Chapter 44 – Hiatal Hernia and Gastroesophageal Reflux Disease

1067 CHAPTER 44 The role of operative treatment for gastroesophageal reflux and hiatal hernias changed dramatically during the 1990s. Once a relatively uncommon procedure, many antireflux operations and hiatal hernia repairs (mostly for paraesophageal hernias) are now performed in many centers around the world. The driving force behind increased surgical referral for treatment was the develop- ment of minimally invasive surgery. Although the techniques of antireflux operations have not changed, the approach to the operation has become more acceptable to the patient and refer- ring physician because of the small incisions, relatively short hospital stay, and lack of associated perioperative pain when compared with open approaches. Thus, the surgeon must be familiar with all aspects of evaluating and treating both entities because he or she is ultimately responsible for the successful outcome of the patient. GASTROESOPHAGEAL REFLUX DISEASE Pathophysiology The lower esophageal sphincter (LES) has the primary role of preventing reflux of the gastric contents into the esophagus. The sphincter is not a distinct anatomic structure but is a unique physiologic entity, located just cephalad to the gastroesophageal junction (GEJ). It is clearly identifiable as a zone of high pressure during manometric evaluation as the sensing device passes from the stomach into the esophagus. Several factors contribute to the generation of this high- pressure zone. The first is the intrinsic musculature of the distal esophagus. These muscle fibers differ from those in other areas of the esophagus in that they are in a state of tonic contraction. They normally relax with initiation of a swallow and then return to a state of tonic contraction. The second contributing factor to LES pressure is the sling fibers of the cardia. These fibers are at the same anatomic depth as the circular muscle fibers of the esophagus but are oriented in a different direction. They run diagonally from the cardia-fundus junction to the lesser curve (Fig. 44-1). These fibers are responsible for a significant percent- age of the lower esophageal high-pressure zone. The third con- tributing factor to the maintenance of the high-pressure zone in the distal esophagus is the diaphragm. As the esophagus passes from the chest to the abdomen, it is surrounded by the crura of the diaphragm. During inspiration, the anteroposterior diameter of the crural opening is decreased, compressing the esophagus and increasing the measured pressure at the LES. This concept is particularly important for the interpretation of esophageal manometry tracings. By convention, assess the LES pressure at mid or end expiration, thereby providing reliable, reproducible pressure measurements. The last component of the pressure gen- erated at the lower esophageal high-pressure zone is the transmit- ted pressure of the abdominal cavity. The abdominal compartment has a relatively higher pressure than the thoracic cavity. A GEJ that is firmly anchored in the abdominal cavity will be exposed to a greater transmural pressure than one that is in the posterior mediastinum. Gastroesophageal reflux may occur when the pressure of the high-pressure zone in the distal esophagus is too low to prevent gastric contents from entering the esophagus or when a sphincter with normal pressure undergoes spontaneous relax- ation, not associated with a peristaltic wave in the body of the esophagus.1 Other changes in the high-pressure zone, such as shortening, which occurs as part of cephalad displacement or as gastric distention from food or air, may also eliminate the barrier and result in reflux. Because even small changes in the high- pressure zone compromise its effectiveness, reflux episodes occur in normal people. The distinction between gastroesophageal reflux disease (GERD) and gastroesophageal reflux is a fine and important one and requires knowledge of associated symptoms, mucosal damage of the esophagus, total amount of acid expo- sure, and other factors. GERD is often associated with a hiatal hernia. Although any type of hiatal hernia may give rise to an incompetent cardia, the most common is the type I hernia (Fig. 44-2A), also called a sliding hiatal hernia. A type I hernia is present when the GEJ is not maintained in the abdominal cavity by the phrenoesopha- geal ligament (membrane). Thus, the cardia migrates back and forth between the posterior mediastinum and peritoneal cavity. The phrenoesophageal ligament is a continuation of the endo- abdominal fascia, which reflects onto the esophagus at the hiatus. It lies just superficial to the peritoneal reflection at the hiatus and continues into the mediastinum (Fig. 44-3). Although the presence of a small sliding hernia does not necessarily imply an incompetent cardia, the larger its size, the greater the risk for abnormal gastroesophageal reflux. Hiatal hernias are classified by their anatomy into three types (I to III). Types II and III hiatal hernias are often referred gastroesophageal reflux disease paraesophageal hernias summary HIATAL HERNIA AND GASTROESOPHAGEAL REFLUX DISEASE Rebecca P. Petersen, Carlos A. Pellegrini, and Brant K. Oelschlager 1068  SECTION IX  ESOPHAGUS FIGURE 44-1  Schematic drawing of the muscle layers of the esopha- gogastric  region. The  intrinsic muscle of  the esophagus, diaphragm,  and sling fibers  contribute  to  the LES pressure.  The circular muscle  fibers of the esophagus are at the same depth as the sling fibers of  the cardia.  Phrenoesophageal ligament Peritoneum (reflected) Diaphragm Outer longitudinal muscle Anterior vagal trunk Inner circular muscle Sling fibers FIGURE 44-2  The three types of hiatal hernia. A, Type I is also called  a sliding hernia. B, Type II is known as a rolling hernia. C, Type III is  referred to as a mixed hernia. GE, Gastroesophageal.  GE junctionA GE junctionB GE junctionC FIGURE 44-3  Section of the GEJ demonstrates the relationship of the peritoneum to the phrenoesophageal membrane. The phrenoesophageal  membrane continues as a separate structure into the posterior mediastinum. The parietal peritoneum continues as the visceral peritoneum as  it reflects onto the stomach.  Phrenoesophageal ligament upper and lower limbs Thoracic aorta Diaphragm Liver GE junction Subhiatal fat ring Peritoneum HIATAL HErnIA And GASTrOESOPHAGEAL rEfLUx dISEASE  ChapTEr 44  1069 SECTIO N IX ESO PH AG U S with only respiratory symptoms. This is discussed in detail at the end of this section.2 Physical Examination The physical examination of patients with GERD rarely contrib- utes to confirmation of the diagnosis. In patients with advanced disease, several observations may help identify the source of the patient’s discomfort. A patient who constantly drinks water during the interview is facilitating esophageal clearance, which may be indicative of continual reflux or distal obstruction. Other patients with advanced disease will sit leaning forward and carry out the interview with their lungs inflated to almost vital capac- ity. This is an attempt to keep the diaphragm flattened, the anteroposterior diameter of the hiatus narrowed, and thus the LES pressure elevated. Patients who have severe proximal reflux with regurgitation of gastric contents into their mouth may have erosion of their dentition (revealing yellow teeth caused by the loss of dentin), injected oropharyngeal mucosa, or signs of chronic sinusitis. The physical examination may be helpful in determining the presence of other pathologic entities. The presence of abnor- mal supraclavicular lymph nodes in a patient with heartburn and dysphagia may suggest esophageal or gastric cancer. If the patient’s retrosternal pain is reproducible with palpation, a somatic cause is likely. Short of these extreme presentations, the physical examination is generally not helpful in confirming or excluding gastroesophageal reflux as a pathologic entity. Preoperative Evaluation The preoperative workup in a patient being considered for oper- ative treatment will help confirm the diagnosis, exclude other pathologic entities, and direct the operative intervention. Endoscopy Endoscopy is an essential step in the evaluation of patients with GERD who are being considered for operative intervention. The value of the study is its ability to exclude other diseases, espe- cially a tumor, and to document the presence of peptic esopha- geal injury. The degree of injury can be measured using a scoring to as paraesophageal hernias and, although they may be associated with GERD, are also larger, more difficult hernias to treat and may be associated with acute or chronic obstructive symptoms. A type II hernia (see Fig. 44-2B), also called a rolling or para- esophageal hernia, occurs when the GEJ is anchored in the abdomen but the hiatal defect, which is usually large, provides space for viscera to migrate into the mediastinum. The relatively negative pressure in the thorax facilitates visceral migration. Usually, the fundus of the stomach migrates into the mediasti- num; however, the colon and spleen are also occasionally identi- fied. This is discussed in more detail later in this chapter (“Paraesophageal Hernias”). A type III hernia (see Fig. 44-2C) is a combination of the first two, in which the GEJ and fundus (or other viscera) are free to move into the mediastinum. A hiatal hernia is neither necessary nor sufficient to make the diagnosis of GERD, and the presence of such a hernia does not constitute an indication for operative correction. The theo- retical implications of a type I or III hiatal hernia being present is that the cardia and distal esophagus have the potential to be exposed to the negative pressure of the thoracic cavity. This would lower the pressure at the LES, thereby allowing reflux to occur more readily. Many patients with hiatal hernias do not have symptoms and do not require treatment. Clinical Presentation The most common presentation of patients with GERD includes a long-standing history of heartburn and a shorter history of regurgitation. Heartburn, when typical, is a reliable symptom. Heartburn is confined to the epigastric and retrosternal areas. It is identified as a caustic or stinging sensation. It does not radiate to the back and is not characteristically described as a pressure sensation. It is best to ask the patient to describe in detail the sensation that he or she is experiencing. Sometimes, the symp- toms will be more characteristic of peptic ulcer disease, choleli- thiasis, or coronary artery disease. The presence of regurgitation indicates progression of the disease. Some patients will be unable to bend over without experiencing the unpleasant event. A distinction between regur- gitation of undigested and digested food needs to be made. Undigested food in the regurgitant is indicative of a different pathologic process, such as an esophageal diverticulum or achalasia. In addition to heartburn and regurgitation, some patients suffer from dysphagia. Usually, dysphagia represents a mechani- cal obstruction and is more pronounced with solid food inges- tion than with liquids. If dysphagia for liquids and solids occurs at the same time and is present with the same intensity, a neu- romuscular disorder is suspected. When a patient is found to have dysphagia, peptic stricture of the distal esophagus is most likely to be the cause. However, tumor, diverticula, and motor disorders need to be excluded because this determination will affect the operative approach. Other symptoms may be present in patients with gastro- esophageal reflux. Most arise from the gastrointestinal tract; however, many patients will have symptoms involving the respi- ratory tract as well, called extraesophageal symptoms. The fre- quency of symptoms in more than 1000 patients evaluated at the gastrointestinal function laboratory of the University of Washington is shown in Table 44-1. Although many patients with gastrointestinal symptoms will also complain of extrae- sophageal symptoms, it is less common for a patient to present Table  44-1  prevalence  of  Symptoms  in  Gastroesophageal  reflux Disease* SYMpTOM prEDOMINaNCE (%) Heartburn 80 regurgitation 54 Abdominal pain 29 Cough 27 dysphagia for solids 23 Hoarseness 21 Belching 15 Bloating 15 Aspiration 14 Wheezing 7 Globus 4 *In more than 1000 patients evaluated. Symptoms reported occurred more fre- quently than once a week. 1070  SECTION IX  ESOPHAGUS system such as the Savary-Miller interpretation (1 indicates ery- thema; 2, linear ulceration; 3, confluent ulceration; 4, stricture). The extreme of mucosal injury is Barrett’s esophagus. Biopsy samples are taken to confirm the metaplastic transformation and to exclude dysplasia. The endoscope has been used to grade the so-called flap valve.3 This is interpreted on a retroflexed view of the GEJ. The flap valve is graded from 1 to 4, with 4 being a completely patu- lous junction, with the lumen of the esophagus in full view from the body of the stomach. Manometry A significant amount of information about the function of the esophageal body and LES may be obtained from stationary esophageal manometry. This test will allow the surgeon to rule out primary motility disorders such as achalasia, which may mimic the symptoms of reflux and, in patients with GERD, will allow the surgeon to plan the operative procedure better by providing data about the ability of the esophagus to clear itself of ingested food. The manometry catheter is a flexible tube with pressure-sensing devices (water, perfused, or solid state) arranged at 5-cm intervals (Fig. 44-4). The upper esophageal sphincter (UES) is notoriously difficult to analyze because it migrates during the cervical phase of swallowing. Fortunately, the char- acteristics of the UES are infrequently relevant to clinical prac- tice. The pertinent information to be gained from the manometry tracings concerns the function of the LES and the esophageal body. The LES is analyzed for mean resting pressure. This may be determined in two ways, a station pull-through and a rapid pull-through. Most laboratories report the values recorded from the station pull-through. With this method, pressures are mea- sured while the catheter is stagnant, with the radial ports at the high-pressure zone of the LES. Rapid pull-through measure- ments are obtained while the catheter is being pulled across the high-pressure zone at a rate of 1 cm/second. The latter measure- ments are usually higher than the station pull-through measure- ments because of the artifact of catheter movement. Normal pressures for a station pull-through at the LES range from 12 to 30 mm Hg. The sphincter generally relaxes to the pressure of the gastric baseline for several seconds when a swallow is initi- ated. Other information to be gained from the LES is the total length, intra-abdominal length, and location of the sphincter relative to the nares. The longer the high-pressure zone and the longer the intra-abdominal component, the greater is the barrier to reflux of gastric contents. The esophageal body is assessed to determine the effective- ness of peristalsis. With the four channels located at 3, 8, 13, and 18 cm above the LES, the patient is given a series (at least 10) of 5-mL aliquots of water to swallow. Peristaltic activity is reported as the percentage of initiated swallows that are trans- mitted to each channel successfully. Normally, a patient has more than 80% peristalsis. The second characteristic of clinical importance is the amplitude of the peristaltic wave. The ampli- tude is simply the average of the pressures generated in the distal esophagus during effectively transmitted peristaltic waves. Inef- fective esophageal motility is defined as less than 70% peristalsis or distal esophageal amplitudes lower than 30 mm Hg and is often associated with significant GERD. High-resolution manometry is now being used to charac- terize esophageal function more accurately as compared with FIGURE 44-4  representative tracings from the body of the esopha- gus and the LES show the relative positions of the pressure-sensing  channels during the study. Peristalsis  is seen after a wet swallow in  the body, whereas the LES is seen to relax to gastric baseline levels  during the same interval.  Wet swallow Body measurement LES measurement 16 96 41 4811 11 115 3318 cm 13 cm 8 cm 3 cm 99 75 17 15 27 52 15 59 19 14 24 43 55 19 15 26 77 12 59 25 15 27 54 18 63 14 102 2714 LES resting pressure Relaxation Rebound pressure 131 standard manometry. The specific advantage of high-resolution manometry is that it allows for effective continuous recording of motor activity along the entire length of the esophagus and yields a more complete and detailed picture of esophageal motil- ity. A color-contour plot with time as the x-axis and esophageal length as the y-axis is produced by the recording device. Pressure is represented by a color scale (Fig. 44-5). This method also provides a more detailed analysis of the LES and is less likely to show a decrease in LES pressure with deglutition, sometimes referred to as pseudorelaxation. pH Monitoring The gold standard for diagnosing and quantifying acid reflux is the 24-hour pH test. This study is performed by placing a thin catheter containing one or more solid-state electrodes in the esophagus. The electrodes are spaced 5 to 10 cm apart and are capable of sensing fluctuations in the pH between 2 and 7. The electrodes are connected to a data recorder that the patient wears for the period of observation. There is a digital clock displayed on the recorder. When the patient has an event (e.g., heartburn, chest pain, eructation), he or she records the event in a diary, noting the time on the recorder (Fig. 44-6). A large amount of information may be gleaned from the study—total number of reflux episodes (pH < 4), longest episode HIATAL HErnIA And GASTrOESOPHAGEAL rEfLUx dISEASE  ChapTEr 44  1071 SECTIO N IX ESO PH AG U S FIGURE 44-5  High-resolution manometry—example of a  normal  swallow.  normal  peristalsis  is  seen  after  a  wet  swallow in the body, whereas the LES relaxes during the  same interval.  29 27 24 21 18 15 12 9 6 3 0 –3 –6 9:20.1 15 sec 10:20.7 500 0 150 144 119 94 69 44 19 –10 0 mmHg UES Swallow LES Body Normal relaxation Normal peristalsis Ohms % of reflux, number of episodes lasting longer than 5 minutes, extent of reflux in the upright position, and extent of reflux in the supine position. An overall score is obtained with the use of a formula that assigns a weight to each item according to its capacity to cause esophageal injury. This value, known as the DeMeester score, needs to be less than 14.7. A simpler way to determine whether abnormal reflux is occurring is to estimate the total percentage of time that the pH is below 4 in the proxi- mal and distal channels. This is calculated by dividing how long the pH was lower than 4 by the total duration of the study and multiplying by 100. In the proximal esophagus (15 cm above the LES), acid exposure normally occurs less than 1% of the time; in the distal esophagus (5 cm above the LES), it normally occurs less than 4% of the time. The patient’s symptom diary needs to be correlated with episodes of reflux. The correlation of heartburn or chest pain with a decrease in the pH has significant clinical value because it helps confirm a cause and effect relationship. When interpret- ing these studies, it should be remembered that patients often do not maintain their normal activities and eating patterns when they have the catheter in place. Thus, their symptoms may not be as p