Ch 100 Palate Flashcards
Palate
- palate separates the nasal passages, choanae, and nasopharynx from the oral cavity and oropharynx
How may pairs of pharyngeal arches are there in the embryo?
What arches form the mandibular and maxillary prominences?
6 pharyngeal arches
The first arch forms the mandibular and maxillary prominences
Embryology
- secondary palate is formed from bilateral palatal shelves that grow out from the maxillary processes.
- These palatal shelves then elevate rapidly above the tongue and join with each other and the developing nasal septum
What form of epithelium forms in the nasal cavity and the oral cavity?
Nasal - pseudostratified ciliated columnar
Oral - stratified squamous
What bones form the hard palate?
Palatine
Maxillary
Incisive bones
Name the following bones
blood supply
- major palatine artery exits through the major palatine foramen
- major palatine branch of the maxillary division of the trigeminal nerve
- Blood to the soft palate is principally supplied by the minor palatine arteries (which branch off of the maxillary arteries
What is the normal level of extension of the soft palate?
Extends just caudal to last maxillary molar teeth in normal dogs
List the muscles of the soft palate and their function
- Palatinus - shortens the palate rostrocaudally
- Tensor veli palatini - Stretched the soft palate between the pterygoid bones
- Levator veli palatini - Elevates the caudal soft palate
What are the 2 functions of the soft palate during swallowing?
- Stimulation of sensory nerves in the palate are part of the mechanism that triggers swallowing
- Closure of intrapharyngeal opening suring swallowing and vomiting to prevent food entering the nasopharynx and subsequently being aspirated
Palate defects
- Congenital lip and palate defects in cats and dogs can be inherited or are a sequela of intrauterine trauma or stress
- Causes of palate defects acquired after birth include: infections, trauma, neoplasms, and surgical and radiation therapy.
congenital hypoplasia of the soft palate,
- restoration of a palatopharyngeal sphincteric ring and normal swallowing function may not be achieved because of the lack of functional soft palate musculature
What side do unilateral cleft lips most commony form?
left
At what time in foetal development does an insult need to occur to result in a palatal defect?
between day 25-28 in dogs
trauma; stress; corticosteroids, nutritional, hormonal, viral, or toxic
timing of surgery
- Most performed between 3 and 4 months of age.
- Surgery before 2 months of age is challenging
- Postponing surgery until after 5 months of age may result in a wider cleft as the animal grows and compounded management problems, which are not desirable
- prognosis without surgical repair for large defects reported to be guarded because of the risk of aspiration
trauma
- may take several days before the extent of local injury is clearly defined.
List some basic principles of surgical correction of palate defects
- Teeth at the surgical site or those which could damage the repair are removed 6-8 weeks prior to definitive repair
- Laser, electrosurgical and radiosurgical devices not used for haemostasis
- Flap should be at least 1.5x as wide as the defect they are going to cover
- 2-layer closure
- Suture lines preferable not overlying a void
- Injured tissue left to fully declare itself prior to repair
anaesthesia
- Regional analgesia (maxillary, infraorbital, and major palatine nerve blocks)
Repair of Rostral Defects
- congenital defects of the primary palate, attempts to close the lip and most rostral hard palate defects by simple sliding procedures are rarely successful
- Repair is achieved with advancement, rotation, transposition (from labial and buccal mucosa), or overlapping flaps, followed by reconstructive cutaneous surgery to provide symmetry
What is the standard closure technique for a:
- Congenital hard palate defect
- Traumatic hard palate “split” as with highrise syndrome
- Soft palate midline cleft
Congenital hard palate - Overlapping flap
Traumatic highrise syndrome - Medially positioned flap
Soft palate - medially positioned flap
name this flap
Overlapping flap
- There is less tension on the suture line,
- the suture line is not located directly over the defect,
- area of opposing connective tissues is larger, which results in a stronger scar.
- It provides more reliable results
- the major palatine artery must not be transected during flap
- major palatine foramen at the palatine shelf of the maxilla approximately 0.5 to 1.0 cm medial to the maxillary fourth premolar
- Granulation and epithelialization of exposed bone generally are completed in 3 to 4 weeks
name this flap
medially positioned flap
- making relieving incisions approximately 1 to 2 mm away from the maxillary cheek teeth on one or both sides is often necessary unilaterally or bilaterally so that the flaps can be moved medially
- trauma > proper occlusion can be accomplished by approximating displaced bony structures with digital pressure and placing a twisted orthopedic wire between the two maxillary canines and covering it with a self-curing composite resin.
- if the relieving incisions are long and gape, a lateral oronasal defect may result
List options for surgical correction of congenital hypoplasia of the soft palate
- Bilateral tonsillectomy and extension
- Bilateral buccal mucosal flaps (one rotated, one rotated and overlapped)
- Bilateral pharyngeal advancement flaps and one overlapping hard palate flap
How do you repair an oronasal fistula?
Labial-based mucoperiosteal flap
How can you close a large caudal hard palate defect?
split palatal U-flap
List options for large palatal defects
- Removal of teeth 6-8 weeks prior
- Local axial pattern flaps (based on major palatine and infraorbital arteries)
- Distant axial pattern flaps (angularis oris, caudal auricular, superifical temporal etc)
- Tongue flap
- Grafting of auricular cartilage
- Corticocancellous tibial bone
- Myoperitoneal microvascular flaps
- Prostheses (obturator) > Fabrication and placement of a palatal obturator usually requires two anesthetic episodes (metal alloy, nonaqueous elastomeric impression material, or synthetic resin.)
Halitosis is a common complication with palatal obturators. Dogs and cats with palatal obturators should be reexamined under general anesthesia every 6 to 12 months to remove the obturator, flush the nose, clean the edges of the palatal defect, and scale and polish the obturator before it is placed back into position.
complications
wound dehiscence
- result of tension on suture lines because of insufficient flap mobilization before closure
- compromised blood supply of flaps as a result of severe trauma or multiple previous surgeries
- follow-up surgeries should not be attempted before healing of all tissues involved
What % or airway resistance is due to the nose in normal dogs?
80%
BOAS
- primary components: hyperplastic soft palate with mucosal hyperplasia, stenotic nares, hypoplastic trachea, aberrant
nasal turbinates, and macroglossia - eversion of the mucosa of the lateral ventricles occurs secondary to chronic subatmospheric pressure in the airway that is generated to overcome resistance to airflow.
- The turbulent airflow over the mucosa causes edema and swelling.
- Over time, the laryngeal cartilage frame can weaken and the larynx can progressively collapse
What is Poiseuille’s law?
Q = π(pressure difference)(r^4)/8nl
Q - rate of flow
r - radius
n - viscosity of the gas
l - length of airway
Flow is proportional to radius to the fourth power
Pathophysiology
- Stenotic nares and abnormal intranasal turbinate > stertorous breathing due to increased resistance to nasal airflow.
- overlong soft palate projects into the larynx and causes stridor
- causes a fixed-type upper airway obstruction in the majority of brachycephalic dog studies
- increased resistance to airflow is caused largely by a decrease in airway radius as illustrated by Poiseuille’s law
- inspiratory muscles contract for a longer time during each breath cycle in response to increasing upper airway resistance, thus prolonging inspiration
- decreases (PaO2) and increases (PaCO2), stimulates increased respiratory effort when compensation by other mechanisms is inadequate
- Inspiratory and expiratory muscle work generates substantial heat. The work of breathing, combined with hot weather and exercise, often precipitates decompensation in brachycephalic dogs
- funtional dz may contribute > Fibrosis of pharyngeal dilator muscles or Pharyngeal collapse
- are at risk of developing noncardiogenic pulmonary edema
- Presumably, subatmospheric intrapleural pressure required to overcome chronic partial upper airway obstruction in affected dogs predisposed them to hiatal hernia, gastroesophageal reflux, and subsequent esophagitis.
What is the Hering-Breuer reflex?
A stretch reflex mediated by vagal fibres that control the rate and depth of respiration.
Causes a longer contraction of the inspiratory muscles during each breath cycle in response to increased upper airway resistance
What functional disorders may also contribute to BOAS?
Fibrosis of the pharyngeal dilator muscles
Pharyngeal collapse
What % of dogs with BOAS have moderate to severe GI signs?
10-74%
What is the normal tracheal diameter?
20% of thoracic inlet
What should be given before or at induction for upper airway exam?
Anticholinergic to minimise risk of severe bradycardia from vagal discharge during pharyngoscopy
- glycopyrrolate over atropine when needed.
Monitor airway function closely, as thickened secretions and tachycardia can worsen respiratory issues.
Clinical Signs and Diagnosis
- Animals in severe respiratory distress need to be evaluated quickly and intubated if respiratory arrest is imminent
- cold intravenous fluids, sedation with acetylpromazine (0.01 mg/kg IV), oxygen supplementation, and dexamethasone (0.05 to 0.1 mg/kg IV)
- Concurrent cardiac disease has been reported in dogs with overlong soft palates,28 and Bulldogs are particularly prone to congenital pulmonic stenosis.
- radiographs of the neck and thorax to evaluate possible concurrent cardiac disease, aspiration pneumonia, pulmonary edema, and tracheal diameter.
staphalectomy
- proposed level of palate resection, the caudal border of the palatine tonsils
- excessive rostral retraction of the soft palate can make judging the appropriate level of palate resection difficult.
- Clinical experience is therefore often used to determine the appropriate palate length.
- resection is performed with scissors,a carbon dioxide laser, or bipolar sealing device
- caudal pharynx and area surrounding the endotracheal tube must be covered by saline-soaked gauze sponges for protection form laser
folded flap palatoplasty
- by reducing the soft palate’s length and thickness
- removed together with underlying connective tissue and parts of the palatinus and levator veli palatini muscles.
- suture knots will be located more rostral and farther from the pharynx
post op
- Corticosteroids (dexamethasone, 0.05 to 0.1 mg/kg IV
- respiratory rate and effort and arterial hemoglobin oxygen saturation are monitored frequently.
- Food and water are withheld for 12
- postoperative GI signs are aggressively treated with a proton pump inhibitor (omeprazole [0.7 mg/kg PO q24h]), or metoclopramide constant rate infusion [1 to 2 mg/kg/d IV])
dupre and finji
What setting should be used for CO2 laser staphylectomy?
5-6W
Continuous mode
What is the prognosis following soft palate resection?
Good to excellent in 90%
Persistent or recurrent signs should prompt a skull CT and retroflexed nasopharyngeal endoscopy to assess for nasopharyngeal turbinates or progression of laryngeal collapse
complications
- death, most often associated with aspiration pneumonia, failure to recover from anesthesia, or postoperative swelling
- dyspnea and cyanosis
- requiring temporary tracheostomy
- wound breakdown
- failure to improve
- progressive dz
Surgical management of brachycephalic obstructive airway
syndrome: An update on options and outcomes
Mandy L. Wallace 2024
- Relative macroglossia refers to a tongue that is too large for the mouth, which leads to dorsal displacement of the soft palate and further narrowing of the nasopharynx.
- larger esophageal hiatus when compared to nonbrachycephalic
dogs which likely increases incidence of
gastroesophageal reflux, regurgitation, and presence
of sliding hiatal hernias in these dogs - brachycephalic dogs have a significantly
shorter life expectancy compared to non-brachycephalic
dogs with a higher proportion of deaths attributed to
upper respiratory tract disorders
anaesthesia
- brachycephalic dogs were 1.57x more
likely to have an intra-anesthetic complication and 4.33x more likely to have a post-anesthetic complication when compared to non-brachycephalic dogs. A longer duration of anesthesia increased perianesthetic complication risk overall in dogs in this study,
- reducing use of full mu opiates
and having standardized anesthesia and postoperative
protocols have been proposed as methods which may
decrease risk
- without the use of systemic
opiates is the use of a bilateral maxillary nerve block (require less intraop fentanyl and propofol)
- prospective, randomized study, all dogs received a bilateral
maxillary nerve block with half receiving a block of lidocaine alone and the other half receiving a combination
of lidocaine and 0.00198% epinephrine. Blood loss during a cut-and-sew staphylectomy was evaluated in all dogs, with total blood loss being significantly lower for dogs receiving the lidocaine and epinephrine
- preoxygenation for 3 min prior to anesthetic
induction resulted in a significantly longer time to desaturation
- preoperative administration of metoclopramide and
famotidine > may reduce regurge, no change in resp distress or aspiration
surgery
- cut-and-sew or sharp staphylectomy,
carbon dioxide laser,17,18 monopolar electrocautery,18 bipolar
vessel sealing devices,17,19 air plasma devices,20 harmonic
scalpel,21,22 diode laser,18,20,21 and a plasmamediated
bipolar radiofrequency device23
- all of the devices
were found to be effective and generally safe, with minimal
differences noted overall between device used
- one study: dogs undergoing staphylectomy with a bipolar vessel sealing device had a significantly higher rate of perioperative
mortality than. mortality rate prior to discharge from the hospital was 4% > need preospective study to assess if true increase
- FFP: the ventral mucosa of the palate along with the palatinus muscle and part of the levator vili palatini are removed. 55 dogs, no intraoperative complications
were noted; however, 11% of dogs required a temporary
tracheostomy postoperatively and two dogs died
in the perioperative period. In the dogs where follow-up
was obtained, 39/40 (97.5%) had improvement
> palate necrosis was not evident, though the authors noted
that thinning the soft palate too much or leaving the
folded flap too long
> Khoo et al. evaluated
wound healing complications in dogs undergoing
FFP. In this study, 25 dogs underwent FFP and had a
re-evaluation of their soft palate at least 28 days after
surgery. Wound dehiscence was present in 36% of dogs incisional
dehiscence accompanied with caudal retraction of the
soft palate, and in others, a full thickness palate defect
was present. Interestingly, in half of the cases with major
wound dehiscence, no clinical signs were noted
> Miller et al. retrospectively compared
outcomes in 124 dogs undergoing FFP or standard
staphylectomy. In this study, dogs undergoing FFP had
longer surgery and anesthesia durations than dogs undergoing
staphylectomy.
> Grimes et al. comparing
cut-and-sew staphylectomy and FFP in 16 English
Bulldogs used preoperative and 30-day postoperative CT
scans to compare palate length and width. dogs undergoing FFP had longer soft palates postoperatively
than dogs undergoing staphylectomy. No differences
were present in postoperative soft palate width,
oropharyngeal air volume, or nasopharyngeal air volume between the two procedures
- case selection was not limited to dogs
with overly thick palates, which likely benefit more from
this procedure as compared to dogs with thinner palates
which may have an increased risk of palatal defects and
complications after this procedure. (>10mm)
split staphylectomy.
In this procedure, the soft palate is split down midline
using a carbon dioxide laser to the desired length, then at
the thickest point of the palate, the redundant palate tissue
between the mucosal layers is removed using the
laser, allowing for both shortening and thinning of
the palate. Holloway et al. evaluated 75 dogs undergoing
this procedure and found that major complications
occurred in 2.7% of patients with an overall complication
rate of 8.3%.
not possible to make comparisons between this and others
H-pharyngoplasty procedure has the goal of
reducing pharyngeal obstruction through reduction
of redundant pharyngeal mucosa,
Surgical management of brachycephalic obstructive airway
syndrome: An update on options and outcomes
Mandy L. Wallace
stenonic nares
Trader’s technique
- The dorsal
offset rhinoplasty was first described in 2020 by Dickerson
et al. This procedure is suggested to move the alar
cartilage both caudally and dorsally, which theoretically
allows for more openin
- Neither of these procedures was compared to
another technique during the described studies, and comparison
of techniques in clinical patients is an interesting
area of future study.
The ala vestibuloplasty has not been
evaluated in a clinical study on its own
- Franklin
et al. recently compared 3 techniques for correction of
stenotic nares using silicone models. A total of 99 silicone
models were created based on a CT scan of a single
French bulldog’s nose with one of the following procedures
performed on each model: vertical wedge resection,
modified horizontal wedge resection, or ala vestibuloplasty.
CT scans were performed before and after the procedure
with cross-sectional areas measured from the
nares to the nasal vestibules. Increased cross-sectional
areas were found with all three procedures, with ala vestibuloplasty
having a significantly larger cross-sectional
area than the other techniques.36
Surgical management of brachycephalic obstructive airway
syndrome: An update on options and outcomes
Mandy L. Wallace
Everted laryngeal saccules
- reported to be present
in over half of dogs presenting
- some concern that laryngeal sacculectomy
may result in increased postoperative complications > hughs (restrospective, breed diffs)
- undergo spontaneous resolution of eversion after decreasing
airway resistance via performance of other surgical procedures for BOAS. A study by Cantatore et al. evaluating
this concept found that none of the everted saccules spontaneously resolved
> spontaneous resolution
of everted laryngeal saccules is unlikely.
Everted and/or enlarged tonsils
- no studies have specifically looked at
the benefit of tonsillectomy in dogs undergoing > so unknown benefit
- recent studies looking
at tonsillectomy technique in dogs. Turkki et al. evaluated
a tonsillectomy technique whereby the tonsil is
clamped at the base for 20 min then excised using monopolar
electrosurgery > used with some level
of caution and with appropriate postoperative monitoring
for hemorrhage.39
- Two other studies have evaluated use
of a bipolar vessel sealing device for tonsillectomy > showed 1–2 mm of
coagulation necrosis, faster, less bleed
Aberrant nasal turbinates
- common in brachycephalic
dogs with the majority of dogs
- LATE considered to be safe with the main complication being
intraoperative hemorrhage which is usually self-limiting.
In one study, regrowth of the aberrant turbinates
6 months after the initial removal leading to potential
reobstruction and need for a second removal occurred in
15.8% of dogs
- Liu et al., a BOAS index and BOAS
functional grades were obtained from brachycephalic
dogs prior to and 2–6 months after conventional BOAS
surgery. Dogs with a BOAS index >50% and a BOAS
functional grade of 2–3 at the postoperative follow-up
were considered candidates for the LATE procedure.
Using those criteria, 29/57 dogs were candidates for
LATE
- significant
improvement in their BOAS index when
compared pre- and post-procedure.
Surgical management of brachycephalic obstructive airway
syndrome: An update on options and outcomes
Mandy L. Wallace
POSTOPERATIVE
MANAGEMENT AFTER SURGICAL
MANAGEMENT OF BOAS
- Careful monitoring and controlled recovery from anesthesia
are imperative to limit the risks
- Lindsay
et al. evaluating postoperative respiratory complications
in 248 dogs undergoing surgery for BOAS,
respiratory complications were noted in 23.4%, with an
overall mortality rate of 2.4%. Risk factors for developing
a complication included older age, presence of airway
pathology that was not a primary component of BOAS
(such as laryngeal collapse or tracheal collapse), and presenting
in an emergent fashion for surgery > highlights the importance of early surgical intervention
for dogs with BOAS while dogs are younger
- Fenner et al.
evaluated postoperative regurgitation in dogs undergoing
surgery for BOAS and found that younger dogs were
more likely to experience regurgitation in the postoperative
period, with the odds of postoperative regurgitation
reduced 28.8% for every one-year increase in age. Dogs
with a history of regurgitation prior to surgery were also
more likely to experience regurgitation postoperatively
- Ree et al. looking at short-term complications after BOAS
surgery found a major complication rate of 7%,
- filipas need
for tracheostomy postoperatively and were increasing
BOAS grade and the presence of pre- and postoperative
aspiration pneumonia.
- same day discharge from the hospital for dogs
undergoing BOAS surgery. In a retrospective study by
Camarasa et al. Dogs that underwent standard
recovery had a significantly higher rate of complications
(28%) compared to dogs undergoing owner-assisted
recovery (2%).
- Nebulized epinephrine has also been evaluated as a
way to decrease postoperative upper airway obstruction
in dogs undergoing BOAS surgery. A significant
decrease in BOAS index was noted pre- and postoperatively
in this population of dogs. All dogs received
this treatment; therefore, comparisons could not be made
- Fenner et al. evaluated 0.5 mg epinephrine in
4.5 mL of saline nebulized to patients that were
experiencing stertor or dyspnea after surgery. In this
study, they found that only 4/90 dogs experienced agitation
after nebulization, and there were no significant differences
in heart rate or respiratory rate 60 min after
nebulization. There was no control group
- high-flow oxygen therapy. This
modality uses a specific nasal cannula system that allows
for very high oxygen flow rates
- nasotracheal intubation,
which bypasses the upper airway obstruction that can
occur postoperatively in brachycephalic dogs. With this
technique, a 5–10 French tube is inserted through the
naris > 36 dogs undergoing BOAS surgery, nasotracheal tubes
were placed in 20 of the dogs, with the remaining dogs
receiving oxygen supplementation in another way or no
oxygen supplementation at all. Complication rates were
similar between groups; however, no dogs with a nasotracheal
tube experienced respiratory distress
- Worth et al. evaluating risk factors for dogs that
required a postoperative temporary tracheostomy identified
a 30% increased odds of needing a temporary tracheostomy
for each 1 year increase in age, further
highlighting the importance of early surgical intervention
in brachycephalic dogs.54
- Placement of a temporary tracheostomy
tube in these patients often results in positive
outcomes, with 40/42 dogs surviving to discharge in a
study by Stordalen et al. with no long-term complications
- Grimes et al. found that brachycephalic
dogs were significantly more likely to require revision
surgery after having a permanent tracheostomy as
compared to non-brachycephalic dogs
- Gobbetti et al. evaluated long-term outcome after permanent
tracheostomy specifically in brachycephalic dogs
with severe laryngeal collapse. Of 15 dogs in the study,
eight died secondary to a major complication, with major
complications occurring in 80% of dogs. Long-term survival
of over 5 years after surgery with a good quality of in 5/15
post -op complications, mortality risk factors
major comp 7%
resp compl 15-23.4
mortality 2.4 - 4% (0-10%)
temporary tracheostomy 5- 8% (0-11%)
risk factors: older, coallapse, emregent presentation, worse BOAS, post-op trach, post-op pneumonia, pre-op regurge > post op regurge,
Factors for temporary tracheostomy postoperatively
age
postoperative aspiration pneumonia,
concurrent airway pathology,
emergent presentation prior to surgery
increased surgical duration
Surgical management of brachycephalic obstructive airway
syndrome: An update on options and outcomes
Mandy L. Wallace
OUTCOME IN DOGS AFTER
SURGICAL MANAGEMENT OF BOAS
- not all abnormalities associated with
BOAS can be addressed surgically, such as hypoplastic
trachea or macroglossia, or may not completely improve
with surgical management.
- Seneviratne et al. evaluating outcome at 6 weeks after
surgery for BOAS, it was noted that almost 71% of dogs
showed improvement in respiratory signs
- Liu et al. evaluated dogs
1–6 months after surgery and found that the median
BOAS index decreased after surgery, though the
median postoperative BOAS index was still in the clinically
affected range. youong age, collapse negtive
> modified multilevel
surgery, consisting of an ala-vestibuloplasty, modified
folded flap palatoplasty, removal of everted laryngeal saccules
(when indicated), removal of everted tonsils (when
indicated), and a partial cuneiformectomy in dogs with
grade 2 or 3 laryngeal collapse, was found to be associated
with a positive outcome more often than traditional
multilevel surgery,
Doyle et al. compared dogs that had undergone
anesthesia before and after BOAS surgery and compared
the complication rates at each procedure. Dogs that had
undergone BOAS surgery had 79% decreased odds of having
a post-anesthetic complication at subsequent anesthetic
event
The study found that dogs
with BOAS had a significantly higher reduction in the
dorsoventral dimensions of the pharynx during respiration
when compared to the control dogs. Unfortunately,
no significant improvement was noted in this measurement
after surgery in a cohort of the dogs with BOAS,
though if more dogs had been evaluated a difference may
have been seen.59 Interestingly, nasopharyngeal collapse
with a pharyngeal diameter change of greater than 50%
has been documented using fluoroscopy in a small percentage
of normal Beagles without evidence of cardiopulmonary
disease indicating that the visualization of this
collapse on imaging modalities may not correlate to clinical
disease
Mayhew et al. where dogs were compared
pre- and postoperatively via a standardized owner
questionnaire and via endoscopy to evaluate for gastroesophageal
reflux and presence and severity of a sliding
hiatal hernia. Owners perceived improvement postoperatively
in regurgitation after eating and in regurgitation
during increased activity or exercise. Unfortunately, no
differences were noted in endoscopic evaluation of gastroesophageal
reflux or incidence and severity of sliding
hiatal hernia in these dogs after surgery.61 Poncet et al.
evaluated owner perception of improvement in gastrointestinal
signs after BOAS surgery in dogs that were also
receiving medical management for gastrointestinal disorders
and found that owners noted excellent or good
improvement in gastrointestinal disorders in over 90% of
dogs
Risk factors for complicated perioperative recovery in dogs
undergoing staphylectomy or folded flap palatoplasty:
Seventy-six cases (2018–2022)
Agnieszka B. Fracka 2024
Study design: Retrospective study.
Animals: Seventy-six client-owned dogs
identified four risk factors for complicated recovery. These
include surgery type (p = .0002), age (p = .0113), laryngeal collapse grade >2
(p < .0001) and length of general anesthesia (p = .0051).
Postoperative complications occurred in 30 out of 76 dogs
(39%), of which 16 dogs (53%) experienced major complications
and 14 dogs (47%) experienced minor complications.
Of the 16 dogs with major complications, all were
either requiring prolonged oxygen treatment and or
needed a tracheostomy and or died during recovery.
Dexmedetomidine
CRI was required due to anxiety with or without respiratory
distress in 20 dogs (26%) postoperatively,
A total of 12 of the surgical cases
(16%) regurgitated after surgery
A temporary tracheostomy
was performed in six of 76 dogs (8%)
Three dogs (4%) died or were
euthanized prior to discharge from the hospital.
staphylectomy was associated with an
increased risk of complicated surgery as compared to
FFP. We do however advise caution when interpreting
the effect size of surgery type
Comparison of mortality of brachycephalic dogs undergoing
partial staphylectomy using conventional incisional, carbon
dioxide laser, or bipolar vessel sealing device
Sarah A. Jones 2024
Retrospective multicenter cohort study.
Animals: A total of 606 client-owned English bulldogs, French bulldogs, and pugs.
overall mortality rate was 24/606 (4.0%). Of those 24 dogs,
staphylectomy was performed with BVSD technique in 13 cases, with CO2 laser
in nine, and using conventional incisional technique in two.
Nine dogs were
graded II or III laryngeal collapse, 14 were graded I,
Conclusion: The use of BVSD and grade of laryngeal collapse were associated
with a higher risk of perioperative mortality. No difference between cuting and CO2 laser.
histopathology of the soft palate revealed higher damage
scores for the CO2 laser group at day 0, no differences
were detected at days 3, 7, and 14.18 Another retrospective
study evaluating risk factors for temporary tracheostomy
following corrective surgery for BOAS in 122 dogs
also demonstrated no statistical difference between
these two techniques.13
prospective needed
Evaluation of the addition of adrenaline in a bilateral
maxillary nerve block to reduce hemorrhage in dogs
undergoing sharp staphylectomy for brachycephalic
obstructive airway syndrome. A prospective,
randomized study
Phillipa J. Williams 2024
Study design: Prospective, randomized, double-blinded controlled study.
Sample population: A total of 32 client owned
This study demonstrated that the use of adrenaline in a bilateral
maxillary nerve block results in significantly lower intraoperative hemorrhage
during cut and sew sharp staphylectomy and appeared safe to use.
Complications and outcome following staphylectomy and
folded flap palatoplasty in dogs with brachycephalic
obstructive airway syndrome
Annellie K. Miller 2024
Retrospective study.
Sample population: Client-owned dogs (n = 124).
FFP dogs
without concurrent non-airway procedures were associated with longer
duration of surgery (p = .02; n = 63; S, median = 51 min [34–85]; FFP,
median = 75 min [56.25–94.5]) and anesthesia (p = .02; n = 63; S,
median = 80 min [66–125]; FFP, median = 111 min [91–140.8]). Neither
soft palate surgery was associated with the occurrence of anesthetic complications
(p = .30; 99/120; S, 49; FFP, 50), postoperative regurgitation
(p = .18; 27/124; S, 17; FFP, 10), or with hospitalization duration
Although FFP took longer, no other clinically significant
differences were appreciated between S and FFP procedure The results of this study indicated that S and FFP surgeries
had similar anesthetic, minor, and major complications,
as well as similar hospitalization duration
the FFP has been reported to involve more
tissue manipulation and longer surgical times
A retrospective observational cohort study on the postoperative respiratory complications and their risk factors in brachycephalic dogs undergoing BOAS surgery: 199 cases (2019-2021)
M. C. Filipas1, L. Owen and C. Adami 2024
Four postoperative respiratory complications were observed: hypoxaemia (n=10/199; 5%), dyspnoea requiring tracheal re-intubation (n=13/199, 7%), dyspnoea requiring tracheostomy (n=10/199, 5%) and aspiration pneumonia (n=12/199, 6%).
Risk factors for tracheostomy were preoperative and postoperative aspiration pneumonia and increasing brachycephalic obstructive airway syndrome grade
Nebulised adrenaline in the post-operative
management of brachycephalic obstructive airway
syndrome in dogs: short-term outcomes in 90
cases (2014–2020)
JVH Fenner, CC Henderson & JL Demetriou 2023
NZVJ
retrspective
Agitation following nebulisation with adrenaline was uncommon, with 86/90
(96%) dogs remaining calm,
A temporary tracheostomy tube
was placed in 13 (14.4%) dogs
Nebulisation with adrenaline is feasible, results in minimal increases in
respiratory rate and heart rate and is associated with agitation in only a small number of dogs.
Adrenaline’s action on α-adrenergic receptors
leads to decreased vasodilation. It is hypothesised that
adrenaline acts directly on the mucosa of the upper
airways to cause vasoconstriction of the vessels,
thereby reducing oedema
dont comment on efficacy (complicatinos rates were the same )
Wound healing complications following folded flap palatoplasty
in brachycephalic dogs
T-X Khoo 2022
AVJ
Prospective study of 25 dogs
- monopolar 8/13 (61.5%) vs scissors 1/11 (9.1%)
Wound healing complications occurred in nine dogs
(36%). Minor and major wound complications were diagnosed at
a median of 36 days (1.5–51 days) post-operatively. Eight dogs
had major wound complications, four of which showed no associated
clinical signs. Two patterns of major wound complications
were observed: incisional dehiscence (ID) with caudal retraction
of the soft palate mucosa and development of a full-thickness
defect (FTD) in the centre of the soft palate
Clinical improvements in respiratory function after
FFP has been established both by subjective outcomes assessment
and, more objectively, by whole-body barometric plethysmography.
1
influence of the generation of a random, single pedicle mucosal
advancement flap on the perfusion of the remaining tissues is
unknown.
direct injury, thrombosis or stasis of perfusion
through the subepithelial plexus, or its suppliers in the lamina
propria, has the potential to result in ischaemia and is a plausible
pathomechanism for FTD, particularly when dissection is continued
to the deep margin of the dorsal soft palate mucosa
incision into the lateral and rostral tissues of the soft palate during
FFP means that vascular supply to the advanced flap is likely reliant
on anastomoses to the vasculature of the dorsal soft palate. A failure
of adequate perfusion of the flap, potentially from injury to the dorsal
vascular supply during dissection, may contribute to the development
of ID.
Brachycephalic airway syndrome: management of post-operative
respiratory complications in 248 dogs
B Lindsay 2020
AVJ 2020
Fifty-eight dogs
(23.4%) had complications which included: dyspnoea managed
with supplemental oxygen alone (7.3%, n = 18), dyspnoea requiring
anaesthesia and re-intubation (8.9%, n = 22), dyspnoea necessitating
treatment with a temporary tracheostomy (8.9%, n = 22),
aspiration pneumonia (4%, n = 10), and respiratory or cardiac
arrest (2.4%, n = 6). Five of the 22 dogs requiring anaesthesia and
re-intubation deteriorated 12 or more hours after post-surgical
anaesthetic recovery. The overall mortality rate in this study was
2.4% (n = 6).
data show the importance of close monitoring
for a minimum of 24 h following surgery by an experienced veterinarian
or veterinary technician.
22 dogs requiring re-anaesthetising and re-intubation,
five of these deteriorated more than 12 h after surgery (which in most
cases was the night after surgery). Of the six dogs who developed
respiratory or cardiac arrest, three of these dogs arrested the night
after surgery or the following day.
Successful recovery
following temporary tracheostomy tube placement was made in
19/21 cases
Nasopharyngeal collapse can be identified on radiography in
healthymale Beagle dogswithout cardiopulmonary diseases
Hyemin Na 2022
VRU
The study sample included 42 Beagle dogs
This study revealed that change in nasopharyngeal
lumen over 50% can be identified in Beagle dogswithout cardiopulmonary diseases
and may be over-diagnosed as partial pharyngeal collapse. Further studies for
comparing change in nasopharyngeal lumen between clinically normal dogs and dogs
with respiratory signs are warranted.
Owner-assisted recovery and early discharge after surgical treatment in dogs with brachycephalic obstructive airway syndrome
J. J. Camarasa 2023
Sixty-three dogs met the inclusion criteria for the study. Forty-two dogs underwent owner-assisted recovery and 21 dogs standard recovery. No statistical difference was found between groups in age, breed, gender, severity of respiratory or gastrointestinal clinical signs and surgical techniques employed. The incidence of postoperative complications was higher in dogs that received standard recovery (28%) compared to dogs recovered with the owners (2%). None of the dogs recovered with the owners and discharged the same day required veterinary assistance after discharge from the hospital.
that the percentage of dogs with severe laryngeal collapse was
higher in dogs that underwent standard recovery. However, the
stage of laryngeal collapse as a prognostic indicator in BOAS surgery
is controversial
Effect of conventional multilevel brachycephalic
obstructive airway syndrome surgery on clinical and
videofluoroscopic evidence of hiatal herniation and
gastroesophageal reflux in dogs
Philipp D. Mayhew 2022
Prospective clinical trial.
Animals: Sixteen client-owned dogs
Owners of dogs treated with CMS perceived an improvement in
clinical signs of SHH and GER that was not confirmed by VFSS studies.
Clinical significance: Conventional multilevel surgery in dogs with BOAS
does not appear to consistently resolve SHH and GER, although clinical signs
may improve.
study by Poncet,11 a very similar percentage of dogs
(approximately 80%) showed an improvement in their
gastrointestinal clinical signs and in 10 dogs in that study
that underwent endoscopic reevaluation,
the response was variable and approximately 25%-30%
appear to be “nonresponders.”
The inferiority
of VFSS compared to 24 h ambulatory pH monitoring or
high-resolution manometry has been reported in human
medicine
Outcomes and prognostic factors of surgical treatments for
brachycephalic obstructive airway syndrome in 3 breeds
Nai-Chieh Liu 2017
Study Design: Prospective clinical study.
Noninvasive whole-body barometric plethysmography (WBBP) was used
to assess respiratory function before, 1 month and 6 months after upper airway corrective
surgery
median BOAS indices decreased after surgery (from 76% to 63%, although dogs with indices in this range would still be considered clinically
affected.
age, collapse and surgery associated with prognosis
suggests modified multilevel surgery (MMS) may have a better outcome than
traditional multilevel surgery (TMS) (
Younger age, normal body condition, presence of laryngeal collapse, and treatment with TMS were negative prognostic factor
Based on a pilot study, more
severely affected French bulldogs had a poorer response to
traditional multilevel BOAS surgery (ie, postoperative
BOAS indices were still considered clinically affected) when
compared to moderately affected French bulldogs
respiratory functions remained compromised in 60% of dogs
resection of the dorso-medial and caudal portion
of the alar fold creates a wider nasal vestibule and releases
both the external and the inner stenosis36
MMS
- modified rhinoplasty technique combining a Trader’s
alaplasty34 and nasal vestibuloplasty
- FFP
- bilateral ventriculectomy
- partial cuneiformectomy11for dogs with Grade II or
III laryngeal collapse;
- partial tonsillectomy in dogs with
extruded tonsils (
Severity of nasopharyngeal collapse before and after
corrective upper airway surgery in brachycephalic dogs
Dana L. Clarke
Dogs were evaluated with fluoroscopy awake and standing
corrective upper airway surgery
(alaplasty, staphylectomy, sacculectomy, tonsillectomy) was performed. A
cohort (n = 11) of the surgically treated brachycephalic dogs had fluoroscopy
repeated a minimum of 6 weeks after surgery.
Surgery did not improve the reduction
in dorsoventral diameter of the nasopharynx during respiration in brachycephalic
dogs (n = 11) postoperatively (p = .0505).
The lack of significant postoperative
improvement may represent a type II error, a failure to adequately address
anatomical abnormalities that increase resistance to airflow, or inadequate
upper airway dilator muscle function in some brachycephalic dogs.
Comparison of harmonic shears, diode laser, and scissor cutting and
suturing for caudal palatoplasty in dogs with brachycephalic obstructive
airway syndrome
A. Conte a,*,
VJ
The harmonic shears resulted in the shortest surgical times (HSS 46 s, DLS 300 s, SIS 360 s; P < 0.001). There
was a difference in the intraoperative haemorrhage among the three techniques; intraoperative haemorrhage did
not occur in HSS and DLS groups. HSS was associated with more frequent damage involving the connective tissue
(P = 0.001), muscle (P = 0.038), salivary gland tissue (P < 0.001), but less oedema was observed (P < 0.001).
HSS was the fastest of the techniques evaluated for caudal elongated soft palate resection, resulting in less tissue
oedema, and no intra-operative haemorrhage. These characteristics might result in reduced postoperative
swelling and airway obstruction compared to other techniques.
Evaluation of temporary palatopexy to manage brachycephalic obstructive airway syndrome in dogs in respiratory distress
J. A. Sun 2021
prospective pilot study, seven client-owned brachycephalic dogs
Six out of seven dogs were successfully extubated less than 2 hours post palatopexy and survived to discharge. One dog failed extubation secondary to worsening lower airway disease and laryngeal collapse.
one to three
vertical mattress sutures placed using 2-0 or 3-0 poliglecaprone 25
(Monocryl: Ethicon), tacking the caudal free edge of the soft palate
rostrally to the junction of the hard and soft palate
procedure may be less successful in addressing a BOAS crisis
if other abnormalities or lower airway disease are significant
contributors. This was demonstrated in the one dog in this pilot
study who required emergent re-intubation, likely due to a combination
of pneumonia and laryngeal collapse
Palatopexy may also be useful as a temporary measure to
bridge the time between crisis and definitive BOAS surgery. This
could allow time for any inflammation and oedema to subside
without having to keep patients in severe respiratory distress
intubated or tracheostomized, as
Nebulization of epinephrine to reduce the severity
of brachycephalic obstructive airway syndrome in dogs
Phil H. Franklin 2021
Prospective clinical study.
Sample population: Thirty-one client-owned
Whole body barometric plethysmography was used to determine
BOAS severity (BOAS index; 0%–100%) prior to and after nebulization with
0.05 mg/kg epinephrine diluted in 0.9% saline preoperatively
Five dogs were excluded because they did not tolerate nebulization,
and postoperative data were available for 13 dogs
Nebulized epinephrine reduced the BOAS index of dogs in this
study. This effect was clinically significant in preoperative dogs with a BOAS
index >70% and in dogs recovering from surgery.
Anesthetic risk during subsequent anesthetic events
in brachycephalic dogs that have undergone corrective
airway surgery: 45 cases (2007-2019)
doyle 2020
The odds of having complications during the postanesthetic period following
subsequent anesthetic events were decreased by 79% in dogs having
previous surgical intervention to correct clinical signs of brachycephalic airway
syndrome.
Previous corrective upper airway surgery decreased odds of postanesthetic
complications in brachycephalic dogs that underwent subsequent anesthetic
events.
Postoperative regurgitation and respiratory complications
in brachycephalic dogs undergoing airway surgery
before and after implementation of a standardized
perianesthetic protocol
Renata S. Costa 2020
84 client-owned dogs
preoperative administration of
metoclopramide and famotidine, restrictive use of opioids, and recovery
of patients in the intensive care unit
undergoing
anesthesia for airway surgery before (group A) and after (group B) protocol
implementation were reviewed
The proportion of dogs with postoperative regurgitation in group B (4/44
[9%]) was significantly lower than that in group A (14/40 [35%]).
Rates of
development of postoperative pneumonia and respiratory distress did not
differ between groups. A history of regurgitation was associated with development
of postoperative regurgitation.
The impact of tongue dimension on air volume
in brachycephalic dogs
Brittani A. Jones 2020
Sixteen brachycephalic dogs and 12 mesaticephalic dogs.
A relative macroglossia was detected in brachycephalic dogs along
with reduced air volume in the upper airway. Tongues of brachycephalic dogs were
denser than those of mesaticephalic dogs.
Clinical significance: The relative macroglossia in brachycephalic breeds may
contribute to upper airway obstruction.
Postoperative regurgitation in dogs after upper airway surgery to
treat brachycephalic obstructive airway syndrome: 258 cases
(2013-2017)
Joy V. H. Fenner 2020
Corrective surgery for BOAS was associated with a marked incidence
of postoperative regurgitation. Younger dogs and those with a history of regurgitation
were predisposed to postoperative regurgitation.
Use of a barrier membrane to repair congenital hard palate defects and to close oronasal fistulae remaining after cleft palate repair: seven dogs (2019–2022)
Ana C. Castejón-González 2024
hard palate defect was closed with medially positioned flaps (Von Langenbeck technique) or pedicle flaps (2-flap palatoplasty) and a membrane composed of autologous auricular cartilage from the pinna or allogenous fascia lata underlying the mucoperiosteal flaps.
Resolution of clinical signs occurred in all cases. Complete success (ie, complete closure of the palate defect and absence of clinical signs) was achieved in 5 dogs
The size of the soft tissue defect of the hard palate was classified as mild if it was < 25% of the width of the palate at the same location, moderate if the relative width was between 25% and 50%, or severe if it was > 50%.
The chance of successful closure of an ONF decreases with the number of failed surgeries performed in people and dogs, and a small ONF may persist despite multiple surgical attempts at closure.
Common areas of failure after CFP repair are rostrally near the incisive papilla and caudally at the transition between the hard and soft palate.3,6
Surgical closure of cleft palate defects in dogs
using a modification of the traditional
von Langenbeck technique: 12 cases (2015–2022)
Pavletic 2023
Successful closure of the cleft (hard and soft) palate defects was achieved in all 12 dogs in a single surgical procedure. A small residual opening was noted at the level of the incisive papilla in each dog; this was of no clinical consequence in this report
Successful execution requires the complete elevation of each flap, which facilitates their tension-free advancement over the palatal cleft. Vertical mattress sutures evert the flap margins, allowing for direct collagen surface contact for proper healing. Placement of sutures in the rugal folds increases the tissue purchase to reduce the risk of suture cut-out. Fine interrupted sutures, placed between the vertical mattress sutures, maintains the proper alignment of the incisional margins. The author waits a minimum of 5 months before closing cleft palate defects,
Computed tomographic findings in dogs has demonstrated variable abnormalities in individual dogs, including the following: abnormal development of the incisive and maxillary bones, absent or poorly developed nasal septum, hypoplastic nasal turbinates, vomer abnormalities, incomplete cribiform plate, abnormal tympanic bullae, anomalous frontal sinuses, otitis media, anomalous frontal sinuses, and displaced ventricles or ventriculomegaly
CT may not essential to cleft palate repair in many cases, it may be useful nonetheless in planning a problematic closure and detecting other anomalies
It has been suggested that waiting until 5 months of age runs the risk of the defect enlarging.29 This, however, is contrary to the author’s clinical experience. The cleft either remains proportional to the lateral palatal donor areas or proportionately decreases in width when compared to the initial assessment of the defect at birth. Another study38 suggested that oronasal fistula formation may be greater in dogs over 8 months of age. This was not recognized in this current case study.
Surgical treatment for cleft palate in dogs yields
excellent outcomes despite high rates of oronasal
fistula formation: a narrative review
Ana C. Castejón-González 2023
Surgical treatment has good to excellent outcomes when the procedure is carefully planned and appropriately
executed despite the high rates of postoperative oronasal fistula reported
bilateral overlapping flaps covered by labial/
buccal advancement flaps
The rate of ONF may reach 50% to 100% after the initial CP repair.
Risk factors for developing ONF in
dogs are previous surgical attempts and CP repair
after 8 months of age
An ONF immediately caudal to the incisive papilla
may not show as many clinical signs a
Angularis oris axial pattern flaps, large buccalbased
advancement flaps, and use of auricular cartilage
grafts and fascia lata membrane
1 study, 33% of dogs had
more than 1 surgery performed to repair the ONF
Findings indicated that incidence of clinical GER during the postoperative
period was not lower for dogs that received preoperative prophylactic administration
of metoclopramide and maropitant, compared with incidence
dogs that did not receive the prophylactic treatment. Further research is
required into alternative measures to prevent postoperative clinical GER in
dogs.
we did not detect an association between
clinical GER and dexmedetomidine administered as an anesthetic premedication or as a postoperative bolus injection
Hard palate defect repair by using haired angularis oris
axial pattern flaps in dogs
Nima Nakahara 2020
Anatomical cadaver study and short case series.
Animals: One cadaver and three dogs with neoplasia of caudal hard palate
Anatomical studies provide evidence that the HAOF can be used
to reconstruct caudal and central hard palate defects extending to the maxillary
canine teeth. Its clinical use led to successful closure of such defects in
three dogs.
In conclusion, the HAOF may be an alternative to the
buccal mucosal or hard palate flaps that have been previously
reported.
Validation of exercise testing and laryngeal auscultation for
grading brachycephalic obstructive airway syndrome in pugs,
French bulldogs, and English bulldogs by using whole-body
barometric plethysmography
Julia Riggs 2019
Whole-body
barometric plethysmography was used as a comparative, objective measure of
disease severity
The sensitivity of clinical examination for BOAS diagnosis was 56.7%
pre-ET, 70% after a 5-minute walk test, and 93.3% after a 3-minute trot test. The
sensitivity of laryngeal stridor as a predictor of laryngeal collapse was improved
after exercise (70%) compared with before exercise (60%). Specificity of laryngeal
stridor for laryngeal collapse was 100% (pre-exercise and postexercise).
simple and inexpensive diagnostic
test correlates well with objective plethysmography data,
and widespread application of the functional grading scheme
described could help to standardize the way BOAS dogs are
assessed and improve the accuracy and transferability of
clinical records.
Tarricone 2019 – brachycephalic risk (BRisk) score for prediction of risk of complications
- BRisk developed from admission data → negative correlation with outcome
- score >3 → 9.1x more likely to have negative outcome
- risk factors: breed (English/French bulldog), hx of previous airway sx, BCS <2.5 or >3.5
admission status (stertor at rest, requirement for O2,
sedation or intubation)
additional planned procedures, rectal temperature (higher temp protective)
