Chapter 46 - Larynx Flashcards
Larynx - the CAD is the major abductor or adductor muscle?
Abductor - it widens the laryngeal aperture
What are the muscles responsible for adduction of the larynx?
arytenoideus transverse muscle
What are the muscles responsible for adduction of the larynx?
1) arytenoideus transversus m.
2) thyroarytenoideus m.
3) cricoarytenoideus lateralis CAL
What is the main function of the crycothyroideus?
tenses vocal chords during vocalization)
Thyroid, cricoid and arytenoid are what type of cartilage?
Hyaline
Name the extrinsic muscles of the larynx
1) Cricopharyngeus
2) Thyrophayngeus
3) Thyrohyoideus
4) Sternothyroideus
5) Hyoepiglotticus
What is the nerve supply to the larynx?
Recurrent laryngeal nerve (branch of the vagus X)
cranial laryngeal nerve also branch of vagus (cricothyroideus vocalization)
What is the blood supply to the larynx? lymphatics?
caudal laryngeal artery
ascending pharyngeal artery
caudal laryngeal vein
ascending pharyngeal vein
Lymphatics :
- retropharyngeal
- cranial
- deep cervical lymph nodes
Corniculate, epligottis are what type of cartilage?
Elastic
Cricoarytenoid cartilage is which type of joint?
diarthrodial joints that allow
the arytenoid cartilages to rotate dorsolaterally during abduction,
and medially during adduction.
What are the different pathologies of the larynx (total 15)?
- Hemiplegia of the recurrent laryngeal nerve
- Vocal cord collapse
- Bilateral laryngeal collapse
- Right-sided laryngeal hemiplegia
- Cricopharyngeal-laryngeal dysplasia (4BAD)
- Collapse apex corniculate process
- Medial deviation of the aryepiglottic folds
- Arytenoid chondropathy
- Epiglotic entrapment
- Acute epiglotittis
- Subepiglotic cysts
- Dorsal epiglottic abcess
- Subepiglotic granuloma
- Epiglottic hypoplasia, flaccidity deformity
- Epiglottic retroversion
Laryngeal mucosa has sensory mechanoreceptors that detect which different stimuli (4 types)
transmural pressure changes,
airflow,
temperature,
and laryngeal motion
What are possible causes of damage to recurrent laryngeal nerve?
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
Loss of large mylinated axons in left recurent laryngeal nerve. What type of fibers are lost?
Type 2
What is the % of muscle loss prior to clinical signs for left recurrent laryngeal nerve?
75%
What type of horses are predisposed RLN?
Larger breeds and younger horses (2-3 yold TB 2-8%) and draught horses (35%)
What are the methods of diagnosis of RLN?
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
Describe grade I/IV of Havemeyer grade
All arytenoid cartilages movements are synchronus and symetric and full arytenoid cartilage abduction is achieved and maintained
Describe grade II.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
Describe grade II B
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.
Describe grade III 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
Describe grade III B
There is obvious arytenoid abductor muscle deficit and arytenoid cartilage asymetry. Full abduction is never achieved.
Describe grade III C
There is marked but not total arytenoid abductor muscle deficit and arytenoid cartilage asymmetry with little arytenoid cartilage movement. Full abduction is never achieved.
Grade IV
complete immobility of the arytenoid cartilage and vocal fold
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
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
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
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
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
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
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
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
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
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
What are the surgical options for RLN?
- Prosthetic laryngoplasty
- Ventriculectomy
- Ventriculocordectomy
- Reinnervation of the CAD muscle
- Arytenoidectomy (partial or subtotal)
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 border 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
Grades postop Dixon
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%
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
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
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)
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
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.
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
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
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
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.
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
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
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.
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
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
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
What is the prognosis for postop revision laryngoplasty?
70% - 80% have improved racing performance ´Outcome moresuccessful in non-racehorses
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
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
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
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
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)
Ventriculocordectomy improves airway mechanics around how much %
30%
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.
Name the grades
grades Rakestraw
What are the ideal candidates for ventriculocordectomy?
´Sport horses where primary complaint is respiratory noise
´Rac ehorse swith vocal fold collapse during exercise
What is the risk of ventriculocordectomy?
´Bilateral VC =↑ risk coughing & dysphagia
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
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
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.
Advantages of monopolar electrosurgical triangle tip knife
Advantages: less expensive, less gear,special area, trained personnel, safety protocols required
Laryngeal reinnervation what are the candidates?
´Young horses with grade 3 laryngeal movement (respond sooner; 4-6mths vs Grade 4 à 6 – 12mths)
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
Omohyoideus is an acessory respiratory muscle that is active when?
on respiration
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
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)
What are the complications of this surgery?
Seroma and incisional infeciton
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
Name the instrument
Nerve forceps with blunt teeth to hold the nerve without crushing
Name the instrument
Reverdin needle for reinervation tx
Name the instrument
Bipolar nerve locator
Diagnosis
Arytenoid chondropathy abnormally thickened and non-abducted left arytenoid, causing narrowing of the glottis.
Diagnosis
Bilateral laryngeal collapse
Diagnosis
Laryngeal dysplasia arrow palatopharyngeal arch visible over both arytenoid - (branchial arch defect),
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
Figure 46-2. Endoscopic image of the larynx of a horse with grade 4 recurrent laryngeal neuropathy at rest.
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.
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)
(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:
(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.
Figure 46-6. Illustration of the laryngoplasty techniques. Traditional technique:(F) Note position of isthmus of esophagus and its adventitia over the muscular process (*).
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.
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.
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.
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.
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.
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.
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.
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.
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
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. (
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.
Figure 46-17. Endoscopic scissors are being used to remove a granuloma on the medial surface of the left arytenoid cartilage.
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.
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.
Figure 46-24. Endoscopic appearance of epiglottic entrapment showing a thin entrapping membrane where the outline of the epiglottis is still visible.
Figure 46-25. Endoscopic appearance of epiglottic entrapment where the aryepiglottic fold partially entraps the epiglottis and is intermittently relieved by swallowing.
Figure 46-27. Endoscopic appearance of epiglottic entrapment with severe mucosal ulceration, showing exposed granulation tissue and significantly obstructing the view of the larynx.
Figure 46-23. Endoscopic appearance of bilateral mucosal ulcerations on the medial surface of the arytenoid cartilages.
Figure 46-27. Endoscopic appearance of epiglottic entrapment with severe mucosal ulceration, showing exposed granulation tissue and significantly obstructing the view of the laryn
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.)
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.
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.
Figure 46-31. Endoscopic appearance of acute epiglottitis shows the typical edema and thickening of the epiglottis with this condition.
Figure 46-32. Endoscopic appearance of a subepiglottic cyst in a foal; the cyst was resected via laryngotomy.
Diagnosis?
4BAD
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)
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)
Diagnosis
Ventroaxial luxaiton into lumen of rima glottis of corniculate process Barakzai et al 2007
Prevalence 5%
Diagnosis
Axial deviation of aryepiglottic folds ADAF
What is the product injected in case of thick membrane and swollen tissue?
Betamethasone
Dorsal epiglottic abcess
Epiglottic hypoplasia, falccidity, deformity
diagnosis
Epiglottic retroversion
