Reviewers' comments:
Reviewer #1:
The 8 authors used a Piezolith 3000 for the treatment of ureter stones and seem to have excellent knowledge of ESWL. Target of this study was to define criteria to avoid unsuccessful primary ESWL for ureter stones in order to save time and costs for the patients. 90 patients with ureter stones were treated with ESWL and after 3 months evaluated in regard to stone-free rate: 50 of these patients required a URS during follow-up.The authors found legitimate and well known problems of primary ESWL stone clearance in obese patients who have been treated in a rotated side position (the authors should mention the penetration depth of the used Piezolith), in impacted stones and severe hydronephrosis and in radio opaque stones.
à We added the depth of penetration of this lithotripter in the Material and Methods of the revised manuscript. “The depth of penetration of this lithotripter can be adjusted continuously form 0 to 165mm.”
The authors should discuss the limitations of ESWL treatment in stones > 1cm and if this maybe due to the lower energy output of the Piezolith.à We totally agree with your opinion. The low energy density of this piezoelectric lithotripter can affect success rate in larger stone. We added this to the limitation part of revised manuscript.
“In addition, there is an issue about the characteristics of piezoelectric lithotripter. One of the advantages of this lithotripter is anesthetic-free treatment due to the relatively low energy density at the skin entry point of the shockwave [22]. However the low energy density can hampers its ability to effectively break urinary stones [22]. Therefore, the success rate of larger stone can be influenced by the type of lithotripter in this study. The results of this study cannot be generalized to all types of lithotripter. Also, this is retrospective study. The setting of ESWL in this study was different from those reported as more effect in recent studies. In recent studies, 60 pulse rates is more effect than higher pulse rates [23].”
There is no argument against this work because it is a careful summing up of already well known facts.It would be helpful if the authors would describe the outcome of the 50 URS in regards to success rate and side effects.
à The stones of these 50 patients were successfully removed by URS treatment. We added this to the results part of the revised manuscript. Unfortunately we cannot access to information of the side effect of URS treatment in these patients
In such an extensive statistical work-up it should also be possible to compare the differences in the performance of different operators or surgeons.à Our procedure was done by one urologist. Therefore we cannot compare the differences in the performance of different operators or surgeons. We added this to the revised manuscript. “The ESWL treatment was performed or supervised by same urologist (S.I. J) in all patients.”
The argument to treat certain stones primarily with URS / LASER is definitely consequent in the described cases. However, it should at least be discussed that this cannot be generalized because it depends in a high degree on the used Lithotriper and the expertise of each of the surgeons.à We agree with your opinion. This study was done only by piezoelectric lithotripter and by one surgeon. Therefore the results of the study cannot be generalized. In revised manuscript, we added this to the limitation and we also change the Title of the article.
Before revision (title): Factors influencing the failure of extracorporeal shock wave lithotripsy in the management of solitary ureteral stone
After revision (title): Factors influencing the failure of extracorporeal shock wave lithotripsy with Piezolith 3000 in the management of solitary ureteral stone
In limitation part of revised manuscript:
“In addition, there is an issue about the characteristics of piezoelectric lithotripter. One of the advantages of this lithotripter is anesthetic-free treatment due to the relatively low energy density at the skin entry point of the shockwave [22]. However the low energy density can hampers its ability to effectively break urinary stones [22]. Therefore, the success rate of larger stone can be influenced by the type of lithotripter in this study. The results of this study cannot be generalized to all types of lithotripter. Also, this is retrospective study. The setting of ESWL in this study was different from those reported as more effect in recent studies. In recent studies, 60 pulse rates is more effect than higher pulse rates [23].”
There are a few formal comments:Page 2: line 15: excluded were stones size < 3mm (!) (confusion of <with>)
à I revised manuscript.
Before revision: “size > 3mm, solitary stones and no evidence of urinary tract infection or acute renal failure.” After revision: “uncorrected coagulopathy and anticoagulated cases, and multiple stones on the ipsilateral side.”
Page 3: line 1: "a max. of 3,000 SW at frequency 120 were applied"Total energy is quite low in their settings and the frequency is too high. This has to be discussed by the authors.
à We added the detail of procedure in revised manuscript. The procedure was done as manual of the manufacturer of Piezolith 3000. We used the energy level of 0.91 to 1.08mJ/mm2. This is usual setting in our country [Oh BS et al. Korean J Urol 2005;46:1278-1283][Choi NY et al. Korean J Urol 2008;49:150-154].
We totally agree with your opinion that the frequency of our study is too high. Recent review article published, 60 pulse rates is superior to higher pulse rates [Rassweiler JJ et al. Eur Urol 2011;59:784-796]. Unfortunately, this is retrospective study started from year 2006. We changed our setting of procedure recently. All of enrolled cases were done by old setting. We added this to limitations.
In material and method part of revised manuscript: “A maximum of 3,000 shockwaves were delivered to a maximal power of 89 to 102 MPa and energy of 0.91 to 1.08 mJ/mm2 at 120 shocks/min during one session.”
In discussion of revised manuscript: “Also, this is retrospective study. The setting of ESWL in this study was different from those reported as more effect in recent studies. In recent studies, 60 pulse rates is more effect than higher pulse rates [23].”
Reviewer #2:
These results are only true for the type of lithotripter used, would you agree?à We agree with your opinion. Therefore we changed the title by adding Piezolith 3000. Also, we added this to the limitation part.
Before revision (title): Factors influencing the failure of extracorporeal shock wave lithotripsy in the management of solitary ureteral stone
After revision (title): Factors influencing the failure of extracorporeal shock wave lithotripsy with Piezolith 3000 in the management of solitary ureteral stone
In limitation part of revised manuscript:
“In addition, there is an issue about the characteristics of piezoelectric lithotripter. One of the advantages of this lithotripter is anesthetic-free treatment due to the relatively low energy density at the skin entry point of the shockwave [22]. However the low energy density can hampers its ability to effectively break urinary stones [22]. Therefore, the success rate of larger stone can be influenced by the type of lithotripter in this study. The results of this study cannot be generalized to all types of lithotripter. Also, this is retrospective study. The setting of ESWL in this study was different from those reported as more effect in recent studies. In recent studies, 60 pulse rates is more effect than higher pulse rates [23].”
How have the results of this study influenced your current strategy of treatment of ureteral stones?à After our study, we used URS at first procedure with stone size stone size ≥1 cm and severe hydronephrosis.