STONE DISEASE

Long-Term Outcome of Endopyelotomy for the Treatment of Ureteropelvic Junction Obstruction: How Long Should Patients be Followed Up?
Doo CK, Hong B, Park T, Park HK
Department of Urology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
J Endourol. 2007; 21: 158-61

• Purpose: To evaluate the long-term success rate of endopyelotomy for the treatment of ureteropelvic junction (UPJ) obstruction.
• Patients and Methods: Between January 1995 and December 2003, 85 endopyelotomies (10 percutaneous, 75 retrograde) were performed in 77 patients with a mean age of 35.2 +/- 13.9 years. The mean number of procedures per patient was 1.14, with 69 patients undergoing a single procedure. Endopyelotomies were performed using either a cold knife (N = 26), Ho:YAG laser (N = 47), or hook electrode (N = 12). Treatment success was defined as symptomatic relief with radiographic resolution or stabilization of renal function, as judged by an excretory urogram or diuretic renogram. Kaplan-Meier analysis was used to determine the long-term probability of success.
• Results: With a median follow-up of 37.3 months (range 3-98 months), the overall success rate was 67.5%, and the median time to failure was 7.7 months (range 1-50 months). Kaplan-Meier estimates of success were 87.8% at 6 months, 76.9% at 12 months, 72.2% at 18 months, 68.7% at 24 months, 64.8% at 36 months, and 61.6% at 60 months. The success rate was not significantly affected by the etiology, surgical approach, or incisional method. Similarly, the degree of preoperative hydronephrosis or renal function did not affect the success rate.
• Conclusions: The success rate of endopyelotomy decreases as the follow-up increases. Although most failures were detected within 1 year of the procedure, it appears that follow-up of at least 36 months is required for patients who have undergone endopyelotomy for UPJ obstruction.
  
  
• Editorial Comment
  This study lacks standardization in surgical technique. As the cutting modality and size and duration of stenting varied, it is difficult to make recommendations regarding best surgical practices. Yet this study does address a question that has eluded us to date. How long should endopyelotomies be followed?
  While the median time to failure was 8 months, only 7% of patients failed beyond 2 years. This suggests that one could focus postoperative imaging during the period when failure is most likely to occur. However, the authors do not report the presentation of the 7% of patients who failed beyond 2 years – were they symptomatic or silent obstruction? Answering this question is critical if one wishes to eliminate radiographic follow-up at 2 years postoperative.
  The authors report that the degree of hydronephrosis and preoperative renal function did not predict success with endopyelotomy. Indeed, the authors report a 60% success rate in kidneys with less than 25% function. This is in sharp contrast to the body of evidence that supports the use of these two variables in patient selection for endopyelotomy.

Dr. Manoj Monga
Professor, Department of Urology
University of Minnesota
Edina, Minnesota, USA