23. Surgical diseases of the trachea. Collapse of the trachea. Diagnosis and therapy

What are examples of surgical diseases of the trachea?

1. Tracheal collapse

2. Tracheal neoplasia

3. Foreign bodies

4. Tracheal rupture

What is tracheal collapse?

A progressive, irreversible condition of the lower airways associated with cough and varying degrees of airway obstruction

What causes airway obstruction in tracheal collapse?

Unknown: multifactorial (genetics, allergy, cartilage degeneration, nutrition, neurological)

Decreased glycosaminoglycan content of cartilage rings → weakening of tracheal cartilages → loss of support of dorsal tracheal membrane → collapse into the lumen

Which breeds are predisposed to tracheal collapse?

Toy and small breeds (Poodles, Pomeranians, Chihuahuas, Pugs), brachycephalic dogs, obese dogs, middle-aged dogs (over 7 years)

What are the two types of tracheal collapse?

Cervical and thoracic

When does cervical tracheal collapse occur?

During inspiration due to low intrapleural pressure

When does thoracic tracheal collapse occur?

During expiration due to high intrapleural pressure

Is cervical tracheal collapse fixed or dynamic?

Can be fixed or dynamic

Is thoracic tracheal collapse fixed or dynamic?

Always fixed

What are some clinical signs of tracheal collapse?

Varying degrees of cough (goose-honking), waxing & waning dyspnoea, exercise intolerance & cyanosis. Syncopal episodes.

What are the grades of tracheal collapse?

• Grade 1: 25% reduction in lumen diameter, cartilage maintain normal C-shape, slightly pendulous membrane

• Grade 2: 50% reduction in lumen diameter, cartilage partially flattened, widened & pendulous membrane

• Grade 3: 75% reduction in lumen diameter, cartilage flat, membrane almost in contact w/ dorsal cartilage

• Grade 4: 90-100% lumen is obliterated, cartilage flat & may invert dorsally, membrane in contact

How is tracheal collapse diagnosed?

1. Signalment, history, clinical signs

2. Palpation: may elicit coughing, but is not reliable for diagnosis

3. Radiographs: LL, DV

4. Fluoroscopy: direct visualisation of abnormal tracheal dynamics during all phases of respiration

5. Tracheoscopy: visualisation of collapse during inspiration and expiration

What are some medical treatments for acute tracheal collapse?

Sedatives, cough suppressants (butorphanol PO), short-acting corticosteroids, stabilise with O2

What are some medical treatments for chronic tracheal collapse?

Similar drugs to acute treatment, environmental modification, nebulisation, bronchodilators (theophylline), diazepam, mucolytics, prednisone, weight reduction

What are some surgical treatments for tracheal collapse?

• Grade 1 and 2: Dorsal tracheal plication, horizontal mattress sutures.

• Grade 3 and 4: Extraluminal prosthetic tracheal rings, extraluminal spiral prosthesis, Intraluminal stents

How common are tracheal tumours?

Very rare

What are some types of tracheal tumours?

Lymphosarcoma (cats), squamous cell carcinoma, adenocarcinoma

What are some clinical signs of tracheal tumours?

Dyspnoea, weight loss, mass in ventral neck

How are tracheal tumours diagnosed?

Palpation, lymph node biopsy, tracheoscopy, X-ray

What is the treatment for tracheal tumours?

Surgery (if small and benign), tracheal resection and anastomosis. Complete excision of malignant tumours is impossible

What are some causes of tracheal foreign bodies?

Inhalation of teeth, bone, food, rocks

What are some clinical signs of tracheal foreign bodies?

Cyanosis, coughing, dyspnoea

How are tracheal foreign bodies diagnosed?

X-ray, tracheobronchoscopy

How are tracheal foreign bodies treated?

1. Manual removal: Endoscopy; Turn animal upside down; Insert foley catheter past foreign body, slightly inflate cuff and gently pull back

2. Surgical removal/tracheotomy: Thoracotomy or enter through the neck

What can cause tracheal rupture?

Overinflation of tracheal cuff during intubation or trauma

What are some clinical signs of tracheal rupture?

Stridor, pneumothorax, coughing, subcutaneous emphysema, anorexia

How is tracheal rupture diagnosed?

History, tracheoscopy, CT scan

What is the treatment for tracheal rupture?

Cage rest, oxygen, sedatives, surgical repair (suturing)

What is a tracheostomy?

Surgically created opening into the trachea allowing air to bypass the nose, mouth, nasopharynx and larynx

What are some indications for a temporary tracheostomy?

Upper respiratory tract obstruction (neoplasm, trauma, anaphylaxis, defects)

What are some types of temporary tracheostomy?

Transverse flap, tracheal flap, vertical tracheostomy

What are some indications for a permanent tracheostomy?

Unresolved upper respiratory tract condition

How is a permanent tracheostomy performed?

Cervical midline approach over 4-6th tracheal rings → separate sternohyoid muscles incise down to mucosa in a rectangle → make I- or H-shaped incision → intradermal & interrupted sutures at corners → close w/ simple continuous.

What post-operative care is important after a permanent tracheostomy?

Antibiotics (5-7 days), avoiding water contact with the stoma