Biliary strictures are common complications after orthotopic liver transplantation. The standard therapy for these strictures is balloon dilation followed by the insertion of stents via the ERC approach. In cases of failed ERC, PTCD approach is considered as alternative therapy. These methods are effective in most patients, but may fail in some special cases[16–17].
Firstly, the insufficiency of maneuverable devices to remove the distal intrahepatic stones through ERC approach, contribute to the failure of stone clearance, especially for widespread or large calculi. Conventional PTCD approach, which use balloon or basket to clear stones under the guidance of cholangiography, is also unable to tackle widespread and large calculi. Fortunately, a working channel for the rigid choledochoscope can be established with the aid of PTOBF. Through choledochoscope, various methods, such as constant irrigation, basket extraction and lithotripsy, can be used to eliminate calculi efficiently. In our 12 patients with hepatolithiasis, the immediate stone clearance success rate was 83.3%(10/12). With additional stone extraction via choledochoscope, all residual stones were removed. During the follow-up time, only 1 patient (8.3%) had stone recurrence with an anastomotic stricture. Reported rates of successful stone clearance via PTC approach are variable. Some studies published that the complete clearance of hepatolithiasis after percutaneous treatment were 76–85%, and the stone recurrence rate were 16–30% at a median follow-up period of 3–5 years[18–20]. Although our results may seem similar, they are not comparable as no published study has focused solely on intrahepatic calculi after liver transplantation.
What's more, it can be found in endoscopic management that balloon expansion, guidewire, ductal dilatation, and stenting cannot be placed into stenotic bile duct through the stricture when the bile duct is filled with stones or when the bile duct is too narrow or too long. For these biliary strictures, choledochoscopic needle-knife electrotomy technology, which can resolve the stricture without entering the stenotic bile duct, is a safe and effective option. As in the case of patient 12 in this study, guidewire cannot be inserted into strictured bile duct thus failed in balloon expansion and stent placement. Then, PTCD approach was performed as a rescue therapy, but failed again. Cholangiography and ERCP both showed that the stricture was a completely obstructed stricture and its length was about 6 mm. Finally, one-step PTC combined with high-frequency needle-knife electrotomy was conducted to solve this stricture and achieved stricture resolution. After the strictured opening was cut, the balloon dilatation catheter could be inserted under the guidance of guidewire(figure4).
The devices and techniques used to treat the strictures varied among studies with various outcomes. Some systematic reviews reported that patients treated with covered self-expandable metal stent(SEMS)got stricture resolution rates between 80% and 95% when the stent was left in place for 3 months or longer. In comparison, patients who received plastic stents treatment were similar with respect to stricture resolution, but SEMS required fewer interventions compared to plastic stents[22–24]. Our outcomes were consistent with those of the above studies.
In the study by Yulong et al, the feasibility and effectiveness of choledochoscopic high-frequency needle-knife electrotomy have been verified in the treatment of intrahepatic biliary stricture. After the initial electrotomy, guidewire and balloon dilatation catheter could get across the strictured bile duct in cases of serious tubular strictures which were often failed in ERC approach. Up till now, there has been no study to use this technique in treating biliary strictures after liver transplantation, thus this is the first report applying choledochoscopic high-frequency needle-knife electrotomy in biliary strictures after liver transplantation.
Unlike traditional PTC which need multiple sessions to establish a fistulous channel in several days, one-step PTC can establish a channel for a rigid cholangioscope in one operation. With the aid of PTOBF, the sinus could be expanded to a suitable size (16-18Fr)
after percutaneous biliary puncture. It can not only provide a working channel of cholangioscopy, but also a channel to insert 12Fr drainage catheter as stricture supporting.
This supporting catheter is cheap, easy to implement, and can be easily exchanged and removed. Therefore, the combination of one-step PTC and choledochoscopic high-frequency needle-knife electrotomy can provide possibility for treating complicated hepatolithiasis and refractory strictures at the same time.
As for study limitations, this work was limited by the small number of cases, and hence unable to set a control group. Besides, prospective multicenter studies involving a larger population are needed to evaluate its effects.