Gastroesophageal reflux is a common disease in children, and when conservative medical treatment is ineffective, reflux can be effectively controlled by surgical procedures. However, postoperative complications are more common; therefore, an understanding of gastroesophageal physiology is necessary to screen surgical cases and manage postoperative complications.
Physiology of the gastroesophageal junction
The lower esophageal sphincter and the right diaphragm angle play an important role in the control of reflux at the gastroesophageal junction. At rest, the lower esophageal sphincter maintains a pressure of 10-30 mmHg above the intragastric pressure, and when the intragastric pressure increases, the lower esophageal sphincter pressure increases accordingly. When swallowing, eructation and vomiting are present, the lower esophageal sphincter pressure reflexively decreases. The right diaphragm angle wraps around the distal esophagus and acts as a clamp around the lower esophageal sphincter. When gastric resting pressure increases during inspiration or when other factors cause an increase in intragastric pressure (e.g., coughing) the diaphragmatic angle contracts to close the lower esophagus. Reflex relaxation of the diaphragm angle is often accompanied by a sluggish lower esophageal sphincter.
Mechanism of gastroesophageal reflux
Gastroesophageal reflux is the reflux of gastric contents into the esophagus. The mechanism is a decrease in the anti-reflux function of the esophagus or a breakdown of the anti-reflux barrier. Gastroesophageal reflux that occurs in normal individuals is not usually consequential. When reflux causes significant symptoms or damage to the individual, it is called GERD. The progression of reflux depends on the balance between reflux-promoting factors and the ability of the esophagus to clear and resist gastric acid-protease. One of the major factors in the development of GERD is dysfunction of the lower esophageal sphincter.
The most common mechanism by which reflux occurs is the phenomenon of “transient relaxation” of the lower esophageal sphincter: reflux occurs suddenly when the lower esophageal sphincter has a normal basal pressure, but is accompanied by a transient decrease in pressure near zero level, which is not caused by a swallowing action. The “transient relaxation” phenomenon can occur in asymptomatic individuals, but it occurs frequently in GERD and constitutes the bulk of reflux. The transient relaxation of the lower esophageal sphincter is caused by the vagal reflex; it is the result of gastric dilatation stimulating mechanoreceptors distributed in the fundus of the stomach, especially around the cardia. The physiological manifestation of this transient relaxation is hiccups, which occur when the diaphragm angle is completely relaxed. Secondly, reflux occurs when the lower esophageal sphincter base pressure decreases.
Other factors causing GERD include local anatomical abnormalities such as sliding esophageal hiatal hernia, which separates the lower esophageal sphincter from the diaphragmatic angle. In addition, esophageal malfunction, delayed gastric emptying, elevated intra-abdominal pressure, central nervous system injury, and gastrostomy can contribute to the development of GERD.
Internal treatment of GERD
Most children with GERD are treated internally with
1. Small meals or nutrition via nasal cannula to reduce refluxed food and decrease the frequency of lower esophageal relaxation.
2. Viscous diet to reduce the extent of fluid reflux.
3.Upright position to reduce reflux and promote esophageal emptying by gravity.
4.Apply antacids, histamine receptor blockers or proton pump inhibitors to reduce the acidity of the refluxed material.
5.Gastric motility drugs are given to promote gastric emptying and esophageal peristalsis as well as to enhance lower esophageal sphincter function.
Surgical treatment of GERD
Surgical treatment is indicated in cases where symptoms are difficult to control with systemic medical therapy and in the presence of serious complications such as severe esophageal ulcer, Barrett’s esophagus or stricture, chronic lung disease or recurrent aspiration pneumonia, or acute life-threatening conditions. For example, persistent growth disturbances despite aggressive medical treatment. Children with normal neurodevelopment tend to improve as they get older. If symptoms can be controlled with medical therapy, they should be treated conservatively. Children with GERD who have combined central nervous system damage are more likely to require surgical treatment. The authors advocate the Niseen fundoplication procedure, which can be performed with a gastrostomy or simply with a fundoplication.
Diagnosis
The most common symptom of GERD in children is reflux of food into the esophagus or vomiting. Esophagitis can cause pain or acute or chronic bleeding, which can lead to esophageal stricture and dysphagia. Respiratory symptoms include reflux asthma, acute respiratory distress syndrome and recurrent aspiration pneumonia, as well as chronic lung disorders.
The above symptoms caused by GERD may also be caused by other causes and are therefore not specific. If the child is effective with simple anti-reflux therapy, further invasive testing may not be necessary. However, in cases where surgical intervention is required, tests should be performed to determine if the above symptoms are due to reflux, if possible. The physician should take a detailed history, the number of vomits and the amount of vomiting, and pay attention to the signs of hyperemetic reflex such as pale face, salivation, sweating or eructation that accompany vomiting. The authors intend to plan objective tests for gastroesophageal reflux to determine the severity of reflux, potential etiology and complications. The main tests are as follows.
1. Barium swallow imaging of the esophagus For determining the presence of anatomical abnormalities or causes of obstruction (such as esophageal stricture, poor midgut rotation, or duodenal membranous stricture). Gastroesophageal reflux can be detected during the imaging procedure, but some reflux may be missed due to the short observation time. In addition, in children with hyperemetic reflex, strong vomiting and eructation return the contrast agent to the esophagus, which can easily be considered as GERD, or misdiagnosed as esophageal hiatal hernia if accompanied by an upward shift of the gastroesophageal junction. Therefore, gastroesophageal reflux surgery cannot be based on radiological examination alone.
2. 24-hour esophageal pH test is a sensitive tool for diagnosing GERD and can quantitatively evaluate the degree of reflux. Reflux also occurs daily in normal individuals. Surgical procedures for pH monitoring are moderate reflux.