ERCP has become a preferred treatment for choledocholithiasis [3, 22]. However, there are controversies about the clinical decision of complex choledocholithiasis, especially the residual stones after choledochectomy and T-tube drainage .
Currently, experts generally believe that, after sinus maturity and the removal of T-tube, choledochoscopy possesses multiple advantages, such as convenience, less complications, lower hospitalization cost, accurate imaging diagnosis, and so on [6, 13, 17, 24]. Unfortunately, the removal of residual stones by choledochoscope requires the maturation of the T-tube sinus, which means that the T-tube needs to be indwelled for more than 6–8 weeks. However, the time of T-tube sinus maturity is too long to be tolerated by the patient . In addition, considering the possibility of residual stones during the operation period, the T-tube placed in the abdominal cavity should be thick, short, and straight in order to facilitate the successful removal of the stone in the next operation. However, the process may be considerably more challenging, requiring expert with a large professional experience.
Choledochoscopy via T-tube sinus may produce the following complications: T-tube sinus angular and blockage, drainage tube rupture causes diffuse peritonitis, biliary hemorrhage, biliary penetrance, biliary infections, acute pancreatitis, and so on. In this study, there were three patients with acute cholangitis in CDS group. Among them, two patients who have underwent choledochoscopy were converted to ERCP for successful remove stones due to T-tube sinus tract blockage. In accordance with the findings of Wang et al., T-tube sinus occlusion was successfully restored through X-ray fluoroscopy combined with soft guide wire . However, the manipulation procedure is actually quite difficult. Our study recorded that one patient in CDS- Laparoscopic groups who experienced sinus tear, hemorrhage and biliary peritonitis, was cured after symptomatic, anti-inflammatory, hemostasis and adequate drainage. At a post-operative follow-up 18 months, the patient experienced relapse. Three stones were successfully removed by ERCP.
Several caveats need to be mentioned on choledochoscopy via T-tube sinus. Liu et al. reported that there is a certain success rate and therapeutic effect in the treatment of residual stones in the common bile duct after dilatation of the duodenal papilla via T tube. When the bile duct is significantly dilated, the balloon may push the stone toward the duodenal papilla, causing the stone to escape surgery and fail . According to Zhang et al. the incidence of cholangitis induced by T-tube cholangiography is as high as 8.9% in patients with residual stones after choledochectomy. Acute obstructive suppurative cholangitis caused by obstructed drainage of the T tube or stones located in the proximal bile duct above the T tube will be fatal . In contrast, ERCP attracts people’s attention to the treatment of residual stones, because it is not limited to the maturity of the T-tube sinus.
Our retrospective study findings showed that the immediate and long-term complications rates of patients with residual choledocholithiasis treated by conventional ERCP were comparable to those previously reported in conventional cases of ERCP lithotomy. In the present study, two patients presented with bile duct retraction after T-tube drainage. The diameter of the stone is equal or greater than diameter of the lower end of bile duct. For this kind of residual stones, the stones were smoothly removed under the microscope through the balloon dilation of the bile duct opening combined with emergency lithotripsy with a mesh basket.
In addition, one patient with residual stones was completely cleared of choledocholithiasis after two ERCP treatments. During the 18th month follow-up, two patients had recurrence of stones. The recurrence of stones was considered to be related to the angle of the common bile duct, the width of the common bile duct, multiple stones, mechanical lithotripsy, and intestinal fluid reflux . Tsuchiya et al.  reported that diagnosis of minute residual stones by micro-bile duct ultrasound and removal by ERCP can reduce the recurrence of common bile duct stones. When combined with difficult cannulation in ERCP, it is worthwhile to try the guide wire through the T tube anteriorly out of the duodenal papilla, and the reverse guide incision for cannulation.
Our team retrospectively analyzed 32 patients with residual choledocholithiasis. The results showed that the ERCP stone removal treatment achieved a perfect success rate and satisfactory safety . In this study, the nasal bile duct was routinely indwelled in patients undergoing ERCP surgery. The supporting effect of the nasobiliary on the common bile duct can reduce the benign stenosis of the common bile duct caused by the removal of the T tube, especially in patients with unobvious common bile duct dilation.
ERCP stone removal treatment requires complicated endoscopic operations. During retrograde imaging, the T-tube drainage should be closed. Due to the indwelling and traction of the T tube, the common bile duct may be distorted . The guide wire may enter the T tube repeatedly when the left and right hepatic ducts are super selected. It requires the surgeon to repeatedly adjust the mirror body to retract the knife in the common bile duct through the guide wire rebound and other operations to repeatedly try super selection . For residual stones in the common bile duct with obvious dilation, the proper application of the stone basket can prevent the stones from escaping. In those patients with indwelling T-tube, the diameter of the lower end of the common bile duct may even be smaller than the diameter of the stone due to the decrease and retraction of the common bile duct pressure. At this time, blindly performing dilation of the duodenal papillary sphincter adds a risk of perforation. It is feasible to perform basket lithotripsy combined with balloon dilatation.
The indwelling nasobiliary drainage should be taken to avoid bending of the bile duct due to T tube traction . The drainage tube is placed in the left intrahepatic bile duct to fully drain and decompress the bile so that the T tube can be removed as soon as possible postoperative. T tube removal time and nasobiliary duct retention time still need to be further clinically studied in such patients after surgery in order to maximize the benefits of patients without complications such as bile leakage.
The T tube drainage time and hospital stay in the ERCP group were significantly shorter than those in the CDS group. The following reasons are considered. T-tube cholangiography was performed at one week after choledocholithotomy, and if there were residual stones in the common bile duct, ERCP surgery was performed immediately. After ERCP treatment, the opening of the duodenal papilla was opened through EST to lead to a smooth flow, and the pressure of the biliary tract was reduced. After ERCP stone removal, complications such as impaired drainage, blockage, and secondary to acute cholangitis do not need to be considered. As bile is drained and excreted normally after ERCP, the patient’s physical fitness and appetite improve and accelerate the maturation of the T-tube sinus tract.