Anatomic variations of the intra-hepatic biliary tree in the Caribbean: A systematic review

Abstract

BACKGROUND In the classic descriptions of the human liver, the common hepatic duct forms at the confluence of left and right hepatic ducts. Many authors have documented variations in the intra-hepatic ductal system, but to the best of our knowledge there has been no report on bile duct variations in Caribbean populations. AIM To evaluate the variations in bile duct anatomy using magnetic resonance cholangiography (MRC) in unselected patients at a major hepatobiliary referral centre in the Eastern Caribbean. Knowledge of the intra-hepatic biliary anatomy is important to optimize service delivery for any physician treating liver and biliary disorders. METHODS This study was carried out at a tertiary referral hospital for hepatobiliary diseases in the Eastern Caribbean. We retrospectively evaluated magnetic resonance cholangiograms in 152 consecutive patients at this facility over a two-year period from April 1, 2017 to March 31, 2019. Two consultant radiologists experienced in MRC interpretation reviewed all scans and described biliary anatomy according to the Huang’s classification. A systematic review of published studies was performed and relevant data were extracted in order to calculate the global prevalence of each biliary variant. The variants in our population were compared to the global population. RESULTS There were 152 MRCs evaluated in this study in 86 males and 66 females. There were 109 (71.7%) persons with “classic” biliary anatomy (type A1) and variants were present in 43 (28.3%) persons. There was no statistical relationship between the presence of anatomic variants and gender or ethnicity. We encountered the following variants: 29 (19.1%) type A2, 7 (4.6%) type A3, 6 (3.95%) type A4, 0 type A5 and a single variant (quadrification) that did not fit the classification system. Compared to the global prevalence, our population had a significantly greater occurrence of A1 anatomy (71.7% vs 62.6%; P = 0.0227) and A2 trifurcations (19.1% vs 11.5%; P = 0.0069), but a significantly lower incidence of A3 variants (4.61% vs 11.5%; P = 0.0047). CONCLUSION There are significant differences in intra-hepatic biliary anatomy in this unselected Eastern Caribbean population compared to global statistics. Specifically, persons of Caribbean descent have a greater incidence of Huang A2 trifurcations and a lower incidence of Huang A3 variants.

Association between anatomic variations of extrahepatic and intrahepatic bile ducts: Do look up!

“…First of all, the present population showed very similar characteristics to those described in previous studies (Cawich et al, 2021; Cucchetti et al, 2011; Nayman et al, 2016) with “conventional” anatomy reported in 63.3% of subjects, thus confirming its representativeness of patients undergoing MRCP evaluation in tertiary centres. Moreover, the RPD joining the LHD (type 3a) was confirmed as the most common variant, followed by the trifurcation pattern (type 2).…”

“…A previous large study (Cucchetti et al, 2011) suggested a possible relation between gender and biliary anatomy, with significantly more women having biliary anomalies (45% vs 26%). However, most other reports in the literature have confuted this observation (Catalano et al, 2008; Cawich et al, 2021; Deka et al, 2014; Gupta et al, 2016; Huang et al, 1996; Song et al, 2007). Moreover, to the best of the author's knowledge, no differences have ever been observed in biliary anatomy in relation to the cause of death (Cucchetti et al, 2011).…”

“…The bile duct draining the caudate lobe usually joins the origin of the left or RHD. This “conventional” anatomic pattern has been reported in 36.7%–80% of people (Medişoğlu et al, 2020; Vidal et al, 2007), with an estimated global prevalence of 62.6% (Cawich et al, 2021).…”

“…Nonetheless, it seems that the incidence of biliary duct variations may be correlated to race and ethnicity. In fact, even if Europeans and Americans share similar prevalence rates of typical and atypical biliary anatomy (probably because both populations can be considered Caucasians), Asians seem to have a slightly higher prevalence of typical anatomy and greater occurrence of trifurcation pattern, which represents the most common variations in this population (Cawich et al, 2021; Cucchetti et al, 2011; Swain et al, 2020).…”

Robot-Assisted Common Bile Duct Exploration in Trinidad & Tobago

“…We also agree with other authors that it is important for the surgeon who wishes to undertake laparoscopic CBD exploration to have a working knowledge of biliary anatomy and variations [10,15], the ability to properly interpret intra-operative cholangiograms [16][17], an armamentarium of different approaches to duct exploration, stone extraction and closure [10,18,19], and the ability to suture laparoscopically [18,19].…”