Alright Hound community, let’s dive into something crucial for our brachycephalic patients. We know you’re all about providing the best care, and that means staying sharp on complex conditions. That’s why we’re thrilled to share this in-depth look at Canine Brachycephalic Obstructive Airway Syndrome (BOAS), courtesy of one of our valued sponsors.

At Hound, we believe in empowering veterinary professionals with the knowledge they need to make informed decisions. BOAS is a multifaceted challenge, and understanding its intricacies is essential for effective diagnosis and treatment. This detailed breakdown covers everything from primary and secondary conditions to surgical interventions and prognostic factors.

This post isn’t just a collection of medical terms; it’s a practical resource designed to help you improve the quality of life for your brachycephalic patients. We’re grateful to VetGuardian for sharing their expertise and helping us bring this valuable information to you. So, grab your coffee, settle in, and let’s get ready to deepen our understanding of BOAS. 

Primary and Secondary Conditions

Primary conditions include elongated soft palate (62-100% incidence), hypoplastic trachea (11-46%), nasopharyngeal stenosis (nasal turbinate abnormalities, 20-100%), and stenotic nares (17-94%). Secondary conditions include everted laryngeal saccules (39-87%), everted tonsils (amygdalitis, 5-56%), and laryngeal collapse (-53%).

Anatomical Characteristics of Brachycephalics

Brachycephalics have a wide skull and a shortened length, smaller glottic index, more elliptical larynx shape, smaller nasopharynx, thickened bullae, abnormal shape/quantity of sinuses, longer, thicker and more caudally located soft palate, macroglossia, and nasal septum deviation, bronchial abnormalities, decreased buccal opening, epiglottic cysts, excessive aryepiglottic folds, nasopharyngeal collapse, and laryngeal granuloma formation.

Secondary Gastrointestinal Conditions

Secondary gastrointestinal conditions (prevalence 16-93%) include aerophagia, esophageal deviation, esophageal dilation, delayed esophageal transit time (86%), megaesophagus, gastric bloat, gastric dilatation and volvulus, pyloric stenosis, sliding hiatal herniation (44%), gastroesophageal reflux (75%), redundant esophagus (11%), esophagitis (37%), gastritis (89%), and duodenitis (53%).

Clinical Signs

Clinical signs (and incidences) include audible breathing (100%), inspiratory stertor/stridor (69%), dyspnea (61%), respiratory distress (53%), difficulty sleeping, exercise intolerance, gagging, hyperthermia, increased respiratory noise, inspiratory dyspnea, open mouth breathing, slow inspirations with a rapid expiratory phase, syncope, ptyalism, regurgitation, and vomiting.

Diagnosis

History, clinical signs, and physical examination findings aid strongly in the diagnosis of this condition. Diagnosis is via direct visualization of the aforementioned abnormalities.

Sedated visualization of the intra-oral, pharyngeal, and laryngeal structures is simpler with the use of a temporary tracheostomy tube, with temporary extubation, or by displacing the endotracheal tube to one side.

Medical Therapy

Medical therapy is palliative or adjunctive to surgery and is a combination of veterinary in-hospital care and out-patient care; body weight management, decreasing stress, short leashed walks, maintaining a dry environment at cool temperature, and maintaining a moderate energy level status, gastrointestinal tract motility drugs, corticosteroids (parietal fibrosis, gastritis and duodenitis), antacids and sucralfate (gastric surface protector).

Surgical Treatment and Recommendations

The current recommendation is to surgically correct affected pets after 6 months of age.

Surgical Correction of the Elongated Soft Palate

Surgical correction of the elongated soft palate options include excision caudal palatoplasty (traditional cut and sew/sharp staphylectomy), split staphylectomy, H-pharyngoplasty, folded flap palatoplasty and temporary palatopexy. Palatoplasty options include bipolar sealing device, CO2/diode laser, air plasma device/plasma mediated bipolar frequency device, manual crushing, monopolar electrocoagulation, harmonic shears/scalpel, electroscalpel, low-temperature high-frequency radiosurgery, and sharp dissection (scissors or scalpel blade).

Stenotic Nares Corrections

Stenotic nares corrections include Trader’s partial amputation technique, wedge resection alaplasty (vertical and modified horizontal), incisional alarpexy (or alapexy), novel punch resection alaplasty, nares amputation, (dorsal offset) rhinoplasty, vestibuloplasty and ala-vestibuloplasty/H-pharyngoplasty.

Everted Laryngeal Saccules Excision

Everted laryngeal saccules excision (laryngeal sacculectomy) is via Allis tissue forceps, long hemostats, and Metzenbaum scissors or a #15 scalpel blade. Or electroscalpel, electrocautery, laryngeal cup forceps, or a tonsil snare.

Everted Tonsils Treatment

Everted tonsils are treated with tonsillectomy via bipolar vessel sealing device, forceps, microdebrider, bovie tip electrosurgery or tonsillectomy clamp followed by sharp excision with a crypt oversew pattern.

Laryngeal Collapse Classification and Treatment

The Leonard grading system characterizes laryngeal collapse severity:

• Stage 1: Laryngeal saccule eversion and cuneiform process collapse.
• Stage 2: Cuneiform process protrusion and is less rigid.
• Stage 3: Stages 1 plus 2 with corniculate process protrusion and loss of the rima glottidis dorsal arch.

Treatment Approaches:

• Stage 1: Elongated soft palate and nare resection.
• Stage 2: Partial arytenoidectomy and laryngeal saccule resection.
• Stage 3: Permanent tracheostomy and laryngeal resection, partial arytenoidectomy or arytenoid lateralization.

Nasopharyngeal Stenosis Treatment

Nasopharyngeal stenosis treatment includes stent placement, turbinectomy, or turbinoplasty.

Telediagnostics in Veterinary Medicine

Telediagnostics is a rapidly emerging and powerful tool evolving in the veterinary space. The portable VetGuardian telediagnostic device by Zomedica continuously monitors body temperature, pulse rate, and respiratory rate with thermal cameras and Doppler technology, and monitors movement via video camera. Multiple animals can be monitored simultaneously and measuring vital parameters while also eliminating patient physical contact minimizes patient stress and anxiety.

Postoperative Complications and Outcomes

The overall postoperative complication incidence is 0-29.5%. Gastrointestinal treatment in combination with surgery decreases the complication rate.

Surgical complications include:

• Bronchopneumonia
• Coughing
• Gagging
• Hemorrhage
• Incisional dehiscence
• Infection
• Inflammation
• Laryngeal swelling
• Nasal discharge
• Noncardiogenic pulmonary edema
• Regurgitation
• Voice change
• Vomiting
• Death

By 2 weeks post-operatively, 71% show improved respiratory signs. Overall outcome by 6 months postoperatively is excellent in 65% and good in 25%. It is thought that approximately 11-100% of dogs show significant improvement post-operatively.

Preoperative mortality rates range from 2.4-15%.

Negative prognosticators include:

• Tracheostomy
• Advanced inspiratory efforts 
• Advanced case presentation
• Advanced presurgical snoring 
• Pneumonia
• Higher brachycephalic grade (“BRisk” score)
• Laryngeal collapse
• Concurrent upper/lower airway pathology
• Both gastrointestinal and respiratory diseases present
• Laryngectomy
• Advanced American Society of Anesthesiology classification

Positive prognosticators include:

• Modified multilevel surgery vs. traditional multilevel surgery
• Early surgical intervention
• Treating gastrointestinal clinical signs

Brachycephalic airway syndrome presents a complex set of anatomical, respiratory, and gastrointestinal challenges that require careful diagnosis and a tailored approach to treatment. While medical management can provide some relief, surgical intervention remains the most effective solution for improving long-term outcomes. Advances in surgical techniques, coupled with emerging technologies like telediagnostics, continue to enhance patient care and postoperative monitoring. Despite potential complications, the majority of dogs experience significant respiratory improvement following corrective procedures. With early intervention, appropriate medical and surgical care, and diligent postoperative management, affected pets can achieve a greatly improved quality of life.