Rare biliary anatotny in two patients presenting with biliary obstruction diagnosed with ERCP

GR MAY, DS REID, NB HERSHFIELD. Rare biliary anatomy in two patients presenting with biliary obstruction diagnosed with ERCP. Can J Gastroenterol 1991;5(5):161-164. Anatomic anomalies of the exrrahepatic biliary tree a re common and often incidenta l findings at endoscopic retrograde cholangiopancreatography; however, they rarely complicate therapeutic procedures such as stone extraction. The cases of two patients with biliary obstruction due to stones are presented, who were found to have the cystic d uct a rising almost J1rcctly from the ampulla. This rare anatomic variant posed problems both in terms of interpretation of the cholangiogram and removal of stones. Therapeutic enJoscopists should be aware of chis and other anomalies of the biliary tract and lif the potential problems faced in both interpretation of the cholangiogram and m therapeutic procedures.

A NOM ALI ES OF Tl IE EXTJ\AHEPATIC bilia ry tree arc relati vely common (l ).le is of great importance chat they he recognized by the surgeon at the t ime of cholccystectomy co avoid damage to t he bil iary tree; however, t hey are usually inc iue nta l findings at enuoscopic retrograde cholangiopancreatography (ERC P) a nd rarely compl icare the rapeutic e ndoscopic proceuu res.The insert io n of the cystic duct into th e commo n hepat ic duct is variabl e, with ano ma lous insertion seen in greate r than 25%.ln approximately I 0% of cases t he cystic ducr spirals around the common hepatic duct to insert on the left side (2).lnsertio n can occur at any leve l <1 long th e commo n hepatic Juct , a lthough insertion at t he ampulla is sa id to be rare and has been infrequently reported in the literature (3 ).The authors report the cases of two patie nts presenting with bi I iary o bstruc tion who were fo und to have th is rare ana tomic va ri ant a t ERCP.

CASE ONE
A n 83-year-olJ ma le with a history of chronic a tri al fi brillation presented to e mergen cy fo llowing a collapse at ho me .O n initial evaluation rhc patient was fo und to be febrile (38.3"C) with scleral icte rus.Laboratory data were unremarkable apart from an aspartate amino tra nsferase o ( 162 U/L (normal 0 to 41 ), an alkal ine phosphaLase of 4 ' 3 l U/L (no rmal 30 to 115) and a hilirubin of 59 µmnl/L (normal 3 to 20).No cardiac o r neurological ca use could he found for the collapse.Blood cu ltures we re negative.An abdominal ultrasound showed di laLion o f both the intra-a nd extrahepatic bil e ducts, with echogenic ma terial present within the dista l common bile duct .
ERCP was perfo rmed us ing an O lympus J F-1 T20 duodenoscope usin g fentanyl and diazepam for sedation.O n the initia l cholangiogram it was unclear if the common bile duct was completely obstructed or if it was an anomalous cystic duct (Figure 1 ).After repositio ning of the cannula, the common hepatic and intrahepatic ducts fill ed , showing th e cystic duct arising almost directly from the ampu lla (Figure 2).The pancreatic duct was normal.Multiple stones were present within both ducts.Following sphincterocomy, a balloon catheter was inserted separatel y into the cystic and w mmon hepatic ducts and the stones extrac ted from the respective ducts.The pat ient had rapid resolution of his jaundice and biochemica l abnormalities and is doing well after fo ur months of fo llow-up.

CASE TWO
A 76-year-old Caucasian female with a history of cho lecystecromy 15 yea rs earlier presented with a two mo nth histo ry of episod ic right upper quadrant abdom inal pain associated with nausea and vomi ting.Physical exa minatio n wa~ unremarkable.Laboratory data were within normal limits except fo r an aspartate a mino transferase of 69 U/L, an alkaline phosphatase of 165 U/L and a bilirubin of 16 µm o l/L.An ultrasound showed a dilated extrahepatic biliary tree.
ERCP was performed using an O lympus JF-!T20 duodenoscope fo llowing sedatio n with fe ntan yl and diazepam.A stone was fo und in the ampullary segment.This was extracted fo llowing sphinctemtom y.A second stone was present at the junctio n of the cystic and commo n hepa tic ducts.This duct.The gallbladder does not fill and there is a stone /rresenl wi1h111 the distal cystic duct junction was very low, just above the ampull a, giving a very short com mo n bile duct segmenr.Attempts at extraction of the second stone with a balloon catheter were unsuccessful.The catheter would preferentiall y enter t he cystic duct Jue to the angle a t which the commo n hepatic and cystic ducts joined.As the stone was not obstructing ic was left in place :md the patient was discharged.She recumed t hree weeks later, m which t ime a repeat ERCP showed that the stone had passed, and the authors were able to obtain lateral film s which defined the anatomy, showi ng a low spiral junction of the common hepatic and cystic ducts, givi ng a very short common hilc d uct ( Figure 3).

DISCUSSION
Anomalies of the extrnhepatic biliary tree have long been recognized to he both freque n t and variable ( 4 ).The frequency of these anomalies tends Lo vary depending on the method used to detect them (d issection versus radiogrn ph y ), material studied (cadaveric versus operati ve specimen s), and between series.T he significance of these anoma lies is predomirnmtly surgic,il in t hat it is important that rh cy he recognized flt the Lime of c holccysrectomy tn avoid in,idvertent injury to the bi liary Figure 2) Retrograde clwlangiogram from /)(lt1ent 1 followiiw />anial fi/lmgof the commo11 hepatic duct.The common hcp1111c and cystic duccs ame separately from t.he am/ml/a.Stones are />re~ent wnhin che discnl nstic duce and mid common he/>cwc duct.The />micreatic d11ct wm nonna/ ( entire duct not shoum) Figure 3 ) Uetmgrade cholangiogram from />atient 2 showinJ! a low s/iiwl Jzmction of the cysiic and common hepmic JucL1 within 3 cm of the am/nil/a No re.mlual mme was tiisuakcd tree anJ posloperative complications (5).For the endoscopisr, these anomalies are oft en fou nd at Lhe t ime or ERCP, and except fo r anomalies thal involve the anatomy of th e papilla (making identifica tion and cannula-t1on difficult), they rare ly complicate ERCP or therapeutic proceJures .
The junction of the c ystic duct with the common hepati c duct shows greal l'ariability, with the 'normal' angular entry of the cyslic duel into the common hepatic duct seen in only 53 tn 65% of cases (2,4,6).In apprnximarely 25% it will run a parallel course for a 1•ariable length to enter the common hepatic duct fro m the right.In l0% it takes a spiral course to enter the common hepatic duct on the left side (3 ).
In the latter situation , the site o f entry can be anywhere along the common hepatic duct , from the bifurcatio n to the duodenal papil la.O ther se ri es report the frequency of a spiral cystic Juct insertion as high as 35% with a lnw parallel insertion seen in 7% (6) .Termination of the c ystic duc t at the rapilla is said to be ra re (3).The frequency of having the cystic duc t enter the common hepalic duc t al th e ampulla, designa ted "les c hol cJ oques courts" nr 'sho rr bile duc t ' by Sale mbier (7) , is diffi cult to determine from the existing lite rature since this anatomy is usually nm diff ercn ti;ited from a low spira l or para! le i insertion with a variable length of common bi le duct rresenr.Jo hnston ( l ) define~ a low parallel in •crtion of the cystic duct a~ a rarallcl segme nt greaterthan 4 c m in le ngth .ln his series this occurred in only 2.9%.
In a series repo rted by Helo ury ct al (8), the biliary anawmy was reviewed in 250 intraoperati ve c holang iograms.
In 80% the cystic duct terminated on the right side of the commo n he patrc duct.ln only 2% was the terminatio n o f the cystic duel said to he nea r lhe papill,1, allhough this was not clearly defined.
The pathogenesis of Lhis anoma ly is n ot clear.Norm<1lly the cysl ic duct and gallbladder develop from the small caudal division of the hepatic diver-CAN J GASm OENTEROL VOL 5 Nl1 5 SEPTEMBER/(.)(TOBER 199 1 liculum during the fourt h co ~ixth weeks of emhryogenesis.It attaches to the ventral aspect of the duodenum :mJ rotates ;:ilong with d,e \'Cntra l panc reatic bud LO the dorsa l a~pect of lhe duodenum hy rhe e ighth week (9).Presumably, annma li es of cystic duct ;:inatomy could result from va riations either in the development nf lhe caudnl part of the herm1c divert1cu lum or during ro Lminn from the ventral to dorsa l aspect o f' the duodenum.
The re nre on I y a few case re purrs of d,i~ a natomy diagnosed by ERCP.
Watanabe et a l ( I 0) reported lhe case of a ratie nt wiLh a c ho ledochoduodenal fistu la and a lo ng cy~t ic duct draining into th e papilla.Thi~ paLienl rresented with a bdo minal pa in which resolved spo ntaneously and has not reyuired any further investignt ion or thcrary ( 10).Pre~umahly there wa.~ a stone impacted in the amrulla which eroded into the duodenum le is impo rtan t to he aware of such anomalies of cystic duct ana tomy to avoid m isi nterpretat io n o f the initial c holangi ograms.Therapeu tic procedures such as stone extraction and the placement of scents may a lso be complicated since it m ay be difficult to acccs:; the proximal bil iary tree depending on rhe angle o f junction between th e cystic and common hepatic duc ts.
Anomalies of t he bi le ducts: A case report of direct drain of the cystic duct inro the papilla of Yater.Acea Med Okayama 1983;37:409-15.l I. Iwamoto T, Fuj ii T, Ikeda A, Tanaka M, Nakagama F, Iwata A. Anomalies of the biliary tract.A case with d irect drain of the cyst ic ducr proved preopera t ively by endoscopic retrograde pancreaticocholangiogrnphy.Jpn J Gasrroenterol l 990;77: 1507.(Abst) 12. Kise Y, Uetsuji S, Takada 11 , Yamamurn M, Yamamoto M. Dilarntio n of the cystic duct wirh its congen ital low entry into the common hepatic duct.Am J Ga~rroenterol

162Figure l )
Figure l) Initial retrograde c/1ola11giogram from patie111 I, showing J>redominant filling of 1he cys11c duct.The gallbladder does not fill and there is a stone /rresenl wi1h111 the distal cystic duct . A preliminary re po rl of n second case of a long cystic duel draining direc tly into the papilla di,1gno~ed w1rl1 ERCP wa~ reported by Iwamoto et al (l l ).This patient had other anomalies of the biliary tree including a diverticulum of the gallbladder ( l J ).A third case was