Introduction

The management of extrahepatic bile duct stones has evolved from open surgical procedures to minimally invasive approaches. Laparoscopic common bile duct exploration (LCBDE) is now established as an effective alternative to endoscopic retrograde cholangiopancreatography (ERCP). Moreover, single-incision laparoscopic surgery (SILS) has gained increasing recognition in hepatobiliary surgery because of its potential advantages in terms of cosmetic outcomes and postoperative recovery1. The convergence of mature LCBDE techniques2,3,4 and advancing single-incision instrumentation has enabled the performance of SIL-CBDE5,6,7,8,9.

The selection of a single-incision laparoscopic approach, the optimization of surgical field exposure, and the application of choledochoscopy during CBDE remain challenges that surgeons urgently need to address10. In the past three years, while using SIL-CBDE via the umbilicus to treat extrahepatic bile duct stones, we have innovatively performed SIL-CBDE via a caesarean scar approach, with promising initial results.

Materials and methods

Patient selection

This study retrospectively reviewed and analysed the data of 18 patients who underwent SIL-CBDE at the Department of General Surgery of the 901 st Hospital of the Joint Logistics Support Force from March 2022 to June 2024. The inclusion criteria were as follows: (1) 8 mm ≤ common bile duct (CBD) diameter ≤ 20 mm; (2) no intrahepatic bile duct stones or bile duct stricture; (3) no biliary tract variation; (4) no history of acute severe cholangitis or severe pancreatitis within 2 months; (5) no tumour obstruction at the distal bile duct; (6) stones that could be removed by choledoscopy; and (7) an anaesthesia risk classification level of ≤ 3 according to the American Society of Anesthesiologists (ASA). The exclusion criteria were as follows: (1) body mass index (BMI) ≥ 30 kg/m²; (2) pregnancy; and (3) cirrhosis complicated by portal hypertension. All patients provided written informed consent for the surgical procedures. Comprehensive disclosure included information on all available surgical approaches, as well as explicit notification of the potential for intraoperative conversion to laparotomy or placement of supplementary ports. This study was approved by the Ethics Review Committee of the 901 st Hospital of the Joint Logistics Support Force (No. 202412004). All operations were performed by a single, dedicated surgical team, with treatment modalities determined through clinician–patient mutual decision-making.

Sample size

The sample size of this exploratory cohort (n = 18) was determined by pragmatic constraints during the 28-month recruitment period (March 2022–June 2024), reflecting the technical novelty and relatively low prevalence of cases suitable for SIL-CBDE. Post hoc power analysis indicated 80% power to detect large effect sizes (Cohen’s d > 1.2) for primary outcomes but limited sensitivity for subgroup comparisons. Future multicentre collaborations will target ≥ 50 cases to achieve 90% power for detecting 20% superiority in recovery metrics.

Surgical methods

Transumbilical approach: A 2-cm curved incision was made around the umbilicus, and a multichannel, single-incision platform (Fig. 1) was inserted. Pneumoperitoneum was established, and the pressure was maintained at 10–12 mmHg. An integrated 10-mm, 30-degree rigid laparoscope (STORZ Corporation, Germany) was inserted through the 12-mm channel. For patients with a history of abdominal surgery, adhesions were dissected, and if a residual gallbladder was present, cholecystectomy was performed. For patients without a history of abdominal surgery, part of the gallbladder wall was preserved, and traction was applied to expose Calot’s triangle (Fig. 2A), followed by cholecystectomy. The subhepatic space was exposed, and a longitudinal incision (Fig. 2B) was made on the anterior wall of the CBD. The stone was removed with a basket under the guidance of a choledochoscope (Olympus Corporation, Japan) (Fig. 2C). For larger stones (Fig. 2D) in the lower CBD, the “chopstick technique”11 can be used to push the stone into the CBD incision for easier removal. The CBD incision was then sutured (Fig. 2E), and surgical gauze and specimens were removed through the single-incision platform. If necessary, under laparoscopic guidance, an 8.5 F drainage tube (Fig. 2F) was inserted through the right anterior axillary line below the costal margin into the gallbladder fossa adjacent to the CBD. A thorough inspection of the surgical field confirmed complete haemostasis and the absence of bile leakage. After the gallbladder suspension and pneumoperitoneum were removed, the platform was removed, and the abdominal wall incision (Fig. 3) was sutured in layers.

In the caesarean scar approach, a small 2–3 cm incision (Figs. 4 and 5B) was made along the original abdominal wall scar. A fusiform resection of the scar tissue was performed. Under direct visualization, the abdomen was advanced layer by layer to the extraperitoneal fat layer, and the peritoneum was incised. The index finger was used to circumferentially explore the perimeter of the incision to assess adhesions. If adhesions, such as those of the greater omentum, were encountered, they were released under direct visualization, and the base of the operating platform (Fig. 5A) was then placed. The subsequent procedures were the same as those for the transumbilical approach.

Fig. 1
Fig. 1
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Platform placement.

Fig. 2
Fig. 2
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(A) Suspension of the reserved gallbladder wall, (B) Cold incision of the CBD, (C) Choledochoscopy, (D) Application of the “chopstick technique”11 in SIL-CBDE, (E) One-stage suture of the CBD incision, (F) An 8.5 F drainage tube is left in place.

Fig. 3
Fig. 3
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(A) Transumbilical access incision prior to suturing, (B) Closure of the transumbilical access incision.

Fig. 4
Fig. 4
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(A) Longitudinal scar approach via caesarean section, preoperative, (B) after the longitudinal scar approach via caesarean section.

Fig. 5
Fig. 5
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(A) Transcesarean section transverse scar approach, preoperative, (B) after the transcaesarean section transverse scar approach.

Efficacy indicators

Early Postoperative Pain: In the postanaesthesia care unit (PACU), incisional pain intensity was assessed 2 h postoperatively using a visual analogue scale (VAS, 0–10 cm), with 0 indicating no pain and 10 indicating the worst imaginable pain.

Cosmetic Satisfaction: Patient-reported cosmetic outcomes were assessed 6 months postoperatively using a validated 10-cm VAS, with 0 indicating very unsatisfactory scar appearance and 10 indicating a very satisfactory appearance.

Statistical analysis

All analyses were conducted using SPSS version 25.0 (IBM Corp). The normality of continuous variables was formally assessed with the Shapiro‒Wilk test. Categorical data are presented as frequencies and percentages. Continuous variables with a normal distribution are expressed as the mean ± standard deviation, whereas nonnormally distributed variables are reported as medians with interquartile ranges (IQRs).

Results

The flowchart detailing patient screening and enrolment is shown in Fig. 6. Seventeen patients successfully underwent single-incision laparoscopic one-stage suturing for CBDE utilizing the platform. However, one patient who underwent a transumbilical approach required a transition to the three-port technique because of ambiguity in the anatomical configuration of the gallbladder triangle and hepatic hilum.

Fig. 6
Fig. 6
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Patient Screening Flowchart

Table 1 lists the demographic and clinical data of the 18 patients, 14 of whom underwent a transumbilical approach and 4 who underwent a caesarean scar approach. Among the patients who underwent a transumbilical approach, 1 had extrahepatic bile duct stones after cholecystectomy, 1 had extrahepatic bile duct stones after subtotal cholecystectomy, and 12 had both cholecystolithiasis and extrahepatic bile duct stones. Among the patients who underwent a caesarean scar approach, 3 had longitudinal scars, and 1 had a transverse scar; all the patients had cholecystolithiasis and extrahepatic bile duct stones.

Table 1 Demographic and clinical data of the 18 patients.
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In this cohort, eight patients did not have prophylactic abdominal drains, while one patient developed bile leakage and abdominal pain on the first postoperative day. Postoperatively, yellow–green fluid was observed to flow out of the peritoneal cavity, and bile leakage was diagnosed. The peritoneal drain was kept in place and was patent, and the drainage volume gradually decreased within three days. Subsequent follow-up examinations did not reveal significant intra-abdominal fluid accumulation, and the patient had no abdominal pain or discomfort. The drain was removed, and the patient was considered cured and subsequently discharged. All incisions healed postoperatively with a grade A outcome, and there were no complications, such as residual stones, bile duct stenosis, or incisional hernia. As shown in Table 2, patients reported moderate pain during the early postoperative period (median VAS score: 4) and high cosmetic satisfaction 6 months after surgery (median VAS score: 7). For the two patients with postoperative follow-up durations less than six months, cosmetic satisfaction scores were assessed at their most recent follow-up visit.

Table 2 Intraoperative and postoperative conditions of 18 patients with SIL-CBDE.
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All 18 patients were followed up, and the postoperative follow-up time was 20.50 (4–31) months, during which time there were no cases of stone recurrence, readmission, or death.

Discussion

As the concept of minimally invasive surgery continues to expand, the goal of surgeons is to minimize surgical trauma and achieve the best cosmetic results. SILS effectively minimizes or hides the problem of postoperative scarring. Compared with traditional laparoscopic surgery, it has significant advantages in reducing trauma, accelerating postoperative recovery, and achieving better cosmetic results12. Manasseh et al13 reported that the key risk factors for complications of LCBDE were operator experience, patient factors, and operating techniques. Since 2015 and 2019, our team has performed SILC and LCBDE with primary suture for CBD stones. On the basis of the accumulation of previous experience, we have gradually developed SIL-CBDE technology.

The incision for traditional SIL-CBDE is mostly located at the umbilicus9,10. However, the range of umbilical incision options is limited. Therefore, in this study, we used the caesarean scar approach, and all single-incision surgeries via the caesarean scar approach were successful. Longitudinal caesarean scars were incised along the umbilicus in the original scar, and transverse caesarean scars were incised midline at the original scar. Given that the original caesarean section may cause abdominal adhesions, all the patients underwent the Hasson open abdominal approach technique14. This study revealed a patient scar satisfaction score of 7.00 (7.00, 8.00). Previous studies on SIL-CBDE have not routinely reported cosmetic satisfaction metrics. In the present case series, the outcomes for intraoperative blood loss and postoperative pain were within acceptable clinical ranges. The implementation of stricter discharge criteria, including requirements for postoperative inflammatory markers to remain within normal reference limits and no need for analgesic medication, likely contributed to an extended postoperative hospital stay.

The extent of pelvic adhesion following a caesarean section is variable and influenced by numerous factors15. Intraoperative adhesions that do not impede the surgical procedure may be left unaddressed. Previous studies have reported that MRI or ultrasound can be used to assess pelvic adhesions before a second caesarean section16,17; however, the utility of these imaging modalities for predicting adhesions prior to SILS via a transabdominal scar approach requires further investigation. The umbilical cord presents a more limited array of incisions, accompanied by a significant increase in postoperative incisional hernias. This differs from the traditional caesarean section scar approach, which allows extension along the preexisting scar. However, further case studies are needed to determine the incidence of subsequent incisional hernias.

Surgical field exposure is a key factor in surgical success. Single-incision laparoscopic suspension technology remains the mainstream method for addressing surgical field visibility challenges, reducing the reliance on auxiliary ports. The surgeon first peels back part of the serosal layer of the gallbladder base and uses the remaining gallbladder wall to secure the suspension wire. Establishing ideal exposure during the initial surgery can increase the surgeon’s confidence and improve the success rate of the surgery, especially for patients with a history of right upper quadrant surgery. The anatomical structure reduction process is time-consuming, and the use of suspension technology can significantly reduce intraoperative collateral damage. Some patients with a history of right upper quadrant surgery experience a natural suspension effect because of adhesions between the diaphragmatic surface of the liver and the parietal peritoneum.

Laparoendoscopic single-incision surgery (LESS) has focused on the “chopstick effect” since its inception because of the inherent challenges of instrument operation. Traditional views often consider this effect as a technical limitation, but recent advances may allow strategic application of the “chopstick technique”. Yuya Dou et al.11 described the “chopstick technique” as the way Asians hold chopsticks and applied it to single-incision laparoscopic hysterectomy. In this study, the “chopstick technique” assisted in the removal of bile duct stones. The surgeon holds a precurved suction device in the right hand and a blunt instrument in the left hand. Through collaborative operation, larger CBD stones are effectively pushed upwards through the CBD incision. This method not only promotes stone removal but also makes up for the technical limitations of flexible choledochoscopy.

Notably, SILS is often associated with a prolonged operation time. The operative time of this study was 160.00 (131.25, 185.00) minutes, and the caesarean scar approach was farther from the target; in particular, sharp instruments entering the abdominal cavity require camera guidance to avoid damage to the intestine and omentum, which means that the operative time is prolonged.

Previous reports have shown that the incidence of bile leakage in SIL-CBDE ranges from 1.4% to 7.7%. Chuang et al.9 reported a 1.4% incidence of minor bile leak because of choledochorrhaphy in 146 cases, all of which were classified as Grade II. In this study, one patient (5.56%) experienced bile leakage during the initial phase, which was classified as Clavien–Dindo grade I. During surgery, a needle-hole leak was identified at the suture site. The bile duct measured 8 mm in diameter, posing a challenge for wide-edge suturing. Although some patients did not undergo indwelling prophylactic drainage, the authors recommend placement for those at high risk for bile leakage, such as those with recent cholangitis, pancreatitis, a normal bile duct diameter, and previous right upper quadrant surgery. In the absence of a prophylactic drainage tube, close observation of postoperative abdominal signs is essential to ensure timely detection and intervention. Notably, initial manifestations of bile leakage may not be apparent in some patients, and preemptive analgesia may mask the condition or misinterpret it as surgical trauma. Combined monitoring with colour Doppler ultrasound and postoperative inflammatory markers is recommended.

SIL-CBDE is complex and requires considerable patience. Therefore, meticulous attention to the indications is essential; careful case selection is paramount, while optimal exposure and dependable suturing techniques are critical for success. Surgeons need to have a rich foundation in laparoscopic surgery and be proficient in the use of choledochoscopy and single-incision laparoscopic surgical skills; the author’s experience with SIL-CBDE represents a process of continuous evaluation and improvement. The conventional laparoscopic single-incision approach may only be a transition, and robotic single-incision approaches are expected to make up for the limitations of single-incision laparoscopy18; thus, we must be prepared.

The small cohort, particularly the subgroup undergoing the transcaesarean scar approach (n = 4), precludes definitive conclusions regarding comparative efficacy. Future multicentre studies with larger samples are warranted to validate these preliminary findings. The modest cohort size (n = 18) constrains the statistical power and generalizability, particularly limiting subgroup analyses (e.g., the transcaesarean scar approach, n = 4). While the study demonstrates technical feasibility, the small sample size reduces the sensitivity to detect smaller but clinically meaningful differences and necessitates cautious interpretation of outcomes. These findings should be validated in larger multicentre studies.

Conclusion

In this retrospective case series, SIL-CBDE was successfully performed via both transumbilical and prior caesarean scar approaches. The technique demonstrated feasibility and safety in carefully selected patients. These preliminary findings support further evaluation of the caesarean scar as an alternative single-incision access route. Larger-scale studies are needed to better define the clinical role and limitations of this technique.