Surgery of the GIT, liver and pancreas 1, 2 +3 Flashcards
What is a primary cleft palate?
Failure of fusion of the primary palate (lips and premaxilla)
What is a secondary cleft palate
Failure of fusion of the secondary palate (hard and soft palates)
What are the causes of a secondary cleft palate?
Attributed to inherited, nutritional, hormonal, mechanical and toxic factors
More common in brachycephalic breeds, also in Schnauzer, Labrador, Cocker Spaniel, Dachshund, GSD and cats (esp. Siamese)
What are the clinical signs of a cleft palate?
Drainage of milk from nares
Coughing, gagging or sneezing while eating
Poor growth
Chronic rhinitis
Cough
What is the importance of an early cleft palate diagnosis?
Early diagnosis allows tube feeding until animal is 8-12 weeks old, when tissues are better able to hold sutures, the cleft has often narrowed, the oral cavity is bigger (more room to work) and anaesthesia is better tolerated.
Describe medical treatment for a cleft palate
Medically treat patients with pneumonia and tube feed until they are better surgical candidates
Describe repair of a primary cleft palate
Surgical reconstruction of the medial and lateral components of the cleft and skin
Describe repair of a secondary cleft palate
Secondary clefts carry a high risk of complications (dehiscence) due to tension and several procedures may be required, esp. in young animals.
They are closed by various mucosal flaps with/without tension-relieving incisions
List the complications of cleft palate repair
- Dehiscence is usually due to tension, motion or excessively tight sutures.
- Persistent chronic rhinitis is common.
- Young palates grow rapidly: reconstructed palates can become thin and develop oronasal fistulae that can be corrected at 8-10 months of age.
When is a maxillectomy/mandibulectomy indicated?
Used to remove sections of the maxilla and mandible of various sizes for wide excision of both benign and malignant masses.
Describe closure of a mandibulectomy/maxillectomy
Closed in 3 layers – buccal mucosa, muscular / subcutaneous tissue and skin
Describe post-operative treatment following a mandibulectomy/maxillectomy
Supportive treatment with antibacterials, anti-inflammatories and a pharyngostomy or gastrostomy tube for feeding are often required.
Dogs tolerate mandibulectomy / maxillectomy much better than cats
What is the most commonly diagnosed salivary gland disease in 1. cats and 2. dogs
Cats = neoplasia
Dogs = salivary mucocoele
What is salivary mucocoele
Subcutaneous or submucosal cavity containing saliva from a disrupted salivary gland or duct
In dogs the sublingual gland or duct is most often affected
Describe the aetiology and predisposition of salivary mucocoele
Trauma, neoplasia, sialoliths (mineralised “stones” forming in the salivary glands or ducts), foreign bodies or iatrogenic damage.
Most are idiopathic.
GSDs, Greyhounds, Poodles, Dachshunds and Australian Silky Terriers may be predisposed.
List the clinical signs of salivary mucocoele
- Painless fluctuant swelling (may be acutely painful).
- Sublingual mucocoeles = dysphagia, ptyalism, blood-tinged saliva.
- Pharyngeal mucocoeles = inspiratory stridor, coughing or respiratory distress
List the DDx of salivary mucocoele
- Salivary gland enlargement
- Cervical lymphadenopathy
- Haematoma or seroma
- Oedema
- Emphysema
- Enlarged thyroid
How is salivary mucocoele diagnosed?
- History and clinical signs.
- Aspiration of mucoid, stringy fluid, often blood tinged with a low cellular content. Staining smears with PAS may confirm the presence of mucin.
- Sialography with positive contrast material can lateralise the lesion (bilateral in up to 20% of dogs).
- Ultrasonography can help to lateralise the lesion
How is salivary mucocoele treated?
- Drainage is only palliative and >95% recur.
- Mandibular and sublingual sialadenectomy is more successful coupled with drainage of the sialocoele at the time of surgery ± drain placement.
List the possible complications of salivary mucocoele treatment
Haemorrhage, seroma, infection, recurrence and hypoglossal nerve paralysis
In which animals are nasal polyps most commonly seen?
Young cats
What are nasal polyps?
Pedunculated benign inflammatory lesions of the mucous membranes of the nasopharynx, auditory tube or middle ear
List the clinical signs of nasal polyps
Upper airway obstruction
Dysphagia
Dysphonia
Otitis externa if tympanic membrane disrupted
Horner’s Syndrome if tympanic bulla affected with pressure on sympathetic trunk
How are nasal polyps diagnosed?
- Direct visualisation under GA in nasopharynx or ear canal.
- Radiography may reveal a soft tissue density in the pharynx or bulla
How are nasal polyps treated?
Surgical excision
Medical treatment with oral prednisolone may reduce recurrence
What is the main complication with polyps?
Recurrence, esp. if underlying inflammation is not controlled or there is failure to completely excise the polyp
What are pharyngeal stick injury and/or abscess?
Occur in both dogs and cats due to penetration of the pharyngeal mucosa by a variety of objects
How do patients with a pharyngeal stick injury and/or abscess present?
Acute onset of marked pharyngeal discomfort with gagging, headshaking, pawing at mouth, opening mouth, hypersalivation, pain on opening mouth and painful retropharyngeal swelling with surrounding oedema.
How are pharyngeal stick injuries/abscesses diagnosed?
History, clinical signs, digital examination of pharynx, radiography, ultrasound
How are pharyngeal stick injuries/abscesses treated?
- Remove FB (if present), arrest haemorrhage without compromising blood supply to the area and debride the wound
- Endoscopy
- Leave wounds open to drain and heal by second intention
- Antibacterial therapy
When is a tonsillectomy performed?
For chronic, recurrent unresponsive tonsillitis or tonsillar neoplasia
Describe how to perform a tonsilectomy
- Place a cuffed ET tube and pack the pharynx with swabs
- Grasp the tonsil and retract from the tonsillar crypt
- Then either sharply excise with scissors (controlling haemorrhaging vessels individually with ligatures or electrocautery) or clamp with a curved haemostat then ligate en masse and excise.
- Close the tonsillar crypt with a continuous suture to help control haemorrhage
In which places do oesophageal foreign bodies most commonly lodge?
Where distension of the oesophagus is limited by surrounding structures:
- Thoracic inlet
- Heart base
- Caudal oesophagus just in front of the cardia
How does a patient with an oesophageal foreign body present?
- History of FB ingestion
- Regurgitation
- Retching/gagging
- Hypersalivation
- Restlessness
- Lethargy
- Inappetence
What are the signs of a patient with an oesophageal FB that has lead to an oesophageal perforation?
Pneumothorax, mediastinitis, pyothorax or pleuritis may occur
- Pyrexia, depression and respiratory distress
How is an oesophageal FB diagnosed?
Thoracic radiographs
Oesophagoscopy
How is an oesophageal FB treated?
- Endoscopic removal is possible in about 90% of cases. If you do not have access to an endoscope, consider referral
- If the foreign body is firmly lodged, do not force it as this may cause perforation.
- Push the FB into the stomach via endoscopy or fluoroscopy: bones can be allowed to digest unless they cause clinical signs, other objects can be retrieved via gastrotomy
Describe the procedure of oesophageal FB removal following extraction
- Inspect the oesophageal lining for ulcers or tears
- May need to use a feeding tube
- Large perforations may require drainage/surgical repair
List the potential complications of oesophageal FB removal
Oesophagitis, ischaemic necrosis, dehiscence, leakage, infection, fistula, stricture formation, perforation of the aorta or pulmonary artery by the foreign body during removal (rapidly fatal!)
What are vascular ring anomalies?
Developmental anomalies of the aortic arches in which the oesophagus and trachea are encircled and constricted by blood vessels
Most cases of vascular ring anomalies have which feature?
A persistent right aortic arch
A persistent right aortic arch is inherited in which breeds?
German shepherds
Irish setters
How are vascular ring anomalies treated?
Ligation and division of the least important vessel forming the ring (ligamentum arteriosum in PRAA).
Surgery should be done as soon as possible as medical management has poor results
What is a hiatal hernia?
Herniation of cardia of stomach through oesophageal hiatus
A hiatal hernia is associated with which condition?
Gastroesophageal reflux
How is a hiatal hernia treated?
In persistent herniation, combined suture reduction of oesophageal hiatus, oesophagopexy and left fundic gastopexy
Guarded prognosis
When is gastrotomy indicated?
Foreign body removal
Exploratory reasons
Describe the surgical approach of a gastrotomy
- Ventral midline coeliotomy.
- Pack off stomach and stabilise region of incision on the avascular area between the greater and lesser curvatures with 3-4 stay sutures.
- Incise stomach (mucosa is quite tough) and explore.
Describe surgical closure following a gastrotomy
2 layers
Inverting pattern
Simple continuous
Then Cushing or Lembert sutures
Lavage abdomen before closure
What happens in gastric dilatation and volvulus?
- The pylorus and proximal duodenum move ventrally then cranially, with the pylorus migrating from right to left and ending up dorsal to the oesophagus.
- Gas and fluid rapidly accumulate in the stomach and cause gastric distension
What are the risk factors for GDV?
- Pure breed large or giant breed
- Increased thoracic depth to width ratio
- Inherited
- Feeding fewer meals per day
- Eating rapidly
- Aggressive or fearful temperament
- Decreased food particle size
- Exercise or stress following a meal
- The Gordon setter, standard poodle, Weimaraner, Irish setter, great Dane, Bassett hound and St. Bernard are at greatest risk
Describe the haemodynamic effects of GDV
Increased intraabdominal pressure due to gastric distension reduces abdominal blood flow and venous return to the heart leading to cardiogenic shock.
Occlusion of splenic vessels frequently causes splenic enlargement and congestion
How does GDV cause respiratory dysfunction?
Pressure on the diaphragm from the distended stomach reduces diaphragmatic movement and causes dyspnoea
How does GDV cause cardiac dysfunction?
Reduced coronary blood flow and myocardial depressant factor from compromised abdominal organs cause myocardial ischaemia / necrosis and cardiac arrhythmias (premature ventricular contractions and ventricular tachycardia).
How does GDV cause gastric necrosis?
Increased intragastric pressure compresses gastric wall blood vessels and reduces perfusion
How does GDV potentially cause septic/endotoxic shock?
Mucosal ischaemia in the stomach and intestine compromises mucosal integrity and allows bacterial translocation