Pitfalls and promises of bile duct alternatives: A narrative review

Table 1 Bile duct substitute using autologous tissue

Ref.	Journal	Substitute (n)	Stent (n)	Animal type (n)	Size of BDS (cm)	Method of reconstruction of bile duct by BDS (n)	Observation period after implantation	Localization of regenerated bile duct	Causes of stenosis	Note (planned sacrificial death and epithelialization)
Shea and Hubay[15], 1948	Ann Surg	Femoral vein (21)	Vitallium tube	Dog (21)	Ring (1.5)	CBC (21)	Maximum 208 d	BDS itself	Necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	Although 14 out of 21 dogs were intentionally killed, the tissue of the regenerated bile duct was shown only as a result, and the process of bile duct regeneration was not demonstrated
Kirby and Fitts[16], 1950	Arch Surg (1920)	Jejunum (9)	T-tube	Dog (9)	Jejunum (2.5)	GBC (5); CBC (4)	Maximum 13 mo	BDS itself	BDS stenosis was not observed when the T-tube was inserted	Seven out of nine dogs were intentionally killed; however, no epithelial regeneration was observed at the anastomotic site. The procedure was too complicated
Pearce et al[10], 1951	Ann Surg	Femoral vein (32)	Lord and blakemore tube	Dog (32)	Ring (1.0)	CBC (10); CBJ (20); GBC (2)	Maximum 6 mo	BDS itself	Necrosis of autologous tissue, narrowing of the lumen of autologous tissue, narrowing of the anastomosis with the native bile duct, necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	Only 1 of the 32 dogs survived for more than 6 mo. It was investigated in 32 dogs; however, in the end, fibrosis of the vein and stenosis of the anastomotic site with the native site occurred, and bile duct epithelial regeneration was not observed. It was concluded that the vein was not suitable for BDS
Ulin et al[17], 1955	Ann Surg	Vascularised jugular vein (10)	Polyethylene tube	Dog (10)	Ring (2.0-5.0)	CBC (10)	Maximum 10 mo	BDS itself	Necrosis of autologous tissue, narrowing of the lumen of autologous tissue, narrowing of the anastomosis with the native bile duct, necrosis of BDS itself, narrowing of the lumen of BDS, and narrowing of the anastomosis with the native bile duct	The omentum was used to maintain blood flow to the BDS, but in some cases, it functioned as a BDS only during the period when the stent was in place (6 out of 10 dogs). Bile duct regeneration process was not studied. No regeneration of the bile duct epithelium was observed
Myers et al[18], 1960	Ann Surg	Femoral vein and artery, bile duct (17), and homologous bile duct (6)	Polyethylene tube	Dog (28)	Ring (unknown)	CBC (23)	Maximum 449 d	BDS itself	Necrosis of autologous tissue, narrowing of the lumen of autologous tissue, narrowing of the anastomosis with the native bile duct, necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	BDS using autologous veins, arteries, or allogeneic arteries also narrowed shortly after transplantation. No bile duct epithelial regeneration was observed
Dunphy and Stephens[19], 1962	Ann Surg	Autologous vein and artery (20), and homologous artery (32)	T-tube	Goat (44), dog (8)	Ring (1.0)	CBC (52)	Maximum 9 mo	BDS itself	Necrosis of autologous tissue, narrowing of the lumen of autologous tissue, narrowing of the anastomosis with the native bile duct, necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	In an experiment using autologous veins and T-tube as BDS, 2 dogs survived for more than 6 mo; however, both dogs demonstrated dilation of the bile duct on the liver side. No bile duct epithelial regeneration was observed
Belzer et al[44], 1965	Ann Surg	Femoral vein (20)	T-tube	Goat (20)	Patch (3.0-4.0)	Patch (20)	Maximum 11 mo	BDS itself	Necrosis of autologous tissue, narrowing of the lumen of autologous tissue, narrowing of the anastomosis with the native bile duct, necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	Only 3 out of 20 dogs were intentionally killed, but no good bile duct epithelial regeneration was observed
Lindenauer and Child[47], 1966	Ann Surg	Vascularized jugular vein (14)	(-)	Dog (14)	Ring (unknown)	CBC (14)	Maximum 18 mo	BDS itself	The omentum increased blood flow to the BDS; however, it resulted in scar contraction. Necrosis of BDS itself, narrowing of the BDS lumen, and narrowing of the anastomosis with the native bile duct	No dog survived for more than 3.5 mo, although the omentum was used to maintain BDS blood flow
Palmes et al[48], 2009	J Invest Surg	External jugular vein (18)	PLA stent (12)	Pig (18)	Ring (2.0)	CBC (18)	Maximum 6 mo	BDS itself	When the stent was not inserted, the BDS was necrotic. When the stent was inserted, the BDS lumen was preserved, but eventually, it became necrotic and narrowed	Of the 18 dogs, all 12 stented dogs were deliberately killed. However, the process of regeneration of veins into the bile duct was not reported
Liang et al[49], 2012	World J Gastroenterol	Omentum (8)	Bioabsorbable stent	Pig (8)	Ring (0.5-1.0)	CBC (8)	Maximum 4 mo	BDS itself	The BDS lumen was preserved when the stent was inserted	The bile duct defect was repaired with an omentum, which was similar to inserting a T-tube into the defect. Bile duct regeneration was also poorly demonstrated

BDS: Bile duct substitute; CBC: Common bile duct to bile duct substitute to common bile duct; CBJ: Common bile duct to bile duct substitute to jejunum; GBC: Gallbladder to bile duct substitute to common bile duct; PLA: Polylactide acid.

Table 2 Bile duct substitute using non-bioabsorbable material

Ref.	Journal	Substitute (n)	Stent	Animal type (n)	Size of BDS (cm)	Method of reconstruction of bile duct by BDS (n)	Observation period after implantation	Localization of regenerated bile duct	Causes of stenosis	Note (planned sacrificial death and epithelialization)
Dunphy and Stephens[19], 1962	Ann Surg	Teflon (8)	(-)	Dog (4), goat (4)	Ring (1.0)	CBC (8)	Maximum 7 wk	BDS outside	Narrowing of the anastomosis with the native bile duct; narrowing of the lumen of BDS	In all cases, the hepatobiliary enzyme levels increased, and no survivors were observed for more than 7 wk after transplantation
Bergan et al[20], 1962	Arch Surg	Vascularized polyvinyl sponge (21)	(-)	Dog (21)	Ring (0.5)	CBC (21)	Maximum 14 mo	BDS outside	Narrowing of the anastomosis with the native bile duct; narrowing of the lumen of BDS	Four out of 21 dogs survived for > 60 d after transplantation, and four of them had stenosis of BDS
Sherman et al[21], 1963	Ann Surg	Acrylamide with Dacron (33)	(-)	Dog (33)	Ring (1.5-3.5)	CBC (33)	Maximum 31 mo	BDS outside	Narrowing of the anastomosis with the native bile duct; narrowing of the lumen of BDS	Twenty-six out of 33 dogs died within 3 mo. In all cases, fibrotic thickening around the BDS and severe scar contraction had occurred at the site of anastomosis
Mendelowitz et al[22], 1982	Am J Surg	Gore-Tex (6), dacron (2)	(-)	Dog (8)	Ring (2.0-3.0), patch (2.0 cm × 1.0 cm)	Patch (Gore-Tex) (2), CBJ (Gore-Tex) (2), CBC (Gore-Tex) (1), CBC (Dacron) (2), GBJ (Gore-Tex) (1)	Maximum 40 d	BDS outside	Narrowing of the anastomosis with the native bile duct; narrowing of the lumen of BDS	In all cases, a bile plug was found in the lumen of the BDS, and a high degree of fibrotic thickening was found around the site of anastomosis
Gómez et al[23], 2002	J Gastrointest Surg	Gore-Tex (12)	(-)	Dog (12)	Ring (2.0-3.0)	CBC (12)	Maximum 3 mo	BDS outside	Narrowing of the lumen of BDS	Eleven out of 12 dogs were intentionally killed, but severe fibrotic thickening was observed around the BDS

BDS: Bile duct substitute; CBC: Common bile duct to bile duct substitute to common bile duct; CBJ: Common bile duct to bile duct substitute to jejunum; GBJ: Gallbladder to bile duct substitute to jejunum.

Table 3 Bile duct substitute using bioabsorbable material

Ref.	Journal	Substitute	Stent	Animal type (n)	Size of BDS (cm)	Method of reconstruction of bile duct by BDS (n)	Observation period after implantation	Localization of regenerated bile duct	Causes of stenosis	Note (planned sacrificial death and epithelialization)
Rosen et al[24], 2002	Surgery	SIS	(-)	Dog (15)	Patch: (2.0 cm × 1.0 cm), ring: (2.0-3.0)	Patch (9), CBC (6)	Maximum 5 mo	BDS itself	Scar contraction at the site of anastomosis on the duodenal side	Thirteen out of 15 dogs were intentionally killed. The regenerated bile duct tissue was shown consequently, and the process of regenerating the bile duct was not shown
Miyazawa et al[25], 2005	Am J Transplant	P (CL/LLA) with PGA	(-)	Pig (18)	Ring (3.0)	CBJ (18)	Maximum 6 mo	BDS outside	No narrowed BDS	All pigs were intentionally killed. A good bile duct regeneration process was shown
Nau et al[26], 2011	HPB (Oxford)	PGA and TMC	5 Fr pancreatic stent	Dog (11)	Ring (1.0)	CBC (11)	Maximum 12 mo	BDS itself	Narrowing of the BDS lumen	Ten out of 11 dogs were intentionally killed. No good bile duct epithelial regeneration was observed
Li et al[27], 2012	Biomaterials	Collagen with bFGF	(-)	Pig (26)	Patch (2.0 cm × 1.0 cm)	Patch (26)	Maximum 6 mo	BDS itself	No narrowed BDS	All pigs were intentionally killed. The regenerated bile duct tissue was shown consequently, while the process of regenerating the bile duct was not shown
Tao et al[28], 2015	Artif Organs	Collagen	Plastic stent	Pig (20)	Patch (2.0 cm × 0.6 cm)	Patch (12)	Maximum 12 wk	BDS itself	No narrowed BDS	All pigs were intentionally killed. The regenerated bile duct tissue was observed consequently, while the process of regenerating the bile duct was not shown
Tanimoto et al[62], 2016	Langenbecks Arch Surg	P (CL/LLA)	T-tube	Pig (11)	Ring (2.0)	CBC (11)	Maximum 6 mo	BDS itself	No narrowed BDS	All pigs were intentionally killed. A high degree of fibrosis was observed in the regenerated bile duct tissue
de Abreu et al[63], 2020	J Biomater Appl	Bacterial cellulose film	T-tube	Pig (10)	Patch (2.0 cm × 1.0 cm)	CBC (20)	Maximum 330 d	BDS itself	No narrowed BDS	All pigs were intentionally killed. No process of bile duct regeneration was shown

BDS: Bile duct substitute; bFGF: Basic fibroblast growth factor; CBC: Common bile duct to bile duct substitute to common bile duct; CBJ: Common bile duct to bile duct substitute to jejunum; P(CL/LLA): Polyε-caprolactone/poly l-lactide; PGA: Polyglycolic acid; SIS: Small intestinal submucosa; TMC: Trimethylene carbonate.