Robot-assisted pyeloplasty for pelvi-ureteric junction obstruction of lower moiety in partial duplex system: A technical challenge.

Management of pelvi-ureteric junction obstruction (PUJO) in a duplex system is technically challenging as dissection at the pelvis may jeopardize the vascularity of the normal moiety ureter. Anastomosing the pelvis to the one single ureter will have a risk of future development of stricture which then will risk both the moieties. Robotic assistance enables appropriate tissue dissection; minimal handling of normal ureter and precision in suturing, overcoming the potential challenges involved in the minimally invasive management of such complex cases. We report the feasibility and efficacy of robot-assisted laparoscopic pyeloplasty in such case.

INTRODUCTION

Pelvi-ureteric junction obstruction (PUJO) in duplex system commonly involves the lower moiety and is an unusual entity and infrequently reported. Duplex system can be complete or partial variety with bifid system. Managing PUJO in partial duplex system is difficult for treating surgeon and technically challenging. We report the first case of partial duplex system with lower moiety PUJO managed with robot-assisted pyeloplasty.

CASE REPORT

A 28-year-old female presented with dull aching right flank pain of 6 months duration. An ultrasound scan revealed hydronephrotic right kidney. Intravenous pyelography (IVP) showed right partial duplex system with upper calyx as upper moiety and mid/lower calyx as a lower moiety. Furthermore, PUJO was apparent in the lower moiety of the two systems [Figure 1a]. Renal scan (Tc-99m DTPA) revealed 47% split function with preserved cortical function and obstructed drainage at PUJ in the right kidney. Retrograde pyelography was done before surgery to assess the length of lower moiety ureter to plan the surgical technique during reconstructive surgery which showed partial duplex system with lower moiety PUJO and very short lower moiety ureter [Figure 1b]. Port placements were similar to standard robot-assisted pyeloplasty with using three robotic arms and an additional 5 mm port for liver retraction. Toldt line was incised, and ascending colon and hepatic flexure were mobilized medially. The Gerota's fascia was incised longitudinally, and psoas muscle was identified. The ureter was identified by peristaltic movements and traced till PUJ. Renal pelvis was dissected, and duplex system was identified [Figure 2a]. The pelvis of the lower moiety was dilated with narrowing at the PUJ and a short nondilated ureter joining upper moiety ureter. The upper moiety ureter was draping anterior to the lower moiety dilated pelvis. The renal pelvis of the lower moiety was incised from lateral to medial aspect and extended beyond the PUJ into the common ureter [Figure 2b]. The narrowed PUJ segment of the lower moiety was excised, and the common ureter was spatulated over its lateral aspect. To avoid narrowing of the upper moiety, the upper end of spatulation was extended into the upper moiety ureter. End to side anastomosis was performed with continuous 4-0 vicryl sutures and double-J stent (DJS) placed across the anastomosis in upper moiety [Figure 2c and d], postoperative course was uneventful. Per urethral catheter was removed on day 1 of surgery and drain was removed on day 2. DJS was removed at 6 weeks. On Follow-up, the patient is pain-free and renal scan showed 48% split renal function in the right kidney with preserved cortical function and slow unobstructed drainage.

Figure 1

(a) Intravenous pyelography showing right partial duplex system with lower moiety pelvi-ureteric junction obstruction. (b) Retrograde pyelogram shows duplex system with upper calyx as upper moiety and mid/lower calyx as lower moiety with jet sign in lower moiety pelvi-ureteric junction

Figure 2

(a) Intraoperative image showing the dissected renal pelvis with partial duplex system (black arrow: Lower moiety pelvi-ureteric junction obstruction, red arrow: Upper moiety ureter). (b) Spatulated common ureter and upper moiety ureter (black arrow: Opened pelvi-ureteric junction obstruction, red arrow: Spatulation extending into upper moiety ureter). (c) Posterior layer reconstruction. (d) Double-J stent placement across the anastomosis into the upper moiety

DISCUSSION

Duplex system is a common anomaly of genitourinary tract. The lower pole PUJO was first described by Freyer and Deming in 1942.[1] Hydronephrosis of the lower segment is most often a result of vesicoureteral reflux (VUR). Obstruction at the level of the PUJ in duplex kidneys is rare. It is difficult to determine the true incidence, but it seems to be much less frequent than VUR, incidence being 2–3%.[2] Anatomically, the lower segment is the analog of a single renal system with usually about two-thirds of the parenchyma and at least two calyces and a true renal pelvis. That might explain the predilection of PUJO for the lower moiety. However, it has become apparent that the proximal ureter of an upper moiety can also be obstructed.[34] The clinical presentation of these patients is similar to that in single-system PUJO. To decide the best surgical approach, careful radiological evaluation of the obstructed duplex system is essential. IVP or computed tomography urography is preferred for anatomical and diagnostic purpose. A diuretic renogram scan provides information on renal function and the degree of obstruction. Ossandon et al. recommended cystoscopy and retrograde pyelography to exclude obstruction at other locations and to clarify the anatomy in duplex system.[5] The management follows similar guidelines as for single system PUJO with intention to improve drainage with widely patent dependent anastomosis. However, special care needs to be taken to preserve the vascularity of the upper moiety ureter and to avoid stenosis in the upper moiety system. This makes laparoscopic intervention in duplex systems technically challenging and requires expertise for intracorporeal suturing. Furthermore, preservation of the upper moiety ureter further adds to complexity. Metzelder et al. have reported two cases of PUJO in a lower moiety of complete duplex system managed by laparoscopic pyeloplasty.[6] Sahai et al. reported feasibility of laparoscopic pyeloplasty and pyelopyelostomy in a 41-year-old male patient with symptomatic PUJO in upper moiety of partial duplex system. The upper moiety was transected, and an incision was made over the ureteropelvic junction obstruction in the lower moiety. Total operative time was 210 min to complete the pyelopyelostomy and pyeloplasty.[7] Robotic assistance is particularly helpful in such complex cases because of its dexterity, better visualization, and faster and precise intracorporeal suturing. Our case demonstrates the feasibility and efficiency of robotic assistance in managing such complex PUJO.

CONCLUSION

Duplex system with lower moiety PUJO is a rare entity and technically challenging for reconstruction. Robot-assisted reconstruction in the duplex system is safe and feasible.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.