The relationship between hiatal hernias and gastroesophageal reflux disease (GERD) has been greatly debated over the past decades, with the importance of hiatal hernias first being overemphasized and then later being nearly neglected. It is now understood that both the anatomical (hiatal hernia) and the physiological (lower esophageal sphincter) features of the gastroesophageal junction play important, but independent, roles in the pathogenesis of GERD, constituting the widely accepted "two-sphincter hypothesis." The gastroesophageal junction is an anatomically complex area with an inherent antireflux barrier function. However, the gastroesophageal junction becomes incompetent and esophageal acid clearance is compromised in patients with hiatal hernia, which facilitates the development of GERD. Of the different types of hiatal hernias (types I, II, III, and IV), type I (sliding) hiatal hernias are closely associated with GERD. Because GERD may lead to reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma, a better understanding of this association is warranted. Hiatal hernias can be diagnosed radiographically, endoscopically or manometrically, with each modality having its own limitations, especially in the diagnosis of hiatal hernias less than 2 cm in length. In the future, high resolution manometry should be a promising method for accurately assessing the association between hiatal hernias and GERD. The treatment of a hiatal hernia is similar to the management of GERD and should be reserved for those with symptoms attributable to this condition. Surgery should be considered for those patients with refractory symptoms and for those who develop complications, such as recurrent bleeding, ulcerations or strictures.
Keywords: Gastroesophageal reflux disease; Hiatal hernia; Lower esophageal sphincter.