Pathophysiology of Gastroesophageal Reflux Disease and Hiatal Hernia

Sandro Mattioli, Marialuisa Lugaresi, Niccolò Daddi

Key Points

  • Transient lower esophageal sphincter relaxation (TLESR) is a dominant mechanism of lower esophageal sphincter (LES) dysfunction leading to gastro-esophageal reflux disease (GERD). Other mechanisms of GERD include a hypotensive lower esophageal sphincter (LES), and anatomic disruption of the gastroesophageal junction.
  • Delayed esophageal acid clearance is also an important factor in the development of reflux esophagitis.
  • Increased compliance (relaxation and distension capacity) of the esophago-gastric (E-G) junction contributes to incompetence of the gastroesophageal junction, because it decreases the resistance to flow across the E-G junction.
  • In the postprandial period, gastro-esophageal reflux (GER) originates from an “acid pocket” that forms as a consequence of the pooling of newly secreted acid in the proximal portion of the stomach above ingested chyme. Hiatal hernia (HH) contributes to the formation, size, and position of the acid pocket.
  • Axial HHs, characterized by the permanent supra-diaphragmatic migration of the E-G junction contribute to the impairment of cardia continence. Hiatal insufficiency, concentric HH, and short esophagus are signs of migration. These radiological/anatomical conditions are generally associated with severe, persistent GERD. The distance between the E-G junction and the diaphragm, not the size of hernia, influences the degree of cardiac incontinence and the severity of GERD.
  • The influence of HH on the clinical presentation of GERD, according to various pathophysiological mechanisms, must be carefully investigated. When a HH is partially or predominately responsible of severe and persistent GERD, it is reasonable to consider surgery to resolve an anatomic cause of GERD.
  • While pathophysiological studies refer generally to HH, the surgical literature tends to distinguish between axial HH (reducible or non-reducible) and non-axial HH in consideration of the different clinical and pathophysiological characters of different types of HH and of the necessity to tailor the surgical technique according to the anatomy of hernia and diaphragmatic hiatus.
  • The barium swallow is still essential to evaluate the morphology/anatomy of the upper gastro-intestinal tract, in the upright and supine positions. Barium swallow study is useful to define the indication for surgical therapy, to choose the appropriate technique, to provide the patient obligatory information regarding the type of operation he or she will undergo, and to anticipate possible complications and expected results of the surgical procedure. In particular, the following characteristics must be assessed:
    • The type of gastric HH—axial (sliding, hiatal insufficiency, concentric HH, short esophagus) or non-axial (paraesophageal or massively intrathoracic).
    • If the E-G junction is fixed in an upright position above the diaphragm—for which an esophageal-lengthening procedure, like the Collis gastroplasty, may be necessary, if a condition of true short esophagus is determined intraoperatively.

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Last updated: June 29, 2023