Common and widely used treatment options for lower pole renal stones (LPS) include shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), and percutaneous nephrolithotomy (PNL). Selecting the best treatment modality for stones smaller than 2 cm represents a controversial area in urology, because each treatment methods have their own advantages and disadvantages (1). SWL is a minimally invasive technique and it is usually the first choice method because of good patient tolerance and low complication rate. However, it is associated with lower success rate and higher retreatment rate (2). At the same time, with the advances in endourological instrumentation and technology, RIRS and minimally invasive percutaneous nephrolithotomy (MIP) have become more increasingly considered options for the treatment of medium sized LPS (3,4).
Donaldson and co-workers have recently published a very comprehensive review and meta-analysis to compare the benefits and harms of SWL, RIRS and PNL techniques in the treatment of medium-sized (≤2 cm) LPS in adults (5). Twelve articles reporting on 7 randomised controlled trials (RCTs) recruiting a total of 691 patients were included in this meta-analysis. Stone-free rate favoured PNL (96.3%) over RIRS (91.7%), and over SWL (54.5%). Stone size subgroup analyses revealed PNL and RIRS were considerably more effective than SWL for >10 mm stones, but the magnitude of benefit was markedly less for ≤10 mm stones. The major limitation of this review was the paucity of evidence for the comparison of PNL vs. RIRS and the lack of reliable evidence concerning outcomes other than stone-free rate (including complications, length of stay, analgesic requirement, and quality of life).
The European Association of Urology 2015 guidelines, state clearly that renal stones for 1–2 cm in diameter can be managed with SWL or endourological interventions (6). There is a decrease in the application of SWL with a parallel increase use of RIRS and MIP techniques due to better stone-free rate. In a recent meta-analysis, De et al. demonstrated that RIRS technique provides higher stone-free rates, shorter hospital stay, and reduced bleeding when compared with MIP for intermediate-sized (1–2 cm) renal stones (7). In another study, El-Nahas and colleagues showed significantly higher stone-free rate in RIRS (86%) compared with SWL (67%), whereas the complication rates were 4% in SWL and 13% in RIRS for lower pole stones 1 to 2 cm (8).
In the RIRS technique, laser energy can fragment all stones regardless of stone characteristics and patient’s body mass index (9). But success of SWL can be affected by various factors such as stone density, body mass index, stone composition and lower pole anatomy. However, Resorlu et al. reported that the success of RIRS is also affected by infundibulopelvic angle (IPA) of lower pole (10). Therefore, MIP can be selected as a first treatment option for lower pole stones with narrow IPA, because its stone-free is not dependent on anatomic features.
Surgeon experience, available instrumentation and the patient’s preference are the another important factors for selection of procedure (11). Therefore patients should be informed preoperatively about the advantages and disadvantages of these techniques.
Provenance: This is a Guest Perspective commissioned by Guest Editor Xiongbing Zu, MD, PhD (Department of Urology, Xiangya Hospital, Central South University, Changsha, China).
Conflicts of Interest: The authors have no conflicts of interest to declare.
- Resorlu B, Unsal A, Ziypak T, et al. Comparison of retrograde intrarenal surgery, shockwave lithotripsy, and percutaneous nephrolithotomy for treatment of medium-sized radiolucent renal stones. World J Urol 2013;31:1581-6. [Crossref] [PubMed]
- Kruck S, Anastasiadis AG, Herrmann TR, et al. Minimally invasive percutaneous nephrolithotomy: an alternative to retrograde intrarenal surgery and shockwave lithotripsy. World J Urol 2013;31:1555-61. [Crossref] [PubMed]
- Kumar A, Vasudeva P, Nanda B, et al. A Prospective Randomized Comparison Between Shock Wave Lithotripsy and Flexible Ureterorenoscopy for Lower Caliceal Stones ≤2 cm: A Single-Center Experience. J Endourol 2015;29:575-9. [Crossref] [PubMed]
- Mi Y, Ren K, Pan H, et al. Flexible ureterorenoscopy (F-URS) with holmium laser versus extracorporeal shock wave lithotripsy (ESWL) for treatment of renal stone <2 cm: a meta-analysis. Urolithiasis 2015. [Epub ahead of print]. [Crossref] [PubMed]
- Donaldson JF, Lardas M, Scrimgeour D, et al. Systematic review and meta-analysis of the clinical effectiveness of shock wave lithotripsy, retrograde intrarenal surgery, and percutaneous nephrolithotomy for lower-pole renal stones. Eur Urol 2015;67:612-6. [Crossref] [PubMed]
- Türk C, Knoll T, Petrik A, et al. Guidelines on urolithiasis: European Association of Urology Guidelines. 2011. Available at: http://www.uroweb.org/gls/pdf/18_Urolithiasis.pdf
- De S, Autorino R, Kim FJ, et al. Percutaneous nephrolithotomy versus retrograde intrarenal surgery: a systematic review and meta-analysis. Eur Urol 2015;67:125-37. [Crossref] [PubMed]
- El-Nahas AR, Ibrahim HM, Youssef RF, et al. Flexible ureterorenoscopy versus extracorporeal shock wave lithotripsy for treatment of lower pole stones of 10-20 mm. BJU Int 2012;110:898-902. [Crossref] [PubMed]
- Singh BP, Prakash J, Sankhwar SN, et al. Retrograde intrarenal surgery vs extracorporeal shock wave lithotripsy for intermediate size inferior pole calculi: a prospective assessment of objective and subjective outcomes. Urology 2014;83:1016-22. [Crossref] [PubMed]
- Resorlu B, Oguz U, Resorlu EB, et al. The impact of pelvicaliceal anatomy on the success of retrograde intrarenal surgery in patients with lower pole renal stones. Urology 2012;79:61-6. [Crossref] [PubMed]
- Zheng C, Yang H, Luo J, et al. Extracorporeal shock wave lithotripsy versus retrograde intrarenal surgery for treatment for renal stones 1-2 cm: a meta-analysis. Urolithiasis 2015;43:549-56. [Crossref] [PubMed]