Brachycephalic Airway Syndrome

Question 1

what are the components that make up BOAS

Answer 1

1. stenotic nares
2. elongated soft palate
3. hypoplastic trachea
4. everted laryngeal saccules

Question 2

where are potential sites of obstruction along a brachycephalic airway

Answer 2

nares - stenotic
nasal cavity - compressed turbinates
nasopharynx - nasopharyngeal turbinates
soft palate - elongated/thickened
tongue - macroglossia
pharynx - redundant tissue
larynx - tracheal collapse
trachea - hypoplastic

Question 3

what site (in normal anatomy) is the majority of total airway resistance during inspiration

Answer 3

nasal cavity

should have two pathways of airflow - one turbulent to the brain (to interact with receptors) and one laminar to the lungs

Question 4

do brachycephalics have laminar airflow to the lungs

Answer 4

NO - nasal turbinates are compressed causing poor air movement and increased resistance to flow

requires increased inspiratory effort to move air

Question 5

what is brachycephalic syndrome

Answer 5

abnormal anatomy –> increased airway resistance –> increased negative pressure generated in the lower airways during inspiration –> supraphysiological stress on laryngeal and tracheal cartilage and soft tissues –> tissue edema (swelling), hyperplasia, cartilage weakening

mechanical issues contribute to a functional problem

Question 6

what are the goals of surgical management of BOAS

Answer 6

improving narrowed airways and reducing airway resistance

Question 7

what is the best candidate for BOAS surgery

Answer 7

younger animals

waiting until end stage disease to treat yields less success

Question 8

does BOAS surgery cure the disease

Answer 8

NO - must manage owner expectations that the respiratory difficulty is lifelong and will only improve with surgery, not resolve entirely

Question 9

what components of BOAS can not be treated surgically

Answer 9

1. hypoplastic trachea
2. nasopharyngeal turbinates
3. macroglossia
4. redundant pharyngeal tissue
5. dynamic pharyngeal collapse

Question 10

hypoplastic trachea

Answer 10

-reduced luminal diameter
- overlapping tracheal cartilage
- shortened or absent dorsal tracheal membrane

Question 11

nasopharyngeal turbinates

Answer 11

turbinates extending past the nasal cavity into the nasopharynx

occurs in 20% of brachycephalics

Question 12

redundant pharyngeal tissues

Answer 12

excessive tissue folds contributing to a narrowed airway –> increased turbulence and resistance to air flow

Question 13

dynamic pharyngeal collapse

Answer 13

soft palate pulls upwards during inspiration and collapses the nasopharynx

secondary effect of increased chronic negative airway pressure gradients

Question 14

macroglossia

Answer 14

overly large and thick tongue

increases difficulty during anesthetic recovery

Question 15

what components of BOAS can be addressed surgically

Answer 15

1. stenotic nares
2. elongated soft palate
3. elevated laryngeal saccules

Question 16

what position should BOAS surgery be performed in

Answer 16

sternal or dorsal recumbency

Question 17

what procedure is used to address stenotic nares

Answer 17

rhinoplasty - alar amputation

amputates the medial aspect of the nostril
- must get the entire alar fold all the way back to improve airflow

Question 18

what procedure is used to address elongated soft palate

Answer 18

palatoplasty/staphyloplasty

removes excess soft tissue of the palate that extends caudally past the tip of the epiglottis and into the larynx

use the “inverted U” incision to open airway without taking too much

Question 19

what are everted larygeal saccules

Answer 19

mucosal lining of the lateral ventricles of the larynx (behind the arytenoids) swells and everts
- caused by significant negative airway pressure

FIRST stage of laryngeal collapse

Question 20

what are the stages of laryngeal collapse

Answer 20

1: laryngeal saccule eversion
2: cuneiform process of the arytenoids moves medially
3: corniculate process of the arytenoids moves medially

Question 21

what procedure is used to address everted laryngeal saccules

Answer 21

laryngeal sacculectomy

removing the laryngeal saccules

Question 22

what is laryngeal webbing

Answer 22

complication of laryngeal sacculectomy about 1-4 months after surgery

scar that forms across the laryngeal opening between the arytenoids due to medial contact of “rough edges” after getting cut

Question 23

what medication should be given prior to BOAS surgery

Answer 23

steroids - want to reduce airway edema

IV dexamethasone SP

Question 24

prognosis of BOAS

Answer 24

depends on severity of anatomic malformations

requires long term lifestyle management