JDDH Journal

1.      Introduction

The anatomy of the bile duct (BD) is resembling that of the portal system and liver segments. Based on the literature, the proportion of biliary anatomical variations varies between 28% and 43%. Most of hilar bile ducts anatomical variations stem from different Right Posterior Sectional Bile Duct (RPSBD) origin [1,2].

Shimizu's operative series showed that the RPSBD is most commonly supraportal in 84%, infraportal in 13% and rarely combination in 3% (the segment VII duct supraportal and segment VI infraportal) [3]. Furthermore, Nakamura's operative series report the supraportal RPSBD to be most common in BD variant type I (65%, the classic form where the RPSBD and the anterior sectional BD join to form a single right hepatic duct), type II (9.2%, the RPSBD joins the confluence, forming trifurcation) and type IV (15.8%, the RPSBD joins the left hepatic duct), whereas, the infraportal RPSBD as type III (8.3%) and the combination as type V (1.7%) [4].

Recognition of the hump appearance in animal cholangiogram to be due to supraportal upward course of the RPSBD was first by Hjortsjo Crooks in 1951 [5].  The sign can be positive for the supraportal type BD the classic Nakamura type I, II or type IV. Recognition of the Hjortsjo's Crook sign (HCS) in ERCP can enrich our preoperative knowledge of biliary anatomical variation, their precise delineation and anticipation for technical modifications to achieve safe curative liver resection [3], transplantation [4,6-8]and to avoid biliary injury in common general surgical procedure like cholecystectomy [9-11].

Our study describes the characteristics of HCS of the RPSBD anatomy in relation to the right portal vein (RPV) among Saudi population using ERCP cholangiogram. To date, the relation of the different anatomical variation of the RPSBD to the RPVbased on HCS never been examined before in human.

2.      Materials and Methods

3.1 Patients and methods

This prospective study carried out during the period from March 2010 to January 2015. We prospectively included 237 consecutive patients undergone ERCPs full filling the inclusion criteria with age range 18-90 years old.  Relevant demographic and laboratory data obtained and depicted in table 1 and 2. Patients with complete imaging study and without any prior history of liver resection or biliary instrumentation were considered as inclusion criteria, while criteria like, incomplete study, previous liver surgery and previous liver transplantation were considered as exclusion criteria.The ERCP cholangiogram was reviewed by two radiologists separately. Further filling and focused image in ERCP done if needed during the procedure. The anatomy is interpreted by two different radiologists.

2 Statistical analysis

Data analyses included descriptive statistics computed for continuous variables, including means, standard deviations (SD), minimum and maximum values as well as 95% CI. Frequencies were used for categorical variables. In this study, no attempt at imputation for missing data. For all tests, significance is defined as p<0.05 (95% confidence interval). All statistical analyses done using SPSS 12 (Chicago, Illinois, USA).

3.      Result

The patient’s demography data shown in Table 1. There were significant differences between the two groups in term of age but not gender at the time of ERCP. Likewise, minor laboratory difference between the two groups but not clinical difference in all biochemical profiles between Saudi and Non-Saudi population as depicted in Table 2.

Positive HCS was detected more frequently among patients with Type I RPSBD anatomy in both Saudi and non-Saudi, 16 (8%) and 4 (10.5) respectively. The second commonest occurrence of positive HCS in Saudi were found in type II RPSBD variant, in 13 (6.5%) patients. On the other hand, only 2 (1.5%) Saudi and 1 (2.6%) non-Saudi patients were detected with type-III had positive HCS. The presence of positive of HCS in both groups depicted intable 3. Clearly showed the difference between the two groups is not significant.

4.      Discussion

Knowledge of details hepatobiliary anatomy is vital while performing complex surgical procedures such as liver transplant or hepatobiliary surgeries. This is particularly important especially when it comes to anatomic areas with high rates of variations. Multiple biliary orifices in hilar transection plane requiring complex reconstruction are as common as 26% in Ohkubo's and 39.6% in Kasahara's operative series, requiring hilar dissection [1,6]. Hence, the extensive pre-operative imaging studies to determine the bile ducat anatomical variant is of paramount.

In typical biliary duct course, the lateral hepatic bile duct supplying segments VI and VII and the paramedian hepatic bile duct supplying segments V and VIII re-unite to form the right hepatic bile duct (RHD). However, it has been reported that only 57% cases are found to be associated with this kind of modal disposition[12]. Many anatomic variationsof the convergence of biliary ducts are reported, where the RHD may join the main hepatic duct below the normal confluence level (anterior region in 9% cases and posterior region in 16 % cases). However, there are situations where the right anterior and posterior segmental bile ducts do not form the right hepatic duct and 6% to 9% of the cases the right anterior segmental duct joins the left hepatic duct while in 7% to 14% of the cases the anterior segmental duct joins the hilar confluence and forms and three-branch type hilar confluence (c), similarly 9% to 27% cases, the posterior segmental duct joins the left hepatic duct [12-14].

To determine the specific anatomical variations, various studies have been conducted using different modalities like cadaveric research [15], intraoperative cholangiogram [16,17] or imaging such as ultrasonography [18] and magnetic resonance cholangiography [19,20]. On the other hand, ERCP is the standard technique in this field, provides if done properly, a detailed anatomy of the extrahepatic and the intrahepatic biliary anatomy as well [21]. The ERCP procedure was used in this study to document the variant biliary anatomy and the RPSBD and to investigate the usefulness of positive HCS in delineation patterns of the RPSBD in relation to right postal vein as demonstrated in cholangiogram obtained through ERCP.

Due to expansion and advancement in surgical intervention in hepatobiliary conditions and transplant this area has moved from anatomy books and being an area of clinical research to practical needs [22]. Previous studies dealt with patients from the West or the Far East area and have reported anatomic variants of hepatobiliary system detected by intraoperative cholangiography, MRCP (magnetic resonance cholangiography), or ERCP [23-26]. To our knowledge, this is the first study to examine the relationship between HCS and the various patterns of the RPSBD variable anatomy in human. We looked at the delineation patterns of the RPSBD in relation to the HCS in patients with hilar images in ERCP applied on 237 consecutive patients and in relation to Hjortsjo crook sign presence and this can be taken to represent a sample of the Saudi population.

Among all variant types of RPSBD, we found that, HCS was more frequently found in type-I RPSBD anatomy in Saudi AND non-Saudi and were 8% (16/199) vs 10.5% (4/38) so the differences were not significant. Type 2 RPSBD anatomy is the second most common anatomical variant with frequent positive sign in Saudi and non-Saudi, 6.5% (13) vs 5.3 (2/38) respectively.  We did encounter low incidence of type-III HCS, in which the RPSBD drains into the common bile duct (table 3). Incidence of this anatomic variation has been reported before as ‘cysticohepatic ducts’ and its prevalence is very low (1–2%). Our observation is consistent with other studies that reported only 2% of the cases the RPSBD drained into the cystic duct. Another report revealed only 1% cholangiograms depicted an anomalous RHD, which emptied into the cystic duct.   Prior information on HCS will help in dealing with the anatomical abnormality especially in the context of RPSBD, where the cystic duct can be ligated between the gallbladder and the point at which the duct joins [27,28].

Likewise, avoiding biliary complications for both donor and recipient in Living donor liver transplantation (LDLT) is critical to achieve safety for both. One of the major biliary complications in patients undergoing LDLT is the anatomical limitations contributed by multiple tiny bile ducts and the differential blood supplies. Recognizing these anomalies with aid of HCS preoperatively, this may result in dramatic drop in the incidence of biliary complications and improve outcome and selection of donors in LDLT in Saudi populations.

A limitation of this study was that it did not evaluate the patterns of HCS in a healthy population [29]. This study included patients without any prior history of liver resection or biliary instrumentation.

Irrespective of that, our data may be more representative of the general Saudi population than data from other populations obtained in carefully selected liver donors.

In conclusion, our study reveals that type-I and type II RPSBD anatomical variation is more commonly to show positive HCS in Saudi patients than any other type. Prior knowledge of this sign is essential to achieve curative resection in some cases with an abnormal pattern of the RPSBD. Since elusive knowledge of the biliary anatomy at hepatic hilum in hepatobiliary surgery may easily lead to postoperative biliary complication [4,8], preoperative recognition as well as intraoperative understanding of the RPSBD is apparently important for safe and curative resection in patients with aberrant biliary system. Although biliary complications after LDLT continue to be challenging, to obtain a more favorable outcome, proper evaluation of HCS may contribute as a significant factor in the pathophysiological mechanisms of biliary complications in LDLT. In addition, when left-sided hepatectomy is indicated in patients with HCS, diagnosis of the confluence patterns of the RPSBD may be clinically useful, and should be well-recognized by biliary surgeons.

Table 1: Patient Demography

1. Ohkubo M, Nagino M, Kamiya J, Yuasa N, Oda K et al. (2004) Surgical anatomy of the bile ducts at the hepatic hilum as applied to living donor liver transplantation. Ann Surg 239: 82-86.
2. Puente SG, Bannura GC (1983) Radiological anatomy of the biliary tract: variation and congenital abnormalities. World J Surg 7: 271–6.
3. Shimizu H, Sawada S, Kimura F, Yoshidome H, Ohtsuka M et al. (2009) Clinical significance of biliary vascular anatomy of the right liver for hilar cholangiocarcinoma applied to left hemihepatectomy. Ann Surg 249: 435-439.
4. Nakamura T, Tanaka K, Kiuchi T, Kasahara M, Oike F, Ueda M (2002) Anatomical variations and surgical strategies in right lobe living donor liver transplantation: lessons from 120 cases. Tranplantation 73: 1896-1903.
5. HJORTSJO CH (1951) The topography of the intrahepatic duct systems. Acta Anat (Basel) 11: 599-615.
6. Kasahara M, Egawa H, Tanaka K (2005) Variations in biliary anatomy associated with trifurcated portal vein in right-lobe living-donor liver transplantation. Transplantation 79: 626-627.
7. Huang TL, Cheng YF, Chen CL, Chen TY, Lee TY (1996) Variants of the bile ducts: clinical application in the potential donor of living-related hepatic transplantation. Transplant. Proc. 28:1669-70.
8. Cheng YF, Huang TL, Chen CL, Chen YS, Lee TY (1997) Variants of the intrahepatic bile ducts: application in living-related liver transplantation and splitting liver transplantation. Clin. Transplant.11: 337-40.
9. Christensen RA, VanSonnenberg E, Nemcek AA, D’Agostino HB (1992) Inadvertent ligation of the aberrant right hepatic duct at cholecystectomy: radiologic diagnosis and therapy. Radiology. 183:549–53.
10. Lillemoe KD, Petrofski JA, Choti MA, Venbrux AC, Cameron JL (2000) Isolated right segmental hepatic duct injury: a diagnostic and therapeutic challenge. J Gastrointest Surg. 4:168-77.
11. Turner MA, Fulcher AS (2001) The cystic duct: normal anatomy and disease processes. Radiographics 21: 3-22.
12. Couinaud C. Le foie. Etudes Anatomiquesetchirurgicales, Edition Masson. 1957.
13. Healey JE Jr, SCHROY PC (1953) Anatomy of the biliary ducts within the human liver; analysis of the prevailing pattern of branchings and the major variations of the biliary ducts. AMA Arch Surg 66: 599-616.
14. Gazelle GS, Lee MJ, Mueller PR (1994) Cholangiographic segmental anatomy of the liver. below Radiographics 14: 1005-1013.
15. Kune GA (1970) The influence of structure and function in the surgery of the biliary tract. Ann R Coll SurgEngl 47: 78-91.
16. Hamlin JA (1981) Biliary ductal anomalies. In: Berci G, Hamlin JA, eds. Operative Biliary Radiology, 1st edn. Baltimore: Williams & Wilkins. 110–16.
17. Choi JW, Kim TK, Kim KW, Kim AY, Kim PN, et al. (2003) Anatomic variation in intrahepatic bile ducts: an analysis of intraoperative cholangiograms in 300 consecutive donors for living donor liver transplantation. Korean J Radiol 4: 85-90.
18. Zheng RQ, Chen GH, Xu EJ (2010) Evaluating biliary anatomy and variations in living liver donors by a new technique: three-dimensional contrast-enhanced ultrasonic cholangiography. Ultrasound Med Biol. 36: 1282–1287.
19. Mortel´e KJ and Ros PR (2001) Pictorial essay. Anatomic variants of the biliary tree: MR cholangiographic findings and clinical applications. American Journal of Roentgenology. 177:89–394.
20. Aube C, Tuech JJ, Delorme B (20040 Contribution of magnetic resonance cholangiography to the anatomic study of bile ducts. Hepato-Gastroenterology.51:1600–4.
21. Gulliver DJ, Cotton PB, Baillie J (1991) Anatomic variants and artifacts in ERCP interpretation. AJR Am J Roentgenol 156: 975-980.
22. Kiuchi T, Okajima H (2003) Anatomical variants and anomalies. In: Tanaka K, Inomata Y, Kaihara S. ed. Living-donor liver transplantation: surgical technique and innovations. Barcelona, Spain: Prous Science, pp 17.(book)
23. Kida H, Uchimura M, Okamoto K (1987) Intrahepatic architecture of bile and portal vein (in Japanese). Tan to Sui (J Biliary Tract and Pancreas).8:1–7.
24. Ishiyama S, Yamada Y, Narishima Y, Yamaki T, Kunii Y, et al. (1999) Surgical anatomy of the hilar bile duct carcinoma (in Japanese). Tan to Sui (J Biliary Tract and Pancreas). 20:811–29.
25. Lee CM, Chen HC, Leung TK, Chen YY (2004) Magnetic resonance cholangiopancreatography of anatomical variants of the biliary tree in Taiwanese. J. Formos Med Assoc103: 155-9.
26. Kim HJ, Kim MH, Lee SK (2002) Normal structure, variations and anomalies of the pancreaticobiliary ducts of Koreans: a nationwide cooperative prospective study. Gastrointest. Endosc.55: 889-96.
27. Champetier J, Létoublon C, Alnaasan I, Charvin B (1991) The cystohepatic ducts: surgical implications. below SurgRadiolAnat 13: 203-211.
28. Reid SH, Cho SR, Shaw CI, Turner MA (1986) Anomalous hepatic duct inserting into the cystic duct. AJR Am J Roentgenol 147: 1181-1182.
29. Freeman ML, Nelson DB, Sherman S, Haber GB, Herman ME, et al. (1996) Complications of endoscopic biliary sphincterotomy. N Engl J Med 335: 909-918.