Chapter 90 Oesophagus Flashcards
At what level does oesophagus regain dorsal position (to trachea)
At tracheal bifurcation
What are the layers of the oesophagus
- Adventitis
- Muscularis
- Submucosa
- Mucosa
N.B. No serosa
What proportion of oesophagus can be resected?
20% of cervical oesophagus
50% of thoracic oesophagus
But in practice excision of >3-5cm –> increased risk of dehisence
What is the distribution of skeletal/smoth muscel in canine oesophagus?
And feline?
In dogs 100% striated
In cats cranial 2/3rds striated, caudal 1/3 smooth muscle (–> herringbone appearance with contrast as caudal 1/3rd has transverse folds, rather than longitudinal)
How is the oesophagus anchored cranially?
Via cricooesophageal tendon to cricoid cartilage
What muscles form the upper oesophageal sphinter?
Thyropharyngeus and cricopharyngeus
What is the main arterial supply to:
- Cervical oesophagus
- Cranial thoracic
- Caudal thoracic
- Terminal oesophagus
- Cervical oesophagus = Cranial and caudal thyroid arteries
- Cranial thoracic (2/3rds) = Bronchooesophageal artery
- Caudal thoracic (1/3rd) = Aorta or dorsal intercostals
- Terminal = Left gastric artery
Which veins drain the oesophagus?
External jugular, azygous and left gastric
Which nerves innervate the oesophagus
Vagus:
- Pharyngo-oesophageal nerves
- Recurrent laryngeal and para-recurrent laryngeal nerves
- Dorsal and ventral vagal branches nerves
Label the diagram
Label the diagram
Left lateral view of the canine thoracic cavity; the lung and much of the pericardium have been removed.
1, Longus colli;
2, left subclavian artery;
3, internal thoracic vessels;
4, thymus;
5, vessels in paraconal interventricular groove;
6, pulmonary trunk;
7, esophagus;
8, pulmonary veins entering left atrium;
9, left principal bronchus and dorsal and ventral vagal trunks;
10, aorta;
11, sympathetic trunk;
12, phrenic nerve;
13, caudal mediastinum;
14, diaphragm.
Label the diagram
Right lateral view of the canine thoracic cavity; the lung and much of the pericardium have been removed.
1, Diaphragm;
2, infracardiac bursa;
3, sympathetic trunk;
4, esophagus;
5, caudal vena cava;
6, plica venae cavae;
7, root of lung and phrenic nerve;
8, right vagus;
9, right azygos vein;
10, cranial vena cava;
11, longus colli;
12, trachea;
13, thymus;
14, internal thoracic vessels;
15, first rib;
16, vagosympathetic trunk.
Name the three phases of swallowing:
-
Oropharyngeal
- Oral
- Pharyngeal
- Cricopharyngeal/pharyngo-oesophageal
-
Oesophageal (if dysfunction, then broken down as follows)
- Mechanical
- Functional
- Inflammatory
- Gastrooesophageal
What nerves co-ordinate swallowing>
V Trigeminal
VII Facial
IX Glossopharyngeal
X Vagus
XII Hypoglossal
On swallow study, a bolus of food stops in front of gastrooesophageal juntion and then enters stomach at next bolus - comment on this
Can be normal
How do oesophageal transit times vary with sternal vs lateral positioning?
Slower in lateral!
(7-9 cm/s in lateral vs 3-4 cm/s in sternal)
N.B. Book misquotes these numbers implying faster in lateral!
List 6 ddx for mechanical oesophageal dysfunction
- VRA
- Mural mass lesion
- Neoplasia
- Duplication cyst
- Paraoesophageal abcess
- Oesophageal diverticula
- Stricture
- FB
- Hiatal hernia
- Gastroesophageal intussusception
What is most common cause for canine megaoesophagus?
Idiopathic
List 5 factors that contribute to higher dehisence rate in oesophagus vs SI
- Lack of serosa
- Lack of omentum
- Segmental blood supply
- Constant movement with peristalisis and respiration
- Less mobile i.e. more tension
In what layer of the oesopagus does the rich intramural plexus of anastomosing vesels sit?
Submucosa
What is the significance of the rich intramural plexus of anastomosing vesels of the oesophagus?
Thoracic oesophageal anastomoses can heal after ligation of thoracic segmental blood supply (however simultaneous ligation of thoracic AND cervical supply –> necrosis).
i.e. ischaemic necrosis usually due to damage to the intramural supply
What are post-op feeding recommendations after oesophageal surgery?
Withhold for 1-7d.
Consider G- or E-tube
What approaches can be performed for cranial thoracic oesophagus
L 3rd or 4th ICT
R 3rd, 4th or 5th ICT
Cranial MS
When performing L ICT for access to cranial oesophagus, what other step is necessary?
And on R?
Left: Ventral retraction of brachiocephalic trunk and subclavian vessels
Right: Ventral retraction of trachea +- retraction/ligation of azygous vein
What is preferred approach for caudal thoracic oseophagus
L 7th, 8th, 9th ICT
(Alternatives = transdiaphragmatic or caudal MS)
Label the diagram
Approach to the cervical esophagus.
A, Position the patient in dorsal recumbency with the neck resting on a rolled towel.
B, The skin is incised from the larynx to the manubrium, and the sternohyoid muscles are separated to expose the trachea.
C, The trachea is retracted to the right to expose the esophagus, thyroid, carotid sheath, and recurrent laryngeal nerve.
Why is simple continuous closure of oesophagus not recommended (2 points)
- Had lowest wound strenght and poorest tissue apposition in study comparing it to simple interrupted + double layer patterns.
- Doesnt permit oesophageal dilation.
Name a technique to reduce anastomotic tension following oesophageal R+A
How is this facilitated?
Partial myotomy (N.B. leaving inner muscle intact! This prevents disruption of submucosal vascular plexus. Full thickness myotomy –> necrosis)
Inject saline between muscle layers to differentiate them
What was outcome of oesophageal R+A using biofragmentable anastomosis ring
4/30 mortality
Can also staple with EEA stapler (2/18 stapled –> stricture)
List local muscle flap options for oesophageal patching in:
Cervical oesophagus
Cranial thoracic
Caudal oesophagus
List alternative materials that can be used for in-lay patches or support patching
Cervical oesophagus:
- Sternohyoid pedicle graft
- Longus colli pedicle graft
Cranial thoracic
- Internal or external intercostal vascularised pedicle
Caudal oesophagus
- Internal or external intercostal vascularised pedicle
- Diaphragmatic vascularised pedicle graft
- Stomach
And can use the following:
- Omentum
- Pericardium
- Pedicled segment of gastric wall or jejunum
- Free buccal mucosal graft
- Porcine SIS
- Lyophilized duramater
- Collagen coated vicryl mesh
- ePTFE patches
List 7 options for oesophageal substitution
- Inversed tube skin graft (staged) or based on omocervical axial pattern flap (for single stage procedure)
- Tubed intercostal musculopleural pedicle patch
- Diaphragmatic pedicle graft
- Tubed lat dorsi musculocutaneous flap
- Gastric advancement oesophagogastric anastomosis
- Gastric tubes (peristaltic and anti-peristaltic - based on gastroepiploic vessles)
- Free microvascular grafts (intestine/colon)
When performing a gastric tube procedure for oesophageal substitution, what two additonal surgical procedures shoudl be performed and why?
- Splenectomy - becuase pedicle flaps are based on gastroepiploic vessels
- Pyloromyoplastyc - to facilitate astric emptying as vagal supply to stomach likely to be disrupted
What is most common VRA?
Which is most common causing clinical signs?
Most common = aberrant R subclavian but usually asymptomatic (present in 6% of dogs)
Most common clinically significant = PRAA + L ligamentum arteriosum
How many primordial aortic arches are there?
Which involute?
6 embryonic arches
Arches 1, 2 and 5 involute
A, The six primordial embryonic arches, the dorsal and ventral aortas, and their normal development in postnatal structures. Only arches three, four, and six are retained in their original forms as adult structures.
B, Normal embryology of the aortic arches and postnatal arrangement of the vessels in dogs and cats.
Embryonic arches 1,2 and 5 involute. What is the fate of each of the other arches?
RIGHT SIDE:
- 3rd arch: Common carotid
- 4th arch: Brachiocephalic trunk + R subclavian
- 6th arch: Pulmonary artery
LEFT SIDE:
- 3rd arch: Common carotid
- 4th arch: Aortic arch
- 6th arch: Pulmonary artery + ductus arteriosus (ligamentum arteriosum)
N.B.
- L subclavian develops from L 7th intersegmental artery
- Internal carotid comes from dorsal aortas
- External carotid comes from ventral aortas
Which embryonic arch form common carotids?
3rd aortic arch
Which aortic arch forms the r subclavian and brachiocephalic trunk?
R 4th aortic arch
Which embryonic aortic arch forms aortic arch?
L 4th aortic arch
Which embryonic aortic arch is retained in PRAA?
R 4th aortic arch (instead of L 4th aortic arch)
Which embryological aortic arches form plumonary arteries
6th aortic arches
What embryonic structure forms L subclavian artery?
L 7th intersegmental artery
Which embryonic aortic arch forms the ductus arteriosus/ligamentum arteriosum?
L 6th aortic arch
Which embryonic structures form the external carotids?
And internal carotids?
External carotids: Ventral aortas
Internal carotids: Dorsal aortas
Name the VRAs
A, The six primordial embryonic arches, the dorsal and ventral aortas, and their normal development in postnatal structures. Only arches three, four, and six are retained in their original forms as adult structures.
B, Normal embryology of the aortic arches and postnatal arrangement of the vessels in dogs and cats.
C, Persistent right aortic arch (RAA). The right fourth arch, instead of the left, becomes the functional aorta. The ligamentum arteriosum (LA) extends between the left pulmonary artery and the anomalous RAA, causing constriction of the esophagus by the vascular ring.
D, Double aortic arch (DAA): both the left and the right fourth arches persist and are functional. This type of anomaly may also result in respiratory signs secondary to constriction of the trachea along with the esophagus.
E, Persistent right ductus arteriosus (RDA), essentially the mirror image of persistent RAA. The aortic arch develops normally on the left, but the right sixth arch persists as the ductus arteriosus. The RDA arises from the pulmonary artery and extends to the aortic arch, compressing the esophagus on its right side.
F, Aberrant left subclavian artery: an example of a partial vascular ring anomaly. The left subclavian arises from the persistent RAA and compresses the esophagus on its dorsal aspect as the artery traverses from right to left in the cranial mediastinum.
G, Aberrant left subclavian artery with persistent RAA. Similar to F except a left LA connects the pulmonary artery to the persistent RAA. The esophagus is dually compressed by a complete vascular ring (persistent RAA with left LA) and by a partial vascular ring (aberrant left subclavian).
H, Aberrant right subclavian artery: the right subclavian artery arises from the normal left aortic arch rather that the brachiocephalic trunk, thus compressing the esophagus on its dorsal aspect as the artery traverses to the right side.
(A, Aorta; AA, aortic arches; BCT, brachiocephalic trunk; CC, common carotid; CI, cervical intersegmental arteries; DA, dorsal aorta; EC, external carotid; IC, internal carotid; LAA, left aortic arch; LPA, left pulmonary artery; LS, left subclavian; MPA, main pulmonary artery; RPA, right pulmonary artery; RS, right subclavian; VA, ventral aorta.)
In what % of PRAA + LA dogs does ductus arteriosus remain patent?
10%
What additonal vascular anomaly is also commonly found in cases of VRA?
In what %
What is clinical significance?
Persistent cranial vena cava
Present in 45% of VRA dogs
Affects approach - retract dorsally (dont need to ligate cranial cava. Can ligate hemi-azygous if present)
Name two dog breeds predisposed to VRA
And two cat breeds
GSD and Irish Setter
Persian and Siamese
3 causes of coughing with VRA
- Aspiration pneumonia
- Tracheal compression (double aortic arch)
- CHF (e.g PDA, other congenital cardiac malformations)
List things to assess on radiograph in VRA case
And on oesophagoscopy?
Rads:
- Oesophageal dialtion
- Tracheal side relative to aorta
- Tracheal compression/deviation (focal leftward curvature with PRAA)
- Aspiration pneumonia
Oseophagoscopy:
- Rule out other causes of oesophageal compression
- Look for arterial pulse on side of oesophagus.
- Assess oesophagitis
Which VRA(s) should be approached via R ICT?
Right ligamentum arteriosum (and normal left aortic arch)
(Right aberrant subclavian although if needs be can eb approached from L)
What approach is made to treat PRAA + L LA in dogs?
And in cats?
L 4th ICT
L 5th ICT
In doubel aortic arch, how is dominant arch determined?
Angiography or echo
How does surgery for double aortic arch differ from other VRAs?
Arch divided and oversewn
What is the most common post-op complication following VRA surgery?
Persistent regurg.
What % of VRA survive to discharge?
92 - 94%
(further 18% PTS within 2 months though so overall 75% long term survival.
Of those good-excellent outcome in 90%)
In Basuñan VetSurg 2020, what was most common feline VRA?
What was STD?
What % had peristent c/s?
PRAA + L LA (and 4/20 also had aberrant L subclavian)
90% STD
69% persistent clinical signs (i.e. regurg)
List post-op management of VRA
- Elevated slurry feeding
- PPI/H2 blocker
- Analgesia
- Chest drain
What is 1 year mortality rate of dogs with congenital mega-oesophagus?
Lista salvage procedure
74%
Oesophagodiaphragmatic cardioplasty using Torres technique (i.e. excise some diaphragm neighbouring cardia then re-suture –> radial tension at cradia. Good outcome in 4/6 puppies, unsuccessful in other 2)
Name a congenital ddx for oesophageal ‘mass’
Oesophageal duplication cyst
List the three most common placed for oesophageal FB
Thoracic oonlet, heart base, caudal oesophagus
(although in non-referral cervical also v common)
In case of oesophageal FB - what else shoudl rads be assessed for?
- Aspiration pneuminia
- Pneumothorax
- Pneumomediastinum
- Pleural effusion
- Mediastinits
- Tracheal compression
NOn sx management of o-FB
Floroscopy or endoscopy using forceps or balloon.
Usually successful in >90% of cases
What is reported mortality rate following endoscopic O-FB retrieval vs surgery
Non-surgical 7% mortality
Surgical 14-43% mortality
What was mortality rate of dogs with acute oesophageal stick penetration injuries
36%!
NAme a weird, post-op cause of oesophageal perforation
Thermal injury via monopolar electrocautery and oesophageal ECG
“alternative pathway injury”
What degree of oesophageal injury leads to stricture
Circumfrential injury extending into muscular layer
What is most common cause of oesophageal stricture and in what % is this underlying aetiology?
List 6 other potential causes
Reflux uGA
46 -60% of cases
Other causes:
- Thermal injury
- Corrosive substance ingestion
- Chronic vomiting
- Radiation injury
- FB
- Doxycycline/clindamycin abx in cats
Within what time frame do post GA oesophageal strictures usually occur?
3 weeks
How is oesophageal stricture diagnosed?
Positive contrast oesophagography + oesophagoscopy (allows biopsy too, assessment of length and number of strictures too and balloonn/bougienage)
What should owners be warned re balloon/bougienage for O stricture?
Likely to need repeat procedures (overall mean 4.2 procedures)
Risk of perf
List 2 benefits of balloon dilation vs bougienage for O stricture
- Balloon applies radial strech meaning less likely to tear
- Mean procedure number with balloon 2
For bougienage 3 procedures in dogs, 5 in cats
What can be done to treat O stricture in addition to dilation ?
A ‘pre- surgery salvage’ option - what was outcome?
Intralesional steroids (triamcinolone) or Mytomycin C
Stent - 8/9 complications and 4/8 PTS.
What sx can be performed for O-stricture?
- Simple oesophagosplasty (=longitudinal inscision closed transversely - often re-stricture)
-
In-lay patch oesophagosplasy (preferred) - pedicle flaps so dependent on location
- Sternohyoideus
- Intercostal
- Pericardial
- Diaphragmatic
- R+A (often re-stricture)
-
Oesophageal substitution
- Inverse tube skin graft and free jejunal segment graft reported - only if v severe
- For cervical stricture creation of oesophagocutaneous fistula –> traction diverticulum
What % of cases undergoign balloon/bougienage for O-stricture have good outcome?
71-88%
In experimantal studies, injection of what substances reduced incidence of O stricture formation?
- Sustained release 5-fluorouracil
- Adipose derived stromal stem cells
Also good outcome following R+A with porcine SIS seeded with BM derived mesenchymal stem cells
What condition is shown in oesophagoscopy image?
Bilateral oesophageal diverticula (could say fistula i suppose if based on just image)
DDx for this?
- Oesophageal diverticulum
- GEI
- Hiatal hernia
How are oesophageal diverticula classified?
- Congenital
- Aquired
- Pulsion
- Traction
What is the difference between pulsion and traction oesophageal diverticula
Pulsion diverticulum is an outpouching of mucosa that herniates through a defect in the tunica muscularis. It is thought to be caused by increased luminal pressure as a result of a mechanical (e.g., foreign body or stricture) or functional esophageal obstruction.
Traction diverticulum is a full-thickness deviation of the esophageal wall. The term traction refers to the assumed pathogenesis, namely inflammation in an adjacent organ causing formation of an adhesion. Subsequent contraction of the adhesion pulls the esophagus outward to form a pouch.
Where have canine oesophageal diverticula been described?
What condiiton is frequently seen with them and in what %
Between heart and diaphragm (=epiphrenic diverticula)
Bronchooesophageal fistula in 50%
Name two breeds overrepresented for oesophageal diverticula and fistulae
Cairn terrier and Miniature poodle
What ‘orthopaedic’ condition has been reported with O diverticula?
HO!
WHat is the most common cause fo aquired oesophageal fistulas?
Which lung lobe is most commonly affected?
O-FB
R caudal
What is most common clinical signs of bronchooesophageal fistula?
Coughing
How is o-fistula diagnosed (aside from CT)
Contrast oesophagram
GA consideration for B-O fistula?
TIVA! or one-lung ventilation
NAme two conditions considered as cicopharyngeal dysphagia
-
Cricopharyngeal achalasia
- In patients with cricopharyngeal achalasia, the upper esophageal sphincter fails to open during the cricopharyngeal phase of swallowing, preventing the passage of food boluses from the oropharynx into the cervical esophagus.
-
Cricopharyngeal asynchrony
- Cricopharyngeal asynchrony is an incoordination between the contraction of the pharyngeal contractor muscles and relaxation of the upper esophageal sphincter. The majority of the food remains in the pharynx, with a small portion passing through the upper esophageal sphincter.
What are swallow study findings n dogs with cricopharyngeal dysphagia?
Cricopharyngeal dysphagia (i.e both cricopharyngeal achalasia and asynchrony) show:
- normal bolus formation
- adequate pharyngeal contraction
- failure or incoordination of relaxation of the cricopharyngeal sphincter.
The bolus will remain in the pharynx; some contrast may be propelled into the esophagus, and the remainder is regurgitated, aspirated, or forced into the nasal passages. It is important to differentiate cricopharyngeal dysphagia from pharyngeal dysphagia (weakness of the pharyngeal constrictor muscle) because the former is improved and the latter worsened by cricopharyngeal myotomy. Esophageal function should also be evaluated.
Label the image
Normal lateral fluoroscopic view of the pharynx at rest. Note that radiodensity is reversed in fluoroscopic images compared with conventional radiographs (i.e., air is white and bone is black).
1, Nasopharynx;
2, soft palate;
3, base of tongue;
4, epiglottis;
5, trachea;
6, cranial esophageal sphincter;
7, cranial esophagus with barium in the lumen.
WHat nerve innervated cricopharyngeus?
Glossopharygeal IX and pharyngeal branch of vagus
2 approaches for cricopharyngeal myotomy (/myectomy) +- thyropharyngeal myotomy
Ventral midline or lateral
describe lateral approach for cricopharyngeal myotomy
- An orogastric tube placed
- A skin incision is made dorsal to the larynx and ventral to the jugular vein, starting at the cranial aspect of the jugular vein.
- The subcutis and platysma are transected, and Gelpi retractors are inserted so that the sternocephalicus muscle and jugular vein are retracted dorsally and the sternohyoideus muscle ventrally.
- The thyroid cartilage is identified and loose connective tissue dissected free to expose, from cranial to caudal, the thyropharyngeus and cricopharyngeus muscles and esophagus.
- The cricopharyngeus muscle is dissected free from the esophagus laterally and dorsally, and a 2.0- to 2.5-cm section is removed from the dorsal midline, being careful to ensure that all the muscle fibers are cut without penetrating the esophageal wall.
- Place vasculr clips at edges of myotomy to facilitate identification on follow up fluoro
- The resected tissue is submitted for histologic evaluation, and the subcutaneous tissues and skin are reapposed routinely.
Comment of fluoro study
Lateral fluoroscopic view of barium swallow. Barium appears black on fluoroscopy.
Row 1, Normal dog;
- 1A, liquid barium bolus in the pharynx;
- 1B, closure of the epiglottis at the onset of swallowing;
- 1C, opening of the cranial esophageal sphincter;
- 1D, closure of the cranial esophageal sphincter and reopening of the epiglottis.
Row 2, Dog with cricopharyngeal achalasia;
- 2A, liquid barium bolus in the pharynx;
- 2B, contraction of pharynx without opening of the cranial esophageal sphincter;
- 2C, opening of cranial esophageal sphincter and reopening of the epiglottis
- 2D, closure of the cranial esophageal sphincter.
Look at this table of ddx for dysphagia
Look at this table of ddx for dysphagia
List 3 causes for continued c/s after myotomy/myectomy for cricopharyngeal dysphagia
- Failure to transect all bands
- Incorrect initial dx
- Concurrent pharyngeal/oesophaeal dysfunction
What is outcome following surgery for cricopharyngeal dysphagia
Mixed
49% complete resolution, other study 8/14 PTS
What are most common malignant tumours of canine oesophagus?
SCC
Fibrosarc
Osteosarc
Undifferentiated sarcoma
Leiomyosarcoma
What have O sarcomas been associated with
Spirocerca lupi
What is most common primary tumour of feline oesophagus?
And most common site
SCC
Cranial oesophagus
How do Spirocerca lupi end up in oseophagus?
Migrate through gastric call, into arterties, into aorta, then through aorta wall into adjacent oesophagus
How can benign spirocerca oesophageal lesions be managed
avermectins
What radiographic lesions (6) might be present with spirocerca lupi infection?
- Oesophageal mass
- Aortic aneurism
- Aortic mineralisation
- Caudl throacic spondylytis
- Peulmonary mets if malignant
- Hypertrophic osteopathy
How did dogs with malignant spirocerca infection differ from benign (6 points)?
And related to CT/oesophagoscopy apperance specifically (4 point)?
Malignant
- Older (6.5 vs 5 years)
- Lower HCT
- Higher WBC and plt
- Larger masses on rads
- More liekly to cause bronchial displacement
- Hypertrophic osteopathy
- Neutered female (vs intact male)
CT/oesophagoscopy
- More irregular surface
- Mineralized foci
- Rarely have hypoattenuating foci (vs more common in benign, weirdly)
- Reltive hypoperfusion
Can S lupi be diagnosed wit faecal smear?
Yes occassionally but eggs only shed for short period of time so false negative easy!
What is typical apperance of O SCC
Circumfrential, ulcerated, friable
Where do O. leiomyomas/leiomyosarcomas usually occur
Caudal O
Comment on endoscopic biopsy for O masses
Usually diagnostic for SCC but unrewarding for smooth muscle masses and sarcomas
What % of oesophageal masses have mets?
50%
List 4 adjuctive options for oesophageal neoplasia
- Radiation
- Photodynamic therapy (SCC)
- Transendoscopic laser ablation (Spirocerca sarcoma)
- Snare electrocautery (Spirocerca sarcoma)
What was MSt for dogs undergoign sx for O sarcoma
300d
but 50% died peri-op
