ESWL and Triple Fire Lithotripter

Abstract

The ideal lithotripter which all companies hope to achieve in the near future, should be characterized by high efficacy, low impact on the patient's sensitivity to pain and least detrimental action on the surrounding tissues. Yet, even the most modern technology seems to be still very far from achieving these goals. For around 1 year our Department has been using the last generation lithotripter Piezolith 3000^® (variable triple-focus). Compared to its predecessor, this machine has some changes such as: a) triple focus module that allows to adjust the focal distance to the size of the calculation, b) greater focal depth ranging from 15 cm in Piezolith 3000^® fixed focus to 16.5 cm in the new lithotripter, allowing for an easier and more effective treatment of obese patients, c) increase in power by opening the SW variable focal length (F1: 0.20–3.26 mJ/mm₂, F2: 0.08–1.64 mJ/mm₂, F3: 0.030–0.41 mJ/mm₂). The objective of our work is to assess whether the technical characteristics of the new Piezolith 3000^® determine a real improvement in management of urinary calculi.

Methods

265 patients undergoing ESWL with variable triple-focus lithotripter from January 2008 to January 2009 (Group A) were compared to 265 patients treated with an equal lithotripter Piezolith 3000^® fixed focus (Group B). The two groups were homogeneous as for the following variables: age, size and location of the calculi, which are distributed as follows: superior calyx (6), medium (20), inferior (32), renal pelvis (36), pyeloureteral junction (12), lumbar ureter (50), iliac (12), pelvis (6), iuxtavesical (70), bladder (7), multiple sites (14). The ESWL was performed in both groups with ultrasound exclusive point.

Results

In Group A the time of fragmentation is lower compared to Group B (p<0.01), with fewer days required for fragment expulsion and lower number of re-treatments (p<0.05). The latter result is probably due to increased average energy applied (2.35 mJ/mm₂). However, the increase of this energy results in parallel increased perception of pain during ESWL.

Conclusions

Piezolith 3000^® represents a real improvement in the effectiveness of fragmentation but there is, compared to the previous model, a significant reduction in the time of expulsion. This suggests that this variable is affected by other factors.