Introduction

Pyeloplasty has traditionally been considered the gold standard technique for surgical treatment of ureteropelvic junction obstruction (UPJO). The most common pyeloplasty technique utilized in the primary repair setting is dismembered pyeloplasty, which has been associated with success rates of up to 97% in the adult population.¹ Laparoscopic and robotic pyeloplasty have established equivalence to the gold standard of open pyeloplasty in treating UPJO, with the added benefits of smaller incisions, less pain and convalescence.² However, failed pyeloplasty has remained a challenging problem as secondary repair is often complicated by peripelvic scarring and obliteration of normal dissection planes. Traditional treatment options include endoscopic techniques, ureterocalicostomy or secondary pyeloplasty. Secondary repair is complicated, and thus there is no clearcut management paradigm for recurrent UPJO after prior failed intervention.

Endoscopic Techniques

Endoscopic techniques, including endopyelotomy and balloon dilation, have been historically valued for their low morbidity profile, but these approaches have limited success rates ranging from 20%–70% in the redo setting.^3,4 Evidence suggests that it is inferior to a reoperative approach, especially as a secondary treatment modality.⁵

Ureterocalicostomy

Ureterocalicostomy is generally reserved for patients with a recurrent UPJO associated with an inaccessible, completely intrarenal pelvis. The reported success rates among adult populations range from 60%–75% in this setting.⁶ However, given the higher technical demands associated with ureterocalicostomy and the added morbidity with having to resect the lower pole of the kidney, the literature supporting the use of ureterocalicostomy is limited to small case series.

Revisional Pyeloplasty

The challenges involved with revisional pyeloplasty are related to the basic tenets of reconstructive surgery: mucosa-to-mucosa approximation, preservation of the blood supply and a tensionless repair. Fibrosis and scarring surrounding the ureteropelvic junction, as well as the risk of further disruption to the already fragile ureteral blood supply, can add to the complexity of these cases. Traditional teaching describes the utilization of various renal pelvis flap options such as the spiral flap, vertical flap and Y-type flap for revisional pyeloplasty. Although most urology trainees are accustomed to the theoretical application of these flaps as seen in textbooks, the actual viability of these flaps is questionable, and success rates of these flaps are not well supported by the literature.

Despite the aforementioned challenges, secondary pyeloplasty has been described as a suitable option for definitive repair, with reported success rates of 83%–91%.^7,8 Although redo repair may be more difficult to perform as evidenced by its higher median estimated blood loss and longer median operative times, secondary pyeloplasty is associated with similar safety and efficacy when compared to primary pyeloplasty.⁹

Most studies report on the utilization of dismembered (transecting) pyeloplasty for management of recurrent UPJO. A transecting pyeloplasty is necessary in cases involving an obliterative UPJO or a UPJO secondary to a missed crossing vessel during primary pyeloplasty. However, due to the importance of preserving the ureteral blood supply in a reoperative field, nontransecting techniques may provide advantages in the secondary repair setting. Nontransecting pyeloplasty can avoid the need for an extensive ureterolysis and circumferential transection across the renal pelvis, which may be difficult to perform in the reoperative setting and can lead to excessive ureteral devascularization with impaired healing. Furthermore, nontransecting techniques may help facilitate a tension-free anastomosis since part of the ureter remains in continuity. Traditionally described nontransecting techniques include the Fenger (Heineke-Mikulicz) and Y-V pyeloplasty, which solely involve making a longitudinal incision along the length of the stricture. These techniques, however, are typically limited to management of short-segment (≤1.5 cm) strictures and for high insertion UPJO in patients without a redundant renal pelvis.

In the last decade, the major developments in robotic ureteral reconstructive surgery have included the use of near-infrared fluorescence technology to assess real-time tissue perfusion, nontransecting techniques to preserve the ureteral blood supply and buccal mucosa tissue grafting.¹⁰ These concepts that were applied toward ureteral stricture disease were also well suited to address recurrent UPJO.

Similar to the aforementioned nontransecting techniques, robotic buccal mucosa grafting involves making a longitudinal incision along the anterior surface of the strictured UPJO rather than transection across the UPJO. A buccal mucosa graft is then harvested and anastomosed in an onlay fashion to the remaining defect. As such, this technique maintains the advantages of preserving the ureteral vasculature and offers the ability to manage longer and more complex strictures, which may not be possible with other nontransecting techniques. Multi-institutional data from CORRUS (Collaborative of Reconstructive Robotic Ureteral Surgery) have shown similar success rates in primary and secondary pyeloplasty when buccal mucosa grafting is an available option.⁹

Conclusion

Robotic pyeloplasty not only is a reliable option for management of primary UPJO, but also is an effective method for secondary repair of recurrent UPJO. Although previous thinking favored the utilization of endoscopic management in secondary repair due to the risks of surgery in a reoperative field, recent developments suggest that shifting the paradigm from transecting techniques and flaps to nontransecting techniques and tissue grafting may further improve outcomes for this challenging situation.

Disclosures

Daniel Eun is a consultant for Intuitive Surgical, Johnson and Johnson, Medtronic and Histiosonics; has ownership interest in Melzi Corp; and receives grant support from Hitachi Medical.