Antegrade (percutaneous) endopyelotomy

Initially reported by Ramsay and colleagues in 1984, the technique has several variations: cutting between two wires, cutting over a stent , invagination of the UPJ , and external incision of the UPJ through a transpelvic route . Cold knife, electrocautery, and laser have each been reported, with none conclusively demonstrated to be superior over the others. Antegrade endopyelotomy is particularly suitable in patients who have concomitant large-volume stone disease. Success rates with antegrade endopyelotomy range between 67% and 88% ( Table 1 ).

Antegrade (percutaneous) endopyelotomy

Initially reported by Ramsay and colleagues in 1984, the technique has several variations: cutting between two wires, cutting over a stent , invagination of the UPJ , and external incision of the UPJ through a transpelvic route . Cold knife, electrocautery, and laser have each been reported, with none conclusively demonstrated to be superior over the others. Antegrade endopyelotomy is particularly suitable in patients who have concomitant large-volume stone disease. Success rates with antegrade endopyelotomy range between 67% and 88% ( Table 1 ).

Ureteroscopic approach

Ureteroscopic retrograde endopyelotomy was initially reported by Inglis and Tolley in 1986. The most attractive feature of the ureteroscopic approach is the potentially reduced morbidity when compared with the percutaneous approach. The risk for subsequent ureteral stricture was historically higher with the use of large-diameter ureteroscopes and electrocautery . Whereas preemptive stenting was previously necessary to achieve passive ureteral dilatation, current small profile semirigid ureteroscopes and flexible ureteroscopes have practically abolished this need and significantly reduced ureteral complications with this procedure. The incision is performed using the holmium:yttrium-aluminum-garnet (YAG) laser at 10 W through a 200- to 365-μ laser fiber. Symptomatic and radiographic success range from 65% to 91% and from 73% to 85%, respectively . Geavlete and colleagues reported a success rate of 83.3% (18 months of follow-up) in 30 patients who had secondary UPJO (failed pyeloplasty [17 cases], failed endopyelotomy [13 cases]) ( Table 2 ).

Acucise endopyelotomy

Acucise endopyelotomy consists of a balloon electrocautery incision performed under fluoroscopic control and was first proposed by Chandhoke and colleagues in 1993. Drawbacks of cutting-wire endopyelotomy include difficulty in controlling the rate and depth of the incision and the risk for hemorrhage because of the lack of direct visual control. Bleeding complications have been reported in 3% to 10% of cases . Results from select series of cutting-wire balloon endopyelotomy are summarized in Table 3 .

El-Nahas and colleagues compared Acucise with ureteroscopic endopyelotomy in 40 patients who had UPJO in a prospective randomized trial (follow-up of 30 months). Exclusion criteria included the presence of crossing vessels, renal function less than 20%, or hydronephrosis of grade 3 or greater. Success rates were 85% for the ureteroscopic group and 65% for the Acucise group. There was no difference in the complication rate.

Preference of the surgeon, anatomic factors, and concomitant calculi are the main factors considered in the choice between the percutaneous and ureteroscopic approaches for endopyelotomy. The main advantage of percutaneous approaches is the ability to treat concomitant calculi. Body habitus or anatomic issues that may have previously limited retrograde access have decreased with modern ureteroscope technology, and decreased morbidity makes retrograde endopyelotomy an attractive option for the appropriate short-segment stricture.

Stenting after endopyelotomy

Stenting after endopyelotomy is still debated. No consensus exists regarding optimal stent size or duration of stenting. The assumption that a larger stent would result in a larger final caliber if healing occurs around the stent has been analyzed. Danuser and colleagues evaluated the influence of stent size in two consecutive series of patients who had UPJO managed by antegrade endopyelotomy. In group 1 (77 patients), a 14/8.2-French graduated stent was used. In group 2 (55 patients), a 27-French catheter was used for 3 weeks, followed by the same 14/8.2-French graduated stent for 3 weeks. The early success rates after 6 to 8 weeks in groups 1 and 2 were 83% and 94%, respectively. The long-term success rates after 2 years were 71% and 93%, respectively, suggesting that the benefit in the group with larger stents was durable. Similarly, Wolf and colleagues evaluated 69 patients undergoing 77 endoureterotomies for ureteral strictures and found that for strictures longer than 1 cm, use of a stent sized 12 French or greater seems to be beneficial.

Series of retrospectives nonrandomized studies did not support any benefits from using larger stents. Comparing 14/7-French versus 8-French stents after endopyelotomy, Kletscher and colleagues found no statistically significant difference. Hwang and colleagues evaluated 40 patients after percutaneous endopyelotomy, and the difference between 6-French and 14/7-French stents was not statistically significant.

What about duration of stenting? The classic study of Davis still drives the empiric 6-week stenting time. In contrast, Mandhani and colleagues compared 57 consecutive patients who had primary UPJO randomized to undergo 7/14-French internal endopyelotomy stent placement for 2 weeks (group 1) and 4 weeks (group 2), and no difference was found in drainage pattern stent-related symptoms, suggesting that 6 weeks may not be required. Properly conducted studies are required to establish evidence-based guidelines for stenting practice after endopyelotomy.

Endopyelotomy for secondary ureteropelvic junction obstruction

Ng and colleagues evaluated 42 patients (mean follow-up of 47.7 months) who underwent management of failed primary intervention for UPJO. Secondary intervention included open operative repair (n = 20) or percutaneous (n = 11), ureteroscopic (n = 5), or retrograde cautery wire balloon endopyelotomy (n = 6). Long-term success rate of endoscopic treatment of secondary UPJO was 59.1% overall, including a 71.4% success rate after a failed open operative procedure and a 37.5% success rate after a failed endourologic procedure. Success of open operative salvage was 95% overall, including 94.1% after failed endourologic intervention and 100% after failed open operative intervention. In summary, endopyelotomy may be the optimal initial intervention after failed pyeloplasty but has a poor outcome after failed endopyelotomy.