Extracorporeal shock wave lithotripsy: retrospective study on possible predictors of treatment success and revisiting the role of non-contrast-enhanced computer tomography in kidney and ureteral stone disease

Extracorporeal shock wave lithotripsy (ESWL) is a safe and efficient treatment option for urinary stone disease. The overall stone-free rate (SFR) varies significantly. This study aimed to assess the influence of stone size, location, stone density, and skin-to-stone distance (SSD), on the outcome of ESWL. We assessed whether pre-treatment non-contrast-enhanced CT scan (NCCT) confers significant advantages compared to kidney-ureter-bladder film (KUB) only. We reviewed the medical records of 307 cases (165 men, 142 women) with renal and ureteral stones treated consecutively at our institution with ESWL between 2020 and 2023. 44 of these underwent a NCCT. The outcome of ESWL was defined in two ways: visible stone fragmentation on KUB, and the need for further treatment. Overall success of fragmentation was 85% (261 patients). 61% of patients (n = 184) didn't need any further treatment. Stone size and location correlated significantly with treatment outcomes regarding the need for further treatment (p = 0.004) and stone fragmentation (p = 0.016), respectively. Unlike mean SSD (p = 0.462), the mean attenuation value (MAV) significantly correlated with the need for retreatment (p = 0.016). MAV seems to be a better predictor of treatment success (AUC of the ROC curve: 0.729), compared to stone size (AUC: 0.613). The difference between groups (with and without NCCT) in both treatment outcomes did not reach statistical significance. During decision-making, information regarding SSD and MAV can be useful in more dubious scenarios. However, it appears that their inclusion doesn't provide substantial advantages when compared to relying solely on KUB.

Safety and efficacy of Chinese minimally invasive percutaneous nephrolithotomy in the management of renal stones ≤ 2 cm: a single-center experience

Background

The goal for using smaller caliber instruments in PNL was to reduce the access-related complications and to decrease morbidity. The objective of this study was to evaluate the safety and efficacy of Chinese minimally invasive percutaneous nephrolithotomy (MIPNL) in the treatment of renal stones ≤ 20 mm.

Results

Sixty-seven patients completed the study protocol. The mean age was 41.10 ± 13.99 years (range 18–68 years). There were 43 (64%) male and 24 (36%) females. The mean stone size was ranged from 78.5 to 439.6 mm2 (mean ± SD 172.48 ± 69.54 mm2). The overall SFR was (82%). Twelve (18%) needed post-MIPNL auxiliary procedure, in the form of second MIPNL in 3 (4.5%) cases, SWL in 7 (10%), and RIRS in 2 (3%) cases. The intraoperative complication was present in four patients (5%) include bleeding necessitate blood transfusion in one patient (1.5%) and renal collecting system perforation 3 (4.5%). The postoperative complication was urine leakage 5 (7.5) and fever in 6 (9%) of patients.

Conclusion

Chinese MIPNL is safe and effective method for treatment of renal stone ≤ 20 mm size with satisfactory SFR and low complication rate when SWL failed or contraindicated. It is considered a feasible treatment alternative to standard PNL, in the absence of flexible URS or miniature nephroscope.

The "old" 15 mm renal stone size limit for RIRS remains a clinically significant threshold size

PURPOSE

To investigate the performance of retrograde intrarenal surgery (RIRS) for the 1-2 cm renal stone size range in comparison to smaller stones.

MATERIALS AND METHODS

From a data base of 3000 ureteroscopies between 2004 and 2014, 635 consecutive patients underwent RIRS for renal stones. Patients were divided to three groups according to their renal stone size (<10, 10-15, 15-20 mm). Preoperative, operative, stone free rate (SFR) and follow-up data were analyzed and compared.

RESULTS

The SFR for the three groups was 94.1, 90.1 and 85%, respectively. Patients with renal stone size above 15 mm had a statistically significantly lower SFR. The efficiency quotient calculated for stones larger and smaller than 15 mm was 83.9 vs. 91.8%, respectively (p < 0.01). The mean operative time and hospital stay were longer for patients with renal stones larger than 15 mm (73.6 ± 29.9 vs. 53 ± 19.4 min, p < 0.01 and 2.2 ± 2 vs. 1.8 ± 1.8 days, p = 0.031, respectively). Moreover, the complication rate was almost two times higher (10 vs 5.4%, p = 0.08). Concomitant ureteral stones and older age were independent predictors of failure in the large stone group.

CONCLUSIONS

While the overall SFR following RIRS for renal stones up to 2 cm is generally high, the SFR for 15-20 mm stones is significantly lower, with a longer operating time and hospital stay, and a higher complication rate.

Review on Lithotripsy and Cavitation in Urinary Stone Therapy

Cavitation is the sudden formation of vapor bubbles or voids in liquid media and occurs after rapid changes in pressure as a consequence of mechanical forces. It is mostly an undesirable phenomenon. Although the elimination of cavitation is a major topic in the study of fluid dynamics, its destructive nature could be exploited for therapeutic applications. Ultrasonic and hydrodynamic sources are two main origins for generating cavitation. The purpose of this review is to give the reader a general idea about the formation of cavitation phenomenon and existing biomedical applications of ultrasonic and hydrodynamic cavitation. Because of the high number of the studies on ultrasound cavitation in the literature, the main focus of this review is placed on the lithotripsy techniques, which have been widely used for the treatment of urinary stones. Accordingly, cavitation phenomenon and its basic concepts are presented in Section II. The significance of the ultrasound cavitation in the urinary stone treatment is discussed in Section III in detail and hydrodynamic cavitation as an important alternative for the ultrasound cavitation is included in Section IV. Finally, side effects of using both ultrasound and hydrodynamic cavitation in biomedical applications are presented in Section V.

Role of Tamsulosin Therapy after Extracorporeal Shockwave Lithotripsy for Renal Stones: Randomized Controlled Trial

INTRODUCTION

To evaluate the efficacy of adjunctive tamsulosin therapy after extracorporeal shockwave lithotripsy (SWL) for renal stones.

MATERIALS AND METHODS

This prospective study was conducted on patients who underwent single-session SWL for solitary renal stone less than 20 mm. Post-SWL, patients were randomly divided into 2 groups; the tamsulosin group (TG), received a daily dose of tamsulosin 0.4 mg, for a maximum of 12 weeks, with post-SWL traditional analgesia and control group (CG), received the traditional analgesia alone.

RESULTS

The study enrolled 271 patients and eventually only 249 (123 in TG and 126 in CG) completed the study. The overall stone free rate was 73.5%: 78.0% in TG and 69.0% in CG (p = 0.108). In TG, 8.1% of patients experienced at least one episode of acute renal/ureteral colic compared with 19.8% of controls (p = 0.008). The mean cumulative analgesia dosage per subject was 313 mg in TG and 346 mg in CG (p < 0.001). Overall, 14 patients developed steinstrasse and 6 of them (all in CG) needed urgent intervention (p = 0.031).

CONCLUSIONS

Daily tamsulosin therapy does not enhance the clearance of stone fragments but decreases the pain episodes, analgesia dosage and need for adjuvant intervention after SWL for renal stones.