Vet Reports

LARGEAL PARALYSIS (CANINES)

Use of silicone materials (Stening®) for the correction of this pathology. Advantages and disadvantages with respect to other materials used and other surgical resolution techniques.
Dr. MV Carina Passeri(1); MV Rafael B’kenhans(1); MV Yesica DiBenedetto(1); MV Pablo Hall(2); MV Esteban Caparrós(1) Contact: ecaparros@fvet.uba.ar
(1) Respiratory disease service in small animals FCV UBA
(2) Surgery service in small animals FCV UBA

1.- INTRODUCTION: when talking about laryngeal paralysis is encompassing a combination of possible pathologies, to explain that there is a condition of closure or opening of the larynx. It can be of acquired or congenital cause. Congenital forms are rare, among patients with congenital alterations are the Bouvier of Flanders, Siberian Huskies and Bull and American Stafford Terrier. In Buenos Aires, Argentina, it is the Labradors or the Golden Retrievers who have the greatest tendency to have paralysis or laryngeal hemiplegia. Regardless of whether they are male or female. Usually large breeds of size and age. The predominant clinical sign is the laryngeal stridor in inspiration, well audible without the need for a phonendoscope. Other clinical signs include dysphonia or loss of phonation, exercise intolerance. It may be associated with syncopes, drownings, heatstrokes. Its appearance can occur at any time of the year and can reach the consultation as a real urgency, however when stabilized it can be treated very well in medical and environmental management form, until it is taken to surgery. For surgical resolution, various techniques have been developed, more or less invasive, until the appearance of silicone stents (Stening ®) that easily solved a large problem, with fewer complications. Then the airway specialist or the derived clinician will find the cause of largeal paralysis.

 

2.- MATERIALS AND METHODS: at the School Hospital of the Faculty of Veterinary Sciences of the U.B.A. were attended in the current year 2019, 13 patients with suspected laryngeal paralysis, 9 of them were subjected to the placement of human tracheal stent adapted to canines, according to the size of animals ranging from yorkshire terrier, co spanckeriel , medium half-breeds up to labradors and golden retrievers.
All those diagnosed, through direct observation under anesthesia, by laryngoscopy performed by the FCVUBA respiratory disease service*, were referred to the surgical office for evaluation for laryngeal stent placement.
These patients were intervened by Dr. Pablo Hall and were placed with this prosthesis. Stening ® brand silicone materials were acquired by the owners in that entity at a special price for the patients of the faculty, it is worth highlighting the great economic difference between them with prices to the non-hospital public, which has contributed to being able to carry out these practices without having to rely purely on the economic.
In this work, the issue of patient stabilization in urgency will not be taken into account, sedation, body temperature control, the use of anti-inflammatory drugs, oxygen (with or without endotracheal intubation) will be addressed, perhaps on another occasion.

2-a.- TRADITIONAL SURGICAL TECHNICALS:

TRAQUEOSTOMIA: it is always a good resource in the emergency, before a patient who does not become stabilized and who is at risk of life by
suffocation or drowning.
• ADVANTAGES: the immediate resolution of the laryngeal problem, by avoiding the passage of air through the larynx, also contributes to that area so punished by turbulence and inflammation, improve over time, when not used returns to its normal state by disuse and allows the patient a very good ventilation and gas exchange.
• DISADVANTAGES: not well tolerated by responsible forks, its management becomes difficult(2) to be obstructed with thick tracheal secretions, a patient presented an infectious picture on the trachea at stoma level, which he referred with antibiotics and in no case were associated pneumonia observed. This dog underwent surgery and now carries a permanent tracheostomy tube to relieve his breathing problems.

CORDECTOMY: the excision of ventral vocal folds, often accompanied by another surgical correction.
• ADVANTAGES: it is a simple technique when approached from the oral cavity
• DISADVANTAGES: the area may be edematized and temporary tracheostomy may be needed. Excessive healing can lead to a major complication so the opening or tracheostomy should be corrected.

LARINGECTOMY PARCIAL: is a combination of techniques where vocal folds and aritenoids are split leaving cuneiform processes intact.
• ADVANTAGES: from oral cavity it becomes easier.
• DISADVANTAGES: 50% of patients have complications, cough, carraspera, bleeding, edema, pneumoa aspiration with consequences of subsequent pneumonic processes and the tracheostomy is sometimes reached.

LATERALIZATION OF ARITENOIDES CARTILAGE: the approach is from the side of the neck, it is a complex technique consisting of several steps, to finally fix the aritenoid cartilage.
• ADVANTAGES: Although invasive, it is a resolution that tries to maintain the normal physiology of the larynx, it is the one that brings the least amount of complications.
• DISADVANTAGES: in patients who fail the technique, the usual signs of pneumoa aspiration occur.

2-b.- INNOVATIVE SURGICAL TECHNICALS:

LARYNGEAL DILATATOR PLACEMENT (STENT): a synthetic, silicone, tubular material is placed that maintains the physiological opening of the glotidis rhyme and is fixed with dots.
• ADVANTAGES: simple and fast technique, practically without complications.
• DISADVANTAGES: the cost of the material to the public.

3.- COMPARISON OF STENT (STENING®) WITH OTHER SURGICAL TECHNIQUES.

3-a.- THE MATERIAL: a Stening ® brand silicone tube is used, with great resistance to physical pressures, and natural fluids, saliva, digestive reflux. In human medicine, these products can reach, unchanged, up to 10 years, placed in tracheal light, which generates a high expectation, since average patients with paralysis or laryngeal hemiplegia are around 8 to 12 years of age. This material does not react with the laryngeal mucosa, so it allows the durability of its use.

3-b.- DIMENSIONS: the tracheal Stent (Stening ®) for use in human medicine will be adapted to the larynx of each particular patient, although most patients treated by this method are of large size, in cases that were required smaller stent, they could be available. The diameter is similar in almost all cases, ranging from 14 mm to 17.5 mm and the length from 30 mm to 80 mm. It is the authors’ preference to range from 14 to 15 mm in diameter and 30 to 60 mm long.

3-c.- PLACEMENT: being of oral approach, it is much simpler than other techniques, you should have a firm device that keeps the patient attached behind the upper canines, suspended in the air so that it keeps the mouth open and does notcomfortable the activity of the surgeon. The patient should therefore be placed in a stenal decubbital position. The necessary field cloths shall be placed and a good source of light shall be available in the field of work. Compared to other oral approach techniques, cordectomy, partial laryngectomy, there would be no differences with the laryngeal dilator placement technique, there are differences with approaches from the side of the neck where the patient is placed in lateral decubbital and the area is prepared with tritomy and surgical lavages. The placement itself is done with a clamp of Kocher or one of Allis, the tube folds taking it from the outer edges, being flattened and inserting it into the larynx through the rhyme glotidis. The branches of the clamp used are opened, a left hand clip can be used to hold the prosthesis. It settles by exceling just in front of aritenoid cartilage. Then you proceed to fix it with points. Placing the stitches may cause bleeding in nappa that disappears quickly. In the other techniques mentioned, bleeding and inflammation should be monitored. In the placement of dilators this is practically non-existent.

3-d.- COMPLICATIONS: practically no complications are recognized in the placement of largeal dilators, at the dawn of the application of this technique, it can be clarified that it is not its own, errors occurred for not fixing the stent with points, by contamination of the material, migration of it through the respiratory tract, by inadequate size of the same. But since some details were adjusted, the material, the diameter and length, there were virtually no complications. An Akita Inu patient, presented an inflammatory reaction, a new stent was placed and at 4 weeks he repeated the picture, was the only patient with this type of manifestation. In the immediate post-surgical period, clinical signs of carrasping and unproductive arching were observed, but in all cases the stridor and inspiring effort disappeared completely. In traditional techniques bleeding, edema was observed, so it was needed to make a tracheostomy in principle temporary. Some patients showed signs of pneumoa aspiration, in patients treated with Stening silicone materials, no lower airway complications were observed. In the placement area of points after 48 hours, no edema or bleeding was observed. Over time, no alteration in healing was observed as in other techniques. No maintenance or cleaning is required with stents once placed.

4.- CONCLUSIONES: con la introducción de los stents de silicona (Stening ®) se ha dado un gran paso en la resolución de los signos clínicos que aparecen con las enfermedades laríngeas, desapareciendo el estridor y el esfuerzo inspiratorio. Brindando calidad de vida a nuestros pacientes, evitando el ahogo y el golpe de calor, que se genera como consecuencia de la inspiración forzada. Esta técnica proporciona menor cantidad de complicaciones, prácticamente la lleva a cero y es muy factible de realizar.

5.- BIBLIOGRAFÍA:
1.Vandenberghe H1, Escriou C2, Rosati M3, Porcarelli L4, Recio Caride A5, Añor S5, Gandini G6, Corlazzoli D4, Thibaud JL7, Matiasek K3, Blot S1. J Vet Intern Med. 2018 Nov; 32(6):2003-2012. doi: 10.1111/jvim.15316. Epub 2018 Oct 13. “Juvenile-onset polyneuropathy in American Staffordshire Terriers”.
2. Sheida Hadji Rasouliha1‡, Laura BarrientosID1,2‡, Linda Anderegg1‡, Carina Klesty3, Jessica Lorenz4, Lucie ChevallierID5, Vidhya Jagannathan1, Sarah Ro ¨schID6‡, Tosso LeebID1‡*. “A RAPGEF6 variant constitutes a major risk factor for laryngeal paralysis in dogs”. PLOS Genetics. https://doi.org/10.1371/journal.pgen.1008416. Octubre 24, 2019.
3. D. Fowler. NAVC Proceedings 2006, North American Veterinary Conference (Eds). Publisher: NAVC (www.tnavc.org). Internet Publisher: International Veterinary Information Service, Ithaca NY (www.ivis.org), Last updated: 11-Jan-2006. “Diagnosis and Treatment of Laryngeal Paralysis”. Western Veterinary Specialist Centre, Calgary, Alberta, Canada.
4.Ribó Ruiz, J; Sáez Cabello, J.Mª. “Infección por neospora caninum en un perro: descripción de un caso clínico”. Clínica veterinaria de pequeños animales (avepa) vol. 17, n.» 2,1997.

Laryngeal paralysis

Resume
Laryngeal paralysis is the inability of the muscles to abduct the arytenoid cartilages during inspiration. 

In dogs the most frequent presentation is acquired, it is more prevalent in large and giant breeds with an average age of 9-10 years. 

The etiology usually remains hidden. The traditional treatment is surgical and its objective is to increase the opening of the glottis.

A therapeutic alternative is presented with the placement of a closed siliconized laryngeal prosthesis (stent-Stening ®) in a dog.

Presentation of the case: Canine, Siberian Husky, male, 12 years old, presented for consultation at the Hospital Escuela, for episodes of respiratory difficulty in situations of stress or effort and changes in phonation.

At the general and particular objective examination, an inspiratory stridor was found as the only abnormality. Laryngeal paralysis was suspected and confirmed by laryngoscopy. At the request of the owners to avoid surgery, an experimental alternative was performed on canines (a technique similar to that used in laryngeal pathologies in humans) by placing a closed silicone prosthesis.(Stening ®)

Link original pap