Transanal ligation of fistula during laparoscopically assisted anorectal pull-through for rectourethral bulbar fistula—a case series

Introduction

Despite advancements in techniques and the utilization of various surgical methods, male patients with congenital rectourethral fistula (RUF) still encounter surgical challenges. In recent years, numerous studies and discussions have centered around the application of laparoscopically assisted anorectal pull-through (LAARP) and the conventional posterior sagittal anorectoplasty (PSARP) surgery in the management of RUF. LAARP surgery is mostly used for treating RUF in boys with high/intermediate-type imperforate anus (1), which was first described over 20 years ago by Georgeson (2). This procedure offers several advantages, including minimal scarring, reduced surgical trauma, enhanced visualization, and the prevention of disruption to posterior sagittal sphincter function. However, achieving laparoscopic isolation and accurate ligation of the rectourethral bulbar fistula (RUBF) situated beneath the peritoneal retroflection demands a high degree of surgical expertise. Simultaneously, concerns regarding urethral injury have led to premature termination of dissection in some cases, prior to reaching the RUF (3,4). Due to the increased length of the residual tissue, the residue remaining from the original fistula is called a posterior urethral diverticulum (UD) (5), which is a common complication of LAARP surgery (6). We believe that the theoretical risk of UD formation can be minimized through the complete excision of the fistula at the distal end of the rectum and through precise ligation of the fistula to prevent the retention of excess tissue.

In this study, we elucidate a surgical technique for transanal ligation of RUBF and investigate its efficacy in mitigating urethral complications related to a remnant of the original fistula (ROOF) when employing LAARP surgery for RUBF. We present this article in accordance with the AME Case Series reporting checklist (available at https://tp.amegroups.com/article/view/10.21037/tp-2025-415/rc).

Case presentation

Patient information

This retrospective case series included four male patients with RUBF who underwent transanal fistula ligation during LAARP at Beijing Children’s Hospital between October 2019 and December 2022. All patients had received initial diverting colostomies either at our institution or referring hospitals during the neonatal period, followed by definitive LAARP with concurrent transanal fistula repair 2–3 months later. Preoperative evaluation included pelvic magnetic resonance imaging (MRI) and contrast fistulography (Figure 1). Colostomy closure was performed 1.5–3.5 months post-LAARP at either our center or local hospitals.

Figure 1 Preoperative imaging examination data. (A) Preoperative MRI examination. (B,C) Preoperative contrast fistulography. MRI, magnetic resonance imaging.

We collected comprehensive demographic and clinical data, including (I) neonatal parameters: birth weight and associated congenital anomalies; (II) family history of anorectal malformations (ARMs); (III) surgical parameters: age and weight at LAARP, operative duration; and (IV) postoperative outcomes: duration of urinary catheterization and hospitalization.

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Medical Ethics Committee of Beijing Children’s Hospital (approval No. 2023-E-136-R). Written informed consent was obtained from all legal guardians prior to surgical intervention and the publication of this case series and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Surgical technique

Following induction of general anesthesia, the patient was positioned supine, and a urinary catheter was inserted. A four-port laparoscopic technique was employed, consisting of a 5-mm optical trocar, a 3-mm working port in the left lower quadrant, and two additional 3-mm ports at the right anterior superior iliac spine and McBurney’s point. CO₂ pneumoperitoneum was established and maintained at 8–10 mmHg. The bladder was suspended using a traction suture to optimize exposure.

Laparoscopic dissection proceeded from the peritoneal reflection to the RUF, with careful separation of the fistula at its urethral entry point. The secondary vascular arch of the sigmoid colon was mobilized to ensure tension-free straightening of the distal rectum.

The surgical team then addressed the perineal phase. Electrical stimulation was used to locate the contraction center of the anal sphincter before incising the overlying skin. Using curved forceps, preserves sphincter muscles by creating a passage through the center without division, until pelvic entry was achieved. The rectal fistula was ligated and divided. The distal rectum was exteriorized through the perineal incision, trimmed, and reconstructed via interrupted 4-0 absorbable sutures to complete the anoplasty.

Transanal ligation of fistula during LAARP surgery

After separating the fistula along the perirectal area distally at the point where the fistula entered the urethra. The operator turned to the perineum, using curved forceps, thread a silk through the tunnel established at the center of the sphincter complex into the pelvic region. Keep the forceps steady, use laparoscopic instruments to loop the suture around the separated rectal fistula once, and then pass the suture back to the forceps, securing it tightly to prevent excessive tissue ligation. Perform deep knotting at the perineum, inserting a finger into the anal sphincter tunnel to advance the suture, securely ligating it at the point where the fistula merges with the urethra (Figure 2). Cutting off the fistula under direct laparoscopic visualization. A muscle cuff was left to prevent urethral injury. Under laparoscopic magnification, three interrupted sutures were placed on the lateral aspect of the urethra using 5-0 PDS suture to achieve complete coverage of the fistula opening (Figure 3).

Figure 2 Transanal ligation of fistula during LAARP for RUBF. (A) The white arrow indicates the ligation position under laparoscopic monitoring. (B) Ligate the fistula outside the body. LAARP, laparoscopically assisted anorectal pull-through; RUBF, rectourethral bulbar fistula.

Figure 3 The white arrow indicates the fistula opening was intermittently sutured using 5-0 PDS suture. PDS, polydioxanone.

Follow‑up method

Initially, a comprehensive evaluation was conducted involving physical examinations, pelvic MRI scans, and a retrograde urethrogram (RUG) to screen pediatric patients for potential postoperative complications. This assessment occurred within a window of 1.5 to 3.5 months following the LAARP procedure. Subsequently, follow-up examinations are conducted after colostomy closure. During these assessments, pertinent data concerning defecation and urinary functions were gathered from the parents or guardians of the pediatric patients. Given the young age of the children, the evaluation of gastrointestinal function primarily focused on identifying symptoms such as constipation, fecal incontinence, or any specific dietary requirements. In regard to urinary function, the assessment revolved around determining whether the children exhibited spontaneous urination, required intermittent catheterization, experienced dysuria, or maintained continence between voiding episodes.

Results

A retrospective analysis was conducted on patient data, surgical outcomes, and prognostic factors in four pediatric cases that underwent transanal ligation of fistula during LAARP surgery for RUF (Table 1).

The median birth weight of these children was 3,650 (range, 3,400–4,600) g, and none of them had a family history of ARM disease in their relatives. The median age at the time of the LAARP procedure was 65 (range, 52–115) days, with a median body weight of 5,850 (range, 5,700–8,500) g at the time of surgery. The median duration of each surgical procedure was 115 (range, 100–130) minutes. Based on statistical analysis, all four children had a postoperative urinary catheter retention time of 8 days, as well as a postoperative discharge time of 8 days.

Prior to anastomosis closure, all four children underwent pelvic MRI and urethral contrast examinations, which reported no postoperative complications (Figure 4). Subsequent follow-up examinations following colostomy closure indicated favorable prognoses, with satisfactory anal appearance in all cases (Figure 5). Only one child experienced fecal incontinence less than once a week, and at the last follow-up, the child’s fecal incontinence symptoms had significantly improved with a Rintala score of 17. Urinary function follow-up demonstrated positive outcomes, with no indications of UD or stenosis in any of the children. None of the four children required intermittent catheterization or experienced dysuria, and all maintained continence between urination sessions. Detailed follow-up information is presented in Table 1.

Figure 4 Postoperative imaging examination data. (A) Postoperative review of pelvic MRI. (B) RUG. MRI, magnetic resonance imaging; RUG, retrograde urethrogram.

Figure 5 Anal appearance at 50 days postoperatively.

Discussion

The anatomical spectrum of ARMs and associated genitourinary anomalies demonstrates significant gender-specific variation, with RUF representing the most common subtype in male patients (7). Current surgical management of RUF primarily involves either the LAARP or the conventional PSARP approach.

LAARP has gained widespread adoption as a minimally invasive technique capable of addressing complex malformations. Compared to PSARP, LAARP offers distinct advantages, including enhanced fistula visualization and precise anatomical placement of the pull-through segment within the pelvic floor musculature without requiring muscle division (8,9). The laparoscopic approach may additionally reduce the risk of injury to pelvic neural plexuses.

However, contemporary evidence fails to demonstrate LAARP’s superiority over traditional techniques regarding long-term fecal continence outcomes (7,10,11). Emerging data suggest potential limitations of LAARP, including greater procedural invasiveness and increased risk of complications, particularly when the rectal pouch is positioned inferior to the peritoneal reflection (7,12). These findings have prompted recommendations for careful patient selection when considering LAARP for RUBF cases (12,13).

The selection of the precise location for ligating the fistula holds significant importance for the surgeon during the LAARP procedure. If the RUF is situated in close proximity to the urethra, there is a heightened risk of inadvertent damage to the urethra or its blood supply, potentially leading to the development of urethral stricture (14). Considering this issue, the surgeon must carefully assess the positioning of the rectal fistulous tract relative to the urethra. An incorrect ligation site, either too distant from the urethra or insufficient separation of the distal rectum from the urethra, can result in the formation of a UD (3). An analysis included in a systematic review of postoperative complications following laparoscopic-assisted anorectoplasty (15) revealed that UD was among the most common complications, occurring in 3.02% of cases. It is worth noting that the actual incidence of UD may be underestimated due to undetected clinical symptoms or asymptomatic patients. This colonic mucosal diverticulum is prone to issues such as urinary dribbling, stone formation, and infection, with isolated cases even demonstrating the occurrence of cancer within the diverticulum (16).

The urethrorectal common wall (CW) in males with ARMs and RUBF demonstrates complex anatomical relationships. Emerging evidence indicates that variations in fistula morphology—particularly a more acute insertion angle of the rectal fistula—may contribute to an elongated urethrorectal CW, potentially predisposing to UD formation (3). However, other studies have indicated that the CW length in RUBF is not significantly different from that in other malformations (12,17). Regardless of the prevalence of longer CWs in RUBF, urethrobulbar fistulae and lower-located fistulae are associated with difficulty in visualizing and ligating fistula maneuvers under laparoscopic manipulation. Even if the end of the rectal fistula has been precisely isolated to merge into the urethra, due to the CW and the small angle of the insertion of the rectal fistula into the urethra. When tying a knot in the child’s pelvis using laparoscopic instruments, it is still not possible to completely tie the knot to the root of the distal fistula due to the upward direction of the force, which produces a retained ROOF, creating a UD (Figure 6). With the accumulation of experience in LAARP surgery, we found that suspension of the bladder can better expose the field of view of laparoscopic separation, and RUBF can be used to ligate the fistula in the perineum under laparoscopic surveillance by entering the pelvis with curved forceps in the center of the sphincter complex to introduce a silk thread after the laparoscopic rectal dissection was performed from the peritoneal reflection to the RUF. The advantage of this method is that the knot is tied in the direction of the patient’s perineum. The silk thread wrapped around the rectal fistula can be securely hung at the confluence of the rectal fistula into the urethra and achieve appropriate ligation location at the urethro-rectal junction. By tying a deep knot from the anus, it is possible to ensure that the rectal fistula distal to the CW is ligated completely and accurately, and that the direction of ligation is parallel to the urethral course, reducing the possibility of UD (Figure 7).

Figure 6 Ligation of fistula with laparoscopic instruments (UD in green). UD, urethral diverticulum.

Figure 7 Transanal ligation of fistula. The arrows indicate the direction of the applied force.

The surgical techniques described in this study provide some assistance in the surgical approach to the treatment of RUBF using the LAARP surgery and may reduce the difficulty of utilizing the LAARP procedure for the treatment of RUBF. In recent years, with the development of minimally invasive surgical techniques, some other techniques such as intraluminal dissection, opening into a distal UD, the junction between the rectum and the urinary tract can be accurately identified under direct vision, and the rectal mucosa can be completely removed, preventing UD and urinary tract injuries (4); by injecting indocyanine green (ICG), the ICG-guided LAARP procedure allows safe and precise localization of the terminal rectal fistula, while facilitating laparoscopic separation and resection (18). These and the surgical techniques for transanal ligation of fistulae described in this article can provide more detailed and comprehensive assistance to the surgeon performing LAARP for ARMs in order to minimize the potential of complications. With the help of these new surgical techniques, even some low imperforate anus can be considered for treatment with the LAARP surgery. The LAARP surgery will become even more of a choice for physicians, especially since it also has the advantage of eliminating the need to incise the sphincter complex and avoiding the possibility of nerve damage.

Conclusions

In conclusion, we believe that the LAARP surgical technique of transanal fistula ligation is effective and convenient for RUBF. Moreover, it can theoretically reduce the incidence of urologic complications such as UD. By combining this with other surgical techniques and new approaches, it is possible to reduce the operational difficulty of treating RUBF using LAARP surgery, reduce complications, and avoid the damage to nerves and muscles caused by PSARP surgery. This study has some limitations. Our study had only a small number of participants. However, we believe this technique can be generalized and applied to a larger number of patients. In the future, larger case and control samples as well as robust statistical analyses with longer-term follow-up results may be needed to determine whether transanal ligation of fistula during LAARP surgery significantly reduces the complication rate.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the AME Case Series reporting checklist. Available at https://tp.amegroups.com/article/view/10.21037/tp-2025-415/rc

Peer Review File: Available at https://tp.amegroups.com/article/view/10.21037/tp-2025-415/prf

Funding: This study was supported by Beijing Municipal Science & Technology Commission (No. Z211100002921062) and Beijing Municipal Natural Science Foundation (No. 7252043).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tp.amegroups.com/article/view/10.21037/tp-2025-415/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Medical Ethics Committee of Beijing Children’s Hospital (approval No. 2023-E-136-R). Written informed consent was obtained from all legal guardians prior to surgical intervention and the publication of this case series and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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