Shock Wave Lithotripsy is More Effective for Residual Fragments after Percutaneous Nephrolithotomy than for Primary Stones of the Same Size: A Matched Pair Cohort Study

The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study

PURPOSE

Residual fragments not removed with urinary stone surgery may become symptomatic. In this context, this study was carried out to investigate the effect of performing retrograde intrarenal surgery, which is conventionally performed in the lithotomy position, in the modified lithotomy position (Trend-side) on stone-free rates following the surgery.

METHODS

This prospective study consisted of 100 patients with a single kidney stone smaller than 2 cm between 2021 and 2023. These patients were randomized into two groups of 50 patients each to be operated on in the conventional lithotomy and Trend-side positions. Variables were compared using independent t test for continuous variables and chi-square test for categorical variables.

RESULTS

There was no significant difference between the lithotomy and Trend-side position groups in terms of preoperative size, density, location of the stone, and hydronephrosis degree. Stone-free rate was 72% (n = 36) in the lithotomy group and 92% (n = 46) in the Trend-side group. Hence, there was a significant difference between the groups in the stone-free rate in favor of the Trend-side group (p = 0.009). Fragmentation time was statistically significantly shorter in the Trend-side group than in the lithotomy group (34 ± 17 min vs. 43 ± 14 min; p = 0.006). There was no significant difference between the groups in postoperative complication rates.

CONCLUSION

Performing retrograde intrarenal surgery in the Trend-side position shortened the duration of fragmentation compared to the lithotomy position and was associated with higher stone-free rates. In conclusion, the Trend-side position can be safely preferred in patients undergoing retrograde intrarenal surgery due to kidney stones.

Residual Stone Fragments After Percutaneous Nephrolithotomy: Shockwave Lithotripsy vs Retrograde Intrarenal Surgery

Background: Despite technology incorporation to percutaneous nephrolithotomy (PCNL), residual stone fragments (RSFs) may still persist after PCNL and need to be addressed to avoid regrowth or ureteral obstruction. The objective of this study was to compare the outcomes of retrograde intrarenal surgery (RIRS) to extracorporeal shockwave lithotripsy (SWL) for treating patients with RSFs after a previous standard PCNL. Materials and Methods: Adult patients with RSF after a standard PCNL submitted to RIRS or SWL in our Institution from January 2017 to January 2020 were retrospectively studied. Stone-free rate (SFR) was evaluated on postoperative day (POD) 90 by noncontrast CT (NCCT) or ultrasound and kidney, ureter, and bladder radiograph (KUB) for each renal unit. Surgical complications based on Clavien-Dindo classification during the 90 days of follow-up were recorded. Sample size was calculated for a power of 80% and a significance level of 0.05, assuming SFR of 20% for SWL and 50% for RIRS. Results: Thirty-three patients treated by SWL were compared with 36 patients treated by RIRS. Hospitalization time was longer in the RIRS group (4.18 vs 12.33 hours, p = 0.001). SFR and success rate were lower in SWL than RIRS group (24.2% vs 58.3%, p = 0.007 and 30.3% vs 72.2%, p = 0.004, respectively), using POD 90 NCCT in 81.8% and ultrasound and KUB in 18.2% of the SWL group and using POD 90 NCCT in 100% of the RIRS group. Minor complications (Clavien-Dindo < III) occurred in 11 of 36 (30.6%) patients submitted to RIRS and in 2 of 33 (6.1%) patients submitted to SWL group (p = 0.025). Two patients (6.1%) of the SWL group had Clavien-Dindo IIIb complication owing to Steinstrasse and were submitted to ureteroscopy. Emergency room visits were similar between groups (6.1% vs 8.3%, p = 1.0). Conclusions: RIRS has better SFR, higher minor complications, and lower major complications than SWL for the treatment of RSFs after standard PCNL.

Impact of Stone Size, Location, and Stone Composition on the Efficacy of Extracorporeal Shock Wave Lithotripsy for Residual Stone after Percutaneous Nephrolithotomy

This study aimed to determine the impact of stone size, location and stone composition the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the management of residual stone after percutaneous nephrolithotomy (PCNL). The design of this study was a retrospective that conducted between January 2012 until December 2016. The population in this study were all patients with residual stones post PCNL. Exclusion criteria were patients with multiple stones and patients with a history of previous treatment for residual stones such as nephroscopy, flexible ureterorenoscopy, ESWL or medical therapy). The variables studied in this study were stone size, stone location, and stone composition. Before ESWL was carried out, all patients underwent Kidney Ureter Bladder (KUB). After ESWL, all patients underwent ultrasonography (USG) and KUB to determine the stone clearance status. The sample of this study was 125 patients. The overall stone-free rate (SFR) of ESWL in managing post-PCNL residual stones is 72%. SFR based on stone size variable are 73.7% and 71.3% respectively for stones with a size = 5 mm and >5 mm (p = 0.78). SFR based on stone location variable was 67.1%, 75.8%, and 81.8% respectively for the residual stone located at the upper pole, middle pole and lower pole. There are no significant differences in the entire variable. This study concludes that ESWL can be used as effective additional management to treat post-PCNL residual stones with satisfactory SFR.