Current trends in the treatments of choledochal cysts in pediatric patients in Korea in the era of minimally invasive surgery: narrative review
Article information
Abstract
Choledochal cyst (CC) is a rare biliary tract disease characterized by cystic dilation of the biliary duct that requires surgical resection because of its malignant potential and associated complications. Minimally invasive surgeries (MIS), such as laparoscopy and robotics, have been increasingly used for the treatment of CC. This study investigated the current treatment trends and outcomes of pediatric CC in Korea, with a focus on MIS. We reviewed papers and conference abstracts on pediatric CC in Korea, published between 2000 and 2024. The incidence of CC in Korea is similar to that in Japan, with a rate of 1 in 13,000 individuals and a male-to-female ratio of 1:3 to 1:4. Type I CC was the most common (73.8%), followed by type IVA (16.0%). The first pediatric laparoscopy for CC in Korea was performed in 2006, and the first robotic surgery was in 2011. According to national surveys conducted by the Korean Association of Pediatric Surgeons in 2002 and 2017, all surgeries performed in the 2000s were open procedures. By the late 2010s, 54.3% of surgeries had been performed using MIS (laparoscopy, 31.1%; robotic surgery, 23.2%). Although few institutions have reported MIS outcomes for CC in Korea, laparoscopic surgery has been shown to be safe and cosmetically favorable. The surgical outcomes of robotic surgery are similar, but with challenges such as longer operation times, difficulties in small patients, and higher costs. Although laparoscopic surgery is currently the standard treatment in Korea, robotic surgery may become another standard procedure if the technological limitations can be overcome.
INTRODUCTION
Choledochal cyst (CC) is an uncommon biliary tract disease characterized by cystic dilation of the biliary duct. Surgical resection is often required because of the high risk of malignancy and related complications [1,2].
Historically, open laparotomy has been performed in most CC surgeries. However, minimally invasive surgeries (MIS), such as laparoscopy and robotic surgery, have developed rapidly and are now being increasingly applied for the treatment of CC [3-6].
This study investigated the disease characteristics, treatment principles, and current treatment trends of pediatric CC in Korea with a focus on MIS. Furthermore, we analyzed the advantages and disadvantages of laparoscopic and robotic surgeries and explored their outcomes in Korea to determine the optimal treatment strategy for pediatric CC.
GENERAL CHARACTERISTICS OF CC
1. Epidemiology
The incidence of CC is known to be higher in East Asia. Although no precise statistics are available for Korea, the incidence is similar to that in Japan, at approximately 1 per 1,000 hospital admissions or 1 in 13,000 individuals. In contrast, the incidence in Western countries ranges from 1 in 100,000 to 1 in 150,000 individuals [7,8]. CC occurs more frequently in females, with a male-to-female ratio of 1:3 to 1:4, and more than 60% of cases occur in children under 10 years of age [8,9].
2. Pathogenesis
The pathogenesis of CC remains unclear, but various theories have been proposed to explain it. Currently, the long common channel theory related to anomalous union of the pancreatic and biliary ducts (AUPBD) is the most widely accepted. The persistent reflux of pancreatic enzymes into the biliary tract caused by AUBPD damages the bile duct wall, leading to dilatation. Other popular theories, such as in utero accidents or acquired defects, do not support these observations [8,10].
3. Classification
The first classification of CC was proposed by Alonso-Lej and colleagues. Subsequently, Komi and colleagues proposed a new classification system based on AUPBD type [7]. Recently, the Todani classification has become widely accepted worldwide, including Korea [10,11]. The Todani classification is as follows: type I consisting of 1) cystic, 2) saccular, or 3) fusiform, dilatation of the extrahepatic biliary tree, is the most common form. Type II refers to an extrahepatic biliary diverticulum. Type III, also known as choledococele, is a cystic dilation of the intraduodenal portion of the extrahepatic biliary tree. Type IV consists of type IVA, characterized by multiple dilatations of the intrahepatic and extrahepatic biliary trees, and type IVB, consisting multiple cystic dilatations of the extrahepatic biliary tree. Type V, known as Caroli’s disease, shows multiple dilatations of the intrahepatic bile ducts (Fig. 1) [8,10,11].
The Todani classification for choledochal cyst. Type I, 1) cystic, 2) saccular, or 3) fusiform dilatation of the extrahepatic biliary tree. Type II, an extrahepatic biliary diverticulum. Type III (choledochocele), a cystic dilatation of the intraduodenal portion of the extrahepatic biliary tree. Type IVA, multiple dilatations of intrahepatic and extrahepatic biliary trees. Type IVB, multiple cystic dilatations of the extrahepatic bile duct. Type V (Caroli’s disease), multiple dilatations of the intrahepatic biliary trees.
According to two national surveys conducted by the Korean Association of Pediatric Surgeons (KAPS) in 2002 and 2017, type I was the most common type, accounting for 71.3% and 73.8% of cases, respectively, followed by type IVA at 27.2% and 16.0%, respectively [3]. These figures are similar to those reported previously.
PRINCIPLE OF TREATMENT FOR CC
Previously, enteric drainage of the cyst was performed. However, drainage without cyst excision via cyst-enteric anastomosis can lead to biliary stasis and recurrent infections [8]. Owing to AUPBD, persistent reflux of pancreatic enzymes into the biliary tract causes recurrent inflammation, leading to hyperplasia and metaplasia of the epithelium and increasing the risk of malignant transformation [10,12]. Therefore, in cases of types I and IV CC, which are probably caused by AUPBD, complete resection of the extrahepatic bile duct and cyst excision is required [7,8,10]. The reported malignant potentials of type II and type III CC are extremely low. Diverticulectomy and primary common bile duct closure of the diverticular neck are generally performed in type II cases. In type III cases, endoscopic sphincterotomy or transduodenal excision is performed, depending on the size of the choledococele. Liver resection or transplantation is recommended for patients with type V disease [7].
MIS FOR CC IN PEDIATRIC PATIENTS IN KOREA
To investigate the status of MIS for CC in Korea, we reviewed the published papers and conference abstracts. MEDLINE and KoreaMed were searched using the terms ‘choledochal cyst’, ‘laparoscopic’, ‘robotic’, and ‘children’ from January 2000 to December 2023. Abstracts from the annual congresses of the Korean Surgical Society from 2011 to 2023 and the KAPS from 2014 to 2024 were also included. Among the retrieved studies, those addressing CC in Korean children were selected. We also reviewed the references of articles that specifically addressed CC in Korean children. The reviewed studies are summarized in Table 1.
Reported investigations on the treatment of choledochal cyst in Korea
Previously, open laparotomy was the mainstream surgery for CC. In 1995, Farello et al. [13] performed the first successful laparoscopic CC surgery, total CC excision, and Rouxen-Y hepaticojejunostomy. The first pediatric laparoscopic CC surgery in Korea was performed in a 17-year-old girl in 2006, which was reported with 11 adult patients [1]. Several studies have reported laparoscopic CC surgery in pediatric patients [14]. The first robotic surgery for CC performed by Chang et al. [15] in 2011 was followed by additional reports. According to two national surveys conducted by the KAPS in 2023, all surgeries were performed using open procedures in the 2000s. By the late 2010s, the proportion of open surgeries had decreased to 42.3%, whereas laparoscopic and robotic surgeries had increased to 31.1% and 23.2%, respectively, resulting in a total MIS rate of 54.3% (including 3.3% conversion to open surgery) [3,16]. Some centers now perform MIS in most pediatric CC cases, and this trend is expected to continue as laparoscopic and robotic technologies improve [6].
1. Laparoscopic CC surgery
Laparoscopic surgery for CC is becoming increasingly popular worldwide. Compared with conventional laparotomy, laparoscopic CC operations have been reported to differ in operative time, hospital length of stay (LOS), time for recovery of bowel function, intraoperative transfusion, bile leakage, abdominal bleeding, anastomotic stenosis, pancreatitis, adhesive small bowel obstruction, and total complications. Although a relatively longer operative time is considered a critical weakness of laparoscopic surgery, it is associated with shorter LOS and faster bowel movement recovery. Anastomotic stenosis, bile leak, and Roux limb obstruction occur more frequently during open surgery [10,17]. Additionally, laparoscopic surgery generally requires fewer transfusions and results in a lower incidence of postoperative intestinal obstruction [9,10].
In Korea, with an increase in experience, based on newly acquired data, only a few institutions have reported the results of laparoscopic CC surgery. Reports from the early 2010s have focused on initial experiences [18,19], whereas recent studies have reported long-term outcomes [20]. These results are consistent with international findings, confirming that laparoscopic CC surgery is a safe and cosmetically favorable alternative standard method despite being associated with longer operation times. The average operation time varied from 181.3 to 319.4 minutes [14,18,19,21,22]. Biliary leakage, subhepatic fluid collection, and pancreatic fistulas are some of the few encountered complications [23]. Postoperative complications, including ileus, wound infection, subhepatic fluid collection, pancreatitis [20], bile leakage, afferent loop syndrome, and cholangitis [3], are rare.
A learning curve for laparoscopic CC surgery has been noted, with initial longer operative times that decrease as the surgeon’s proficiency improves [18,19]. Hepaticoduodenostomy, sometimes used in other countries to shorten the surgery time, is rarely performed in Korea [3].
Studies on single-incision laparoscopic surgery (SILS) for pediatric CC have been actively conducted. In terms of operative time, bleeding, LOS, bowel function recovery, and immediate- and long-term outcomes, SILS generally shows no significant differences from conventional laparoscopy. However, SILS offers advantages in terms of aesthetic outcomes, resulting in higher patient and parent satisfaction [10,24-26]. In Korea, only two conference papers reported SILS for pediatric CC, involving 18 cases [27,28]. The results were generally positive, with one patient requiring open conversion and three needing additional port insertions. The average operative time was 300 minutes, similar to that of previously reported conventional laparoscopic surgeries. The incision length was significantly shorter in the SILS group, and no mortality or morbidity was reported [27,28]. Therefore, SILS appears to be a feasible surgical option for pediatric patients with CC.
2. Current status of robotic surgery for CC
Robotic surgery offers enhanced three-dimensional visualization and greater manipulation flexibility, making it easier to perform intricate procedures such as hepaticojejunostomy than laparoscopic surgery [15]. Surgical outcomes, including operative time and short- and long-term complications, are reportedly similar to those of laparoscopic surgery [29]. However, there are some issues with robotic CC surgery, including longer operation times [30] and higher initial complication rates 15 than those with laparoscopic or open surgery. These challenges can be overcome by increasing the experience of the operator and surgical team [31,32]. Additionally, the size of the robotic equipment makes it difficult to use in neonates [15]. The cost of robotic surgery is significantly higher than that of laparoscopic or open surgeries. Although no studies have been conducted on the cost to pediatric patients in Korea, a study on adults in the country revealed that because robotic surgery is not covered by insurance and is not reimbursed by the National Health Insurance Service, the patients’ financial burden is significantly higher in the robotic surgery group [33].
According to recent reports from Korea, the average operation time ranges from 348 to 493 minutes, with console times between 236 and 288 minutes [4,29,30,32,34]. Complications such as postoperative bile leakage, hepaticojejunostomy site stricture, afferent loop obstruction, and late-onset pancreatitis have been documented. Some reports have indicated that complication rates are significantly lower with robotic surgery than with laparoscopic surgery [30].
In 2024, Jung [35] successfully performed the first single-incision robotic surgery on pediatric patients in Korea. This advancement overcomes the limitations of traditional robotic surgery, such as large port size, and suggests promising future developments.
Given these advantages, the use of robotic surgery for CC is expected to increase. However, unless further advancements in instrumentation are made, broader applications remain limited.
CASES OF PRENATAL DIAGNOSIS AND NEONATAL CASES
With the widespread use of prenatal ultrasonography, the diagnosis of CC before birth has increased. The fact that the timing of surgery in prenatally diagnosed cases may influence the prognosis makes this an important area of research. Ho et al. [36] conducted a study on 35 cases of prenatally diagnosed CC and divided them into early and delayed surgery groups based on a cutoff age of 30 days. Among patients with no symptoms related to CC, the delayed surgery group showed better outcomes [36]. A comparative study of laparoscopic and open surgery on 43 neonates found that although laparoscopic surgery presented certain challenges, laparoscopic CC excision was safe and feasible with acceptable outcomes when performed with careful monitoring [37].
LIMITATION
This study includes content from conference presentations. Unlike peer-reviewed publications, conference papers have not undergone formal peer review; therefore, the data should be interpreted with caution owing to inherent limitations.
CONCLUSION
Laparoscopic and robotic surgeries appear to have favorable short- and long-term outcomes, including results beyond 10 years. Compared with the past, the use of MIS has continued to increase. Although robotic surgery offers significant advantages in terms of the ease of anastomosis and other factors, it is likely to be preferred in the future. However, challenges, such as relatively high cost, longer operation time, and difficulty adapting to small patients, such as neonates, have not yet been fully overcome. Currently, laparoscopic surgery remains the standard procedure. However, if advancements in robotic technology overcome these limitations, robotic surgery will become another standard procedure, even for small patients.
To date, only a few institutions have reported their results. However, if results from more institutions and multi-institutional studies are published, the understanding of MIS outcomes for CC could be improved. Therefore, further studies are warranted.
Notes
CONFLICT OF INTEREST
The authors report no conflict of interest.
FUNDING
This study was supported by a 2024 research grant from Pusan National University Yangsan Hospital.