[Abstract] Objective To investigate the clinical characteristics and diagnosis and treatment of single ureteral ectopic opening in girls. Methods To summarize and analyze the clinical data of 3 cases of single ureteral ectopic opening in girls. The main clinical manifestations were dribbling incontinence, ectopic renal dysplasia and heterotaxy in 2 cases and hydronephrosis in 1 case. Ultrasound and IVU play an important role in the diagnosis and management of this disease, and surgical resection of the affected kidney and ureter is effective. Keywords ureter, ectopic opening, urinary incontinence, diagnosis, treatment Ureteral ectopic opening is a common urological abnormality in pediatric patients, often combined with heavy kidney and double ureter, single ureteral ectopic opening is relatively rare, especially in girls [1]. Three cases of girls with a single ectopic ureteral opening were admitted to our hospital and are reported below. Clinical data Case 1 Female, 3 years and 6 months old. The child had normal urination since standing and walking, but the urethra dripped intermittently and often wet her clothes and pants during the day. For the past 2 years, eczema has appeared on the perineum. Ultrasound showed hydronephrosis in the right kidney, and high-dose intravenous urography showed vague shadowing of the right kidney. perineum. The right kidney and part of the ureter were resected, and the wound healed in one stage after surgery. Pathologic diagnosis: chronic montanous nephritis of the right kidney, hydronephrosis, chronic ureteritis and ureteral dilatation. Case 2 Female, 5 years old. She had normal urination with a soaked diaper, intermittent urine dripping from the vaginal orifice since the age of 3 years, frequent eczema in the perineum, decreased urine leakage over the past year, only intermittent small amount of urine leakage during the day, ultrasound reported compensated hyperplasia of the right kidney, no kidney detected in the left renal area, dilated left ureter detected in the left posterior part of the bladder, connected to the small kidney and not accessible to the bladder downward, high-dose intravenous urography delayed to 2h, 8h, 36h films were not No renal visualization was seen in the kidney. Under general anesthesia, the vagina was observed with a nasal speculum and a papillary protrusion was seen in the anterior wall near the fornix, and an epidural catheter was unsuccessfully inserted. Under basic + continuous epidural anesthesia, the left kidney was explored through an oblique incision in the left lower abdomen, and the left ureter was seen to be superior to the left side of the bladder without crossing the iliac vessels and turning medially to the posterior and upward, against the anterior spine, with a small kidney of about 3x2x1cm at the level of the flat umbilicus, with a cyst on the surface, and the total length of the ureter was 14 cm, with a thick and stiff wall and little peristalsis. Postoperatively, the wound healed in one stage, and the urinary leakage and perineal eczema disappeared. Case 3 Female, 2 years old. There was normal urination with loss of urine, less at night than during the day. High-dose intravenous urography showed irregular left renal pelvis, small left kidney, flat 3rd lumbar thrust level, and ureteral pathway close to normal pathway. The right kidney and ureter were well visualized. Hysteroscopic vaginal examination was performed under separate anesthesia. An epidural catheter was unsuccessfully inserted. A balloon catheter (F6) was inserted into the vagina, 1 ml of air was injected into the balloon, and the hand was pulled slightly outward to close the external vaginal opening. The morphology was the same as that of intravenous angiography. The diagnosis was left renal dysplasia, ectopic and left ureteral ectopic opening. Ultrasound examination was performed later to confirm the above diagnosis. The left kidney and part of the ureter were removed through a right rectus abdominis incision. The pathology report was chronic inflammation of the left kidney and ureter. About 80% of ureteral ectopic openings are combined with duplicated kidney and duplicated ureteral malformation, and most of them are from the ureter of the superior kidney [2]. The main clinical manifestation is persistent postnatal leakage of urine with normal fractionated voiding. It can occur in both men and women. In men, the ectopic opening is always on the external sphincter, whereas in women it is located distal to the bladder neck and sphincter, so female cases are detected by visits for urinary leakage, whereas male cases are difficult to detect. The three cases in this group were all female with similar clinical symptoms, but due to the concealed ectopic opening, they were misdiagnosed as “enuresis” and suffered from long-term urine leakage. It is important to raise the awareness of this disease and manage it early for the physical and mental health of patients. The disease also has the following clinical and pathological features: (1) the kidney is small in size, because the renal vessels and ureter are too short, the kidney is located low, often near the entrance of the pelvis and near the spinal column; (2) the kidney tissue is poorly developed, microscopically there are a large number of immature dilated ducts, the number of glomeruli and tubules is small, the arrangement is abnormal and poorly developed; (3) the child has no other clinical manifestations except for dripping wet pants, and the degree of dripping wet pants is much higher than that of The degree of urine dripping and wetting is much lighter than those with heavy kidney and double ureter combined with ureteral ectopic opening. Ureteral ectopic opening is a result of abnormal embryonic development of the renal system. Ureteral buds originating from the middle renal duct commonly show three kinds of abnormalities: (1) bifurcation in the middle to produce “bifurcated ureter”; (2) additional buds are sent out to form “duplicated ureter”. If the two buds are close to each other in the middle renal canal, they will open close to each other in the bladder. If the two buds are farther apart or the ureteral buds in the upper renal segment are more closely attached to the Wufei system and cannot be detached, they will bring the ureter that drains the high renal pelvis to a location outside the bladder to form a ureteral ectopic opening; (3) a single ureteral bud emanates in an abnormal location to form a single ureteral ectopic opening. The pathogenesis of the single ureteral ectopic opening was different in the three cases we admitted: cases 2 and 3 were probably due to the high location of the single ureteral bud that emanated from the middle renal duct and entered the lower part of the urogenital sinus with the Wufei’s system during migration and was merged with the Mullerian duct that entered the urogenital sinus first, and the end of the Mullerian duct was involved in forming the vaginal fornix, so the ectopic opening was located in the vaginal fornix. In contrast, in case 1, the single ureter was brought to the urethra during embryonic development when the single ureter and the midrenal duct below its initiation merged into the bladder due to an imbalance in cell proliferation and failed to achieve the normal positional transformation. Ectopic opening of the single ureter is more commonly seen in men and is often accompanied by an underdeveloped kidney. There is usually a marked reduction in bladder capacity, often with reflux, and severe dribbling incontinence in children. The obstruction impairs the blood supply to the affected renal segment and renal hypoplasia occurs. mackie and Stephens stated that the lower the ectopic opening of the ureter, the worse the renal development [3, 4], while a study by Wakhlu et al. in India found little association [5]. Example 1 The right ureter opens at the constricted part of the urethra and must overcome the urethral closure pressure to deliver urine. Over time, that side of the ureter and kidney became fluid-filled, with tortuous, elongated ureter and infection. Mackie found that the location of the ectopic ureteral opening was closely related to the radiographic appearance of the kidney and renal morphology. Openings in the ureter or genital tract are often accompanied by dilated and tortuous ureters and malformed small kidneys. Examples 2 and 3 were accompanied by dysplastic ectopic kidneys. Intermittent dribbling of urine in girls who have been trained to urinate in the toilet is a diagnostic sign of the disease. Prolonged infection causing obstruction at the end of the ureter and causing decreased renal function can reduce the symptoms of dripping urine. The dilated ureter acts as a reservoir when lying down, and the increase in urine flow when pressing the abdomen or standing is the result of the outflow of urine from the “reservoir”. The history is important in the diagnosis, and the disease should be considered in female patients who present with persistent overflow of urine in addition to normal urination. The key to diagnosis is to find the ectopic opening according to the anatomical features. The common sites of ectopic openings are urethra, vagina and vestibule, because the leak is small, and the kidney it drains is often poorly functioning and produces little urine, so the examination is done in a lithotomy position to fully expose the perineum and squeeze the kidney area and ureter to increase the leak to help find it; about 80% of cases can be accurately diagnosed by high-dose IVU, ultrasound and retrograde imaging of ectopic openings of different types and localization. However, there are still about 20% of patients in whom the type and localization cannot be determined because of impaired renal function due to ectopic opening ureteral drainage or the low concentration of the drug used for visualization, which is often not helped by intravenous injection of dye (e.g., indigo carmine), and we did not use this method. three cases were injected with methylene blue into the bladder through the catheter, and the catheter was removed to carefully observe the vaginal or urethral leakage without staining, excluding vesicovaginal fistula and urinary incontinence, which is also clear evidence of the presence of ureteral ectopic opening [6]. Case 2 repeated 3 ultrasound examinations finally pinpointed the location of the ectopic dysplastic kidney. Case 1 in which a high-dose intravenous urography could not be well visualized. Severe hydronephrosis was found in the affected kidney by ultrasound, and the diagnosis was clearly made by PCN under ultrasound guidance. Case 3 was diagnosed by vaginal compression angiography after high-dose intravenous urography. The use of this method in infants and children requires anesthesia and carries some risk, but accidents can be avoided if an experienced ultrasonographer is consulted. In our experience, diagnostic ultrasonography has a crucial role in the diagnosis of this disease, which is quite different from the conclusions of some authors [7]. In conclusion, sometimes the localization and diagnosis of ectopic ureteral opening is difficult and several examinations need to be combined to make an accurate judgment. Ultrasound can be used as the preferred noninvasive screening method, and further examination should be performed if there is dilated pelvis and calyces as well as images of dilated ureter or heavy kidney throughout, and IVU is the most basic means of examination. IV. Treatment The treatment of a single ureteral ectopic opening is determined by renal function. Due to the small size and poor function of the dysplastic kidney and the combined symptoms of urinary leakage, in principle, all dysplastic nephrectomy and ureterectomy should be performed [8], and surgical exploration is also the last means to confirm the diagnosis. All three cases in our group were cured by this procedure. The kidney and ureter involved in the ectopic opening of the ureter are abnormal in location, organization and function, and often have dilated ureter, sometimes with near-atretic ends. A single ectopic ureteral opening reveals a greater variability of lesions with more severe renal changes than a duplicated kidney with a duplicated ureter. It is unwise to keep the kidney and ureter with lesions unless necessary [3]. The decision to remove the entire ureter is inconclusive, and in boys with ectopic openings there is usually reflux and the entire ureter and kidney should be removed. three cases were performed with nephrectomy of the affected side without removing the entire ureter, which resulted in a small incision, short operative time, and less blow to the child. Bilateral single ureteral ectopic opening was very severe in the girl with severe dribbling incontinence. Treatment includes ureteral reimplantation and bladder neck reconstitution, sometimes with the option of colonic cystectomy to increase bladder capacity, and in recent years laparoscopic nephrectomy and ureterectomy has been applied, which is a promising treatment with little trauma and fast recovery [9]. In conclusion, as long as the preoperative localization and diagnosis of this disease are clear, the results are satisfactory regardless of whether nephrectomy or ureteral bladder reimplantation is chosen.