Original Paper
Urologia Internationalis
Received: January 27, 2014 Accepted after revision: May 9, 2014 Published online: August 27, 2014
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
Retrograde Intrarenal Surgery versus Percutaneous Nephrolithotomy for Treatment of Renal Stones >2 cm: A Meta-Analysis Changjian Zheng Bo Xiong Hongzhi Wang Jun Luo Chenggou Zhang Wei Wei Yarong Wang Department of Urology, People’s Hospital of Bishan District, Bishan, China
Abstract Objective: To systematically review the efficacy and safety of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) for the treatment of renal calculi >2 cm. Methods: We searched PubMed, Cochrane Library, Embase and the Chinese Biomedical Literature Database about RIRS and PCNL for the treatment of renal stones. The retrieval time ended in December 2013. All clinical trials were retrieved and their included references investigated. Two reviewers independently assessed the quality of all included studies, and the eligible studies were included and analyzed using the RevMan 5.2 software. Results: Two randomized controlled trials and six clinical controlled trials were included, involving a total of 590 patients. Our meta-analysis showed that there were not significant differences in stonefree rate (relative risk [RR] = 0.95, 95% confidence interval (CI) 0.88–1.02, p = 0.11) and fever (RR = 0.95, 95% CI 0.54–1.67, p = 0.85) between RIRS and PCNL. We found that hospital stay (weighted mean difference [WMD] = –2.10, 95% CI –3.08
© 2014 S. Karger AG, Basel 0042–1138/14/0934–0417$39.50/0 E-Mail [email protected] www.karger.com/uin
to –1.11, p < 0.10) and bleeding (RR = 0.20, 95% CI 0.06–0.68, p = 0.01) were lower and operation time was longer (WMD = 19.11, 95% CI 7.83–30.39, p < 0.10) for RIRS. Conclusion: RIRS is a safe and effective procedure. It can successfully treat patients with stones >2 cm with a high stone-free rate and significantly reduce hospital stay without increasing complications. RIRS can be used as an alternative treatment to PCNL in selected cases with larger renal stones. However, further randomized trials are needed to confirm these findings. © 2014 S. Karger AG, Basel
Introduction
Since Fernström and Johannson [1] first reported percutaneous nephrolithotomy (PCNL) in 1976, it has been widely accepted for the management of renal stones. Nowadays, PCNL has become the standard treatment for renal stones [2, 3]. Although stone-free rates exceeding 95% have been reported with PCNL, the largest U.S. national inpatient sample study [4] showed that PCNL complication was up to 15.6% and the three most common reported complications were urosepsis/urinary tract infection (8.4%), blood transfusions (4.4%) and sepsis Changjian Zheng Department of Urology People’s Hospital of Bishan District Bishan, Chongqing 402760 (China) E-Mail zcj2010110649 @ sina.cn
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Key Words Percutaneous nephrolithotomy · Retrograde intrarenal surgery · Meta-analysis
(2.4%). More than that, patient mortality was very high (0.3%). Therefore, novel endoscopic imaging techniques are urgently needed to reduce the complications of renal stones. Meanwhile, with the advances in flexible ureteroscopic instrumentation and holmium laser lithotripsy, retrograde intrarenal surgery (RIRS) has become an increasingly considered option for intrarenal stone removal. Some studies [5, 6] reported a stone-free rate near to 92% in patients with large stones. RIRS has been widely accepted in the management of larger renal stones as an alternative to PCNL. However, it remains unclear which is the superior modality. Recently, several randomized controlled trials (RCTs) and clinical controlled trials (CCTs) have directly compared the efficacy and safety of RIRS versus PCNL for renal calculi, but to date there has been no systematic review and meta-analysis to evaluate the effectiveness of RIRS. Therefore, it is necessary to conduct a systematic review and meta-analysis of evidence from controlled trials to evaluate the efficacy and safety of RIRS.
ment and score table of non-randomized controlled clinical trials from the Chinese Journal of Evidence-Based Medicine [8], which assessed studies using information on blinding of outcome, patients who were lost to follow-up, exit from or breach of the treatment regimen, baseline of research and confounding factors. Data Analysis All meta-analyses were performed using the RevMan 5.2 software. Effect size and statistical analysis methods were chosen according to the type of data and the purpose of the assessment. For continuous variables (mean operation and hospital stay), if results had the same units of measurement, we used weighted mean difference (WMD), otherwise we used standardized mean difference. For categorical variables (stone-free rate and complication rate), statistical analysis was carried out using relative risk (RR) and 95% confidence interval (CI). Heterogeneity among the studies was assessed using χ2 statistics (p = 0.10), fixed effect models were calculated for homogeneous data, and random effects analysis was performed for heterogeneous data. The results of the meta-analysis were expressed using forest plots.
Results
Search Strategy As required by the Cochrane Reviewers’ Handbook, two investigators conducted the search. Relevant trials were obtained from the following sources: PubMed, Cochrane Library, Embase and the Chinese Biomedical Literature Database and hand searching of relevant congress abstracts and journals. The retrieval time ended in December 2013. We used the following key words related to kidney stone: ‘renal calculus’, ‘calculus of kidney’, ‘percutaneous nephrolithotomy’, ‘PCNL’, ‘minimally invasive percutaneous nephrolithotomy’, ‘MPCNL’, ‘miniperc’, ‘flexible nephroscopy’, ‘flexible ureteroscopy’, ‘flexible URS’, ‘fURS’, ‘retrograde intrarenal surgery’ and ‘RIRS’. Inclusion Criteria The selected studies were included based on the following set of inclusion criteria: (1) experimental studies (RCTs or CCTs) comparing RIRS versus PCNL for the treatment of patients with renal calculi; (2) reports of at least one of the following outcomes: stone-free rates, mean operation time, complication rates and mean hospital stay; (3) renal stones >2 cm in diameter. Data Extraction and Quality Assessment The two investigators (C. Zheng and B. Xiong) independently screened the documents according to the inclusion and exclusion criteria. We appraised both quality and content. Any disagreements were resolved by discussion. We independently extracted the following data from each study: first author, year of publication, baseline patient characteristics, intervention and outcome measures. We applied the ‘assessing risk of bias’ table recommended in the Cochrane Handbook 5.2 to assess the risk of bias of the RCT articles included [7]. For CCT articles, we used the quality assess-
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Urol Int 2014;93:417–424 DOI: 10.1159/000363509
Study Description A total of 1,102 studies were initially identified. After an initial screening of titles and abstracts, 27 studies were thought to meet the inclusion criteria. With further screening of full texts, 19 studies were excluded. Finally, 8 studies were included in the meta-analysis, 2 RCTs and 6 controlled trials, published between 2009 and 2013. The literature screening process is shown in figure 1. Table 1 shows the methodological quality of the included studies. The trial by Pan et al. [9] is a RCT and scored 3 points by Jadad. The trial by Bryniarski et al. [10] is a RCT, describing the randomization method and scoring 4 points by Jadad. None of studies used an intentionto-treat design. The baseline characteristics of the included studies are summarized in table 2. Stone-Free Rate A comparison of the stone-free rate between the RIRS and the PCNL group is shown in figure 2. The eight included studies [9–16] reported postoperative stone-free rates and the pooled result of the meta-analysis indicated that there was no statistically significant difference between the RIRS and PCNL group (RR = 0.95, 95% CI 0.88–1.02, p = 0.15) with statistical heterogeneity (I2 = 55%). Operation Time Operation time was measured in seven studies [9, 10, 12–16] including 551 patients; the meta-analysis of the Zheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Materials and Methods
Total citations identified from initial search (n = 1,102) Citations excluded after screening titles and/or abstract (n = 1,075) Potential references reviewed for detailed evaluation (n = 27)
Excluded studies (n = 19) Reasons for exclusion: Disagree with the inclusion criteria (n = 17) Lack of detailed patient characteristics (n = 2)
Studies included in the review (n = 8) RCTs (n = 2) CCTs (n = 6)
Fig. 1. Study flow chart.
seven studies (fig. 3) showed that the mean operation time of the RIRS group was significantly longer than that of the PCNL group, by a mean value of 19.11 min (p < 0.05, 95% CI 7.83–30.39). Hospital Stay Six studies [9, 10, 12, 13, 15, 16] with data available for combination reported hospital stay. The pooled result showed that the hospital stay in the RIRS group was significantly decreased, with pooled WMD values of –2.10 (95% CI –3.08 to –1.11, p < 0.0001) (fig. 4). Complications Six studies [9, 10, 12, 13, 15, 16] provided data on the fever rate after operation (>38 ° C) between the RIRS and the PCNL group. We also used RR for statistical analysis. The data was heterogeneous (I2 = 0%), so we used a fixed effects model. The meta-analysis showed that there was no statistically significant difference between the RIRS and the PCNL group (RR = 0.95, 95% CI 0.54–1.67, p = 0.85). Five studies [10, 12, 13, 15, 16] reported intra- and postoperative bleeding. The pooled result showed that the bleeding rate in the total RIRS and PCNL groups was 0.5 and 6.87%, respectively, and the two groups had different risk for bleeding, with significant statistical difference, with RR values of 0.20 (95% CI 0.06–0.68, p = 0.01), which
Study (first author)
Design
Allocation Completeness concealment of follow-up
Baseline
Pan [9] Bryniarski [10] Hyams [11] Akman [12] Yang [13] Zhu [14] Xiao [15] Cao [16]
RCT RCT CCT CCT CCT CCT CCT CCT
NA yes NA NA NA NA NA NA
consistency consistency consistency consistency consistency consistency consistency consistency
reported reported reported reported reported reported reported reported
NA = Not available (insufficient information provided). Blinding: NA for all studies.
RIRS versus PCNL for Treatment of Renal Stones >2 cm
showed significant difference between the RIRS and the PCNL group. Three studies [9, 12, 16] provided data on other complications (deterioration of renal function and ureter steinstrasse). The pooled results showed that there was no significant difference between the RIRS and the PCNL group, with RR values of 1.18 (95% CI 0.47–2.95, p = 0.73) (fig. 5).
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
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Table 1. Quality evaluation of included studies
Study or subgroup (first author)
Experimental
Control
events
total
events
total
Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Hyams, 2009 [11] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13] Zhu, 2013 [14]
32 28 32 18 40 33 60 17
34 32 34 19 56 36 64 23
33 30 34 20 57 37 41 22
34 32 36 20 59 42 45 24
Weight, RR % M-H, random, 95% CI 16.4 11.5 15.2 12.8 10.5 12.3 15.6 5.8
0.97 (0.88, 1.07) 0.93 (0.80, 1.09) 1.00 (0.89, 1.12) 0.95 (0.82, 1.09) 0.74 (0.62, 0.88) 1.04 (0.90, 1.21) 1.03 (0.92, 1.15) 0.81 (0.61, 1.06)
Total (95% CI) 298 292 100.0 Total events 260 274 Heterogeneity: τ2 = 0.01, χ2 = 15.66, d.f. = 7 (p = 0.03), I2 = 55% Test for overall effect: Z = 1.45 (p = 0.15)
0.95 (0.88, 1.02)
RR M-H, random, 95% CI
0.5 0.7 1 1.5 2 Favors Favors experimental control
Fig. 2. Forest plot showing the stone-free rate between RIRS and PCNL.
Study (first author)
Year
Sample size (RIRS/PCNL)
Age (RIRS/PCNL)
Male:female (RIRS/PCNL)
Outcome measures
Pan [9]
2013
56/59
49.32 ± 13.7/ 49.37 ± 14.2
36:20/ 37:22
stone-free rate; operation time; hospital stay, complications
Bryniarski [10]
2012
32/32
53.4 ± 12.4/ 51.8 ± 11.8
15:17/ 16:16
stone-free rate; operation time; hospital stay, complications
Hyams [11]
2009
19/20
56/48
11:8/ 11:9
stone-free rate
Akman [12]
2012
34/34
44.5 ± 16.5/ 44.8 ± 17.1
18:16/ 16:18
stone-free rate; operation time; hospital stay, complications
Yang [13]
2013
64/45
21 – 73
71/38
stone-free rate; operation time; hospital stay, complications
Zhu [14]
2013
23/24
44.13 ± 7.11
NA
stone-free rate; operation time
Xiao [15]
2013
36/42
23 – 61/ 28 – 50
17:19/ 22:20
stone-free rate; operation time; hospital stay, complications
Cao [16]
2013
34/36
NA
NA
stone-free rate; operation time; hospital stay, complications
Discussion
Renal calculi are a very common illness having affected 5% of the population in the United States in the last 10 years [17], and recent studies have shown that the incidence of kidney stones in the United States and other 420
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
parts of the world has increased [18]. Although the European Association of Urology (EAU) [19], the American Urological Association (AUA) [2] and the Japanese urolithiasis clinical guideline [20] recommended PCNL as the first method of choice for kidney stones >2 cm and also for complex renal stones. Compared with other proZheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Table 2. Basic characteristics of included studies
Study or subgroup (first author) Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13] Zhu, 2013 [14]
Experimental mean 58.2 85 58.2 73.07 146.94 117 68.22
Control
SD
total
mean
SD
total
13.4 17.6 13.4 13.5 13.06 36.5 9.32
34 32 34 56 36 64 23
38.7 100.1 38.7 62.39 101.95 90 44.32
11.6 29.9 11.6 10.6 10.3 18.2 10.34
34 32 36 59 42 45 24
Weight, % 14.6 13.0 14.6 14.9 14.7 13.5 14.7
Total (95% CI) 279 272 100.0 Heterogeneity: τ2 = 217.51, χ2 = 136.85, d.f. = 6 (p < 0.00001), I2 = 96% Test for overall effect: Z = 3.32 (p = 0.0009)
Mean difference IV, random, 95% CI
Mean difference IV, random, 95% CI
19.50 (13.54, 25.46) –15.10 (–27.12, –3.08) 19.50 (13.61, 25.39) 10.68 (6.23, 15.13) 44.99 (39.71, 50.27) 27.00 (16.58, 37.42) 23.90 (18.28, 29.52) 19.11 (7.83, 30.39) –200 –100 1 Favors experimental
100 200 Favors control
Fig. 3. Forest plot showing the mean operation time between RIRS and PCNL.
Study or subgroup (first author) Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13]
Experimental
Control
mean SD
total
mean SD
total
1.25 6.8 1.25 1.95 3.22 2.08
34 32 34 56 36 64
2.56 11.3 2.56 4.47 6.26 2.92
34 32 36 59 42 45
1.56 3.4 1.56 1.3 1.31 0.1
1.42 4.4 1.42 1.4 1.01 0.15
Weight, Mean difference % IV, random, 95% CI 17.2 10.9 17.2 18.0 17.9 18.8
–1.31 (–2.02, –0.60) –4.50 (–6.43, –2.57) –1.31 (–2.01, –0.61) –2.52 (–3.01, –2.03) –3.04 (–3.57, –2.51) –0.84 (–0.89, –0.79)
Total (95% CI) 256 248 100.0 Heterogeneity: τ2 = 1.34, χ2 = 126.11, d.f. = 5 (p < 0.00001), I2 = 96% Test for overall effect: Z = 4.18 (p < 0.0001)
–2.10 (–3.08, –1.11)
Mean difference IV, random, 95% CI
–20
–10 0 Favors experimental
10 20 Favors control
cedures, including extracorporeal shock wave lithotripsy, the high success rates of PCNL, exceeding 95%, have overshadowed its more invasive nature [21]. The global study showed that the major complications of PCNL, including blood transfusions (11.2–17.5%), urinary extravasation (7.2%) and high-grade fever, occurred in 32.1% of patients. Thanks to the recent advances in endoscopic procedures and equipments [22], flexible ureteroscopes with holmium laser lithotripsy have allowed a more efficient and safer treatment of stones through the natural orifice to reach all renal calyces since Marshall [23] first reported the use of flexible ureteroscopes. People then began to
deal with small kidney stones [24, 25]. A prospective comparative study come from India [26] showed that stone clearance in both modalities was high and complications were low in the mini-percutaneous and RIRS groups. Estrade et al. [27] recommended RIRS as a firstline treatment regardless of size and number of kidney stones if extracorporeal shock wave lithotripsy and PCNL are contraindicated or if their predictable results are poor (hard stones, morbid obesity, lower pole stones) or if stone access is difficult (intradiverticular). The latest digital ureteroscope has excellent image quality and easy handling, so urologists try to handle large stones. Several single-institution case series of RIRS for
RIRS versus PCNL for Treatment of Renal Stones >2 cm
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
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Fig. 4. Forest plot showing the hospital stay between RIRS and PCNL.
Study or subgroup (first author) 6.1.1. Fever Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13]
Experimental
Control
events
total
events
total
1 8 1 4 3 3
34 32 34 56 36 64
2 9 2 2 4 2
34 32 36 59 42 45
9.6 43.0 9.3 9.3 17.6 11.2
0.50 (0.05, 5.26) 0.89 (0.39, 2.01) 0.53 (0.05, 5.57) 2.11 (0.40, 11.05) 0.88 (0.21, 3.65) 1.05 (0.18, 6.06)
248
100.0
0.95 (0.54, 1.67)
34 32 36 42 45
16.8 33.5 16.3 21.7 11.8
0.20 (0.01, 4.02) 0.20 (0.02, 1.62) 0.21 (0.01, 4.25) 0.17 (0.01, 3.11) 0.24 (0.01, 5.66)
189
100.0
0.20 (0.06, 0.68)
34 36 59
12.8 24.9 62.3
2.00 (0.19, 21.03) 1.06 (0.16, 7.10) 1.05 (0.32, 3.44)
Subtotal (95% CI) 256 Total events 20 21 Heterogeneity: χ2 = 1.46, d.f. = 5 (p = 0.92), I2 = 0% Test for overall effect: Z = 0.18 (p = 0.85) 6.1.2. Bleeding Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Xiao, 2013 [15] Yang, 2013 [13]
0 1 0 0 0
34 32 34 36 64
2 5 2 3 1
Subtotal (95% CI) 200 Total events 1 13 Heterogeneity: χ2 = 0.03, d.f. = 4 (p = 1.00), I2 = 0% Test for overall effect: Z = 2.58 (p = 0.010) 6.1.3. Other Akman, 2012 [12] Cao, 2013 [16] Pan, 2013 [9]
2 2 5
34 34 56
1 2 5
Weight, RR % M-H, fixed, 95% CI
Subtotal (95% CI) 124 129 100.0 Total events 9 8 Heterogeneity: χ2 = 0.24, d.f. = 2 (p = 0.89), I2 = 0% Test for overall effect: Z = 0.35 (p = 0.73) Test for subgroup differences: χ2 = 5.96, d.f. = 2 (p = 0.05), I2 = 66.5%
RR M-H, fixed, 95% CI
1.18 (0.47, 2.95)
0.01
0.1 1 Favors experimental
10 Favors control
100
large renal stones have been reported [28–36]. In 1998, Grasso et al. [28] first reported 48 patients with upper urinary tract and minor staghorn calculi >2 cm who underwent RIRS, with an 81% (34 of 45 renal and 20 of 21 ureteral) stone-free rate in a single procedure. Second-stage procedures were carried out in 18 patients (8 of 15 large renal and 1 of 3 complex ureteral stone burdens), and the success rate increased to 94% without intraoperative complications. The study by El-Anany et al. [29] showed that stone fragmentation was achieved in only 23 (77%) patients because of poor visualization. In recent years, more and more doctors have been able to skillfully oper422
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
ate the flexible ureteroscope and determine the efficacy of ureteroscopy as an alternative to PCNL to tackle large renal stones. RIRS had an average stone-free rate of around 91–97.5% for stones >2 cm, with an average number of procedures of no more than two [5, 30–35]. Takazawa et al. [6] reported that in kidney stones 2–4 cm in size, after three procedures the stone-free rate was up to 100% with no major intraoperative complications. Mariani [36] reported 16 patients with kidney stones >4 cm and a stone clearance rate of up to 88%. In our review, we found that the difference between the experimental and the control group regarding stone-free rate was not that dramatic in Zheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Fig. 5. Forest plot showing the complications between RIRS and PCNL.
the respective included trial. Six studies [9–16] in this review showed that RIRS with holmium laser was as efficient as PCNL in the treatment of selected cases with larger renal stones. In order to improve the stone clearance rate, we can combine PCNL and flexible ureteroscopy for the treatment of large or complex renal stones [37, 38]. Flexible nephrolithotomy with a stone basket can easy reach each calyx, thus improving the stone clearance rate. RIRS with the small caliber ureteroscope is an endoscopic surgery through the natural orifice, thus renal parenchymal damage can be avoided. The overall complication rates have decreased, with major complication rates reported to be 2 cm with a high stone-free rate and significantly reduce hospital stay and bleeding without increasing complications. However, further randomized trials are needed to confirm these findings.
Disclosure Statement No competing financial interests exist.
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16 Cao SY, Xiong J, Zhou XJ, et al: Comparison of percutaneous nephrolithotomy and flexible ureteroscope for the management of 2– 4 cm renal stones. Int J Urol Nephrol 2013;1: 34–36. 17 Stamatelou KK, Francis ME, Jones CA, et al: Time trends in reported prevalence of kidney stones in the United States: 1976–1994. Kidney Int 2003;63:1817–1823. 18 Romero V, Akpinar H, Assimos DG: Kidney stones: a global picture of prevalence, incidence, and associated risk factors. Rev Urol 2010;12:e86–e96. 19 Türk C, Knoll T, Petrik A, Sarica C, Skolarikos A, Straub M, Seitz C: Guidelines on urolithiasis. European Association of Urology, 2013. Available at http://www.uroweb.org/gls/pdf/ 21_Urolithiasis_LR.pdf. 20 Mugiya S: Guidelines on urolithiasis: update of diagnosis and treatment. Hinyokika Kiyo 2012;58:703–706. 21 De la Rosette J, Assimos D, Desai M, et al: The Clinical Research Office of the Endourological Society percutaneous nephrolithotomy global study: indications, complications, and outcomes in 5,803 patients. J Endourol 2011; 25:11–17. 22 Kerbl K, Rehman J, Landman J, Lee D, Sundaram C, Clayman RV: Current management of urolithiasis: progress or regress? J Endourol 2002;16:281–288. 23 Marshall VF: Fiber optics in urology. J Urol 1964;91:110–114.
Urologia Internationalis
Received: January 27, 2014 Accepted after revision: May 9, 2014 Published online: August 27, 2014
Urol Int 2014;93:417–424 DOI: 10.1159/000363509
Retrograde Intrarenal Surgery versus Percutaneous Nephrolithotomy for Treatment of Renal Stones >2 cm: A Meta-Analysis Changjian Zheng Bo Xiong Hongzhi Wang Jun Luo Chenggou Zhang Wei Wei Yarong Wang Department of Urology, People’s Hospital of Bishan District, Bishan, China
Abstract Objective: To systematically review the efficacy and safety of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) for the treatment of renal calculi >2 cm. Methods: We searched PubMed, Cochrane Library, Embase and the Chinese Biomedical Literature Database about RIRS and PCNL for the treatment of renal stones. The retrieval time ended in December 2013. All clinical trials were retrieved and their included references investigated. Two reviewers independently assessed the quality of all included studies, and the eligible studies were included and analyzed using the RevMan 5.2 software. Results: Two randomized controlled trials and six clinical controlled trials were included, involving a total of 590 patients. Our meta-analysis showed that there were not significant differences in stonefree rate (relative risk [RR] = 0.95, 95% confidence interval (CI) 0.88–1.02, p = 0.11) and fever (RR = 0.95, 95% CI 0.54–1.67, p = 0.85) between RIRS and PCNL. We found that hospital stay (weighted mean difference [WMD] = –2.10, 95% CI –3.08
© 2014 S. Karger AG, Basel 0042–1138/14/0934–0417$39.50/0 E-Mail [email protected] www.karger.com/uin
to –1.11, p < 0.10) and bleeding (RR = 0.20, 95% CI 0.06–0.68, p = 0.01) were lower and operation time was longer (WMD = 19.11, 95% CI 7.83–30.39, p < 0.10) for RIRS. Conclusion: RIRS is a safe and effective procedure. It can successfully treat patients with stones >2 cm with a high stone-free rate and significantly reduce hospital stay without increasing complications. RIRS can be used as an alternative treatment to PCNL in selected cases with larger renal stones. However, further randomized trials are needed to confirm these findings. © 2014 S. Karger AG, Basel
Introduction
Since Fernström and Johannson [1] first reported percutaneous nephrolithotomy (PCNL) in 1976, it has been widely accepted for the management of renal stones. Nowadays, PCNL has become the standard treatment for renal stones [2, 3]. Although stone-free rates exceeding 95% have been reported with PCNL, the largest U.S. national inpatient sample study [4] showed that PCNL complication was up to 15.6% and the three most common reported complications were urosepsis/urinary tract infection (8.4%), blood transfusions (4.4%) and sepsis Changjian Zheng Department of Urology People’s Hospital of Bishan District Bishan, Chongqing 402760 (China) E-Mail zcj2010110649 @ sina.cn
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Key Words Percutaneous nephrolithotomy · Retrograde intrarenal surgery · Meta-analysis
(2.4%). More than that, patient mortality was very high (0.3%). Therefore, novel endoscopic imaging techniques are urgently needed to reduce the complications of renal stones. Meanwhile, with the advances in flexible ureteroscopic instrumentation and holmium laser lithotripsy, retrograde intrarenal surgery (RIRS) has become an increasingly considered option for intrarenal stone removal. Some studies [5, 6] reported a stone-free rate near to 92% in patients with large stones. RIRS has been widely accepted in the management of larger renal stones as an alternative to PCNL. However, it remains unclear which is the superior modality. Recently, several randomized controlled trials (RCTs) and clinical controlled trials (CCTs) have directly compared the efficacy and safety of RIRS versus PCNL for renal calculi, but to date there has been no systematic review and meta-analysis to evaluate the effectiveness of RIRS. Therefore, it is necessary to conduct a systematic review and meta-analysis of evidence from controlled trials to evaluate the efficacy and safety of RIRS.
ment and score table of non-randomized controlled clinical trials from the Chinese Journal of Evidence-Based Medicine [8], which assessed studies using information on blinding of outcome, patients who were lost to follow-up, exit from or breach of the treatment regimen, baseline of research and confounding factors. Data Analysis All meta-analyses were performed using the RevMan 5.2 software. Effect size and statistical analysis methods were chosen according to the type of data and the purpose of the assessment. For continuous variables (mean operation and hospital stay), if results had the same units of measurement, we used weighted mean difference (WMD), otherwise we used standardized mean difference. For categorical variables (stone-free rate and complication rate), statistical analysis was carried out using relative risk (RR) and 95% confidence interval (CI). Heterogeneity among the studies was assessed using χ2 statistics (p = 0.10), fixed effect models were calculated for homogeneous data, and random effects analysis was performed for heterogeneous data. The results of the meta-analysis were expressed using forest plots.
Results
Search Strategy As required by the Cochrane Reviewers’ Handbook, two investigators conducted the search. Relevant trials were obtained from the following sources: PubMed, Cochrane Library, Embase and the Chinese Biomedical Literature Database and hand searching of relevant congress abstracts and journals. The retrieval time ended in December 2013. We used the following key words related to kidney stone: ‘renal calculus’, ‘calculus of kidney’, ‘percutaneous nephrolithotomy’, ‘PCNL’, ‘minimally invasive percutaneous nephrolithotomy’, ‘MPCNL’, ‘miniperc’, ‘flexible nephroscopy’, ‘flexible ureteroscopy’, ‘flexible URS’, ‘fURS’, ‘retrograde intrarenal surgery’ and ‘RIRS’. Inclusion Criteria The selected studies were included based on the following set of inclusion criteria: (1) experimental studies (RCTs or CCTs) comparing RIRS versus PCNL for the treatment of patients with renal calculi; (2) reports of at least one of the following outcomes: stone-free rates, mean operation time, complication rates and mean hospital stay; (3) renal stones >2 cm in diameter. Data Extraction and Quality Assessment The two investigators (C. Zheng and B. Xiong) independently screened the documents according to the inclusion and exclusion criteria. We appraised both quality and content. Any disagreements were resolved by discussion. We independently extracted the following data from each study: first author, year of publication, baseline patient characteristics, intervention and outcome measures. We applied the ‘assessing risk of bias’ table recommended in the Cochrane Handbook 5.2 to assess the risk of bias of the RCT articles included [7]. For CCT articles, we used the quality assess-
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Study Description A total of 1,102 studies were initially identified. After an initial screening of titles and abstracts, 27 studies were thought to meet the inclusion criteria. With further screening of full texts, 19 studies were excluded. Finally, 8 studies were included in the meta-analysis, 2 RCTs and 6 controlled trials, published between 2009 and 2013. The literature screening process is shown in figure 1. Table 1 shows the methodological quality of the included studies. The trial by Pan et al. [9] is a RCT and scored 3 points by Jadad. The trial by Bryniarski et al. [10] is a RCT, describing the randomization method and scoring 4 points by Jadad. None of studies used an intentionto-treat design. The baseline characteristics of the included studies are summarized in table 2. Stone-Free Rate A comparison of the stone-free rate between the RIRS and the PCNL group is shown in figure 2. The eight included studies [9–16] reported postoperative stone-free rates and the pooled result of the meta-analysis indicated that there was no statistically significant difference between the RIRS and PCNL group (RR = 0.95, 95% CI 0.88–1.02, p = 0.15) with statistical heterogeneity (I2 = 55%). Operation Time Operation time was measured in seven studies [9, 10, 12–16] including 551 patients; the meta-analysis of the Zheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Materials and Methods
Total citations identified from initial search (n = 1,102) Citations excluded after screening titles and/or abstract (n = 1,075) Potential references reviewed for detailed evaluation (n = 27)
Excluded studies (n = 19) Reasons for exclusion: Disagree with the inclusion criteria (n = 17) Lack of detailed patient characteristics (n = 2)
Studies included in the review (n = 8) RCTs (n = 2) CCTs (n = 6)
Fig. 1. Study flow chart.
seven studies (fig. 3) showed that the mean operation time of the RIRS group was significantly longer than that of the PCNL group, by a mean value of 19.11 min (p < 0.05, 95% CI 7.83–30.39). Hospital Stay Six studies [9, 10, 12, 13, 15, 16] with data available for combination reported hospital stay. The pooled result showed that the hospital stay in the RIRS group was significantly decreased, with pooled WMD values of –2.10 (95% CI –3.08 to –1.11, p < 0.0001) (fig. 4). Complications Six studies [9, 10, 12, 13, 15, 16] provided data on the fever rate after operation (>38 ° C) between the RIRS and the PCNL group. We also used RR for statistical analysis. The data was heterogeneous (I2 = 0%), so we used a fixed effects model. The meta-analysis showed that there was no statistically significant difference between the RIRS and the PCNL group (RR = 0.95, 95% CI 0.54–1.67, p = 0.85). Five studies [10, 12, 13, 15, 16] reported intra- and postoperative bleeding. The pooled result showed that the bleeding rate in the total RIRS and PCNL groups was 0.5 and 6.87%, respectively, and the two groups had different risk for bleeding, with significant statistical difference, with RR values of 0.20 (95% CI 0.06–0.68, p = 0.01), which
Study (first author)
Design
Allocation Completeness concealment of follow-up
Baseline
Pan [9] Bryniarski [10] Hyams [11] Akman [12] Yang [13] Zhu [14] Xiao [15] Cao [16]
RCT RCT CCT CCT CCT CCT CCT CCT
NA yes NA NA NA NA NA NA
consistency consistency consistency consistency consistency consistency consistency consistency
reported reported reported reported reported reported reported reported
NA = Not available (insufficient information provided). Blinding: NA for all studies.
RIRS versus PCNL for Treatment of Renal Stones >2 cm
showed significant difference between the RIRS and the PCNL group. Three studies [9, 12, 16] provided data on other complications (deterioration of renal function and ureter steinstrasse). The pooled results showed that there was no significant difference between the RIRS and the PCNL group, with RR values of 1.18 (95% CI 0.47–2.95, p = 0.73) (fig. 5).
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Table 1. Quality evaluation of included studies
Study or subgroup (first author)
Experimental
Control
events
total
events
total
Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Hyams, 2009 [11] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13] Zhu, 2013 [14]
32 28 32 18 40 33 60 17
34 32 34 19 56 36 64 23
33 30 34 20 57 37 41 22
34 32 36 20 59 42 45 24
Weight, RR % M-H, random, 95% CI 16.4 11.5 15.2 12.8 10.5 12.3 15.6 5.8
0.97 (0.88, 1.07) 0.93 (0.80, 1.09) 1.00 (0.89, 1.12) 0.95 (0.82, 1.09) 0.74 (0.62, 0.88) 1.04 (0.90, 1.21) 1.03 (0.92, 1.15) 0.81 (0.61, 1.06)
Total (95% CI) 298 292 100.0 Total events 260 274 Heterogeneity: τ2 = 0.01, χ2 = 15.66, d.f. = 7 (p = 0.03), I2 = 55% Test for overall effect: Z = 1.45 (p = 0.15)
0.95 (0.88, 1.02)
RR M-H, random, 95% CI
0.5 0.7 1 1.5 2 Favors Favors experimental control
Fig. 2. Forest plot showing the stone-free rate between RIRS and PCNL.
Study (first author)
Year
Sample size (RIRS/PCNL)
Age (RIRS/PCNL)
Male:female (RIRS/PCNL)
Outcome measures
Pan [9]
2013
56/59
49.32 ± 13.7/ 49.37 ± 14.2
36:20/ 37:22
stone-free rate; operation time; hospital stay, complications
Bryniarski [10]
2012
32/32
53.4 ± 12.4/ 51.8 ± 11.8
15:17/ 16:16
stone-free rate; operation time; hospital stay, complications
Hyams [11]
2009
19/20
56/48
11:8/ 11:9
stone-free rate
Akman [12]
2012
34/34
44.5 ± 16.5/ 44.8 ± 17.1
18:16/ 16:18
stone-free rate; operation time; hospital stay, complications
Yang [13]
2013
64/45
21 – 73
71/38
stone-free rate; operation time; hospital stay, complications
Zhu [14]
2013
23/24
44.13 ± 7.11
NA
stone-free rate; operation time
Xiao [15]
2013
36/42
23 – 61/ 28 – 50
17:19/ 22:20
stone-free rate; operation time; hospital stay, complications
Cao [16]
2013
34/36
NA
NA
stone-free rate; operation time; hospital stay, complications
Discussion
Renal calculi are a very common illness having affected 5% of the population in the United States in the last 10 years [17], and recent studies have shown that the incidence of kidney stones in the United States and other 420
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parts of the world has increased [18]. Although the European Association of Urology (EAU) [19], the American Urological Association (AUA) [2] and the Japanese urolithiasis clinical guideline [20] recommended PCNL as the first method of choice for kidney stones >2 cm and also for complex renal stones. Compared with other proZheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Table 2. Basic characteristics of included studies
Study or subgroup (first author) Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13] Zhu, 2013 [14]
Experimental mean 58.2 85 58.2 73.07 146.94 117 68.22
Control
SD
total
mean
SD
total
13.4 17.6 13.4 13.5 13.06 36.5 9.32
34 32 34 56 36 64 23
38.7 100.1 38.7 62.39 101.95 90 44.32
11.6 29.9 11.6 10.6 10.3 18.2 10.34
34 32 36 59 42 45 24
Weight, % 14.6 13.0 14.6 14.9 14.7 13.5 14.7
Total (95% CI) 279 272 100.0 Heterogeneity: τ2 = 217.51, χ2 = 136.85, d.f. = 6 (p < 0.00001), I2 = 96% Test for overall effect: Z = 3.32 (p = 0.0009)
Mean difference IV, random, 95% CI
Mean difference IV, random, 95% CI
19.50 (13.54, 25.46) –15.10 (–27.12, –3.08) 19.50 (13.61, 25.39) 10.68 (6.23, 15.13) 44.99 (39.71, 50.27) 27.00 (16.58, 37.42) 23.90 (18.28, 29.52) 19.11 (7.83, 30.39) –200 –100 1 Favors experimental
100 200 Favors control
Fig. 3. Forest plot showing the mean operation time between RIRS and PCNL.
Study or subgroup (first author) Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13]
Experimental
Control
mean SD
total
mean SD
total
1.25 6.8 1.25 1.95 3.22 2.08
34 32 34 56 36 64
2.56 11.3 2.56 4.47 6.26 2.92
34 32 36 59 42 45
1.56 3.4 1.56 1.3 1.31 0.1
1.42 4.4 1.42 1.4 1.01 0.15
Weight, Mean difference % IV, random, 95% CI 17.2 10.9 17.2 18.0 17.9 18.8
–1.31 (–2.02, –0.60) –4.50 (–6.43, –2.57) –1.31 (–2.01, –0.61) –2.52 (–3.01, –2.03) –3.04 (–3.57, –2.51) –0.84 (–0.89, –0.79)
Total (95% CI) 256 248 100.0 Heterogeneity: τ2 = 1.34, χ2 = 126.11, d.f. = 5 (p < 0.00001), I2 = 96% Test for overall effect: Z = 4.18 (p < 0.0001)
–2.10 (–3.08, –1.11)
Mean difference IV, random, 95% CI
–20
–10 0 Favors experimental
10 20 Favors control
cedures, including extracorporeal shock wave lithotripsy, the high success rates of PCNL, exceeding 95%, have overshadowed its more invasive nature [21]. The global study showed that the major complications of PCNL, including blood transfusions (11.2–17.5%), urinary extravasation (7.2%) and high-grade fever, occurred in 32.1% of patients. Thanks to the recent advances in endoscopic procedures and equipments [22], flexible ureteroscopes with holmium laser lithotripsy have allowed a more efficient and safer treatment of stones through the natural orifice to reach all renal calyces since Marshall [23] first reported the use of flexible ureteroscopes. People then began to
deal with small kidney stones [24, 25]. A prospective comparative study come from India [26] showed that stone clearance in both modalities was high and complications were low in the mini-percutaneous and RIRS groups. Estrade et al. [27] recommended RIRS as a firstline treatment regardless of size and number of kidney stones if extracorporeal shock wave lithotripsy and PCNL are contraindicated or if their predictable results are poor (hard stones, morbid obesity, lower pole stones) or if stone access is difficult (intradiverticular). The latest digital ureteroscope has excellent image quality and easy handling, so urologists try to handle large stones. Several single-institution case series of RIRS for
RIRS versus PCNL for Treatment of Renal Stones >2 cm
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Fig. 4. Forest plot showing the hospital stay between RIRS and PCNL.
Study or subgroup (first author) 6.1.1. Fever Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Pan, 2013 [9] Xiao, 2013 [15] Yang, 2013 [13]
Experimental
Control
events
total
events
total
1 8 1 4 3 3
34 32 34 56 36 64
2 9 2 2 4 2
34 32 36 59 42 45
9.6 43.0 9.3 9.3 17.6 11.2
0.50 (0.05, 5.26) 0.89 (0.39, 2.01) 0.53 (0.05, 5.57) 2.11 (0.40, 11.05) 0.88 (0.21, 3.65) 1.05 (0.18, 6.06)
248
100.0
0.95 (0.54, 1.67)
34 32 36 42 45
16.8 33.5 16.3 21.7 11.8
0.20 (0.01, 4.02) 0.20 (0.02, 1.62) 0.21 (0.01, 4.25) 0.17 (0.01, 3.11) 0.24 (0.01, 5.66)
189
100.0
0.20 (0.06, 0.68)
34 36 59
12.8 24.9 62.3
2.00 (0.19, 21.03) 1.06 (0.16, 7.10) 1.05 (0.32, 3.44)
Subtotal (95% CI) 256 Total events 20 21 Heterogeneity: χ2 = 1.46, d.f. = 5 (p = 0.92), I2 = 0% Test for overall effect: Z = 0.18 (p = 0.85) 6.1.2. Bleeding Akman, 2012 [12] Bryniarski, 2012 [10] Cao, 2013 [16] Xiao, 2013 [15] Yang, 2013 [13]
0 1 0 0 0
34 32 34 36 64
2 5 2 3 1
Subtotal (95% CI) 200 Total events 1 13 Heterogeneity: χ2 = 0.03, d.f. = 4 (p = 1.00), I2 = 0% Test for overall effect: Z = 2.58 (p = 0.010) 6.1.3. Other Akman, 2012 [12] Cao, 2013 [16] Pan, 2013 [9]
2 2 5
34 34 56
1 2 5
Weight, RR % M-H, fixed, 95% CI
Subtotal (95% CI) 124 129 100.0 Total events 9 8 Heterogeneity: χ2 = 0.24, d.f. = 2 (p = 0.89), I2 = 0% Test for overall effect: Z = 0.35 (p = 0.73) Test for subgroup differences: χ2 = 5.96, d.f. = 2 (p = 0.05), I2 = 66.5%
RR M-H, fixed, 95% CI
1.18 (0.47, 2.95)
0.01
0.1 1 Favors experimental
10 Favors control
100
large renal stones have been reported [28–36]. In 1998, Grasso et al. [28] first reported 48 patients with upper urinary tract and minor staghorn calculi >2 cm who underwent RIRS, with an 81% (34 of 45 renal and 20 of 21 ureteral) stone-free rate in a single procedure. Second-stage procedures were carried out in 18 patients (8 of 15 large renal and 1 of 3 complex ureteral stone burdens), and the success rate increased to 94% without intraoperative complications. The study by El-Anany et al. [29] showed that stone fragmentation was achieved in only 23 (77%) patients because of poor visualization. In recent years, more and more doctors have been able to skillfully oper422
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ate the flexible ureteroscope and determine the efficacy of ureteroscopy as an alternative to PCNL to tackle large renal stones. RIRS had an average stone-free rate of around 91–97.5% for stones >2 cm, with an average number of procedures of no more than two [5, 30–35]. Takazawa et al. [6] reported that in kidney stones 2–4 cm in size, after three procedures the stone-free rate was up to 100% with no major intraoperative complications. Mariani [36] reported 16 patients with kidney stones >4 cm and a stone clearance rate of up to 88%. In our review, we found that the difference between the experimental and the control group regarding stone-free rate was not that dramatic in Zheng/Xiong/Wang/Luo/Zhang/Wei/ Wang
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Fig. 5. Forest plot showing the complications between RIRS and PCNL.
the respective included trial. Six studies [9–16] in this review showed that RIRS with holmium laser was as efficient as PCNL in the treatment of selected cases with larger renal stones. In order to improve the stone clearance rate, we can combine PCNL and flexible ureteroscopy for the treatment of large or complex renal stones [37, 38]. Flexible nephrolithotomy with a stone basket can easy reach each calyx, thus improving the stone clearance rate. RIRS with the small caliber ureteroscope is an endoscopic surgery through the natural orifice, thus renal parenchymal damage can be avoided. The overall complication rates have decreased, with major complication rates reported to be 2 cm with a high stone-free rate and significantly reduce hospital stay and bleeding without increasing complications. However, further randomized trials are needed to confirm these findings.
Disclosure Statement No competing financial interests exist.
1 Fernström I, Johannson B: Percutaneous pyelolithotomy. A new extraction technique. Scand J Urol Nephrol 1976;10:257–259. 2 Preminger GM, Assimos DG, Lingeman JE, et al: AUA guideline on management of staghorn calculi: diagnosis and treatment recommendations. J Urol 2005;173:1991–2000. 3 Scales CD Jr, Smith AC, Hanley JM, Saigal CS; Urologic Diseases in America Project: Prevalence of kidney stones in the United States. Eur Urol 2012;62:160–165. 4 Wiesenthal JD, Ghiculete D, D’A Honey RJ, Pace KT: A comparison of treatment modalities for renal calculi between 100 and 300 mm2: are shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy equivalent? J Endourol 2011;25:481–485. 5 Al-Qahtani SM, Gil-Deiz-de-Medina S, Traxer O: Predictors of clinical outcomes of flexible ureterorenoscopy with holmium laser for renal stone greater than 2 cm. Adv Urol 2012; 2012:543537.
RIRS versus PCNL for Treatment of Renal Stones >2 cm
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11 Hyams ES, Shah O: Percutaneous nephrostolithotomy versus flexible ureteroscopy/holmium laser lithotripsy: cost and outcome analysis. J Urol 2009;182:1012–1017. 12 Akman T, Binbay M, Ozgor F, et al: Comparison of percutaneous nephrolithotomy and retrograde flexible nephrolithotripsy for the management of 2–4 cm stones: a matchedpair analysis. BJU Int 2012;109:1384–1389. 13 Yang SX, Song C, Liu QL, et al: Management of renal calculi: retrograde ureteroscopic holmium laser versus percutaneous nephrolithotripsy. Chin J Urol 2013;34:666–669. 14 Zhu YS, Su HW, Deng QF: Comparative efficacy analysis of flexible ureteroscopic lithotripsy and percutaneous nephrolithotomy for treatment of renal calyceal stones. J Luzhou Med Coll 2013;4:382–383. 15 Xiao KB, Liu XL, Zang YC, et al: Comparative efficacy analysis of percutaneous nephrolithotomy and flexible ureteroscopic lithotripsy for treatment of kidney stones. Jiangsu Med J 2013;11:1136–1137.
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