Esophagus Flashcards
According to Bascunan 2020 in Vet Surg what is the most common vascular ring anomaly in cats, and what is the percentage of cats that have persistent clinical signs post-op?
PRAA most common (85%).
Persistent clinical signs in 69% of cats, including continued megaesophagus in 31%.
According to Conte 2020 in Vet surg was an anatomic difference observed between the esophageal hiatus of brachycephalic dogs and normal dogs?
Yes, brachycephalic dogs had a larger esophageal hiatus:aorta ratio, as well as a larger esophageal hiatus in weight matched pairs.
In a case series by Regier 2021 in Vet Surg, was concurrent ligation of a PRAA and aberrant left subclavian artery associated with any short or long term complications?
No complications were reported and all patients seemed to tolerate subclavian ligation without apparent negative effects.
In a study by Winston 2022 in Vet Surg which described the use of Heller myotomy and Dor fundoplication for the treatment of lower esophageal sphincter achalasia, what was the improvement in owner scores for vomiting/regurgitation and bodyweight?
Improvement in vomiting/regurgitation by 180%, improvement in bodyweight by 63%.
Post-op videofluoroscopic studies improved in 6/9 available dogs.
According to Jones 2019 in JAVMA, what 4 factors were associated with an increased risk of post-operative gastroesophageal reflux in dogs?
Male, overweight, gastrointestinal surgery, need for a dexmed CRI post-operative.
In a study by Grimes 2020 in JAVMA, what was the percentage survival to discharge for patients with gastroesophageal intussusception? What 2 factors resulted in an increased risk of persistent regurgitation post-operative? What was the MST?
88% of treated dogs survived to discharge.
Persistent regurgitation was more likely in acute cases or if previously diagnosed with megaesophagus.
The MST was 995 days. German shepherds and male dogs were overrepresented.
In a study by Beer 2022 in JAVMA, what were 3 factors associated with non survival to discharge for dogs undergoing surgical intervention for esophageal foreign bodies? What was the post-operative complication rate?
Survival to discharge was 75%. Factors associated with non-survival included placement of gastrostomy tube, presence of esophageal perforation, and thoracotomy.
Overall post-operative complication rate was 50%.
In a study by Shua-Haim 2023 in VRU, what were the most common CTA findings in dogs with a double aortic arch (4)? Which aortic arch tended to be dominant?
Aberrant right subclavian (83%), segmental esophageal constriction (100%) and dilation, marked tracheal luminal compression (100%), leftward deviation of the trachea at the level of the bifurcation of the aortic arches (100%).
The left arch tended to be dominant.
The most common clinical sign was regurgitation (100%), followed by decreased BCS and coughing.
In a study by Luciani 2022 in JVIM, what proportion of dogs with sliding hiatal hernia presented with only respiratory signs?
17/67 (25%) dogs had only respiratory signs, 28/67 exclusively GI, and 22/67 mixed.
Brachycephalic dogs were more likely to present with respiratory signs, in respiratory distress with radiographic evidence of aspiration pneumonia, and were younger.
What are the layers of the esophageal wall?
Adventitia, muscularis, submucosa and mucosa.
What is the difference between the muscularis of the esophagus of the dog and cat?
The muscularis of the esophagus is striated muscle for the entire length in dogs, changes to smooth muscle in the terminal esophagus in cats.
The inner layer of the muscularis blends with circular and oblique fibers of the stomach. The outer layer blends with the longitudinal muscles of the stomach.
Which muscles function as the upper esophageal sphincter? What functions as the lower esophageal sphincter?
Thyropharyngeus and cricopharyngeus muscles.
A thickening of the circumferential striated muscle layer at the gastroesophageal junction may act as a lower esophageal sphincter.
What is the vascular supply to the different segments of the esophagus?
Cervical: cranial and caudal thyroid arteries, external jugular veins.
Cranial two thirds of the thoracic esophagus: bronchoesophageal artery, azygous vein.
Caudal third of the thoracic esophagus: branches of the aorta or dorsal intercostal arteries, azygous vein.
Abdominal esophagus: left gastric artery and vein.
Label the following diagram.
Label the following diagram.
What can cause swallowing disorders?
Mechanical obstruction: foreign bodies, strictures, tumours, vascular ring anomalies, hiatal hernias, gastroesophageal intussusception.
Functional obstruction: neuromuscular disorders.
Inflammatory disorders: esophagitis.
What factors are thought to contribute to a higher rate of esophageal dehiscence than other regions of the GI tract?
Lack of serosa, segmental blood supply, lack of omentum, constant motion due to swallowing and respiration, tension at the surgical site.
Does ligation of the thoracic segmental blood supply to the esophagus result in esophageal necrosis?
No, so long as the cervical and abdominal portions of the esophagus is intact and the rich intramural plexus is preserved. Additional ligation of the cervical blood supply results in esophageal necrosis at the thoracic inlet.
It is more likely that esophageal necrosis results from disruption to the intramural plexus rather than the segmental vascular supply.
Describe the phases of normal swallowing.
Describe the surgical approaches to the various locations of the esophagus?
Cervical: ventral midline with separation of the sternohyoideus muscles and tracheal retraction to the right.
Cranial thoracic: left 3rd, 4th, or right 3rd, 4th, or 5th intercostal thoracotomy. Alternatively a cervical midline approach can be extended with a cranial median sternotomy.
Caudal thoracic: left 7th, 8th, or 9th intercostal thoracotomy (left is preferred as it avoids the vena cava).
What closure pattern is recommended in the esophagus?
Either single layer simple interrupted or double layer interrupted pattern.
How long should food and water be withheld from patients undergoing esophagostomy?
24-48 hours
What length of esophagus can be safely excised?
20% of the cervical and 50% of the thoracic esophagus has been safely excised experimentally, however >3-5cm is generally associated with an increased risk of dehiscence.
What is one surgical technique that may be used to reduce anastomotic tension on an esophageal closure?
Circumferential partial myotomy 2-3 cm proximal or distal to the anastomosis (only the outer muscular layer is incised, preserving the submucosal vascular plexus).
