World J. Surg. 16, 320-325, 1992
World Journal of Surgery O 1992by the Socirt~ Internationale de Chirurgie
Mechanisms of Action of Antireflux Surgery: Theory and Fact Alex G. Little, M.D. Department of Surgery, University of Nevada School of Medicine, Las Vegas, Nevada, U.S.A. Despite the absence of definitive explanations regarding either the physiologic or surgical factors which curtail gastro-esophageal reflux, effective antireflux operations exist. This article explores the theoretical factors relevant to the surgical control of reflux. These theoretical features include: (1) the pressure, length, and location of the manometrically defined lower esophageal sphincter (LES); (2) the gastro-esophageal valve as defined by the angle of His and a mucosal flap valve; and (3) the mechanical effects of a fundoplication which serve to increase the opening pressure of the cardia and optimize the physical relationships described by the law of La Place. Finally, the relation of these theoretical factors to actual operations is discussed.
Neither the mechanisms for physiologic control nor the mechanisms for surgical control of gastro-esophageal reflux have been unequivocally defined. However, many theories have been examined and defended by multiple investigators. Focusing exclusively on the question of the mechanisms of action of antireflux surgery, the most commonly accepted theories will be examined in the first part of this article. The final section will relate these theories' to the principles and techniques of actual operations. History
Until the middle of this century, with Allison's hallmark paper in 1951 being the first clear signal of the change in focus [1], surgical attention was on the anatomic defect of hiatal hernia rather than the real problem, the physiologic defect of incompetence of the cardia. Not until this proper orientation was in place could both medical and surgical attention be aimed at the true pathology. This is not to deny the close relationship between hernias and gastro-esophageal reflux which, even if poorly understood, seems to exist [2--4]. The important point is that operations which anatomically repair a hiatal hernia without incorporating the technical features designed to restore cardial competence do not succeed in curtailing reflux [1, 5]. Early surgical leadership was supplied half a century ago by Belsey and Nissen, both of whom worked from a combination of clinical insight and extensive experience to develop empiriReprint requests: Alex G. Little, M.D., Professor and Chairman, Department of Surgery, University of Nevada School of Medicine, 2040 W. Charleston #601, Las Vegas, Nevada 89102, U.S.A.
cally the initial successful operations for incompetence of the cardia, i.e., gastro-esophageal reflux disease. Nissen used the gastric fundus to wrap and thereby bolster an abdominal esophagogastric anastomosis following a transthoracic repair of an esophageal perforation [6]. When, in contrast to other of his patients with an esophagogastrostomy, the patient failed to develop signs or symptoms of gastro-esophageal reflux, Nissen alertly recognized the effect of the fundoplication and began to apply the principles of this operation to patients with reflux [7]. In contrast to thisexperience, where lessons learned from one problem were applied to another, Belsey approached the problem of reflux primarily. He began with premises derived from clinical experience that a successful antireflux operation must restore an acute angle of entry of the esophagus into the stomach, must ensure an intra-abdominal portion of esophagus, and must bring about "the restoration of conjugal relations between the cardia and right crus" [8]. He then developed and refined his operation by modifying the technique so that the operation evolved from the original Mark I to the final Mark IV, as the desired results of balancing curtailment of reflux with maintenance of the ability to belch and vomit were sought. A lesson from this experience, relevant for all surgeons, is that Belsey refused to publish his technique, thereby jeopardizing his opportunity to establish eponymic primacy, until he had both settled on the final version and long-term clinical follow-up results were available. Theoretical M e c h a n i s m s of Antireflux Surgery
The most likely surgical factors, which may work either singly or in combination, are restoratio'n of the lower esophageal sphincter (LES), creation of a gastro-esophageal valve, and the mechanical effects of a fundoplication. These concepts are based upon considerations such as the role of an intra-abdominal esophageal segment, the function of the gastric smooth muscle used to wrap or surround the lower esophagus, the physiologic ramifications of the law of LaPlace, and the ability of surgery to restore the normal length-tension relationship of the muscle responsible for production of the LES. The success of each specific antireflux operation is not dependent upon the same surgical factors. The differences, which help to explain the variability in results and complications, are discussed in the section reviewing specific operations.
A.G. Little: Mechanisms of Action of Antireflux Surgery
Lower Esophageal Sphincter Restoring or improving the muscular tone of the LES is a feature of all antireflux procedures. Pre-operative manometry in reflux patients usually reveals a relatively low, i.e.,
World Journal of Surgery O 1992by the Socirt~ Internationale de Chirurgie
Mechanisms of Action of Antireflux Surgery: Theory and Fact Alex G. Little, M.D. Department of Surgery, University of Nevada School of Medicine, Las Vegas, Nevada, U.S.A. Despite the absence of definitive explanations regarding either the physiologic or surgical factors which curtail gastro-esophageal reflux, effective antireflux operations exist. This article explores the theoretical factors relevant to the surgical control of reflux. These theoretical features include: (1) the pressure, length, and location of the manometrically defined lower esophageal sphincter (LES); (2) the gastro-esophageal valve as defined by the angle of His and a mucosal flap valve; and (3) the mechanical effects of a fundoplication which serve to increase the opening pressure of the cardia and optimize the physical relationships described by the law of La Place. Finally, the relation of these theoretical factors to actual operations is discussed.
Neither the mechanisms for physiologic control nor the mechanisms for surgical control of gastro-esophageal reflux have been unequivocally defined. However, many theories have been examined and defended by multiple investigators. Focusing exclusively on the question of the mechanisms of action of antireflux surgery, the most commonly accepted theories will be examined in the first part of this article. The final section will relate these theories' to the principles and techniques of actual operations. History
Until the middle of this century, with Allison's hallmark paper in 1951 being the first clear signal of the change in focus [1], surgical attention was on the anatomic defect of hiatal hernia rather than the real problem, the physiologic defect of incompetence of the cardia. Not until this proper orientation was in place could both medical and surgical attention be aimed at the true pathology. This is not to deny the close relationship between hernias and gastro-esophageal reflux which, even if poorly understood, seems to exist [2--4]. The important point is that operations which anatomically repair a hiatal hernia without incorporating the technical features designed to restore cardial competence do not succeed in curtailing reflux [1, 5]. Early surgical leadership was supplied half a century ago by Belsey and Nissen, both of whom worked from a combination of clinical insight and extensive experience to develop empiriReprint requests: Alex G. Little, M.D., Professor and Chairman, Department of Surgery, University of Nevada School of Medicine, 2040 W. Charleston #601, Las Vegas, Nevada 89102, U.S.A.
cally the initial successful operations for incompetence of the cardia, i.e., gastro-esophageal reflux disease. Nissen used the gastric fundus to wrap and thereby bolster an abdominal esophagogastric anastomosis following a transthoracic repair of an esophageal perforation [6]. When, in contrast to other of his patients with an esophagogastrostomy, the patient failed to develop signs or symptoms of gastro-esophageal reflux, Nissen alertly recognized the effect of the fundoplication and began to apply the principles of this operation to patients with reflux [7]. In contrast to thisexperience, where lessons learned from one problem were applied to another, Belsey approached the problem of reflux primarily. He began with premises derived from clinical experience that a successful antireflux operation must restore an acute angle of entry of the esophagus into the stomach, must ensure an intra-abdominal portion of esophagus, and must bring about "the restoration of conjugal relations between the cardia and right crus" [8]. He then developed and refined his operation by modifying the technique so that the operation evolved from the original Mark I to the final Mark IV, as the desired results of balancing curtailment of reflux with maintenance of the ability to belch and vomit were sought. A lesson from this experience, relevant for all surgeons, is that Belsey refused to publish his technique, thereby jeopardizing his opportunity to establish eponymic primacy, until he had both settled on the final version and long-term clinical follow-up results were available. Theoretical M e c h a n i s m s of Antireflux Surgery
The most likely surgical factors, which may work either singly or in combination, are restoratio'n of the lower esophageal sphincter (LES), creation of a gastro-esophageal valve, and the mechanical effects of a fundoplication. These concepts are based upon considerations such as the role of an intra-abdominal esophageal segment, the function of the gastric smooth muscle used to wrap or surround the lower esophagus, the physiologic ramifications of the law of LaPlace, and the ability of surgery to restore the normal length-tension relationship of the muscle responsible for production of the LES. The success of each specific antireflux operation is not dependent upon the same surgical factors. The differences, which help to explain the variability in results and complications, are discussed in the section reviewing specific operations.
A.G. Little: Mechanisms of Action of Antireflux Surgery
Lower Esophageal Sphincter Restoring or improving the muscular tone of the LES is a feature of all antireflux procedures. Pre-operative manometry in reflux patients usually reveals a relatively low, i.e.,
