Ultrasonic Lithotripsy Techniques

Comparison of Ultrasonic and Pneumatic Intracorporeal Lithotripsy Techniques during Percutaneous Nephrolithotomy

2017-12-12

Comparison of Ultrasonic and Pneumatic Intracorporeal Lithotripsy Techniques during Percutaneous Nephrolithotomy

Abstract

Objectives. To compare the effectiveness and safety of ultrasonic and pneumatic lithotripters in the treatment of renal stone disease. Materials and Methods. A total of 227 consecutive percutaneous nephrolithotomy procedures for renal calculi were performed. In 107 patients ultrasonic lithotriptors were used (group I) and in 83 patients pneumatic lithotriptors were used (group II). In the remaining 37 patients, stones were managed with both pneumatic and ultrasonic lithotripters. Follow-up studies included intravenous urography (IVU) and/or computed tomography (CT). Results. The mean operative time and duration of hospitalization were similar between the groups. In the ultrasonic treatment group, 100 (96.9%) patients were stone-free on postoperative day 1 and 5 (4.6%) went on to undergo an additional treatment modality, resulting in a total stone-free rate of 97.2%. In the pneumatic lithotripsy group, 68 (81.9%) patients were stone-free after the primary procedure on the first day and 15 (18.1%) went on to undergo an additional treatment modality, resulting in a stone-free rate of 91.5%. The final stone-free rates at 3 months postoperatively in groups I, II, and III were 97.2%, 91.5%, and 87.9%, respectively (p=0.826). Conclusions. We conclude that both ultrasonic and pneumatic lithotripters are effective and safe for intracorporeal lithotripsy. However, the ultrasonic lithotripter provides higher stone-free rates with similar morbidity compared with pneumatic devices.

Introduction

Percutaneous nephrolithotomy (PNL) has become the preferred method for treatment of large renal calculi since this modality was first utilized in 1976 by Fernström and Johanson [1]. This technique has the advantages of higher stone-free rates, cost effectiveness, and early convalescence compared with other modalities such as shock wave lithotripsy (SWL) and open surgery [2, 3]. Intracorporeal lithotripsy is one of the most important steps that affect the success rate of this surgical method, and for this step pneumatic and ultrasonic lithotripters are commonly used energy sources [3]. In this study, we aimed to compare the success rates of pneumatic and ultrasonic lithotripsy techniques during PNL.

Discussion

Renal stone treatment options have changed dramatically during the last two decades with the technological advancement of instruments . Today PNL is the first choice treatment modality for most renal stones larger than 2 cm, multiple renal stones, and also for complex renal calculi [. The introduction and advances in various forms of intracorporeal lithotripters, especially ultrasonic and pneumatic devices, have improved the stone-free rates after PNL, while concomitantly decreasing the risk of complications.

These various intracorporeal lithotripters work on different physical principles of stone fragmentation . Pneumatic lithotripters work on the same principle as collision with a bullet; on impact, energy transmits compressed air pulses within a steel probe to the calculi to be fragmented [. This technique offers safe, cheap, and effective clearance of calculi, and it is particularly useful for large and hard stones. Also, all stones can be destroyed regardless of their composition, but subsequent extraction of the stone fragments is required . According to the literature, the success rate of pneumatic lithotripsy appears to be higher than 84% . In this study, we achieved an overall success rate of 90.8%, which is similar to that in the literature regarding the general results of PNL. Our results show the effectiveness and safety of this technique.

Ultrasonic lithotripsy is still the most commonly used lithotripter with rigid nephroscopes during PNL . It fragments stones into small pieces and has the ability to aspirate these particles through the hollow bore of the transducer, which eliminates manual stone extraction This technique was the standard method of lithotripsy for many years, with a fragmentation rate of 97% . Although this lithotripsy technique has high success rates, it is not universally successful, especially in the setting of hard stones, such as calcium oxalate monohydrate and cysteine [. Another disadvantage is the potential for overheating due to conversion of vibration energy to heat energy . Nevertheless, overheating of the probe can cause tissue injury. In a rat model, Diri et al. noted that ultrasonic devices have a potential risk for tissue injury [. They showed a significant increase in inflammation, papillary projection, stratification, and microscopic or macroscopic stone formation in the bladder wall of rats which was treated with ultrasonic lithotripsy.

In the present study, we compared the efficacy and safety of the standard ultrasonic device with those of a pneumatic lithotripter and the combined use of pneumatic and ultrasonic devices. There were no significant differences in the complication rates, mean operative times, and mean hospitalization times between the three groups. However, there was a higher percentage of stone-free patients in the ultrasonic lithotripsy group than pneumatic and combined lithotripsy groups.

This series has some limitations, including its retrospective nature and relatively small number of patients. However, the most important limitation of the present study is that there was a significant difference in stone size between the 3 groups. Therefore, our findings must be confirmed by further prospective randomized studies

Conclusion

In the present study, pneumatic and ultrasonic lithotripters were compared, and both of them were found to be effective, safe, and reliable management modalities. However, the ultrasonic lithotripter provided higher stone-free rates with similar morbidity compared with pneumatic devices.

Reference

[1]B. Resorlu, A. Unsal, A. Tepeler et al., “Comparison of retrograde intrarenal surgery and mini-percutaneous nephrolithotomy in children with moderate-size kidney stones: results of multi-institutional analysis,” Urology, vol. 80, pp. 519–523, 2012

[2]T. Akman, M. Binbay, F. Ozgor et al., “Comparison of percutaneous nephrolithotomy and retrograde flexible nephrolithotripsy for the management of 2–4 cm stones: a matched-pair analysis,” BJU International, vol. 109, no. 9, pp. 1384–1389, 2012

[3]C. L. Teh, P. Zhong, and G. M. Preminger, “Laboratory and clinical assessment of pneumatically driven intracorporeal lithotripsy,” Journal of Endourology, vol. 12, no. 2, pp. 163–169, 1998

[4]M. Atar, M. N. Bodakci, A. A. Sancaktutar et al., “Comparison of pneumatic and laser lithotripsy in the treatment of pediatric ureteral stones,” Journal of Pediatric Urology, vol. 9, pp. 308–312, 2013

Hangzhou Altrasonic Technology Co., Ltd located in Hangzhou, China, was found in the 1990s, and is a subsidiary of Sunrise Group, a largest trading and manufacturing company in Hangzhou, China. Altrasonic has many years'experiences in the business of industrial ultrasonic components and ultrasonic devices in China. We use this experience and experise to provide only the best ultrasonic devices and components based on the competitive price.
Altrasonic equipment focused on the r&d of high power ultrasound applications, Altrasonic has absolute leading core technology, the most stable and mature manufacturing technology, rich experience, can provide direct ultrasonic application scheme demonstrate, structure design, system configuration and related parts production.

Altrasonic equipment cooperated with the key graphene manufacturers, applied the ultrasound equipment in graphene preparation process of industrialization firstly, and make the ultrasonic be a good supporting to the large-scale preparation of the high quality and low cost graphene materials.