Pitfalls and promises of bile duct alternatives: There is plenty of room in the regenerative surgery

Table 1 Differences in understanding of the clinical evidences between a surgeon and a physiologist

Clinical evidences	Understanding of a surgeon	Understanding of a physiologist
There are many negative results of the use of materials for bile duct repair	Materials associated with complications are not suitable for clinical practice	The causes of failure are what we need to determine. Can we cluster these causes to understand the underlying mechanisms? If we only consider successful cases, we will commit survival bias and be unable to determine the reasons for successful outcomes
Bile duct epithelialization never exceed the following limits: About 3 cm long and growth not more than 1-2 mm per week	We must avoid implanting grafts (autografts) longer than 3 cm. This is an interesting fact. My experience supports these values, so I am aware of the potential outcomes that may be achieved after a surgical procedure	The presence of stable values indicates the conservatism of the underlying regenerative mechanisms, which are not dependent on the surgeon’s skills or the quality of the materials
The normal human bile is not sterile and contains both living cholangiocytes and normal biliary microbiota	These are interesting facts, but we still lack the necessary tools to support endogenous regeneration in routine clinical practice. The application of cells remains unproven	The presence of living cells in bile may support the existence of unknown ways for the migration of bile duct cells. These methods need to be discovered and applied for bile duct regeneration