Equine upper respiratory tract surgery Flashcards
General comments of URT surgery in the equid?
- Select your cases carefully
- Make sure owner is fully informed and actively involved in decision making
- Many URT surgeries have limited access/ visibility so can be challenging
- Some have potential to make condition worse if you get it wrong!
- Practice evidence-based medicine
- Consider standing laser surgery
- First do no harm!
- Risks associated with general anaesthesia
- Risks associated with airway surgery
Discuss potential cases needing URT surgery?
- Dyspnoea
- URT noise
- Primarily due to poor performance
- URT causes large portion of resistance in URT
- Drop in diameter causes increase in resistance
- Drop in O2 delivery
- If you decrease a tube diameter by half it increases its resistance by times 16
- Other
- Dysphagia
Where can URT sugery be done?
- Conditions of the external nares
- Conditions of the nasal passages and paranasalsinuses
- Conditions of the pharynx and larynx
- Conditions of the guttural pouch
- Tracheal surgery
Anatomy revision of the nares?
External Nares
- Nostril oval at rest then go round at exercise
- Dilate to maximise airflow through system
- Levator nasi mm opens the nares
- Alar fold
- Separates diverticulum (false nostril) from true nostril
- Supports dorsal and lateral nostril
What conditions of the external nares are there?
- Atheromas (cystic structures that sit at top of diverticulum) aka inclusion body cysts
- Redundant alar folds
- Lacerations affecting nostrils
Treatment
- Relatively straightforward
- Main aims are restoration of normal anatomy and good cosmetic effect atheroma
Discuss the importance of reconstructing normal anatomy?
Discuss a wry nose?
- Is surgical intervention necessary/ ethical?
- Reconstruction can be complicated, brutal and expensive depending on degree of deviation
- Most animals with this kind of congenital abnormality will be euthanised
Anatomy revision of the nasal passages?
Nasal Passages
Septum
- Divides right and left nasal passage
Dorsal and ventral conchae
- dorsal, middle, ventral and meatus
- surface area for humidification, temperature regulation, and particulate removal
- Constriction of blood vessels (sympathetic tone)
Meati comes from latin to flow and air flows through them
Discuss nasal passages anatomy?
Ethmoid turbinates (blue arrow)
- caudal aspect
- Ethmoids bleed profusely if damaged
Paranasal sinuses
- Six (or seven) pairs
- Maxillary sinus opens into caudal middle meatus via nasomaxillary opening
- Green arrows naso maxillary aperture
Revision of paranasal sinuses?
- Sphenopalatine, frontal, caudal maxillary, rostral maxillary, dorsal conchal and ventral conchal sinuses (and ethmoidal)
- Septum between caudal and rostral maxillary sinuses (variable location usually 5cm from rostral aspect of facial crest).
- Remember like the alphabet: C (caudal maxillary sinus), D (dorsal maxilally sinus), E (Ethmoid sinus), F (frontal sinus), Ps (sphenopalatine sinsus) ,
Need to know this?
Tooth roots of 4th, 5th and 6th cheek teeth lie within the maxillary sinuses
- infection causes sinusitis
Roots of 3rd cheek tooth forms rostral wall of rostral maxillary sinus
- infection may cause sinusitis
Other structures within maxillary sinuses: nasolacrimal canal and infra-orbital canal
Outline conditions of the nasal passages?
Masses
- Fungal granuloma
- Neoplasia
- Ethmoid hematoma (Expanding blood clot under resp epithelium) See blue arrow
Treatment
- Attempt transendoscopic
Sinus surgery is indicated for?
Sinus surgery indicated for:
- Expansive lesions in paranasalsinus e.g. sinus cyst, neoplasia, ethmoid haematoma, tooth root abscess
- Primary sinusitis (viral or bacterial infection in the paranasal sinusitis)
- Secondary sinusitis (unless we deal with primary cause it won’t go away)
- Severe trauma of facial bones
Discuss conditions of the paranasal sinuses and treatment?
Must identify which sinus is affected
Know anatomical landmarks for each region
Consider endoscopic / laser surgery options first as minimally invasive
Standing sinus surgery has a number of advantages (no anaesthetic risk, less haemorrhage, surprisingly well tolerated by horse)
- Maxillary sinus flap
- Frontal sinus flap
What can be seen here?
TR: sinus cyst
BL: Soft tissue opactiy in the paranasal sinuses
Look at this periapical infection?
Discuss tooth root infection?
- Exodontia commonly necessary for cheek teeth
- Oral extraction if possible
- Tooth repulsion via sinusotomy
- CARE TO GET CORRECT TOOTH, ENTIRE TOOTH AND ONLY THE TOOTH!!!
- Difficult to treat
- high risk of complications
What to do after paranasal sinus surgery?
- Post-operative care important
- Main consideration is resolving infection and establishing drainage
- Systemic antibiotics have some value
- Creating larger drainage ostia during surgery,
- feeding from floor and exercise will all improve drainage
Revise the pharynx?
Pharynx
- Soft palate creates a complete division between nasopharynx and oropharynx which is why horses are obligate nasal breathers
- Nasopharyxvsoropharyx
- Contact w/ sub epiglottictissue during breathing
Any disease of Guttural pouches
- Ostia
- May compress pharynx
- Nerve supply to pharynx may be affected
Revise larynx anatomy?
- Five cartilages
- Epiglottis, cricoid, thyroid, paired arytenoids
Label this?
Discuss conditions of the pharynx and larynx?
- Cleft palate
- DDSP
- Laryngeal hemiplegia
- Arytenoid chondropathy
- Subepiglottic cysts
- Epiglottic entrapment
Discuss conditions of the pharynx and larynx?
CLEFT PALATE
Cleft palate
- nasal reflux of milk / food material and aspiration pneumonia
- Uncommon
- Diagnosed on endoscopy
- Poor prognosis -recurrent infections and poor athletic function
- Surgery -poor success rate ?
- justified
Look at this scope of a cleft palate?
Discuss dorsal displacement of the soft palate treatment?
Dorsal Displacement of the Soft Palate
- Staphylectomy (no longer recommended)
- Myectomy cut the muscles which insert onto the hyoid apparatus (sternothyroid+/-sternohyoid)
- Palatal fibrosis (thermocautery or laser)
- Tie forward (prosthesis to replace thyrohyoidmuscle)– currently most popular and best success rate (80%)
Most have 60% success rate, determining success is difficult
Can have potential to make condition worse
Look at this image of DDSP?
Look at this image of myectomy anatomy?
Look at this anatomy for the tie forward?
Discuss laryngeal hemiplegia?
WHAT IS IT AND TREATMENT
Laryngeal hemiplegia
- Identify and treat underlying cause
- Idiopathic condition
Treatment options:
- Laryngoplasty(tie back)
- Ventriculectomy (Hobday)
- Ventriculocordectomy (similar to hobday+ removal of vocal cords.)
- Arytenoidectomy
- Neuromuscular pedicle graft
How is laryngeal hemiplagia graded?
Grading at rest
- Grade I—normal (symmetric, synchronous)
- Grade II—symmetric, asynchronous
- Grade III—asymmetric, asynchronous
- Grade IV—paralysis
Grading w/ exercise
Grade III
- A—obtain and maintain full abduction
- B—remain asymmetric
- C—become grade IV
Most grade II at rest maintain abduction w/ exercise
Most grade III have some level of obstruction
Ventriculocordectomy
- Experimentally better to reduce noise
- Clinical studies report successful performance outcomes
Look at this laryngoplasty for laryngeal hemiplagia?
Look at this laryngeal hemiplagia post laryngoplasty?
Discuss ventriculectomy?
Discuss arytenoidectomy and neuromuscular pedicle graft?
Arytenoidectomy
- Generally only indicated if other techniques fail Some surgeons 1 st choice
- Arytenoidectomy is more commonly indicated for arytenoidchondropathy
- Progressive inflammatory chondritis, (granulomas and discharging tracts)
- More prevalent in US
- Also occurs in cattle
- Can treat by local excision, partial, sub total or total arytenoidectomy
Neuromuscular pedicle graft
- Try to use other nerves to innervate cricohyoidusdorsalis muscle Low success rate (50-60%)
- Long recovery (6-12 months)
Discuss laryngeal hemiplagia treatment complications?
Laryngeal hemiplegia
- All but Neuro Muscular pedical graft fail to restore normal function or anatomy
- Complications*
- Dysphagia
- Aspiration pneumonia (temporary or permanent)
- 60% of animals with a tie back have a short term cough.
- Avoid excessive abduction Implant failure with laryngoplasty
Discuss arytenoid chondritis?
DIAGNOSIS, CLINICAL SIGNS AND PATHOGENESIS
Diagnosis
Endoscopy (resting)
- Size—compare to other side (tricky if bilateral)
- Mucosa—loss of “ bumps ”,breaks in surface
- Drainage, granulation tissue
Palpation—rounded muscular process
Clinical signs
Vary depending on severity
Poor performance to complete obstruction
Pathogenesis
Unknown-likely secondary to disruption of mucosa w/ ascending infection into cartilage
Discuss arytenoid chonditis treatment?
Treatment
Medical
- Antimicrobial
- Anti-inflammatories
- systemic and local
- Very important acutely
- Often improves significantly
Surgical
- Local excision (via endoscope or laryngotomy)
- Arytenoidectomy—failure of medical management
- Permanent tracheostomy— espif bilateral
Discuss Intralaryngeal granulation tissue treatment?
TREATMENT, PATHOGENESIS AND DIAGNOSIS
Treatment
Excision-endoscopic, laryngotomy
W/ concurrent chondritis
- Excision can make worse
- May require arytenoidectomy
W/ abscessation
- Curettage via laryngotomy
Pathogenesis
- Likely secondary to mucosal ulceration
- +/-chondritisor abscessationof cartilage
- +/-contralateral LH leading to ulceration
Diagnosis
- Endoscopy shows granulation tissue on axial medial aspect of arytenoid
Discuss prognosis of pharynx and larynx surgery?
- Complications –loss of normal anatomy or function
- Ideally –local excision only (laser)
- Partial arytenoidectomy preserves muscular process and articular facet – optimal in terms of airway function
- Prognosis with all surgical treatments –Poor for full athletic function
What can be seen here?
Axial deviation of aryepiglottic folds
- Laser surgery to remove excess tissue
- (Can be done surgically under GA if no laser available)
Discuss subepiglottic cysts?
TREATMENT?
Subepiglottic cysts (congenital or acquired) or granulomas
Treatment by removal
- surgical excision through laryngotomy
- oral removal using Nd:YAGlaser or snare wire
- Good prognosis
Discuss clinical signs and diagnosis of subepiglottic cysts?
Subepiglotticcysts and granulomas
Clinical signs
- Uncommon causes poor performance
- +/-coughing
- +/-dysphagia
Diagnosis
- URT endoscopy
- (may not see)
- Oral examination
- Radiographs
Discuss epiglottic entrapment?
CLINICAL SIGNS, PATHOGENESIS, DIAGNOSIS
Clinical signs
- Poor performance?
- some studies suggest common, one study improved performance
- Respiratory noise
- +/-cough
- +/-nasal discharge
Pathogenesis
- Aryepiglottic fold envelopes epiglottic tip
- Epiglottic hypoplasia??
Diagnosis
- endoscopy
- Lose scalloped border and vascular pattern on dorsal aspect of epiglottis
- +/-mucosal ulceration
- Intermittent entrapment may require exercising endoscopy
- Transect with bistoury, laser or electrosurgery
What are the treatments for epiglottic entrapment?
- Resection of aryepiglotticfolds
- Axial division per os
- Axial division per nasum
- Transendoscopic laser division
All have complications –make sure you cut the right structure!
3 and 4 options have no requirement for anaesthesia
Discuss the anatomy of the guttural pouch?
The guttural pouch
Divided into Medial and lateral compartments
Medial compartment contains:
- internal carotid, cranial sympathetic nerves, cranial cervical ganglion, and cranial nerves IX (glossopharyngeal), X (vagus)and XII (hypoglossal).
- Most mycotic lesions affect the medial compartment
Lateral compartment contains:
- external carotid, maxillary artery and cranial nerve VII (facial nerve).
- More susceptible to injury, either from trauma or iatrogenically
- Stylohyoid bone seperates into medial and lateral compartment .
Discuss conditions of the guttural pouch?
WHAT CONDITIONS CAN YOU GET THERE
- Guttural pouch tympany
- Guttural pouch empyema
- Other masses
- Stylohoid fractures
- Guttural pouch mycosis
Discuss guttural pouch mycosis?
Discuss treatment of guttural pouch mycosis?
Treated by occluding the affecting artery
- Ligation
- Balloon catheter
- Transarterial coil embolization
Ligation has most complications, coil embolization best technique but requires specialist equipment
What can be seen here?
Guttural pouch empyema: Common in horses with strangles
Look at this radiograph?
Discuss guttural pouch surgery?
Guttural pouch surgery
Terrifying!
Access / visualisation is poor
Endoscopic surgery preferred
Tympany
- Fenestration of median septum (unilateral)
- Resection of plica salpingopharangeus
- Salpingopharangeal fistula
Empyema
- Lavage via a Foley catheter
Chondroids
- Basket removal
- Lavage
- Surgery
Discuss the anatomy of the trachea?
- From Larynx to bifurcation (intercostal spaces ICS 5-6)
- C-shaped cartilage rings w/ dorsal muscle/membrane
- Rings connected by annular ligaments
- Vascular and nervous supply in lateral pedicles
- Adjacent structures—esophagus, carotid sheaths, jugular veins
- Pathway for air to and from lung
- Modification of air—temperature, moisture, remove particulates
- Swallowing—food passage through oropharynx, protection from aspiration
- Body temperature regulation
Discuss conditions of the trachea?
Most tracheal surgeries performed to bypass nasal passages, pharynx or larynx
- TRACHEOTOMY (temporary)
- TRACHEOSTOMY (permanent)
Intra-tracheal lesions ie foreign bodies, granulomas, neoplasia
Tracheal collapse
Discuss tracheotomy?
- Performed in the cranial or mid third of neck
- midline dissection to trachea (avoiding neurovascular structures)
- Incision made between and parallel to cartilage rings (DO NOT CUT RINGS)
- Tracheotomy tube (self-retaining silicone or metal J tubes) placed and secured with sutures or bandage
- Aftercare -basic wound management and removing excess discharge
Discuss a tracheostomy?
- Tracheostomy= creation of a permanent stoma
- Normally performed under anaesthesia
- Partial resection of cartilage rings then mucosa sutured to skin
- Wound care and aftercare is significant, and the owner should be advised of this beforehand
- Potential complications include pulmonary infection and drowning
Discuss tracheal surgery?
- With both techniques there is considerable discharge, and the owner should be advised of the cosmetic appearance beforehand
- Should be prepared to do tracheotomy as a life-saving emergency procedure
- Should have kit for this as part of basic anaesthesia / first aid equipment
Look at this metal temporary tracheal tracheostomy?
Discuss conditions of the trachea?
Rarely cause poor performance
Static
- Stenosis 2º to trauma
- External compression— abscess, neoplasia
- Intraluminal granulation tissue—tracheotomy, trauma
Discuss tracheal collapse?
Collapse—dorsal membrane +/- cartilage deformity
- Inspiratory collapse extrathoracic
- Expiratory collapse intrathoracic
Diagnosis –Endoscopy, radiographs, fluoroscopy, ultrasound
Discuss treatment of tracheal conditions?
Treatment
Intraluminal granulation tissue—laser –
Extraluminal compression
- Remove/treat compressing structure
- May need to reconstruct ring
Collapse
- Intra and extra-luminal stenting has been reported
- Success poor
Important points of URT surgery?
- URT surgery can be difficult and associated with complications
- Most common conditions encountered Dental problems, DDSP and laryngeal hemiplegia are common
- First aid / emergency –Recognise guttural pouch mycosis –Know how to do a tracheostomy
- If you go into equine practice, must recognise different conditions on endoscopy even if you have to look up treatment options
Look at these abnormalities in this pre-purchase exam?
what is wrong here?
