Surgery of dynamic resp tract disorders Flashcards
What is alar fold collapse and what is the treatment
Where the fold that makes the medial shelf of the false nostril collapses causing loud vibrating noice
Treat via surgical resection of fols
How is respiration in time with locomotor cycle
Expiration when leading leg hits ground in canter
Inspiration when it leaves the ground
CLinical signs of cleft palate
What about in those that have survived to adulthood
Nasal return of food, cough after suckling, aspiration pneumonia
IF it survived; intermitten coughing/dyphagia, noise when exercising due to palate flapping around, associated with epiglottic entrapment
How to manage adults with cleft palate
Feed from floor
Give antibiotics for aspiration pneumonia when needed
What is nasopharyngeal collapse
What horses do we see it in
Neuromuscular dysfunction of walls of pharynx where they come in when horse breathes at exercise
Gives whistling noise
Common in racehorses, fat ponies/cobs
Worse wiht neck/neck flexion e.g in dressage
How does dorsal disaplcement of soft palate present
Marked respi obstruction so gurgle noise and rough respiratory noise
Horse will pull up abruptly and try and swallow
When do we classically see dorsal dispalcement of soft palate
Racehorses at max exertion
Can see in dressage horses associated with head flexion
Fat ponies
What proposed aetiology means we might see DDSP in young racehorses entering training
Due to muscular fatigue of the palate in unfit horsess
How do diagnose dorsal displacement of soft palate
Exercising endoscope because this happens only at exercise
Can make presumptive diagnosis based on jockey report
Proposed causes of DDSP
- Dysfunction of muscles of soft palate
- Fatigue of muscles of soft palate in unfit horses
- URT inflammation/infectino
- Physical lesions that presipose e.g epiglotti entrapment, cysts etc
Conservative treatment strategies for DDSP
Tack changes e.g tongue tie, different nosebands
If young, rest
If unfit, increase fitness
ANti-inflammatories to deal with lwoer rest tract inflammation
Two surgeries that are generally both done for DDSP at once
Tie forward to move position of larynx in relation to palate
Palatoplasty to induce fibrous tissue to tighten up the soft palate
When can we get persistent DDSP
Rare
May see after surgery for epiglottic entrapment
Usually related to predisposing lesion e.g epiglotic entrapment, sub-epiglottic cyst, epiglottitis
What muscle is responsible for abduction of artenoid cartilages laterally and dorsally in exercise
Circoarytenoideus dorsalis
Which are the only two laryngeal cartilages that move
Epiglottis
Arytenoids; abduct to open larynx wide during exercise
WHen do we see maximal arytenoid abduction
After swallowing
Should indcude this during scoping to assess for degree of laryngeal paralysis
What nerve supplies all the intrinsic laryngeal muscles (including cricoarytenoideus dorsalis)
Recurrent laryngeal nerve (branch of vagus)
What is the most common cause of recurrent laryngeal neuropathy
Idiopathis
= axonopathy of left laryngeal nerve
What horses are affected by idiopathic recurrent laryngeal neuropathy
Tall horses
What are some causes of non-idiopathic recurrent laryngeal neuropathy
Perivascular injection of irritant material into neck
Trauma
Systemic disease
Guttural pouch disease
Pathophysiology of recurrent laryngeal neuropathy
Neuropathy of left recurrent laryngeal nerve
Causes atrophy of left CAD muscle so can’t abduct cartilage
So get sucking in of left arytenoid towards midline during inspiration +/- prolapse of left vocal fold
what noises do we get with recurrent laryngeal neuropathy depending on severity
Inspiratory noise (i.e hear when leading leg leaves ground)
If just vocal fold collapsing hear whistling noise
If whole larynx collapses hear roaring noise
Diagnosis of recurrent laryngeal neuropathy
ABnormal inspiratory noise during exercise
May be able to palpate muscular process of arytenod cartilage more prominent on the left due to wastage of CAD
What grade of recurrent laryngeal neuropathy definitely needs a tie back
Grade 4
= complete hemiparesis with no movement
how does RLN grading system wokr
= done during quiet breathing and used to predict likelihood to affect exercise
1 = perfect symmetry and syncrhony
4 = complete hemiparesis with no movement
Treatment options for recurrent laryngeal neuropathy
Vocal cordectomy + ventriculectomy = using laser to cut out vocal fold
–> Done when vocal fold prolapsing but arytenoid cartilage maintains some abduction; generally only in low level work
Prostethic laryngoplasty = tie back; treatment of choice for performance horses or severe cases
Suture muscular process of arytenoid to back of cricoid to mimic action of CAD; keeps left arytenoid in permanently open position
What is arytenoid chondritis and how do we treat
= infection of one/both arytenoid cartilages; get swollen, distorted cartilage which may have granuloma
Rare in UK
Mostly young male TBs
Treat medically with systemic antibiotics and atni-inflammatories long term; can do throat sprays of steroid
Surgery = partial arytenoidectomy to resect some of cartilage
If we palpate a gap between thyroid and cricoid cartilages what does this mean
4th branchial arch defect
Congenital disorder affecting derivatives of emryonic 4th branchial arch
What are the derivatives of embryonic 4th branchial arch
Thyroid cartilage, cricoid, cricpharyngeal muscle (upper oes sphincter), crico-thyroideus mm
What is the most common cause of right sided laryngeal dysfunction
4th branchial arch defect
(can also occur on the left or bilaterally but then other things more common )
Signs with 4th branchial arch defect
Abnormal noise at exercise
Exercise intlerance
Aerophagia since missing upper oesophageal sphincter; can manifest as chronic colic
Diagnostic features of 4th branchial arch defect
Palpate gap b/w thyroid and cricoid
Endoscopy; reduced arytenoid function, rostral displacement of palatopharyngeal arch
Xray: air column in prox oes; aerophagia
What is the most common abnromality on exercising endocopy; causes high pitched inspiratory whistle
Medial deviation of ary-epiglottic folds
Treatment of medial deviation of ary-epiglottic folds
Trim the folds using endoscopic laser to remove excess tissue
Treatment of epiglottic entrapment
Divide membrane iwth hooker knife under standing sedation
How can we tell there is epiglottic entrapment
Can’t see blood vessels and serated edges as seen on normal epiglottis
WHat is epiglottic retroversion
Intermitten sucking back of epiglottis into rima glottis causing intermittent tinspiratory obstruction and gulping noise
Treatment of epiglottic retroversion
Epilottic tie down surgery
Which animals so we see tracheal collapse in
Small breed horses/pnoes
Why do we ge trahceal collapse
Due to instability of dorsal ligament of the trachea usually with chondromalacia of tracheal cartilages
Treatment of tracheal collapse
try to manage medically by treating any LRT issues
No good surgery
What is cobblestone tissue at back of mouth on endoscope mean
Pharyngeal lymphoid hyperplasa
Can be normal to see when young racehorses all brought into training together
Exercising abduction grades for RLN
A = fine
B = vocal fold collapse, gives whistle sound
C = laryngeal arytenoid collapse; gives roaring sound
