Incidental Finding of Unilateral Complete Duplication of Ureter in a Patient with Large Ureteric Calculus Obstructing Both Left Limbs

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INTRODUCTION
Duplication of the ureter is one of the most common congenital malformations of the urinary tract. A kidney with two pyelocaliceal systems is accompanied by either a single or two partially (or completely) separate ureters inserting into the bladder. [1] Nation et al. reported ureter duplications of any form in 0.9% of the general population in a series of autopsies. The prevalence of this condition is higher for female population and is often bilateral. [2] Its incidence rate ranges from 0.7% to 4% and presents on 0.3% of excretory urograms. [3,4] In complete duplication, the ureter to the upper segment arises from a cephalad position on the mesonephric duct and consequently, it remains attached to the mesonephric duct longer. As a result, it migrates farther, ending median and inferior to the ureter which drains the lower segment. (Weigert-Meyer law) Thus, the upper segment ureter may become ectopic and obstructed, whereas the lower segment ureter may end laterally and have a short intravesical tunnel leading to vesicoureteral reflux. [5] Ureteral duplication is often asymptomatic but may be associated with recurrent urinary tract infections, urolithiasis, and congenital problems such as ectopic and obstructed ureter, often combined with a ureterocele and vesicoureteral reflux. Urolithiasis is precipitated by the relative stasis of urine in such patients but other factors unrelated to the duplication also cumulate to this pathology. [6] Hereby, we present a rare case of a patient with obstructive ureteric urolithiasis secondary to undiagnosed complete ureteral duplication. The large calculus in the vesicoureteral junction was obstructing both duplicated ureters. The aim of this study was to discuss the challenges arising from this clinical entity and the possible diagnostic approaches for those patients.  (Figs 1-3). The patient underwent a rigid cystoscopy, which revealed the presence of two separate left orifices and a large stone of the vesicoureteral junction causing obstruction in both orifices. A diffuse inflammation was present in the area of trigone. We managed to insert a safety wire in the upper left orifice up to the   renal pelvis and a double J ureteral stent (4.8 Fr, 28 cm) was placed. During her treatment in our Clinic, parenteral antibiotics were administered along with adjunctive measures and her fever resolved. Both her renal function tests and her general condition improved, and she was discharged and rescheduled for ureteroscopy (URS).

CASE REPORT
Thus, the patient was re-admitted two weeks post discharge and after all necessary pre-operative examinations, she underwent a rigid laser lithotripsy under general anesthesia and antibiotic prophylaxis. The large calculus was visually pulverized using our clinic's holmium laser, while the remaining large fragments were extracted with the use of a basket. Finally, the lower left ureter was restented with a double-J stent. (4.8 Fr,26 cm). Intraoperatively, C-arm radiographics confirmed the proper stenting of both duplicated left ureters (Fig. 4) and a plain KUB film revealed a stone free patient (Fig. 5). Postoperative period was uneventful, and the patient was discharged from the hospital on postoperative day 2, after removing the Foley catheter. Six weeks after surgery, patient underwent a KUB X-ray in order to be evaluated and to confirm that she was stone free and afterwards a cystoscopy was performed for the double-j removal. Both orifices of the duplicated ureters remained inflammatory (Fig. 6).

DISCUSSION
Although some patients with duplicated ureter (complete or incomplete) are asymptomatic, they usually present with persistent or recurrent UTIs. Moreover, an ectopic ureter of the upper pole secondarily to this congenital malformation is not uncommon. The presence of vesicoureteral reflux and ureterocele are reported as well and confirmed by voiding cystourethrogram. Kirby et al., also reported a patient with urinary retention secondary to ureteral calculus in a duplicated system. [7] Large ureteral calculi in a completely duplicated ureter are a challenging clinical entity for the clinician but not new to the urologists. Thus, large calculi in the vesicoureteral junction can be obstructing both ureters in completely duplicated ureters. In 1959, Sidoti et al. was the first to report large ureteral calculi in a completely duplicated ureter. [8] Unfortunately, the problem in the past was that the patient had to undergo a major operation due to lasers unavailability. We searched through the databases of PubMed,   Scopus, and Google Scholar and to the best of our knowledge this is the fourth case of patient with complete ureteral duplication concomitant with calculi obstruction of both limbs. [6,9,10] This occurrence may hinder the stenting of the obstructed orifices which are often inflammatory. In such complicated cases combined with suspected pyelonephritis or severe hydronephrosis, the option of an urgent lithotripsy should be considered. Nevertheless, severe sepsis might be an independent prognostic factor of action and therefore should be considered as well. In our case after discussion with the patient, we opted for URS laser lithotripsy as we considered this approach both less invasive and more effective for the patient. Depending on the location and the composition of the stone in obstructed duplicated ureters Bhatia et al., in 1993 highlighted the role of extracorporeal shockwave lithotripsy in duplex system lithiasis. [11] In recent years, prenatal ultrasonography has led to the early diagnosis in many asymptomatic neonates. Neglected cases like the one reported above, lead to complicated and often life-threatening pathologies. This highlights the value of prenatal ultrasonography and the need for its catholic application. Asymptomatic and undiagnosed patients with completely duplicated ureters are prone to severe complications like secondary obstructing ureteric or vesical lithiasis and complicated UTIs or chronic urothelial inflammation. Early diagnosis in these patients is an imperative need and the screening protocols should always be applied. Our case demonstrates that in patients with distal ureter lithiasis and concomitant completely duplicated ureters the stenting of either of the two ureters may be tricky and not always feasible. In such cases, alternative options should be considered.

Author contributions
I.T. conceptualized the report and wrote the paper. D.C. collected the data and images. K.G. and D.K. provided insightful comments and expert advice. K.S. helped to write the manuscript and approved the final variant. All authors have read and approved the submitted version of the manuscript.

Funding
The authors have no funding to declare.