Nasal Passages and Paranasal Sinuses in Horses Flashcards
What divides each nostril into dorsal and ventral cavities?
Alar fold
Dorsal blind end 10cm into the nare of a horse
Nasal diverticulum
What are nares supported by?
Alar cartilages
What divides the nasal passages into dorsal, middle, and ventral meatus?
Nasal conchae
Thin scrolls of cartilage and bone
Nasal conchae
The dorsal and ventral meatus are further divided into what compartments?
Rostral conchal bulla
Caudal conchal sinus
Where do most 2* infections d/t dental problems occur and why?
Maxillary sinus d/t molar roots
Which molar root projects to the rostral maxillary sinus?
M1
What sinuses communicate to form the conchofrontal sinus?
Dorsal conchal sinus and frontal sinus
All sinuses indirectly drain through this opening and into the nasal passage
Nasomaxillary opening
Communicates w/ventral conchal sinus over IO canal
Rostral maxillary sinus
Communicates freely w/concofrontal sinus
Caudal maxillary sinus
What is the opening between the caudal maxillary sinus and the concofrontal sinus called?
Fronto-maxillary opening
Communicates with the sphenopalatine
Caudal maxillary sinus
Hemorrhage in submucosa of endoturbinate
Progressive ethmoid hematoma
What age group is an ethmoid hematoma more common in?
~10yo
Are males or females more commonly affected by ethmoid hematomas?
Males
What is the most common cause of ethmoid hematomas?
Idiopathic
Mild, intermittent, unilaeteral epistaxis and facial swelling
Ethmoid hematoma
Dx method useful in patients w/extensife PEH, bilateral disease, or suspected sinus involvement
CT
What is the recurrence rate of an ethmoid hematoma?
40%
How do you treat an ethmoid hematoma?
Intralesional 10% formalin injection q4wk
When can you NOT use intralesional formalin to treat an ethmoid hematoma?
If cribiform plate is damaged (can cause brain damage)
Treatment for large masses in the sinuses
Sinusotomy (bone flap or trephination)
If you surgically remove an ethmoid hematoma (via bone flap), what must you have ready for the horse?
Blood transfusion - will bleed a lot
What is the most common sinus disease?
Sinusitis
What is 2* sinusitis caused by?
Dental disease, sinus cysts, neoplasia
Fluid line on radiographs indicates what disease?
Sinusitis
Unilateral, malodorous nasal discharge and inspissated pus
Empyema of conchal bulla
How do you treat conchal bulla empyema?
Fenestrate bulla, lavage and drain, Nd:YAG laser
Most common expansile mass in the sinuses that leads to distortion of other structures
Paranasal sinus cyst
Causes deviation of the nasal septum
Paranasal sinus cyst
What are uninfected paranasal sinus cysts filled with?
Yellow viscous fluid (like honey)
Are paranasal sinus cysts more common in younger or older adult horses?
Young adults
How do you treat a paranasal sinus cyst?
Sx excision + remove cyst lining
What approach do you use for removal of a paranasal sinus cyst?
Fronto-nasal bone flap
What is the most common neoplasia of the paranasal sinuses? Which sinus is most often affected?
SCC of caudal maxillary sinus
Malodorous breath, swelling, and LN enlargement
SCC
What will you see on CT of a maxillary sinus SCC?
Widespread bone destruction and a well defined mass
What is the prognosis for SCC in the sinuses?
Poor
What type of trephine is most often used?
Galt trephine
Bone flap with limited access in young horses d/t tooth roots
Maxillary bone flap
What are the landmarks for a maxillary bone flap?
Medial canthus of eye along facial crest
Better access to the sinuse than a trephination hole
Bone flap
Bone flap that is more versatile than the maxillary bone flap and provides direct access to conchofrontal and caudal maxillary sinuses
Frontonasal bone flap
How can you gain access to the ventral conchal sinus and rostral maxillary sinus via frontonasal bone flap?
Fenestrate cadodorsal ventral concha
How do you tell the difference between an osteotome and an elevator?
Ostotomes are vivalved
What do you use to close a bone flap?
Skin staples
What is the most important part of paranasal sinus surgery?
Drainage
What post-sinus surgery infections are most common and how do you treat them?
Strep spp. tx w/penicillin and TMS
What type of paranasal sinus surgery results in less bleeding
Standing
