Chang TH. et al., 2020: Comparison of ultrasound-assisted and pure fluoroscopy-guided extracorporeal shockwave lithotripsy for renal stones

Wednesday, 10 March 2021

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Chang TH, Lin WR, Tsai WK, Chiang PK, Chen M, Tseng JS, Chiu AW.
Department of Urology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan N. Rd., Taipei City, 10449, Taiwan.
2Department of Urology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan N. Rd., Taipei City, 10449, Taiwan.
3Mackay Medical College, No.46, Sec. 3, Zhongzheng Rd., Sanzhi Dist., New Taipei City, 252, Taiwan.
Mackay Junior College of Medicine, Beitou District, Nursing, and Management, No.92, Shengjing Road, Taipei City, 11272, Taiwan.
Department of Urology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan N. Rd., Taipei City, 10449, Taiwan.
School of Medicine, National Yang-Ming University, No.145, Zhengzhou Rd., Datong Dist., Taipei City, 10341, Taiwan.

Abstract

Background: In this study, we aimed to compare the efficacy and clinical outcomes of shock wave lithotripsy (SWL) for patients with renal stones using pure fluoroscopy (FS) or ultrasound-assisted (USa) localization with two lithotripters.

Methods: We retrospectively identified 425 patients with renal calculi who underwent SWL with either a LiteMed LM-9200 ELMA lithotripter (209 cases), which combined ultrasound and fluoroscopic stone targeting or a Medispec EM-1000 lithotripter machine (216 cases), which used fluoroscopy for stone localization and tracking. The patient demographic data, stone-free rates, stone disintegration rates, retreatment rates and complication rates were analyzed.

Results: The USa group had a significantly higher overall stone-free rate (43.6 vs. 28.2%, p < 0.001) and stone disintegration rate (85.6 vs. 64.3%, p < 0.001), as well as a significantly lower retreatment rate (14.8 vs. 35.6%, p < 0.001) and complication rate (1.9 vs. 5.5%, p = 0.031) compared with the FS group. This superiority remained significant in the stone size < 1 cm stratified group. In the stone size > 1 cm group, the stone-free rate (32.4 vs. 17.8%, p = 0.028), disintegration rate (89.2 vs. 54.8%, p = 0.031) and retreatment rate (21.6 vs. 53.4%, p < 0.001) were still significantly better in the USa group, however there was no significant difference in the complication rate. The most common complication was post-SWL-related flank pain.

Conclusion: SWL is a safe and non-invasive way of treating renal stones. This study compared two electromagnetic shock wave machines with different stone tracking systems. LiteMed LM-9200 ELMA lithotripter, which combined ultrasound and fluoroscopic stone targeting outperformed Medispec EM-1000 lithotripter, which used fluoroscopy for stone localization and tracking, with better stone-free rates and disintegration rates, as well as lower retreatment rates and complications with possible reduced radiation exposure.
BMC Urol. 2020 Nov 10;20(1):183. doi: 10.1186/s12894-020-00756-6. PMID: 33172476. FREE ARTICLE

Comments 1

Hans-Göran Tiselius on Wednesday, 10 March 2021 09:30

There are several factors that determine the outcome of SWL:
1.Stone size
2. Stone composition (hardness)
3. Stone location
4. Intrarenal anatomy
5. Skin-stone-distance (SSD)
4. Shockwave energy
6. Ramping strategy
7. Shockwave hit rate
8. Patient positioning
9. How trauma to adjacent organs can be avoided
10. Respiratory movements
11. Obstacles in the shockwave path
12. Patient’s age
13. BMI
14. Pain treatment
15. Patient’s tolerance
16. Take care to avoid infection and bleeding complications
17. Operator’s experience and expertise
Moreover, it is essential to
18. Avoid excessive radiation

In the current article the authors report the experience of ultrasound (US)-tracking by comparing the results of SWL between two lithotripters. One in which only fluoroscopy was available and one in which fluoroscopy was assisted by an US tracking system.
The conclusion was that with US stone tracking the stone free rates were better than when fluoroscopy was used alone. The interval between successive position and progress control was 600 shockwaves. This is in my mind a relatively long interval and it is not mentioned in the article to which extent the focusing had to be adjusted at these controls or not. But it can be assumed that the hit-rate with the continuous US-tracking system was superior to that achieved when only fluoroscopy was used. Unfortunately, the fluoroscopy times were not reported.
I have no experience with the two lithotripters used in this comparison: LM-9200 ELMA and EM-1000, but the authors describe them as low-frequency lithotripters.

The results in this report are highly interesting and it is desirable to use US more commonly with SWL to reduce the x-ray dose. It is, however, difficult to correctly interpret the ultrasound image compared with the fluoroscopic image and it is possible that AI can be a useful assistant for the further development of this step. When the learning threshold is passed, there are some other requirements that are necessary for making US-tracking attractive and effective. The equipment must be maximally user friendly, allow for automatic tracking and enable remote control.
Reference.
Chang CC et al. In vitro study of the revised ultrasound based real time tracking of renal stones for shock wave lithotripsy. Part 1. J Urol 2013;189:2357-2363. DOI:10.1016/j.juro.2012.11.111

Hans-Göran Tiselius

In the current article the authors report the experience of ultrasound (US)-tracking by comparing the results of SWL between two lithotripters. One in which only fluoroscopy was available and one in which fluoroscopy was assisted by an US tracking system.
The conclusion was that with US stone tracking the stone free rates were better than when fluoroscopy was used alone. The interval between successive position and progress control was 600 shockwaves. This is in my mind a relatively long interval and it is not mentioned in the article to which extent the focusing had to be adjusted at these controls or not. But it can be assumed that the hit-rate with the continuous US-tracking system was superior to that achieved when only fluoroscopy was used. Unfortunately, the fluoroscopy times were not reported.
I have no experience with the two lithotripters used in this comparison: LM-9200 ELMA and EM-1000, but the authors describe them as low-frequency lithotripters.

[img]https://www.storzmedical.com/images/blog/ChangTH.JPG[/img]

The results in this report are highly interesting and it is desirable to use US more commonly with SWL to reduce the x-ray dose. It is, however, difficult to correctly interpret the ultrasound image compared with the fluoroscopic image and it is possible that AI can be a useful assistant for the further development of this step. When the learning threshold is passed, there are some other requirements that are necessary for making US-tracking attractive and effective. The equipment must be maximally user friendly, allow for automatic tracking and enable remote control.
Reference.
Chang CC et al. In vitro study of the revised ultrasound based real time tracking of renal stones for shock wave lithotripsy. Part 1.  J Urol 2013;189:2357-2363. DOI:10.1016/j.juro.2012.11.111

Hans-Göran Tiselius

There are several factors that determine the outcome of SWL: 1.Stone size 2. Stone composition (hardness) 3. Stone location 4. Intrarenal anatomy 5. Skin-stone-distance (SSD) 4. Shockwave energy 6. Ramping strategy 7. Shockwave hit rate 8. Patient positioning 9. How trauma to adjacent organs can be avoided 10. Respiratory movements 11. Obstacles in the shockwave path 12. Patient’s age 13. BMI 14. Pain treatment 15. Patient’s tolerance 16. Take care to avoid infection and bleeding complications 17. Operator’s experience and expertise Moreover, it is essential to 18. Avoid excessive radiation In the current article the authors report the experience of ultrasound (US)-tracking by comparing the results of SWL between two lithotripters. One in which only fluoroscopy was available and one in which fluoroscopy was assisted by an US tracking system. The conclusion was that with US stone tracking the stone free rates were better than when fluoroscopy was used alone. The interval between successive position and progress control was 600 shockwaves. This is in my mind a relatively long interval and it is not mentioned in the article to which extent the focusing had to be adjusted at these controls or not. But it can be assumed that the hit-rate with the continuous US-tracking system was superior to that achieved when only fluoroscopy was used. Unfortunately, the fluoroscopy times were not reported. I have no experience with the two lithotripters used in this comparison: LM-9200 ELMA and EM-1000, but the authors describe them as low-frequency lithotripters. [img]https://www.storzmedical.com/images/blog/ChangTH.JPG[/img] The results in this report are highly interesting and it is desirable to use US more commonly with SWL to reduce the x-ray dose. It is, however, difficult to correctly interpret the ultrasound image compared with the fluoroscopic image and it is possible that AI can be a useful assistant for the further development of this step. When the learning threshold is passed, there are some other requirements that are necessary for making US-tracking attractive and effective. The equipment must be maximally user friendly, allow for automatic tracking and enable remote control. Reference. Chang CC et al. In vitro study of the revised ultrasound based real time tracking of renal stones for shock wave lithotripsy. Part 1. J Urol 2013;189:2357-2363. DOI:10.1016/j.juro.2012.11.111 Hans-Göran Tiselius

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