A New Technique for Reconstruction of the Common Bile Duct by an Autologous Vein Graft and a Biodegradable Endoluminal Stent

The incidence of severe bile duct injuries has significantly increased since the introduction of laparoscopic cholecystectomy. The ideal reconstruction procedure for traumatic defects of the bile duct should be technically simple and should preserve both the physiological passage of bile and the sphincter of Oddi. In this article we describe a new technique for bile duct reconstruction in a pig model by means of an autologous vein graft that is splinted by a endoluminal biodegradable polylactate acid stent. In 12 pigs the external jugular vein was removed and used as an autologous vein graft. After performing a median laparotomy a 2-cm segment was resected from the bile duct. The common bile duct was reconstructed by a venous interponate that had been endoluminally stented by a biodegradable polylactate acid stent. For the examination of stent degradation, 2 pigs were sacrificed at 3, 4, and 5 months (stent degradation group) and the remaining 6 pigs at 6 months (survival group). All the pigs in the survival group survived for 6 months before being sacrificed. After 4 months the stent material had been completely broken down and the vein graft had been relined with bile duct epithelium. Thus, this new technique for bile duct reconstruction using an autologous vein graft with an endoluminal stent is simple to perform and reliable, and constitutes an interesting alternative to bilodigestive anastomosis due to the preservation of the papilla of Vateri.     

A new technique for reconstruction of the common bile duct by an autologous vein graft and a biodegradable endoluminal stent.

The incidence of severe bile duct injuries has significantly increased since the introduction of laparoscopic cholecystectomy. The ideal reconstruction procedure for traumatic defects of the bile duct should be technically simple and should preserve both the physiological passage of bile and the sphincter of Oddi. In this article we describe a new technique for bile duct reconstruction in a pig model by means of an autologous vein graft that is splinted by a endoluminal biodegradable polylactate acid stent. In 12 pigs the external jugular vein was removed and used as an autologous vein graft. After performing a median laparotomy a 2-cm segment was resected from the bile duct. The common bile duct was reconstructed by a venous interponate that had been endoluminally stented by a biodegradable polylactate acid stent. For the examination of stent degradation, 2 pigs were sacrificed at 3, 4, and 5 months (stent degradation group) and the remaining 6 pigs at 6 months (survival group). All the pigs in the survival group survived for 6 months before being sacrificed. After 4 months the stent material had been completely broken down and the vein graft had been relined with bile duct epithelium. Thus, this new technique for bile duct reconstruction using an autologous vein graft with an endoluminal stent is simple to perform and reliable, and constitutes an interesting alternative to bilodigestive anastomosis due to the preservation of the papilla of Vateri.     

Biliary tract reconstruction using an autologous vein graft in rats

Numerous biologic and synthetic materials have been used with limited success as an interposed graft to repair segmental common bile duct (CBD) defects. The authors report here that an autologous vein graft can be successfully used to correct a CBD deficit contingent on accurate microsurgical technique immediate stenting and rapid graft vascularization. Thirty Sprague-Dawley rats underwent laparotomy and the experimental group (n=25) had a 3-mm segment of the CBD excised. The CBD defect was repaired using an interposed femoral vein graft aided by a plastic stent. The control group (n=5) had the CBD cut and repaired by means of primary anastomosis. The experimental group was subdivided into three sub-groups each examined at three different postoperative intervals: 1, 4 and 12 weeks. The results showed that inflammation was apparent in the venous wall following the first postoperative week. A progressive loss of the vascular endothelium and replacement with the columnar epithelium typical of the CBD was seen in the vein graft. Nineteen of the 25 experimental rats (76 percent) of the animals survived without complication from the surgery and there were no abnormalities in the liver biochemical tests of these animals. Any biliary tract obstruction that developed was attributed to dislocation of the stent leading to collapse of the vein graft (experimental group), or constriction of the anastomosis (control group). This study demonstrates that biliary tract reconstruction using an autologous vein graft can be successfully performed in a rat model of CBD repair. The application of this method to the clinical setting is also discussed.     

Reconstruction of bile duct lesions by an autologous vein graft and a bio-degradable endoluminal stent in an animal model: technique and clinical impact

INTRODUCTION: In this study a new treatment of bile duct lesions was investigated. A segment of the bile duct was replaced by an autologous venous interponate which had been endoluminally stented with a braided bio-degradable stent. METHODS: A total of 18 pigs (20-28 kg) was divided into three equal groups (I-III). In each group a 2 cm segment of the jugular vein was harvested. The animals in Group I (vein group, n = 6) underwent resection of a 2 cm long segment of the common bile duct which was replaced solely by the venous interponate, in Group II (stent group, n = 6) the venous interponate had been endoluminally stented by a braided bio-degradable stent. Group III (control group, n = 6) underwent only a circular mobilization of the common bile duct. Postoperatively survival rate, general condition as well as the weight were observed and checked for 6 months. During surgery and finally after sacrifice after 6 months blood and tissue samples were taken and semiquantitatively scored concerning grade of inflammation and fibrosis. RESULTS: In the stent and control group all animals survived in good condition. 3 pigs of the vein group died within 3 weeks showing signs of biliary peritonitis, another one died due to a high grade stenosis of the common bile duct with secondary biliary cirrhosis after 4 months. In the stent group all animals survived until sacrifice after 6 months. On examination the venous interponate was laminated with bile duct epithelium showing the diameter of the implanted stent. CONCLUSION: The reconstruction of bile duct lesions by a venous interponate in combination with a bio-degradable stent is easy to perform and represents a clinically interesting alternative to the biliodigestive anastomosis because of the preservation of the sphincter oddi. After 6 months the stent is completely absorbed and the venous interponate is laminated with bile duct epithelium.     

Circumferential choledochoplasties with autologous venous and arterial grafts

Circumferential choledochoplasties with vascular grafts have rarely been attempted either experimentally or in clinical practice. In this study, choledochoplasties using autologous venous and arterial grafts were performed in rats. Sixty-four rats were randomly selected into five treatment groups: A) venous interpositional graft replacement of a choledochus gap without a stent; B) venous graft with prolene stent; C) venous graft with polyethylene stent; D) arterial graft; E) a control group with simple resection between ligatures in the choledochus. The operative mortality in treatment groups B, C, D, and E, was 0, and 13% in group A. At 12 weeks follow-up, all the rats in group E had died, whereas, 52.2% (P <.05) of the rats in group A, 30% of the rats in group B, 57% of the rats in group C, and 92.8% of the rats in group D survived treatment. Surviving animals were sacrificed at 3 months for further examination. The morphology and caliber of the common bile duct of these rats were normal in 25% of the rats in group A, 33% of the rats in group B, 25% of the rats in group C, and 84.6% of the rats in group D. Proximal dilations were found in the rats presenting with abnormal morphology. The dilations were less marked in the group treated by arterial choledochoplasties. Laboratory and clinical cholestatic parameters were within normal ranges in the presence of common bile duct dilations less than four times the normal duct caliber. Electron microscopic examination of the venous and arterial graft at 3 months follow-up revealed a fibrous ring composed of collagen fibers, fibroblasts, and remnants of elastic fibers. Regenerated ductal epithelium encompassed both types of grafts. Epithelialization was more pronounced in venous grafts as compared to arterial grafts. Biliary epithelium was able to colonize the venous grafts and resume cell specialization and function as in normal biliary epithelium. The most satisfactory results were obtained using venous grafts with stents or by using arterial grafts. © 1993 Wiley-Liss Inc.     

Reconstruction of ureteral defects with microvascular vein grafts in a rat model

This study was undertaken to test the performance of an autologous vein graft as a ureteral replacement in the rat model. Twenty-six rats were divided into three groups. In Group 1 (n = 10), the animals had a 3-mm segment of the ipsilateral ureter excised and the ureteral defect repaired, using a superficial epigastric vein graft. In Group 2 (n = 10), the same ureteral defect was created and again repaired, using a superficial epigastric vein graft, with the addition of a Silastic stent. The control, Group 3 (n = 6), had the ureter transected and repaired solely by means of primary anastomosis. Animals from each group underwent urography and were sacrificed for histology at three different postoperative intervals: 1, 4, and 12 weeks. Postoperative urography results showed normal renal function in the animals with ureteral reconstruction using vein grafting aided by a stent, as well as in those with primary ureteral anastomosis. No renal function return was seen in the animals with ureteral reconstruction by vein grafting alone, without stent support. Histologically, a progressive loss of the vascular endothelium, and replacement with the urothelium typical of the ureter, was seen in the stented vein grafts. Severe ureteral obstruction at the proximal site of the graft and hydronephrosis were seen in the vein-graft group without stenting. This study demonstrates that autologous vein grafts can be used successfully to correct a ureteral deficit, contingent on accurate microsurgical technique and immediate stenting.     

Morphological Changes during Creation of a Neo-Bile Duct Using a Vein and a Biodegradable Endoluminal Stent

ABSTRACT?

Major bile duct lesions are usually treated by a hepaticojejunostomy which is often complicated by cholangitis and liver fibrosis. The aim of this study was to investigate the morphologic features of a neo-bile duct created from a vein and a biodegradable endoluminal stent. The neo-bile duct was created using a segment of the external jugular vein which was endoluminally stented by a biodegradable poly-lactate-acid stent. In 18 pigs, the common bile duct was resected and replaced by the vein with (n = 12) or without endoluminal stent (n = 6). Six animals served as controls. Survival, liver function and morphological changes of the neo-bile duct and the liver were observed for six months. After six months, the neo-bile duct morphologically resembled the native bile duct showing Ck7-positive columnar epithelium and newly formed capillaries in the bile duct wall. The biodegradable stent disappeared after four months. All animals survived and showed normal liver function and no cholestasis. In contrast, after sole vein reconstruction of the bile duct, four animals died due to biliary peritonitis and cholangitis. Creation of a neo-bile duct which morphologically resembles the native bile duct is feasible by using a body's own vein and a biodegradable endoluminal stent.     

An experimental study of bilateral repositioning of the Stensen's duct orifices with autologous vein and artery grafts in dogs.

Sialorrhoea is an indication of dysfunction in the coordination of the swallowing mechanism. Disturbance in this coordination results in excess pooling of saliva in the anterior mouth and resultant drooling. Several surgical techniques have been described for the management of sialorrhoea. In this experimental study, we planned to try a more safe and physiologic technique by repositioning of the parotid duct orifices into the glossopalatal arch, using autologous free grafts of vein and artery in dogs. Ten adult dogs were used. In each dog, both of the parotid duct orifices were included in the study. The surgical procedure involved the dissection of both parotid duct orifices and their relocation via a submucosal tunnel into the glossopalatal arch, using a vein graft for the right side and an artery graft for the left side. Functional assessment was based on the clinical observations and retrograde sialography done on the 60th day. Results were excellent. No stricture or obstruction was noted. Histological examinations done on the 90th day showed the replacement of endothelium by multilayered cubic Stensen's duct epithelium in both artery and vein grafts. There was no difference between the results of artery and vein grafts. Surgical transposition of Stensen's duct into the glossopalatal arch with autologous vein or artery graft is a safe technique which may be used in clinical cases of drooling as an alternative to the other techniques described.     

Long-term evaluation of the replacement of the trachea with an autologous aortic graft

BACKGROUND: Tracheal reconstruction after extensive resection remains a challenge in thoracic surgery. The goal of this experimental study was to analyze the long-term evolution of tracheal replacement using an autologous aortic graft. METHODS: In 21 sheep, a 5-cm segment of the cervical trachea was replaced by a segment of the descending thoracic aorta that was reconstructed to a prosthetic graft. Because of the airway collapse reported in a previous series, a permanent (n = 13) or temporary (n = 8) stent was systematically placed in the lumen of the graft. Clinical, bronchoscopic, and histologic examinations were performed up to 3 years after implantation. RESULTS: All animals survived the operation with no paraplegia. In the group with a permanent stent, three complications occurred: one stent displacement, one laryngeal edema, and one infection. Stent removal was tolerated after 6 months in the group with a temporary stent. Histologic examination showed a progressive transformation of the arterial segment into first extensive inflammatory tissue with a squamous epithelium, and after 6 to 36 months well-differentiated tracheal tissue including a continuous mucociliary epithelium and regular rings of newly formed cartilage. CONCLUSIONS: An autologous aortic graft used as a substitute for extensive tracheal replacement in sheep remained functional for periods up to 3 years. The progressive transformation of the graft into a structure resembling tracheal tissue seems to be a key factor in long-term patency. The mechanism of this regenerative process and the possibility of using arterial homografts, which would make clinical application easier, remain to be evaluated.     

低氧预适应对移植肝内胆管的显微及超微结构的影响

目的：探讨移植肝内胆管的显微和超微结构的变化以及低氧预适应的保护作用。方法：建立大鼠自体原位肝移植模型，30只SD大鼠随机分为3组，A组：自体原位肝移植组；B组：低氧预适应后行自体原位肝移植组；C组：假手术组。术后48h取材，检测各组血清胆红素水平，光学显微镜下观察各组胆管上皮细胞的显微结构，透射电子显微镜下观察肝内毛细胆管的超微结构。结果：A组血清胆红素水平比B组升高更明显（P〈0．01）；光学显微镜下，A组与B组相比，胆管上皮细胞损伤严重，细胞排列缺失明显，炎性细胞浸润增加；电子显微镜下，A组与8组相比，肝内毛细胆管管腔扩张明显，微绒毛肿胀、数量减少或消失的情况严重，胆汁淤积程度明显。结论：低氧预适应对移植肝内胆管具有显著的保护作用。     

带蒂脐静脉瓣胆道修复术与远期疗效

目的　总结带蒂脐静脉瓣胆道重建的临床经验和远期随访结果。方法　第一种术式 ,胆管上下端后壁对端吻合 ,前壁纵行切开 ,其缺损以带蒂脐静脉瓣修复 2 2例 ;第二种术式 ,胆管狭窄切开、整形 ,胆管缺损以带蒂脐静脉瓣修复 19例。结果　本组无死亡病例 ,术后达 7年以上 2 5例 ,其中再手术 3例 ,术后 7- 12年ERCP 10例 ,MRCP和双剂量静脉胆道造影各 1例 ,胆道显影均正常 ;轻度胆管炎 2例 ;另 8例无任何胆道感染症状 ,B超胆道未见异常。结论　带蒂脐静脉瓣胆道重建是一种理想的胆道修复手术。     

腹腔镜胆总管探查术置管一期缝合与T管引流的对照研究

目的:对比腹腔镜胆总管探查术中植入"胆道支撑内引流管"一期缝合与留置T管引流治疗胆总管结石的临床疗效。方法:回顾分析2010年6月至2011年10月48例腹腔镜胆总管切开探查术的临床资料。其中36例留置T管(T管组),12例留置胆道支撑内引流管一期缝合(缝合组)。对比分析两组患者年龄、性别、手术时间、术中出血量、术后住院时间及并发症等指标。结果:两组患者年龄、性别、手术时间及术中出血量差异均无统计学意义(P>0.05)。缝合组术后住院时间短于T管组。缝合组术后4例(33%)发生并发症;T管组9例(25%)发生并发症,其中1例术后胆漏,在超声引导下穿刺抽液治疗,1例胆汁培养阳性;两组并发症总体发生率差异无统计学意义(P>0.05)。缝合组于术后2周拔除胆道支撑内引流管,T管组于术后6～8周拔除T管。结论:胆道支撑内引流管在腹腔镜胆总管探查术中可代替T管起到安全减压及支撑作用,术中植入胆道支撑内引流管并一期缝合胆总管可缩短术后住院时间,提高患者生活质量。     

Portal Vein Interposition Using Homologous Iliac Vein Graft during Extensive Resection for Hilar Bile Duct Cancer

Although autologous vein grafts have been used for portal vein (PV) reconstruction after long-segment portal vein resection during surgery for hilar bile duct cancer, their procurement prolongs operation time and increases morbidity. Less is known regarding the use of homologous vein grafts. The feasibility of homografts for PV reconstruction was preliminarily evaluated in two patients who underwent curative resection for hilar cholangiocarcinoma. Both patients underwent left lobectomy, caudate lobectomy, bile duct resection, and segmental PV resection and interposition vein graft reconstruction. The iliac vein homografts were obtained from deceased organ donors and stored for 1–2 days in cold preservation solution without freezing. Neither immunosuppression nor anticoagulation was attempted. One patient has shown good PV patency for 27 months. The second patient, who had received adjuvant chemoradiotherapy, showed an asymptomatic waisting at the proximal PV anastomosis site after 4 months, which was relieved by percutaneous balloon dilatation, and has been doing well for 12 months. In conclusion, our preliminary experience with these two patients suggests that cold-stored iliac vein homografts can be considered as PV substitutes after long PV segment resection during extensive hepatobiliary surgery.     

Reconstruction of a Common Bile Duct Injury by Venous Bypass

Hepaticojejunostomy is the standard technique for the reconstruction of severe iatrogenic lesions of the common bile duct (CBD), although the technique itself is major surgery with a complication rate up to 30%. We report a case of a male patient with a iatrogenic complete transsection of the CBD. Due to multiple previous operations and the present inflammation a standard reconstruction technique was not possible to perform. A neo-bile duct was created using a segment of the Great Saphenous Vein (GSV) synchronously with an external biliary drainage by PTCA and biliary stenting (after 4 weeks). The stent was removed 8 months later. Cholangiography showed normal bile flow without occlusion. Blood tests normalised. We believe that using an autologous vein graft in combination with a removable or biodegradable stent is the right track for the reconstruction of the CBD in the future.     

胆管损伤早期内置支架并Ⅰ期修复的实验研究

目的探讨胆管损伤早期内置支架并Ⅰ期修复对术后远期胆管狭窄的预防作用及其临床应用价值。方法用36只日本大耳白兔建立胆管损伤模型，将其分为三组，A组：内置支架并Ⅰ期修复组（n=12），B组：支架拔除组（n=12），C组：单--Ⅰ期修复组（n=12）。观察手术后不同时间点各组动物血碱性磷酸酶、转氨酶及胆管壁胶原含量变化情况，并对胆管壁进行HE及Masson染色做病理学检查。结果C组在术后各时间点血碱性磷酸酶、转氨酶及胶原含量均与A组差异有统计学意义（P〈0．05）；B组术后2个月时上述指标与A组差异有统计学意义（P〈0．05）；术后4个月时差异无统计学意义（P〉0．05）。结论胆管损伤早期内置支架并Ⅰ期修复具有预防术后远期胆管狭窄的作用，但过早拔除支架可能会导致狭窄的发生。     

Repair of common bile duct injury with the round and falciform ligament after clip necrosis: case report.

Occasionally, as abdominal surgeons, we are confronted with common bile duct injury noted during video laparoscopic or open cholecystectomy. Usually this is solved by endoscopic retrograde cholangiopancreatography (ERCP) sphincterotomy and stent, or enteric bypass, suture repair and tube drainage. However, after such procedures, there is a significant number of patients with postoperative stenosis. Another alternative to repair common bile duct injury and correct postoperative stenosis is using the round and falciform ligament as circumferencial patch. Due to their closeness to the common bile duct and their adequate blood supply, they make a perfect autologous biological graft.     

大鼠肝脏胆管及门静脉铸型扫描图像分析

目的 建立大鼠去胆管肝叶和去门静脉肝叶自身对照模型,观察两肝叶之间胆管及门静脉是否存在交通支及其大体形态变化.方法 SD大鼠40只,分为S、BL、PL和BPL共4组,分别应用氰基丙烯酸酯对肝右叶胆管进行栓塞结扎制备去胆管肝叶;对肝方叶行门静脉结扎制备去门静脉肝叶.通过测量肝重/体重和方叶重/右叶重及对各组大鼠胆管和门静脉分别灌注硫酸钡明胶混悬液制备铸型标本,并运用Micro-CT扫描来观察两叶肝脏胆道和门静脉形态变化.结果 (1)大鼠手术后在本观察期内存活率达到100%,无黄疸表现.肝叶大体形态观察和两叶肝重量比指标显示,S、BL、PL组肝重/体重为3.5%,与BPL组比较差异有统计学意义(P<0.01).S、BL组方叶/右叶重量比为60%～70%,PL及BPL组则为20%左右,提示去胆管和去门脉肝叶之间的重量比差异有统计学意义(P<0.05或P<0.01).(2)Micro-CT铸型扫描可以直观地显示胆管和门静脉形态变化,未发现两个肝叶之间存在交通支或侧枝循环.结论 去胆管肝叶无明显萎缩.胆管及门静脉灌注造影显示两叶胆管及门静脉无明显的侧枝循环.Micro-CT扫描可以直观地显示胆管及门静脉形态变化,硫酸钡明胶灌注铸型为小动物肝脏Glissons系统形态学研究提供了一种借鉴方法.

Abstract：

Objective To establish a rat self-control model with the bile duct deprived (BDD) and the portal vein deprived (PVD) hepatic lobe and to observe whether there were communicated branches between the two lobes.Methods Forty SD rats were divided into four groups: group S with sham operation as an undisposed blank control, group BL with the right lobe bile duct embolized and ligated, group PL with the quadrate lobe portal vein ligated, and group BPL with the right lobe bile duct embolized and ligated and meanwhile the quadrate lobe portal vein ligated. The right hepatic bile ducts were embolized with cyanoacrylate and then ligated to prepare the BDD lobe. The portal vein of quadrate hepatic lobes was ligated as the PVD lobes. The observation period was 1 month after the bile duct or portal vein ligated. The values of liver weight/body weight and the quadrate lobe weight/the right lobe weight were recorded. The bile duct and portal vein casting specimens of these four groups were prepared by a perfusion with barium and gelatin solution. Three-dimensional micro-computerized tomography (Micro-CT) data sets were acquired to observe the morphological changes of bile duct and portal vein of the livers and whether there were communicated branches between the right and quadrate lobes in order to estimate the feasibility of the model.Results (1) The survival rate of rats after operation was 100%. No jaundice was observed. The ratio of liver/body weight in groups S, BL and PL was about 3.5%, significantly lower than that in group BPL (P<0.01). The ratio of quadrate/right lobe weight in groups S and BL was about 60%-70%, while that was about 20% in groups PL and BPL (P<0.05, or P<0.01); (2) Micro-CT images exhibited directly the morphological changes of the hepatic bile duct and portal vein, and no communicated branches or side circulation situation were observed between the two lobes.Conclusion No collateral branches were found between the two lobes and the model was successfully established. The barium casting liver specimen scanned by micro-CT provided a useful method for the morphological observation of rat liver Glissons system.     

带蒂脐静脉瓣修复Mirizzi综合征胆管缺损35例体会

目的 总结带蒂脐静脉瓣修复Mirizzi综合征胆管缺损的经验。方法 回顾性分析35例采用带蒂脐静脉瓣修复Mirizzi综合征（Ⅱ型19例、Ⅲ型15例,Ⅳ型1例）的临床资料。结果全组无死亡病例,术后发生胆漏5例,经1～3周引流后痊愈。全部病例拔管后均获6个月的随访,有27例随访达3年,未见明显胆道并发症发生。结论利用带蒂脐静脉瓣修复Mirizzi综合征胆管缺损方法简单、效果较好。     

带蒂脐静脉瓣胆道修复

目的进一步总结带蒂脐静脉瓣胆道修复的临床经验和远期随访结果。方法第一种术式，胆管上下端后壁对端吻合，前壁纵行切开，其缺损以带蒂脐静脉瓣修复21例；第二种术式，胆管狭窄切开、整形，胆管缺损以带蒂脐静脉瓣修复18例。结果本组无死亡病例。术后达7年以上25例，其中再手术3例，术后7～12年ERCP9例，双剂量静脉胆道造影1例，胆道显影均正常；轻度胆管炎2例；另10例无任何症状，B超胆道未见异常。结论带蒂脐静脉瓣胆道修复是一种理想的胆道修复手术。     

Using the Cystic Duct for Biliary Reconstruction in Dual-Graft Living Donor Liver Transplantation: A Case Report

In Taiwan, living donor liver transplant (LDLT) has accounted for the majority of liver transplantation due to organ shortage. Dual-graft LDLT is a feasible way to resolve the insufficient graft size and remnant liver in donors. We presented a heavy-weight patient underwent dual-graft LDLT, and cystic duct was used to resolve the inadequate bile duct length and limited appropriate position in dual-graft LDLT. We harvested a right lobe graft (segment 5, 6, 7, and 8 without middle hepatic vein) and a left lobe graft (segment 1, 2, 3, and 4 without middle hepatic vein) stepwise, and placed the grafts orthotopically. For proper tension and length of biliary reconstruction, we anastomosed the right intrahepatic duct of the right lobe graft to cystic duct of the recipient. Before the biliary reconstruction, the metal probe was inserted in the lumen of cystic duct in recipient to ensure the patency and destroy the Heister valve of cystic duct, then the internal biliary stent (5 Fr pediatric feeding tube) was placed in the donor's right intrahepatic duct to recipient's cystic duct and common bile duct, which allows the endoscopic removal of the internal stent. The patient has survived more than 16 months with normal liver function.