thyroid fissure and the cricothyroid articulation, the mean insertion angle was calculated. Results The Fast-Fix 360 delivery needle inserted intralaryngeally (n=10), according to a simplified insertion angle (70°), resulted in thyroid penetration (>2.5 mm from margin) in all patients. The Fast-Fix was applied unilaterally at 70° with the first toggle fired on the lateral aspect of the thyroid cartilage and inside the laryngeal cavity on retraction. The suture was tightened. Preprocedural (61.06±9.21 mm2) and postprocedural (138.37±26.12 mm2) rima glottidis cross-sectional area was significantly different (P

OBJECTIVE To evaluate whether the ultrashort-acting neuromuscular blocking agent gantacurium can be used to blunt evoked laryngospasm in anesthetized cats and to determine the duration of apnea without hemoglobin desaturation. ANIMALS 8 healthy adult domestic shorthair cats. PROCEDURES Each cat was anesthetized with dexmedetomidine and propofol, instrumented with a laryngeal mask, and allowed to breathe spontaneously (fraction of inspired oxygen, 1.0). The larynx was stimulated by spraying sterile water (0.3 mL) at the rima glottidis; a fiberscope placed in the laryngeal mask airway was used to detect evoked laryngospasm. Laryngeal stimulation was performed at baseline; after IV administration of gantacurium at doses of 0.1, 0.3, and 0.5 mg/kg; and after the effects of the last dose of gantacurium had terminated. Duration of apnea and hemoglobin oxygen saturation (measured by means of pulse oximetry) after each laryngeal stimulation were recorded. Neuromuscular block was monitored throughout the experiment by means of acceleromyography on a pelvic limb. RESULTS Laryngospasm was elicited in all cats at baseline, after administration of 0.1mg of gantacurium/kg, and after the effects of the last dose of gantacurium had terminated. The 0.3 and 0.5 mg/kg doses of gantacurium abolished laryngospasm in 3 and 8 cats, respectively, and induced complete neuromuscular block measured at the pelvic limb; the mean ± SE duration of apnea was 2 ± 1 minutes and 3 ± 1.5 minutes, respectively. Hemoglobin oxygen saturation did not decrease significantly after administration of any dose of gantacurium. CONCLUSIONS AND CLINICAL RELEVANCE Gantacurium may reduce tracheal intubation-associated morbidity in cats breathing oxygen.

Objectives To compare the effects of IV doxapram on glottic size and arytenoid motion in normal dogs and in dogs with laryngeal paralysis. Study design Prospective experimental and clinical trials. Animals Six healthy dogs weighing 24.5 ± 3.9 kg and six dogs weighing 27.4 ± 11.5 kg suspected of having laryngeal paralysis. Methods Dogs were pre-medicated with acepromazine and butorphanol, and a light plane of anesthesia was induced with isoflurane by mask. Videoendoscopic examination of laryngeal function was recorded before (baseline) and after IV doxapram administration. Normalized glottal gap area (NGGA) at maximal inspiration and expiration, and percentage change in height, width, area, and NGGA were calculated with measurements from digitized images of the glottal gap. Results Active arytenoid motion was present in all normal dogs at baseline. After doxapram administration, depth of respiration appeared greater, but arytenoid motion, as measured by percentage change in NGGA, and in area and width, did not significantly increase in normal dogs. No arytenoid motion was detected in dogs with laryngeal paralysis at baseline; however, rima glottidis NGGA of dogs with laryngeal paralysis was greater at inspiration and expiration than normal dogs. After doxapram administration, dogs with laryngeal paralysis developed paradoxical arytenoid motion and significant, negative percentage change in area (−61%) and NGGA (−145%) because of inward collapse of the arytenoids during inspiration. Conclusions and clinical relevance Administration of doxapram during laryngeal examination is useful for differentiating normal dogs from dogs with laryngeal paralysis. Dogs with laryngeal paralysis may suffer extreme glottic constriction with vigorous respirations, and may require intubation during examination.

BACKGROUND: Since the beginning of the Christian era, numerous reports have dealt with the construction and functional organization of the larynx, thus stressing its role as the keystone of vocalization in vertebrates. The purpose of this review is to provide a comprehensive summary of basic anatomical facts and to point out certain new aspects of the innervation of laryngeal muscles. METHODS: The data presented herein were collected from a preliminary gross anatomical study performed in six human individuals at our institute, and from published literature. RESULTS: The basic framework of the human larynx is composed of the hyaline thyroid, cricoid and arytenoid cartilages, the fibroelastic epiglottis and the hyoid bone. Two pairs of synovial articulations, i.e. the cricothyroid and cricoarytenoid joints, provide the mobility needed to adjust the tension of the vocal ligaments. The intrinsic laryngeal muscles may be divided into three functional groups: (i) muscles varying the rima glottidis (the transverse arytenoid as well as the lateral and posterior cricoarytenoid muscles); (ii) muscles regulating tension in the vocal ligaments (i.e. the cricothyroid, posterior cricoarytenoid as well as the compound thyroarytenoid and vocalis muscles) and (iii) muscles modifying the laryngeal inlet (the so-called ‘sphincter aditus’, which is formed by the oblique arytenoid and aryepiglottic muscles and counteracted by the thyroepiglottic muscle). They are innervated by the superior and inferior laryngeal nerves branching off the vagus nerve. The external branch of the superior laryngeal nerve exclusively supplies the cricothyroid muscle. There is strong evidence that the lateral cricoarytenoid and the thyroarytenoid muscles are solely supplied by the inferior laryngeal nerve. All other intrinsic laryngeal muscles seem to receive motor fibres either from both laryngeal nerves or from the internal branch of the superior laryngeal nerve alone. CONCLUSIONS: Thus, the traditional concept of motor innervation of the larynx seems to be out of date. In fact, the internal branch of the superior laryngeal nerve should no longer be seen as purely sensory but rather – as also the inferior laryngeal nerve – as a mixed nerve containing sensory as well as motor fibres.

Objectives— To evaluate the clinical outcome and percentage increase in rima glottidis area achieved using a combined technique of cricoarytenoid and thyroarytenoid cartilage lateralization compared with cricoarytenoid cartilage lateralization alone in live anesthetized dogs clinically affected with bilateral laryngeal paralysis. Study Design— Randomized prospective clinical study. Animals— Twenty dogs with bilateral laryngeal paralysis. Methods— Bilateral laryngeal paralysis was diagnosed by direct laryngoscopy. Each dog was allocated randomly to 1 of 2 surgical groups: CAL (cricoarytenoid lateralization) and CTAL (cricoarytenoid and thyroarytenoid lateralization). Photographs were taken of each larynx before and after surgery, the images were digitized, and the preoperative and postoperative areas of each rima glottidis were measured. The percentage increase in rima glottidis area produced by each of the arytenoid lateralization procedures was compared. Follow-up was obtained by telephone survey of owners and referring veterinarians. Results— There was no significant difference in mean (± SD) percentage increase in rima glottidis area for the CAL group (241.5 ± 42.9%) or the CTAL group (236.4 ± 44.5%). Clinical follow-up (median, 18 months postoperatively) indicated 60% of the dogs were still alive and only 1 dog had died as a result of complications related to surgery. Conclusions— CTAL for the treatment of canine laryngeal paralysis does not significantly increase rima glottidis area compared with CAL alone. The mean percentage increase in rima glottidis area obtained with both procedures was comparable to previously reported mean increases with CAL in live anesthetized dogs. Both procedures resulted in good long-term clinical outcome. Clinical Relevance— CTAL is as effective as CAL in providing an increased rima glottidis for the treatment of bilateral laryngeal paralysis in dogs.

Objectives— To evaluate the effect of abduction suture tension and cricothyroid (CT) joint disarticulation on the area, height, and width of the rima glottidis (RG) during unilateral arytenoid lateralization. Study Design— Experimental study. Animals— Nine canine cadaver larynges. Methods— Left arytenoid lateralization was performed with high or low abduction suture tension. RG area, height, and width were measured by computerized planimetric analysis with the epiglottis in an open and closed position. The experiment was performed with the CT joint intact and disarticulated. The effects of suture tension, CT disarticulation, and their interaction on RG area with the epiglottis closed or open were evaluated by repeated measures analysis of variance (ANOVA). Results— RG area increased by 82% and 129% (P < .0001) with low and high suture tension, respectively. The aperture not covered by the epiglottis in a closed position was 467% larger with high suture tension than with low tension (P < .0001). CT disarticulation had no significant effect on RG geometry with either low or high suture tension (P= .4970). Conclusions— Low suture tension increased RG area when the epiglottis was in an open position without increasing RG aperture when the epiglottis was closed. Suture tension had a significant effect on RG opening when the epiglottis was closed. CT disarticulation did not modify the geometry of the RG. Clinical Relevance— Use of a low-suture tension should be considered during arytenoid lateralization because it has the potential to reduce the risk of aspiration pneumonia.

In horses with laryngeal hemiparesis/hemiplegia, the degree of deficit of the abductor branches of the left recurrent laryngeal nerve causes varying degrees of decrease of both vocal cord and arytenoid cartilage movement. During inhalation, the vocal cord of affected horses is displaced axially, increasing impedance, decreasing ventilation, and causing an upper-respiratory noise. Clinically incomplete or absent abduction of the left arytenoid cartilage and vocal cord is manifested by impaired performance and/or upper-respiratory noise. Many treatments have been used for preventing these paradoxical movements, increasing the diameter of the rima glottidis, and reducing the noise produced during exercise. This article describes the vocal cordectomy technique that is performed to reduce the exercise intolerance in horses working a low velocity (draft horses) and in all horses to reduce the abnormal sound created with laryngeal hemiplegia. Vocal cordectomy is also performed by many surgeons as an adjunct to the laryngoplasty procedure. Vocal cordectomy is felt to increase the ventral diameter of the rima glottidis, reduce the noise associated with laryngeal hemiparesis/hemiplegia, and if the laryngoplasty loses some abduction, prolong the results by increasing the ventral diameter of the larynx. When performed with either the diode or the Nd:YAG laser as described in this article, the vocal cordectomy is performed as a standing procedure. This has the advantage of being well tolerated by the horse, and does not require general anesthesia or a laryngotomy. When performed as an adjunct to the laryngoplasty, standing laser vocal cordectomy decreases the general anesthesia time and eliminates the need to change the patient position.

Laryngeal collapse is a progressive condition characterised by a loss of cartilage rigidity which allows medial deviation of the rostral laryngeal cartilages (Pink and others 2006, Torrez and Hunt 2006, White 2012). The condition is usually considered to be secondary to chronic upper airway obstruction, most commonly in brachycephalic airway syndrome (BAS) due to the excessive intraluminal pressure changes during the respiratory cycle. These pressure changes lead to cartilage fatigue, and repetitive cartilage deformation results in obstruction of the rima glottidis (Pink and others 2006). Direct trauma may also disrupt the laryngeal cartilages thereby allowing medial collapse (Fossum 2013). The breeds most commonly affected by BAS include the English and French bulldog, Boston terrier, pug, pekingese, shih tzu and boxer (Poncet and others 2006, Torrez and Hunt 2006, Riecks and others 2007, De Lorenzi and others 2009, Mercurio 2011, Johnson and others 2013). The primary features of BAS occur as a result of the rostrally shortened skull exhibited by these breeds (Pink and ­others 2006, Fasanella and others 2010). The compressed nasal passage is associated with a relatively elongated and thickened soft palate, abnormal nasal turbinates and distortion of the pharyngeal soft tissues. Primary features also include stenotic nares and a hypoplastic trachea (Pink and others 2006, Torrez and Hunt 2006, Riecks and others 2007, De Lorenzi and others 2009, Fasanella and others 2010). Affected animals may possess one or more of these abnormalities which all contribute to …

A six-year-old male neutered Yorkshire terrier was evaluated for severe, acute-onset, inspiratory dyspnoea. Laryngoscopy revealed retroversion of the epiglottis with intermittent occlusion of the rima glottidis during inspiration. The dog underwent both temporary and permanent epiglottopexy procedures that were unsuccessful. Subtotal epiglottectomy was performed and resulted in permanent resolution of dyspnoea without evidence of dysphagia or aspiration. This case highlights potential complications associated with management of this condition as well as describing the successful use of subtotal epiglottectomy in the dog.