Gastroesophageal Reflux

Gastroesophageal Reflux Disease (GERD)

1. Pathophysiology
1. Lower Esophageal Sphincter (LES) Physiology
• not a distinct anatomic structure, but rather a high pressure zone
• muscles of the distal esophagus are tonically contracted, and relax when a swallow is initiated
• sling fibers of the gastric cardia, which are at the same depth as the circular muscle fibers of the esophagus but are oriented in a different direction, also contributes to the esophageal high-pressure zone
• the diaphragm contributes to LES pressure by compressing the esophagus when it contracts
• positive intraabdominal pressure also contributes to LES pressure



2. Decreased LES Pressure
1. Transient Loss of LES Pressure
• LES is structurally normal
• responsible for ‘physiologic’ reflux
• results from gastric distention secondary to overeating, stress aerophagia, delayed gastric emptying, increased intragastric or increased intraabdominal pressure
• gastric distention pulls open the LES and reduces its overall length
• when a critical length is reached, between 1 and 2 cm, LES pressure drops markedly and reflux occurs
• after gastric venting occurs, sphincter length is restored and competence returns until further distention again shortens the LES


2. Permanent Loss of LES Pressure
• results from structural damage to the components of the LES: loss of pressure, inadequate overall length, or loss of abdominal length
• reduced LES pressure is most likely due to an abnormality of myogenic function (length and tension properties of the LES’s smooth muscle)
• the efficacy of a LES with normal pressure can be nullified by an inadequate abdominal length or overall length
• an adequate abdominal length is important in preventing reflux caused by increases in intraabdominal pressure (exertion or changes in body position)
• an adequate overall length is important in preventing reflux caused by gastric distention


3. Ineffective Esophageal Clearance
• an effective esophageal pump clears the esophagus of physiologic reflux
• four factors are important in esophageal clearance of gastric juice: gravity, esophageal motor activity, salivation, and anchoring of the distal esophagus in the abdomen (hiatal hernia)
• ineffective esophageal clearance is usually seen in association with a structurally defective LES, which augments the esophageal exposure to gastric juice by prolonging the duration of each reflux episode


4. Hiatal Hernia
• sliding (type I) is the most common hiatal hernia associated with reflux
• occurs when the phrenoesophageal ligament does not maintain the GEJ in the abdominal cavity
• there is a strong association between GERD and hiatal hernia: most patients with GERD have a hiatal hernia, and the larger the hernia the greater the amount of acid reflux
• however, not every patient with reflux has a hiatal hernia; and not every patient with a hiatal hernia has reflux



2. Clinical Presentation
1. Symptoms
• most common symptoms are substernal heartburn (early) and acid regurgitation (late)
• however, these symptoms are very common in the general population and may be caused by many other diseases besides GERD
• also, GERD may present with atypical symptoms such as nausea, vomiting, postprandial fullness, chest pain, chronic cough, wheezing, asthma, or recurrent pneumonia
• using clinical criteria alone to define GERD lacks sensitivity and specificity
• to make the diagnosis of GERD, objective evidence is required (endoscopy, pH probe, Barrett’s esophagus)


2. Complications of GERD
1. Esophagitis
• repeated injury and repair leads to fibrosis and progressive deterioration of esophageal contractility
• stricture and Barrett’s esophagus are the end stages of chronic esophagitis



2. Stricture
• most common symptom is dysphagia
• need to rule out tumor, motor disorder, diverticula



3. Barrett’s Esophagus
• defined as the pathological replacement of the esophagus’ normal stratified squamous epithelium with an intestinal-like columnar epithelium (intestinal metaplasia)
• caused by chronic esophageal injury and inflammation
• represents an increased risk of developing esophageal adenocarcinoma (0.5% per year)



4. Aspiration
• refluxed gastric juice can reach the pharynx
• symptoms include repetitive cough, choking, hoarseness, and recurrent pneumonia
• GERD may be responsible for pulmonary diseases such as asthma, pulmonary fibrosis, and bronchiectasis


3. Treatment of GERD
1. Empiric Medical Management
• patients with symptoms of heartburn without obvious complications can be given a 6 week trial of a proton pump inhibitor (PPI) without further studies
• additional lifestyle interventions include elevating the head of the bed, avoiding tight clothing, eating small, frequent meals, avoiding eating shortly before bed, losing weight, and avoiding alcohol, coffee and chocolate
• most patients (80%) have a recurrence of GERD after discontinuation of any type of medical therapy
• long-term complications of PPIs are being studied: nutritional deficiencies, infectious complications, gastric polyp formation, osteoporosis


2. Evaluation
• required for all patients being considered for surgery, as well as for patients with atypical symptoms or possible complications


1. Endoscopy
• very high specificity for diagnosing GERD, but lacks sensitivity – about 50% of GERD patients have normal endoscopic findings
• severity of symptoms correlates poorly with the severity of esophagitis
• most useful for detecting complications of GERD (erosive esophagitis, Barrett’s metaplasia) and excluding other diseases (cancer, stricture)


2. Esophagram
• provides valuable information about the external anatomy of the stomach and esophagus
• provides information about the size and type of hiatal hernia that is present
• may show a ‘short’ esophagus


3. Manometry
• if dysphagia or chest pain is present, then manometry is required to exclude an esophageal motility disorder
• fully assesses the adequacy of esophageal contractions
• findings may alter the surgical approach – patients who have weak peristalsis may need a partial fundoplication instead of a complete wrap


4. pH Monitoring
• gold standard for diagnosing and quantifying acid reflux
• allows symptoms to be correlated with reflux events
• patients need to discontinue PPIs one week before the test


3. Operative Indications
• ideal candidate for an antireflux operation is a patient who responds well to medical therapy but is unwilling or unable to continue the medicines (side effects, cost)
• severe esophagitis on endoscopy
• benign strictures
• Barrett’s metaplasia without untreated high-grade dysplasia
• since GERD requires lifelong medical therapy, surgery in younger patients is the more cost effective option
• absolute contraindications are esophageal cancer or Barrett’s esophagus with untreated high-grade dysplasia
• obesity is a relative contraindication, and these patients may benefit more from an obesity operation than a fundoplication


4. Principles of Surgical Treatment of GERD
• procedure chosen should restore the functional and mechanical competence of the LES, reconstruct the hiatus, and repair any hiatal hernia if present
• must preserve the ability to swallow normally, and belch and vomit as necessary
• the following principles should be adhered to:
• restore the pressure in the LES to twice resting gastric pressure
• restore an adequate length of the LES to the positive-pressure environment of the abdomen (2.5 cm)
• allow the reconstructed cardia to relax on swallowing by avoiding injury to the vagus nerve and only using the fundus for the wrap
• the fundoplication should not increase the resistance of the relaxed sphincter to a level that exceeds the peristaltic power of the esophagus
• 360° wrap should be no longer than 2 cm and constructed over a 56 - 60 Fr bougie
• the fundoplication must be placed in the abdomen without undue tension and maintained there by approximating the crura of the diaphragm above the repair


5. Procedure Selection
• laparoscopic transabdominal approach is the preferred approach for most patients
• open transabdominal approach is reserved for patients who require a revisional reflux procedure, or who have had multiple previous abdominal procedures, or any contraindication to laparoscopy
• transthoracic approach is used when a long esophageal myotomy is required for a primary motility disorder
• complete 360° wrap (Nissen)is preferred for most patients
• partial wraps (Toupet, Dor) are used when there is poor esophageal contractility
• a short esophagus will require extensive mediastinal mobilization and/or an esophageal lengthening procedure (Collis Gastroplasty)



6. Nissen Fundoplication
• important technical points include:
• retraction of the left lateral lobe of the liver
• identify and expose both crus
• divide the short gastrics
• identify and preserve both vagus nerves
• circumferential mobilization of the esophagus
• crural closure, but too tight can lead to dysphagia
• fundus is passed posterior to stomach, and a short wrap is created over a 56 – 60 Fr bougie



• some series report 90% of patients are symptom-free at 10 years


1. Complications
1. Esophageal or Gastric Perforation
• endoscopy at the end of the procedure may help to identify this problem
• post-op, patients with unexplained fever or tachycardia should have an UGI to exclude a perforation or herniated wrap



2. Dysphagia
• very common postop problem that usually resolves within several weeks
• persistent symptoms should be evaluated with an UGI
• if the wrap is too tight, serial endoscopic dilations usually resolves the problem
• occasionally, revision of the fundoplication to a partial fundoplication will be necessary


3. Gas Bloat Syndrome
• abdominal pain, inability to belch
• caused by air trapping in the stomach
• creation of a short, floppy wrap will usually avoid this problem
• KUB shows a gas-filled stomach
• NG tube decompression immediately alleviates the symptoms
• dietary modifications and prokinetic agents are occasionally helpful, but some patients will require conversion of their full wrap to a partial wrap
• a pyloroplasty may also benefit some patients with poor gastric emptying


4. Slipped or Misplaced Wraps
• if improperly secured to the esophagus, the wrap can slip down onto the body of the stomach, leading to recurrent reflux symptoms or obstruction
• the wrap may also migrate into the thorax, leading to recurrence of reflux symptoms



7. Partial Fundoplications
1. Toupet Procedure
• 270° posterior wrap
• used for patients with documented esophageal motor abnormalities



2. Dor Procedure
• 180° anterior wrap
• similar indications and results as the Toupet procedure



8. LINX Prosthesis
• approved by the FDA in 2012
• surgically placed magnetic ring that augments the LES closure pressure but permits food passage with swallowing
• contraindications include a large hiatal hernia or severe esophagitis
• short term follow-up suggests results similar to laparoscopic fundoplication, but 10 – 20 year follow up data is not available yet
• some devices have been explanted secondary to dysphagia or esophageal erosion
• older devices are not MRI-compatible; new devices are MRI-conditional



9. Endoscopic Approaches
1. Stretta Procedure
• radiofrequency energy is applied to the muscle of the LES and gastric cardia, strengthening and thickening the muscle
• must have an LES pressure ≥ 8 mm Hg and a hiatal hernia < 3 cm long to be eligible for the procedure



2. Transoral Incisionless Fundoplication (Esophyx)
• full-thickness serosa-to-serosa plication that is 3 – 5 cm in length and 200 – 300 degrees in circumference
• questions remain about the long-term durability of the procedure