esophagus

THE OESOPHAGUS

Dr. D.W. DaughertyDepartment of Surgery

AnatomyI. Pharyngoesophageal Segment

The segment between the laryngopharynx and the cervical esophagus.

Includes the superior, middle, and inferior constrictors.

Ends at the cricopharyngeal muscle (which is where the cervial esophagus begins).

AnatomyII. Cervical Esophagus

Begins below the cricopharyngeus muscle.

The cricopharyngeus muscle is continuous with the more superior inferior constrictor of the pharyngoesophagus.

* It is the potential space between these muscles that is the site where Zenker’s diverticulum develops.


Approximately 5cm in length and begins at C-6 and extends to T-1.

Anteriorly, lie the trachea and the lobes of the thyroid.

Posteriorly is the retropharyngeal space.

Laterally are the carotid sheaths.


The recurrent laryngeal nerves lie in grooves between the esophagus and trachea.

The right recurrent laryngeal nerve runs an oblique course and is most prone to anatomic variation.

* Incisional approach from the left side of the neck, along the anterior border of the SCM muscle, is chosen if possible.

AnatomyIII. Thoracic Esophagus

Above the level of the tracheal bifurcation, the esophagus courses to the right of the descending aorta and is in close relation to the posterior tracheal wall.

It then courses left, behind the tracheal bifurcation and left main bronchus.

The lower third then courses anteriorly and to the left to pass through the diaphragmatic hiatus at the level of T-10.

AnatomyIII. Thoracic Esophagus

The lower esophagus is covered only by the flimsy mediastinal pleura on the left. This is the weakest portion and is most commonly the site of perforation in Boerhaave’s syndrome.

* Boerhaave’s syndrome: increased intra-esophageal pressure secondary to emesis or retching ultimately leading to a rupture/perforation.

AnatomyIV.Abdominal Esophagus

Begins where the esophagus enters the abdomen through the diaphragmatic hiatus, at T-10.

It is surrounded by a fibroelastic membrane, the phrenoesophageal ligament, which arises from the sub-diaphragmatic fascia.

The lower limit of the phrenoesophageal ligament anteriorly is marked by a prominent fat pad, which corresponds to the gastro-esophageal junction.

AnatomyThe Lower Esophageal Sphincter (LES)

Zone of high pressure measuring 3-5 cm long at the lower end of the esophagus.

The LES is a physiologic sphincter. NOT an anatomic sphincter. Therefore, it does not correspond to any gross anatomical structure.

* Incompetence of this physiologic sphincter results in gastro-esohpageal reflux disease (GERD) and could unltimately lead to Barrett’s esophagitis.

AnatomyHistology

The wall is composed of two muscular layers. - Inner Circular and Outer Longitudinal

Upper 2/3 is striated muscleLower 1/3 is smooth muscle

No surrounding Serosal covering

Prominent Submucosa

AnatomyHistology

The mucosal Lining is made up of squamous epithelium

Exception is the distal 1-3 cm of the esophagus, which are composed of columnar epithelium

** Barrett’s esophagous the metaplasia of the esophageal squamous epithelium to columnar epithelium.

It is a result of severe reflux disease and is a risk factor for esophageal adenocarcinoma.

AnatomyArterial Supply

Cervical Esophagus: The Inferior Thyroid Arteries Thoracic Esophagus:

Proximal: Branches from two or three bronchial Arteries

Distal: Branches directly from the Aorta. The most proximal arise between the 6th and 7th thoracic vertebrae; the most distal arise between the 8th and 9th vertebrae

AnatomyArterial Supply

Abdominal Esophagus: Branches of the Left Gastric ArteryBranches of the Inferior Phrenic Artery

Intramuscular:

Once the vessels have entered the muscular wall of the esophagus, branching occurs at right angles to provide a longitudinal plexus

* Important in that this allows mobilization of the esophagus without ischemic injury

AnatomyVenous Drainage

Extensive venous plexus in the submucosa

Then drains to into the peri-esophageal plexus

Proximal 1/3: drains to the inferior thyroid vein

Middle 1/3: drains into the bronchial, azygos, or hemiazygos veins in the thorax

AnatomyVenous Drainage

Distal 1/3: drains into the left gastric vein or

coronary vein. This provides the principle collateral circulation to the portal system.

* Esophageal verices develop in these vessels secondary to increased portal pressure in portal hypertension.

** Submucosal veins in the distal 1-2 cm of

the esophagus become very superficial and are consequently the most common site of bleeding in portal hypertension.

AnatomyLymphatics

Upper 2/3 of Esophagus:

Cervical esophagus drains to the internal

jugular nodes

Dorsal Thoracic esophagus drains to the posterior mediastinal nodes

Anterior Thoracic esophagus drains to the

tracheal nodes superiorly and subcarinal and paraesophageal nodes inferiorly

AnatomyLymphatics

Lower 2/3 of Esophagus:

Abdominal esophagus drains to the cardiac and celiac nodes

Eventually, this drains to the cisterna chyli or the thoracic

AnatomyLymphatics

Cancer – Lymphatic Spread

Tumor limited to the mucosa: the incidence of lymphatic spread is low.

Tumor invades the submucosa: the incidence of nodal metastasis is 60% due to the rich

submucosal lymphatics

A three field lymph node dissection provides the best evidence for staging

AnatomyInnervation

Right and left recurrent laryngeal nerves, arising from the Vagus (X), provide the innervation to the cricopharyngeal sphincter and cervical portion of the esophagus

* Injury to one or both of these nerves results in vocal cord dysfunction, cricopharyngeal dysfunction, motility dysfunction, and inability to properly close the glottis.

** These dysfunctions all contribute to the risk of aspiration.

AnatomyInnervation

The esophageal plexus on the anterior and posterior walls of the esophagus innervate the lower esophagus.

This plexus also receives fibers from the thoracic sympathetic chain.

The single trunks distally contain fibers from both the original vagus nerves

AnatomyInnervationEfferents:

Preganglionic sympathetic fibers arise from the spinal segments 4-6

Terminate in the cervical and thoracic sympathetic ganglia

Postganglionic fibers reach the esophagus from the cervical and thoracic sympathetic chain

Distal esophagus receives sympathetic fibers directly from the celiac ganglion

AnatomyInnervationAfferents:

Visceral sensory pain fibers from the esophagus terminate without synapses in segments 1-4 of the thoracic cord

Follows both sympathetic and vagal pathways

* Vagal fibers from the heart also travel in the same pathway, explaining the similarity of symptoms in many esophageal and cardiac diseases

Physiology – Swallowing

• Food bolus enters the esophagus and the cricopharyngeus muscle constricts causing an increase in pressure to 60mmHg (twice the resting pressure of 30mmHg)

• Smooth muscle activation is initiated and a peristaltic wave is generated.

• A pressure gradient of 10mmHg exists between the thorax and abdomen. This is overcome by peristaltic pressure.

• The Lower Esophageal Sphincter (LES) relaxes and allows the bolus to be passed to the stomach.

Physiology – LES

• Provides the pressure barrier between the esophagus and the stomach.

• A physiologic sphincter, not an anatomic sphincter.

• Is an area approximately 3-5cm in length and normal resting pressures range from 10-20 mm Hg.

• Has intrinsic myogenic tone, modulated by neural and hormonal mechanisms.

• The vagus nerve carries both excitatory and inhibitory fibers to the esophagus and the LES.

Physiology – LES

• Increase LES pressure: Gastrin, Motilin, Beta-blockers, Alpha- adrenergic agonists, Antacids, Cholinergics, Metocloprimide.

• Decrease LES pressure: Cholecystokinin, Estrogen, Glucagon, Progesterone, Secretin, Anti-cholinergics, Barbituates, Ca-Channel blockers, Diazepam, Meperidine.

• Dietary contribution to decreased LES tone: Caffiene, Coffee, Alcohol, Peppermint, Chocolate, and Fat.

• LES pressures of less than 6 mm Hg (equal to that of intra-abdominal pressure) or a length of less than 2cm are associated with LES incompetence and GERD.

Evaluation of the Esophagus

• Endoscopy

• CT Scan

• Barium Swallow

• Endoscopic Ultrasound (EUS)

• Manometry

• pH Monitoring

Motility Disorders

• Four Categories: • Inadequate relaxation of the LES – Achalasia

• Uncoordinated contractions – Diffuse Esophageal Spasm (DES)

• Hypercontraction – Nutcracker esophagus

•Hypocontraction – Ineffective motility

Esophageal Diverticula

• Pulsion Diverticula

• Traction Diverticula

• Pharyngoesophageal (Zenker) Diverticulum

Esophageal Perforation

Esophageal Caustic Injury

Esophageal Reflux Disease


• Barrett’s Esophagitis

Metaplasia of the squamous cells in the lower esophageal lining to columnar cells

Caused by chronic GERD

Predisposing condition for dysplasia and thus transformation into esophageal adenocarcinoma

Esophageal Cancer

• Risk Factors:

- Tobacco use- Heavy alcohol use- Barretts esophagitis- Age- Men- Race: African-Americans, Asians

Esophageal Cancer

• Symptoms:

- Dysphagia- Odynophagia - Weight loss - Sub-sternal chest pain - Hoarseness - Cough - Indigestion / Heartburn

Esophageal Cancer

• Work Up

- Bronchoscopy- Laryngoscopy- Endoscopic Ultrasound- CT Scan- PET Scan

Esophageal Cancer

• Squamous cell carcinoma: Most often found in the upper and middle part of the esophagus, but can occur anywhere along the esophagus. This is also called epidermoid carcinoma.

Associated with smoking and alcohol use.

• Adenocarcinoma: Most often form in the lower part of the esophagus, near the stomach.

Associated with Barrett’s esophagitis.

Esophageal Cancer

Esophageal Cancer - Treatment

Esophageal Cancer - Survival

Esophageal Cancer - Esophagectomy

Esophageal Stenting