Even though the increasing use of medications that inhibit gastric acid secretion, such as proton pump inhibitors, has made elective antisecretory operations essentially nonexistent, these medications remain part of the surgeon's armamentarium in dealing with patients who remain refractory to maximal medical therapy for ulcer disease, and in some selected cases for patients with ulcer perforation and bleeding. To understand the importance of the technical details in the execution of antisecretory operations, it is necessary to fully appreciate the anatomy of the vagus nerve and the gastric microvasculature, as well as the physiology of acid secretion, mucosal barrier function, and gastric motility, which are expanded upon in the following text.
Tests of Vagal Control of Acid Secretion
Historically, vagal control of acid secretion has been assessed by measuring acid secretion in response to various stimuli. Acid secretion can be measured directly by the placement of a tube into the stomach, through which gastric juice is aspirated and the titratable acidity is measured by adding known quantities of 0.1 N NaOH. Gastric output is measured at baseline and after stimulation with pentagastrin or sham feeding. Measurements of gastric acid output pre– and post–vagotomy operations can be measured to assess the efficacy of vagotomy.8,9 Acid secretion also can be assessed semiquantitatively, using pH-sensitive dyes, such as Congo red, that coat the mucosa and turn color when acid is being secreted from the gastric glands.10,11 Although the former analytic methods permit accurate and quantitative assays of secretory capacity before and after the operation, the latter colorimetric methods can provide relatively rapid means of assessing secretory capacity of the stomach during the operation itself. These tests are rarely used today with the increasing use of medications that inhibit gastric acid secretion such as proton pump inhibitors and the consequent rarity of performing elective antiulcer gastric acid–reducing operations.
Vagal Regulation of Gastric Motility and Emptying
As stated by Professor David Johnson in a previous edition of this book, “… Only when one fully understands the physiologic rationale of highly selective vagotomy will be one sufficiently motivated to do it well.” This statement was made not in reference to the innervation of parietal cells that secrete HCl, but to the neural regulation of gastric motor function and emptying. The vagus dominates the motor activity of the normally functioning stomach in three ways. First, it mediates receptive relaxation and gastric accommodation; that is, the relaxation of the gastric fundus when intraluminal pressures in the proximal esophagus and stomach are increased by the presence of chyme. Second, the vagus mediates increases in antral myoelectrical activity that result from distention of the proximal stomach by chyme. Third, the vagus appears to mediate coordination of pyloric emptying with antral myoelectrical activity, in response to changes in proximal gastric motor activity, and perhaps in response to changes in composition and pH of duodenal content.12
It should be recognized that while truncal or selective vagotomy interrupts the vagal pathways to the antrum and pylorus, all three forms of vagotomy (truncal, selective, and highly selective) abolish receptive relaxation and gastric accommodation. It has been claimed that in the absence of pyloric scarring or stenosis, vagotomy only temporarily impairs gastric emptying. This rationale has been used to justify combinations of selective and relatively nonselective approaches, such as a posterior truncal and anterior highly selective (or anterior seromyotomy) vagotomy. Such arguments become important in thinking about potential adverse consequences of laparoscopic approaches to the vagus and the need for, and choice of, drainage procedures. The assumptions that antral/pyloric coordination will return after truncal vagotomy or that gastric emptying after pyloromyotomy is as good as that after pyloroplasty now seems valid.13–15 In addition, the spectrum of complications following such mixtures of approach has now been characterized and is not substantially different than those reported in symmetric operations.15,16 Nevertheless, for open or laparoscopic procedures, it is advisable to use the same caution in utilizing mixtures of approach or dispensing with drainage procedures after truncal or selective vagotomy.
Open Approaches to the Vagus
Patient Position, Incisions, and Exposure
To perform a complete vagotomy, access to the upper part of the stomach and lower esophagus is crucial. It is helpful for the operating surgeon, standing on the patient's right, to wear a headlight. When access to the duodenum is required, as in a gastrectomy, excellent exposure is available through a chevron incision. However, in most patients, both thin and obese, a midline incision carried up along the xiphoid will be adequate. In the obese, extension of the incision below the umbilicus facilitates exposure. Placing the patient in reverse Trendelenburg position is helpful. A nasogastric (NG) tube is placed with its tip at the most dependent portion of the greater curvature. The NG tube helps to keep the position of the esophagus in mind. A self-retaining retractor is required. We use an upper abdominal self-retaining retractor that provides excellent accessories for securing wide exposure to the upper abdomen, and by means of well-placed Mikulicz's pads, for holding the small bowel and transverse colon in the lower abdomen (Fig. 26-1). Some surgeons advocate routine mobilization of the left lobe of the liver by dividing the left triangular ligament. This mobilization is not always necessary and, when the lobe is floppy, can impede exposure. If this maneuver is performed, the lateral segment of the left lobe is held upward and to the right by a Richardson or Herrington-type retractor accessory. Care must be taken to place sponges or a pack between the retractor attachment and liver, and not to put much tension on the liver. Otherwise, fracture of the liver parenchyma and bleeding will result.
The use of the Bookwalter retractor for exposure of the upper abdomen.
Truncal vagotomy (TV) is performed in conjunction with some form of drainage procedure. In the elective setting, it is used in conjunction with antrectomy for definitive management of refractory symptoms of duodenal ulcer, pyloric channel ulcer (gastric ulcer type III), or gastric ulcers combined with duodenal (Dragstedt) ulcers. In the current era of highly effective antisecretory therapies such as omeprazole, and anti-Helicobacter antibiotics, the main indication for TV and antrectomy is in the setting of pyloric outlet obstruction with a long-standing history of ulcer symptoms or complications such as bleeding and perforation. TV and pyloroplasty are reserved for emergency operations for complications such as bleeding or perforation. Occasionally, TV plus gastroenterostomy will be an appropriate compromise when the duodenum is too scarred to permit safe antrectomy and duodenal closure. The anatomy of the vagal trunks and nerves of Latarjet has been reviewed17 and is shown schematically in Figs. 26-2 and 26-3.
The distribution of the anterior vagus nerve is shown. The dotted line indicates the line of dissection. Note that it goes around the incisura to within about 6 cm of the pylorus. The gastrocolic omentum has been partially divided to permit access to the posterior nerve of Latarjet and to allow the stomach to be grasped and used as a retractor. Note that the gastroepiploic arteries are carefully preserved. (Redrawn, with permission, from Johnston D. Vagotomy. In: Schwartz SI, Ellis H, eds. Maingot's Abdominal Operations. 8th ed. Norwalk, CT: Appleton-Century-Crofts; 1985. After R.N. Lane.)
The posterior wall of the stomach and posterior nerve of the Latarjet are shown. The terminal Y fork of the nerve is preserved, and all of the branches to the stomach are divided, leaving about 5 cm of the distal portion of the stomach innervated. (Redrawn, with permission, from Johnston D. Vagotomy. In: Schwartz SI, Ellis H, eds. Maingot's Abdominal Operations. 8th ed. Norwalk, CT: Appleton-Century-Crofts; 1985. After R.N. Lane.)
Using a Mikulicz pad or carefully applied Babcock clamps, the assistant places downward traction on the greater curvature of the stomach, thereby placing traction on the gastroesophageal junction and lower esophagus. The first step is to incise the peritoneal covering of the gastroesophageal junction. The peritoneum is opened horizontally, from the angle at the lesser curvature to the cardiac notch at the greater curvature. The surgeon's thumb and right index finger are used in a blunt dissection to encircle the esophagus. When teaching this maneuver, it is not uncommon for the trainee to confuse the right crus of the diaphragm with the esophagus itself or even the posterior vagal trunk. Extra time spent at this juncture to correctly identify all structures is an essential aspect in teaching the operation. A Penrose drain can be passed around the junction in order to place more effective downward traction on the gastroesophageal junction. When encircling the esophagus, the surgeon stays wide of the esophagus in order to prevent inadvertent entry into the lumen and to include the vagal trunks. In the course of this maneuver, the posterior vagal trunk usually will be palpated as a taut cord.
A single anterior vagal trunk is usually identified in the anterior midportion of the esophagus, 2–4 cm above the gastroesophageal junction (Fig. 26-4). At this level, however, it is not uncommon for vagal fibers to be distributed between two or three smaller cords. These cords are palpable as much as they are visible and can be separated from surrounding esophageal muscle fibers using a nerve hook. These trunks are individually lifted up, and 2- to 4-cm segments of each are separated from surrounding tissues. A medium-sized clip is applied at the most superior end, and a clamp is applied inferiorly. The 2-cm length of nerve is resected and a clip is applied below the clamp; small bleeders are cauterized precisely. If it has not been done, the esophagus should be more widely mobilized for a distance of 4–5 cm above the gastroesophageal junction. Smaller, individual vagal fibers that ramify from the main trunks toward the lesser curvature and the cardiac notch then can be identified and cut or cauterized. The “criminal nerve” of Grassi, discussed in more detail in the section describing parietal cell vagotomy, also may be identified here, wrapping around the cardiac notch from its origin in the posterior trunk. The posterior vagal trunk itself usually will have been identified along the right edge of the esophagus. If the anterior vagus has already been divided, the esophagus is more mobile. This mobility allows the surgeon to place downward traction on the gastroesophageal junction, or along the most caudal portion of the greater curvature, thereby applying gentle tension on the EG junction, which causes the posterior vagus to “bowstring” and make it easier to identify. A 2- to 4-cm segment is separated from surrounding tissues, its margins marked with clips, and resected. Major branches of the anterior vagus and the posterior vagal trunk should be sent to pathology for examination in frozen section. Care should be taken to note the results of the pathologist's frozen section diagnosis in the dictated operative note.
Division at both vagus nerves. (Redrawn, with permission, from Zinner MJ. Atlas at Gastric Surgery. New York, NY: Churchill Livingstone; 1992. After Gloege.)
Selective vagotomy (SV) is not commonly practiced in the United States, but it has found favor with European surgeons, who prefer not to cut the posteriorly derived vagal branch that innervates the small intestine and pancreas and anteriorly derived vagal branch that supplies the gallbladder and liver. There is evidence that preservation of such branches can avoid alterations in gallbladder motility that might lead to stasis and stone formation.18 However, it is not clear whether preservation of the small intestinal and pancreatic nerves protects against some symptoms of the dumping syndrome.19–22, SV involves interruption of both nerves of Latarjet and therefore does not avoid the need for a drainage procedure.22 Thus the main indication for SV may be in patients undergoing elective antrectomy with vagotomy for refractory ulcer symptoms or obstruction.
Exposure to the vagus, gastroesophageal junction, and esophagus is obtained in the same way that the surgeon would perform TV. Anteriorly, the nerve of Latarjet is identified by following the anterior vagal trunk as it descends from the esophagus to the lesser curvature of the stomach. Frequently, the descending branch of the left gastric artery is in close proximity to the site where the hepatic/gallbladder branches take off toward the liver in the gastrohepatic (lesser) omentum. A segment of the nerve of Latarjet is severed between clips and sent for examination on frozen section. The most expeditious way to perform this maneuver is to cross-clamp the portion of the lesser omentum that contains the artery and nerve, ligating and dividing these structures together (Fig. 26-5). The dissection continues upward along the lesser curvature, gastroesophageal junction, and esophagus. Division and ligation of blood vessels and nerves in this bundle avoids the hepatic/gallbladder branches and denervates the cardia, as was described for TV. This dissection opens up the plane for dissection and ligation of the posterior nerve of Latarjet.
Selective vagotomy. The descending branch of the left gastric artery has been divided, and the anterior gastric branches of the anterior vagus are about to be divided.
Highly Selective Vagotomy
Generally accepted indications for highly selective vagotomy (HSV) include elective management of intractable symptoms of duodenal ulcer disease, emergency treatment for perforated duodenal ulcer, and emergency treatment of perforated gastric ulcer when the ulcer is to be excised in a wedge rather than resected in continuity with the distal stomach. HSV also has been advocated for management of bleeding gastric or duodenal ulcers, but this has not been widely practiced. Finally, there is published experience in pyloric outlet obstruction using HSV in combination with finger or endoscopic balloon dilation,19,23–25 but systematic audits of long-term persistence or recurrence rates of obstructing symptoms have yet to be reported.
A number of variations of the technique have been described and all are not reviewed here. However, it is worth cataloguing the decisions that the surgeon must make in preparing for and performing this operation. The first decision is whether to use Congo red dye for intraoperative testing of the completeness of vagotomy, in countries where it is approved for this application. It may be difficult, and sometimes contraindicated, to perform endoscopy in the setting of acute bleeding or perforation. If the test is to be used, the endoscopic equipment and reagents should be assembled in the operating room before the operation begins.26 Conceptually then, the operation is divided into four phases: (1) exposure and gastric mobilization; (2) dissection of the anterior leaf of the lesser omentum; (3) dissection of the posterior leaf of the lesser omentum; and (4) dissection of vagal fibers traveling to the stomach along the distal esophagus.
Exposure and Gastric Mobilization.
Exposure of the vagus nerves, esophagus, and gastroesophageal junction is obtained as described previously. A wide-bore (18F) NG tube should be placed by the anesthesia team. A number of authors have emphasized the importance of the stomach as a retractor in this operation. We recommend mobilization of the distal part of gastrocolic omentum. The dissection should be carried outside the gastroepiploic arcade, in order to avoid loss of any blood supply to the greater curvature. Congenital adhesions between the stomach and peritoneum overlying the pancreas are divided sharply. The goal of this dissection is to obtain sufficient mobility of the stomach so that it can be rotated upward and to the patient's right, thus permitting visualization of the posterior leaf of the lesser omentum and the posterior nerve of Latarjet through the lesser sac. The nerve can be seen running close to the descending branch of the left gastric artery. Vagal fibers can be seen running transversely toward the lesser curvature.
Dissection of the Anterior Leaf of the Lesser Omentum.
The anterior leaf of the lesser omentum now is dissected. The next decision point is to define the distal margin of the dissection of the branches of the nerve of Latarjet (Fig. 26-6). An important landmark is the incisura angularis. The “crow's foot” is the neurovascular bundle that innervates the junction of the corpus and antrum, and has three characteristic branches from which its name derives. These nerves contain motor branches to the antrum and secretory branches to the oxyntic mucosa. Thus, leaving this bundle intact makes the antisecretory operation less complete, but fully severing it may lead to disturbances in gastric emptying. Two approaches for defining the distal margin of the dissection have been advocated. First, one may arbitrarily begin the dissection at a predetermined point 6–7 cm proximal to the pylorus, a distance that usually corresponds to the most proximal of the three branches of the crow's foot. Alternatively, one may identify this most proximal branch and begin the dissection there. It is helpful to begin the dissection a few centimeters proximal to the agreed-upon distal margin, because strong traction during subsequent parts of the operation may cause traction injury on the antral motor branches and vessels that accompany them. These last few centimeters are dealt with last.
Highly selective vagotomy. A. Planned line of dissection of the anterior leaf of the gastrohepatic ligament. B. The dissection is carried out, beginning just proximal to the crow's foot and extending upward, to the left of the gastroesophageal junction. (Redrawn, with permission, from Zinner MJ. Atlas of Gastric Surgery. New York, NY: Churchill Livingstone; 1992. After Gloege.)
The assistant provides downward and leftward traction on the greater curvature, thus placing tension on the anterior nerve of Latarjet as it runs along the lesser curvature. The hepatic fibers usually are visualized without difficulty in the upper part of the lesser omentum. It is helpful to “score” the serosa of the lesser curvature, from the incisura to the cardia, and then transversely across the gastroesophageal junction. The incision is performed with dissecting scissors or a no. 15 knife, not electrocautery. This maneuver widens the gap between the nerve and the gastric wall. Individual vessels run transversely from the lesser omentum onto the lesser curvature. These structures are ligated in continuity with 3-0 silk ligatures before division. (We avoid the use of hemostats in this dissection.) This part of the operation is performed gently and should not cause blood loss. The dissection proceeds along the lesser curvature until the gastroesophageal junction is reached. The left anterior aspect of the esophagus is now uncovered, and, for the moment, the dissection stops. Care should be taken not to continue up the right side to avoid interrupting the main anterior vagus.
Dissection of the Posterior Leaf of the Lesser Omentum.
The posterior leaf of the lesser omentum then is dissected. Care should be taken in setting up exposure for this part of the operation. In one approach, the stomach is rotated upward and to the patient's right. Alternatively, the posterior leaf can be reached by working through the anterior leaf as illustrated in Fig. 26-7. Using the thumbs and fingers, the gastroesophageal junction is “rolled” counter clockwise so that the posterior wall moves to the right and the anterior wall moves to the left. The nerve branches and their accompanying vessels then are ligated in continuity and divided. The dissection should not be carried to less than 6 cm from the pylorus. To avoid the main left gastric vessels, this approach to the dissection should be carried about two-thirds of the distance along the lesser curvature. After reaching the left gastric vessels, the surgeon returns to the anterior approach, ligating and dividing the remainder of the posterior leaf through the window in the anterior leaf.
Parietal cell vagotomy. A. The line of dissection of the posterior leaf of the gastrohepatic ligament is illustrated. B. The dissection is carried out through the window created by prior dissection of the anterior leaf. (Redrawn, with permission, from Zinner MJ. Atlas of Gastric Surgery. New York, NY: Churchill Livingstone; 1992. After R.N. Lane.)
Dissection of the Distal Esophagus.
The goal of this dissection is to clear the distal esophagus of all nerve fibers for a distance of approximately 5 cm above the gastroesophageal junction. The importance of this part of the dissection is well documented.27 It should be noted that the prior dissection of the lesser omentum has allowed the main vagal trunks to move upward and to the patient's right, thereby minimizing the risk of damaging the main trunks in this part of the dissection. The operative technique requires that this dissection stay close to the lesser curvature and esophagus. Any dissection toward the tissues to the right (ie, toward the main vagal trunks) should be avoided.
This part of the procedure begins with the dissection of the left side of the esophagus (Fig. 26-8). Denuding the surface can be performed gently, using a finger or “peanut” dissector to isolate the adventitia that contains nerves, vessels, and lymphatics. This dissection is where the “criminal nerve” of Grassi is likely to be encountered. Tissues are ligated in continuity and divided. This dissection should also clear 2 or 3 cm of the cardia, just distal to the gastroesophageal junction, and small fibers running to the greater curvature will be divided here. It is usually not necessary to divide any of the short gastric arteries.
The serosa has been cut to the left of the esophagus, and fatty areolar tissue to the left of the esophagus, containing nerve fibers, blood vessels, and lymphatics, is hooked up by the right index finger. The angle of His and the adjacent esophagus with a 2- to 3-cm portion of the fundus of the stomach are thoroughly cleaned. In this way, small nerve fibers running to the proximal 3-cm portion of fundus (“criminal nerves of Grassi”) are eliminated. (Redrawn, with permission, from Johnston D. Vagotomy. In: Schwartz SI, Ellis H, eds. Maingot's Abdominal Operations. Norwalk, CT: Appleton-Century-Crofts; 1985. After R.N. Lane.)
The anterior aspect of the esophagus is now cleared of vagal fibers (Fig. 26-9). Gentle traction and lifting of the fibers will isolate them for division between ligatures or by cautery. We prefer ligation in continuity with fine (4-0 or 5-0) silk to avoid injury to the esophageal muscle. The posterior aspect is now reexposed with downward traction of the gastroesophageal junction and a counter clockwise rotation of the distal esophagus. Working through the window of the anterior leaflet, the upward branches of the left gastric artery are visualized as they pass to the cardia and the gastroesophageal junction. They are ligated in continuity and divided. The dissection continues upward along the cardia and gastroesophageal junction, until it is possible to encircle the lower esophagus with a Penrose drain. Downward traction on the gastroesophageal junction is provided by this drain, and additional nerve fibers are seen in the adventitia. Smaller fibers are cauterized while held away from the esophageal muscularis, whereas larger ones are ligated with clips or fine silk and divided. Throughout this dissection, the positions of the nerves of Latarjet and the main trunks should be checked.
Anterior gastric branches of the anterior vagal trunk running downward on the anterior surface of the esophagus are gently lifted with a hemostat and either ligated or clipped before being divided or destroyed with diathermy. (Redrawn, with permission, from Johnston D. Vagotomy. In: Schwartz SI, Ellis H, eds. Maingot's Abdominal Operations. 8th ed. Norwalk, CT: Appleton-Century-Crofts; 1985. After R.N. Lane.)
The final part of the operation involves completion of the distal dissection to the crow's foot and checks for hemostasis. A number of authors have in the past suggested that reperitonealization of the lesser curvature be performed. Although we do not routinely do this, the rationale for this maneuver is that the devascularization that is part of HSV may lead to small areas of necrosis of the gastric wall and localized perforations. Such leaks have been reported in about 0.2% of patients.28,29 Also, it has been argued that reperitonealization might impede reestablishment of vagal nerve connections to the gastric wall.30 The reperitonealization would thus protect against such leaks. The reperitonealization can be performed by inversion of the serosa of the lesser curvature with running or continuous 3-0 long-acting absorbable suture. Alternatively, a vascularized pedicle of omentum can be used to cover the deserosalized lesser curvature. Bleeding complications have been reported with this latter method, but it minimizes tension within the gastric wall.
Reoperative Approaches to the Vagus Nerves
Approximately two-thirds of patients with duodenal or pyloric channel ulcer recurrence after an initial antisecretory operation (TV, SV, or HSV) have evidence of persistent (or possibly reestablished) vagal innervation.9,31,32 Although many such recurrences are amenable to medical regimens, a small fraction ultimately may be considered for reoperation, especially if surgery is required to control an acute complication such as bleeding or perforation following a period of ulcer-related symptoms. Prior surgery will have made the standard approaches to the lesser curvature and gastroesophageal junction hazardous, which is often caused by dense adhesions to a previously mobilized left lobe of the liver. Thus, two approaches to the vagus, both nonselective, may be considered for completion of the failed vagotomy, especially if it was performed in conjunction with antrectomy. It should be stressed that when such a reoperation is contemplated, especially in a nonemergent setting, it is prudent to obtain some form of acid secretion profile to document the hypersecretory state. Also, because of the nonselective nature of the completion vagotomy, an antrectomy or drainage procedure must be performed.
In the setting in which standard access is difficult due to prior surgery, Barroso and associates have utilized a transabdominal suprahepatic approach to the vagi.33 A high midline incision is used, with mechanical retraction to elevate the subcostal margin. An 18F NG tube is placed. The triangular, left coronary, and falciform ligaments and adhesions are divided, permitting downward retraction of the left lobe. Using the NG tube, the esophagus and hiatus are located. The esophagus and vagi are dissected at the level of the diaphragm at the hiatus and incised anteriorly for a distance of 3–5 cm, exposing the esophagus at the lower mediastinum. The trunks are easily identified and ligated in the untouched lower thoracic esophagus. The hiatus is closed with interrupted nonabsorbable sutures.
A transthoracic approach to this region has also been used,34 and with the advent of thoracoscopy it may become increasingly attractive for this limited set of patients. Specific issues in anesthesia for this approach have been reviewed.35 The operation is performed through the left chest, entered via the eighth intercostal space. An NG tube is positioned with its tip in the stomach. After division of the inferior pulmonary ligament, the base of the left lung is retracted upward and laterally. The mediastinal pleura overlying the esophagus is incised for a distance of 8 cm. The esophagus is then mobilized and encircled with a Penrose drain. Vessel loops are used to retract individual vagal trunks as they are identified. The supradiaphragmatic anterior vagus nerve may have multiple branches above the level of the diaphragm, but rarely are there multiple branches at a level 4 cm above the diaphragm.30 In contrast, the posterior vagus has multiple branches above the level of the diaphragm, but is a single trunk at this level more than 90% of the time (Fig. 26-10). Thus, the best opportunity for a complete vagotomy lies 4 cm above the diaphragm for the posterior trunk. A circumferential dissection of the 6 cm of esophagus just above the diaphragm is carried out, with technique similar to that performed during the HSV. Tube thoracostomy is required for 2–3 days postoperatively.
Anatomy of the anterior (A) and posterior (B) vagus nerves above the diaphragm in 50 cadavers. Incidence of each anatomic group is indicated by percentage. (Redrawn, with permission, from Jackson RG. Anatomy of the vagus nerve in the region of the lower esophagus and stomach. Anat Rec. 1949;103:1.)