STONE DISEASE

Third prize: contemporary percutaneous nephrolithotripsy: 1585 procedures in 1338 consecutive patients
Duvdevani M, Razvi H, Sofer M, Beiko DT, Nott L, Chew BH, Denstedt JD
Division of Urology, The University of Western Ontario, London, Ontario, Canada
J Endourol. 2007; 21: 824-9

• Background and Purpose: The approach to urinary-stone disease has changed dramatically over the last three decades with a transition from open surgery to minimally invasive procedures. Percutaneous nephrolithotripsy (PCNL) is a cornerstone of the treatment of kidney and selected upper-ureteral stones and continues to evolve with advances in techniques and instrumentation. The purpose of this study was to assess outcomes and trends prospectively in a large contemporary group of patients undergoing PCNL.
• Patients and Methods: Between July 1990 and December 2005, all 1338 patients at a single center scheduled for PCNL (N = 1585 procedures) were enrolled. Their mean age was 53 years (range 4-89 years). Data including comorbidities, stone burden, stone location, surgical time, hospital length of stay, rate of secondary procedures, and adverse events were collected prospectively. The primary outcome measures were stone-free rate and complications.
• Results: There was a substantial incidence of comorbid medical conditions (48.8%) and anatomic renal abnormalities (25.3%), demonstrating the diverse and challenging patient population in this contemporary series. The overall stone-free rate at 3 to 6 months of follow-up was 94.8%.
• Conclusions: Percutaneous nephrolithotripsy is a highly effective procedure and may be performed in a diverse group of patients with comorbid conditions and renal abnormalities. Improved intracorporeal lithotripters, balloon dilation of the tract, use of flexible instruments, and liberal use of secondary nephroscopy result in excellent stone-free rates with low morbidity.
  
  
• Editorial Comment
  This large contemporary series provides important information that is helpful with regards to counseling patients on the risk:benefit ratio of percutaneous nephrolithotomy (PCNL). It is important to emphasize that these results are from a very experienced tertiary center with a large volume of procedures (over 100 PCNL’s per year), and one might expect that success rates may be somewhat lower and complication rates somewhat higher at sites with lower surgical volumes.
  The broad applicability of the PCNL is supported by the wide age range treated (4-89), the substantial comorbidity (in 49% of patients) and the significant proportion of patients with renal abnormalities (25%). In spite of this challenging patient population, the success rate of 90% at time of discharge is commendable. We should note that no computerized tomography was utilized for postoperative follow-up – recent studies would suggest that more sensitive CT scans would detect residual stones in approximately 20% of those deemed stone-free by traditional imaging.
  Importantly, the high success rate in this series was obtained without the need for routine upper pole access as has been recommended by other investigators. It may have been useful to stratify efficacy and safety based on the presence of renal anomalies and patient comorbidites or based on the need for multiple or supracostal access.
  The authors report that they converted from a serial Amplatz dilator system to a balloon dilation system in 1995, following reports by other investigators of decrease in bleeding with this approach. It would have been interesting to know if their 7% bleeding complication rate (minor and major) decreased after the switch to balloon dilation. The low rates of pulmonary complications and major bleeding set new standards for preoperative counseling of patients.

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