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).
What methods can be used for closure of esophageal resection and anastomosis?
Single layer interrupted, double layer interrupted, stapling instruments, biofragmentable anastomosis ring.
Nutritional requirements should be provided through a G or E-tube for 1 week.
What are the two types of esophageal patching?
On-lay: used to reinforce existing esophagus.
In-lay: used to to partially replace the esophagus.
What are some materials that have been successfully used for esophageal patching?
Omentum, pericardium, local muscle flaps, stomach, intestine (after mucosal stripping), porcine small intestinal submucosa, lyophilized dura mater, Vicryl mesh, expanded PTFE patches.
The omentum is particularly useful for the caudal thoracic esophagus. Pedicle grafts of the internal and external intercostal muscles have also been used in the thorax, as has the diaphragm.
Sternothyroideus and longus colli muscles have been successfully used for patching of the cervical esophagus.
What techniques can be used for esophageal substitution?
Cervical esophagus: inverse tubed skin graft, omocervical pedicle graft (for single stage inverse tubed skin graft).
Thoracic: tubed intercostal musculopleural pedicle graft, diaphragmatic pedicle graft, tubed latissimus dorsi musculocutaneous flap, free microvascular grafts of the intestine (colonic preferred due to larger size of middle colic vessels).
Caudal thoracic: gastric advancement and esophagogastric anastomosis, isoperistaltic and antiperistaltic gastric tubes created from the greater curvature of the stomach (may be better than gastric advancement due to risk of esophagitis, vomiting, and herniation of other abdominal organs with advancement technique). These techniques should be combined with a pyloromyoplasty technique to enhance gastric emptying due to likely disruption of the vagus nerve.
What is the most common vascular ring anomaly?
Persistent right aortic arch with a left ligamentum arteriosum.
In what percentage of dogs is the ductus arteriosus patent in dogs with a persistent right aortic arch?
10%
In what percentage of dogs with a vascular ring anomaly is a persistent left cranial vena cava reported?
45%
Name the following vascular ring anomalies.
Are large or small breed dogs more frequently affected by persistent right aortic arch?
Large breed (92% are >15kg). German shepherds and Irish setters are at increased risk.
What is the most common clinical sign with a PRAA?
Regurgitation after weaning.
What are some radiographic findings that are suggestive of PRAA?
Focal leftward tracheal deviation at the level of the heart, descending aorta on the right side of the esophagus, cranial esophageal dilation over the base of the heart.
What imaging techniques might be useful for diagnosis of PRAA?
Radiography +/- contrast, esophagoscopy, fluoroscopy, CT angiography.
What finding on esophagoscopy is suggestive of a PRAA?
An aortic pulse on the right side of the esophagus.
What is the normal surgical approach for PRAA in dogs and cats?
Dogs: left 4th intercostal.
Cats: left 5th intercostal.
Does a left persistent vena cava require ligation during PRAA repair?
No, although if a prominent hemiazygous vein is also present it should be divided and ligated.
What nervous structure should be carefully preserved during PRAA repair?
The vagus nerve and the left recurrent laryngeal nerve that loops caudally to the ligamentum.
Is plication of the redundant dilated cranial esophagus using Lembert gathering sutures recommended following PRAA transection?
No, does not improve the ability of the esophagus to propel food aborally.
How is the ligamentum arteriosum transected?
Double ligated with silk and transected.
In the case of double aortic arch, which aortic arch is removed?
Angiography is used to determine the dominant arch. The non-dominant arch is transected between vascular clamps and oversewn.
What is the most common complication following PRAA repair?
Ongoing regurgitation and aspiration pneumonia.
What factors might affect the prognosis for dogs undergoing PRAA correction?
Degree of esophageal dilatation and constriction, severity of debilitation, presence and severity of pre-existing aspiration pneumonia.
Varied outcomes reported in the literature.
What is congenital generalized megaesophagus?
Generalized defect in motor function of the esophagus likely due to defect in vagal afferent innervation. Results in distension of entire esophagus.
74% of affected puppies die by 1-year of age.
What is the treatment for an esophageal duplication cyst?
Surgical excision resulted in good outcome in 1 case report. May only require surgical excision if causing compression of adjacent structures.
What are the most common esophageal foreign bodies in dogs and cats?
Dogs: bones
Cats: fishhooks, needles and string
What are the most common locations for esophageal foreign bodies to lodge?
Thoracic inlet, heart base, caudal esophagus (where extraesophageal structures restrict esophageal dilation).
What breeds of dog are most prone to esophageal foreign bodies?
Terrier breeds. Normally younger than 3 years of age.
What imaging techniques can be used to diagnose an esophageal foreign body?
Radiography +/- contrast, esophagoscopy (both therapeutic and diagnostic).
What are some potential sequelae of chronic esophageal foreign bodies?
Pneumomediastinum, pneumothorax, mediastinitis, pleuritis, pyothorax, mediastinal abscess, bronchoesophageal, tracheoesophageal, or aortic esophageal fistula.
How can an esophagram be used to aid in surgical decision making when an esophageal perforation is identified following foreign body removal?
If leakage is compartmentalized around the site of perforation the patient may be able to be managed conservatively. Large migration of contrast is an indication for surgical repair.
What surgical approach might be effective for esophageal foreign bodies located between the heart and the diaphragm?
Gastrotomy via midline incision +/- diaphragmatic incision.
Should repair of esophageal perforations be supported with a local flap of muscle or omentum?
Yes, if possible.
How long should oral intake of food and water be withheld following repair of esophageal perforation?
3-7 days.
What are some potential complications of esophageal foreign body removal?
Hemorrhage (may be fatal if perforation of the aorta or pulmonary arteries occur), esophagitis, aspiration pneumonia, ischemic necrosis, rupture, dehiscence, leakage, infection, fistulas, esophageal diverticula, stricture.
Do acute esophageal penetrating injuries have a better or worse prognosis than oropharyngeal injuries?
Worse prognosis, mortality rate of 36% in one study.
Midline cervical approach is recommended for exploration. May require open wound management until tissues are healthy enough if damage is severe.
What are surgical treatment options for paraesophageal abscessation?
Abscess drainage and lavage +/- partial resection of the abscess wall, resection of involved lungs if required, cavity omentalization, thoracic drain placement.
What is the most common cause of esophageal stricture?
Esophageal reflux during anesthesia. Generally present within 3 weeks of anesthesia.
What imaging techniques are useful in the diagnosis of esophageal stricture?
Positive contrast esophagography and esophagoscopy. Esophagram may be more useful as allows for determination of number, location and length of the strictures. Multiple strictures are diagnosed in 38% of cases.
What is the preferred treatment for esophageal stricture?
Bougienage or balloon dilatation (high rate of recurrence and dehiscence after surgical excision).
Esophageal perforation occurs in 4-11% of patients undergoing balloon dilatation, and 4% after bougienage.
Stenting has also been described but can result in stent migration, discomfort, and tracheoesophageal fistula formation.
What are the surgical treatment options for esophageal stricture?
Esophagoplasty, esophageal resection and anastomosis, patch esophagoplasty, esophageal substitution.
Esophagoplasty (transverse closure of a longitudinal incision) and RnA are rarely possible due to the length of strictures.
In-lay patch esophagoplasty has been described using pedicle grafts of the sternothyroideus, diaphragm, intercostals and pericardium.
What are the major complications associated with treatment of esophageal stricture?
Perforation and recurrence of clinical signs. Good outcomes reported in 71-88% of patients after balloon dilatation or bougienage.
What are the two types of esophageal diverticula?
Pulsion: outpouching of mucosa secondary to increased intraluminal pressure.
Traction: full thickness deviation of the esophageal wall secondary to adhesions and outward pulling the esophagus.
In what location do esophageal diverticula occur in small animals?
Between the heart base and the diaphragm.
Small breed dogs around 3 years of age most commonly affected.
What are some potential sequelae of esophageal diverticulum?
Esophagitis, esophageal obstruction secondary to ingesta impaction, bronchoesophageal fistulas or adhesions to adjacent lung lobes.
What imaging techniques are useful for diagnosis of esophageal diverticula?
Radiography +/- positive contrast (in instances of bronchoesophageal fistula may see consolidation of the caudal lung lobe), esophagoscopy, CT.
What surgical techniques are reported for repair of esophageal diverticula?
Simple diverticula can be resected using a surgical stapler.
Multiple or large diverticula may require RnA, esophageal substitution or use of an in-lay patch.
Resection of lung lobes might be required if bronchoesophageal fistula is present.
What is the prognosis for esophageal diverticula?
Good for simple cases, guarded if extensive repair is required or fistula is present.
Which lung lobe is most commonly affected in dogs with bronchoesophageal fistula?
Right caudal.
Most fistulas are acquired and secondary to esophageal foreign body.
What is the most common clinical sign associated with bronchoesophageal fistula?
Coughing when drinking
What imaging techniques are most useful for diagnosis of bronchoesophageal fistula?
Contrast esophagram or CT. Bronchoscopy and esophagoscopy may fail to identify the fistula.
Why is anesthesia challenging in cases of bronchoesophageal fistula?
Communication of the lungs with the esophagus leads to leakage of anesthetic gasses. Total intravenous anesthesia may be preferable.
What is cricopharyngeal dysphagia?
Swallowing disorder characterized by cricopharyngeal achalasia (upper esophageal sphincter fails to open) or asynchrony (incoordination of the upper esophageal sphincter and pharyngeal constrictor muscles).
Thought to be a congenital condition.
What imaging modality is most useful for diagnosis of cricopharyngeal dysphagia?
Fluoroscopic swallow study.
What condition is it important to differentiate cricopharyngeal dysphagia from?
Pharyngeal dysphagia (weakness of the pharyngeal constrictor muscles) as cricopharyngeal myotomy will result in a worsening of clinical signs in this instance.
What is the treatment for cricopharyngeal dysphagia?
Cricopharyngeal myotomy or myectomy. Can be performed either via a lateral or a ventral approach. Some authors recommend combining with a thyropharyngeal myotomy or myectomy.
Label the following structures.
What are some described differentials for dysphagia?
What is the prognosis for cricopharyngeal dysphagia?
Considered good to excellent in young dogs.
Prognosis may be worse in dogs with structural or functional disease (i.e. myasthenia gravis), or in dogs with concurrent aspiration pneumonia.
What are some complications associated with cricopharyngeal myotomy for cricopharyngeal dysphagia?
Continued signs of dysphagia (failure to transect all the muscle bands, incorrect diagnosis, concurrent pharyngeal or esophageal dysfunction), recurrence of dysphagia due to fibrosis.
What are the most common esophageal tumours in dogs and cats? What are their most frequent locations?
Dogs: SCC, leiomyosarcoma, osteosarcoma, fibrosarcoma (OSA and fibrosarcoma often associated with spirocercosis). Typically in the caudal esophagus.
Cats: SCC. Typically in the cranial esophagus.
What imaging techniques are useful for the diagnosis if esophageal neoplasia?
Radiographs +/- contrast, esophagoscopy, CT. Biopsies obtained via esophagoscopy might be useful for diagnosis of SCC, but often undrewarding for sarcomas and smooth muscle tumours.
Microcytic anemia and neutrophilia might be observed on CBC, spirocerca lupi ova might be detected in the feces (although uncommon).
What is the metastatic rate for esophageal neoplasia at the time of diagnosis in dogs?
50%
What is the prognosis for esophageal neoplasia in dogs?
Typically very poor, although low-grade leiomyosarcomas may be associated with longer survival.
Complete excision with 1cm margins recommended for sarcomas (smooth muscle tumours may be more marginally excised).
