Appropriate cutoff for treatment of distal ureteral stones by single session in situ extracorporeal shock wave lithotripsy

Effectiveness of ultrasound-guided shockwave lithotripsy and predictors of its success rate in pediatric population: A report from a national reference center

OBJECTIVE

Shockwave lithotripsy (SWL) remains a well-established treatment modality for many of the pediatric renal and ureteral stones. Repeated SWL sessions carry limitations due to the use of general anesthesia and X-ray radiation. The objective of our study was to evaluate stone-free rate (SFR) of 1-session of SWL for the management of pediatric renal and ureteral stones less than 2 cm performed exclusively under ultrasound guidance and identify factors influencing its success.

METHODS

The study utilized a retrospective cohort design including 124 consecutive pediatric patients with 133 renal and ureteral stones less than 2 cm whom SWL was performed in the period of January 2008 to December 2019. SWL procedures were performed by one expert surgeon in a single, national reference center, exclusively under ultrasound guidance using Modulith® SLK lithotripter. Follow-up was performed in post-SWL 2nd, 4th, 12th weeks and 6 months.

RESULTS

The mean age of the children was 10 years (SD = 6.0) and the mean stone size was 10.4 mm (SD = 3.6 mm). Sedation type of anesthesia was used in 80 patients (64.5%). No major complication was developed, and no ureteral stenting was required in any of the patient following SWL. The SFR following 1-session of SWL was 88.0% at 12-week. Younger age (P = 0.002), sedation type of anesthesia (P = 0.001) and presence of radiolucent stones (P = 0.033) significantly improved post-SWL early stone clearance on univariate analysis, the latter being the only significant factor according to final model (P = 0.031).

CONCLUSIONS

Ultrasound-guided SWL represents a safe and effective method for the management of both renal and ureteral stones in children. The SFR following 1-session of SWL at 12-weeks was achieved in 88.0%, the overall success rate after all SWL sessions reaching 91.7%. A higher success rate was observed in children harboring radiolucent stones.

Comparative study of extracorporeal shock wave lithotripsy outcomes for proximal and distal ureteric stones

OBJECTIVE

To assess the efficacy of extracorporeal shock wave lithotripsy (ESWL) monotherapy for isolated proximal ureteral calculi and compare it to that for isolated distal calculi.

PATIENT AND METHODS

We treated 68 patients with isolated ureteral stones using MPL 9000. Stones were located in the proximal and distal ureters in 44 and 24 patients, respectively. Patients were stratified according to stone burden and degree of obstruction. Data of all patients were prospectively collected for stone burden, stone localization, number of sessions, number of shock waves, stone-free rates (SFRs), complications, re-treatment rates and auxiliary procedures. Outcomes regarding ureteral localization were compared.

RESULTS

The overall SFR was 85.3% with a 41.2% re-treatment and 17.6% auxiliary procedure rate. The mean number of shock waves applied for each stone was not different among the two ureteral locations. The SFRs were 86.3% and 79.1% for proximal and distal ureteral stones, respectively (P=0.17). For the group with stones <100 mm(2), the SFR was 85.4% and 89.5% for the proximal and distal ureter, respectively. Although the degree of obstruction did not affect SFR of the entire group (P=0.12) and the proximal ureter group (P=0.96), it adversely affected SFR in the distal ureter (P=0.017).

CONCLUSIONS

ESWL outcomes for the ureteral calculi support the use of lithotripsy particularly for stones <100 mm(2). Treatment efficacy was not significantly different among stones localized in proximal and distal ureters. Degree of obstruction did not affect the ESWL outcomes in the proximal ureter, but it adversely affected SFR in the distal ureter.

Efficacy and safety of endoscopic treatment of ureteral stones in pediatric age

Ureteroscopy procedures in pediatric age are becoming more and more common thanks to the availability of smaller caliber instruments, and of improved endoscopic techniques. The efficacy of this procedure in pediatric age is still discussed nowadays. This paper aims at reviewing all cases of ureteral lithiasis treated by ureteroscopy plus intracorporeal lithotripsy (ULT), as well as verifying efficacy and safety of this procedure in pediatric age.

Materials and Methods

From July 2002 to May 2006, 37 patients (26 female, 11 male; mean age 7.4 years; range 2–17) were treated by ULT for ureteral stones: 30 in distal, 4 in middle and 3 in proximal ureter. Median size of stones was 7mm (range 3–13mm). Dilation of the ureteral meatus was necessary in 2 patients only. Endoscopic procedure was similar to adult patients. Outcomes were statistically compared with current literature data.

Results

In 36 (97.3%) out of 37 patients ULT proved successful. All patients having stones in distal (30) and middle (4) ureter were stone-free at the end of treatment. Stone migration into the kidney pelvis occurred in 1 patient with proximal ureter stones (66.7% stone-free rate): an ESWL treatment was therefore performed. 1 case only (2.7%) developed a perioperative complication (stone migration). Hematuria and flank pain in 4 patients (10.8%) were the most common reported post-operative complications. A stone-free state was confirmed at 1 and 3 months for all 36 patients. There was no evidence of ureteral strictures and/or ureteral refluxes.

Conclusions

Smaller caliber ureteroscopes confirmed ULT as the first-choice treatment procedure in children affected by ureteral lithiasis, thanks to its efficacy and safety.