Feasibility and safety of transumbilical single-incision laparoendoscopic surgery for giant choledochal cysts in infants: a single-center retrospective study

Abstract

Background

Radical resection of giant choledochal cysts (diameter ≥ 10 cm) in infants presents technical challenges, particularly when attempted with minimally invasive approaches. The primary difficulty lies in the cyst’s mass effect in the limited abdominal space. Although transumbilical laparoendoscopic single-site surgery (LESS) offers potential cosmetic and minimally invasive advantages, evidence regarding its feasibility and safety for managing these giant cysts remains limited.

Methods

This single-center, retrospective study with a historical control group included infants who underwent radical excision for giant choledochal cysts between June 2016 and December 2024. The final follow-up date for the full cohort was September 30, 2025. All patients were assigned to either the LESS group (n = 9) or the open surgery cohort (n = 18), which served as the historical control. During transumbilical LESS, we relied on cyst decompression and a novel “relay suspension technique”. This combination effectively facilitated intraoperative exposure. Perioperative and follow-up outcomes were compared between the two groups.

Results

The two groups were comparable in baseline characteristics. Operative time was longer in the LESS group (median 3.4 h vs. 2.5 h; p = 0.006). However, patients benefited from reduced intraoperative blood loss (median 10.0 ml vs. 20.0 ml; p < 0.001), shorter postoperative fasting time (median 2.0 days vs. 3.0 days; p = 0.011), and shorter duration of abdominal drainage (median 0.0 days vs. 4.0 days; p = 0.001). The two groups demonstrated comparable postoperative hospital stays and complication rates. All LESS procedures were completed without conversion to open surgery. At a median follow-up of 33 months, no late complications occurred in the LESS group, and cosmetic outcomes were favorable.

Conclusions

In this preliminary single-center retrospective study, the transumbilical LESS approach was supplemented by cyst decompression and a “relay suspension technique.” For specific infants with giant choledochal cysts, this approach appears to be a feasible and safe minimally invasive option. But this conclusion is based on procedures performed by experienced teams at specialized centers. This approach offers potential advantages in blood loss and early recovery. At a median follow-up of 33 months, cosmetic and long-term outcomes are favorable. While these findings are encouraging, they should be considered preliminary pending validation in larger, prospective studies.

Introduction

Choledochal cysts, a form of congenital biliary dilatations, are encountered primarily in the pediatric population with a female-to-male ratio of 4:1. The standard curative procedure currently is complete cyst excision with Roux-en-Y hepaticojejunostomy [1].

Although traditional open surgery achieves definitive cure, it imposes substantial trauma, necessitates prolonged recovery, and results in a prominent abdominal scar. With advances in minimally invasive techniques, multi-port laparoscopic surgery has emerged as a key treatment modality due to its cosmetic benefits and reduced postoperative pain [2, 3]. However, the application of this technique in infants, especially those with giant cysts (diameter ≥ 10 cm), presents several formidable challenges. The giant cyst disproportionately compromises the already limited abdominal space in these infants, causing significant instrument crowding and a restricted field of view. As a result, the critical step of hepaticojejunostomy is technically more challenging [4,5].

Laparoendoscopic single-site surgery (LESS) has emerged as a logical progression in minimally invasive surgery, offering the potential to further reduce surgical trauma and improve cosmetic outcomes. Although confining all trocars within a single umbilical incision allows LESS to achieve a virtually scarless outcome, its application to the radical resection of choledochal cysts in infants proves extremely difficult. This approach has inherent limitations, including loss of instrument triangulation, significant instrument crowding, and impaired depth perception. These issues are further compounded by the coaxial alignment of instruments and the camera. Consequently, performing a precise hepaticojejunostomy under such conditions becomes exceedingly difficult. This limits its widespread adoption [6,7].

Although previous studies have investigated LESS for choledochal cysts in broader pediatric populations [8, 9], high-quality evidence specifically addressing its safety and applicability for giant cysts in infants remains limited. Technical solutions to overcome the extreme space limitation in this unique subgroup are underexplored. Therefore, this study was designed to evaluate the feasibility and safety of transumbilical LESS for giant choledochal cysts in infants. The primary aim was to report our initial experience with this procedure in this specific population, to evaluate the associated technical strategies, perioperative outcomes, and preliminary long-term follow-up results. Given the exploratory nature of this single-center experience with a modest sample size, this study is intended to be hypothesis-generating, offering preliminary evidence to guide and power future prospective investigations.

Materials and methods

Study design and patient selection

This single-center, retrospective, historical control study was approved by the Ethics Committee of the Children’s Hospital of Chongqing Medical University (Approval No. 2025 − 493; Date of Approval: December 2, 2025) and was conducted in accordance with the ethical principles of the Declaration of Helsinki. Informed consent was obtained from the parents or legal guardians of all participants.

Clinical data from patients with choledochal cysts who underwent radical surgery at our hospital from June 2016 to December 2024 were retrospectively analyzed. Inclusion criteria were: (a) age < 1 year; (b) a Type I choledochal cyst diagnosed by ultrasound and magnetic resonance cholangiopancreatography (MRCP); and (c) a maximum cyst diameter ≥ 10 cm, measured on preoperative axial MRCP images using standardized electronic calipers on a Picture Archiving and Communication System (PACS) workstation. Exclusion criteria included previous upper abdominal surgery or the presence of other severe malformations requiring simultaneous correction or emergency surgery.

A total of 27 patients were enrolled. The median age at surgery was 145 days (IQR: 64–214 days; range, 17 to 342 days). Patients were divided into two groups according to the surgical approach and the period of its adoption:

• Open surgery group (n = 18): This historical cohort comprised two subsets: (1) a consecutive series of 17 patients who underwent open surgery between June 2016 and June 2020, during which period open surgery was the institutional standard of care; and (2) one patient whose parents opted for open surgery after July 2020 following an informed consent discussion.

• LESS group (n = 9): This cohort comprised all patients who underwent LESS between July 2020 and December 2024. Beginning in July 2020, the LESS procedure was introduced as the first-line approach for giant choledochal cysts. Parents of all eligible infants admitted thereafter were thoroughly counseled on the potential advantages and disadvantages of both the open and LESS approaches. The LESS procedure was performed unless parents explicitly refused it in favor of open surgery following this consultation. Only one family declined LESS during this period .

Surgical techniques

Surgical team and preclinical training

All procedures were performed by the same senior pediatric hepatobiliary surgical team. Prior to July 2020, the team had extensive experience in multi-port laparoscopic hepatobiliary surgery for older children, including hepaticojejunostomy for choledochal cysts, and was proficient in advanced laparoscopic suturing. However, conventional multi-port laparoscopy was not routinely offered to infants with giant cysts due to concerns over the severely limited working space.

To facilitate the transition to transumbilical LESS in July 2020, the team completed structured preclinical training, which included simulation exercises and animal model practice. Training focused on single-port instrument manipulation and the development of the “relay suspension technique” to overcome the challenges of coaxial vision and lost triangulation.

KEY steps of the LESS procedure

Patient positioning and surgical team setup

The infant was placed in the supine position, with legs abducted in a modified lithotomy posture and the head elevated approximately 15–20°in reverse Trendelenburg. The primary surgeon and the camera assistant (first assistant) stood between the legs of the infant, while the second assistant stood on the right side.

Surgical incision and access

A vertical incision was made at the umbilical fold, approximately 1.5–2.0 cm in length. The skin and subcutaneous tissue were incised, and the abdomen was penetrated layer by layer. Three trocars were inserted in parallel: typically two 3-mm trocars and one 5-mm trocar (for the laparoscope). All instruments were inserted through this single incision, keeping them in the same plane to minimize interference (Fig. 1).

Fig. 1.

Transumbilical single-incision Laparoendoscopic port configuration and external suture retraction. Illustration of the surgical setup in a female infant with a giant choledochal cyst. Three trocars (two 3-mm and one 5-mm) are placed in parallel through a single vertical umbilical incision. Additionally, three transcutaneous sutures are shown, which are passed through the abdominal wall to retract the gallbladder and cyst wall, providing critical exposure and creating an operative triangle

Pneumoperitoneum and space establishment

The pneumoperitoneum pressure was maintained at 8 mm Hg. After entering the abdominal cavity, the anterior wall of the cyst was incised using an electrocautery hook, and the bile or infectious fluid was thoroughly evacuated with suction (Fig. 2a). Cyst collapse significantly expanded the intra-abdominal working space.

Fig. 2.

a. Cyst decompression by suction evacuation. Intraoperative view showing initial decompression of the giant choledochal cyst using a suction device. Aspiration of the bile contents dramatically reduces the cyst volume, creating a workable surgical space within the infant's limited abdominal cavity and minimizing the risk of inadvertent injury during subsequent dissection. b. The "Relay Suspension Technique" for enhanced exposure.Schematic depicting the key maneuver of the relay suspension technique. Transabdominal sutures have been placed at the gallbladder fundus and the proximal cyst wall (near the hepatic duct). These sutures are externalized and held under tension by an assistant, effectively lifting the structures away from the posterior plane and providing dynamic, three-dimensional exposure of the critical anatomy behind the cyst. c. Dynamic traction for posterior plane visualization. Intraoperative view demonstrating the effect of dynamic traction on both the proximal and distal cyst walls. The suspension sutures allow for clear visualization of the posterior plane between the cyst and the underlying critical structures, such as the portal vein and hepatic artery, facilitating safe and precise dissection.

“Relay suspension technique” (key steps)

To achieve optimal exposure, we employed the ‘relay suspension technique’ using 3 − 0 needle sutures. Key puncture and suture sites included the seromuscular layer of the gallbladder fundus, the proximal cyst wall (hepatic duct side), and the distal cyst wall (duodenal side) (Fig. 2b and c). These sutures were exteriorized through the abdominal wall. An assistant then provided traction, continually adjusting the tension and direction of each suspension line according to the procedural progress, functioning like a “relay”. This technique provided three-dimensional, clear exposure of the anatomical plane between the cyst and the posterior structures (portal vein, hepatic artery, and duodenum), thereby effectively preventing iatrogenic injury.

Cyst resection and anastomosis

Under the excellent exposure provided by the suspension sutures, the cystic artery was ligated at the base of the gallbladder neck. The gallbladder was dissected subserosally, while the suspension suture traversing the abdominal wall and the serosal layer of the gallbladder fundus was preserved. The cyst was meticulously dissected close to its wall. The distal end of the cyst was transected proximal to the pancreaticobiliary junction. The protein plugs in the common duct were removed by inserting an 8-Fr urinary catheter through a 3-mm trocar and gently irrigating with normal saline.

• ✔ Distal cyst stump: In cases of distal stenosis, the stump was left unligated; in non-stenotic cases, it was ligated to prevent pancreatic leakage.

•  ✔ Proximal cyst: The cyst was dissected to the hepatic hilum and divided along its superior border. The intrahepatic bile duct was explored with a laparoscopic lens. If concomitant hepatic duct stenosis was identified, hepatic duct plasty was performed, by longitudinally incising the anterior wall of the hepatic duct and transversely anastomosing it to the Roux-en-Y biliary limb.

• ✔ Cyst removal: The cyst was completely dissected and removed.

• ✔ Jejunal transection and Roux limb preparation: The jejunum was transected approximately 15 cm distal to the ligament of Treitz at a site with a wide avascular space within the same vascular arcade. The corresponding mesentery and vascular arcade were divided. The jejunum was exteriorized through the umbilical incision. The blind end of the bile limb was routinely closed.

• ✔ Hepaticojejunostomy: The Roux-en-Y biliary limb was brought to the hepatic hilum via the retrocolic route. End-to-side hepaticojejunostomy was performed with 6 − 0 PDS sutures.

Wound closure

Following completion of the intracorporeal procedure, the primary umbilical fascial defect was closed under direct vision with interrupted 3 − 0 absorbable monofilament sutures to minimize the risk of postoperative hernia. When surgical drainage was indicated, an 8-Fr silicone tube was placed into the abdomen through one of the existing 3-mm trocar sleeves and exteriorized through the umbilical skin incision prior to fascial closure. Consequently, upon drain removal, only a minimal cutaneous tract (< 5 mm) remained, which was managed expectantly to heal by secondary intention—a standard approach for such small-caliber sites. The skin was finally approximated with a subcuticular absorbable suture, rendering the incision virtually invisible within the umbilicus.

Open surgery group

An oblique incision was made below the right costal margin, approximately 5 to 8 cm in length. After layered entry into the abdominal cavity, cyst resection and Roux-en-Y hepaticojejunostomy were performed using conventional surgical instruments and techniques. The core steps of the operation were consistent with those of the laparoscopic group.

Postoperative management

All perioperative management, including the guidelines for feeding initiation and drain care, was conducted within the framework of the institutional Enhanced Recovery After Surgery (ERAS) protocol, which remained consistent throughout the study period.

Data collection and outcome definitions

Perioperative and follow-up data were systematically extracted from electronic medical records. Key study variables were defined as follows:

Key recovery outcomes

• Postoperative fasting time was defined as the interval from the end of surgery to the first tolerated oral intake of clear liquids, age-appropriate milk, or formula that was not followed by vomiting or abdominal distension requiring cessation of feeding.

• Duration of abdominal drainage was recorded for all patients. For those in whom no drain was placed based on intraoperative assessment of a dry anastomosis, the duration was recorded as 0 days. When placed, a single 8Fr silicone drain was positioned near the hepaticojejunostomy via the operative incision (umbilical for LESS, subcostal for open surgery). Drains were removed according to standardized criteria: output < 1 ml/kg/day and non-bilious appearance.

Complication assessment and definitions

Postoperative complications were graded according to the Clavien-Dindo classification. Specific definitions for long-term complications monitored during follow-up were:

• Anastomotic stricture: Clinical jaundice or recurrent cholangitis with radiologic confirmation (MRCP or PTC).

• Cholangitis: Episodes of fever (> 38.5 °C), jaundice, and abdominal pain with supportive laboratory findings.

• Pancreatitis: Abdominal pain with vomiting and serum amylase or lipase > 3 times the upper limit of normal.

• Biliary stone formation: Identified by ultrasonography or MRCP.

Follow-up

All patients were followed up at 1, 3, and 6 months postoperatively, and annually thereafter. Each visit included clinical assessment, blood tests (liver function tests and complete blood count), and abdominal ultrasonography. MRCP was performed only for suspected biliary complications. The data cutoff for the present analysis was September 30, 2025. No patient was lost to follow-up.

Statistical analysis

SPSS version 26.0 was used for statistical analysis. Continuous variables with a normal distribution are presented as mean ± standard deviation and were compared using the independent samples t-test. Non-normally distributed data are reported as median (interquartile range) and were analyzed with the Mann–Whitney U test. Categorical variables are expressed as number (%) and were compared with Fisher’s exact test. Effect sizes for group differences are reported as mean difference (MD) or median difference with 95% confidence intervals (CI) for continuous variables, and as odds ratio (OR) with 95% CI for categorical variables. A P-value < 0.05 was considered statistically significant. The learning curve for the LESS procedure was evaluated by cumulative sum (CUSUM) analysis of operative time.

Results

Baseline characteristics

No significant differences were observed between the two groups in gender, operative age, maximum cyst diameter, clinical presentations, prenatal diagnosis rate, proportion of intrahepatic bile duct dilatation, preoperative liver function (ALT, AST, direct bilirubin, GGT), or preoperative white blood cell count (all p > 0.05, Table 1). While effect size estimates suggested no substantial between-group differences, the wide confidence intervals reflect the modest sample size.

Table 1.

Baseline characteristics in the LESS and open surgery groups

Indicators	LESS group (n = 9)	Open surgery group (n = 18)	P-value	Effect Size (95% CI)1
Demographics
Male, n (%)	2 (22.2)	3 (16.7)	1.000	OR = 1.43 (0.19 to 10.53)
Age at surgery (days), Mean ± SD	157.1 ± 91.3	137.5 ± 89.8	0.599	MD = 19.6 (-56.3 to 95.5)
Cyst Characteristics
Maximum cyst diameter (cm), median (IQR)	10.0 (10.0 to 11.0)	10.0 (10.0 to 12.5)	0.561	median difference = 0.0 (-1.0 to 0.0)
Clinical Presentation & Comorbidities
Jaundice, n (%)	6 (66.7)	14 (77.8)	0.653	OR = 0.57 (0.10 to 3.38)
Acholic stools, n (%)	3 (33.3)	8 (44.4)	0.692	OR = 0.63 (0.12 to 3.31)
Palpable abdominal mass, n (%)	4 (44.4)	10 (55.6)	0.695	OR = 0.64 (0.13 to 3.21)
Prenatal diagnosis, n (%)	3 (33.3)	9 (50.0)	0.683	OR = 0.50 (0.09 to 2.65)
Combined intrahepatic bile duct dilatation, n (%)	7 (77.8)	13(72.2)	1.000	OR = 1.35 (0.2 to 8.9)
ALT (U/L), median (IQR)	44.0 (16.5 to 211.0)	120.6 (31.0 to 196.9)	0.504	median difference= -17.9 (-116.3 to 112.4)
AST (U/L), median (IQR)	149.0 (37.0 to 258.0)	171.6 (53.0 to 384.1)	0.440	median difference = -27.9 (-180.8 to 86.6)
Direct bilirubin (µmol/L), median (IQR)	45.2 (20.6 to 145.3)	72.8 (28.6 to 111.0)	0.797	median difference = 6.0 (-52.6 to 68.1)
GGT (U/L), median (IQR)	470.5 (269.5 to 1505.0)	1202.6 (457.0 to 2675.7)	0.222	median difference  = -650.9 (-1781.0 to 147.0)
Preoperative Laboratory
White blood cells (×10⁹/L) Mean ± SD	14.2 ± 3.8	13.3 ± 4.6	0.590	MD = 1.0 (-2.7 to 4.6)

Abbreviations: LESS Laparoscopic Single-site Surgery, IQR Interquartile Range, ALT Alanine Aminotransferase, AST Aspartate Aminotransferase, GGT Gamma-Glutamyl Transferase, OR Odds ratio, MD Mean difference, CI Confidence interval

1 Effect size is presented as the odds ratio (OR) for categorical variables, mean difference (MD) for normally distributed continuous variables, or median difference for non-normally distributed continuous variables. Categorical variables were compared using Fisher’s exact test. Continuous variables were compared using the independent samples *t*-test (normally distributed) or the Mann-Whitney U test (non-normally distributed), as appropriate

Perioperative Outcomes

Perioperative outcomes are summarized in Table 2. As anticipated, operative time was significantly longer in the LESS group than in the open surgery group (median 3.4 h vs. 2.5 h; median difference 1.1 h, 95% CI 0.5 to 1.9; p = 0.006). A pronounced learning curve was evident for the LESS procedure (Fig. 3). CUSUM analysis of operative time identified two distinct phases: Case 1 represented the learning curve, and Cases 2–9 marked the proficiency phase. The operative time for the first case was 6.5 h; the subsequent eight cases were all completed within 4.5 h, with a trend of decreasing duration (final case: 2.8 h). Detailed operative times for each consecutive case are provided in Table 3.

Table 2.

Perioperative outcomes in the LESS and open surgery groups

Indicators	LESS group (n = 9)	Open surgery group (n = 18)	P-value	Effect Size (95% CI)1
Intraoperative indicators
operative time (h), median (IQR)	3.4 (3.2 to 4.4)	2.5 (2.0 to 3.4)	0.006	median difference = 1.1(0.5 to 1.9)
Intraoperative blood loss (ml), median (IQR)	10.0 (5.0 to 15.0)	20.0 (20.0 to 50.0)	< 0.001	median difference =-15.0 (-40.0 to -5.0)
Intraoperative blood transfusion, n (%)	2 (22.2)	7 (38.9)	0.667	OR = 0.45 (0.07 to 2.82)
Postoperative outcomes
Duration of drainage (days) 2, median (IQR)	0.0 (0.0 to 3.3)	4.0 (4.0 to 6.0)	0.001	median difference =-4.0 (-6.0 to -3.0)
Postoperative fasting time (days), median (IQR)	2 0.0 (2.0 to 3.0)	3.0 (3.0 to 3.0)	0.011	Median difference . =-1.0 (-1.0 to 0.0)
Postoperative hospital stay (days), median (IQR)	8.0 (8.0 to 11.0)	8.5 (8.0 to 10.0)	0.649	median difference = 0.0 (-1.0 to 2.0)
Postoperative complications, n (%)3	0 (0)	1 (5.6)	1.000	-

1. Effect size is presented as the median difference for non-normally distributed continuous variables or the odds ratio (OR) for categorical variables. Continuous variables were compared using the Mann-Whitney U test; categorical variables were compared using Fisher’s exact test

2. Patients without a surgical drain were assigned a value of 0.0 days

3. Complications in the open group were a chyle leak (Clavien-Dindo grade I). The odds ratio is not calculable (zero events in the LESS group)

4. Values in bold are statistically significant (p < 0.05)

Fig. 3.

CUSUM analysis of operative time for the nine consecutive LESS cases. CUSUM analysis of operative time identified two distinct phases: an initial learning phase (the first case) and a subsequent proficiency phase (cases 2-9)

Table 3.

Operative times for consecutive cases in the LESS group

Case Sequence Number	Operative Time (h)
1	6.5
2	3.2
3	3.2
4	4.3
5	3.4
6	3.6
7	4.4
8	3.4
9	2.8

Intraoperative blood loss was lower in the LESS group (median 10.0 ml vs. 20.0 ml; median difference -15.0 ml, 95% CI -40.0 to -5.0; p < 0.001). Although the blood transfusion rate was lower in the LESS group (22.2% vs. 38.9%), the difference was not statistically significant (OR 0.45, 95% CI 0.07 to 2.82; p = 0.667).

Postoperative fasting time appeared to be shorter in the LESS group than in the open surgery group (median 2.0 days vs. 3.0 days; median difference -1.0 day, 95% CI -1.0 to 0.0; p = 0.011). The duration of abdominal drainage was also markedly shorter in the LESS group (median 0.0 days vs. 4.0 days; median difference -4.0 days, 95% CI -6.0 to -3.0; p = 0.001). Notably, 6 patients (66.7%) in the LESS group did not require a surgical drain based on intraoperative assessment of a dry anastomosis and minimal dissection bed oozing; these patients were assigned a value of 0 days. The median postoperative hospital stay did not differ significantly between the two groups (median 8.0 days for LESS vs. 8.5 days for open surgery; median difference 0.0 days, 95% CI -1.0 to 2.0; p = 0.649).

Regarding complications, one patient in the open group developed a chyle leak on postoperative day 4, which was classified as Grade I according to the Clavien-Dindo system. This resolved conservatively with a low-fat diet by day 11. No major complications (e.g., anastomotic leakage, stricture, or pancreatic leakage) occurred in the LESS group. No patient in either cohort required invasive reintervention or readmission related to the index surgery. The overall complication rate was not significantly different (p = 1.000). Critically, no conversions to open surgery were required in the LESS group.

Follow-up outcomes

At a median follow-up of 80 months (IQR: 74–95) for the open surgery group and 33 months (IQR: 14–38.5) for the LESS group, all patients included in the analysis had a minimum follow-up of 9 months. Importantly, no long-term complications, such as anastomotic stricture, cholangitis, pancreatic complications, or cyst recurrence, were observed in either group during this period. Furthermore, no umbilical or incisional hernias developed throughout follow-up, and no reinterventions were required. Notably, no appreciable scar was detected in the LESS group throughout follow-up (Fig. 4).

Discussion

Early diagnosis and timely radical surgical intervention for choledochal cysts are essential to prevent the development of secondary biliary cirrhosis and malignant transformation [10,11]. However, radical surgery of giant choledochal cysts (diameter ≥ 10 cm) in infants remains a significant challenge in pediatric surgery. These infants have a small abdominal volume with a significant space-occupying effect. They often present with severe liver dysfunction, cholestasis, and even liver cirrhosis. The technical difficulty and surgical risk rise sharply in infants as compared with older children or those with smaller cysts [12,13]. We compared perioperative parameters and the recovery outcomes between transumbilical LESS and open surgery in infants with giant choledochal cysts. The findings provide preliminary evidence that LESS is feasible, safe, and offers minimally invasive benefits. These advantages may support its wider adoption in clinical practice.

Surgical challenges of giant choledochal cyst in infants and the learning curve

The operative field in infants is severely constrained by the small abdominal cavity. Furthermore, giant choledochal cysts are often found to envelop and compress the portal vein, hepatic artery and duodenum. This compression distorts normal tissue planes and heightens the risk of massive hemorrhage or inadvertent injury during surgery [14]. These infants often have comorbidities, including intrahepatic bile duct dilatation, biliary cirrhosis or congenital heart disease. Their tolerance to anesthesia and surgery is often poor.

Hepaticojejunostomy is the most critical and technically demanding step in the procedure, requiring a precise anastomosis under surgical loupes or microscope. Anastomotic complications, especially stricture or bile leakage, remain the main reasons for reoperation and unfavorable outcomes [15]. Multi-port laparoscopy, while minimally invasive, often leads to instrument crowding and a limited visual field in infants [16]. Transumbilical LESS further improves cosmesis, but it poses greater technical challenges. The main challenges are the loss of instrument triangulation and the coaxial alignment of instruments with the camera.

Because of these factors and the confined operative space in infants with giant cysts, the transumbilical LESS approach has a steep learning curve [17,18]. Our CUSUM analysis (Fig. 3) demonstrates that a distinct proficiency phase was achieved after the first case. From the second case onward, operative times consistently fell below 4.5 h. This rapid improvement resulted from case accumulation and proactive preparatory measures, including specialized simulation training and preoperative team briefings that optimized coordination and instrument handling. These findings suggest that targeted training and accumulated experience can offset the initial time disadvantage of LESS. With increasing team proficiency, operative times for LESS will approach those of open surgery, while maintaining its minimally invasive benefits.

The absence of conversions and major complications in the LESS group demonstrate that these technical challenges can be managed by experienced surgeons. The absence of port-site complications further supports this procedural safety; specifically, no umbilical hernias were observed during follow-up. This outcome supports our practice of meticulous fascial closure.

Drawing from this experience, we can provide more specific guidance on case selection. The feasibility of the transumbilical LESS approach is not determined solely by a strict cyst diameter cutoff, but rather by a combination of anatomical and pathological factors. Although successfully applied to cysts ≥ 10 cm in this series, the principal technical impediments stem more from the cyst’s spatial relationship to the porta hepatis and retroperitoneal structures than from its absolute size. Factors that increase procedural difficulty include: (1) deep extension of the cyst into the hepatic hilum with intimate adherence to the portal vein and hepatic artery; (2) severe pericystic inflammation or prior infection that obscures dissection planes; and (3) significant intrahepatic ductal dilatation necessitating complex hepaticojejunostomy. Therefore, meticulous review of preoperative imaging to assess these nuances is paramount. We recommend that initial LESS attempts for giant cysts be reserved for cases with relatively favorable anatomy, progressing to more complex scenarios as surgical proficiency increases. Safety must remain the overriding principle, with a low threshold for conversion to open surgery if the critical view and safe dissection cannot be reliably achieved via the single-incision approach.

Technical strategies for addressing challenges in transumbilical LESS

To overcome these spatial and technical hurdles, we introduced and standardized two important manoeuvres. The simple but critical first step was initial cyst decompression to establish a workable surgery environment. More notably, the key innovation was the “relay suspension technique” to dynamically recreate a three-dimensional operative field. Three-dimensional and dynamic exposure of the structure of the hepatic portal area was attained by directional suture and external traction at various critical points, including the gallbladder fundus and proximal/distal ends of the cyst, and dynamic correction of the traction direction. This is a reliable method of preventing injury to the portal vein and the hepatic artery, thus providing the environment to achieve a precise anastomosis. The technique can simulate the assistant’s traction effect in open surgery or multi-port laparoscopic surgery to some degree, addressing the lack of triangulation in LESS, and substantially improving its controllability and safety of LESS [19,20]. The successful implementation of LESS for the radical resection of giant choledochal cysts in infants hinges on the systematic optimization of these technical factors. Moreover, the strategies mentioned here can be insightful in the application of the LESS approach to other complex processes in closed anatomical spaces. The regularity of our results, no open surgery conversions and no significant complications, indicates that this method is not an anecdotal workaround, but a reproducible and dependable methodology that has greatly increased the controllability and safety of single-incision surgery. In our initial experience, transumbilical LESS seemed safe and feasible for specific infants with giant choledochal cysts when done by experienced teams in specialized centers. But we need larger, multicenter studies to validate whether this technique can be reproduced outside the study setting. This approach may warrant further exploration for the use of LESS in small-cavity surgery. especially in children.

Clinical benefits of transumbilical LESS

In this cohort, the LESS procedure was associated with reduced intraoperative blood loss and a shorter duration of postoperative drainage, despite a longer operative time. These findings suggest possible benefits in tissue protection and enhanced local recovery, although confounding factors cannot be entirely excluded. Similar observations have been reported in adults or older children undergoing LESS. [21,22] However, their demonstration in infants is particularly significant. With the widespread adoption and refinement of surgical techniques, including more precise anatomical dissection and the application of advanced coagulation devices, the advantages of laparoscopic surgery in minimizing intraoperative blood loss are likely to become even more pronounced [20,23]. Although no statistically significant difference in intraoperative blood transfusion rate was observed between the two groups, a trend towards reduction was noted in the LESS group (22.2%) compared with the open surgery group (38.9%). This numerical difference may carry meaningful clinical relevance. Intraoperative blood transfusion is associated with potential infectious risks, immunomodulatory effects and increased healthcare costs [24]. Accordingly, minimizing transfusion exposure remains an important perioperative objective, and the LESS approach may confer advantages in this regard.

Postoperative fasting time was significantly shorter in the LESS group than in the open surgery group. This difference may be attributed to an attenuated systemic inflammatory response and reduced stress hormone levels, including cortisol and catecholamines, associated with laparoscopic surgery compared with open surgery. This attenuated systemic stress state facilitates the recovery of physiological functions, including earlier restoration of gastrointestinal function [25,26]. These findings are consistent with the principles of ERAS, and suggest that LESS may contribute to overall recovery by enabling earlier oral nutrition. This helps preserve intestinal mucosal barrier function, limit bacterial translocation, and improve postoperative nutritional status, which may offer some benefit to the overall healing [27]. The results of this study demonstrated no significant difference in the postoperative hospital stay between the two groups. This could be explained by the fact that the consistent application of an ERAS protocol to all children undergoing major abdominal surgery at our institution. All patients followed standardized criteria for extubation, enteral feeding, and discharge, which may have masked any potential advantage of LESS in shortening hospital stay.

Of note, our investigation directly compared LESS with open surgery rather than standard multi-port laparoscopic procedures. The benefits observed in our study—reduced intraoperative blood loss and shorter postoperative fasting time—may represent general advantages of minimally invasive surgery rather than features unique to the LESS technique. Whether LESS confers additional benefits beyond those achievable with multi-port laparoscopy remains to be determined in future comparative studies.

Notably, none of the LESS procedures were converted to open surgery, and no perioperative complications such as anastomotic leakage, pancreatic leakage or strictures were observed. Importantly, no late complications (e.g., anastomotic stricture, cholangitis, pancreatitis, or reintervention) occurred in either group during the available follow-up. That’s reassuring, but we can’t claim LESS is equivalent to open surgery based on this, especially since follow-up wasn’t balanced and our sample was small.

In addition to these perioperative metrics, our follow-up data, despite the disparity between groups, are encouraging. With a median follow-up of 33 months for the LESS group and 80 months for the open group, no late complications or reinterventions occurred in either cohort, and no reinterventions were required. Notably, these findings are consistent with previous reports suggesting comparable long-term safety and functional outcomes between laparoscopic and open cyst excision within the reported follow-up periods [28]. Nevertheless, further long-term follow-up is warranted to confirm the durability of these outcomes.

The enhanced cosmetic outcome of LESS deserves consideration for its potential long-term psychosocial implications [29], a consideration often underappreciated in infant surgery. The conspicuous scar from a traditional open incision may serve as a lifelong physical reminder. Although conventional multi-port laparoscopy confers a well-documented cosmetic advantage over open surgery [30], the transumbilical LESS approach, by concealing the incision within the natural umbilicus, achieves a virtually scarless outcome (Fig. 4). Such potential benefits, including mitigating future body image concerns and supporting improved psychosocial integration, represent an important area for future research using validated patient-reported outcome measures (PROMs). Pending such formal evaluation, these benefits remain hypothesis-based rather than conclusively demonstrated. Beyond offering reduced invasiveness and faster recovery in select parameters, the LESS approach may theoretically offer long-term value by promoting not only physical but also psychological well-being. These potential benefits warrant further investigation in prospective studies with longer follow-up and validated quality-of-life and body-image questionnaires.

Fig. 4.

Long-term cosmetic outcome following transumbilical LESS. Postoperative appearance of the umbilicus in a patient who underwent LESS for a giant choledochal cyst. The photograph was taken at 24 months postoperatively. The incision is completely hidden within the umbilicus, resulting in no appreciable abdominal scar and a virtually scarless cosmetic outcome

Study limitations and future perspectives

Importantly, the current study was designed to assess the feasibility and safety of transumbilical LESS in a highly selected population of infants with giant choledochal cysts. Our findings therefore support the feasibility rather than definitive comparative effectiveness. This study has several limitations. First, its single-center, retrospective, and non-randomized design with a historical control introduces selection bias and unmeasured confounding factors. A key limitation relates to potential era effects, which are inherent to the historical control design. Although a consistent ERAS protocol was maintained throughout the study period, other elements of perioperative care, including anesthetic and analgesic techniques and the surgical team’s growing experience, likely evolved over the 8.5-year study period. These temporal changes represent significant residual confounders, limiting our ability to make causal conclusions about the surgical approach (LESS vs. open surgery) and the observed outcomes.

Second, the sample size, particularly for the LESS group (n = 9), is modest, which may limit the statistical power to detect rare adverse events. The absence of a multi-port laparoscopic control group limits our ability to conclude whether the observed benefits are attributable to laparoscopy in general or specific to the LESS approach.

Third, the follow-up duration was asymmetrical between the two groups due to the chronological adoption of LESS. This disparity necessitates caution in directly comparing long-term complication rates, because complications like anastomotic stricture may emerge years postoperatively.

Given these limitations, our findings should be interpreted as exploratory and hypothesis-generating, not as definitive evidence of equivalence or non-inferiority. They reflect our preliminary institutional experience and suggest that, with the aid of specific technical maneuvers, the transumbilical LESS approach is a feasible and safe option in this challenging population. These encouraging preliminary findings are tentative and need to be verified through larger and prospective multi-center studies with contemporaneous control groups to more rigorously assess comparative effectiveness and control for confounding. Additionally, all procedures were performed by the same senior surgical team, and there is a learning curve to master the technique. Regarding technical dissemination, we recommend a structured training pathway that includes simulation training, animal models, and progressive clinical implementation to shorten the learning curve for LESS, and facilitate its standardization and wider adoption [31, 32].

Conclusion

In this preliminary, single-center retrospective study, the transumbilical LESS approach, supplemented by cyst decompression and the “relay suspension technique”, appears to be a feasible and safe minimally invasive option for the resection of giant choledochal cysts in infants when performed at experienced centers. Compared to a historical open surgery cohort, this minimally invasive approach was associated with reduced intraoperative blood loss, accelerated recovery in certain parameters, and favorable cosmetic outcomes. No late complications were observed within the available follow-up period. These findings reflect our initial institutional experience and should not be interpreted as demonstrating superiority, equivalence, or generalizability beyond the study setting. They do, however, provide a rationale for further investigation and highlight the importance of specialized centers with advanced pediatric laparoscopic expertise. Larger, prospective, multicenter studies with contemporaneous control groups are warranted to validate these preliminary findings and to further establish the role of LESS in this challenging patient population.

Abbreviations

LESS

laparoendoscopic single-site surgery

ERAS

Enhanced Recovery After Surgery

Authors’ contributions

Huanli Han analyzed the data and wrote the paper. Huanli Han performed the statistical analyses. Jianyang Hu designed the study, Xiaoke Dai and Mingman Zhang evaluated the manuscript.

Funding

This study was supported by the National Clinical Key Specialty Construction Project (National Health Commission Office Medical Administration Letter〔2024〕189).

Data availability

The datasets analyzed in the study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved and supervised by the Institutional Review Board of Children’s Hospital of Chongqing Medical University (Approval No. 2025 − 493; Date of Approval: December 2, 2025) and was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki. Informed written consent was obtained from the parents or legal guardians of all infant participants.

Consent for publication

All the patient data used in this study were approved by the guardian. Informed consent was obtained from the parents or legal guardians of all infant participants.

Competing interests

The authors declare no competing interests.