RESUMEN
BACKGROUND: Stone nomogram by Micali et al., able topredict treatment failure of shock-wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL) in the management of single 1-2 cm renal stones, was developed on 2605 patients and showed a high predictive accuracy, with an area under ROC curve of 0.793 at internal validation. The aim of the present study is to externally validate the model to assess whether it displayed a satisfactory predictive performance if applied to different populations. METHODS: External validation was retrospectively performed on 3025 patients who underwent an active stone treatment from December 2010 to June 2021 in 26 centers from four countries (Italy, USA, Spain, Argentina). Collected variables included: age, gender, previous renal surgery, preoperative urine culture, hydronephrosis, stone side, site, density, skin-to-stone distance. Treatment failure was the defined outcome (residual fragments >4 mm at three months CT-scan). RESULTS: Model discrimination in external validation datasets showed an area under ROC curve of 0.66 (95% 0.59-0.68) with adequate calibration. The retrospective fashion of the study and the lack of generalizability of the tool towards populations from Asia, Africa or Oceania represent limitations of the current analysis. CONCLUSIONS: According to the current findings, Micali's nomogram can be used for treatment prediction after SWL, RIRS and PNL; however, a lower discrimination performance than the one at internal validation should be acknowledged, reflecting geographical, temporal and domain limitation of external validation studies. Further prospective evaluation is required to refine and improve the nomogram findings and to validate its clinical value.
RESUMEN
PURPOSE: Prospective randomized trial to compare standard vs delayed approach to dorsal vascular complex (s-DVC vs d-DVC) in robot-assisted radical prostatectomy (RARP). METHODS: Patients scheduled for RARP were randomized into a 1:1 ratio to receive either s-DVC or d-DVC by two experienced surgeons. In s-DVC arm an eight-shaped single stitch was given at the beginning of the procedure and the DVC was subsequently cut at time of apical dissection; in d-DVC arm the plexus was transected at the end of prostatectomy, prior to apex dissection and then sutured. Primary endpoint was difference in estimated blood loss (EBL) and a sample size of 226 cases was calculated; ad interim analysis was planned after 2/3 of recruitment. RESULTS: Endpoint was reached at ad interim analysis after 162 cases (81 s-DVC, 81 d-DVC) and recruitment was, therefore, interrupted. Baseline and tumor characteristics were overlapping. EBL was significantly higher in d-DVC arm (mean EBL 107 vs 65 ml, p = 0.003), but without differences in post-operative hemoglobin, transfusions and complications. Overall PSM rate was higher in d-DVC arm (21.0 vs 14.8%, p = 0.323), with statistical significance relatively to organ-confined disease (15.5 vs 3.6%, p = 0.031). Apical involvement was instead significantly higher in s-DVC arm (prevalence in PSM patients 66.7 vs 23.5%, p = 0.020). Post-operative PSA, continence and potency rates were similar between groups. CONCLUSIONS: Standard and delayed approaches to DVC are safe and lead to similar functional outcomes. A delayed approach exposes to a higher risk of PSM in organ-confined disease but with a lower risk of apical involvement.