Computational fluid dynamic (CFD) simulations of the three-dimensional flow structures in realistic cystic ducts have been performed to obtain quantitative readings of the flow parameters to compare with clinical measurements. Resin casts of real patients' cystic ducts lumen that possess representative anatomical features were scanned to obtain three-dimensional flow domains that were used in the numerical analysis. The convoluting nature of the studied cystic ducts resulted in strong secondary flow that contributed towards a dimensionless pressure drop that is four times higher than those of a straight circular tube of an equivalent length and average diameter. The numerical pressure drop results across the cystic duct compared very well with those obtained from clinical observations which indicate that CFD is an appropriate tool to investigate the flow and functions of the biliary system. From the hydrodynamic point of view, the cystic duct lumen seems to serve as a passive resistor that strives to provide a constant amount of resistance to control the flow of bile out of the gallbladder. This is mainly achieved by the coupling of the secondary flow effects and bile rheology to provide flow resistance.
One of the causes of post cholecystectomy pain is due to stone in the cystic duct. This is a very rare occurrence although it can be debilitating to the patient. We report a case of a 64 year old man presented with retained cystic duct stone post cholecystectomy complicated by liver abscess and biloma. The management of this unusual presentation is discussed.
Three-dimensional scaled-up transparent models of three human cystic ducts were prepared on the basis of anatomical specimens. The measurement of pressure drop across the cystic duct models and visualization of the flow structures within these ducts were performed at conditions replicating the physiological state. The flow visualization study confirmed the laminar nature of the flow of bile inside the cystic duct and values of pressure drop coefficient (Cp) decreased as the Reynolds number (Re) increased. The three tested models showed comparable behavior for the curve of Reynolds number versus the pressure drop coefficient. The results show that the tested cystic ducts have both increased pressure drop and complicated flow structures when compared with straight conduits. High resistance in a cystic duct may indicate that the gallbladder has to exert large force in expelling bile to the cystic duct. For patients with diseased gallbladder, and even in healthy persons, gallbladder is known to stiffen with age and it may lose its compliance or flexibility. A high resistance cystic duct coupled with a stiffened gallbladder may result in prolonged stasis of bile in the gallbladder, which is assumed to encourage the formation of gallstones.
Compression of the common bile duct by a stone impacted in the cystic duct is an uncommon cause of obstructive jaundice. We present a case study and review of the literature pertaining to the presentation, diagnosis, and surgical treatment of Mirizzi syndrome.
The cystic artery (CA) is known to exhibit variations in its origin and branching pattern. This is attributed to the developmental changes occurring in the primitive ventral splanchnic arteries. During routine dissection of a male cadaver, we observed that the CA originated from the middle hepatic artery (MHA) at a distance of about 1 cm from its origin, and the MHA originated from the right hepatic artery at a distance of 2.1 cm from its origin. The CA traversed for a distance of 1.5 cm, giving off a branch to the cystic duct. It then passed anterior to the cystic duct. The origin of the CA was located to the left of the common hepatic duct, outside the Calot's triangle. The topographical anatomy of the arterial system of the hepatobiliary region and their anomalous origin should be considered during hepatobiliary surgeries. This knowledge is also important for interventional radiologists in routine clinical practice.
We report two cases of rural Malay women in Perak, Malaysia, with extrahepatic cholangiocarcinoma and coexistent biliary ascariasis. In both cases, the narrowed bile duct may have resulted in inability of the migratory nematode to return to the gastrointestinal tract. It may be reasonable, also, to postulate that chronic biliary tract infestation by Ascaris lumbricoides may have contributed to the development of cholangiocarcinoma; a situation similar to that observed in liver fluke infestation.