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AMPULLA OF VATER Anatomic, Embryologic, and Surgical Aspects

Claude Avisse, MD, Jean-Bernard Flament, MD, and Jean-Franqois Delattre, MD

The ampulla of Vater (i.e., the hepatopancreatic ampulla) corresponds ana- tomically with the dilated junction of the common bile duct and the main pancreatic duct of Wirsung before their opening into the duodenum. This ampul- lary appearance is inconstant, and its existence is disputed by some investiga- tors.

Considered more widely and realistically from the surgical viewpoint, the ampulla of Vater constitutes the junction of the biliary, pancreatic, and digestive tracts (Fig. 1). It corresponds to an anatomic and functional region that comprises (1) the junction of the common bile duct and pancreatic duct; (2) surrounded by the sphincteric system of Oddi; (3) traversing a dehiscence of the duodenal wall (fenestra choledochae); and (4) terminating at the greater duodenal papilla (or great caruncle), covered by the duodenal mucosa. The ampulla of Vater is the site of tumors, often with a threatening prognosis and the surgical treatment of which may be consequently difficult. It is also commonly the site of disorders specific to or caused by the neighboring organs that affect biliopancreatic empty- ing. The understanding of these disorders has benefited from peroperative manometric studies and from endoscopy. Numerous anatomic, embryologic, pathophysiologic, and pathologic studies of the ampulla of Vater have been performed. This article reviews only important and practical points of these stud- ies.

CHOLEDOCHOPANCREATIC JUNCTION

The junction of the main pancreatic duct and the common bile duct and their opening at the greater duodenal papilla (Fig. 2) occurs in three ways6: (1)

From the Department of Anatomy, University of Reims; and Department of Digestive Surgery, HBpital Robert DebrC, Reims, France

SURGICAL CLINICS OF NORTH AMERICA

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Figure 1. Junction of the biliaty, pancreatic, and digestive tracts (peroperative cholangio- gram).

a common duct, 1 mm to 8 mm in length, in 60% of cases; (2) a ”double- barreled” opening at the apex of the papilla in 38% of cases; and (3) separate duodenal openings for the two canals in 2% of cases. In 1720, Vater6 noted this junctional arrangement of the bile and pancreatic ducts; after having ligated the papillary orifice and injecting water into the common bile duct, he noted a reflux of fluid into the duct of Wirsung, which became expanded at the duodenal wall as a tubercle, which he called the diverticulum of the bile. The studies of Soemmer- ing6 in 1801 and of Bernard6 in 1856 established this concept of a common duct dilated into an ampulla, the so-called ampulla of Vater. Of 50 anatomic specimens studied, Papalmitiades and Rettori7 found such a common duct in only 31 cases (62%), and observed a dilatation of this common duct, justifying the term ampulla in only 2 cases (4%), so the existence of this structure is disputed, and many investigators consider it as merely an artifact of anatomic dissection.

The site of duodenal implantation of this ductal junction and the association of the main pancreatic duct of Wirsung with the common bile duct are important to consider. In 75% of cases, the greater duodenal papilla, with the two ducts, is implanted in the descending portion of the duodenum (see Fig. 2) at the junction of its posterior and medial aspects, high up but usually at its midportion. The terminal pancreatic duct is always inferior and anterior to the common bile duct (Fig. 3A). In 25% of cases, the implantation of the greater duodenal papilla is low, especially at the horizontal portion of the duodenum (Fig. 3B), to the right of the superior mesenteric vascular axis; the pancreatic duct is verticalized parallel to the left border of the common bile duct (Fig. 4).

For surgeons, the high position of the papilla can be appreciated on intraop-

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Figure 2. Choledochopancreatic junction (intraoperative cholangiogram). A, Common duct. 6, Double-barreled opening. C, Separate duodenal opening.

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TOP

B

LEFT

Figure 3. Implantation of the ductal junction and relation of the main pancreatic duct (P) to the common bile duct (C) through the papilla in the descending portion (A) and in the horizontal portion of the duodenum (B). Incision for sphincterotomy (arrow).

erative cholangiography. With the duodenum closed, the precise location of the position of the papilla calls for the insertion of a probe into the common bile duct, palpated through the duodenal wall. Duodenopancreatic stripping (i.e., the Kocher maneuver) makes the biliary-digestive confluence, normally situated deeply in the subhepatic region, superficial and easily palpable.

Figure 4. Greater duodenal papilla in the horizontal portion of the duodenum. The pancre- atic duct is verticalized, parallel to the left border of the common bile duct.

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SPHINCTERIC SYSTEM OF ODD1

The existence of a sphincter at the termination of the common bile duct was demonstrated by Oddi in 1887 as a smooth muscle sphincter, causing the passage of the bile to be intermittent. The anatomic and embryologic research of Schwegler and Boyden12 and Rettori9 indicated the independent origin of the sphincter in association with the duodenal musculature. Schwegler and BoydenI2 showed that this muscular system differentiates separately from the duodenal muscle in the mesenchyme that surrounds the ducts and that it becomes inte- grated with the duodenal wall only secondarily.

According to Papalmitiades and Ret t~r i ,~ the three elements constituting this sphincteric system are (Fig. 5A):

A common sphincter-6 mm in length, composed of thick, circular, semi- circular, and longitudinal fibers and interspersed with numerous glands that are the origin of potentially malignant vaterian tumors A specific common bile duct sphincter-10 mm in length, one third of which is outside of the duodenal wall, intraluminal A specific sphincter of the pancreatic duct-6 mm in length, of which only one fourth is extramural

According to Barraya et a1,2 these sphincters can be divided into three zones (Fig. 5B): (1) a superior occlusive sphincter; (2) a middle sphincter defining an infundibulum, which can be easily dilated; and (3) an inferior sphincter, which participates in the formation of the papilla. This sphincteric complex is situated in a dehiscence of the duodenal wall, the duodenal window.

From these concepts can be derived the existence of an extramural, intraduo- denal, or intraluminal zone of the sphincter, which alone should be involved in a possible sphincterotomy.

Figure 5. A, The sphincteric system of Oddi, according to Papalmitiades and Rettori. Duodenal wall (1). Specific sphincter of common bile duct (2). Specific sphincter of pancre- atic duct (3). Common sphincter (4). 6, The sphincteric system of Oddi, according to Barraya. Superior occlusive sphincter (1 and 2). Middle sphincter (3 and 4). Inferior sphincter (5). lnfundibulum (6).

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DUODENAL WINDOW

Classic descriptions of the duodenal window show the presence of an interruption of the duodenal muscle fibers at the point of penetration of the common bile duct and the main pancreatic duct into the duodenal wall. The muscular orifice that Schwegler and BoydenI2 called the duodenal window (fenestra choledochae) was described in detail by Papalmitiades and Ret t~r i .~ The duodenal window is a quadrilateral orifice, typically with sides of 5 mm to 7 mm. Its anterior and posterior borders correspond with the spindle-shaped separation of the superficially situated longitudinal muscle fibers of the duodenal wall. Its superior and inferior borders correspond with a separation of the deeply situated circular fibers. The window is situated on the posterior slope of the medial border of the duodenum, and its margins are united with the sphincteric block by a system of muscle fibers, the nomenclature and description of which vary among investigators. The duodenal wall surrounding the sphincteric apparatus must be respected" 6, during sphincterotomies and localized excisions of the papilla; a procedure that is too extensive risks opening the digestive lumen into the pericholedochal and retropancreatic cellular spaces and may cause severe vascular damage, so, except for carcinologic imperatives, the excision of tumors of the ampulla of Vater often requires a sacrifice: cephalic duodenopancreatec- tomy.

The association of the ductal termination with the duodenal wall (see Figs. 2 and 4) is important surgically and functionally.10 The common bile duct approaches the duodenal wall, forming an acute angle of approximately 25" to 309 open upward when the papilla is located in the descending duodenum. The terminal intraparietal part of the duct has a zigzag course between the duodenal muscle fibers, which prevents reflux of the duodenal contents toward the biliary tract regardless of the variations of intraduodenal pressure.

The main pancreatic duct, closer to horizontal, forms an angle of 60" with the duodenal wall in the frontal plane. It receives the common bile duct at its upper border and right side. In practice, the pancreatic duct is always situated below and in front of the common bile duct.

Muscle fibers (Fig. 6) coming from the margins of the duodenal window tether the termination of the biliary and pancreatic ducts to the duodenal wall. The authors borrow the description and nomenclature of these fibers from Papalmitiades and Rett~ri.~, Superficially, the C1 fibers originating from the longitudinal muscle layer at the anterior and posterior borders of the papilla join the common bile duct and pancreatic duct. The C2 fibers, given off by the circular muscle layer, arise from the lower border of the duodenal window and disappear over the pancreatic duct. The C4 fibers, also arising from the circular muscle layer, arise from the upper border of the window and disappear at the common bile duct.

Deeply, the C5 fibers, originating from the circular muscle layer at the upper border of the window, dissipate obliquely at the papilla. The C3 fibers, given off by the circular muscle layer at the inferior border of the window, have a special arrangement: The fibers coming from in front disappear over the anterior and inferior aspects of the papilla, whereas posteriorly they turn downward and are lost at the lower pole of the papilla. The lesser density of the tethering fibers behind the papilla gives rise to a weak point where mucosal hernias may develop: the mucosal diverticula of the duodenal window (Fig. 7). In the authors' experience? l1 these acquired diverticula are common in elderly patients; they may lead to dysfunction of the sphincter of Oddi and may have a major role in the development of biliary calculi, cholangitis, or pancreatitis. Lastly, the

AMPULLA OF VATER 207

c, -

Ch

FL

. w

FC

Ch \ \

FL - -

, W '

/

FC '

c,

Figure 6. A-D, The tethering fibers (Cl-C5) of the greater duodenal papilla (P) and the weak point for development of mucosal diverticula. Ch =common bile duct; W = main pancreatic duct; FC = circular fibers; FL = longitudinal fibers.

intermingling of the musculature of the duodenum and the sphincter of Oddi makes the physiology of biliopancreatic emptying complex; inflammation of the sphincter and biliary dyskinesia are well known but still ill defined clinical enti- ties.

DUODENAL MUCOSA AND THE PAPILLA

The duodenal mucosa and the greater duodenal papilla (see Fig. 3; Fig. 8), with the orifices of the common bile duct and the main pancreatic duct, can be examined by endoscopy or surgically after duodenotomy. The papilla presents as a polypoid prominence 5 mm to 10 mm in length and 5 mm in width, hidden by transverse, circular, duodenal folds. The smoothing out of these folds allows for the identification of the papilla, which is surmounted by a transverse fold,

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Figure 7. A and 6, Juxtaposed duodenal diverticulum. C and D, Interposed duodenal diverticulum.

or "hood." Above is a depression related to the invagination of the duodenal mucosa in the choledochal window. Below, one or more typically well-developed longitudinal folds-the "restraints" of the papilla-hold the papilla downward and form an essential landmark because they are the only vertical structures in the duodenal mucosa. The apex of the papilla is usually occupied by a single orifice by which the biliopancreatic secretions empty into the duodenum. This orifice is evidence of the existence of a common channel situated in the prolonga- tion of the main pancreatic duct, whereas the common bile duct joins it by a curve with an infero-left concavity. When two orifices are present, the biliary opening is always dorsal and cranial in relation to the main pancreatic duct. The main pancreatic duct is thus usually easily identifiable and can be catheterized during a surgical sphincterotomy.

For surgeons, access to the papilla for sphincterotomy or local tumoral excision requires a duodenopancreatic stripping (i.e., the Kocher maneuver), the identification as already described; a duodenotomy of the outer aspect of the

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Figure 8. The greater duodenal papilla. Papilla (1). Transverse fold (2). Longitudinal fold (3). Orifice of mucosal diverticulum (4).

organ, preferably horizontal for vascular reasons; and smoothing out of the transverse folds. The only anatomic anomaly or variation of any importance is the presence of a lesser duodenal papilla (i.e., a small caruncle), which is always situated several centimeters above the greater papilla and drains only pancreatic secretions. The patent accessory pancreatic duct of Santorini sometimes drains the entire dorsal pancreas in cases of a pancreas divisum, in which the dorsal and ventral pancreatic channels have failed to fuse.’, lo

VASCULARIZATION

The arterial vascularization of the choledochopancreaticoduodenal junction, and more globally of the entire duodenopancreatic block, has been described precisely in numerous publications, from which the authors extract the main points3, lo Three arterial supplies participate in this vascularization (Fig. 9):

Posterior and superior pancreaticoduodenal arch (Fig. 10A)-Gives off several rows of branches to the common bile duct, which form a vessel parallel to the posterior border of the papilla Ventral commissural arch (or vertical intrapancreatic arch of Evrard)- Gives off branches distributed to the duodenal wall in front of the terminal bile duct; one branch, traversing the duodenal wall near the upper border of the window, is arranged along the anterior border of the ,papilla; these two anterior and posterior axes are joined at the tip of the papilla by a finely anastomosed submucosal plexus (hence the hemorrhagic nature of juxtapapillary tumors) Anterior and inferior pancreaticoduodenal arch (Fig. 10B)-Gives off

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5

J Figure 9. Arterial vascularization of the papilla. Posterior and superior pancreaticoduodenal arch (1). Ventral cornmissural arch (2). Anterior and inferior pancreaticoduodenal arch (3). Gastroduodenal artery (4). Superior mesenteric artery (5).

some branches ramifying at the lower border of the duodenal window and participating in the juxtapapillary submucosal network

The small caliber of these vessels results in little concern with regard to the risk for hemorrhage on sphincterotomy. The same is not true if the margins of the duodenal window are transgressed because vessels of greater caliber appear here, explaining the risk for hemorrhage in local excisions. Lastly, the vessels of the duodenal wall have a horizontal direction and are distributed in anterior and posterior territories, the frontier zone of which is situated on the outer aspect. At this site, a duodenotomy should be performed, preferably horizon- tally.

The lymphatic drainage of the papilla is common to that of the right pancreas, and three sectors may be recognized5, 6,

Anterior and superior cephalic territory-The lymphatic pathways travel in the right retropancreatic process to reach the right interceliomesenteric lymph nodes Inferior cephalic territory-Drains to the right interceliomesenteric nodes bilaterally suprarenal and infrarenal, still in the right retropancreatic process Posterior and superior cephalic territory-Drains toward the retrochole- dochal lymph nodes and then relays to the interaorticocaval nodes; numer- ous variations exist, with the possibility of long collectors draining the lymph of the duodenum or pancreas directly to the juxta-aortic nodes or

AMPULLA OF VATER 211

Figure 10. Posterior and superior (A) and anterior and inferior (B) pancreaticoduodenal arches.

even the left lumbar trunk or thoracic duct; the rapid invasion of remote nodal regions justifies the consideration of cephalic duodenopancreatec- tomy as the procedure of choice for malignant tumors of the vaterian re- gion

SUMMARY

The region of the ampulla of Vater constitutes a complex anatomic and functional entity, the biliopancreaticoduodenal confluence, of which the essen- tials of this rapid review are the:

Variation in site of implantation of the greater duodenal papilla, whereas the relations between the common bile duct and the main pancreatic duct are relatively constant Presence at this site of a weak point in the duodenal wall, commonly the site of mucosal diverticula

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Interdependence of the parietal duodenal mucosa and the sphincteric

Existence of an extramural zone of this sphincter, which should be the

Danger of wide excisions of the papilla, which, apart from the risk for

The ampulla of Vater corresponds to the dilated junction of the common bile duct and main pancreatic duct, if present. The ampulla is an extensive anatomic and functional region that includes not only the choledochopancreatic junction but also the sphincter of Oddi, the whole traversing the duodenal wall to open at the greater duodenal papilla. The chief anatomic features of this biliopancreaticoduodenal junction have been reviewed, forming the basis of techniques of surgical or endoscopic sphincterotomies and localized excisions of vaterian tumors.

system of Oddi

only one involved in sphincterotomy

hemorrhage, cause a breach of the digestive barrier

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12. Schwegler RA, Boyden E A The development of the pars intestinalis of the common bile duct in the human foetus, with special reference to the origin of the ampulla of Vater and the sphincter of Oddi. Anat Rec 67441, 1937

pathology. A tentative classification. Anatomica Clinica 5275, 1984

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Department of Digestive Surgery HBpital Robert Debre

Rue du General Koenig 51092 Reims Cedex

France