Chapter 46 - Larynx Flashcards

1
Q

Larynx - the CAD is the major abductor or adductor muscle?

A

Abductor - it widens the laryngeal aperture

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2
Q

What are the muscles responsible for adduction of the larynx?

A

arytenoideus transverse muscle

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3
Q

What are the muscles responsible for adduction of the larynx?

A

1) arytenoideus transversus m.

2) thyroarytenoideus m.

3) cricoarytenoideus lateralis CAL

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4
Q

What is the main function of the crycothyroideus?

A

tenses vocal chords during vocalization)

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5
Q

Thyroid, cricoid and arytenoid are what type of cartilage?

A

Hyaline

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6
Q

Name the extrinsic muscles of the larynx

A

1) Cricopharyngeus

2) Thyrophayngeus

3) Thyrohyoideus

4) Sternothyroideus

5) Hyoepiglotticus

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7
Q

What is the nerve supply to the larynx?

A

Recurrent laryngeal nerve (branch of the vagus X)
cranial laryngeal nerve also branch of vagus (cricothyroideus vocalization)

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8
Q

What is the blood supply to the larynx? lymphatics?

A

caudal laryngeal artery

ascending pharyngeal artery

caudal laryngeal vein

ascending pharyngeal vein

Lymphatics :

  1. retropharyngeal
  2. cranial
  3. deep cervical lymph nodes
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9
Q

Corniculate, epligottis are what type of cartilage?

A

Elastic

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10
Q

Cricoarytenoid cartilage is which type of joint?

A

diarthrodial joints that allow
the arytenoid cartilages to rotate dorsolaterally during abduction,
and medially during adduction.

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11
Q

What are the different pathologies of the larynx (total 15)?

A
  1. Hemiplegia of the recurrent laryngeal nerve
  2. Vocal cord collapse
  3. Bilateral laryngeal collapse
  4. Right-sided laryngeal hemiplegia
  5. Cricopharyngeal-laryngeal dysplasia (4BAD)
  6. Collapse apex corniculate process
  7. Medial deviation of the aryepiglottic folds
  8. Arytenoid chondropathy
  9. Epiglotic entrapment
  10. Acute epiglotittis
  11. Subepiglotic cysts
  12. Dorsal epiglottic abcess
  13. Subepiglotic granuloma
  14. Epiglottic hypoplasia, flaccidity deformity
  15. Epiglottic retroversion
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12
Q

Laryngeal mucosa has sensory mechanoreceptors that detect which different stimuli (4 types)

A

transmural pressure changes,
airflow,
temperature,
and laryngeal motion

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13
Q

What are possible causes of damage to recurrent laryngeal nerve?

A

95% idiopathic some have cause

perivascular jugular vein

GP mycosis

trauma injuries in the neck

strangles abcessation

impingement by neoplasm

organophosphate toxicity

pant poisening

hepatic encephalopathy

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14
Q

Loss of large mylinated axons in left recurent laryngeal nerve. What type of fibers are lost?

A

Type 2

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15
Q

What is the % of muscle loss prior to clinical signs for left recurrent laryngeal nerve?

A

75%

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16
Q

What type of horses are predisposed RLN?

A

Larger breeds and younger horses (2-3 yold TB 2-8%) and draught horses (35%)

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17
Q

What are the methods of diagnosis of RLN?

A

history

physical exam

poor performance and inspiratory noise at work

palpable atrophy of the left CAD

Definitive dx made by endoscopy and gold standard is dynamic endoscopy

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18
Q

Describe grade I/IV of Havemeyer grade

A

All arytenoid cartilages movements are synchronus and symetric and full arytenoid cartilage abduction is achieved and maintained

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19
Q

Describe grade II.A

A

II Arytenoid cartilage movements are and asynchronous and/or larynx is asymmetric at times but full artyenoid cartilage abduction can be achieved and maintaned

A. Transient asynchronus, flutter, or delayed movements seen

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20
Q

Describe grade II B

A

Arytenoid cartilage movements asynchronous and/or asymetric at times but full arytenoid abduction is achieved and maintained

B. There is asymtry of the rima glottis due to lack of mobility of the affected arytenoid cartilage and vocal fold, but there are occasions typically after swallowing or nasal occlusion when full asymmetrical abduction is acheived and maintained.

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21
Q

Describe grade III A

A

Arytenoid cartilage movements are asynchronous and asymetric and full arytenoid cartilage abduction cannot be achieved and maintained

A. There is asymetry of the rima glottis much of the time due to lack of mobility of the arytenoid cartilage and vocal fold, but there are occasions typically after swallowing or nasal occlusion, when full symmetrical abduction is achieved but not maintained

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22
Q

Describe grade III B

A

There is obvious arytenoid abductor muscle deficit and arytenoid cartilage asymetry. Full abduction is never achieved.

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23
Q

Describe grade III C

A

There is marked but not total arytenoid abductor muscle deficit and arytenoid cartilage asymmetry with little arytenoid cartilage movement. Full abduction is never achieved.

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24
Q

Grade IV

A

complete immobility of the arytenoid cartilage and vocal fold

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25
erify the US
Fig 1: (a) Optimum position for the transducer. (b) Dorsal plane ultrasound image of the lateral aspect of a normal larynx. Note the position of the cricoarytenoideus lateralis and vocalis muscle (small arrowheads) between the thyroid cartilage (small arrows) and the arytenoid cartilage (large arrowhead). The cricoid cartilage (large arrow) is caudal to the thyroid cartilage. Rostral is to the left of the image and caudal to the right
26
Fig 3: (a) Transverse plane ultrasound of the lateral aspect of a normal larynx. Note the position of the cricoarytenoideus lateralis muscle (CAL) between the thyroid cartilage (arrows) and the arytenoid cartilage (arrowheads). The vocalis muscle is deep to the CAL, but the distinction between the muscles can often not be seen, as in this case. The arytenoid cartilage has a trumpet bell shape and the cricoarytenoideus lateralis and vocalis muscles have a striated appearance with heterogeneous echogenicity. Dorsal is to the left of the image and ventral is to the right (b) Position of the transducer
27
Fig 4: Dorsal plane ultrasound of the dorsolateral aspect of a normal larynx. This image is dorsal to that shown in Fig 1. The cricoarytenoid articulation (small arrowhead) is formed by the muscular process of the arytenoid (large arrowhead) and the dorsolateral cricoid cartilage (large arrow). The lateral portion of the cricoarytenoideus dorsalis muscle is imaged (small arrows). Rostral is to the left of the image and caudal is to the right
28
Fig 5: Transverse plane ultrasound of the ventral aspect of the cricoid cartilage (arrows) of a normal larynx. Left is to the right of the image and right is to the left
29
Fig 6: (a) Transverse plane ultrasound image of the ventral aspect of the thyroid cartilage (arrows) of a normal larynx at the level of the vocal folds (arrowheads). The movement of the vocal folds can be observed during respiration. Left is to the right of the image and right is to the left of the image. (b) Transducer position
30
Fig 7: Transverse plane ultrasound of the basihyoid bone (arrowheads) and the ceratohyoid bones (arrows) of a normal larynx, obtained with the transducer positioned ventrally. Left is to the right of the image and right is to the left
31
Fig 8: Comparison of echogenicity of the cricoarytenoideus lateralis and vocalis (arrows) and cricoarytenoideus dorsalis (arrowheads) musculature. Horses with recurrent laryngeal neuropathy have increased echogenicity and more homogeneous echogenicity of the cricoarytenoideus lateralis and cricoarytenoideus dorsalis muscles. Dorsal plane ultrasound images of the cricoarytenoideus lateralis muscle of (a) a horse with recurrent laryngeal neuropathy and (b) a normal horse. Transverse plane ultrasound images of the cricoarytenoideus lateralis and vocalis muscles of (c) a horse with recurrent laryngeal neuropathy and (d) a normal horse. Dorsal plane ultrasound images of the cricoarytenoideus dorsalis muscle of (e) a horse with recurrent laryngeal neuropathy and (f) a normal horse. In the dorsal plane images, rostral is to the left and caudal is to the right and in the transverse plane images, dorsal is to the left of the image and ventral is to the right
32
Fig 9: Transverse plane ultrasound image of the lateral aspect of the larynx of a horse with arytenoid chondritis. The arytenoid cartilage (arrows) is severely thickened with irregular margins and increased echogenicity in its interior. Dorsal is to the left of the image and ventral is to the right
33
Fig 10: Transverse plane ultrasound image of the lateral aspect of the larynx of a horse with laryngeal dysplasia. The thyroid lamina (arrowhead) extends dorsal to the muscular process of the arytenoid cartilage (arrow). Dorsal is to the left of the image and ventral is to the right
34
Fig 11: Dorsal plane ultrasound image of the lateral aspect of the larynx of a horse with laryngeal dysplasia. The thyroid cartilage (arrow) and the cricoid cartilage (small arrowhead) do not articulate. The cricoarytenoideus lateralis and vocalis muscles (large arrowheads) are positioned between the thyroid cartilage and cricoid cartilage in the gap between the two cartilages. Rostral is to the left of the image and caudal is to the right
35
What are the surgical options for RLN?
1. Prosthetic laryngoplasty 2. Ventriculectomy 3. Ventriculocordectomy 4. Reinnervation of the CAD muscle 5. Arytenoidectomy (partial or subtotal)
36
Describe prosthetic laryngoplasty
**10cm incision ventral** to **linguofacial v.,** extending caudally from **4 cm CRANIAL to ramus ofmandible** ´Separate linguofacial from **omohyoideus** ´Separate **cricopharyngeus and thyropharyngeus** to expose **muscular process & caudal border of cricoid** ´Sutures passed through the cricoid @ notch: ´Dorsal suture:**1cm lateral to dorsal ridge** & **2cm cranial to caudal borde**r and lateral suture: **1cm lateral to dorsal suture** ´Inspect tracheal lumen ´Forceps passed under **cricopharyngeus** to bring sutures cranially ´**Cricoarytenoideus articulation** **opened & curetted (+/- cut CAD insertion, PMMA)** ´Pass sutures through **muscular process from caudomedial to craniolateral** ´Sutures tied aim for Dixon Grade II – 88% of max. rima glottis area - corniculatetouches pharynx´LATERAL suturetied first ´Closure: ´Suture thyropharyngeus & cricopharyngeus (SC 2-0 vicryl) ´Suture fasciaof linguofacial vein to omohyoideus (SC 2-0 vicryl) ´Staple skin
37
Grades postop Dixon
38
What is in Bryne et al 2022 the % of surgeons performing standing laryngoplasty? What is the most common method one or 2 prostheses? What is the grade aimed?
35.9% standing method is 2 prostheses 82.8% Grade 2 swaged suture needle most common 76.6%
39
What are the needles for the cricoid?
Taper pointneedle ´No. 3 Martinuterine reverse cutting needle (less likely to break off in cartilage than acutting needle) ´Swaged onneedle Passerdevices: Scorpion Multifire, Fastpass
40
What are the needles for muscular process?
Reverse cutting No.6 Mayo ´No. 3 Martinuterine reverse cutting needle ´Jamshidi to make hole,wire loop passed through hole, prosthesis attached, pull back through hole
41
What are the most common sutures used?
´No. 5 Ti-Cron ´No. 5 Ethibond à braided polyester ´No. 5 FibreWire ´No. 2 FibreTape à polyblend ´Ethilon à nylon ´Lycra à polyurethane ´6mm stainlesssteel ´JP uses fibrewire & ethibond (1 suture ofeach)
42
What are the prosthesis variations?
´3mm bone trocar à reduces fissure formation in MP ´Aluminium button “toggle” in cricoid à similar strength regardless of shape of cricoid cartilage ´Securos EquineTie-Back System à tension & crimping device ´Titanium corks crew suture anchor in muscular process & washer @ cricoid -->↑forces to failure in vitro
43
Pressanto et al 2022 mentions that the use of polyblend tape suture in laryngoplasty had dusperior results to which suture?
Each larynx was randomly assigned to 1 of 4 groups: PL with polyblend tape suture (TigerTape), without (TT) or with a cannula (TTC) in the muscular process of the arytenoid cartilage, and PL with polyester suture (Ethibond), without (EB) or with a cannula (EBC). Biomechanical properties were **generally superior for the TTC** constructs tested under cyclical loading. The** TT and TTC constructs** failed at a **higher load than EB and EBC constructs.** The **cannula in TTC and EBC reduced the failure** at the **muscular process.**
44
Gray et al 2022 studies the effect of repeated freezing and thawing on suture of equine arytenoid and cricoid cartilages does it alter the suture pull-out strength?
No, it did not affect
45
Accordingly to Watkins et al 2022 does the knot elongation contributte to loss of arytenoid abduction when using polyester tape?
Yes and cyanoacrylate should be explored to limit elongation
46
What are the complications intra-operatively?
Hemorrage - linguofacial vein (during LA) - cranial thyroid artery/vein and caudal laryngeal artery and during separation of cricopharyngeus and thyropharyngeus Needle breakage (retrieve or leave it if doesn't penetrate laryngeal mucosa) Cut through the cartilage (insert suture in different location) Perforation of laryngeal mucosa (remove suture and replace new wire) Penetration of esophageal mucosa (when placing muscular process suture). - **isthmus of esophagus**
47
How do you solve a linguofacial vein puncture?
One efficient strategy in this rare but stressful situation is to immediately stop the bleeding by placing the little finger over the puncture site. Then lift the vein withthe finger and bluntly dissect it from the perivenous tissue. Place one or twocurved mosquito forceps at the base of the laceration andclose it using 3-0 or 4-0 absorbable monofilament such aspolydioxanone in a simple continuous pattern.
48
Pisano et al 2020 did ex vivo study of vagal branches at risk for iatrogenic injury during laryngoplasty which are they?
Branches of the pharyngeal plexus (PP) supplying cricopharyngeal muscle thyropharyngeal muscle and the esophagus
49
43% will coug himmediately post-op RLN, but should reduce over 7 – 10 days´14% developchronic cough (>6mths post-op). What are the causes? what is the tx?
Chronicc oughing may be related to:´Esophageal reflux; ´Crico- & thyropharyngeus muscles formcranial esophageal sphincter ´Damage tointernal branch cranial laryngeal nerve ´Suture throughadventitia of esophagus @ MP or cricoid ´Overabduction ´Failure ofcontralateral arytenoid & vocal fold to compensate ´ Fibrosis ´Treatment: **TIME, tie-fwd, remove prosthesis, vocal fold augmentation**
50
What other pathologies can cause dysphagia and coughing that should be rulled out?
resting endoscopic examination including examination of the trachea and GP should be performed to rule out other conditions such as: - 1arylower respiratory inflammation - guttural pouch diseases - arytenoid chondritis.
51
Luedke et al VS 2020 in management of postop dysphagia after LP or arytenoidectomy suggests 3 treatments which are..
1) **removal of laryngoplasty sutures** 2)**vocal fold augmentation** - inject through cricothyroid space polymetaacrylate** 3) **laryngeal tie fwd** 80% horses did VFA and improvement was 81% resolved dysphagia with 94% returning to some level of work
52
Complication postop RLN
+++ common complication is progressive loss of PLabduction Tracheal penetration of feed material/water/saliva is the 2nd major complication consequence is DDSP Seroma formation (delay discharge) Wound infection Coughing and dysphagia (usually weeks/months) after LP Arytenoid chondritis
53
If you have to perform a revision laryngoplasty what are the steps?
<2wkspost-op: remove original suture(s) & replace ´>4wks post-op: dense scar tissue, will bleed when dissecting to find cricoid &muscular process ´Cut knot atmuscular process but do not attempt to remove suture unless infected ´Place another laryngoplasty suture: ´If cartilage can be lifted away from ET tube, it is likely that abduction will be improved ´If not, it islikely the reoperation attempt will fail à try adifferent suture placement or recommend arytenoidectomy ´**NOTE: if removing suture for overabduction >4mths post-op, placing a new suture isunnecessary**
54
What is the prognosis for postop revision laryngoplasty?
70% - 80% have improved racing performance ´Outcome moresuccessful in non-racehorses
55
Postoperative care of laryngoplasty
confinement to a stall or a walk-in, walk-out yard for for 30 days feedand water placed at groundlevel hand-walkingis allowed for exercise5-6 wpost op exercised lightly or turned out in a small paddock or round pen Resumetraining
56
Article of Fitzharris et al VS 2019 mentions the outcomes of horses tx with removal of a laryngoplasty
Incidence is 3.5% Major reason in 90% was coughing/dyssphagia 75% returned to exercise
57
Accordingly to Broyles et al does the grade of laryngeal function prior laryngoplastly and ipsilat VC has an impact on racing?
Yes with grade III.2/III.3 were more likely to race postoperatively than horses grade IV. Horses grade IV took longer time to first race
58
Describe ventriculectomy through laryngotomy
GA - DR - Laryngotomy 6 cm ventral midline skin incison over the cricothyroid ligament of the larynx - exposure of the sternohyoideus and omohyoideus muscles that are split ID ot cricoid and thyroid cartilages - Place weitlaner retractor - incision of critothyroid ligament (clamp the vein caudal to cricoid!) - ID ventricle with finger and apply virgina roar burr and with rotation of 360º the mucosa is removed with the help of scissor close to the vocal cord
59
Describe ventriculocordectomy (Hobday procedure)
- Has largely replaced ventriculectomy ´Standing transendoscopic laser excision´Laryngotomy ´Do ventriculectomy first ´2mm widecrescent shaped wedge removed from leading edge of vocal fold ´Suture lateraledge of vocal fold to medial border of ventricle (limits haemorrhage)
60
Ventriculocordectomy improves airway mechanics around how much %
30%
61
Lean and all 2022 VS influence of unilateral and bilateral vocal cordectomy on ariflow across cadaveric equine larynges at different Rakestraw grades of arytenoid abduction. When grade A was present was there effect on translaryngeal impedance?
No, there was no effect on TLI following LVC or bilateral VC if grade A. But there was improvement TLI when the grade was B.
62
Name the grades
grades Rakestraw
63
What are the ideal candidates for ventriculocordectomy?
´Sport horses where primary complaint is respiratory noise ´Rac ehorse swith vocal fold collapse during exercise
64
What is the risk of ventriculocordectomy?
´Bilateral VC =↑ risk coughing & dysphagia
65
Postoperative management ventriculocordectomy
¡Topical administration a mixture of : 90% **250 mL of DMSO + 250 mL of glycerin + 50 mL prednisolone (25 mg/mL) + 500 mL nitrofurazone (Furacin)** ¡TMPS BID, 7 days ¡Corticosteroids (20 mg Dexamethasone IV, SID for 2–3 days) - Exercise restriction for 1 week - Endoscopy to assess if can return to paddock exercise or if additional rest - Training resumed in 60 d
66
Barakzai et al. 2019 Overground endoscopic findings and respiratory sound analysis in horses with RLN after unilateral laser ventriculocordectomy. Which energy had significant reduction in energy after surgery? Unilateral VC is useful for which grade of horses? Continuing noise may be present in which grade? What is the indicated surgery for grade C?
F2 sound Unilateral VC is ideal for grade B with reduction of sound F2 In grade C continuing noise may be ongoing due to other forms of dynamic obstruction Grade C bilateral VC + aryepliglotic fold resection +- laryngoplasty is better option than unilateral VC alone
67
Suarez-Fontes et al VS 2020 showed a new tecnhique using triangle-tip knife for transendoscopic ventriculocordectomy. Electrosurgery what is the principle? what it is the difference for electrocautery?
Electrosurgery: energy from the device to the tissue to heat up and cut/coagulate. Electrocautery: the device heats up to cut/coagulate tissue.
68
Advantages of monopolar electrosurgical triangle tip knife
Advantages: less expensive, less gear,special area, trained personnel, safety protocols required
69
Laryngeal reinnervation what are the candidates?
´Young horses with grade 3 laryngeal movement (respond sooner; 4-6mths vs Grade 4 à 6 – 12mths)
70
C1 emerges from where? Inserts where?
´C1 emerges from alar foramen à joins branches of C2 à descends overlarynx à divides into 2-3 branches à enters omohyoideus
71
Omohyoideus is an acessory respiratory muscle that is active when?
on respiration
72
How much time it takes to reinnervation to take place?
´Reinnervation takes ~ 3mths, backto training @ 4mths, check abduction with C1 nerve stim @ 5-6mths ´Most work in4-5mths à if noarytenoid abduction by 9mths = failure
73
Describe the nerve implantation tx
´10cm incision ventral to linguofacial vein ´Separate linguofacial v from omohyoideusm´C1/C2 nervei dentified with nerve simulator à branches found in dorsomedial omohyoideus muscle belly ´Dissect out 1- 2 branches (ones producing strongest OH contraction with nerve stim) &cut with #15 blade ´Cricopharyngeus myectomy toexpose CAD ´3 x cuts madein tip of nerve with 20g needle à multiplesites for axon sprouting´ Reverdin needle passedlateral to medial through CAD ´Nerve attached to Reverdin needle with 4-0 absorbable monofilament suture 'Nerve implanted in CAD tunnel by retraction of needle ´Distal end of nerve secured to CAD with 4-0 absorbable monofilament nylon ´Close myectomy (3 x interrupted cruciates, 2-0 monocryl)
74
What are the complications of this surgery?
Seroma and incisional infeciton
75
Prognosis accordingly to Rossignol et al 2018 about reiinervation
91.6% resulted in reinnervation (11/12) 64% improvement of exercising grade (9/14) within 12 months of sx
76
Name the instrument
Nerve forceps with blunt teeth to hold the nerve without crushing
77
Name the instrument
Reverdin needle for reinervation tx
78
Name the instrument
Bipolar nerve locator
79
Ariane Campos et al 2022 EVJ study a new nerve grafting, which nerve? that nerve provides innervation to which muscle
Ventral branch of the spinal acessory nerve. Motor innervation to the sternomandibularis (SM) muscle
80
The contraction of the sternomandibularis muscle coincides with inspiration or expiration? at what time?
Inspiration at gallop
81
At rest the sternomandibulares can also be stimulated, at which situation?
When grazing it is activated 7 times more than when eating out hay net or stable feeder
82
Which type of fiber is activated during feeding and exercise?
**Type I fiber** 2.5 times higher than type II fiber activity
83
Arytenoidectomy has 2 types of surgery name them and explain the difference
Subtotal muscular process + corniculate cartilage removal Partial removal of muscular process --> superior
84
Describe the surgical tx of PARTIAL arytenoidectomy
Tracheostomy before standing Laryngotomy - **10 cm incision sternohyoideus/omohyoideus **- split **cricothyroid ligamen**t - ´**Dorsally based U-shaped mucosal incision** over arytenoid and elevate mucosal flap, exposes arytenoid ´Soft tissues dissected off lateral surface of arytenoid ´Muscular process transected with heavy scissors ´Cartilage removed by cutting the cricoarytenoid joint caudally and the corniculate mucosarostrally ´Ventriculocordectomy performed ´Vertical mucosal incisions closed (SI 2-0 PDS) à smoother luminal surface = less post-op granulation tissue ´Cricoid opposed by suturing soft tissues, DO NOT PUT SUTURE THROUGH CARTILAGE (SI 0PDS)
85
When do you have to reverify the surgical result?
4 weeks postop
86
Gay et al VS 2019 studied the partial arytenoidectomy in standing horses with sedation and LA. What was the main cause of surgery?
13 horses had unilateral left-sided recurrent laryngeal neuropathy and 1 horse had bilateral RLN. 5 horses had previous failed prosthetic laryngoplasty Left-sided partial arytenoidectomy without mucosal closure was successfully completed in all horses under sedation + LA No sutures - all healed by 2nd intention 75% horses returned to athletic use (9/12) without respi noise
87
Complications of partial arytenoidectomy?
Dyspnoea à oedema/blood trapped under sutured mucosal flap ´Do not suturethe ventral aspect of the mucosal flap à leave open todrain ´Leave trach inuntil airway patency confirmed ´Dysphagia à ~1/3rd of horses ´Coughing à common during eating à feed onground ´Granulation tissue à ~15% of horses1mth post-op (LASER) ´Laryngeal cartilage mineralization à 5% of horses,useless for work
88
What is the incidence of arytenoid chondrotpathy?
0.6-2.4%
89
How do you perform the diagnosis of arytenoid chondropathy?
Endoscopy : differences in the shape or size of thecorniculate process, mucosal disruptions and/or granulation tissue on the medial (luminal) surface of thearytenoid, and displacement of the palatopharyngeal arch lateral to the corniculate process
90
Arytenoid chondropathy is a pathology of one or both arytenoids and can mimic which laryngeal disease?
typically asequela of infection. This disease can mimic RLN if thechondropathy is mild.
91
What are the clinical signs Arytenoid chondropathy?
It can be acute or chronic and clinical signs is **respiratory noise dyspneia**
92
What treatment in case of mucosal erosion, ulcers?
Broad-spectrum antibiotics, NSAIDs, and pharyngeal washes are recommended for 10 to 14 days.If not treated it will progress into granuloma
93
What is the surgical treatment arythenoid chondropathy?
local excision and drainage using endoscopi cscissors, laser therapy or local curettage If cartilage function is significantlyimpaired and/or the laminar portion of the arytenoid cartilage is thickened sufficiently (chronic form),surgical removal of the affected arytenoid cartilage is usually necessary Arytenoidectomy (partial or subtotal) Permanent tracheostomy
94
Postoperative care
Food withheld 24 hoursInitially have hay on the floor until no cough Remove tracheostomy tube Stallrest4-6 weeks
95
Complications following surgery
Dyspnea/ dysphagia 32% reported with food and water falling through nares Coughing formation of intralaryngeal granulation tissue was identified 1 month after surgery in 17% of horses treated with partial arytenoidecotomy Any excessive tissue must be removed with laser
96
Mucosal granulomas are typical in which breeds? what is the etiology?
Young Throroughbred Bilateral kissing lesions of unknown cause
97
Diagnosis
Arytenoid chondropathy abnormally thickened and non-abducted left arytenoid, causing narrowing of the glottis.
98
# What is the recommended tx? What is the recommended tx for arytenoid chondropathy?
¡Broad-spectrum antibiotics, NSAIDs, and pharyngeal washes are recommended for 10 to 14 days ¡Ifthere are any masses developing, removal with laser is recommended a **400 to 600 μm fiber through biopsy channel**
99
Prognosis for granulomas?
Depends on severity
100
Vocal cord collapse can be diagnosed in static endoscopy?
No usually is in high-speed exercise using videoendoscope
101
The vocal cord is stabilized by which muscle?
cricothyroid muscle
102
What is the grade of RLN observed in vocal chord collapse? what is the treatment?
Treatment is bilateral ventriculocordectomy
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What are the causes of bilateral laryngeal collapse/paralysis ?
-organophosphate toxicity -Equine protozoal myeloencephalitis -Hepatic dysfunction/encephalopathy -Lead toxicity (Pb) -After GA -Australian stringhalt
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What are the clinical signs of bilateral laryngeal collapse/paralysis ?
Horses don't tolerate any exercise and loud inspiratory noise when in distress even at rest emergency tracheostomy might be required
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What are the treatments you can propose to the owner in bilateral laryngeal paralysis?
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Diagnosis
Bilateral laryngeal collapse
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Diagnosis
Laryngeal dysplasia arrow palatopharyngeal arch visible over both arytenoid - (branchial arch defect),
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What is laryngeal dysplasia?
is a congenital abnormality of the laryngeal cartilages that can alsomimic RLN because of the inability to fully abduct thearytenoid; however, this is a congenital malformation ofmultiple laryngeal cartilages
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Laryngeal dysplasia can have endoscopic appearance of which laryngeal disease?
appearance similar to RLN in that a single arytenoid may not be able toachieve full abduction.
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What is the most affected side of laryngeal dysplasia? what is a typical sign visible on endoscopy?
- right side is affected the structure of the arytenoids is not symmetrical +++ R side - Open esophagus -Palatopharyngeal arch is draped over the apex of the affected arytenoid
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Figure 46-2. Endoscopic image of the larynx of a horse with grade 4 recurrent laryngeal neuropathy at rest.
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Figure 46-3. Endoscopic image of the larynx of a horse with grade 4 recurrent laryngeal neuropathy during high-speed exercise, showing complete collapse of the left arytenoid cartilage and vocal fold on inspiration.
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Figure 46-4. Illustration of the correct placement of the laryngoplasty suture and the resultant effects on arytenoid position. (A) Lateral view of single prosthetic suture in place and tied. (B) Dorsal view of the larynx, showing configuration of the laryngoplasty suture. (C) Endoscopic image of a larynx with grade 4 recurrent laryngeal neuropathy before laryngoplasty. (D) Endoscopic appearance of the larynx after laryngoplasty with the left arytenoid cartilage in moderate abduction (Dixon grade 2)
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(A) Placement of the prosthesis behind the caudal border of the cricoid cartilage and exiting through the dorsal portion of the cartilage. (B) Placement of the prosthesis through the muscular process of the arytenoid cartilage from a caudomedial to craniolateral direction. Alternative technique:
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(C) both strands of sutures are passed through separate titanium buttons (acting hereinto as a toggle), prior to placing the suture through the cricoid cartilage. (D) Cadaver view showing the proper docking of the button on the ventral surface of the cricoid cartilage. (E) Placement of the prosthesis through the muscular process of the arytenoid cartilage parallel to cricoarytenoid joint.
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Figure 46-6. Illustration of the laryngoplasty techniques. Traditional technique:(F) Note position of isthmus of esophagus and its adventitia over the muscular process (*).
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Grade 1 Figure 46-7. Endoscopic representation of intra- or postoperative endoscopic laryngeal grade associated with laryngoplasty as described by Dixon et al.77 Grade 1: Endoscopic image of an overabduction of the left arytenoid cartilage owing to excessive tension of the prosthetic suture. Grade 2: 80% to 90% abduction (generally the targeted abduction in racehorses). Grade 3: Abduction slightly about resting position (generally the targeted abduction in sport horses and draft horses). Grade 4: Abduction below the normal resting position of an arytenoid cartilage. Grade 5: Complete loss of abduction with arytenoid positioned on or near the midline.
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Grade 2 Figure 46-7. Endoscopic representation of intra- or postoperative endoscopic laryngeal grade associated with laryngoplasty as described by Dixon et al.77 Grade 1: Endoscopic image of an overabduction of the left arytenoid cartilage owing to excessive tension of the prosthetic suture. Grade 2: 80% to 90% abduction (generally the targeted abduction in racehorses). Grade 3: Abduction slightly about resting position (generally the targeted abduction in sport horses and draft horses). Grade 4: Abduction below the normal resting position of an arytenoid cartilage. Grade 5: Complete loss of abduction with arytenoid positioned on or near the midline.
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Grade 3 Figure 46-7. Endoscopic representation of intra- or postoperative endoscopic laryngeal grade associated with laryngoplasty as described by Dixon et al.77 Grade 1: Endoscopic image of an overabduction of the left arytenoid cartilage owing to excessive tension of the prosthetic suture. Grade 2: 80% to 90% abduction (generally the targeted abduction in racehorses). Grade 3: Abduction slightly about resting position (generally the targeted abduction in sport horses and draft horses). Grade 4: Abduction below the normal resting position of an arytenoid cartilage. Grade 5: Complete loss of abduction with arytenoid positioned on or near the midline.
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Grade 4 Figure 46-7. Endoscopic representation of intra- or postoperative endoscopic laryngeal grade associated with laryngoplasty as described by Dixon et al.77 Grade 1: Endoscopic image of an overabduction of the left arytenoid cartilage owing to excessive tension of the prosthetic suture. Grade 2: 80% to 90% abduction (generally the targeted abduction in racehorses). Grade 3: Abduction slightly about resting position (generally the targeted abduction in sport horses and draft horses). Grade 4: Abduction below the normal resting position of an arytenoid cartilage. Grade 5: Complete loss of abduction with arytenoid positioned on or near the midline.
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Grade 5 Figure 46-7. Endoscopic representation of intra- or postoperative endoscopic laryngeal grade associated with laryngoplasty as described by Dixon et al.77 Grade 1: Endoscopic image of an overabduction of the left arytenoid cartilage owing to excessive tension of the prosthetic suture. Grade 2: 80% to 90% abduction (generally the targeted abduction in racehorses). Grade 3: Abduction slightly about resting position (generally the targeted abduction in sport horses and draft horses). Grade 4: Abduction below the normal resting position of an arytenoid cartilage. Grade 5: Complete loss of abduction with arytenoid positioned on or near the midline.
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Figure 46-10. Schematic illustration of the ventriculectomy technique with the horse in dorsal recumbency. (A) The “roaring” burr is placed into the laryngeal ventricle and rotated so that the head of the burr engages the mucosa of the laryngeal saccule. (B) When the saccule is firmly engaged, it is everted into the lumen of the larynx by steadily pulling on the burr. (C) A large hemostat is placed across the saccule immediately adjacent to the vocal fold, and the burr is removed. (D) The saccule is completely excised using Metzenbaum scissors adjacent to the hemostat.
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Figure 46-11. Schematic illustration of the nerve implantation technique. (A) The origin and insertion of the left first/second (C1/C2) cervical nerves into the omohyoideus muscle is shown. This nerve serves as the donor for reinnervation of CAD muscle in horses with recurrent laryngeal neuropathy. (B) The C1/C2 cervical nerves to the omohyoideus muscle, which has been retracted with Allis tissue forceps. (C) After sharp transection of the nerve, a myectomy of the cricopharyngeus muscle is done to expose the atrophied CAD muscle. (D) The nerve is placed on a tongue depressor and three cuts are made with a 20-gauge needle on its side to allow multiple sites for axonal sprouting.
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E) A suture is placed to the leading edge of the nerve and secured to a previously placed Riverdin needle. (F) The nerve is guided through the CAD muscle and the distal end is secured to the CAD by a 4-0 suture. (G) The myectomy site is closed with three to four cruciate sutures with 00 Monocryl. (H) Intraoperative view. Insertions of three C1/C2 nerve branches at the dorsomedial aspect of the muscle omohyoideus muscle.
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Figure 46-13. Videoendoscopic image of the larynx showing rostral displacement of the palatopharyngeal arch in a case of fourth branchial arch defect. The palatopharyngeal tissue is covering the apical portions of the corniculate processes, and both arytenoid cartilages show very limited abduction
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Figure 46-14. (A) Videoendoscopic appearance of medial deviation of the membranous portions of the aryepiglottic folds during high-speed treadmill exercise. (B) Immediate postoperative endoscopic appearance of the membranous portions of the aryepiglottic fold after excision through a laryngotomy. (
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Figure 46-16. Endoscopic appearance of arytenoid chondropathy, showing incomplete abduction of the left arytenoid cartilage and granulation tissue on the medial surface of the body of the arytenoid at the entrance to a fistula.
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Figure 46-17. Endoscopic scissors are being used to remove a granuloma on the medial surface of the left arytenoid cartilage.
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Figure 46-18. Schematic representation of a lateral view of the arytenoid cartilage, demonstrating the portions of the cartilage that are removed (unshaded) during subtotal and partial arytenoidectomy.
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Figure 46-21. Schematic illustration of partial arytenoidectomy technique. (A) Beginning at the apex of the corniculate process and 2 mm caudal to the rostral surface, a mucosal incision is made that extends ventrad then caudad and finally dorsad around the outline of the arytenoid cartilage (dotted line). (B) The mucosa is firstly elevated from the arytenoid cartilage using a scalpel then a periosteal elevator, which exposes the laminar portion of this cartilage. The cartilage is then freed from its deep attachments using blunt dissection, staying close to the cartilage. The muscular process is transected with heavy scissors or a scalpel and the dissected cartilage is removed. Then the ventricle and vocal fold are removed. (C) All remaining mucosal incisions are apposed with simple continuous or interrupted sutures of 2-0 polydioxanone, taking care to remove any redundant tissue during closure. The ventral part of the incision is not sutured to allow postoperative drainage.
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Figure 46-24. Endoscopic appearance of epiglottic entrapment showing a thin entrapping membrane where the outline of the epiglottis is still visible.
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Figure 46-25. Endoscopic appearance of epiglottic entrapment where the aryepiglottic fold partially entraps the epiglottis and is intermittently relieved by swallowing.
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Figure 46-27. Endoscopic appearance of epiglottic entrapment with severe mucosal ulceration, showing exposed granulation tissue and significantly obstructing the view of the larynx.
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Figure 46-23. Endoscopic appearance of bilateral mucosal ulcerations on the medial surface of the arytenoid cartilages.
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Figure 46-27. Endoscopic appearance of epiglottic entrapment with severe mucosal ulceration, showing exposed granulation tissue and significantly obstructing the view of the laryn
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Figure 46-28. Laser guide is being used to protect the epiglottic cartilage during laser treatment of an epiglottic entrapment. (A) Horizontal incision is first made from right to left to allow penetration of the guide through the membrane. (B) A cauda-rostral incision is then made to relieve the entrapment. (Horse in Figure 46-24.)
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Figure 46-29. (A) Endoscopic appearance of a curved bistoury dividing on the midline an entrapping membrane via an oral approach. Note the glossoepiglottic fold ventral to the epiglottis. (B) Guarded hook being used to divide on the midline an entrapping membrane via a nasopharyngeal approach.
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Figure 46-30. Endoscopic appearance of a thick, ulcerated epiglottic entrapment in a Thoroughbred racehorse. Surgical correction was achieved by excising the central third of the aryepiglottic fold through a laryngotomy.
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Figure 46-31. Endoscopic appearance of acute epiglottitis shows the typical edema and thickening of the epiglottis with this condition.
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Figure 46-32. Endoscopic appearance of a subepiglottic cyst in a foal; the cyst was resected via laryngotomy.
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What are the diagnositc methods of equine laryngeal dysplasia?
Palpation Exercise endoscopy radiography US MRI exploratory surgery
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Which structures are absent in laryngeal dysplasia?
Wing of the thyroid is displaced dorsally so on** palpation **you don't have a prominent **muscular process**
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What is the palpable deficit in 4BAD?
palpable deficit of the thyroid wing on oneor both sides, or an easily palpated gap between the cricoid and thyroidcartilages because of the absence or atrophy of the cricothyroid muscle.
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The fourth branchial arch gives origin during embryo to which structureS?
1. Thyroid 2. Circoarytenoid articulation 3. Cricoid 4. Cricothyroideus 5. Thyropharyngeus 6. Cricopharyngeus
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Right sided laryngeal hemiplegia neuropathy is rare in horses is laryngoplasty a solution like the left laryngeal hemiplegia?
High % of failure in RLN for laryngoplasty
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Treatment recommended for right sided laryngeal hemiplegia?
Partial arytenoidectomy when obstruction by arytenoid cartilage is noted Some horses can respond to laryngoplastyif the thyroid lamina is removed and the cricoid cartilage is not involved inthe deformity, but the outcome of the surgery is unpredictable Laser resection of the palatopharyngealarch isuseful when dynamic collapse of the palatopharyngeal
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Diagnosis?
4BAD
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Bowkett -Pritchard EVJ 2022
Computed tomographic transverse reconstructions of the larynx using a (a) bone setting (Window Level 800 HU, WindowWidth 2800 HU) and (b) soft tissue setting (Window Level 350 HU, Window Width 80 HU). These settings apply to all figures. The horse'sright side is on the left of the image. (a) The median crest of the cricoid cartilage (block arrow) is rotated to the right and the ventral aspect ofthe larynx to the left, with displacement of the CAD muscles (asterisks). There is hypoplasia of the right cricopharyngeus muscle; the normalleft cricopharyngeus muscle is indicated (arrow). Cricoid cartilage mineralisation is present (arrowheads). (b) The right thyroid cartilage isabnormally elongated on the right and the dorsal aspect (arrowhead) is dorsal to the muscular process of the right arytenoid cartilage (blockarrow)
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Bowkett -Pritchard EVJ 2022
FIGURE 4 (a) Computed tomographic median reconstruction of the larynx using a soft tissue setting. (b) Laterolateral radiograph of the larynx. Rostral is to the left in both images. In (a) and (b) a large oesophageal gas column is visible (asterisk). The palatopharyngeal arch (large arrow) is displaced rostrally, positioned rostral to the corniculate process of the arytenoid cartilages (small arrow). Thyroid (open arrowheads) and cricoid cartilage (closed arrowheads) mineralisation is seen in (b)
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What is a typical sign of dysplasia on CT and radio accordingly to Bowkett-Pritchard et al 2022?
**Mineralisation of the thyroid and cricoid **cartilages were visibleon CT and radiography
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Ventroaxial collapse of apex of corniculate process does it have treatment?
no reported treatment is available forthis condition, and further postmortemstudies will be necessary to elucidate the anatomic pathology involved
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Diagnosis
Ventroaxial luxaiton into lumen of rima glottis of corniculate process Barakzai et al 2007 Prevalence 5%
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Diagnosis
Axial deviation of aryepiglottic folds ADAF
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When does the axail deviation of aryepiglottic folds ADAF occur?
occurs during **maximal exertion**
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Clinical signs of medial deviation of aryepiglottic folds ADAF
Can occur in horses wit RLN and DDSP Abnormal respiratory noise Exercise intolerance Often bilateral, if not, right sided
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What is the treatment for eviation of aryepiglottic folds ADAF?
Laser removal or through laringotomy
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When does it occur epiglotic entrapment? What is the cause for the entrapment?
*occurs when the loose subepiglottic mucous membrane becomes positioned abovethe dorsal epiglottic surface and then appears continuous with thearyepiglottic folds
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What are the clinical signs of epiglottic entrapment?
*abnormal respiratory noise and often, butnot always, exercise intolerance, particularly in Thoroughbred and Standardbredracehorses sometimes incidental finding
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Endoscopy allows to make the diagnosis. Are the EEP more persistent or intermittent? thick or thin? wide or narrow? ulcerated or non-ulcerated?
*Most epiglottic entrapments (97%) are persistent, most (98%) are thick, most (97%)are wide 45% are ulcerated
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What other concurrent diseases can be present with epiglottic entrapment?
Epiglotic Hypoplasia and flaccidity
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What is the treatment for epiglottic entrapment?
***transendoscopic diode laser midline division,* *** trans nasal over guide is technique of choice** But **transoral midline **division with a **curved bistoury,** **transendoscopic electro surgical **midline (electrocautery) division, surgical excision through a **laryngotomy or a pharyngotomy.**
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Describe the technique for transendoscopic diode laser
the diode laser, a 400- to 600-μmfiber a laser guide (Equine Fibre Laser guide)placed underneath the entrapping membrane Total energy used should be less than1000 J
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What is the reentrapment rate?
4%
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What is the postop care for transendoscopic diode laser ? When can start to work?
1-2 weeks rest, endoscopy every week until repaired Can return to work within 6-8 weeks TMPS, Pbz, corticosteroids(dexamethasone 0.04 mg/kg) and throat spray
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What can be a consequence from this surgery (transendoscopic diode laser for epiglotic entrapment)?
DDSP
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Beste et al 2019 VS use a transedoscopic silicone-cover laser guide and diode laser in 29 horses, what was the outcome for the procedure?
93% return to racing
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Beste et al 2019 VS use a transedoscopic silicone-cover laser guide what was the advantage of using silicone cover?
Is better than the metallic because prevents heating of the guide and risk of collateral damage Easy, mild post op complications Good prognosis
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Curtiss et al 2020 mentions that if there is right arytenoid abnormality that the prognosis is... and that one sex is more predispose than other, which one?
Bad prognosis if right arytenoid side was affected along epiglottic entrapment it was associated with never racing Female > males
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Curtiss et al 2020 RAce performance following epiglottic entrapment surgery in THO yearlings is there a difference between tx and non tx horses in racing?
No. Horses tx had similar results to non-tx horses
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excessively thickened, ulcerated, orfibrotic-appearing entrapping membrane is present in approximately 5% ofhorses with epiglottic entrapment, and often these horses have severe.....
epligottic hypoplasia
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What is the product injected in case of thick membrane and swollen tissue?
Betamethasone
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Acute epligottiis is characterized by mucous membrane that is...
extensive red or purple swelling of the mucous membrane
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What is the tx for acute epiglotitis ?
*Exercise should be discontinued. *Most horses respond well tosystemic NSAIDs and antimicrobial medications and pharyngeal sprays containing antiinflammatorymedication
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Many recover completely from acute epiglotitis and return to work but long-term complications occur in 50% of the cases. Name them
include epiglottic deformity, epiglotticentrapment, or intermittent or persistent dorsal displacement of the softpalate
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Subepiglottic cysts what are the clinical signs?
coughing, dysphagia, aspiration pneumoniamayalso be acquiredoccasionallydx in older horses with noprevious history of respiratory tract problems
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What is the tx for subepiglottic cyst?
Either GA and removal through laringotomy with retroversion of the epiglottis and mucosal incision left to heal by 2nd intention or Surgical removal with laser tractionis placed on the mucosa and the underlying cyst with 600-mm long bronchoesophagealgrasping forceps fusiformincision intothe mucosaover the cystis made transendoscopicallywith 600 μm 8to 12 W of power Cyst membraneis then submucosally excised with the laser
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What is the postop treatment of subepiglottic cyst tx?
¡Corticosteroids+ NSAIDs + pharyngeal sprays - exerciseis restricted until the pharynx appears endoscopically normal Usually 21 days
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What other pathology can be confused with subepiglotic cyst?
Subepiglottic granulomas that originate form acute ulceration of the AE fold on the ventral aspect of the epiglottis
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What is the treatment and postop ?
abscess can be incised and drainedt ransendoscopically with a contact diodelaser Abcess should be decompressed, debrided and lavaged stall confinement + exercise restrictedto hand-walking. Pbz , TMPS 3 days appears healed by 10 days postoperatively horses resumed normal exercise without recurrence of the abscess Epiglottic deformity might be noted
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What is the clinical sx of subepiglottic granulomas?
- coughing, - exercise intolerance ofvarying degrees - occasionally dysphagia - poor performance - intermittentdorsal displacement of the soft palate may be suspected.
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Dorsal epiglottic abcess
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What is the treatment of suepiglottic granulomas?
AB and AINS for 4 to 6 weeks usually works when ulcers do not heal the granulation increments when the horse goes back to work
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What is the tx advised in case of enlargement of granulation tissue?
excision through the nasopharynx,oropharynx, or through a ventral laryngotomy Sharp through laryngotomy may not resolve the problem Sterilization with laser cautery of the surface indicated
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Epiglottic hypoplasia, falccidity, deformity
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What diagnostic methods can provide additional information about epiglottic features and their relationship to adjacent pharyngeal structures?
**Lateral laryngeal radiograph **and **contrast pharyngography **may provide additional information regarding thyroepiglottic length, epiglottic thickness and contour, and the relationship of the epiglottis to other adjacent pharyngeal structures.
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What is the prognosis for horses with severe epiglottic hypoplasia or deformity resulting in persistent dorsal displacement of the soft palate?
Severe epiglottic hypoplasia or deformity associated with persistent dorsal displacement of the soft palate is associated with a **guarded to poor prognosis** for optimal exercise potential.
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Why is epiglottic hypoplasia scrutinizedduring prepurchase endoscopic examinations in yearling Thoroughbreds?
Because *epiglottic hypoplasi*a in adult horses is thought to** contribute to epiglottic entrapment** and** intermittent DDSP**
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Is there a correlation with epiglottic shape and racing outcome?
Yes, correlation with epiglottic shapeand appearance and racing outcome was found
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Do adults and yearlings have a difference between the appearance of epiglottis?
YES *Compared with adult horses, yearlings normally have a shorter, narrower, and moreflaccid-appearing epiglottis, and judgments about epiglottic appearance shouldbe reserved until the horse reaches maturity, except in very severe cases.
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diagnosis
Epiglottic retroversion
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What is epiglottic retroversion?
condition where the epiglottis assumes a position dorsal to the soft palate and retroverts into the opening ofthe glottis during inspiration and returns to its normal position with each expiration
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What is needed to confirm the diagnosis?
* dynamic or treadmill video endoscopyis necessary to confirm the diagnosis
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Curtiss and Parent VS 2019 describe 2 cases of horses submitted to epiglottopexy. Describe the technique
Peni, pbz, dexa, GA DR and neck extended **Gunther oral speculum** to pass videoendoscope into caudal oropharynx Use** bronchoesophageal forceps to place epiglottis** into the oral cavity to assess suture placement **Pharyngotomy - ventral incision between cricoid and basihyoid** Incision of omohyoideus and weitlaner retractor placed Blunt dissection to expose rostroventral aspect of thyroid cartilage to the base of the epiglottis N5 braided polyester suture passed through thyroid cartilage in dorsal to ventral direction 0.5 cm to the right side of the midline and 1 cm caudal to the most rostral part of the ventral wing - suture is passed horizontal plane from R to L dorsal to the **HYOEPIGLOTTICUS** muscle wihtin the fascia between the muscle and epiglottic cartilage jsut rostral to the rostral edge of thyroid cartilage Endoscopy allows to verify that mucosa was not passed and suture are placed in subepiglottic region tied together so that epiglottis has ventral tension
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What are the muscles reponsible for normal position of epiglottis?
hyoepiglotticus an geniohyoid muscles of the larynx
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What is the most common complication during epiglottopexy?
44% dyspnea from suture failure