DISCUSSION

The biliary complication following liver transplantation is a significant cause of

patient’s long term morbidity and mortality, and it usually deprives the patient’s quality of

life for a long time, even though most of them could be treated with non-surgical modality.

In the absence of specific contraindications, duct-to-duct anastomosis in LDLT is the choice

of biliary reconstruction in many programs nowadays, even in cases with multiple graft ducts.

The incidences of biliary complications reported in patients who underwent LDLT with

duct-to-duct reconstruction widely ranged from 8 to 60%.(Kawachi, 2002; Sugawara, 2003) Such

wide ranges of incidences of biliary complications among centers could be due to difference

in technique and experience. Also in this study, we experienced that the type of procedure

and material in duct-to-duct anastomosis was significantly associated with incidences of

biliary complication following LDLT.

There are some advantages and disadvantages in duct-to-duct biliary reconstruction

compared to bilioenterostomy in LDLT. Duct-to-duct biliary anastomosis is technically

quicker, more physiologic and anatomic, and easily accessible by endoscopic approach to

biliary system after transplantation. On the other hand, there could be two major surgical

disadvantages. One is possible tension at the anastomosis when recipient’s duct is

inappropriately prepared, and the other is size discrepancy between openings of graft’s and

recipient’s duct.

Preparation of sufficient length of recipient’s bile duct with adequate blood supply is

fundamental to perform tension-free duct-to-duct anastomosis. Because the axial arteries

from gastroduodenal artery and right hepatic artery have important role in pericholedocal

vascular network, it is necessary to minimally dissect the soft tissues around the bile

duct.(Northover, 1979) During preparation of graft’s and recipient’s ducts, arterial bleedings

from the cut end of bile ducts should be identified before duct-to-duct anastomosis. If it is

not, the bile duct should be shortened. Lee et al.(Lee, 2004) introduced a useful technique of

preparing recipient’s bile duct, the high hilar dissection, to provide sufficient length and

blood supply of recipient’s bile duct. We think this technique is very useful especially when

preparing quite a length of recipient’s bile duct or when multiple duct-to-duct anastomoses

are necessary.

Size discrepancy between graft’s and recipient’s bile ducts is another anatomical

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problem in duct-to-duct-anastomosis. Ensuring tension-free anastomosis, we preferred to

anastomose graft’s duct to recipient’s common hepatic duct because the cut end of recipient’s

intrahepatic bile ducts are usually thin and friable. According to our data, the average

diameter of partial graft duct was about 4 mm, whereas the recipient’s common hepatic duct

usually had twice the luminal diameter than the graft’s duct. To overcome this problem, the

graft duct was slid into the socket of recipient’s common hepatic duct mucosa by transmural

suture of graft’s duct and transmucosal suture of recipient’s common hepatic duct. In our

experience, this technique was useful to successfully deal with size discrepancy. But it had a

possible problem when the graft duct was too deeply slid into recipient’s common hepatic

duct so that too much redundant segment of recipient’s duct could be left around graft’s duct

(Fig. 3). That could cause collapse of graft’s bile duct and sequential bile duct obstruction.

So we recommend that the sliding depth of graft’s duct should be minimized.

Redundant segment of recipient’s duct above anastomosis site

Figure 3. A pitfall in technique of graft’s duct slid into recipient’s duct to overcome size discrepancy;

If redundant segment of recipient’s duct were left over around anastomosis site, it could compress graft’s bile duct and develop biliary obstruction. Unused segment of recipient’s bile duct should be minimized.

In this series, we used three types of suturing methods in duct-to-duct biliary

anastomosis: all interrupted, posterior wall continuous with anterior wall interrupted, and all

continuous. Between 6-0 prolene duct-to-duct anastomosis groups (Group 1 and 2), there

was no difference in the incidence of stricture and leakage. Therefore, the selection of

suturing type between all interrupted or posterior wall continuous had a little effect on the

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outcomes after duct-to-duct anastomosis. Unfortunately, we could not compare the outcomes

of all continuous sutures with the other methods because we used different sizes of needle

and thread.

However, the incidence of biliary complications was reduced after changing suture

material from 6-0 to 7-0 prolene. Especially, the incidence of biliary stricture significantly

decreased from 43% to 4.7% (P = 0.00). According to this result, the size of the suture needle

could be an important factor in duct-to-duct biliary anastomosis in LDLT.

In biliary anastomosis, there are two possible difficulties in suturing ducts; the first is

due to the direction of stitching. Putting stitches in graft duct is performed in direction from

hidden dorsal side to visible ventral side, and it is more challenging to make fine stitches on

graft’s duct than recipient’s duct. Secondly, bigger the size of suture needle, fine handling

becomes more difficult. Commonly used 6-0 sized needle has quite a length (13 mm)

compared to the size of partial graft’s duct and operative space in duct anastomosis.

Therefore, when the anastomosis is performed with 6-0 needle, it largely depends on

surgeons’ experience to achieve exact suture points at the graft duct. And frequently it could

be more deeply pointed than the surgeons’ target, which could cause narrowing of duct

lumen and technical failure in biliary anastomosis.

Using smaller suture needle in duct-to-duct biliary reconstruction has advantages in

achieving precise anastomosis. In our experience, smaller 7-0 needle was much comfortable

to stitch exact site on the graft duct than 6-0. After using 7-0 prolene suture in this study, we

experienced that the incidence of biliary stricture was significantly reduced. Using smaller

suture material allowed us to improve technical refinement in biliary reconstruction.

Many centers prefer to use 6-0 monofilament suture even nowadays for biliary

reconstruction. Although, Kyoto group reported that they recently started to use 7-0

monofilament suture, they didn’t report the outcomes of using this material.(Kasahara, 2006)

Recently, Yan et al.(Yan, 2007) reported favorable result of microsurgical technique to

biliary reconstruction of small hepatic duct with 8-0 prolene. In the future, further study with

larger number of patients using small suture material for biliary anastomosis should be

initiated to figure out the effective outcomes on reduced incidence of biliary complications.

Meanwhile, we also experienced that incidence of biliary leakage was increased after

using 7-0 prolene suture (six of 26 Group 3 patients, 23%). Fortunately, all of them were

successfully treated with endoscopic and abdominal drainage. Treating these six leakage

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patients, no major disruption of anastomosis but pinpoint leakage from biliary anastomosis

was observed. According to these findings, we concluded that the cause of bile leakage in

continuous 7-0 biliary anastomosis was not from breaking of thread due to weakness but

from partial tearing of sutured graft duct because some part was stitched too shallowly. To

solve that problem, we adopted 4- or 5-French sized external biliary stent tubing rather than

deeper pointing of stitches to the graft duct.

Our experience showed that external stent tubing was possibly able to reduce incidence

of biliary complications, especially leakage. Among patients with 7-0 continuous suture, the

incidence of biliary complication was reduced from 30.8% to 0% (P = 0.01) after using

external stent. Also we did not experience any complications related to removal of 4- or

5-French external stent. Our current preference of duct-to-duct biliary procedure in LDLT is

7-0 continuous suture with external stent. We think this procedure is feasible in duct-to-duct

biliary reconstruction to reduce incidence of biliary complication following LDLT.

However, a multicenter, prospective randomized trial in deceased liver transplantation

showed that incidence of biliary complication was significantly higher in group of patients

with T-tube biliary stenting than without. (Scatton, 2001) Ben-Ari et al.(Ben-Ari, 1998) also

didn’t recommend T-tube stenting after cadaveric liver transplantation due to high incidence

of septic complication. Also, previous studies reported bile leakage complication following

T-tube removal.(Urbani, 2002; Wojcicki, 2006)

But tube stenting in duct anastomosis is still controversial in LDLT where the bile duct

openings are usually small in size. Hong Kong group reported that duct-to-duct

reconstruction was safely performed in LDLT without biliary stent tube, reporting 24%

incidence of biliary complication.(Liu, 2004) However, Kyoto group reported slightly lower

incidence of biliary complication compared to Hong Kong group using biliary stent in right

lobe LDLT (17.6%).(Ishiko, 2002) It should be subject to large sized, prospective

randomized study to prove the effectiveness of biliary stent tubing in LDLT.

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