Endopyelotomy still has an important role in the management of ureteropelvic junction obstruction

Advances in endourology have lead to a change in the management of primary ureteropelvic junction obstruction (UPJO) over the past 25 years. Minimally invasive procedures (endopyelotomy and laparoscopic pyeloplasty) have replaced open pyeloplasty as the standard of care. The benefits of these procedures include less postoperative pain, shorter hospital stay, faster return to normal activities and less morbidity.^1–3

Laparoscopic pyeloplasty produces success rates (90% to 100%) equivalent to open pyeloplasty and has a 10% to 15% higher success rate when compared to endopyelotomy (antegrade or retrograde).^4–6 For these reasons, many urologists consider laparoscopic pyeloplasty the treatment of choice for primary UPJO; however, the technical challenges associated with laparoscopy and intracorporeal suturing have limited its widespread use. Therefore, although laparoscopic pyeloplasty has become the new standard of care, endopyelotomy remains an effective alternative first-line treatment for certain patients with primary UPJO, and can be easily performed by most urologists without the need for advanced laparoscopic training. Additionally, it is the treatment of choice for failed open or laparoscopic pyeloplasty and concomitant renal calculi. We present the case that endopyelotomy still has a role in the management of UPJO in select patients.

Background

Antegrade endopyelotomy was first described in 1984 by Ramsay and colleagues⁷ and the retrograde technique was then reported in 1986 by Inglis and colleagues.⁸ The choice of approach (antegrade or retrograde) has typically been influenced by the need to treat concomitant calculi, surgeon preference and anatomic factors. Endopyelotomy is based on the principle of the Davis intubated ureterotomy, where a full thickness incision through a strictured segment of ureter will heal over a stent to a larger caliber in a period of weeks.⁹ A number of different cutting tools have been described including cold knife, electrocautery and laser. Acucise (Applied Medical, Rancho Santa Margarita, CA) was introduced in 1993 and consists of an electrocautery cutting wire over a dilation balloon.¹⁰ Used primarily in a retrograde fashion, the device was designed so it could be used without proficiency in ureteroscopy. However, most studies comparing Acucise with other forms of endopyelotomy have shown lower success rates for Acucise.^11,12

Success rates

Several factors influence success rates for endopyelotomy, including the presence of a crossing vessel (somewhat controversial), length of narrowing, preoperative split renal function, degree of hydronephrosis and the presence of contrast extravasation at the time of surgery. Improvements in fibre optic technology have lead to better visualization with ureteroscopy, which has contributed to higher success rates with the retrograde approach. Stilling and colleagues performed retrograde endopyelotomy with a 89% success rate in carefully selected patients (i.e., patients without a very large pelvis, high ureteral insertion, renal split function <20% or a long narrowed segment of UPJ (>2 cm).¹³ For patients with these risk factors, Stilling and colleagues, as we do, recommend laparoscopic pyeloplasty. A study by Van Cangh and colleagues found that the presence of a crossing vessel lead to a lower success rate with endopyelotomy compared to the absence of a crossing vessel (42% vs. 86%).¹⁴ Similarly, Parkin and colleagues found a lower success rate in 11 of 24 patients who had crossing vessels and were treated with retrograde laser endopyelotomy (55% vs. 85%).¹⁵ However, Gupta and colleagues looked at 400 patients and found that only a small percentage of endopyelotomy failures had a crossing vessel (<5%).¹⁶ Kapoor and colleagues found a lower success rate (62% vs. 90%) for patients with poor renal function (glomerular filtration rate [GFR] = 5–15 mL/min) who underwent antegrade endopyelotomy, as compared to patients with better renal function (GFR >15 mL/min).¹⁷ Several other studies support this conclusion,^16,18 and preoperative differential renal function <30% is associated with a worse prognosis. Biyani and colleagues found a lower success rate with Acucise endopyelotomy when no contrast extravasation was seen (25% vs. 48%), highlighting the importance of a full thickness incision to periureteral fat.¹⁸ Finally, the degree of hydronephrosis has been shown to have an effect on success rates with endopyelotomy: patients with mild to moderate hydronephrosis have higher success rates compared to those with severe hydronephrosis.^19,20 Presumably, reduction of the renal pelvis during pyeloplasty assists in drainage of the kidney—something that cannot be performed during endopyelotomy.

The overall success rates for patients treated with endopyelotomy are lower than those treated with laparoscopic pyeloplasty. In a highly selective patient population, however, endopyelotomy can produce success rates that are equivalent to laparoscopic pyeloplasty. Patients without any adverse features (differential split renal function <30%, moderate-severe hydronephrosis, crossing vessel, UPJO >2 cm stenosed segment) enjoy success rates after endopyelotomy (80%–93%) that are comparable to laparoscopic pyeloplasty (90%–100%).^4,5,11

A recent study revealed that endopyelotomy is more cost-effective, has shorter operating times and has lower equipment costs.²¹ For these reasons, endopyelotomy can still be a useful first-line cost-effective treatment in carefully selected patients, and is not associated with a steep learning curve or a requirement for advanced laparoscopic training. As a result, endopyelotomy can be performed by a larger number of urologists which eliminates the need for many patients to travel to other centres to be treated by laparoscopy-trained urologists. This has the potential for significant cost savings, both to the patient and the health care system.

Patients who fail primary endopyelotomy can be managed laparoscopically with excellent outcomes. Prior endopyelotomy is not a contraindication to subsequent laparoscopic pyeloplasty, and salvage laparoscopic pyelopasty produces comparable success rates to laparoscopic pyeloplasty performed initially (94%).²² Finally, it has been shown that endopyelotomy is the most effective treatment for salvaging failed laparoscopic or open pyeloplasty.²³ In this study, 10 of 227 patients had a failed laparoscopic pyeloplasty. Seven patients underwent salvage endopyelotomy using laser (n = 3), cold knife (n = 2) and cutting balloon endopyelotomy (n = 2). For 1 of these patients, the laser endopyelotomies failed; the remaining patients experienced improved imaging and symptom relief.

Conclusion

While pyeloplasty is the gold standard for surgical treatment of primary UPJO, endopyelotomy is still a useful alternative first-line treatment option for highly selective patients. The presence of a crossing vessel, preoperative differential split renal function <30%, UPJO >2 cm and moderate to severe hydronephrosis are associated with a poorer prognosis for patients treated with primary endopyelotomy, and these patients should be offered laparoscopic pyeloplasty as first-line treatment. However, for patients without any of these adverse features, endopyelotomy is a reasonable first-line treatment option with acceptable outcomes, and can be performed by a larger number of urologists without the need for subspecialty laparoscopic training. Endopyelotomy is also a less invasive procedure, associated with a shorter operative time and can be a reasonable treatment option for patients with significant medical comorbidities or contraindications to laparoscopic surgery. Finally, endopyelotomy is the treatment of choice for failed pyeloplasty and concomitant renal calculi.