In the era of flexible ureteroscopy is there still a place for Shock-wave lithotripsy?

Kidney Calculi; Lithotripsy; Ureteroscopy

INTRODUCTION

The prevalence of urolithiasis has increased to 8.8% in the United States of America, due to diet and lifestyle changes and associated increasing diabetes and obesity (¹). Urinary stones represent a significant economic burden both directly (treatment associated costs) and indirectly (e.g. time off work) (²). The emergence of a non-invasive intervention in 1980, shock wave lithotripsy (SWL), revolutionised the treatment or urinary calculi (³).

Miniaturisation and refinements to endourologists’ armamentarium over the past two decades have increased the efficacy and application of endoscopic stone management. The lower renal pole calyces can now be accessed with “near certainty” using modern flexible ureteroscopes (⁴). However, innovation and refinement to the technology and technique used for SWL have also improved its efficacy and reduced associated side-effects in recent decade (⁵). The optimal treatment modality for renal and ureteric calculi is therefore controversial (⁶).

EFFICACY

Small (<10 mm) renal stones respond well to SWL, with stone free rates (SFR) up to 91.5% reported by randomised controlled trials (RCTs) (⁶, ⁷). For medium sized (10-20 mm) middle or upper calyceal stones a large retrospective analysis found no difference between URS and SWL (92% vs. 87%; p>0.05): no randomised studies are available (⁸). Medium sized lower pole stones respond less well to lithotripsy as fragments clear less well from this dependent location: a recent meta-analysis showed a risk ratio (RR) of 1.50 (95% CI 1.20-1.87; p=0.0003) in favour of URS (SFR were 85-86% vs. 54-60%) (⁹). However, the benefit for URS was clinically insignificant for small lower pole renal stones in the same meta-analysis (RR 1.1 95%CI 1.03-1.19), although this remained statistically significant (p=0.004).

Distal ureteric calculi, although often more difficult to access with SWL, responded as effectively to SWL and URS for ≤20 mm radio-opaque stones (SFR 92.7% vs. 94.9%, p>0.05) in the only large RCT which used modern equipment (¹⁰). A large RCT examining the treatment of ≤10 mm proximal ureteric calculi found no significant difference in the SFR following SWL or URS (SFR 80% {46/58 patients} vs. 100% {52/52}, p>0.05) (¹¹). However, SWL was less effective than URS for >10mm proximal ureteric stones (88% vs. 60%, p<0.05) in the same RCT (¹²).

The efficacy and safety of SWL have been improved by using shock wave sources with larger focal zones and improved coupling mechanisms. Further improvements have been gained with modified techniques including pulse rate, ramping strategies, improved localisation with real-time monitoring (e.g. using colour duplex ultrasonography) and analgesics (limiting patient movement) (⁶, ¹³). Finally, adjuvant therapy following SWL might improve SFR as many as 1.77 fold, such as: medical expulsive therapy (¹⁴), potassium citrate (¹⁵), thiazide diuretics (¹⁶) and percussion, diuresis and inversion (PDI) therapy for lower pole stones (¹⁷). However, these adjuvants have yet to be included in randomised trials comparing SWL with adjuvant vs. endourological interventions.

Secondary outcomes: beyond stone free rates

Judgements regarding the relative benefits and harms of SWL and endourological techniques in the treatment of urolithiasis go beyond SFR. URS may have higher complication and re-treatment rates (⁶,¹²). A Cochrane review of RCTs comparing URS and SWL for ureteric stones found SWL has a lower auxiliary treatment rate and a shorter hospital stay (¹²). A recent systematic review of RCTs on lower pole renal stones found no difference in re-treatment or unplanned procedure rates between SWL and URS, although the quality of evidence (GRADE) was low or very low and incidence rates were low for both interventions (⁹).

For patients the most important outcome may be the effect of each treatment on their health related quality of life (QoL) including time off work and pain. Time till return to normal activities (including driving, non-strenuous activity and work) and post-operative analgesic requirements were shorter in two RCTs following a single session of SWL vs. URS for renal stones (¹⁸, ¹⁹). An RCT comparing URS and SWL for ureteric calculi similarly demonstrated less pain and a quicker convalescence for SWL (²⁰). However, there are currently no validated questionnaires to robustly assess QoL in the treatment of urolithiasis and as such the evidence for QoL outcomes is lacking.

Pearle et al. asked patients with ≤10 mm lower pole stones whether they would undergo the same treatment again after URS and SWL: patients favoured SWL: 63% vs. 90%; p=0.031 (¹⁸). However when patients underwent multiple SWL sessions for larger lower pole stones the same results were not replicated (¹⁹). Pearle et al., in a separate RCT, found a higher satisfaction following SWL vs. URS for ureteric calculi, although statistical significance was not reached (94% vs. 87%; p>0.05) (²⁰).

Ureteric stenting is more frequently required with URS than SWL, typically for 1-2weeks (⁶). Stent related symptoms including suprapubic pain, frequency and dysuria are commonly bothersome (²¹). One RCT reported 46% of patients required anticholinergics for stent related symptoms following URS (¹⁹). SWL is now typically conducted without general anaesthesia, which is typically required for URS and may necessitate an overnight hospital stay and/or present significant risks in co-morbid patients. Finally, renal scarring induced by SWL has been linked with renal impairment and diastolic hypertension (²²). However, no prospective study with long-term follow-up has proven this association (²³).

CONCLUSIONS

SWL produces acceptable SFR in the treatment of small and medium sized renal and ureteric calculi. URS may be more effective in terms of stone clearance, from a single session, particularly for larger lower pole renal stones. However, SWL is less invasive and has a lower complication rate than URS for renal stones. SWL is associated with a shorter hospital stay and quicker return to normal activities. SWL typically avoids stent insertion (with its associated bothersome symptoms) and general anaesthesia. Patients report a higher satisfaction rate with a single session of SWL than URS. Further technological and technique modifications will further improve the safety, efficacy and acceptability of SWL in the future.

ABBREVIATIONS

• SWL =  Shock wave lithotripsy
• URS =  Ureteroscopy

REFERENCES

• ¹
  Neisius A, Preminger GM. Stones in 2012: epidemiology, prevention and redefining therapeutic standards. Nat Rev Urol. 2013;10:75-7.
• ²
  Saigal CS, Joyce G, Timilsina AR; Urologic Diseases in America Project. Direct and indirect costs of nephrolithiasis in an employed population: opportunity for disease management? Kidney Int. 2005;68:1808-14.
• ³
  Chaussy C, Schmiedt E, Jocham D, Brendel W, Forssmann B, Walther V. First clinical experience with extracorporeally induced destruction of kidney stones by shock waves. J Urol. 1982;127:417-20.
• ⁴
  Raman JD, Pearle MS. Management options for lower pole renal calculi. Curr Opin Urol. 2008;18:214-9.
• ⁵
  Rassweiler JJ, Knoll T, Köhrmann KU, McAteer JA, Lingeman JE, Cleveland RO, et al. Shock wave technology and application: an update. Eur Urol.2011;59:784-96.
• ⁶
  Turk C, Knoll T, Petrik A, Sarica K, Skolarikos M, Straub C, Seitz C. Guidelines on urolithiasis [document on the Internet]. European Association of Urology, 2015. Arnhem. Available at: http://uroweb.org/guideline/urolithiasis [accessed 12.04.2015].
  » http://uroweb.org/guideline/urolithiasis
• ⁷
  Sener NC, Imamoglu MA, Bas O, Ozturk U, Goktug HN, Tuygun C, et al. Prospective randomized trial comparing shock wave lithotripsy and flexible ureterorenoscopy for lower pole stones smaller than 1 cm. Urolithiasis. 2014;42:127-31.
• ⁸
  Cecen K, Karadag MA, Demir A, Bagcioglu M, Kocaaslan R, Sofikerim M. Flexible Ureterorenoscopy versus Extracorporeal Shock Wave Lithotripsy for the treatment of upper/middle calyx kidney stones of 10-20 mm: a retrospective analysis of 174 patients. Springerplus. 2014;3:557.
• ⁹
  Donaldson JF, Lardas M, Scrimgeour D, Stewart F, MacLennan S, Lam TB, 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.
• ¹⁰
  Verze P, Imbimbo C, Cancelmo G, Creta M, Palmieri A, Mangiapia F, et al. Extracorporeal shockwave lithotripsy vs ureteroscopy as first-line therapy for patients with single, distal ureteric stones: a prospective randomized study. BJU Int. 2010;106:1748-52.
• ¹¹
  Salem HK. A prospective randomized study comparing shock wave lithotripsy and semirigid ureteroscopy for the management of proximal ureteral calculi. Urology. 2009;74:1216-21.
• ¹²
  Aboumarzouk OM, Kata SG, Keeley FX, McClinton S, Nabi G. Extracorporeal shock wave lithotripsy (ESWL) versus ureteroscopic management for ureteric calculi.Cochrane Database Syst Rev. 2012;5:CD006029.
• ¹³
  Rassweiler JJ, Knoll T, Köhrmann KU, McAteer JA, Lingeman JE, Cleveland RO, et al. Shock wave technology and application: an update. Eur Urol.2011;59:784-96.
• ¹⁴
  Zhu Y, Duijvesz D, Rovers MM, Lock TM. alpha-Blockers to assist Stone clearance after extracorporeal shock wave lithotripsy: a meta-analysis. BJU Int. 2010;106:256-61.
• ¹⁵
  Soygür T, Akbay A, Küpeli S. Effect of potassium citrate therapy on Stone recurrence and residual fragments after shockwave lithotripsy in lower caliceal calcium oxalate urolithiasis: a randomized controlled trial. J Endourol. 2002;16:149-52.
• ¹⁶
  Arrabal-Martín M, Fernández-Rodríguez A, Arrabal-Polo MA, García-Ruiz MJ, Zuluaga-Gómez A. Extracorporeal renal lithotripsy: evolution of residual lithiasis treated with thiazides. Urology. 2006;68:956-9.
• ¹⁷
  Liu LR, Li QJ, Wei Q, Liu ZH, Xu Y. Percussion, diuresis, and inversion therapy for the passage of lower pole kidney stones following shock wave lithotripsy. Cochrane Database Syst Rev. 2013;12:CD008569.
• ¹⁸
  Pearle MS, Lingeman JE, Leveillee R, Kuo R, Preminger GM, Nadler RB, et al. Prospective randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less. J Urol. 2008;179:S69-73.
• ¹⁹
  Singh V, Sinha RJ, Gupta DK, Pandey M. Prospective randomized comparison of retroperitoneoscopic pyelolithotomy versus percutaneous nephrolithotomy for solitary large pelvic kidney stones. Urol Int. 2014;92:392-5.
• ²⁰
  Pearle MS, Nadler R, Bercowsky E, Chen C, Dunn M, Figenshau RS, et al. Prospective randomized trial comparing shock wave lithotripsy and ureteroscopy for management of distal ureteral calculi. J Urol. 2001;166:1255-60.
• ²¹
  Haleblian G, Kijvikai K, de la Rosette J, Preminger G. Ureteral stenting and urinary stone management: a systematic review. J Urol. 2008;179:424-30.
• ²²
  Janetschek G, Frauscher F, Knapp R, Höfle G, Peschel R, Bartsch G. New onset hypertension after extracorporeal shock wave lithotripsy: age related incidence and prediction by intrarenal resistive index. J Urol. 1997;158:346-51.
• ²³
  Skolarikos A, Alivizatos G, de la Rosette J. Extracorporeal shock wave lithotripsy 25 years later: complications and their prevention. Eur Urol. 2006;50:981-90; discussion 990.

Publication Dates

• Publication in this collection
  Mar-Apr 2015