Comparison of Holmium: YAG Laser and Pneumatic Lithotripsy in the Treatment of Ureteral Stones: An Update Meta-Analysis

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1 Urologia Internationalis Urol Int 7;98: DOI:.59/44869 Received: April 8, 6 Accepted: July 9, 6 Published online: August, 6 Shulian Chen Liang Zhou Tangqiang Wei Deyi Luo Tao Jin Hong Li Kunjie Wang Comparison of Holmium: YAG Laser and Pneumatic Lithotripsy in the Treatment of Ureteral Stones: An Update Meta-Analysis Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, PR China Key Words Ureteral calculi Laser lithotripsy Pneumatic lithotripsy Abstract Purpose: Holmium YAG laser lithotripsy () and pneumatic lithotripsy () are the most commonly used procedures in the treatment of ureteral calculi. In a previous meta-analysis examining the treatment effect of the modalities, the authors highlighted the need for large sample size and high quality trials to provide more uncovered outcome. Recently, several randomized controlled trials (RCTs) evaluating the same issue with larger patient number and more complicated data have been published. Therefore, we conducted this meta-analysis to update and synthesize evidence on the efficacy and safety of the procedures in the treatment of ureteral calculi. Methods: The relevant studies were identified by searching Medline, EMBASE and Cochrane Library Database from January 99 to November 5. RCTs assessing the efficacy and safety of Holmium YAG laser and for ureteral stones were included. Two reviewers independently screened studies and extracted data. Results: A total of 8 studies were identified including,555 patients. Compared with, Holmium YAG significantly reduced the mean op- erative time (weighted mean difference =.5, 95% CI 7.6 to 5.99, p <.) and increased the early stonefree rate (OR.69, 95% CI.9.78, p <.) and the delayed stone-free rate (OR., 95% CI.., p =.4). However, a higher postoperative ureteral stricture rate (OR.8, 95% CI. 7., p =.) was observed in group over group. There was no statistical significance in the ureteral perforation rate (OR.9, 95% CI.65.6, p =.58), the stone migration rate (OR.64, 95% CI.4., p =.5), the postoperative gross hematuria rate (OR.7, 95% CI.., p =.) and the postoperative fever rate (OR.7, 95% CI.5.9, p =.). Conclusions: Our data reconfirmed that Holmium for ureteral stones can achieve shorter mean operative time, better early and delayed stonefree rate with larger sample size and more high quality studies. And further trials are unlikely to considerably alter this conclusion. In terms of higher risk of postoperative ureteral stricture in group over group observed in our review, more high quality, multicenter RCTs with long-term followup outcome are warranted to better assess this issue. S.C. and L.Z. contributed equally to this work. 6 S. Karger AG, Basel karger@karger.com 6 S. Karger AG, Basel Kunjie Wang Department of Urology Institute of Urology, West China Hospital, Sichuan University Guo Xue Xiang 7, Chengdu, Sichuan 64 (China) scu.edu.cn /6/7 4::47 PM

2 Introduction Over the past decades, treatments for ureteral calculi evolve from open ureterolithotomy to minimally invasive procedures, including extracorporeal shock wave lithotripsy, ureteroscopic lithotripsy and laparoscopic lithotomy []. Among them, ureteroscopic lithotripsy holds the minimal contraindications, nearly available for all except severe ureteral stricture preventing successful scope passage []. Together with high stone-free rate and relatively low complications, ureteroscopic interventions become the main therapeutic way for large ureteral stones with indications in many academic centers. In the process of ureteroscopic lithotripsy, electrohydraulic, ultrasonic, pneumatic and laser lithotripters are available. Amid them, Holmium YAG laser lithotripsy () and pneumatic lithotripsy () are the predominant procedures []. There is a trend in favor of using, owing to advantages on fragmentation and flexibility [4]. However, other authors thought that was comparable to in fragmentation efficiency, accompanying the advantage of low cost and easy installation [5]. Over the past decade, data comparing the efficacy and safety of and are inconclusive [5 7]. In, a meta-analysis by Yin et al. [8], which included 4 trials and 95 patients, up to, concluded that had a higher stone-free rate, a lower migration and retaining JJ catheter rate when compared with. It has been recommended that was a powerful, effective and safe technique for distal ureteral stones. Since, there haves been randomized controlled trials (RCTs) that were published with much more sample size and information on complications. And another RCT evaluating the same issue published in 8 by Manohar et al. [7] was identified through systematic search. When comparing the efficacy and safety of and, a relatively small patient number and loss of useful data in many included studies weakened the validation of the results in the review by Yin et al. [8]. In the light of this, we conducted this updated metaanalysis in an effort to reveal a wealth of evidence and provide more valid information for clinical practice. Methods Literature Search and Study Selection We searched the databases Medline, EMBASE and the Cochrane Library from January, 99, to November 5. The key words of search strategy are composed of ureteral calculi, laser lithotripsy, pneumatic lithotripsy (and multiple synonyms for each term). Relevant trials in the reference lists were also searched. The potentially eligible studies were screened by authors (S.C. and L.Z.) independently. Inclusion Criteria and Exclusion Criteria Inclusion criteria were as follows: () RCT design of patients with ureteral stones; () studies comparing treatment of and for ureteral calculi; () English language; (4) only studies on humans; and (5) eligible trials that measured at least one of the following outcomes: mean operative time, early stone-free rate, delayed stone-free rate, stone migration rate, ureteral perforation, postoperative gross hematuria, postoperative fever and postoperative ureteral stricture. Exclusion criteria are as follows: () patients of children; () comparative studies or cases series; and () patients with renal insufficiency, abnormal anatomy, associated renal stones, active kidney infection and active bleeding disorders. Controversial trials were settled by consensus. Data Extraction and Outcomes of Interest Primary information, including mean ± SDs, OR and 95% CI, was extracted directly from articles by investigators independently. Additional data were extracted from the studies, including the first author, year of publication, sample size and other clinical characteristics. The main concerned outcomes included mean operative time, stone migration rate, early stone-free rate (assessment within month postoperation), delayed stone-free rate (assessment from to months postoperation), ureteral perforation rate, postoperative gross hematuria rate, postoperative fever and postoperative ureteral stricture rate. Study Quality and Level of Evidence The quality of these eligible citations was assessed using the Cochrane handbook, which was independently graded by reviewers (S.C. and L.Z.). Quality assessment checklist consisted of the following items: the details of randomization, allocation concealment, blinding of investigators, participants, outcome assessors, intention to treat analysis, selective outcome report, completeness of follow-up and comparable basic characteristics. On the basis of above items, studies were divided into categories as follows: () all quality components adequate low risk of bias; () one or more of the quality components unclear moderate risk of bias; and () one or more of the quality components inadequate high risk of bias. Statistical Analysis The Manager 5. software (The Cochrane Collaboration, Oxford, UK) statistical package was used to analyze the ORs for dichotomous variables and the mean differences for continuous variables as well as 95% CI. The proportion of heterogeneity across the studies was tested using the χ and the I index (range %). If significant heterogeneity was found (p <. and I = 5%), we performed subgroup analysis or sensitivity test. If the heterogeneity still existed, the random effects model was adopted. Otherwise, we used a fixed effects model with the Mantel Haenszel method to calculate the pooled OR. All p values were two-tailed and p <.5 was considered statistically significant. Begg s test was used in a funnel plot of log OR against its SE to assess publication bias, and Egger s unweighted regression asymmetry test was used to detect the degree of asymmetry [9, ]. 6 Urol Int 7;98: DOI:.59/44869 Chen/Zhou/Wei/Luo/Jin/Li/Wang /6/7 4::47 PM

3 Records identified through database searching (n = 7) Additional records identified through other sources (n = ) Records after duplicates removed (n = 9) Records screened (n = 9) s, irrelevant articles excluded (n = ) Full-text article assessed for eligibility (n = 8) Full articles excluded because not RCT, meta-analysis, study is not about research question (n = ) Studies included in qualitative synthesis (n = 8) Fig.. Flowchart of study selection for the meta-analysis. Studies included in qualitative synthesis (meta-analysis) (n = 8) Table. Quality assessment of included studies Author Randomization Allocation concealment Blinding ITT analysis Completeness of follow-up Basic line comparable Selective outcome report Quality level Li et al. [] Yes Unclear Unclear Yes Yes Yes No B Cimino et al. [] Yes Yes Single Yes Yes Yes No A Razzaghi et al. [] Yes Yes Unclear Yes Yes Yes No B Kassem et al. [] Yes Unclear Unclear Yes Yes Yes No B Binbay et al. [4] Yes Unclear Unclear Yes Yes Yes No B Garg et al. [5] Yes Yes Unclear Yes Yes Yes No B Maghsoudi et al. [6] Yes Unclear Unclear Yes Yes Yes No B Manohar et al. [7] Yes Yes Unclear Yes Yes Yes No B Results Methodological Quality and Baseline Characteristics Figure shows the process of study selection. All included 8 studies were randomized controlled studies published in 8 5 [, 7, 6] ( table ). According to Cochrane handbook, study was graded as A and 7 studies were graded as B ( table ). The standard format should be comprised of the following sections: () general information about the study, including the authors, publication year, interval of time in which the subjects were enrolled, total number of patients, nationality of the study, gender and age (range and mean); () inclusion and exclusion criteria, stone location and stone diameter; () type of surgical procedure and stone fragmentation device, antibiotic prophylaxis and time of the surgical procedure; and (4) early stone-free rate, delayed stone-free rate, ureteral perforation rate, stone migration rate and number and type of other complications. Overall, the baseline Holmium: YAG versus Urol Int 7;98: 7 DOI:.59/ /6/7 4::47 PM

4 Study or Subgroup Binbay, Kassem, Cimino, 4 Li, 5 Mean SD Mean SD Weight %.8%.4% 7.% Mean difference IV, Random, 95% CI 8. [.78,.] 9. [.58,.58]. [ 9.5, 7.5]. [ 4.7,.6] 4 5 Mean difference IV, Random, 95% CI (95% CI) 6 66.%.5 [ 7.6, 5.99] Heterogeneity: Tau =.95; Chi =.5, df = (p =.6); I = 76% Test for overall effect: Z = 4.8 (p <.) 5 5 Fig.. Comparison of vs. on the mean operative time. Table. Characteristics of included studies Author Groups Number Age of patients Mean stone size Follow-up, months MOT ESFR DSFR MP 4 GH 5 UP 6 US 7 PS 8 Li et al. [] ±7.5 8± ±6. 4± Cimino et al. [] ±.5 6± NR 86.7 NR 4 5.±.4 6± NR NR Razzaghi et al. [] 5.9.7±4.5.7±.6 NR 6.4±.5 ± ± NR Kassem et al. [] 4.9±5.8.8±4 44.5± NR NR 46.±.9.±.7 5.5± NR NR Binbay et al. [4].±6.4.7± days ± NR NR 9.6± ±58. 8 days 48±.4 8 NR 4 NR Garg et al. [5] ±..±.9 8 days 4.± NR 7 NR 4±4..±.6 8 days 9.8 ± NR 4 6 NR Maghsoudi et al. [6] ±4.6.7±. NR NR 95. NR NR NR.5±5.5.±.8 NR NR 8.5 NR NR NR Manohar et al. [7] ± ± ±7.58* NR NR 7.6±.8.7± ±.* NR 88 4 NR Mean operative time (min); early stone-free rate; delayed stone-free rate; 4 migration patients; 5 gross hematuria; 6 ureteral perforation; 7 ureteral stricture; 8 postoperative fever. * Fragmentation time. NR = Not report. characteristics of the 8 included trials were comparable. ly,,555 objects were incorporated in this meta-analysis. Outcomes Mean Operative Time All studies, aside from Maghsoudi et al. [6], unequivocally compared the mean operative time. We excluded studies by the Manohar et al. [7], Garg et al. [5] and Razzaghi et al. [] because they only counted the lithotripsy time. High level of heterogeneity was detected among the studies (I = 76%). Without finding the sources of heterogeneity by a sensitivity analysis, we applied the random effects model. The result showed that there was a significant difference between the groups, the mean operative time of was much shorter than that of group (weighted mean difference =.5, 95% CI 7.6 to 5.99, p <.; fig. ). 8 Urol Int 7;98: DOI:.59/44869 Chen/Zhou/Wei/Luo/Jin/Li/Wang /6/7 4::47 PM

5 Garg, 9 Binbay, Kassem, Razzagh, Li, Weight %.9% 4.9%.% 8.6% 6.9 [.66, 6.5] 9.75 [.6, 8.]. [.,.99].5 [.46, 447.9].49 [.69,.66] 9 5 (95% CI) events 6 56 Heterogeneity: Chi = 7.6, df = 4 (p =.); I = 47% Test for overall effect: Z = 5.66 (p <.).%.69 [.9,.78].. Fig.. Comparison of vs. on the early stone-free rate. Weight Manohar, 8 Maghsoudi, 8 Kassem, Razzaghi, Cimino, 4 Li, % 5.% 5.%.4% 9.7%.7%.7 [.4,.59] 4.7 [.94,.8].5 [.6, 7.74] 7. [.95, 7.46].55 [.58, 4.].88 [.7,.] (95% CI) events Heterogeneity: Chi = 5.5, df = 5 (p =.5); I = % Test for overall effect: Z =.5 (p =.4).%. [.,.].. Fig. 4. Comparison of vs. on the delayed stone-free rate. Early Stone-Free Rate Except Cimino et al. [], Maghsoudi et al. [6] and Manohar et al. [7] assessing stone-free rate later than month post operation, all the other trials reported information on early stone-free rate. The results showed improved an early stone-free rate than (OR.69, 95% CI.9.78, p =.; fig. ). Delayed Stone-Free Rate Six studies included data about the delayed stone-free rate. With regard to this item, these mixed studies presented high homogeneity, as indicated by the figure 4. So, the fixed effects model was applied, showing that generated a higher delayed stone-free rate than (OR., 95% CI.., p =.4; fig. 4 ). Stone Migration Rate Six trials conducted comparison on this item. Because of homogeneity across these studies (p =., I = 8%), the fixed effects model was carried out to integrate data. In terms of stone migration rate, no significance was detected among the groups (OR.64, 95% CI.4., p =.5; fig. 5 ). Ureteral Perforation Rate All studies provided information on this item, of which were not estimable on the OR. No obvious heterogeneity existed and we used the fixed effects model. The result suggested there was no significance between and in relation to ureteral perforation rate (OR.9, 95% CI.65.6, p =.58; fig. 6 ). Holmium: YAG versus Urol Int 7;98: 9 DOI:.59/ /6/7 4::47 PM

6 Manohar, 8 Maghsoudi, 8 Garg, 9 Binbay, Kassem, Li, Weight 6.% 6.%.% 8.%.8% 47.9%.66 [.4, 6.78]. [.,.6].8 [.,.5]. [.,.6]. [.,.6].86 [.47,.] (95% CI) events 4 5 Heterogeneity: Chi = 6.99, df = 5 (p =.); I = 8% Test for overall effect: Z =.97 (p =.5).%.64 [.4,.].. Favours (experimental) Favours (control) Fig. 5. Comparison of vs. on the stone migration rate. Weight Binbay, Cimino, 4 Garg, 9 Kassem, Li, 5 Maghsoudi, 8 Manohar, 8 Razzaghi, % 5.%.6% 9.4% 64.% 4.%.5 [.8,.59].95 [.6, 5.54].59 [., 66.49].54 [.4, 9.75].5 [.54,.44] Not estimable.64 [., 4.9] Not estimable (95% CI) 78 events 4 Heterogeneity: Chi =.94, df = 5 (p =.97); I = % Test for overall effect: Z =. (p =.58) 77.%.9 [.65,.6].. Fig. 6. Comparison of vs. on the ureteral perforation rate. Postoperative Gross Hematuria Rate Five studies carried out the comparison on postoperative gross hematuria. Owing to heterogeneity (p =.8, I = %) of the included studies, we employed the random effects model. The result suggested that, with respect to this outcome, there was no significant difference between group and group (OR.8, 95% CI.4.94, p =.88; fig. 7 ). Postoperative Ureteral Stricture Rate Six trials presented information on postoperative ureteral stricture. A correspondingly high level of homogeneity was detected. resulted in more postoperative ureteral stricture than when tested for overall effect (OR.8, 95% CI. 7., p =.; fig. 8 ). Postoperative Fever Rate Three studies showed data on postoperative fever rate. High homogeneity existed, and we adopted the fixed effects model. As a result, there were no significant difference between and group in this item (OR.7, 95% CI.5.9, p =.; fig. 9 ). Discussion Summary of Main Findings The aim of this systematic review was to integrate the current evidence for evaluating the effect of and in the treatment of ureteral calculi. The overall results of this meta-analysis indicate a trend favoring as the first Urol Int 7;98: DOI:.59/44869 Chen/Zhou/Wei/Luo/Jin/Li/Wang /6/7 4::47 PM

7 Manohar, 8 Garg, 9 Binbay, Razzaghi, Li, Weight.5% 7.%.4% 8.8% M-H, Random, 95% CI 6.47 [., 4.].96 [.8,.6]. [.,.8] Not estimable.7 [.6,.7] M-H, Random, 95% CI (95% CI) % events Heterogeneity: Tau =.55; Chi = 6.8, df = (p =.8); I = % Test for overall effect: Z =.6 (p =.88).8 [.,.94].. Fig. 7. Comparison of vs. on the postoperative gross hematuria rate. Weight Manohar, 8 Garg, 9 Binbay, Kassem, Cimino, 4 Li, % 7.9% 5.8%.%.8% Not estimable.59 [., 66.49]. [., 8.].8 [., 77.8].95 [.6, 5.54] 4.95 [.87,.9] (95% CI) events 7 7 Heterogeneity: Chi =.4, df = 4 (p =.49); I = % Test for overall effect: Z =.9 (p =.).%.8 [., 7.].. Fig. 8. Comparison of vs. on the postoperative ureteral stricture rate. Weight Razzaghi, Cimino, 4 Li, % 4.9% 9.8%.49 [.4, 5.].9 [.7, 6.].7 [.47,.8] 4 5 (95% CI) 69 6 events Heterogeneity: Chi =.6, df = (p =.7); I = % Test for overall effect: Z =.54 (p =.).%.7 [.5,.9].. Fig. 9. Comparison of vs. on the postoperative fever rate. choice for ureteral stones as is recommended by the European Association of Urology, that Holmium YAG laser is the most effective lithotripsy system, which has become the gold standard for ureteroscopy and flexible nephroscopy [7]. When compared with, shorter mean operative time, higher early and delayed stone-free rate were found in the group, without significant difference in terms of stone migration rate, ureteral perforation rate, postoperative gross hematuria rate and postoperative fever rate. Any reduction in favor of was post- Holmium: YAG versus Urol Int 7;98: DOI:.59/ /6/7 4::47 PM

8 operative ureteral stricture rate. However, this result was mainly driven by the study by Li et al. [], which reported much more postoperative ureteral stricture patients (n = 9) than the other studies (n = 5). However, postoperative ureteral stricture could be due to factors associated with surgical technique, rate of impaction and chronicity of stone presence that were not explicitly reported in their trial. Consequently, though with high homogeneity, caution should be exercised to interpret the result. Limitations of Included Studies This is a pooled study including 8 RCTs assessing the effect of modalities for the treatment of ureteral calculi. High to moderate heterogeneity exited. I score for mean operative time rate, postoperative gross hematuria rate and early stone-free rate were 76, and 47%, respectively. The high heterogeneity might be attributed to the following reasons: () included trials incorporated different segment ureteral stones 5 studies [,, 4 6] including proximal, middle, distal ureteral stones; studies [, ] including middle and distal ureteral stones; and study [7] including upper ureteral stones only. As proximal ureteral stones are more difficult for ureteroscopic lithotripsy, mean operative time should be longer than that of middle and distal ureteral stones. Whilst data of mean operative time were not provided separately according to the stone position, subgroup analysis could not be made correspondingly. () Various pulse energy and frequencies were applied by different surgeons in the process of operation. Most trials employed.8.5 J energy in frequency of 5 5 Hz. Two studies [, ] with a relatively low energy setting (.5 J and.6. J) showed longer mean operation time. According to the research of Kronenberg and Traxer [8] and Wezel et al. [9], pulse energy was an essential variable affecting fragmentation efficiency. However, all studies presented a range of lithotripsy energy and frequencies, which were overlapped among each other, and made it impossible to exercise subgroup analysis. () A wide variation of familiarity with the types of lithotripter between the operators might cause the high heterogeneity. Although some differences existed in the included studies, high homogeneity was generated in terms of delayed stone-free rate, ureteral perforation rate and postoperative fever rate to confirm the validation of these results. Limitations of This In order to minimize bias within this review, we performed an extensive literature search, and reviewers independently screened the full texts for inclusion and extracted the data. However, without any attempt to source unpublished data from thesis and conference proceedings abstracts and articles in any other language than English, bias might be introduced. This method has also been questioned by some authors who claimed that truly unpublished studies frequently have poor methodology, and ones with better methodology often eventually become published []. So, it is impossible to know if it is truly a limitation or if there are unpublished studies considerable enough to alter our conclusions. Comparison with the Previous The aim of the meta-analysis by Yin et al. [8] was to compare the effect of the techniques in the treatment of distal ureteral stones, but their study was composed of very small sample size and mixed proximal ureteral stones with distal ureteral stones. Our review further included more ureteral stone patients in different ureteral segments and elevated treatment target from distal to total ureter. Our main findings differ very little from the review; however, more robust conclusions about the effect of the procedures can be drawn from our review. And a higher postoperative ureteral stricture rate was found in the group. Conclusions This study generally compared the efficacy and safety of and for the treatment of ureteral stones. Our review reconfirmed the result that, at the aspect of mean operative time, early and delayed stone-free rate, is superior to. And further studies are unlikely to considerably alter this conclusion. A higher risk of postoperative ureteral stricture for patients was also observed in our meta-analysis. However, more high quality, multicenter RCTs with long-term follow-up outcome are warranted to better assess this issue. Acknowledgments This work was supported by the National Natural Science Foundation of China (grant Nos. 795 and 84797), the National Science Foundation for Young Scholars of China (grant No. 89). Disclosure Statement No competing financial interests exist. Urol Int 7;98: DOI:.59/44869 Chen/Zhou/Wei/Luo/Jin/Li/Wang /6/7 4::47 PM

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