An evaluation of 646 stone patients treated on the HM4 extracorporeal shock wave lithotriptor

Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones

BACKGROUND

Stones in the urinary tract are a common medical problem in the general population. At present, the great expansion in minimally invasive techniques has led to the decrease in open surgery. Extracorporeal shock wave lithotripsy (ESWL) has been introduced as an alternative approach which disintegrates stones in the kidney and upper urinary tract through the use of shock waves. Nevertheless, as there are limitations with the success rate in ESWL, other minimally invasive modalities for kidney stones such as percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) are also widely applied. This is an update of a review first published in 2009.

OBJECTIVES

This review aimed to assess the effectiveness and complications of ESWL for kidney stones compared with PCNL or RIRS.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 3 March 2014 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the use of ESWL compared to PCNL or RIRS for kidney stone management.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed all the studies for inclusion. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Five studies (338 patients) were included, four studies compared ESWL to PCNL and one compared ESWL with RIRS. Random sequence generation was reported in three studies and unclear in two. Allocation concealment was not reported in any of the included studies. Blinding of participants and investigators could not be undertaken due to the nature of the interventions; blinding of outcome assessors was not reported. Reporting bias was judged to be low risk in all studies. One study was funded by industry and in one study the number of participants in each group was unbalanced.The success of treatment at three months was significantly greater in the PCNL compared to the ESWL group (3 studies, 201 participants: RR 0.46, 95% CI 0.35 to 0.62). Re-treatment (1 study, 122 participants: RR 1.81, 95% CI 0.66 to 4.99) and using auxiliary procedures (2 studies, 184 participants: RR 9.06, 95% CI 1.20 to 68.64) was significantly increased with ESWL group compared to PCNL. The efficiency quotient (EQ; used to assess the effectiveness of procedures) higher for PCNL than ESWL; however EQ decreased when stone size increased. Duration of treatment (MD -36.00 min, 95% CI -54.10 to -17.90) and hospital stay (1 study, 49 participants: MD -3.30 days, 95% CI -5.45 to -1.15) were significantly shorter in the ESWL group. Overall more complications were reported with PCNL, however we were unable to meta-analyse the included studies due to the differing outcomes reported and the timing of the outcome measurements.One study compared ESWL versus RIRS for lower pole kidney stones. The success of treatment was not significantly different at the end of the third month (58 participants: RR 0.91, 95% CI 0.64 to 1.30). Mean procedural time and mean hospital stay was reported to be longer in the RIRS group.

AUTHORS' CONCLUSIONS

Results from five small studies, with low methodological quality, indicated ESWL is less effective for kidney stones than PCNL but not significantly different from RIRS. Hospital stay and duration of treatment was less with ESWL. Larger RCTs with high methodological quality are required to investigate the effectiveness and complications of ESWL for kidney stones compared to PCNL if there is any technological progress in the non-invasive elimination of the residual fragments. Moreover, further research is required for the outcomes of ESWL and RIRS in lower and non-lower pole studies including PCNL versus RIRS.

Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones

BACKGROUND

Stones in the urinary tract are a common medical problem in the general population. At present, the great expansion in minimally invasive techniques has led to the decrease in open surgery. Extracorporeal shock wave lithotripsy (ESWL) has been introduced as an alternative approach which disintegrates stones in the kidney and upper urinary tract through the use of shock waves. Nevertheless, as there are limitations with the success rate in ESWL, other minimally invasive modalities for kidney stones such as percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) are also widely applied.

OBJECTIVES

To evaluate the effectiveness and complications of ESWL compared with PCNL or RIRS for managing kidney stones.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE, EMBASE and reference lists of articles without language restriction.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the use of ESWL compared to PCNL or RIRS for kidney stone management.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed all the studies for inclusion. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Three studies (214 patients) were included, however results could not be pooled. Two RCTs compared ESWL to PCNL. The success rate at three months for lower pole kidney stones was statistically higher for PCNL (RR 0.39, 95% CI 0.27 to 0.56). Re-treatment (RR 1.81, 95% CI 0.66 to 4.99) and using auxiliary procedures (RR 9.06, 95% CI 1.20 to 68.64) after PCNL were less compared to ESWL. The efficiency quotient (EQ) in PCNL was higher than ESWL. Hospital stay (MD -3.30 days, 95% CI -5.45 to -1.15), duration of treatment (MD -36.00 minutes, 95% CI -54.10 to -17.90) and complications were less for ESWL. One RCT compared ESWL versus RIRS for lower pole kidney stones. The success rate was not significantly different at the end of the third month (RR 0.91, 95% CI 0.64 to 1.30).

AUTHORS' CONCLUSIONS

Results from three small studies, with low methodological quality, indicated ESWL is less effective for lower pole kidney stones than PCNL but not significantly different from RIRS. Hospital stay and duration of treatment was less with ESWL. More RCTs are required to investigate the effectiveness and complications of ESWL for kidney stones compared to PCNL or RIRS.

Comparative study of extracorporeal shock wave lithotripsy outcomes for proximal and distal ureteric stones

OBJECTIVE

To assess the efficacy of extracorporeal shock wave lithotripsy (ESWL) monotherapy for isolated proximal ureteral calculi and compare it to that for isolated distal calculi.

PATIENT AND METHODS

We treated 68 patients with isolated ureteral stones using MPL 9000. Stones were located in the proximal and distal ureters in 44 and 24 patients, respectively. Patients were stratified according to stone burden and degree of obstruction. Data of all patients were prospectively collected for stone burden, stone localization, number of sessions, number of shock waves, stone-free rates (SFRs), complications, re-treatment rates and auxiliary procedures. Outcomes regarding ureteral localization were compared.

RESULTS

The overall SFR was 85.3% with a 41.2% re-treatment and 17.6% auxiliary procedure rate. The mean number of shock waves applied for each stone was not different among the two ureteral locations. The SFRs were 86.3% and 79.1% for proximal and distal ureteral stones, respectively (P=0.17). For the group with stones <100 mm(2), the SFR was 85.4% and 89.5% for the proximal and distal ureter, respectively. Although the degree of obstruction did not affect SFR of the entire group (P=0.12) and the proximal ureter group (P=0.96), it adversely affected SFR in the distal ureter (P=0.017).

CONCLUSIONS

ESWL outcomes for the ureteral calculi support the use of lithotripsy particularly for stones <100 mm(2). Treatment efficacy was not significantly different among stones localized in proximal and distal ureters. Degree of obstruction did not affect the ESWL outcomes in the proximal ureter, but it adversely affected SFR in the distal ureter.

Calyceal stones: fate of shock wave therapy with respect to stone localization

In a retrospective analysis the results of extracorporeal shock wave lithotripsy (ESWL) treatment were evaluated in patients with renal stones according to calyceal localization of treated stones. The 198 patients who underwent ESWL with the Dornier MPL 9000 were analyzed for success rate, complication rate, residual fragments, regrowth and recurrence rates. Totally 210 calyceal calculi located in different portions of the kidney have been comparatively evaluated. No major complications were noted during or after ESWL. Some minor complications such as flank pain, renal colic, haematuria were observed. Flank pain was observed during ESWL treatment especially in patients with upper calyceal stones. Although stone-free and residual fragment rates were similar in pelvic, upper and middle calyces, patients with lower calyceal and pelvicalyceal stones had high residual fragment rate and lower stone-free rate. Patients with stones in the lower calyces or pelvicalyces had high recurrence and regrowth rates (p < 0.05). ESWL has been considered as the optimal treatment modality for most upper urinary tract calculi. It is especially effective in patients with pelvic, upper and middle calyceal stones. Patients with lower calyceal stones often failed to eliminate the fragments, hence had high recurrence and regrowth rates.

Experience in 3,500 patients with urinary stones treated with the Dornier HM-4 bath-free lithotriptor

During a 3-year period, hundreds of patients underwent ESWL treatment with the Dornier HM-3 and HM-4 lithotriptors operating at our institution. Our experience in 3,500 patients treated with the HM-4 bath-free lithotriptor is reported. Patients with radiolucent or cystine stones, stones larger than 3 cm or staghorn calculi, multiple stones with a total burden of more than 3 cm and those not amenable to follow-up were excluded from the study. The overall stone-free rate was 70.7% and 81% at 1 and 3 months, respectively. The stone-free rates at 1 and 3 months were further determined by the exact location of each stone within the urinary tract. Stone-free rates at 3 months ranged from 90.84% for renal pelvic stones to 71.08% for lower calyceal stones, while the stone-free rates for ureteral calculi ranged from 80.85% for upper third unstented ureteral stones to 92.92% for lower ureteral stones. The overall complication rate was 6.02% with a 1.2% post-ESWL intervention rate (ureteroscopy or placement of percutaneous nephrostomy or stent).

Digitization and postprocessing of plain-film radiographs for assessment of stone fragmentation after extracorporeal shockwave lithotripsy

In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the radiographs taken before and 1 day afterward were initially assessed by conventional radiography and subsequently after standardized digitization and postprocessing. Clinical outcome and passage of stone fragments were reevaluated 3 weeks after ESWL. Using specially developed software routines, new disintegration parameters could be obtained by detecting the number of relevant minima in light-intensity distribution along the length axis of the concrement in digitized images. Comparing the digitized images before with those after ESWL, the concremental surface and axial length in digitized images on average showed no statistically significant difference. However, the number of visually and automatically detected light-intensity minima of the concrement region in digitized images obtained 1 day after ESWL was significantly higher than prior to ESWL and correlated significantly with the number of fissure lines in the conventional images. These new features in digitized images showed a high sensitivity in predicting later passage of stone fragments. Moreover, in six of the seven patients without detectable fissure lines in the early conventional radiographs but obvious signs of concretemental disintegration 3 weeks after ESWL, there was an increase in the number of light-intensity minima in the digitized images 1 day after ESWL. Our findings indicate that this method of digitization and post-processing of radiographs may improve the assessment of ESWL effectiveness by improving standardization in the analysis of all surveyed parameters and by offering new relevant disintegration measures.

Early experience with extracorporeal shockwave Dornier lithotriptor "compact"

One of the latest developments in extracorporeal shockwave lithotripsy (SWL) is a combination of an electromagnetic energy source with an upgraded parallel online ultrasound imaging for localization. The device is compact, requiring no significant installation or site preparation. Furthermore, it increases the margin of safety of SWL by virtue of the continuous ultrasound monitoring. A hundred sessions of SWL were performed on 88 patients using the Dornier Compact machine. Ninety three renal units having an average of 1.7 stones were treated (two had upper ureteric stones). Of the 135 stones, 2 (1.5%) were radiolucent and 4 (3%) were of faint opacity. Intravenous sedation was used in all patients except one 13-year-old patient, who required general anesthesia. Patients received an average of 2409 shocks per session, and the maximum power setting ranged from 1 to 6 (average 4.7). A plain film was obtained immediately before and after treatment. Early adverse effects were uncommon, and all were mild. Patients were followed by plain films at 2 weeks and 3 months. In 35 sessions (25 solitary and 10 multiple stones), the stones were considered completely fragmented; in 63 sessions, the stones (43 solitary and 20 multiple) were judged to be partial fragmented; and 2 sessions (solitary stones) resulted in poor fragmentation. The mean (+/- SD) stone dimension in the group with complete fragmentation was 9 +/- 4.8 (range 2-24) mm, compared with 11 +/- 6.3 (range 2-38) mm in those with no or partial fragmentation (P = 0.0095). After 2 weeks, 23 of 69 systems (33%) were stone free, while 46 showed residual stones.(ABSTRACT TRUNCATED AT 250 WORDS)