- Email: [email protected]
Changes of intrahepatic bile duct dilatation after surgery for congenital dilatation of the bile duct
Changes of Intrahepatic Bile Duct Dilatation After Surgery for Congenital Dilatation of the Bile Duct By Ryoji Ohi, Nobuo Koike, Yutaro Matsumoto, Nobuhiro Ohkohchi, and Morio Kasai Senclai, Japan 9 Of 47 patients suffering from congenital dilatation of the bile duct whose intrahepatic bile ducts could be clearly demonstrated by operative cholangiogram or preoperative ERCP, 39 patients (83%) had dilatation of the intrahepatic bile ducts. Followup studies in infants and children ranging from 1 year to 11 years after their corrective operation for congenital dilatation of the common bile duct showed no morbidity that was attributed to the presence of the dilatation of the intrahepatic bile ducts. ECHO grams in 21 patients revealed marked decrease in size of the intrahepatic bile ducts except for t w o patients with huge cystic dilatation of the intrahepatic bile ducts. These findings justify the employment of the standard operative procedure for the treatment of congenital dilatation of the bile duct even if it is associated with dilatation of the intrahepatic bile ducts. 9 1 9 8 5 by" Grune & Stratton. Inc. INDEX W O R D S : Congenital dilatation duct; choledochal cyst.
of the bile
XCISION OF the dilated common bile duct and the establishment of bile drainage by hepatico-enterostomy has been accepted as a standard surgical procedure for the treatment of congenital dilation of the bile duct] -5 The management of the dilatated intrahepatic bile ducts in patients with this disease, however, still remains to be determined. The purpose of this paper is to report the results of follow-up studies paying attention to dilatation of the intrahepatic bile ducts in patients with congenital dilatation of the bile duct.
E
MATERIALS AND METHODS From 1959 through 1982, 60 patients, 14 males and 46 females, with congenital dilatation of the bile duct have been
From the Division of Pediatric Surgery and the 2nd Department of'Surgery, Tohoku University School of Medicine, Sendai, Japan. Presented before the 16th Annual Meeting of the Pacific Association of Pediatric Surgeons, Fukuoka, Japan, May 15~19, 1983. Address reprint requests to Ryoji Ohi, MD, Division of Pediatric Surgery, Tohoku University School of Medicine, 1-1 Seiryo-eho, Sendai, 980 Japan. 9 1985 by Grune & Stratton, Inc. 0022 3468/85/2001-0007503.00/0 138
treated at the 2nd Department of Surgery, Tohoku University Hospital. Patients with biliary atresia associated with the cystic dilatation of the extrahepatic bile ducts were excluded from this study. Of 47 patients subjected to evaluation of the intrahepatic bile duct by operative cholangiogram or preoperative ERCP, 39 patients (83%) proved to have an associated dilatation of the intrahepatic bile ducts. The form of dilatation was cystic in 14 cases and fusiform in 25. A follow-up questionnaire requesting information on the growth and postoperative morbidity was mailed to all patients with congenital dilatation of the bile ducts. Routine laboratory examinations and ultrasonographic studies were carried out on patients at our outpatients clinic. The ultrasonographic study was done using 3.5 M H z probe of ALOKA ECHO Camera SSE-250. Right subcostal oblique scan was performed to demonstrate the intrahepatic bile duct along with the main branch of the portal vein. Hepatobiliary scintigraphy using 99mTc-EHIDA was performed on two children with huge cystic intrahepatic bile ducts. Isotope counts taken every one minute in the hepatic area were processed with a gamma camera and a processing unit was used to establish the time-activity curve. The disappearance rate of radionucleotide (K value) which corresponds to biliary excretory function was estimated from the time-activity curve and calculated from the formula K
LnCl5
LnC30 15
x 100 (%/min)
(LnC~5.30: Counts in natural logarithm at 15 and 30 minutes after injection of the radionucleotide).6
RESULTS
Table 1 shows the relationship between the types of the extrahepatic and intrahepatic bile duct dilatation at the time of operation. Out of 22 patients with cystic dilatation of the common bile duct, intrahepatic bile duct dilatation was cystic in 10 cases and fusiform in the remaining 12. On the other hand, all 12 cases with fusiform dilatation of the common bile duct revealed fusiform dilatation of the intrahepatic bile duct. Since all patients had undergone the standard operation, namely, excision of the dilated common bile duct and Roux-Y hepatico-jejunostomy, intrahepatic involvement of the bile ducts had not been treated at the time of operation. The questionnaire was returned by 30 out of 39 patients (77%) that had associated intrahepatic bile duct dilatation. There were 7 males and 23 females, and their age at follow-up ranged from 2 to 28 years. The follow-up period Journal of Pediatric Surgery, Vol 20, No 2 (April), 1985: pp 138-142
139
INTRAHEPATIC BILE DUCT DILATATION CHANGES Table 1. Form o f Dilatation in Positive Intrahepatic Bile Duct Dilatation
Common Bile Duct
Intrahepatic Bile Ducts
Cystic
22
(56%)
Cystic Fusiform
10/22 12/22
(45%) (55%)
Fusiform
12
(31%)
Cystic Fusiform
0 12/12
(100%)
Unknown
5
Cystic Fusiform
was less than 12 months in 3 cases, 1 to 3 years in 7, 3 to 5 years in 4, and more than 5 years in 16 cases. The answers to the questionnaire on morbidity after surgery were as follows. No particular morbidity was attributed to the remaining intrahepatic bile duct dilatation. Postoperative abdominal pain in 6 cases was never associated with fever and jaundice. Cancer arising from the intrahepatic bile duct and intrahepatic cholelithiasis was not encountered in the follow-up studies. The liver function tests examined in 19 cases did not show any significant abnormal value except for slightly high levels of alkaline phosphatase in four cases. The evaluation of postoperative changes in the form and size of intrahepatic bile ducts by ultrasonographic study in 21 patients is summarized in Table 2. No dilatation of the common hepatic duct and intrahepatic bile duct was found at follow-up in 7 of 9 patients who had cystic dilatation of the intrahepatic bile ducts at the time of radical operation. In two patients with extremely large intrahepatic cystic dilatation shown in Figure 1, however, the dilatation still remained unchanged at one year and two years after surgery, respectively. On the other hand, in all of the patients who had a fusiform dilatation of intrahepatic bile ducts at the time of operation, the dilatation was not located at the porta hepatis or inside the liver. Figure 2 presents an ultrasonogram that demonstrates persistent dilaTable 2. Results of Follow-Up Study: Postoperative Change of Intrahepatic Bile Ducts (US)
Form of Intrahepatic Bile Duct Dilatation at Operation Cystic Fusiform Total
9 12 12
Normalized 7/9 12/12 19/21 (90%)
Still Dilated 2/9 O/12 2/21 (10%)
4/5 1/5
tation of the intrahepatic bile duct two years after operation in a 9-year-old girl. The disappearance rate of radionucleotide calculated from the time-activity curve in two patients with huge intrahepatic bile duct dilatation increased from 2.2 to 3.1 and from 1.8 to 2.4, respectively (normal: 3.8 +_ 1.0). These changes indicate that biliary excretory function of these two patients improved even though the intrahepatic bile duct dilatation persisted. DISCUSSION
In 1939, McWhorter first described the association of intrahepatic bile duct dilatation with congenital dilatation of the bile duct. 7 According to additional information on this condition provided by many authors, 8'9 the incidence of intrahepatic bile duct dilatation is fairly common in patients with congenital dilatation of the bile duct. It is necessary, however, to make a clear distinction between the intrahepatic bile duct dilatation in patients with extrahepatic bile duct dilatation and that of Caroli's disease] ~ In our series of 47 patients, we evaluated the configuration of the intrahepatic bile ducts by operative cholangiograms or ERCP and found 39 cases (83%) of associated dilatation of the intrahepatic bile ducts. Our incidence of association is similar to those of other recently reported series. Approximately half of the intrahepatic bile ducts were cystic and the other half fusiform when the dilatation of the common bile duct was cystic. On the other hand, all intrahepatic bile duct dilatation was fusiform in patients with fusiform extrahepatic dilatation. It has been our policy to carry out free drainage of the bile at the porta hepatis for patients with congenital dilatation of the bile duct. We perform radical excision of the dilated extrahepatic bile duct and hepatico-jejunostomy in Roux-Y fashion as a standard surgical procedure
140
OHI ET AL
Fig 1. Operative cholangiograms of two patients demonstrating extremely large intrahepatic bile duct dilatation.
for this disease. When there is a stricture at the site of the hepatic duct, we always resect the stenotic portion and choose a more proximal dilated intrahepatic duct for the anastomosis. Since all patients have undergone the standard operation, intrahepatic dilatation of the bile ducts was not removed at the time of their operation. Considerable data is available 4'5'1~ on the postoperative follow-up of patients with congenital dilatation of the bile duct, but little work has been done to evaluate the postoperative disappearance or persistence of the intrahepatic bile duct dilatation. Several kinds of sequelae, such as frequent episodes of cholangitis, intrahepatic cholelithiasis, and cancer arising from the wall of the intrahepatic bile duct cyst could seem to be unavoidable because of the persistence of the
intrahepatic bile duct dilatation. From the results of the present study, the physical growth of patients with this disease was almost normal in spite of persistent intrahepatic bile duct dilatation. There was also no particular morbidity connected with intrahepatic bile duct dilatation. Although 23 out of 30 patients (77%) showed abnormal levels of alkaline phosphatase before operation, only 4 out of 19 patients (21%) revealed abnormal values at follow-up. Other liver function tests examined in follow-up study were within normal limits. It is concluded from these results that the intrahepatic bile duct dilatation left untreated did not exert unfavorable influences upon the postoperative course of these patients. The ultrasonographic study at follow-up revealed that the fusiform dilatation of the intra-
INTRAHEPATIC BILE DUCT DILATATION CHANGES
141
Y.T. 9y.
Preop,.
Postope.24mo.
L
P
~ V f+. Fig 2. Ultrasonograms showing the remaining dilated intrahepatic bile duct t w o years after operation in a 9-year-old girl.
hepatic bile ducts was reduced in size after free drainage at the porta hepatis. The majority of the cystic dilatation of the intrahepatic bile duct markedly decreased in size after surgery. In case of extremely large intrahepatic bile duct dilatation, the size of the duct, however, remained unchanged. Tsuchida et al ~2 reported that in 4 out of 11 tong-term survivors of this disease, intrahepatic bile duct dilatation persisted; they stressed that, also in the case of cystic dilatation, the intrahepatic bile ducts were unlikely to decrease in size after surgery. The controversy still continues as to whether intraheptatic bile duct dilatation in patients with this disease has a congenital origin or is secondary to intraluminal pressure of the intrahepatic bile ducts. On the basis of available evidence on the ultrasonographic studies at follow-up, it is reasonable to say that fusiform dilatation of the intrahepatic bile duct in case of extrahepatic dilatation is always secondary. We cannot deny, however, the possibility that a congenital developmental anomaly of the intrahepatic bile ducts
may lead to some of the cystic dilatation of the intrahepatic bile ducts. Serial evaluation of the bile excretory function estimated by hepatobiliary scintigraphy in patients with huge intrahepatic bile duct dilatation, revealed gradual improvement to almost normal levels. This indicates that persistent intrahepatic bile duct dilatation does not disturb the hepatobiliary function. As far as the surgical treatment of intrahepatic bile duct dilatation in patients with congenital dilatation of the common bile duct is concerned, hepatic lobectomy is usually limited because of the anatomical or the pathological situation of the liver. Fortunately, intractable sequelae, such as liver abscess and intrahepatic cholelithiasis resulting from the intrahepatic bile duct dilatation, were seldom encountered. Therefore, these follow-up results justify the employment of the standard operative procedure, namely excision of total extrahepatic bile duct cyst and free drainage from the porta hepatis for the treatment of this disease even if there is an
142
OHI ET AL
a s s o c i a t e d d i l a t a t i o n of t h e i n t r a h e p a t i c bile ducts. H o w e v e r , c a r e f u l a n d serial f o l l o w - u p studies a r e r e c o m m e n d e d w h e n a h u g e cystic d i l a t a t i o n of t h e i n t r a h e p a t i c bile d u c t is f o u n d at t h e t i m e of o p e r a t i o n . REFERENCES
1. Kasai M, Asakura, Y, Taira Y: Surgical treatment of choledochal cyst. Ann Surg 172:844-851, 1970 2. Ishida M, Tsuchida Y, Saito S, et al: Primary excision of choledochal cyst. Surgery 68:884-888, 1970 3. Kasai M, Suzuki H, Ohi R: Operative procedure for choledochal cyst. Jap J Surg 7:145-150, 1977 4. Flanigan DP: Biliary cysts. Ann Surg 182:635 643, 1975 5. Klotz D, Cohn BD, Kottrneier PK: Choledochal cysts: Diagnostic and therapeutic problems. J Pediatr Surg 8:271283, 1973 6. Ohkohchi N, Ohi R, Kasai M, et al: Assessment of
hepatic function after hepatic portoenterostomy for biliary atresia by the time-activity curve using 99m-Tc-EHIDA. J Jap Soc Pediatr Surg 19:631-639, 1983 (Jap) 7. McWhorter GL: Congenital cystic dilatation of the bile and pancreatic ducts. Arch Surg 38:397 411, 1939 8. Tsuchida Y, Ishida M: Dilatation of the intrahepatic bile ducts in congenital cystic dilatation of the common bile duct. Surgery 69:776-781, 1971 9. Todani T, Narusue M, Watanable Y, et al: Management of congenital choledochal cyst with intrahepatic involvement. Ann Surg 187:272-280, 1977 10. Corali J, Soupault R, Kossakowski J, et al: La dilatation polykystique cong6nitale des voies biliailes intra-h6patiques. Essai de classification. Sem H6p Paris 34:488 495, 1958 11. Kim SH: Choledochal cyst: Survey by the surgical section of The American Academy of Pediatrics. J Pediatr Surg 16:402-407, 1981 12. Tsuchida Y, Saito S, Honna T, et al: Clinical situation of intrahepatic bile duct dilatation. Shonika Mook 5:107117, 1979 (Jap)
of the bile
XCISION OF the dilated common bile duct and the establishment of bile drainage by hepatico-enterostomy has been accepted as a standard surgical procedure for the treatment of congenital dilation of the bile duct] -5 The management of the dilatated intrahepatic bile ducts in patients with this disease, however, still remains to be determined. The purpose of this paper is to report the results of follow-up studies paying attention to dilatation of the intrahepatic bile ducts in patients with congenital dilatation of the bile duct.
E
MATERIALS AND METHODS From 1959 through 1982, 60 patients, 14 males and 46 females, with congenital dilatation of the bile duct have been
From the Division of Pediatric Surgery and the 2nd Department of'Surgery, Tohoku University School of Medicine, Sendai, Japan. Presented before the 16th Annual Meeting of the Pacific Association of Pediatric Surgeons, Fukuoka, Japan, May 15~19, 1983. Address reprint requests to Ryoji Ohi, MD, Division of Pediatric Surgery, Tohoku University School of Medicine, 1-1 Seiryo-eho, Sendai, 980 Japan. 9 1985 by Grune & Stratton, Inc. 0022 3468/85/2001-0007503.00/0 138
treated at the 2nd Department of Surgery, Tohoku University Hospital. Patients with biliary atresia associated with the cystic dilatation of the extrahepatic bile ducts were excluded from this study. Of 47 patients subjected to evaluation of the intrahepatic bile duct by operative cholangiogram or preoperative ERCP, 39 patients (83%) proved to have an associated dilatation of the intrahepatic bile ducts. The form of dilatation was cystic in 14 cases and fusiform in 25. A follow-up questionnaire requesting information on the growth and postoperative morbidity was mailed to all patients with congenital dilatation of the bile ducts. Routine laboratory examinations and ultrasonographic studies were carried out on patients at our outpatients clinic. The ultrasonographic study was done using 3.5 M H z probe of ALOKA ECHO Camera SSE-250. Right subcostal oblique scan was performed to demonstrate the intrahepatic bile duct along with the main branch of the portal vein. Hepatobiliary scintigraphy using 99mTc-EHIDA was performed on two children with huge cystic intrahepatic bile ducts. Isotope counts taken every one minute in the hepatic area were processed with a gamma camera and a processing unit was used to establish the time-activity curve. The disappearance rate of radionucleotide (K value) which corresponds to biliary excretory function was estimated from the time-activity curve and calculated from the formula K
LnCl5
LnC30 15
x 100 (%/min)
(LnC~5.30: Counts in natural logarithm at 15 and 30 minutes after injection of the radionucleotide).6
RESULTS
Table 1 shows the relationship between the types of the extrahepatic and intrahepatic bile duct dilatation at the time of operation. Out of 22 patients with cystic dilatation of the common bile duct, intrahepatic bile duct dilatation was cystic in 10 cases and fusiform in the remaining 12. On the other hand, all 12 cases with fusiform dilatation of the common bile duct revealed fusiform dilatation of the intrahepatic bile duct. Since all patients had undergone the standard operation, namely, excision of the dilated common bile duct and Roux-Y hepatico-jejunostomy, intrahepatic involvement of the bile ducts had not been treated at the time of operation. The questionnaire was returned by 30 out of 39 patients (77%) that had associated intrahepatic bile duct dilatation. There were 7 males and 23 females, and their age at follow-up ranged from 2 to 28 years. The follow-up period Journal of Pediatric Surgery, Vol 20, No 2 (April), 1985: pp 138-142
139
INTRAHEPATIC BILE DUCT DILATATION CHANGES Table 1. Form o f Dilatation in Positive Intrahepatic Bile Duct Dilatation
Common Bile Duct
Intrahepatic Bile Ducts
Cystic
22
(56%)
Cystic Fusiform
10/22 12/22
(45%) (55%)
Fusiform
12
(31%)
Cystic Fusiform
0 12/12
(100%)
Unknown
5
Cystic Fusiform
was less than 12 months in 3 cases, 1 to 3 years in 7, 3 to 5 years in 4, and more than 5 years in 16 cases. The answers to the questionnaire on morbidity after surgery were as follows. No particular morbidity was attributed to the remaining intrahepatic bile duct dilatation. Postoperative abdominal pain in 6 cases was never associated with fever and jaundice. Cancer arising from the intrahepatic bile duct and intrahepatic cholelithiasis was not encountered in the follow-up studies. The liver function tests examined in 19 cases did not show any significant abnormal value except for slightly high levels of alkaline phosphatase in four cases. The evaluation of postoperative changes in the form and size of intrahepatic bile ducts by ultrasonographic study in 21 patients is summarized in Table 2. No dilatation of the common hepatic duct and intrahepatic bile duct was found at follow-up in 7 of 9 patients who had cystic dilatation of the intrahepatic bile ducts at the time of radical operation. In two patients with extremely large intrahepatic cystic dilatation shown in Figure 1, however, the dilatation still remained unchanged at one year and two years after surgery, respectively. On the other hand, in all of the patients who had a fusiform dilatation of intrahepatic bile ducts at the time of operation, the dilatation was not located at the porta hepatis or inside the liver. Figure 2 presents an ultrasonogram that demonstrates persistent dilaTable 2. Results of Follow-Up Study: Postoperative Change of Intrahepatic Bile Ducts (US)
Form of Intrahepatic Bile Duct Dilatation at Operation Cystic Fusiform Total
9 12 12
Normalized 7/9 12/12 19/21 (90%)
Still Dilated 2/9 O/12 2/21 (10%)
4/5 1/5
tation of the intrahepatic bile duct two years after operation in a 9-year-old girl. The disappearance rate of radionucleotide calculated from the time-activity curve in two patients with huge intrahepatic bile duct dilatation increased from 2.2 to 3.1 and from 1.8 to 2.4, respectively (normal: 3.8 +_ 1.0). These changes indicate that biliary excretory function of these two patients improved even though the intrahepatic bile duct dilatation persisted. DISCUSSION
In 1939, McWhorter first described the association of intrahepatic bile duct dilatation with congenital dilatation of the bile duct. 7 According to additional information on this condition provided by many authors, 8'9 the incidence of intrahepatic bile duct dilatation is fairly common in patients with congenital dilatation of the bile duct. It is necessary, however, to make a clear distinction between the intrahepatic bile duct dilatation in patients with extrahepatic bile duct dilatation and that of Caroli's disease] ~ In our series of 47 patients, we evaluated the configuration of the intrahepatic bile ducts by operative cholangiograms or ERCP and found 39 cases (83%) of associated dilatation of the intrahepatic bile ducts. Our incidence of association is similar to those of other recently reported series. Approximately half of the intrahepatic bile ducts were cystic and the other half fusiform when the dilatation of the common bile duct was cystic. On the other hand, all intrahepatic bile duct dilatation was fusiform in patients with fusiform extrahepatic dilatation. It has been our policy to carry out free drainage of the bile at the porta hepatis for patients with congenital dilatation of the bile duct. We perform radical excision of the dilated extrahepatic bile duct and hepatico-jejunostomy in Roux-Y fashion as a standard surgical procedure
140
OHI ET AL
Fig 1. Operative cholangiograms of two patients demonstrating extremely large intrahepatic bile duct dilatation.
for this disease. When there is a stricture at the site of the hepatic duct, we always resect the stenotic portion and choose a more proximal dilated intrahepatic duct for the anastomosis. Since all patients have undergone the standard operation, intrahepatic dilatation of the bile ducts was not removed at the time of their operation. Considerable data is available 4'5'1~ on the postoperative follow-up of patients with congenital dilatation of the bile duct, but little work has been done to evaluate the postoperative disappearance or persistence of the intrahepatic bile duct dilatation. Several kinds of sequelae, such as frequent episodes of cholangitis, intrahepatic cholelithiasis, and cancer arising from the wall of the intrahepatic bile duct cyst could seem to be unavoidable because of the persistence of the
intrahepatic bile duct dilatation. From the results of the present study, the physical growth of patients with this disease was almost normal in spite of persistent intrahepatic bile duct dilatation. There was also no particular morbidity connected with intrahepatic bile duct dilatation. Although 23 out of 30 patients (77%) showed abnormal levels of alkaline phosphatase before operation, only 4 out of 19 patients (21%) revealed abnormal values at follow-up. Other liver function tests examined in follow-up study were within normal limits. It is concluded from these results that the intrahepatic bile duct dilatation left untreated did not exert unfavorable influences upon the postoperative course of these patients. The ultrasonographic study at follow-up revealed that the fusiform dilatation of the intra-
INTRAHEPATIC BILE DUCT DILATATION CHANGES
141
Y.T. 9y.
Preop,.
Postope.24mo.
L
P
~ V f+. Fig 2. Ultrasonograms showing the remaining dilated intrahepatic bile duct t w o years after operation in a 9-year-old girl.
hepatic bile ducts was reduced in size after free drainage at the porta hepatis. The majority of the cystic dilatation of the intrahepatic bile duct markedly decreased in size after surgery. In case of extremely large intrahepatic bile duct dilatation, the size of the duct, however, remained unchanged. Tsuchida et al ~2 reported that in 4 out of 11 tong-term survivors of this disease, intrahepatic bile duct dilatation persisted; they stressed that, also in the case of cystic dilatation, the intrahepatic bile ducts were unlikely to decrease in size after surgery. The controversy still continues as to whether intraheptatic bile duct dilatation in patients with this disease has a congenital origin or is secondary to intraluminal pressure of the intrahepatic bile ducts. On the basis of available evidence on the ultrasonographic studies at follow-up, it is reasonable to say that fusiform dilatation of the intrahepatic bile duct in case of extrahepatic dilatation is always secondary. We cannot deny, however, the possibility that a congenital developmental anomaly of the intrahepatic bile ducts
may lead to some of the cystic dilatation of the intrahepatic bile ducts. Serial evaluation of the bile excretory function estimated by hepatobiliary scintigraphy in patients with huge intrahepatic bile duct dilatation, revealed gradual improvement to almost normal levels. This indicates that persistent intrahepatic bile duct dilatation does not disturb the hepatobiliary function. As far as the surgical treatment of intrahepatic bile duct dilatation in patients with congenital dilatation of the common bile duct is concerned, hepatic lobectomy is usually limited because of the anatomical or the pathological situation of the liver. Fortunately, intractable sequelae, such as liver abscess and intrahepatic cholelithiasis resulting from the intrahepatic bile duct dilatation, were seldom encountered. Therefore, these follow-up results justify the employment of the standard operative procedure, namely excision of total extrahepatic bile duct cyst and free drainage from the porta hepatis for the treatment of this disease even if there is an
142
OHI ET AL
a s s o c i a t e d d i l a t a t i o n of t h e i n t r a h e p a t i c bile ducts. H o w e v e r , c a r e f u l a n d serial f o l l o w - u p studies a r e r e c o m m e n d e d w h e n a h u g e cystic d i l a t a t i o n of t h e i n t r a h e p a t i c bile d u c t is f o u n d at t h e t i m e of o p e r a t i o n . REFERENCES
1. Kasai M, Asakura, Y, Taira Y: Surgical treatment of choledochal cyst. Ann Surg 172:844-851, 1970 2. Ishida M, Tsuchida Y, Saito S, et al: Primary excision of choledochal cyst. Surgery 68:884-888, 1970 3. Kasai M, Suzuki H, Ohi R: Operative procedure for choledochal cyst. Jap J Surg 7:145-150, 1977 4. Flanigan DP: Biliary cysts. Ann Surg 182:635 643, 1975 5. Klotz D, Cohn BD, Kottrneier PK: Choledochal cysts: Diagnostic and therapeutic problems. J Pediatr Surg 8:271283, 1973 6. Ohkohchi N, Ohi R, Kasai M, et al: Assessment of
hepatic function after hepatic portoenterostomy for biliary atresia by the time-activity curve using 99m-Tc-EHIDA. J Jap Soc Pediatr Surg 19:631-639, 1983 (Jap) 7. McWhorter GL: Congenital cystic dilatation of the bile and pancreatic ducts. Arch Surg 38:397 411, 1939 8. Tsuchida Y, Ishida M: Dilatation of the intrahepatic bile ducts in congenital cystic dilatation of the common bile duct. Surgery 69:776-781, 1971 9. Todani T, Narusue M, Watanable Y, et al: Management of congenital choledochal cyst with intrahepatic involvement. Ann Surg 187:272-280, 1977 10. Corali J, Soupault R, Kossakowski J, et al: La dilatation polykystique cong6nitale des voies biliailes intra-h6patiques. Essai de classification. Sem H6p Paris 34:488 495, 1958 11. Kim SH: Choledochal cyst: Survey by the surgical section of The American Academy of Pediatrics. J Pediatr Surg 16:402-407, 1981 12. Tsuchida Y, Saito S, Honna T, et al: Clinical situation of intrahepatic bile duct dilatation. Shonika Mook 5:107117, 1979 (Jap)