Objective: To examine and predicting stone-free rates (SFRs) after minimally invasive-percutaneous nephrolithotomy (mini-PNL) based on computed tomography (CT), instead of X-ray or ultrasound control. Patients and Methods: We identified 146 mini-PNL patients with pre- and postoperative CT scans. Patient and stone characteristics were assessed. Stone-free status was defined as ≤3 mm residual fragment after mini-PNL according to postsurgery CT scan. Multivariable logistic regression analyses predicted stone-free status after mini-PNL. Results: Overall, 62 (42.5%) patients achieved stone-free status after mini-PNL. In multivariable analyses, stone size was the only independent predictor for stone-free status (OR 0.9; p = 0.02). Patients with stones > 20 mm were less likely to achieve stone-free status, than those harboring stones 10–20 mm (OR 0.3; p = 0.009). SFRs according to stone size categories (< 10, 10–20, and > 20 mm) were 33.3, 50.5, and 25%. Body mass index (BMI) and stone density (Houndsfield units) were no independent predictors for stone-free status after mini-PNL. Conclusions: We report lower SFRs than expected. Stone size was the only independent predictor for stone-free status after mini-PNL. Patients with larger stones need to be informed about high risk of additional interventions. High BMI and high stone density do not represent a barrier for stone-free status after mini-PNL.

Keywords:
Kidney stones, Percutaneous nephrolithotomy, Stone-free rate, Stone-free status, Nephrolithiasis, Urolithiasis, PCNL, Minimally invasive-percutaneous nephrolithotomy, Mini-PCNL
1.
Zhang H, Hong TY, Li G, Jiang N, Hu C, Cui X, et al. Comparison of the Efficacy of Ultra-Mini PCNL, Flexible Ureteroscopy, and Shock Wave Lithotripsy on the Treatment of 1-2 cm Lower Pole Renal Calculi.
Urol Int
. 2018 Oct 23: 1–7.
2.
De S, Autorino R, Kim FJ, Zargar H, Laydner H, Balsamo R, et al. Percutaneous nephrolithotomy versus retrograde intrarenal surgery: a systematic review and meta-analysis.
Eur Urol
. 2015 Jan; 67(1): 125–37.
3.
Türk C, Petřík A, Sarica K, Seitz C, Skolarikos A, Straub M, et al. EAU Guidelines on Interventional Treatment for Urolithiasis.
Eur Urol
. 2016 Mar; 69(3): 475–82.
4.
Jiang H, Yu Z, Chen L, Wang T, Liu Z, Liu J, et al. Minimally Invasive Percutaneous Nephrolithotomy versus Retrograde Intrarenal Surgery for Upper Urinary Stones: A Systematic Review and Meta-Analysis.
BioMed Res Int
. 2017; 2017: 2035851.
5.
Xiang H, Chan M, Brown V, Huo YR, Chan L, Ridley L. Systematic review and meta-analysis of the diagnostic accuracy of low-dose computed tomography of the kidneys, ureters and bladder for urolithiasis.
J Med Imaging Radiat Oncol
. 2017 Oct; 61(5): 582–90.
6.
Sabnis RB, Jagtap J, Mishra S, Desai M. Treating renal calculi 1-2 cm in diameter with minipercutaneous or retrograde intrarenal surgery: a prospective comparative study.
BJU Int
. 2012 Oct; 110(8b 8 Pt B): E346–9.
7.
Kirac M, Bozkurt OF, Tunc L, Guneri C, Unsal A, Biri H. Comparison of retrograde intrarenal surgery and mini-percutaneous nephrolithotomy in management of lower-pole renal stones with a diameter of smaller than 15 mm.
Urolithiasis
. 2013 Jun; 41(3): 241–6.
8.
Ghani KR, Andonian S, Bultitude M, et al: Percutaneous Nephrolithotomy: Update, Trends, and Future Directions.
Eur Urol
. 2016 Aug; 70(2): 382–96.
9.
Heidenreich A, Desgrandschamps F, Terrier F. Modern approach of diagnosis and management of acute flank pain: review of all imaging modalities.
Eur Urol
. 2002 Apr; 41(4): 351–62.
10.
Smith-Bindman R, Aubin C, Bailitz J, Bengiamin RN, Camargo CA Jr, Corbo J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis.
N Engl J Med
. 2014 Sep; 371(12): 1100–10.
11.
Ray AA, Ghiculete D, Pace KT, Honey RJ. Limitations to ultrasound in the detection and measurement of urinary tract calculi.
Urology
. 2010 Aug; 76(2): 295–300.
12.
Kruck S, Anastasiadis AG, Herrmann TR, Walcher U, Abdelhafez MF, Nicklas AP, et al. Minimally invasive percutaneous nephrolithotomy: an alternative to retrograde intrarenal surgery and shockwave lithotripsy.
World J Urol
. 2013 Dec; 31(6): 1555–61.
13.
Akman T, Binbay M, Ozgor F, Ugurlu M, Tekinarslan E, Kezer C, et al. Comparison of percutaneous nephrolithotomy and retrograde flexible nephrolithotripsy for the management of 2-4 cm stones: a matched-pair analysis.
BJU Int
. 2012 May; 109(9): 1384–9.
14.
Ozturk U, Sener NC, Goktug HN, Nalbant I, Gucuk A, Imamoglu MA. Comparison of percutaneous nephrolithotomy, shock wave lithotripsy, and retrograde intrarenal surgery for lower pole renal calculi 10-20 mm.
Urol Int
. 2013; 91(3): 345–9.
15.
Smith-Bindman R, Moghadassi M, Griffey RT, Camargo CA Jr, Bailitz J, Beland M, et al. Computed Tomography Radiation Dose in Patients With Suspected Urolithiasis.
JAMA Intern Med
. 2015 Aug; 175(8): 1413–6.
16.
Jellison FC, Smith JC, Heldt JP, Spengler NM, Nicolay LI, Ruckle HC, et al. Effect of low dose radiation computerized tomography protocols on distal ureteral calculus detection.
J Urol
. 2009 Dec; 182(6): 2762–7.
17.
Srisubat A, Potisat S, Lojanapiwat B, Setthawong V, Laopaiboon M. Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones.
Cochrane Database Syst Rev
. 2014 Nov;(11):CD007044.
18.
Atmoko W, Birowo P, Rasyid N. Factors affecting stone free rate of primary percutaneous nephrolithotomy on staghorn calculi: a single center experience of 15 years.
F1000 Res
. 2016 Aug; 5: 2106.
19.
Soucy F, Ko R, Duvdevani M, Nott L, Denstedt JD, Razvi H. Percutaneous nephrolithotomy for staghorn calculi: a single center’s experience over 15 years.
J Endourol
. 2009 Oct; 23(10): 1669–73.
20.
Delakas D, Karyotis I, Daskalopoulos G, Lianos E, Mavromanolakis E. Independent predictors of failure of shockwave lithotripsy for ureteral stones employing a second-generation lithotripter.
J Endourol
. 2003 May; 17(4): 201–5.
© 2019 S. Karger AG, Basel
2019
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.