Evaluation of renal function in patients with a main renal stone larger than 1 cm and perioperative renal functional change in minimally invasive renal stone surgery: a prospective, observational study

Objectives Currently, no standardized method is available to predict success rate after percutaneous nephrolithotomy. We devised and validated the Seoul National University Renal Stone Complexity (S-ReSC) scoring system for predicting the stone-free rate after single-tract percutaneous nephrolithotomy (sPCNL). Patients and Methods The data of 155 consecutive patients who underwent sPCNL were retrospectively analyzed. Preoperative computed tomography images were reviewed. The S-ReSC score was assigned from 1 to 9 based on the number of sites involved in the renal pelvis (#1), superior and inferior major calyceal groups (#2–3), and anterior and posterior minor calyceal groups of the superior (#4–5), middle (#6–7), and inferior calyx (#8–9). The inter- and intra-observer agreements were accessed using the weighted kappa (κ). The stone-free rate and complication rate were evaluated according to the S-ReSC score. The predictive accuracy of the S-ReSC score was assessed using the area under the receiver operating characteristic curve (AUC). Results The overall SFR was 72.3%. The mean S-ReSC score was 3.15±2.1. The weighted kappas for the inter- and intra-observer agreements were 0.832 and 0.982, respectively. The SFRs in low (1 and 2), medium (3 and 4), and high (5 or higher) S-ReSC scores were 96.0%, 69.0%, and 28.9%, respectively (p<0.001). The predictive accuracy was very high (AUC 0.860). After adjusting for other variables, the S-ReSC score was still a significant predictor of the SFR by multiple logistic regression. The complication rates were increased to low (18.7%), medium (28.6%), and high (34.2%) (p = 0.166). Conclusions The S-ReSC scoring system is easy to use and reproducible. This score accurately predicts the stone-free rate after sPCNL. Furthermore, this score represents the complexity of surgery.

To evaluate the impact of pelvicaliceal anatomy on the success of retrograde intrarenal surgery (RIRS) for lower pole renal stones and determine which of these factors can be used to select patients who will benefit from RIRS. We evaluated 67 patients who underwent RIRS between 2009 and 2010 for isolated lower pole renal stones. The infundibular length (IL), infundibular width (IW), pelvicaliceal height (PCH), and infundibulopelvic angle (IPA) were measured by preoperative intravenous urogram. Success was defined as either complete clearance or clearance with insignificant residual fragments≤3 mm in size at 2-months follow-up. Mean IL was 26.7±7.9 and 28.2±5.3 mm, mean PCH was 20.7±6.6 and 23.2±4.9 mm in stone-free and non-stone-free patients, respectively. These were slightly larger in the non-stone-free group but not statistically significant (P=.140 and P=.072, respectively). Mean IW was 5.8±3.5 and 5.6±2.2 mm in stone-free and non-stone-free patients, respectively, which had no significant impact on the stone-free rate (P=.719). There were significant differences between the groups in terms of stone length (P=.001) and IPA (P=.003). The mean IPA was 49.37±11.83 and 37.61±13.22 mm in stone-free and non-stone-free patients, respectively. In addition to the influence of stone size, lower pole anatomy, especially IPA, has a significant impact on stone clearance for lower pole stones after RIRS. Copyright © 2012 Elsevier Inc. All rights reserved.

The aim of this study was to compare the outcomes of retrograde intrarenal surgery (RIRS) and miniaturized percutaneous nephrolithotomy (mini-PNL) in management of lower-pole renal stones with a diameter smaller than 15 mm. Between December 2009 and July 2012, the patients with the diagnosis of lower-pole stones were evaluated by ultrasonography, intravenous pyelography and computed tomography. The records of 73 evaluable patients who underwent mini-PNL (n = 37) or RIRS (n = 36) for lower-pole (LP) stones with diameter smaller than 15 mm were reviewed retrospectively. Of the 73 patients, 37 underwent mini-PNL and 36 underwent RIRS. The stone-free rates were 89.1 and 88.8 % for mini-PNL and RIRS groups, respectively. The mean operation time was 53.7 ± 14.5 in the mini-PNL group but 66.4 ± 15.8 in the RIRS group (P = 0.01). The mean fluoroscopy times and hospitalization times were significantly higher in the mini-PNL group. There was no major complication in any patient. RIRS and mini-PNL are safe and effective methods for treatment of LP calculi with a diameter smaller than 15 mm. RIRS is a non-invasive and feasible treatment option, and has also short hospitalization time, low morbidity and complication rate. It may be an alternative of mini-PNL in the treatment LP calculi with smaller than 15 mm.