Oesophagus

Question 1

Embryology of oesophagus
- sources
- time frame
- change in length
- arterial supply

Answer 1

From two sources: pharyngeal gut and pregastric foregut
4 weeks: respiratory diverticulum
Closure of diverticulum by tracheo-oseophageal folds, caudally to cranially
Forms the tracheo-oesophageal septum
As the embryo grows the oesophagus lengthens and lumen is vacuolised
Blood supply cranially from branchial arteries, caudally from aortic branches

Question 2

Constrictions of oesophagus

Answer 2

15-17cm - upper oesophageal sphincter (pharyngeo-oesophageal constriction)
23cm - aortobronchial constriction
38-40cm - lower oesophageal sphincter (diaphragmatic constriction)

Question 3

AJCC divisions of oesophagus and measurements

Answer 3

Cervical: 0-18cm, hypopharynx to thoracic inlet (incl UOS)
Upper thoracic: 19-24cm, thoracic inlet to inferior border of azygos vein
Middle thoracic: 24-32cm, inferior border of azygous vein to inferior pulmonary veins
Lower thoracic: 32-40cm, inferior pulmonary veins to stomach (incl LOS)

Question 4

Antireflux structures of the GOJ (7)

Answer 4

1. Lower oesophageal sphincter
2. Angle of His: sling of oblique fibres in gastric cardiac musculature along with clasp of circular fibres in the distal oesophagus: contract to make the angle more acute
3. Pinchcock action of diaphragmatic crura
4. Rosette of loose oesophageal mucosa around the GOJ
5. Length of intra-abdominal oesophagus
6. Gastro-oesophageal flap valve: angle of entry of oesophagus into stomach

Question 5

Layers of the oesophagus (7)

Answer 5

Mucosa: non-keratinised stratified squamous epithelium + inflammatory cells
- at GOJ is columnar epithelium
Lamina propria: contains blood vessels, lymphatics and nerves + inflammatory cells
Muscularis mucosa: allows crinkling of the mucosa in a non-distended state
Submucosa: loose connective tissue, mucus-secreting glands, Meissner plexus (specialised nerve cells)
Muscularis propria: deep circular and superficial longitudinal
Loose adventitia but no serosa

Question 6

Where do motility disorders of the oesophagus affect and why?

Answer 6

Distal oesophagus - they are disorders of smooth muscle

Question 7

Arterial supply of the oesophagus (5)

Answer 7

Segmental
- inferior thyroid, carotid, subclavian, thyrocervical, costocervical, superior thyroid,vertebral
- bronchial arteries (branches of the aorta)
- broncho-oesophageal artery (inconstant)
- inferior phrenic
- left gastric

Form rich anastomoses within the submucosa

Question 8

Lymphatic drainage of the oesophagus: pattern, and orders of nodes (3)

Answer 8

45% drain directly into thoracic duct
Above and below the tracheal bifurcation the lymphatics split
- up to paratracheal and cervical nodes
- down to lower mediastinal and coeliac nodes

I: para-oesophageal nodes - within para-oesophageal fatty tissue
II: mediastinal nodes - aorta, deep cervical and supraclavicular, lesser curvature, left gastric, coeliac plexus
III: peripheral nodes - lateral clavicular, pulmonary hilar, splenic hilar, greater curvature, common hepatic artery

Question 9

Phrenico-oesophageal ligament
- components (4)
- attachments
- function
- age-related changes

Answer 9

A condensation of pleura, endothoracic fascia, transversalis fascia, and peritoneum
Upper: inserts into muscular layer of lower 1-3cm of the oesophagus
Lower: inserts into cardia
- separated from GOJ by fat pad and connective tissue
Function: Airtight seal between thorax and abdomen; barrier between negative intrathoracic pressure and positive abdominal pressure
Weakening of inferior leaf with age: ligament ascends into thorax

Question 10

Crura
- origin
- structure of left and right
- sling composition

Answer 10

• 1st 4 lumbar vertebrae
• left does not divide
• right: superficial will lazily move anteromedially to join central tendon; deep will form sling around oesophagus as it enters the abdomen (oesophageal hiatus, T10)
• composition: 60% all right crus, 40% some fibres of left crus

Question 11

Nerve supply of the oesophagus

Answer 11

Parasympathetic: vagal trunks, cervical plexus, oesophageal plexi on anterior and posterior wall; small branches of CNIX and XI
Sympathetic: T4-6
Meissners plexus in submucosa
Auerbachs (myenteric) plexus between circular and longitudinal layers

Question 12

Non-iatrogenic causes of oesophageal perforation (4)

Answer 12

Caustic (early or delayed, liquefactive necrosis, NG/OGD to assess)
Foreign body (early or delayed, sharp or food bolus)
Spontaneous/Boerhaave’s (vomiting, laughing, lifting, gagging)
Traumatic (usually penetrating, surrounding structures need fixing)

Question 13

Iatrogenic causes of oesophageal perforation (7)
Who is at increased risk

Answer 13

OGD (therapeutic more likely, side viewing scopes)
EMR, ESR
Intubation
NG placement
Dilatation
Stent (delayed complications - fistulae)
Surgery (endarterectomy, thyroid, tracheostomy, thoracic and gastric surgery incl fundoplication and myotomy)

Increased risks: cervical rib, Zenkers, radiation, strictures, neoplasm

Question 14

Surgical techniques for oesophageal perforation

Answer 14

Cervical oesophagus: oblique left neck incision, retract SCM laterally and divide omohyoid and middle thyroid vein, retract trachea medially, expose with blunt dissection

Mid-thoracic oesophagus: right thoracotomy in 4-7 intercostal space, retract lung anteriorly, penrose drain to encircle oesophagus

Distal thoracic oesophagus: left posterolateral thoracotomy in 6-8 intercostal space

Abdominal oesophagus: midline laparotomy, retract left liver to right, divide short gastrics, use fundus as buttress for repair

Question 15

Presentation of oesophageal perforation according to location

Answer 15

Cervical oesophagus: left neck abscess, drooling, odynophagia
Upper and mid-thoracic oesophagus: right empyema, mediastinitis, pneumothorax
Distal thoracic oesophagus: left empyema, mediastinitis, pneumothorax; may have peritonism
Abdominal oesophagus: peritonism

Question 16

Endoscopic techniques for treatment of oesophageal perforation

Answer 16

Stent (large, can migrate if no tumour, can’t use for cervical oes)
Through the scope clips (small, mucosa only)
Over the scope clips (large diameter, full-thickness closure, can cause perf when passing)
Vacuum-assisted (for small, non-septated defects, suction of secretions and granulation, change foam every 2-3 days)

Question 17

Why place a chest drain following oesophageal repair? Where?

Answer 17

Posteriorly, next to vertebrae
To promote lung expansion, evacuate pneumothorax, prevent empyema, detect and drain any further leak
Use Blake or Jackson Pratt drain in abdomen for distal tear

Question 18

Surgical treatments for achalasia; pros and cons

Answer 18

1. Pneumatic dilatation:
   - least invasive, lasts 4 years, cost effective
   - needs redo, gets less and less effective, perforation
2. Heller myotomy
   - combined with antireflux procedure, effective, long lasting
   - surgical, risk of perf/ptx/vagal injury
3. POEM (peroral endoscopic myotomy)
   - cut fibres of LOS to cardia submucosally; less invasive, good for type III (spasmodic) achalasia
   - risk of perforation, no anti-reflux procedure

Question 19

What is the pathophysiology of achalasia?

Answer 19

Achalasia is an oesophageal motility disorder characterised by dysphagia to solids and liquids, regurgitation and symptoms of GORD
Due to hypertension of the LOS and aperistaltic distal oesophagus
Thought to be neurodegenerative, arising from an auto-immune process attacking the myenteric ganglia within the muscular wall of the oesophagus

Question 20

Sclerosant of choice for treatment of oesophageal varices

Answer 20

5% ethanolamine oleate

Question 21

Treatment of oesophageal varices (steps) (10)

Answer 21

Resuscitation: IVL, fluids, blood/clotting factors
Intubation
NG tube
Erythromycin: prokinetic
Ceftriaxone: antibiotic
Terlipressin: vasopressin analogue, causes mesenteric constriction and decrease in portal blood flow
Balloon tamponade (a step toward definitive management)
Endoscopy: band ligation or sclerotherapy
TIPS
Portocaval/surgical shunt
Liver transplant

Question 22

Los Angeles classification of reflux oesophagitis

Answer 22

LA grade A: one or more mucosal breaks, <5mm length

LA grade B: one or more mucosal breaks, >5mm but not continuous over mucosal folds
LA grade C: at least one break continuous over the mucosal fold but not more than 75% circumference
LA grade D: mucosal break involving >75% circumference

Question 23

What is the pathophysiology by which Barretts oesophagus transforms from metaplasia to adenocarcinoma?

Answer 23

40% through traditional pathway of gradual sequence of genetic alterations associated with dysplastic changes of increasing severity

60% through chromosomal instability in Barretts metaplastic cells - allow cancer to develop rapidly (even between surveillance intervals) - genomic doubling

Question 24

Adenocarcinoma incidence in patients with Barretts

Answer 24

0.1-3% of those with Barretts have adenocarcinoma
30-fold risk above general population
Barretts patients often die of non-cancer related causes (obesity, cardiac, age)

Question 25

What are the basic principles of antireflux surgery?

Answer 25

Restoration of effective lower oesophageal sphincter
Creation of a gastro-oesophageal valve

Plication of fundus around oesophagus due to physiologic relaxation of fundus with relaxation of LOS following swallow
Fundoplication resides in the stomach without tension
Crura are closed to prevent migration of stomach into chest

Question 26

What is oesophageal reflux?

Answer 26

A syndrome where the reflux of stomach contents causes symptoms and/or complications (Montral consensus)

Question 27

What is the pathophysiology of acid reflux in hiatus hernia?

Answer 27

Loss of the structural protective mechanisms of the lower oesophageal sphincter
- phrenico-oesophageal ligament
- angle of His
- widening of crura so no pinchcock mechanism
- loss of sling fibres of lower oesophagus

Question 28

What is plummer vinson syndrome?

Answer 28

Rare condition characterised by triad of dysphagia (progressive), iron defiency and oesophageal webs

Predisposes to upper oesophageal SCC