Treatment of renal lower pole stones: an update

Comparative Analysis of Super-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for the Management of Renal Calculi ≤2 cm Among Somali Population

Background: Limited data have explored the efficacy of super-mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) in managing ≤2 cm renal calculi. This study aims to comprehensively evaluate the safety and effectiveness of SMP compared with RIRS. Methods: This prospective cohort study investigated 210 patients with renal calculi (≤2 cm) undergoing SMP or RIRS, randomly recruited over 4 years. In total, 51.4% underwent SMP and 48.6% underwent RIRS. Results: The mean patient age was 31.3 ± 14.7 years; 56.7% were men, mean stone size of 1.3 ± 0.28 cm, and stone hardness of 1190.1 ± 352.83 Hounsfield units. Pearson's correlation indicated negative correlations for SMP with hospital stays (r = -0.138, p = 0.046), operating time (r = -0.519, p < 0.001), and stone-free rate (SFR) (r = -0.161, p = 0.020); and a positive correlation with a postoperative ureteral catheter (r = +0.389, p < 0.001). With regard to RIRS, the study shows a positive correlation with hospital stay (r = +0.138, p = 0.046), operating time (r = +0.519, p < 0.001), and SFR (r = +0.161, p = 0.020); and a negative correlation with postoperative ureteral catheter (r = -0.389, p < 0.001). Logistic regression, using SMP as the reference, RIRS was associated with β = +0.31, and 1.20 (95% confidence interval [CI], 1.14-1.27, p ≤ 0.001) risk of operation duration and β = +0.37, 1.44 (95% CI, 1.00-2.07, p = 0.047) risk of longer hospital stay. Conclusion: This study investigates the suitability of SMP and RIRS for treating renal calculi ≤2 cm. SMP demonstrated superior efficacy with significantly shorter operating times and reduced hospital stays, suggesting potential advantages for managing lower volume renal stones.

Relocation of lower pole renal stones helps improve the stone-free rate during flexible ureteroscopy with a low complication rate

OBJECTIVE

To compare the efficacy and safety of relocating the lower pole stones to a favorable pole during flexible ureteroscopy with in situ lithotripsy for the treatment of 10-20 mm lower pole stone (LPS).

METHODS

This study was a prospective analysis of patient outcomes who underwent an FURS procedure for the treatment of 10-20 mm lower pole renal stones from January 2020 to November 2022. The patients were randomized into a relocation group or in situ group. The LPSs were relocated into a calyx, during lithotripsy in the relocation group was performed, whereas the in situ group underwent FURS without relocation. All the procedures were performed by the same surgeon. The patients' demographic data, stone characteristics, perioperative parameters and outcomes, stone-free rate (SFR), complications, and overall costs were assessed retrospectively.

RESULTS

A total of 90 patients were enrolled and analyzed in this study (45 per group) with no significant differences between the two groups in terms of age, gender, BMI, diabetes, hypertension, stone size, number, laterality, composition, and density. The mean operation time, total energy consumption, postoperative stay, and complications were similar between the groups. Both groups had similar SFR at 1 day postoperative follow-up (p = 0.091), while the relocation group achieved significantly higher SFR 3 months later (97.8% vs 84.4%, p = 0.026). The relocation group also had a significantly higher WisQol score than the in situ group (126.98 vs 110.18, p < 0.001).

CONCLUSION

A satisfactory SFR with a relatively low complication rate was achieved by the relocation technique during the FURS procedure.

Retrospective study of single-use digital flexible ureteroscopic lithotripsy versus miniaturized percutaneous nephrolithotomy for 1.5-2.5cm lower pole renal stones

PURPOSE

Retrospective analysis was performed on the clinical information of patients with 1.5-2.5 cm lower pole renal stones treated by single-use digital flexible ureteroscopic lithotripsy (fURS) and miniaturized percutaneous nephrolithotomy (MPCNL) in affiliated hospital of the Nantong University from January 2020 to December 2022. To compare the safety and efficacy of single-use fURS and MPCNL in the treatment from 1.5cm to 2.5cm lower pole renal stones.

METHODS

Clinical information of 141 patients were collected and divided into single-use fURS group and MPCNL group according to their treatment methods, including 83 patients in the single-use fURS group and 58 patients in the MPCNL group. Baseline data, data on the clinical characteristics of stones, laboratory examination data, operation time, and postoperative data of the two groups were collected. Statistical analysis was made on the collected data to analyze the differences and causes between the two groups of patients.

RESULTS

There was no significant difference in the baseline data and preoperative clinical features of 141 patients between the two groups (P > 0.05). In comparison of postoperative serum indexes, the drop values of hemoglobin and creatinine in single-use fURS group were lower than those in MPCNL group, and the difference was statistically significant (P < 0.05). The stone free rate was higher in the MPCNL group than in the single-use fURS group on the first day after surgery. At the 1st month after surgery, the two groups were similar. At 3rd month after surgery, the single-use fURS group was slightly higher than the MPCNL group, with no statistical significance (P > 0.05). The total complication rate in single-use fURS group was slightly lower than that in MPCNL group, but there was no statistical significance (P > 0.05).

CONCLUSIONS

Single-use fURS has similar safety and efficacy to MPCNL in the treatment of 1.5-2.5cm lower pole renal stones. Single-use fURS may be a new option for the treatment of these stones.

Cystine Stones: Developments in Minimally Invasive Surgery and Their Impact on Morbidity and Stone Clearance

Cystinuria is a rare genetic condition that is responsible for cystine stones. Besides stone recurrence, patients with cystine stones have reduced health-related quality of life, increased rates of chronic kidney disease and hypertension. Although lifestyle measures, medical therapy and close follow up are essential to reduce and monitor cystine stone recurrences, surgical intervention is frequently needed for most cystinuria patients. Shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and active surveillance all have a role, and technological advances in endourology are vital in achieving a stone-free status and to prevent recurrences. The complexity of managing cystine stones necessitates a multidisciplinary team discussion, patient involvement and an individualised approach in a specialist centre for optimum management. Thulium fibre laser and virtual reality may have an increasing role in the future of cystine stone management.

Efficacy and safety of surgical treatment for 1-2 cm sized lower pole of renal stone: network meta-analysis of randomized control trials

The management of medium-sized (1-2 cm) lower poles renal stone has been a contentious topic for endourologists. There are limited evidences to answer the best management options for medium-sized lower pole renal stone. This network meta-analysis provided high-level evidences on efficacy and safety of profile of PCNL, Mini-PCNL, Ultra-PCNL, RIRS, Micro-PCNL, SWL for management of medium-sized lower pole renal stone. Systemic review and network meta-analysis (NMA) of randomized control trials was conducted. The PICOS (Population, Interventions, Comparison, Outcomes, and Study) approach was used to look for relevant studies. Searches were conducted at major electronic databases like Medline via PubMed, Embase, Google Scholar, SCOPUS, ScienceDirect, Cochrane library, Web of Science, and ClinicalTrials.gov to find relevant articles from the inception to April 19, 2023. Fourteen randomized control trials involving 2194 patients were among these studies that met the eligibility criteria. Pooled SFR was Mini-PNCL 98% (95% CI 96-99%), Ultara-PCNL 96% (95% CI 93-98%), RIRS 90% (95% CI 88-92%), PCNL 88% (95% CI 85-92%), Micro-PCNL 77% (61-88%) and SWL 69% (95% CI 65-74%). Mini-PCNL provided a statistically significant higher SFR compared to RIRS (RR = 2.43 91.52; 3.89)), Micro-PCNL (RR = 3.19 (1.09; 9.38)), and SWL (RR = 6.17 (3.65; 10.44)), but there was no statistical significance with standard PCNL (RR = 1.06 (0.52; 2.16)) and Ultra-PCNL (RR = 1.37 (0.75; 2.51)) for management of medium-sized lower pole renal stone. The order of SUCRA values for complication rate was as follows: PCNL(90%), Micro-PCNL(70%), Mini-PCNL(50%), Ultra-PCNL(50%), RIRS(40%), and SWL(10%). The current pooled evidence from fourteen randomized control trials revealed that Mini-PCNL, Ultra-PCNL, and standard PCNL are likely the best treatments for medium-sized lower poles when SFR over a short period of minimal session is a priority. These treatment options have a higher rate of complications, longer hospital stays, and acceptable operations time. RIRS and SWL treatment have acceptable efficacy stone-free rate with low complication rate, short hospital stays, and operation time. These treatment option would be the best fit for solitary kidney, coagulopathy, and comorbidity.

The feasibility of ultrasound-guided mini-percutaneous nephrolithotomy for ESWL-resistant lower calyx renal stones of up to two centimeters: a single center experience

Lower pole renal stones present a significant challenge in urologic practice due to difficulty in accessing the calyx and eliminating fragments. Management options for these stones include watchful waiting for asymptomatic stones, extracorporeal shock wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL). Mini-PCNL is a newer modification of conventional PCNL. The study aimed to assess the feasibility of mini-PCNL in treating lower pole renal stones equal to or less than 20mm that were not responsive to ESWL therapy. We included 42 patients (24 male and 18 female) with a mean age of 40±2.3 who underwent mini-PCNL at a single urology center between June 2020 and July 2022 and assessed operative and postoperative outcomes. The mean total operative time was 47±3.11 minutes, ranging from 40 to 60 minutes. The stone-free rate was 90%, and the overall complication rate was 26%, which included minor bleeding (5%), hematuria (7%), pain (12%), and fever (2%). The mean hospital stay was 80±3.34 hours (3-4 days). Our findings suggest that mini-PCNL is an effective treatment option for lower pole renal stones that are not responsive to ESWL therapy. The immediate stone-free rate was high, with minimum non-serious complications.

The efficacy of retrograde intra-renal surgery (RIRS) for lower pole stones: results from 2946 patients

PURPOSE

To evaluate the perioperative outcomes of retrograde intra-renal surgery (RIRS) for lower pole stones (LPS) and factors affecting stone-free rate (SFR).

METHODS

Data from 20 centers were retrospectively reviewed. Inclusion criteria were adult patients, normal renal anatomy, and LPS. Exclusion criteria were bilateral surgery, concomitant surgery for ureteral stones. SFR was defined as a single residual fragment (RF) ≤ 2 mm and evaluated 3-months after surgery. A multivariable logistic regression analysis was performed to assess factors associated with RF. Statistical significance was set at p value < 0.05.

RESULTS

2946 patients were included. Mean age and stone size were 49.9 years 10.19 mm, with multiple LPS in 61.1% of cases. Total operation and laser time were 63.89 ± 37.65 and 17.34 ± 18.39 min, respectively. Mean hospital stay was 3.55 days. Hematuria requiring blood transfusion and fever/urinary infections requiring prolonged antibiotics occurred in 6.1% and 169 5.7% of cases, while sepsis with intensive-care admission in 1.1% of patients. On multivariate analysis, Multiple stones (OR 1.380), stone size (OR 1.865), and reusable ureteroscopes (OR 1.414) were significantly associated with RF, while Thulium fiber laser (TFL) (OR 0.341) and pre-stenting (OR 0.750) were less likely associated with RF.

CONCLUSIONS

RIRS showed safety and efficacy for LPS with a mean diameter of 10 mm. This procedure can achieve a satisfactory SFR in pre-stented patients with a single and smaller stone, particularly with TFL use.

Outcomes in Lower Pole Kidney Stone Management Using Mini-Percutaneous Nephrolithotomy Compared With Retrograde Intra Renal Surgery: A Randomized Controlled Trial

Background Because of the anatomical properties of the inferior calyx, lower pole stones are difficult to remove through the ureter, even if the stones are fragmented. Retrograde intra-renal surgery (RIRS) is typically employed to treat the smaller lower pole stones (1.0-2.0 cm) while percutaneous nephrolithotomy (PCNL) is primarily used to treat the larger diameter stones or when RIRS has failed to clear the stones. This study was conducted to compare mini-PCNL and RIRS for the management of lower pole kidney stones in terms of stone clearance. Material and methods This randomized control trial was conducted in the Department of Urology, Shaikh Zayed Hospital, Lahore from October 2020 to December 2022. A total of 150 patients between the ages of 18 and 80 years with a kidney stone size of 10-20 mm at the lower pole were included. Patients with positive urine culture, anatomical abnormalities, uncontrolled diabetes (hemoglobin{Hb}A1c >9%), and undergone previous renal surgery were excluded. Group A patients were treated with mini-PCNL, while group B patients were managed with RIRS. Follow-up visits were planned four weeks postoperatively with CT KUB (computed tomography of kidneys, ureters, and bladder) plain to assess stone clearance. Results The mean age in group A was 43.27 ± 13.86 years, while in group B was 45.32 ± 14.14 years. Out of 150 patients, 102 (68.0%) were males and 48 (32.0%) were females. Mean size of the stone was 15.30 ± 2.21 mm. Stone clearance after mini-PCNL was found in 69 (92.0%) patients and after RIRS in 59 (78.67%) patients (p-value = 0.021). Mean hospital stay after RIRS was 1.1 ± 0.09 days, while it was 2.3 ± 0.64 days after mini-PCNL (p-value < 0.001). Two (2.67%) patients in the mini-PCNL group developed bleeding postoperatively. The stone clearance rate in older patients (51 to 80 years) was significantly higher in the mini-PCNL group than RIRS group. Similarly, the stone clearance rate in female patients and in patients with larger stones (16 to 20 mm) was found to be higher in mini-PCNL group as compared to the RIRS group. Conclusion This study concluded that both mini-PCNL and RIRS are safe and efficient techniques for treating lower pole kidney stones with a size of 11-15 mm. However, mini-PCNL has a higher stone clearance rate compared to RIRS in the treatment of stones larger than 15 mm in size. This study further suggested that patients treated with mini-PCNL had a longer hospital stay compared to patients treated with RIRS.