A Clinical and Anatomical Study of Anomalous Terminationsof the Common Bile Duct Into the Duodenum

HAROLD H. LINDNER, M.D.,* VAN A. PENA, PH.D., ROBERT A. RUGGERI, M.S.

Termination of the common bile duct into the duodenum wasstudied in 1000 patients by operative cholangiograms obtainedfrom 5 different San Francisco Bay Area hospitals. The resultsindicate the strong probability that the duodenal biliarypapilia is anomalously placed in at least 13% of the 1000patients studied. Comments relative to the importance of thisfact to surgeons and radiologists are made, and suggestion of apossible causative factor for the anomalies is proposed.

A LTHOUGH it is commonly appreciated that there isan inordinately large number of anomalies asso-

ciated with the excretory ducts of the liver, com-paratively little attention has been paid to the positionof entrance of the common bile duct into the duodenum.Our interest in this subject was stimulated by a paperof Keddie, Taylor and Sykes."1 These authors investi-gated the site of termination of the common bile duct in120 patients, and surprisingly reported anomalies in 23%of these individuals. A thorough search of the literaturehas revealed that several other authors have also beeninterested in anomalies of common bile duct termina-tion, namely Lurje,'2 Dowdy,2 and Schulenberg.14 SeeTable 1 for a synopsis of their data. Single casereports of rare anomalous terminations of the commonbile duct have been reported by other authors.1 3'13'15

In our estimation, none of the series reported in Table1 was of sufficient size or reported in sufficient detailto warrant more than cursory interest. True, Schulen-berg14 reported 1093 cases, but only mentioned anomaliesof the site of entrance of the common bile duct into theduodenum in a short paragraph. We felt that the high

* Clinical Professor of Surgery and Topographical Anatomy; Uni-versity of California, San Francisco.

Reprint requests: Harold H. Lindner, Department of Anatomy,School of Medicine, University of California, San Francisco,California.

From the Departments of Surgery andTopographical Anatomy, University ofCalifornia, San Francisco, California

incidence of anomalies in Keddie's 120 patients war-ranted further study, both numerically, and in more de-tail. As a consequence, we decided to study 1000operative cholangiograms and to report completely ourresults relative to common bile duct terminationanomalies.

Descriptions of anomalies of the termination of thecommon bile duct are nonexistent in the standard ana-tomical texts. Of interest is the fact that a minuteperusal of the sections on common bile duct anatomyin the British and American Gray's Anatomy,4'5 Hollins-head's exhaustive Anatomy for Surgeons,8 and Hol-linshead's Textbook of Anatomy9 fail to mentionanomalies of the terminal course and site of termina-tion of the common bile duct.The most outstanding feature of the so-called normal

anatomy of the extrahepatic biliary system is its highdegree of variability. Our brief discussion of thenormal anatomy of the distal biliary tree will focus onthe pancreatic and intraduodenal portions of the com-mon bile duct and most particularly on the site oftermination of the common duct.The pancreatic portion of the common duct extends

from the cephalic border of the pancreatic head to thesite of entrance of the duct into the duodenal wall, adistance which varies from a short 2.5 cm to one aslong as 6 cm. The length of the duct will of necessitydepend on its site of entrance into the duodenum. Thepancreatic portion of the common duct may be retro-pancreatic, lying between the dorsal surface of the

626

Vol. 184 . No. 5 ANOMALOUS TERMINATI(

TABLE 1. Summary of Selective Literature

Numberof % Type of

Author, Institution Patients Anomalies Study

Lurje, 194 8.25 CadaverMoscow, U.S.S.R., dissection1937

Dowdy et al. 100 92 (Normal) AutopsyHermann Hospital, dissectionHouston, Texas1962

Schulenberg, 1093 5.6 OperativePretoria, South cholangio-Africa grams1970

Keddie et al. 120 23 OperativeRoyal Infirmary, cholangio-Manchester, Eng. grams1974

pancreas and the retroperitoneal tissues of the pos-

terior abdominal wall. However, the duct may liewithin the substance of the dorsal portion of thepancreatic head, close to the medial border of thedescending duodenum. The retroduodenal and superior

pancreatic portions of the duct normally curve gentlyto the left. The inferior arc of this curvature isformed by the distal portion of the pancreatic course

of the common bile duct as it turns relatively sharplyto the right to terminate in the mid-portion of thedescending duodenum. Occasionally, the common ductwill abruptly turn laterally toward the descending por-

tion of the duodenum and enter it at a right angle.The common bile duct passes through the duodenum

in an oblique manner, similar in some respects to thepassage of the ureters through the bladder wall. Theclassical anatomical description of the site of termina-tion of the common duct places the entrance of the ductinto the posteromedial wall of the descending duodenumat a site superior to the crossing of the duodenum bythe transverse colon. This site is about 7 cm distalfrom the pylorus.The major pancreatic duct also empties into the duo-

denum through the duodenal papilla. Prior to the timethe common bile duct and the major pancreatic ductpenetrate the duodenal wall, the two ducts becomeclosely related and run parallel to one another for a

distance of from 2 mm tQ 10 mm. During this closeextra-duodenal association, junction of the two ductsmay occur just external to the duodenal wall. Theducts may also join during their tangential course

through the duodenal wall, or the common and majorpancreatic ducts may enter separately and individuallydischarge upon the eminence of the major duodenalpapilla.

)NS OF THE BILE DUCT 627

The intraduodenal portion of the common bile ductpasses through the bowel wall, and if joined by themajor pancreatic duct just proximal to the duodenalpapilla, forms the ampulla of Vater. In about 70%o ofcases there is an ampulla of Vater formed in suchfashion by the confluence of the major pancreatic ductand the common bile duct.10 The ampulla reaches fromthe point of confluence to the exit of the joined ductson the duodenal papilla. It averages only 2 mm to 3 mmin length. In those cases in which there is no con-fluence of the two ducts, there is no ampulla of Vater.The ampulla terminates at the ostium of the majorduodenal papilla on the posteromedial surface of theduodenal lumen.The ampulla as well as the entire intraduodenal

portion of the common duct and the intraduodenalsegment of the major pancreatic duct are surroundedby a sheath of circular smooth muscle fibers. Thisencircling musculature is known as the sphincter ofOddi.

r. hepatic duct

cystic ductX)

FIG. 1. Termination of the common bile duct into the duodenumas determlined by operative cholangiography. Duodenal divisions:duodenal bulb; descending duodenum: normal, that part extending fromthe duodenal bulb to approximately 3 cm distal to the midpoint;low, below the center portion, but above the angle between thedescending and transverse duodenum; angle, the junction betweenthe descending and transverse duodenum; transverse duodenum;ascending duodenum.

LINDNER, PENA AND RUGGERI

FIGS. 2a and b. Normal operative cholangiograms. The common bileduct terminates into the posteromedial wall of the descendingduodenum.

The portion of the sphincter of Oddi which sur-

rounds the common bile duct is the thickest and mostextensive of the duodenal smooth muscle prolonga-tions. It stretches from the point of entrance of thecommon duct into the duodenal wall all the way to theampulla, if present, and is called the sphincter chole-dochus. It increases in thickness as it runs proximallyin the direction of the duodenal lumen. The muscle of

the sphincter choledochus also extends distally to even-tually completely encircle the ampulla and thus formthe sphincter ampullae. Some circular mnuscle fibersextend a short distance proximally from the ampulla tosurround the lower end of the pancreatic duct. Thesefibers form the pancreatic sphincter. It becomes obvioustherefore, that the sphincter of Oddi is made up of thecondensation of three separate sphincteric groupings,those about the common bile duct alone, those about theterminal part of the pancreatic duct and those fiberssurrounding the discharging of the duodenal eminence.Longitudinal smooth muscle fibers are present betweenthe surfaces of the common bile duct and the pancreaticduct. They facilitate the flow of bile through the commonduct, shortening the duct as they contract. However,these longitudinal smooth muscle fibers are not part ofthe sphincteric muscle complex.

This short anatomical description of the terminalportion of the common bile duct relates only to thosecases in which the common bile duct empties into thecentral portion of the descending duodenum. As far aswe know there is no information available at presentrelative to the mode of entrance of the common bileduct into the duodenal lumen in those cases where itsentrance is into the lower descending or the trans-verse portion of the structure. In those few cases inwhich visualization of the common bile duct resultedin a concomitant visualization of the major pancreaticduct (common channel), it appears that the mode andmethod of junction is similar to that described for theentrance of the two ducts into the midportion of thedescending duodenum. However, the number of cases sonoted is far too small for us to do more than speculateon the ductal and sphincteric arrangements when ananomalous site of common duct entrance is present.Our contribution in this paper is to emphasize thefact that a high percentage of sites of duct entranceis anomalous and as such is of major clinical significance.

Methods

The operative cholangiograms of 1000 unselectedpatients who have had biliary tract surgery have beencarefully examined. The cholangiograms were obtainedfrom five San Francisco Bay Area hospitals: The Uni-versity of California, San Francisco General Hospital,a division of the University of California, St. Mary'sHospital, San Francisco, Letterman Army Hospital,San Francisco and Oak Knoll Naval Hospital, Oakland.

In order to be selected for this study, cholangiogramshad to be reasonably clear and easily interpreted.Cholangiograms which did not clearly demonstrate thesite of entrance of the common bile' duet into theduodenum were routinely excluded from the study.This meant that only 40Wo of the cholangiograms ex-

628 Ann. Surg. * November 1976

ANOMALOUS TERMINATIONS OF THE BILE DUCT

FIG. 3. A low termination of the common bile duct into the descend-ing duodenum. The common bile duct enters below the center portion,but above the angle between the descending and transverse duodena.

amined were accepted for the study. As a result, wefeel that the roentgenograms used in this study were ofsuch quality that, anatomically, the course of the com-mon bile duct and the segments of the duodenumcould be delineated clearly. For the purpose of re-cording the site or termination of the common bile duct,we divided the duodenum into five sections (Fig. 1).This approach is similar to the method reported byKeddie.11Measurements of individual duodenal and common

duct lengths were made in each case. This was done inan attempt to determine whether length, configuration,or overall shape, had any influence upon anomaloussites of entrance of the common bile duct. In anattempt to discern any relationship between the siteof entrance of the common bile duct and variationsin the form and length of the duodenum, shapes of the

629........ ...... Fll .... . .. .. .......}.}.... ^.....

.:

OS fflAW£C

FIG. 4. Angle: the common bile duct terminates at the junction be-tween the descending and transverse duodena.

duodenum were compared with the four common pat-terns reported by Hollinshead.8

Results

Of the 1000 cases which were examined, the commonbile duct entered the descending duodenum (Figs. 2a, 2b,3, 6) in 86.9% of patients. It entered the angle, the junc-tion between the descending and transverse duodena, andthe transverse duodenum in 13.1% of individuals (Figs. 4,5a, b). Thus a significant number of variations from thenorm are present. We did not observe any terminations ofthe common bile duct in the duodenal bulb, ascendingduodenum, or any extra duodenal loci (Fig. 7). The dataare organized according to hospital and site of entranceof the common bile duct, and are presented in Table 2.The average length of the descending duodenum was

TABLE 2. Resuilts: Distribution of Common Bile Duct Terminations in 1000 Operative Cholangiograms

UCSF SFGH St. Mary's Letterman Oak KnollTotal

Patients % Patients % Patients % Patients % Patients % Patients %

DescendingDuodenumNormal 175 82.2% 153 76.5% 234 85.1% 168 78.1% 91 93.9%W 821 82.1%Low 10 4.7% 17 8.5% 0 0 21 9.8% 0 0 48 4.8%

Angle 15 7.0%W 22 11.0%70 15 5.5% 15 7.0%Ho 6 6.1% 73 7.3%TransverseDuodenum 13 6.1% 8 4.0% 26 9.4% 11 5.1% 0 0 58 5.8%

Vol. 184 . NO. i

LINDNER, PENA AND RUGGERI

FIGS. 5a and b. Examples of the common bile duct terminating inthe transverse duodenum. (left) Note the distinct drop inferiorly ofthe common duct in this case.

measured as 9 cm. We found no apparent relationshipbetween the length of the duodenum and anomalies ofthe termination of the common bile duct. In patientswhose common bile ducts entered the duodenumproximal to the junction of the descending and trans-verse duodena, the average length of the common bileduct was 4.8 cm (range 2.5 cm to 6.9 cm). In thosecases where the entrance of the common bile duct wasanomalous, the average length of the common bileduct was 6.6 cm (range 3.8 cm to 10.1 cm). We alsoobserved no relationships between either the length orsite of entrance of the common bile duct and the shapeof the duodenum.

DiscussionObviously the site of entrance of the common bile

duct into the duodenum becomes of great importance tothe surgeon and to the radiologist in diseases of theextra-hepatic biliary tract both diagnostically and thera-peutically. We feel this to be true for the followingreasons: 1) It is apparent from our studies that in atleast 13% of cases the duodenal papilla will appear atthe junction of the descending and transverse duodenaor the transverse portion of the duodenum far removedfrom its normal location in the supra-colic portion ofthe descending duodenum. In at least another 5%, wehave found the duodenal eminence to be well below thelevel ofcrossing of the duodenum by the transverse colon.In order to accurately inspect, probe, flush and manipu-late the biliary ampulla and eminence through aduodenotomy incision, one would have to mobilize thetransverse colon or perhaps even the ligament of Treitz,so that such a duodenotomy could be carried out.This would entail further time consuming surgicalmanipulation and possibly add to the surgical mor-bidity. One wonders whether on those few occasionswhen the surgeon has been unable to locate the duo-denal biliary eminence, it has been occupying a posi-tion in the lower descending or transverse duodenum.2) Although the creation of false biliary passagessecondary to operative procedures upon the distal com-mon duct is a relatively rare event, perhaps one of thereasons for its occurrence is the surgeon's attempt tonegotiate a curve which is not there or failure tonegotiate a curve which is there. On all of the filmswhich show an abnormal site of biliary entrance, itappears to us that this is a distinct possibility. 3) In thosecases where a radical pancreatectomy is to be carried out,leaving behind only a narrow rim of pancreatic tissue,ostensibly containing the common bile duct, we feel itis of great importance to do an operative cholangiogrambefore such a procedure is carried out, so that theoperating surgeon may have some idea as to the site

630 Ann. Surg. o November 1976

v ."....44:4:t".

ANOMALOUS TERMINATIONS OF THE BILE DUCT 631of entry of the common duct into the duodenum.This knowledge, it would seem to us, would tend todiminish greatly the possibility of a postoperative pan-creatico-biliary fistula. 4) As we have correlated ourdata, which have presented us with an amazingly highpercentage of anomalous sites of entry of the commonduct into the duodenum, one thought has constantlybothered one of us (HHL). That thought is that whyin some almost 40 years of experience in biliary tractsurgery have I not encountered this anomaly? One verycogent suggestion6 lies in the physiologic peristalticactivity inherent in the duodenum. Some observers have N1_compared the duodenum to a churn, a site of majorperistaltic movement with a continual contraction andshifting of duodenal position carried out during the earlystages of food digestion. Can it be possible that thosecholangiograms which show a remarkable distal openingof the common duct into the duodenum may be show-ing this anomaly as a result of a forward extensionor thrust of that portion of the duodenum whichwould normally be classified as mid-descending duo-

FIG. 7. An example of a iatrogenic anomaly. The common bileduct enters at the junction of the pylorus and duodenal bulb dueto a choledochoduodenostomy.

denum? One fact against this conjecture is that cholangio-grams were taken during surgery with the patient on

'~~~~ starvation status and obviously not physiologically in-- : dclined to drive his duodenum forward. 5) We have

noticed quite definitely that those common ducts that aregoing to enter the inferior duodenal angle or proximaltransverse duodenum tend to drop directly inferiorlyfrom the inferior surface of the first portion of theduodenum rather than curving gently to the left and

F then compensating with a right curve. Moreover, dur-ing its descent inferiorly, the common bile duct, inthose cases in which it terminates anomalously, fre-quently lies closely adjacent to the right lateral borderof the vertebral column, or actually lies ventral to thevertebrae. These observations were made previously byHicken et al., and are so constant that we feel it

-........ _should signal to both the radiologist and surgeon thepossibility of an anomalous duodenal entrance. These

4#s_@!facts should also serve as a danger signal in thosecases where the common duct is blocked by a stone ortumor and its distal portion cannot be filled with dye.In such cases the surgeon should proceed with cautionso that a false passage will not be made.

AcknowledgmentsFIG. 6. Patient with three common bile ducts which rejoin andpenetrate the duodenum as a single duct, entering the duodenum at its We wish to acknowledge the kind assistance of W. K. Birken-normal entrance site. hagen, M.D., Resident, Department of Surezerv, St. Marv's Hospital,

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632 LINDNER, PEIA AND RUGGERI Ann. Surg. * November 1976San Francisco, R. S. Bothwell, M.D., Major, M.C., Department ofSurgery, Letterman Army Hospital, San Francisco, and G. Metz, M.D.,Captain, USN, Department of Surgery, Oak Knoll Naval Hospital,Oakland, who were responsible for the collection of the cases attheir individual hospitals.

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Orifice. Fortschr. Geb. Roentgenstr. Nuklearmed, 93:515,1960.

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15. Swartley, W. B. and Weeder, S. D.: Choledochus Cyst withDouble Common Bile Duct. Ann. Surg. 101:912, 1935.