Successful percutaneous flexible ureteroscopy for treatment of distal ureteral stones under modified Valdivia position after Cohen reimplantation.

INTRODUCTION: Endoscopic retrograde access to the upper urinary tract after Cohen reimplantation for the treatment of vesicoureteral reflux in children is usually difficult. CASE
PRESENTATION: We experienced a case involving a few large ureteral stones in the right distal ureter after Cohen reimplantation. We initially failed retrograde access using flexible cystoscope. Therefore, we performed antegrade flexible ureteroscopy through the 10- to 12-Fr access sheath from the middle calyx to treat the few ureteral stones (>1.5 cm) in the right ureter with the patient in the modified Valdivia position. This one-stage procedure was successful. The patient achieved a stone-free status without major complications.
CONCLUSION: The herein-described approach that was implemented after Cohen reimplantation was successful. We believe that recent endourologic developments contributed to the good outcome in this case.

computed tomography

flexible ureteroscope

Hounsfield units

kidney, ureter, and bladder

ureteral access sheath

vesicoureteral reflux

Antegrade flexible ureteroscopy after Cohen reimplantation is impressive access and procedure to acquire stone‐free status.

Introduction

Cohen reimplantation is a cross‐trigonal technique first described by Cohen in 1975 for the treatment of children with VUR. The ureter is tunneled cross‐trigonally within the posterior wall of the bladder to exit in the contralateral bladder1. Therefore, if a patient requires a diagnostic or therapeutic approach to the upper urinary tract for urolithiasis at an older age, treatment of urothelial cancer, or treatment of ureteral stenosis, it is not easy to access the involved lesion site in the upper urinary tract.

The present report describes a patient who developed a few large stones in the right distal ureter after having undergone Cohen reimplantation for VUR 23 years previously. First, we performed percutaneous antegrade flexible ureteroscopy with access sheath for the right distal ureteral stones with the patient in the modified Valdivia position.

Case presentation

We experienced a case involving a young woman with a few large ureteral stones in the right distal ureter. The patient was 29 years old (height, 160.5 cm; weight, 49.9 kg; body mass index, 19.4 kg/m2) and had a medical history of bilateral Cohen reimplantation for VUR at 6 years of age. She visited to our hospital because of a 1‐month history of a frequently occurring high fever. Imaging studies including KUB radiography, intravenous pyelography, and CT revealed a few large ureteral stones measuring 1.5 × 1.2 cm (992 HU), 1.5 × 1.2 cm (1072 HU), and 1.4 × 1.3 cm (1008 HU) with mild hydronephrosis in the right distal ureter (Fig. 1). We might discuss the difficulty of the retrograde ureteral approach because of the patient's history of a bilateral cross‐trigonal procedure. Therefore, we initially planned to carry out the percutaneous antegrade approach using flexible ureteroscopy for treatment of the right distal ureteral stones if we were unable to retrogradely insert a guide wire to the ureteral orifice using a flexible cystoscope.

Figure 1

Intravenous pyelography (a), (b), and CT radiography at pre‐operation (c). The arrow and circle reveal right ureteral stones in distal ureter after Cohen procedure for VUR 23 years ago. The dotted arrow indicates a right hydroureter.

First, we treated the distal ureteral stones with the patient in the modified Valdivia position under general anesthesia. As we expected, the initial attempt to localize the right ureteric orifice by cystoscopy failed because of severe edema of the ureteral orifice and the difficult angle for guide wire insertion. Therefore, we percutaneously punctured the middle renal calyx. A guide wire was passed down the right ureter, but it did not pass through the stones and advance into the bladder. We then inserted a 10‐ to 12‐Fr UAS (UROPASS; Olympus, Tokyo, Japan) to the distal ureter over the guide wire. We advanced a reusable fURS (URF‐P6; Olympus) through the UAS to access the target stones (Fig. 2). After reaching the stones, we disintegrated them using a holmium laser (VersaPulse PowerSuite 120; Lumenis, Dreieich, Germany) with the dusting effect (0.3–0.5 J, 20–40 Hz) and then retrieved as many stone fragments as possible. Finally, the guide wire was passed into the bladder. A 6‐Fr ureteral stent into right ureter and 10‐Fr nephrostomy tube in right kidney were then antegradely placed. The operative time was 123 min. Although the patient had no postoperative complications, we found that the reusable fURS was damaged. The minor leak in working channel from the tip of fURS was found during reprocessing of scope after procedure.

Figure 2

Fluoroscopic image obtained during antegrade fURS access for the right ureteral stones. (a) The arrow shows the 10‐ to 12‐Fr access sheath in the right ureter. (b) The dotted arrow and circle indicate the fURS and ureteral stones, respectively.

The patient had stone‐free status on KUB in postoperative day 1 (Fig. 3). The patient was discharged on postoperative day 4. The stone components were 97% calcium phosphate and 3% calcium oxalate.

Figure 3

Kidney, ureter, and bladder radiography on postoperative day 1.

Discussion

In the present case, we successfully performed percutaneous antegrade flexible ureteroscopy with access sheath for treatment of distal ureteral stones with the patient in the modified Valdivia position after bilateral Cohen reimplantation.

The incidence of urolithiasis after ureteroneocystostomy in childhood is rare at 0.06%. The incidence of urolithiasis after Cohen reimplantation is even more uncommon at 0.02%.2 As this population gets older, they will be an age group at higher risk for stone formation. Achieving ureteric access for treatment is not easy when a patient with a history of Cohen reimplantation has symptoms due to upper urinary tract stones. Some investigators had some challenges of retrograde approach for patients postoperative Cohen reimplantation like inserting a catheter through a supra‐pubic tract under cystoscopic vision, using a curved‐tip angiographic catheter or cobra head catheter under cystoscopic guidance (Table 1). Conversely, percutaneous antegrade approach for such a patient was limited. We selected the percutaneous antegrade approach using a fURS with UAS for the distal ureteral stones in this case because of failed retrograde insertion of the guide wire to the ureteric orifice by using flexible cystoscope. To the best of our knowledge, only seven reported cases, including the present case, have utilized the percutaneous antegrade approach after Cohen reimplantation. However, the case used a fURS with UAS antegradely for treatment of distal ureteral stones under modified Valdivia position is only our case. This technique due to recent endourological developments is easy to access to the target stones. On the other hand, antegrade flexible access through percutaneous tract is so tough because of steep angle between each renal calyx and ureter, especially lower pole and ureter. Therefore, the surgeon needs complicated manipulation of flexible ureteroscopy compared with usual retrograde access even if expert in endourology. Especially, it is one of the most difficult approaches in complicated anatomical case like postoperative Cohen reimplantation. Consequently, the flexible ureteroscopy may be easily damaged. In present case, we had the minor leak in working channel from the tip of fURS after procedure. We wonder if that is why the resistance for reusable fURS often occurred due to much steep angle when the scope is inserted from tip of access sheath to distal ureter. And then, we inserted laser fiber into working channel with slight deflection. Therefore, we will recommend single‐use ureteroscopy will be better choice and management option in complicated case like this patient. If we could pass the stiffness guide wire into bladder through the target stones antegradely in present case, we think that it may be possible to approach retrogradely using semi‐rigid ureteroscope because the ureter become straight. Anyway, we succeeded percutaneous flexible ureteroscopy through the UAS with safety for treatment of distal ureteral stones under modified Valdivia position after Cohen reimplantation.

Table 1

Summary of previous methods to access upper urinary tract after Cohen reimplantation

	Approach	Patients (n)	Specification of technique
De Castro4	Retrograde	1	Supra‐pubic needle inserted opposite the ureter under endoscopic vision
Lamesh5	Retrograde	5	Trocar was inserted from transverse supra‐pubic and then ureteral catheter was inserted into the ureter endoscopically
Argueso6	Retrograde	1	Retrogradely inserted guide wire under cystoscopic guidance with 5‐Fr cobra head catheter
Santarosa7	Retrograde	1	Supra‐pubic puncture was done and then guide wire was inserted endoscopically
Wallis8	Retrograde	6	Retrogradely Inserted guide wire under cystoscopic guidance with curved tip vascular access catheter and angle‐tipped glide wire
De Castro9	Retrograde	13	Supra‐pubic retrograde ureteral catheterization under cystoscopic guidance
Lusuardi10	Retrograde	8	Retrogradely inserted Tiemann ureteral catheter under cystoscopic guidance. And then fURS is passed to the stone
Khalil11	Retrograde	1	Retrogradely inserted curved guide wire into the ureteral orifice and then inserted URS
Adam3	Retrograde	1	Supra‐pubic puncture was done and guide wire was inserted under cystoscope with grasping forceps
Emiliani12	Retrograde	3	7‐Fr angled orifice catheter and angled stiff wire is used for first access. Placed 10‐/12‐Fr UAS and used single‐use fURS
Rich13	Antegrade	1	Antegradely inserted guide wire into the bladder and dilated distal ureter
Chaudhary1	Antegrade	1	Antegradely inserted guide wire and placed ureteral stent, and then retrograde transurethral URS was done at 4 weeks later
Krambeck2	Antegrade	4	Antegradely inserted guide wire and then performed three percutaneous nephrolithotomy, one placement of ureteral stent
Our case	Antegrade	1	Antegradely inserted 10‐12 Fr UAS through middle calyx to distal ureteral and then, fURS was inserted through UAS

Conclusion

We experienced a case involving some large stones >1.5 cm in the right distal ureter after Cohen reimplantation in childhood. We successfully performed percutaneous antegrade flexible ureteroscopy with ureteral access sheath for treatment of the distal ureteral stones with the patient in the modified Valdivia position. We believe that recent endourologic developments contributed to the good outcome in this case.

Conflict of interest

The authors declare no conflict of interest.