A novel 'wrap-and-patch' omental flap technique for the repair of uretero-uterine fistula: A case report.

A 21-year-old primipara presented with a five-month history of continuous, high-volume, watery vaginal discharge that began immediately following a cesarean section for cephalopelvic disproportion. In the early postpartum period, the discharge was mildly profuse; however, the urinary component was entirely unrecognized as it was misattributed to a slightly heavy lochial flow, especially since her hemoglobin levels remained within the normal range. It was only after the lochia had completely ceased that the persistent watery nature of the discharge became evident, which then transitioned to a bloody appearance only during menstruation. She reported needing to use several pads daily therefore resorted to rather use a nappy due to the copious amount of leakage. She maintained normal antegrade bladder voiding and normal bowel movements. Her medical and surgical history was otherwise unremarkable, with no other known previous gynecologic or obstetric history. Physical examination revealed a well-healed Pfannenstiel incision scar. Inspection of the vulva and perineum demonstrated copious, yellow-tinged, non-offensive fluid actively leaking from the vagina. Upon sterile speculum examination, the fluid was observed actively exiting from the cervical os. Bimanual palpation of the uterus and adnexa revealed no masses, tenderness, or other significant abnormalities. All baseline laboratory studies were unremarkable, including FBC, renal function tests, and CRP. Furthermore, urinalysis and UMCS yielded results within normal physiological ranges, ruling out a concurrent urinary tract infection. A kidney, ureter, and bladder (KUB) ultrasound revealed a normal-appearing right kidney and bladder; however, the left kidney demonstrated grade 3 hydronephrosis. A voiding cystogram showed no vesicovaginal fistula. This was followed by a computed tomography intravenous pyelography (CT IVP), which revealed moderate left uretero-hydronephrosis with the left ureter communicating with and draining into the uterine cavity. Contrast was also noted within the vagina, suggesting a ureteric injury with ureterouterine fistulization ( Fig. 1 a–d). Fig. 1 a-d: Pre-operative CT images a: Axial view - delayed phase of CT abdomen with intravenous contrast showing left hydronephrosis (yellow arrow). b: Axial view - delayed phase of CT abdomen with intravenous contrast showing left proximal hydroureter (yellow arrow) and hydronephrosis (blue arrow). c: Axial view - delayed phase of CT abdomen with intravenous contrast showing dilated left proximal ureter (red arrow). d: Axial view - delayed phase of CT abdomen with intravenous contrast showing a dilated left distal ureter (yellow arrow), communicating with the uterus (red arrow) and contrast in the vagina (blue arrow). The bladder is also filled with contrast (black arrow). Fig. 1 a-d: Pre-operative CT images a: Axial view - delayed phase of CT abdomen with intravenous contrast showing left hydronephrosis (yellow arrow). b: Axial view - delayed phase of CT abdomen with intravenous contrast showing left proximal hydroureter (yellow arrow) and hydronephrosis (blue arrow). c: Axial view - delayed phase of CT abdomen with intravenous contrast showing dilated left proximal ureter (red arrow). d: Axial view - delayed phase of CT abdomen with intravenous contrast showing a dilated left distal ureter (yellow arrow), communicating with the uterus (red arrow) and contrast in the vagina (blue arrow). The bladder is also filled with contrast (black arrow). The patient provided informed consent for examination under anesthesia, cystoscopy, vaginoscopy, and retrograde studies, with possible ureteric reimplantation. Intraoperative findings included no palpable lesions or fistulae on pelvic examination. Cystoscopy revealed a small left ureteric orifice compared to the right, with normal vesical mucosa; however, neither a guidewire nor a ureteric catheter could be advanced through the orifice into the left ureter. Vaginoscopy demonstrated a posterior vaginal wall indentation, through which a guidewire also failed to pass. Retrograde studies showed an abrupt halt of contrast in the distal left ureter ( Fig. 2 ). Fig. 2 Pre-reimplantation retrograde pyelography The fluoroscopic image, obtained prior to ureteral reimplantation, demonstrates an abrupt halt of contrast in the distal left ureter (white arrow), indicating the site of the missed injury. Fig. 2 Pre-reimplantation retrograde pyelography The fluoroscopic image, obtained prior to ureteral reimplantation, demonstrates an abrupt halt of contrast in the distal left ureter (white arrow), indicating the site of the missed injury. Given these findings, a left uretero-neocystostomy was performed over a double-J (DJ) stent following the excision of the fistulous fibrous tract. To ensure a robust repair, we employed a novel 'Wrap-and-Patch' omental technique, consisting of a pedicled omental wrap around the ureteral anastomosis and a double-layered omental interposition patch over the repaired defect on the posterior uterine wall ( Fig. 3 a–e). Six weeks postoperatively, the patient returned for left retrograde studies, which confirmed a patent ureter ( Fig. 4 a and b), and the stent was removed. Follow-up CT IVP, performed after stent removal, revealed no evidence of ureteric stricture, contrast extravasation, or recurrent UUF ( Fig. 5 a–c). At the last review three months later, the patient was asymptomatic with no hydronephrosis on ultrasound. Fig. 3 a-e: Intraoperative Images a: The left ureter (white arrow) is shown following circumferential dissection and mobilization. b: Intraoperative view of the fistula site. The anatomical relationship between the uterus (Blue arrow), the left ureter (yellow arrow), and the dense fibrotic fistulous tract (white arrow) is demonstrated. c: An omental patch (orange arrow) is secured over the posterior uterine wall (black arrow) to close the fistulous opening and provide a well-vascularized biological seal. d: Left ureteroneocystostomy . Intraoperative view showing the successful reimplantation of the left ureter into the bladder (black arrow). The white arrow indicates the specific site of the ureterovesical anastomosis. e: Intraoperative view showing the omental flap circumferentially wrapped over the ureteroneocystostomy site. Fig. 3 Fig. 4 Retrograde pyelography post reimplantation and fistula repair a demonstrates a patent left distal ureter (yellow arrow) with successful passage of contrast into the ureter and no evidence of extravasation or stenosis immediately after reimplantation. b demonstrates a patent left ureter with successful passage of contrast into the ureter and no evidence of extravasation or stenosis 6 weeks post op. Fig. 4 Fig. 5 a-c. Post-operative CT Urogram after stent removal. a: Axial excretory phase image demonstrating the absence of hydroureter on the left. b: Axial excretory phase image showing the distal left ureter (blue arrow) coursing anteriorly following surgical reimplantation. c: Axial excretory phase image showing contrast within the bladder (red arrow) with no evidence of extravasation into the uterus or vagina, confirming successful fistula repair. Fig. 5 a-e: Intraoperative Images a: The left ureter (white arrow) is shown following circumferential dissection and mobilization. b: Intraoperative view of the fistula site. The anatomical relationship between the uterus (Blue arrow), the left ureter (yellow arrow), and the dense fibrotic fistulous tract (white arrow) is demonstrated. c: An omental patch (orange arrow) is secured over the posterior uterine wall (black arrow) to close the fistulous opening and provide a well-vascularized biological seal. d: Left ureteroneocystostomy . Intraoperative view showing the successful reimplantation of the left ureter into the bladder (black arrow). The white arrow indicates the specific site of the ureterovesical anastomosis. e: Intraoperative view showing the omental flap circumferentially wrapped over the ureteroneocystostomy site. Retrograde pyelography post reimplantation and fistula repair a demonstrates a patent left distal ureter (yellow arrow) with successful passage of contrast into the ureter and no evidence of extravasation or stenosis immediately after reimplantation. b demonstrates a patent left ureter with successful passage of contrast into the ureter and no evidence of extravasation or stenosis 6 weeks post op. a-c. Post-operative CT Urogram after stent removal. a: Axial excretory phase image demonstrating the absence of hydroureter on the left. b: Axial excretory phase image showing the distal left ureter (blue arrow) coursing anteriorly following surgical reimplantation. c: Axial excretory phase image showing contrast within the bladder (red arrow) with no evidence of extravasation into the uterus or vagina, confirming successful fistula repair.

Mohammed Salah E. Khalifa Salem: Writing – original draft. Alain Mwamba Mukendi: Writing – review & editing, Writing – original draft, Resources, Methodology, Conceptualization of cyclical hematuria classification system. Zakithi Cele-Mbuthweni: Writing – original draft.

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Consent to publish the case report was obtained from the patient.

All authors attest that they meet the current ICMJE criteria for authorship.

This report presents a successful surgical strategy: the ‘wrap-and-patch' omental flap technique for the repair of UUF. This technique addresses the most critical failure points in UUF repair: anastomotic leakage and uterine-ureteric communication as well as the challenges presented by tissue fibrosis, a common complication in both the natural history of the condition and conventional repairs. This single-procedure method offers a promising approach in the absence of universal guidelines and suggests potential for improved outcomes and reduced recurrence rates, warranting further research and long-term follow-up to fully validate this technique and establish its role in standard clinical practice.

The diagnosis of UUF remains a challenge due to its extreme rarity accounting for less than 6% of urogenital fistulas and the ambiguity of its early clinical presentation. 1 While UUF can present early in the postoperative period, it is not uncommon for symptoms to appear weeks later. This delay is frequently attributed to the mechanism of injury; direct ureteric insults (transection or laceration) often result in early urinary leakage, while ischemic injury caused by ligation or devascularization requires time for tissue sloughing and fistula formation to occur. 1 , 2 In this case, the diagnosis was complicated by a significant pitfall: the masking of urinary leakage by mildly profuse postpartum lochia in the presence of stable hemoglobin levels and normal urethral voiding. This clinical picture aligned with the classic presentation of UUF, which is characterized by paradoxical urinary incontinence. 1 , 2 , 4 Interestingly, as the postpartum period progressed, our patient's watery discharge transitioned to a cyclic bloody appearance occurring exclusively during menstruation. Jozwik et al. introduced a clinical classification of vesicouterine fistula (VUF) based on the patterns of menstrual flow. They categorized VUF into three types: Type I (Youssef syndrome) characterized by menouria, amenorrhea, and complete urinary continence. Type II involves both menouria and normal vaginal menses with intermittent urinary leakage, while Type III presents with normal vaginal menses and intermittent leakage but lacks menouria. 5 , 6 Alain Mwamba Mukendi , one of the authors of this paper proposes a classification for cyclic hematuria (menouria) based on the confluence of menstrual blood and urine within either the urinary or genital tract and whether the discharge exits via the urinary or genital route, provided a mixture of both fluids has occurred: • Type 1: Cyclic hematuria (menouria) - 1a without a urogenital fistula or urinary incontinence (e.g., vesical endometriosis). - 1b: with a urogenital fistula but without urinary incontinence (e.g., Youssef syndrome or certain Müllerian anomalies). • Type 2: Cyclic hematuria (menouria) with a urogenital fistula and associated urinary incontinence (e.g., ureterouterine, ureterovaginal, vesicovaginal, or complex vesicouterine fistulae). Type 1: Cyclic hematuria (menouria) 1a without a urogenital fistula or urinary incontinence (e.g., vesical endometriosis). 1b: with a urogenital fistula but without urinary incontinence (e.g., Youssef syndrome or certain Müllerian anomalies). Type 2: Cyclic hematuria (menouria) with a urogenital fistula and associated urinary incontinence (e.g., ureterouterine, ureterovaginal, vesicovaginal, or complex vesicouterine fistulae). By utilizing this diagnostic algorithm as a clinical triage tool, the presence or absence of urinary incontinence acts as a critical branch point in the diagnostic workup. Its absence suggests Type 1 menouria, whereas its presence identifies Type 2. UUF can be suspected with the observation of urine dribbling from the external cervical os during speculum examination, a three-swab test, and cysto-panendoscopy. The triple swab test remains an important diagnostic test in the evaluation of urogenital fistulae. This procedure involves placing three distinct swabs at the superior, middle, and inferior levels of the vaginal canal. Subsequently, a diluted solution of methylene blue is instilled into the bladder. After a period of 10 to 30 minutes the swabs are extracted and inspected. The finding of a wet but unstained uppermost swab is highly suggestive of a uretero-genital fistula. 2 Sheen et al. modified the swab test by utilizing phenazopyridine every 8 hours, followed by the installation of 200 cc of methylene blue into the bladder after 24 hours; orange urine from the vaginal swabs confirms UUF and excludes a vesicovaginal fistula. 1 , 4 While CT urography is instrumental in localizing ureteric injuries, detecting extravasation, and assessing renal function, retrograde ureteropyelography (RGP) remains a critical diagnostic adjunct. RGP provides superior visualization of the distal ureteric segment often poorly opacified on antegrade imaging thereby allowing for a precise assessment of ureteric continuity to guide surgical or endoscopic intervention. 4 In our case, a CT Urography demonstrated the fistulous communication between the ureter and the uterus; furthermore, subsequent retrograde studies revealed an abrupt halt of contrast in the distal left ureter. This experience emphasizes that a definitive diagnosis of UUF requires a high index of clinical suspicion and specialized testing rather than reliance on early symptoms alone. The extreme rarity of this condition has precluded the development of standardized treatment guidelines, thereby necessitating a highly tailored management strategy for each individual case. 2 The management of UUF aims to restore ureteral continuity, preserve renal function, and repair the uterine perforation, while preventing complications such as urine leakage, infection, and tissue necrosis. Conservative and minimally invasive options, such as percutaneous nephrostomy and endoscopic JJ stenting, are preferred for early-presenting cases and can lead to spontaneous healing. Conversely, definitive surgical repair remains the mainstay for delayed presentations or cases where endourological interventions fail. 1 , 2 , 4 , 7 In the literature, while percutaneous nephrostomy (PCN) has successfully ensured urine diversion and complete UUF healing in select cases, it often fails to provide definitive resolution, necessitating subsequent surgery. In contrast, internal JJ stenting demonstrates a higher rate of success, functioning as a definitive treatment in a few reported instances while failing in a smaller subset. Consequently, surgical repair remains the gold standard and the mainstay of treatment for over 68% of cases, particularly following failed conservative management or in delayed presentations. The surgical approach whether performed via open, laparoscopic, or robot-assisted techniques is tailored to the fistula's location, the length of the involved ureteric segment, and the degree of local fibrosis. Reconstructive options typically involve the excision of fibrotic tissue, closure of the uterine defect, uretero-ureterostomy, or ureteroneocystostomy with or without a psoas hitch or Boari flap, with specialized techniques such as human dura mater allograft ureteroplasty also reported 1 , 2 , 3 , 4 , 7 . In our specific case, fibrotic tissues in the distal ureter and the left lateral posterior uterine wall were excised, followed by closure of the uterine defect, ureteroneocystostomy over a JJ stent, and the innovative use of an omental flap in a 'wrap and patch' fashion. We applied the novel 'Wrap-and-Patch' omental flap technique, which employs a pedicled omental flap for a dual-surface protection strategy. The first component, the omental wrap, involved circumferentially wrapping the uretero-neocystostomy. This 360-degree biological sleeve provided immediate neovascularization to the anastomosis, which is critical for preventing ischemia and reducing the risk of stricture formation a common complication following ureteral repairs. We argue this strategy is superior to simple repair, particularly in compromised tissue environments. Simultaneously, the second component involved a double-layered omental patch applied to the uterine defect to maximize structural and functional integrity. The deep layer of this patch functioned as an overlay, providing direct vascular reinforcement to the primary uterine suture line to accelerate healing. Overlaying the omentum in this manner ensures the repair site receives a constant blood supply, even in the presence of postoperative inflammation. The superficial layer served as a true interposition barrier. By creating a mechanical and immunological buffer between the repaired uterus and the urinary tract, this layer prevented direct apposition and subsequent epithelialization of both ureteral and uterine mucosal surfaces that typically drives fistula recurrence. We define the 'Wrap and Patch' technique by this clear distinction: the wrap provides a biological seal for the ureteral anastomosis, while the double-layered patch provides both vascular reinforcement (overlay) and a physical barrier (interposition) to prevent the uterine defect from communicating with the urinary tract during the delicate healing phase. This multi-layered approach justifies the novelty of our repair and provides a robust framework for managing complex urogenital communications.

Iatrogenic ureteric injury remains a rare but serious complication of obstetric and gynecological procedures, occurring in approximately 0.5%–1% of cases and rising to 2% during radical hysterectomies. While most injuries are recognized intraoperatively, unrecognized trauma can lead to the development of a uretero-uterine fistula (UUF). These fistulas are relatively rare, constituting less than 6% of all urogenital fistulas, and most frequently follow Cesarean sections. 1 , 2 Several factors predispose the ureter to such injuries, including pelvic fibrosis and anatomical displacement from previous surgeries, uterine dextro-rotation which may explain the higher incidence of left-sided involvement and prolonged, obstructed labor leading to tissue edema and necrosis. Anatomically, the lower third of the ureter is particularly vulnerable; it may be compromised by low transverse uterine incisions, excessive lateral extensions, or inadvertent suture ligation. Such maneuvers can lead to hematoma formation and infection, eventually resulting in the formation of a fistulous tract between the injured ureter and the uterus. Clinically, UUF classically presents with paradoxical urinary incontinence despite preserved normal urethral voiding. 1 , 2 The biological profile of the omentum, particularly when utilized as a pedicled flap, fulfills the essential requirements for effective integration during urogenital tract reconstruction The biological profile of the omentum, particularly when utilized as a pedicled flap, fulfills the essential requirements for effective integration during urogenital tract reconstruction.Its multifaceted role in promoting angiogenesis, providing a biological seal, and facilitating epithelial and muscle regeneration, combined with its innate anti-inflammatory properties, makes it particularly effective for reinforcing repairs in complex pelvic and urogenital fistulas. 3

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.