Anatomy of Gastroesophageal Junction with special reference to hiatus hernia and anatomical basis of therapeutic intervention

Dr. Rana Pratap Singh JRII Surgery M.L.B. Medical College, Jhansi

Introduction

• From mouth to stomach, the food conduit consists of the oral cavity, pharynx, and esophagus.

• The esophagus serves as a dynamic tube, pushing food toward the stomach.

• Active peristaltic contractions propel residual material from the esophagus into the stomach.

Anatomical Division

The esophagus is a midline structure lying on the anterior surface of the spine.

It descends through three compartments: the neck, the chest, and the abdomen.

This progression has led to its classic anatomic division into cervical, thoracic, and abdominal segments.

Two new subdivisions One is functional aspects and makes a distinction

between the esophageal body and the upper and lower sphincters.

The other is oncosurgery aspects and distinguishes between the proximal and the distal esophagus, with the tracheal bifurcation used as dividing part.

Constrictions of esophagus

• It is the narrowest part of the alimentary tract (except for the vermiform appendix).

• 1. at the beginning (15 cm from the incisor teeth), • 2.crossed by the aortic arch (22.5 cm from the incisor teeth)

• 3. crossed by the left bronchus (27.5 cm from the incisors)

• 4. as it passes through the diaphragm (40 cm from the incisors).

• These are important clinically with regard to the passage of instruments .

Cervical esophagus

• approximately 5 cm long

• descends between the trachea and the vertebral

column.

• C6 to the level of the interspace between the T1 and

T2 vert posteriorly, and suprasternal notch

anteriorly.

Thoracic esophagus

• approximately 20 cm long.• It starts at the thoracic inlet. • In thorax, it is in close relationship

with the posterior wall of the trachea and the prevertebral fascia.

• Just above the tracheal bifurcation, the esophagus passes to the right of the aorta. This anatomic positioning can cause a notch indentation in its left lateral wall on a barium swallow radiogram.

abdominal esophagus

• 2 cm long and includes a portion of the lower esophageal sphincter (LES) .

• It starts as the esophagus passes through the diaphragmatic hiatus and is surrounded by the phrenoesophageal membrane.

• The musculature divided into an outer longitudinal and an inner circular layer.

• The upper 2 to 6 cm of the esophagus contains only striated muscle fibers. From there on, smooth muscle fibers gradually become more abundant.

Arterial supply

• Cervical Oesophagus: Right & Left superior & inferior thyroid arteries.

• Thoracic Oesophagus: Up to tracheal bifurcation Right & Left inferior thyroid Artery

direct supply from aorta (tracheo-bronchial tree)• Abdominal Oesophagus: ascending branch of the left

gastric artery and from inferior phrenic arteries

Gastroesophageal Junction

• 4 anatomical points that identify the gastroesophageal junction (GEJ): two endoscopic and two external.

• Endoscopically- 1. The squamocolumnar epithelial junction (Z-line)

may mark the GEJ provided the patient does not have a distal esophagus replaced by columnar-lined epithelium as seen with Barrett's esophagus.

2. The transition from the smooth esophageal lining to the rugal folds of the stomach.

• Externally- 1.the collar of Helvetius (or loop of Willis)- where the circular muscular fibers of the

esophagus join the oblique fibers of the stomach

2.the gastroesophageal fat pad

• Two to three centimeters above the hiatus of

the diaphragm it is anchored at its lower end by the insertion of a tough, skirt-like prolongation of the endoabdominal fascia from the undersurface of the diaphragm, the ascending leaf of the phrenoesophageal ligament.

• 2 to 5cm below the insertion of the phrenoesophageal ligament. squamous changes to columnar epithelium.

• The point of transition is marked by ora serrata or "z" line

• Two cm of the esophagus immediately above the epithelial junction are contained within the sling of the right diaphragmatic crus as it forms the hiatus.

PHRENOESOPHAGEAL LIGAMENTS

• The phrenoesophageal ligament arises primarily from the endoabdominal fascia.

• At the lower margin of the esophageal hiatus, it decussates into an upper and a lower leaf.

• The upper leaf extends through the hiatus to insert into the esophagus two to three centimeters above it.

• The lower leaf, which exists as a loosely defined collection of fibroelastic fibers, descends to insert into the esophagus at or below the epithelial junction.

• The upper leaf is strong, well-defined membrane rather than a ligament

Diaphragm and esophageal hiatus viewed from the abdominal aspect.

• Physiology– It has been shown by manometric

techniques that a sphincteric mechanism exists at the gastroesophageal junction.

– This barrier we refer to as the lower esophageal sphincter.

• Two conditions under which the gastroesophageal junction must maintain competence.

1. First is at rest 2. Second raised intra abdominal pressure.

At rest the sphincter normally maintains a pressure barrier between positive intra gastric and negative intrathoracic pressure.

This pressure differential is approximately 10 cm. H2O .

It is present in all phases of respiration and may be maintained even when the GE junction is displaced into the thorax, as in sliding hernia.

• Raised intra abdominal pressure. The phrenoesophageal ligament maintains the

esophagogastric junction within the abdomen, and the increased intraabdominal pressure is brought equally to bear on the abdominal esophagus containing a portion of the sphincter as well as on the stomach.

• The sphincter, reinforced by this pressure, is able to maintain a pressure differential between the stomach and thoracic esophagus.

• Pathophysiology– In hiatal hernia of the sliding type, the clinical

manifestations are due to gastroesophageal reflux. – hiatal hernia may exist and even attain mammoth

proportions without reflux. – The mechanism which can prevent reflux under

these conditions is the sphincter .

• What then leads to the development of gastroesophageal reflux?– The answer is that the gastroesophageal sphincter

has become incompetent.

• The normal tension on theA. Normally, the ascending limb

of the phrenoesophageal ligament inserts into the esophageal wall above the lower esophageal sphincter mechanism. Forces applied to the ligament by the contracting diaphragmatic musculature serve only to dilate the esophagus above the sphincter. This may be the origin of the radiologically familiar "Phrenic Ampulla."

B. If the ligamentous insertion were to be displaced inferiorly, then tension transmitted through the ligament would serve to dilate the sphincter itself, allowing gastroesophageal reflux to to occur.

C. The same situation would pertain in the patient with a sliding hiatal hernia. Normally, in the hiatal hernia patient without reflux, the ligament would insert above the sphincter area, producing the classic three radiologic criteria of hiatal hernia: The phrenic ampulla, the esophageal vestibule (corresponding to the sphincter area which has been displaced above the diaphragm), and the supra-diaphragmatic gastric loculus.

D. If the ligamentous insertion were to be displaced inferiorly, reflux would ensue. If the patient still possessed a competent sphincter, any operation which would reduce tension on the ligaments would cure the reflux.

Esophageal tissues

Wall structure at the esophagogastric junction. The tunica muscularis is composed of both a longitudinal (2a) and a circular layer (2b). a, muscularis mucosae; b, lamina propria; c, epithelium; G1, esophageal glands; G2, gastric glands; Ly,lymph vessels; N1, myenteric plexus; N2, submucous nerve plexus.

GIANT DIAPHRAGMATIC (HIATAL) HERNIAS

A. The sliding hernia, type I, characterized by an upward dislocation of the cardia in the posterior mediastinum.

B. The rolling or PEH, type II, characterized by an upward dislocation of the gastric fundus alongside a normally positioned cardia.

C. The combined sliding-rolling or mixed hernia, type III, characterized by an upward dislocation of boththe cardia and the gastric fundus

D. In some taxonomies, a type IV hiatal hernia is declared when an additional organ, usually the colon, herniates as well

• incidence of a sliding hiatal hernia is seven times higher than that of a PEH. The PEH is also known as the giant hiatal hernia.

• The median age of the PEHs is 61 years old; of the sliding hiatal, 48 years old. PEHs are more likely to occur in women by a ratio of 4:1.

Clinical Manifestations

• The clinical presentation of a giant hiatal (paraesophageal) hernia differs from that of a sliding hernia.

• symptoms of dysphagia and postprandial fullness with PEHs, but the typical symptoms of heartburn and regurgitation present in sliding hiatal hernias can also occur.

Diagnosis1. A radiogram of the chest with the

patient in the upright position can diagnose a hiatal hernia if it shows an air-fluid level behind the cardiac shadow.

2. Fiber-optic esophagoscopy is useful in the diagnosis and classification of a hiatal hernia because the scope can be retroflexed.

• Sliding hiatal hernia can be identified by 1. Rugal folds extending above the

impression caused by the crura of the diaphragm.

2. Measuring at least 2 cm between the crura and the squamocolumnar junction.

• PEH is identified on retroversion of the scope by noting a separate orifice adjacent to the GEJ into which gastric rugal folds ascend.

Treatment

A. Indications for repairB. Surgical approachC. Role of fundoplication

INDICATIONS & SURGICAL APPROACH

• This recommendation is based upon two clinical observations.

• First, retrospective studies have shown a significant incidence of life-threatening complications of bleeding, infarction, and perforation in patients being followed with known paraesophageal herniation.

• Second, emergency repair carries a high mortality.

• If surgery is delayed and repair is done on an emergency basis, operative mortality is high, compared to <1% for an elective repair

SURGICAL APPROACH• A transthoracic approach facilitates complete

esophageal mobilization but is rarely used because the access trauma and postoperative pain are significantly greater than a laparoscopic approach.

The transabdominal approach facilitates reduction of the volvulus that is often associated with PEHs.

Although some degree of esophageal mobilization can be accomplished transhiatally, complete mobilization to the aortic arch is difficult or impossible without risk of injury to the vagal nerves.

ROLE OF FUNDOPLICATION IN HIATAL HERNIA REPAIR

• Most advocate the routine addition of an antireflux procedure following repair of the hernia defect.

• The main reasons for this. 1. Physiologic testing with 24-hour esophageal pH

monitoring has shown increased esophageal exposure to gastric juice in 60 to 70% of patients with a PEHs,

2.71% incidence in patients with a sliding hiatal hernia

PREOPERATIVE EVALUATION

1. First, the propulsive force of the body of the esophagus should be evaluated by esophageal manometry to determine if it has sufficient power to propel a bolus of food through a newly reconstructed valve.

• Patients with normal peristaltic contractions do well with a 360° Nissen fundoplication.

• When peristalsis is absent a partialfundoplication may be the procedure of choice, but only if achalasia has been ruled out.

2. Second, shortening of the esophagus can compromise the ability to do an adequate repair without tension, and lead to an increased incidence of breakdown or thoracic displacement of the repair.

• Esophageal shortening is identified on a barium swallow roentgenogram by a sliding hiatal hernia that will not reduce in the upright position, or that measures larger than 5 cm between the diaphragmatic crura and GEJ on endoscopy.

PRINCIPLES OF SURGICAL THERAPY

• Operation should restore the LES pressure twice the resting gastric pressure. • The length of the intraabdominal

oesophagus should be maintained 2 or more cm.• Apposition of diaphragmatic crurae,

reduction of hiatus hernia done when present.

• Repaired OG junction should relax during swallowing adequately. To ensure this only fundus of the stomach should be used to buttress the sphincter and avoid damage to vagal nerve.

• Tension free short and flopy fundoplication should be done.

Fundoplications

• Nissen’s – total 3600 posterior fundoplication. • Toupet’s – partial 1800 posterior fundal.• Dor – anterior partial. • Rosetti Hell – total anterior fundal• Watson’s – anterolateral 1200 partial.• Lind – posterior and anterior

a. Laparoscopic Nissen fundoplication is performed with a five-trocar technique.

b. The liver retractor is affixed to a mechanical arm to hold it in place throughout the operation.

c. After division of the gastrohepatic omentum above the hepatic branch of the vagus (pars flaccida), the surgeon places a blunt atraumatic grasper beneath the phrenoesophageal ligament.

d. After completion of the crural closure, an atraumatic grasper is placed right to left behind the gastroesophageal junction. The grasper is withdrawn, pulling the posterior aspect of the gastric fundus behind the esophagus

e. Once the suture positions are chosen, the first stitch (2-0 silk, 20 cm long) is introduced through the 10-mm trocar, and the needle is passed first through the left limb of the fundus, then the esophagus (2.5 cm above the gastroesophageal junction), then through the right limb of the fundus.

f. Final position of the fundoplication

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