Secondary CBD stones may cause many clinical symptoms and signs, including abdominal pain, obstructive jaundice, cholangitis, and biliary pancreatitis [2]. Among the patients in this article, there were as many as 52 patients diagnosed with obstructive jaundice. The ideal management of this condition remains a matter of debate [5]. As far as LCBDE is concerned, the problems are mainly related to T-tube placement, such as patient discomfort, biliary peritonitis, and T-tube displacement [15, 16]. In view of this, some surgeons tried to make full use of the natural cystic duct with a microincision of the CBD or confluence followed by primary suture [10, 11]. Inspired by this, we further speculate: could we use the natural orifices comprising the cystic duct and its confluence at the CBD with no incision? Therefore, LTD-CBDE was designed for CBD exploration and stone extraction via a laparoscopic transcystic approach by dilating the confluence. Dilation of the confluence makes the insertion of the choledochoscope and stone extraction easier because it not only overcomes the problems that the cystic duct is thin and the spiral valve acts as a barrier during exploration but also enlarges the inlet diameter of the CBD to be greater than or equal to the outer diameter of the largest stone. CBD blood supply is not affected by the incision, so CBD stenosis may be prevented. The operations were performed smoothly. The success rate was 91.2% (which may be higher with careful perioperative identification of the indications), the clearance rate of CBDS was 100%, and retained stones were not identified at the postoperative follow-up.
The success rate of 91.2% with the present method coincides with that of 88.1% reported in a meta-analysis of eleven randomized trials of LCBDE [5]. By using a slightly different approach with a microincision at the confluence, Chen et al. and Niu et al reported a success rate of 100% [10, 11]. The 6 failed patients in our work were associated with anatomical problems, suggesting the importance of a carefully selected surgical strategy. Special attention should be paid to the following aspects. First, it is crucial to maintain the cystic duct intact to facilitate the incision, dilation, choledochoscope insertion, observation, stone extraction and primary closure. Second, it is important to identify the confluence correctly and avoid its damage. Finally, factors limiting the success of LTD-CBDE include anatomic features related to the cystic duct and confluence, such as fibrosis and anatomical abnormality of Calot’s triangle; small-size, atretic or tortuous duct; and low level of or posterior insertion of the cystic duct on the CBD.
The operation time reported in the literature varies widely depending on the surgical method, ranging from 104 to 194 minutes [2, 10, 17, 18]. The mean operating time was 105 minutes in our series. However, we do not think it is reasonable to directly compare the operation time because any new modality requires more operation time and is technically difficult with a clear learning curve. In the future, along with technical improvement and more effective logistic organization, the operation time will be further reduced. Patients in our series were discharged after a mean postoperative hospital stay of 5.9 days, which is not longer than other reports of mini-incision (mean 8 days) or LCBDE [5, 17, 18]. Mortality was also in accordance with the findings of other surgical modalities [10, 11]. Forty-three patients were followed up one year after the LTD-CBDE operation (25 patients lost to follow-up), and none of them presented with evidence of retained or recurrent CBDS or stenosis of CBD.
Our LTD-CBDE method is safe and effective, but a carefully selected surgical strategy should be especially emphasized, as suggested by Gigot et al. [18]. First, for patients with anatomical abnormalities or intraperitoneal adhesions, as shown in 6 patients in our series, the traditional open operation or laparoscopic choledochotomy should be performed as soon as possible. Second, despite careful suturing of the confluence with the stump wall, there were still 3 patients who suffered postoperative bile leakage. This is not higher than the incidence associated with LCBDE (5.6% with experienced surgeons vs 17.1% with inexperienced surgeons) reported by Liu et al. [19]. As analyzed by Liu et al. [19], it is clear that postoperative bile leakage (and the like) can be reduced by gaining experience in the technique [20]. Third, in our series, separation forceps, rather than balloons, were used in most patients. It is undeniable that the latter provides a quantitative and accurate degree of expansion, thus improving safety accordingly. However, Yunnan is a poor province in China, and most patients cannot afford the expensive balloon. Therefore, we chose separation forceps rather than balloons to dilate the confluence, and fortunately, the majority of patients for whom separation forceps were used to dilate the confluence successfully underwent surgery with the LTD-CBDE technique. Fourth, this is a retrospective analysis. The surgical method was selected subjectively rather than randomly, which is why we did not used the remaining 114 patients with LCBDE as a control group. Robust RCT research will be our next goal. Finally, although we hypothesized that LTD-CBDE has the potential to reduce postoperative bile duct stricture, this has not been confirmed, and further research is needed. The optimal management of CBDS depends on the skills and techniques of the surgical team available. In any case, minimally invasive or noninvasive procedures should be the direction of our efforts.