Comparison of retrograde intrarenal surgery and mini-percutaneous nephrolithotomy in management of lower-pole renal stones with a diameter of smaller than 15 mm

Safety of flexible ureteroscopic lithotripsy with 365 μm fibers of Ho: YAG laser: a short-term follow-up

Our previous study first reported the efficacy of FURL using 365 μm fibers with holmium: yttrium aluminum garnet (Ho: YAG) laser lithotripsy. This study evaluates the 16-week safety of this procedure. A prospective cohort study was conducted, and the clinical characteristics of patients who underwent FURL using 365 μm fibers with Ho: YAG laser were retrospectively collected. Descriptive statistics were reported, and logistic regression analysis was conducted to identify risk factors influencing the stone-free rate (SFR). Infection-related laboratory parameters, including white blood cell count (WBC), procalcitonin (PCT), and C-reactive protein (CRP), were collected. Regression analysis was conducted to identify risk factors for the development of urosepsis post-surgery. Additionally, a 16-week follow-up was conducted in outpatient clinics, and kidney function was assessed. A total of 274 patients participated in this study. The 4-week stone-free rate (SFR) following FURL with 365 μm fibers of Ho: YAG laser was significantly associated with stone size and composition. No severe complications were observed following FURL procedures. There were no significant differences in white blood cell count (WBC), C-reactive protein (CRP), and procalcitonin (PCT) in peripheral blood before and after FURL procedures. Urosepsis was diagnosed in 1.82% of patients. Preoperative white blood cell count (WBC) in urine and preoperative urine culture results were identified as significant risk factors. Kidney function remained stable at 4 and 16 weeks following FURL. This prospective cohort study demonstrated the high safety of FURL with 365 μm fibers of Ho: YAG laser, as infection-related parameters during the perioperative period showed no significant differences, and kidney function remained stable throughout the 16-week follow-up.

Efficacy and safety of minimally invasive percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of upper urinary tract stones (> 1 cm): a systematic review and meta-analysis of 18 randomized controlled trials

BACKGROUND

The advantages and disadvantages of retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (mPCNL) for treatment of upper urinary tract calculi have not been conclusively determined.

METHODS

In this meta-analysis, We comprehensively evaluated the performance of the two surgical approaches in treatment of upper urinary calculi. We searched the Pubmed, Embase, Cochrane and Web of science databases for randomized controlled trial (RCT) articles on RIRS and mPCNL upto December 2022. Data were extracted by two independent reviewers and subjected to the meta-analysis using the Stata 15.1 software (StataSE, USA).

RESULTS

A total of 18 eligible RCTs involving 1733 patients were included in this study. The meta-analysis revealed that mPCNL of 1-2 cm or 2-3 cm stones had a higher stone clearance rate (RR:1.08, 95%CI (1.03, 1.14), p = 0.002) and shorter operation time (WMD : -10.85 min, 95%CI (-16.76, -4.94), p<0.001). However, it was associated with more hospital stay time (WMD :1.01 day, 95%CI(0.53, 1.5), p<0.001), hemoglobin drops (WMD :0.27 g/dl, 95%CI (0.14, 0.41), p<0.001), blood transfusion rate (RR:5.04, 95%CI(1.62, 15.65), p = 0.005), pain visual analogue score (WMD:0.75, 95%CI (0.04, 1.46), p = 0.037), hospital costs (SMD :-0.97, 95%CI (-1.19, -0.76), p<0.001) and major complications (RR:1.89, 95%CI(1.01, 3.53), p = 0.045).

CONCLUSION

Therefore, in terms of surgical effects and operation time, mPCNL is superior to RIRS, but is inferior with regards to other perioperative parameters. These factors should be fully considered in clinical decision making.

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.

Mini-Perc for Renal Stones-A Single Center Experience and Literature Review

AIM

The aim of this study was to analyze the outcomes of miniaturized nephrolithotomy (mini-perc) in the management of renal stones with a diameter smaller than 20 mm.

MATERIALS AND METHODS

We retrospectively reviewed the records of 102 patients who underwent mini-perc between March 2015 and March 2020 in our department. The primary objective was the stone-free rate, but we also analyzed the retreatment rate, complications, hospital stay, operative time and reduction in hemoglobin level. All these patients had this technique as their first-line treatment, in a prone position, using a 16 Fr sheath size. Data were compared to a series of patients from the literature, treated with conventional PCNL.

RESULTS

The patients had calculus limited to either a single calyx or just extending to the renal pelvis, and stone size was less than 20 mm in its maximal dimension. The intrarenal stone location was in the upper calyx in 7 cases, middle calyx in 20 cases and lower calyx in 46 cases, and there were 29 patients with renal pelvis stone. The male to female ratio was 1.5:1, and the median age was 48.4 years. The average stone size was 17.4 mm in diameter (ranging between 9 and 20 mm) and all cases underwent Ho-YaG laser lithotripsy, ballistic energy and combined ultrasonic and ballistic lithotripsy. At the end of the procedure, an antegrade double J stent was placed under fluoroscopy for a maximum of 2 weeks in 42 cases, while 9 cases needed a nephrostomy tube 12-14 F. A total of 51 cases were totally tubeless. Our median operative time was 61 min (ranging from 35 to 75 min). The median hospitalization stay was 3.8 days. The stone free rate was 90.1% after one procedure, only nine (8.8%) cases needed a "second look" flexible ureteroscopy, and the final stone-free rate was 98% (absence of detectable calculi on ultrasound, KUB or non-contrast CT scan). The overall complication rate was 6.86% (Clavien classification I-57.14%; II-28.5%; III-14.2%), while no Clavien IV or V complications were reported. No patient required a blood transfusion, and mean hemoglobin loss was 0.81 mg/dL. Overall, our results are better than similar data for conventional PCNL in the literature.

CONCLUSIONS

The "mini-perc" technique is an effective procedure for the treatment of the renal lithiasis that is less or equal to 2 cm. The results demonstrated that this minimally invasive technique is associated with a higher stone-free rate and minimal complications.

Comparison Between Percutaneous Nephrolithotomy and Retrograde Flexible Nephrolithotripsy in Obese Patients with 2 - 4 cm Renal Stones

Background: Nowadays, because of remarkable advancements in retrograde intrarenal surgery (RIRS), modest attention toward this procedure as the second or alternative choice for renal stones treatment has been drawn. Objectives: In the present study, we compared RIRS and percutaneous nephrolithotomy (PCNL) outcomes in treating obese patients with 2 - 4 cm renal stones. Methods: Eighty-two patients who underwent PCNL (n = 40) and RIRS (n = 42) between June 2015 and December 2018 at the Department of Urology of Sina Hospital were enrolled in our retrospective cohort study. Results: After the first surgery session, stone-free rates for the RIRS group were 92.9% and for the PCNL group was 95% (P value = 0.52). The mean operation time for the RIRS and PCNL groups were 71.6 ± 11 and 93.3 ± 12.2, respectively (P < 0.001). The hospitalization stay for all of the PCNL group was more than 1 day (mean = 2.5 days); however, that for the majority of the RIRS group was less than 1 day (P < 0.001). The analgesic use in the RIRS group was significantly lower than in the PCNL group (9.0 ± 5.5, 61.8 ± 13.6, respectively; P < 0.001). The overall complication rates were higher in the RIRS group. However, none of them were statically significant (P > 0.05). Conclusions: According to satisfactory outcomes obtained in the RIRS groups, it can be concluded that RIRS can be applied as an alternative or even the first choice in obese patients with 2 - 4 cm renal stones.

Super-mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery (RIRS) in the management of renal calculi ≤ 2 cm: a propensity matched study

OBJECTIVE

To compare the effectiveness and safety of Super-Mini PCNL (SMP) and Retrograde Intrarenal Surgery (RIRS) in the management of renal calculi ≤ 2 cm.

PATIENTS AND METHODS

A prospective, inter-institutional, observational study of patients presenting with renal calculi ≤ 2 cm. Patients underwent either SMP (Group 1) or RIRS (Group 2) and were performed by 2 experienced high-volume surgeons.

RESULTS

Between September 2018 and April 2019, 593 patients underwent PCNL and 239 patients had RIRS in two tertiary centers. Among them, 149 patients were included for the final analysis after propensity-score matching out of which 75 patients underwent SMP in one center and 74 patients underwent RIRS in the other. The stone-free rate (SFR) was statistically significantly higher in Group 1 on POD-1 (98.66% vs. 89.19%; p = 0.015), and was still higher in Group 1 on POD-30 (98.66% vs. 93.24%, p = 0.092) SFR on both POD-1 and POD-30 for lower pole calculi was higher in Group 1 (100 vs. 82.61%, p = 0.047 and 100 vs 92.61% p = 0.171). The mean (SD) operative time was significantly shorter in Group 1 at 36.43 min (14.07) vs 51.15 (17.95) mins (p < 0.0001). The mean hemoglobin drop was significantly less in Group 1 (0.31 vs 0.53 gm%; p = 0.020). There were more Clavien-Dindo complications in Group 2 (p = 0.021). The mean VAS pain score was significantly less in Group 2 at 6 and 12 h postoperatively (2.52 vs 3.67, 1.85 vs 2.40, respectively: p < 0.0001), whereas the mean VAS pain score was significantly less in Group 1 at 24 h postoperatively (0.31 vs 1.01, p < 0.0001). The mean hospital stay was significantly shorter in Group 1 (28.37 vs 45.70 h; p < 0.0001).

CONCLUSION

SMP has significantly lower operative times, complication rates, shorter hospital stay, with higher stone-free rates compared to RIRS. SMP is associated with more early post-operative pain though.

Size Distribution of Fragments by High-power Holmium Laser Lithotripsy in MiniPCNL with Suction

PURPOSE OF REVIEW

Data are lacking on distribution of size of fragments created with the laser lithotripsy, stone density, and composition. Dust (< 1 mm) and small fragments (1-3 mm) may be too small to be efficiently removed with forceps compared to larger fragments (> 3 mm). We aim to report the size distribution of fragments formed during holmium laser lithotripsy.

RECENT FINDINGS

One hundred ten patients with renal calculi < 3 cm underwent miniPCNL using ClearPetra sheath (Well Lead Medical Co., China) with controllable irrigation and suction system that minimizes fragment dispersion and maximizes fragment aspiration. Moses holmium laser (Lumenis INC, Israel) was used with predefined laser energy settings for lithotripsy. Proportion of fragment size < 1 mm was 46.36 ± 16.68%, 1-3 mm was 28.18 ± 10.01%, and > 3 mm was 25.19 ± 16.18% for the entire cohort. Complete stone clearance at 48 h was achieved in 77.3% cases. The remaining 22.7% patients had complete clearance at 1-month follow-up CT. In all the stone density, volume, and composition groups, majority of fragments created were either < 1 mm or 1-3 mm. Only 25% fragments were > 3 mm that would get aspirated out through the sheath with suction or could be retrieved with forceps. The combination of a high-power holmium laser and suction would help in complete stone clearance with effective aspiration of smaller stone fragments and dust simultaneously during lasing.

Comparison stone-free rate and effects on quality of life of percutaneous nephrolithotomy and retrograde intrarenal surgery for treatment of renal pelvis stone (2–4 cm)

Objectives:

The aim of our study was to compare the effects on quality of life (QoL) and stone-free rate (SFR) of percutaneous nephrolithotomy (PNL) and retrograde intrarenal surgery (RIRS) in patients with renal stones 2-4cm.

Materials and methods:

A total of 102 patients with renal pelvis stones were enrolled in this prospective controlled study, of which 52 were performed RIRS and 50 with PNL. The QoL was evaluated by using Short From-36 pre- and post-operatively. Also, the surgical data of all patients during and after the operations were compared between the 2 groups.

Results:

The mean age, body mass index, stone size and density of the patients in the 2 groups were statistically similar (p > 0.05). The SFR of PNL and RIRS were found 94% (47/50) and 73% (38/52), respectively (p < 0.01). There were no statistically differences between operation times, minor complication rates and Short From-36 scores of the 2 groups. Hospitalization times were 1.13 ± 0.34days for RIRS and 2.9 ± 5.7days for PNL (p < 0.05). While the blood transfusion rate of PNL group was 8% (4/50), none patient was made blood transfusion in RIRS.

Conclusions:

The results of our study show that the blood transfusion rates and hospitalization times of RIRS group are significantly lower than PNL for management of renal pelvis stone 2-4cm. Despite these advantages of RIRS, the SFR is significantly lower than PNL for these stones. The effects on QoL of the both interventions before and after surgery were similar.

Miniaturized percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of lower pole renal stones

OBJECTIVES

Miniaturization of percutaneous nephrolithotomy techniques have led to their increased consideration for lower pole renal stones that can prove more challenging to reach using retrograde intrarenal surgery. The objectives of the present study were to evaluate and compare the outcomes of miniaturized percutaneous nephrolithotomy (miniPCNL) and retrograde intrarenal surgery (RIRS) for the treatment of lower pole renal stones.

MATERIALS AND METHODS

A retrospective study was performed in two academic urology departments between January 2016 and June 2019. Patients presenting with one or multiple stones of the lower calyx and/or renal pelvis, between 10 and 40mm based on CT-scan treated by miniPCNL or RIRS were included.

RESULTS

In all, 115 miniPCNL and 118 RIRS procedures were included. The rate of patients with no significant residual fragment (stone free rate) after the first procedure was higher in the miniPCNL group (69% vs. 52% P=0.01), especially for stones>20mm (63% vs. 24% respectively, P<0.001) and stones with a density≥1000HU (69% vs. 42% respectively, P=0.009). The higher stone free rate of miniPCNL was confirmed in multivariate analysis, adjusting for stone size and number of stones, OR 4.02 (95% CI 2.08-8.11, P<0.0001). The overall postoperative complication rate was higher in the miniPCNL group than in the RIRS group (23% vs. 11%, P=0.01). A second intervention for the treatment of residual fragments was necessary for 9.6% of patients in the miniPCNL group versus 30.5% of patients in the RIRS group (P<0.001). Pre-stenting rate and duration of ureteral drainage (2 [1-8] vs. 25 days [7-37], P<0.001) were lower in the miniPCNL group.

CONCLUSIONS

The stone free rate was higher after miniPCNL, especially for stones>20mm and with a density>1000 HU, but was associated with a higher risk of postoperative complications and a longer hospital stay. RIRS resulted in fewer complications at the cost of a higher retreatment rate and longer ureteral stenting.

LEVEL OF EVIDENCE

3.

The comparison of perioperative outcomes between percutaneous nephrolithotomy and retrograde intrarenal surgery in elderly patients

OBJECTIVES

In this study, we aimed to compare the outcomes and complication rates of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) in elderly patients.

MATERIALS AND METHODS

Between April 2011 and January 2020, patients who underwent PCNL and RIRS for renal stone in elderly patients were retrospectively evaluated. The two groups' perioperative values, stone-free rates and complication rates were compared. Post-operative complications were noted according to the Clavien scoring system.

RESULTS

There were 89 and 72 patients in the PCNL and RIRS group respectively. The median age was 67 years in both the groups (P = .192). The stone size were 22.2 ± 3.5 mm and 19.9 ± 7.1 mm in the PCNL and RIRS group, respectively (P = .082). Stone-free rates were significantly higher in PCNL group (P = .021, P = .034). Also we found that overall complication and major complication rates were significantly higher in PCNL group (P = .016, P = .029).

CONCLUSION

Despite there was higher stone clearance in PCNL, the complication rates were higher compared with RIRS. So RIRS might be a safe alternative treatment method to PCNL in older patients.

Miniaturized Ambulatory Percutaneous Nephrolithotomy Versus Flexible Ureteroscopy in the Management of Lower Calyceal Renal Stones 10-20 mm: A Propensity Score Matching Analysis

OBJECTIVE

To evaluate the efficacy of ambulatory mini percutaneous nephrolithotomy (Mini-PCNL) and flexible ureteroscope (F-URS) in treating 10-20 mm lower calyceal stones using propensity score matching analysis (PSM).

PATIENTS AND METHODS

A retrospective analysis of 136 adult patients that underwent Mini-PCNL or F-URS for a single lower calyx calculus. Participants that underwent F-URS were allocated to Group I, while those who underwent Mini-PCNL were assigned to Group II. Patients were discharged on the same day and followed up by CT after 3 months. Both groups were matched by stone size and density using propensity stone matching (PSM) and the matched group were further compared.

RESULTS

Before matching, there were statistical differences in stone size (P = .02), preoperative hydronephrosis (P = .004), and Hounsfield Unit (P = .04) between both groups. A logistic regression model was created between independent variables such as stone size and density. The new groups following PSM were statistically similar in terms of age, BMI, stone size, and HFU (P = .43, P = .74, P = .49, P = .36). The stone-free rates after PSM was not significantly higher in the Mini-PCNL group than the F-URS group (91.7% vs 81.7%, respectively P = .1) while the operative time for the F-URS group was significantly shorter than the Mini-PCNL group 54 (49-64.3) minutes vs 68.2 (62-73.5) minutes, respectively, P = .045.

CONCLUSION

Ambulatory Mini-PCNL and F-URS have a comparable hospital stay, stone-free rates, and complication rates for treating lower calyceal stones 10-20 mm. Both techniques may be considered acceptable treatment options, with a prolonged operative time in Mini-PCNL.

A systematic review and meta-analysis of minimally invasive vs. standard percutaneous nephrolithotomy in the surgical management of renal stones

The present study aimed to assess current evidence on the effectiveness and safety of minimally invasive vs. standard percutaneous nephrolithotomy (PCNL) in the management of renal stones. A systematic search of electronic databases, which included PubMed, EMBASE and the Cochrane Library up to May 2019 was performed. Using Review Manager statistical software (version 5.3), primary outcomes, including stone-free rates (SFRs), were evaluated. Meanwhile, analysis was also performed to compare secondary outcomes, such as peri- and postoperative complications and operative data. Fourteen studies involving 1,611 patients with renal stones were analyzed based on the inclusion criteria. On the basis of the present analysis, mini percutaneous nephrolithotomy (MPCNL) was proven to have non-inferior clinical efficacy with respect to the SFR compared with PCNL [odds ratio (OR)=1.10; 95% confidence interval (CI), 0.84-1.44; P=0.48]. In addition, the meta-analysis showed that MPCNL had a significantly lower hemoglobin decrease [mean difference (MD)=-0.68; 95% CI, -1.05 to -0.31; P=0.0003] and fewer blood transfusions (OR=0.36; 95% CI, 0.18-0.71; P=0.003) compared with PCNL. Moreover, the MPCNL group had a shorter inpatient stay (MD=-0.81; 95% CI, -1.55 to -0.08; P=0.03) compared with the PCNL group. However, the overall evidence was insufficient to suggest a statistically significant difference in the adverse event profile for MPCNL compared with PCNL. The present meta-analysis indicates that MPCNL is an effective method for treating renal stones. Compared with PCNL, MPCNL not only has similarly high SFRs but is also associated with less blood loss, fewer blood transfusions, more favorable recovery time and shorter inpatient stays. However, the findings of the present study should be further confirmed by well-designed prospective randomized controlled trials with a larger patient series.

Acute kidney injury following supine mini-PNL versus retrograde intrarenal surgery in patients with renal stones < 3 cm: a prospective comparative study

Background

The purpose of the current study was to prospectively compare mini-PNL and RIRS for development of acute kidney injury (AKI), success, and complication rates in a cohort of patients with kidney stones less than 3 cm.

Methods

In this prospective study, data of 60 consecutive patients underwent mini-PNL (n = 31) or RIRS (n = 29) was investigated. Urinary NGAL levels were measured preoperatively and at postoperative 6th hour to evaluate AKI. Success and complication rates were also compared.

Results

The mean stone size was significantly higher in the mini-PNL group (24.6 mm vs. 18.2 mm, p = 0.02). The mean postoperative NGAL levels were 45.6 ± 12.4 and 48.1 ± 13.6 for the mini-PNL and RIRS groups, respectively. The increase was statistically significant for both groups (p: 0.01). The difference between the two groups for mean postoperative NGAL measurements was not statistically significant (p = 0.47). The SFR was significantly higher in the mini-PNL group (96.7% vs. 79.3%, p = 0.04). The complication rates were similar for the two groups (p = 0.99). The mean duration of operation was 48.2 ± 22.5 min in the mini-PNL group and 62.6 ± 18.1 min in the RIRS group (p = 0.03). The median duration of hospitalization was 1 day for both groups.

Conclusions

In patients with renal stones < 3 cm in diameter, mini-PNL in supine position provides higher SFR and shorter operative times with similar rates of complications and AKI when compared with RIRS. Mini-PNL should be considered as the primary treatment option together with RIRS for renal stones and should not be ruled out for being a more invasive option.

A clinical experience of thulium fibre laser in miniperc to dust with suction: a new horizon

PURPOSE

To report safety and efficacy of mini-PCNL with suction attached to sheath combined with high-power Thulium Fibre laser (TFL). The secondary aim was to evaluate optimal laser settings for maximum stone dusting.

MATERIALS AND METHODS

Prospective, single arm study was conducted from June 2019-December 2019 using miniPCNL with suction and TFL in 54 patients with renal stones < 3 cm. Stone fragments for each laser setting were independently retrieved and segregated according to size(< 1 mm,1-3 mm, > 3 mm) and weighed. Xray/CT scan imaging was performed in all patients within 48 h and 30 days to assess stone clearance. Optimal laser settings were evaluated for maximum dusting.

RESULTS

Mean stone size was 18.32 ± 6.37 mm, volume was 2337.75 ± 1996.84mm³ and stone density was 1300.55 ± 435.32 HU. Total operative time was 39.85 ± 20.52 min, laser time was 10.08 ± 7.41 min and stone fragmentation rate was 5.02 ± 3.93 mm³/s. The procedure was completely tubeless in 37.04%, nephrostomy tube in 37.04% and DJ stent placed in 25.92%. Postoperatively, three patients had urinary infection (Clavien 2). Complete stone clearance at 48 h was achieved in 35 (64.8%) cases. 19 patients (35.2%) who had residual fragments at 48 h, had 100% clearance at one month on CT/Xray KUB.

CONCLUSIONS

MiniPCNL using a nephrostomy sheath with suction along with high power Thulium Fibre Laser is safe and effective modality for lithotripsy. An initial laser setting of 0.2 J and 125-200 Hz was optimal for maximum dusting and simultaneous aspiration. Randomized comparative studies with other energy sources are being considered.

Percutaneous nephrolithotomy versus flexible ureteroscopic lithotripsy in the treatment of upper urinary tract stones: a meta-analysis comparing clinical efficacy and safety

BACKGROUND

Upper urinary tract stones is the most common diseases in urology. Percutaneous nephrolithotomy (PCNL) and ureteroscopic lithotripsy (fURL) are common treatment, but both their efficacy and safety are controversial. Thus we aim to evaluate the efficacy and safety of PCNL and fURL in the treatment of upper urinary tract stones, providing a reference for clinical work.

METHODS

PubMed, Web of Science, Embase and CNKI were searched through Apr. 1, 2019 to identify eligible studies. Data were analyzed by using RevMan 5.3 and Stata 12.0 software. Pooled relative risks (RRs) or weighted mean difference (WMD) with 95% confidence intervals (CIs) were calculated using fixed or random effects methods. Publication bias and sensitivity analysis were performed.

RESULTS

Four randomized controlled trials (RCTs), fifteen cohort studies involving 1822 patients were included. Stone-free rate of PCNL was significantly high than that of fURL (RR: 1.07; 95% CI: 1.03, 1.12; P = 0.0004). The decline of hemoglobin in PCNL was significantly high than that of fURL (WMD: 1.07; 95% CI: 0.54, 1.61; P < 0.0001). The number of blood transfusion was significantly greater in the PCNL compared to the fURL (RR: 5.04; 95% CI: 1.78, 14.24; P = 0.002). The incidence of postoperative bleeding or hematuria showed greater significantly difference in the PCNL compared to the fURL (RR: 2.72; 95% CI: 1.55, 4.75; P = 0.0005). Operation time, fever, infection, perforation, requiring drug analgesia was not significantly different between two surgical procedures.

CONCLUSIONS

In the treatment of upper urinary tract stones, the stones clearance rate of PCNL is higher than fURL, and the safety of fURL is higher than PCNL.

Microultrasonic Probe Combined with Ultrasound-Guided Minipercutaneous Nephrolithotomy in the Treatment of Upper Ureteral and Renal Stones: A Consecutive Cohort Study

Objectives: We conduct a study to assess the outcome of microultrasonic probe combined with ultrasound (US)-guided minipercutaneous nephrolithotomy (PCNL) for upper ureteral and renal stones. Patients and Methods: Data of 119 patients (123 kidney units) who underwent microultrasonic lithotripsy combined with mini-PCNL were retrospectively reviewed. The group included 96 men and 23 women. All procedure of puncture and dilatation were guided by US solely. Data were analyzed by SPSS. Results: The mean operation time was 32.6 minutes (range, 10-110 minutes). The mean time of lithotripsy and stone removal was 14.5 minutes (3-100 minutes). The mean postoperative length of stay was 2.7 days (1-7 days). Besides, stone-free rate (SFR) at discharge was 95.9% (118/123). The mean hemoglobin drop was 11.6 mg/dL (range 1-26 mg/dL). Grades I, II, and IIIa complications were observed in four, one, and one patients, respectively. Subgroup analysis was done to compare the outcomes of 20 mm or less vs 21 mm or more calculi. There was a longer operation duration (40 vs 29 minutes) and lower SFR in the 21 mm or more calculi subgroup. Conclusions: Microultrasonic probe combined with US-guided mini-PCNL is an effective and safe procedure to treat patients with upper ureteral and renal stones with higher SFR but lower complications.

Postoperative renal functional changes assessed by 99mTc-DTPA scintigraphy and predictive factors after miniaturized percutaneous nephrolithotomy and retrograde intrarenal surgery: An observational 1-year follow-up study

Purpose

We evaluated the comparative effect of miniaturized percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) on perioperative kidney function by use of diethylenetriamine penta-acetic acid (^99mTc-DTPA) scintigraphy and identified significant predictors associated with deterioration or amelioration of renal function after surgery.

Materials and Methods

All 70 patients who underwent mini-PCNL or RIRS between 2012 and 2016 were monitored by ^99mTc-DTPA scintigraphy preoperatively. Patients with abnormal renal function were monitored from 3 to 12 months postoperatively. Logistic regression analyses were conducted to estimate the predictors of aggravated renal dysfunction and improvement.

Results

The difference in preoperative renal function between the contralateral and the operative side was >10% in 57 patients (81.4%). Among those in the group with abnormal renal function, 40 (70.2%), 10 (17.5%), and 7 (12.3%) patients showed stability, deterioration, and improvement in renal function at postoperative year 1, respectively. Functional changes did not differ according to the type of surgery. A high level of serum creatinine preoperatively (p=0.060) and a history of previous stone procedures (p=0.051) showed borderline significance for prediction of deterioration in renal function.

Conclusions

RIRS and mini-PCNL had similar effects and favorable outcomes on renal function during a 1-year follow-up period. High baseline serum creatinine levels and a history of procedures warrant careful attention.

Minimally invasive percutaneous nephrolithotomy versus retrograde intrarenal surgery in surgical management of upper urinary stones - A systematic review with meta-analysis

OBJECTIVE

The purpose of this study was to retrospectively assess the efficacy and safety of minimally invasive nephrolithotomy (MPCNL) versus retrograde intrarenal surgery (RIRS) in the management of upper urinary stones.

METHODS

A comprehensive literature review of articles that investigated the efficacy and safety of MPCNL and RIRS was conducted by systematically searching PubMed, EMBASE, and Cochrane Library in March 2019. Two reviewers searched the literature, independently extracted the data and evaluated the quality of the data according to the inclusion and exclusion criteria. A meta-analysis was performed by using Review Manager 5.3 software.

RESULTS

Eight randomized controlled trials (RCTs) involving 725 patients with upper urinary stones were analysed based on the inclusion criteria. While MPCNL has a better clinical efficacy than RIRS with respect to the stone-free rate (SFR) [RR = 1.11, 95% CI (1.05-1.17), p = 0.0005], MPCNL has a higher incidence of haematoma [RR = 3.09, 95% CI (1.44-6.66), p = 0.004] and longer hospitalization time [MD = 0.89 day, 95% CI (0.07-1.72), p = 0.04]. In addition, no significant difference in operative time [MD = 2.46 min, 95% CI (-17.99 to 22.92), p = 0.81] and postoperative pain score [MD = 0.74, 95% CI (-0.45 to 1.94), p = 0.22] were observed between the two methods. Overall, the evidence was insufficient to suggest a statistically significant difference in the adverse event profile for MPCNL compared with RIRS.

CONCLUSIONS

Our data suggest that MPCNL is an effective method for treating upper urinary stones, especially lower calyceal stones that are 1-2 cm in size. Compared to RIRS, MPCNL is associated with a longer hospital stay time and a higher incidence of haematoma. In addition, both methods have proven to be safe. Nevertheless, the findings should be further confirmed through well-designed prospective RCTs with a larger patient series.

Clinical efficacy and safety of flexible ureteroscopic lithotripsy using 365 μm holmium laser for nephrolithiasis: a prospective, randomized, controlled trial

PURPOSE

To compare the clinical efficacy and safety between the FURL with 365 μm and 200 μm holmium laser for treating nephrolithiasis.

MATERIALS AND METHODS

A prospective randomized controlled trial was performed including analysis of data from 200 patients with nephrolithiasis. A total of 180 patients were randomized into two groups according to 1:1 ratio. In the 365 μm holmium laser group, kidney stones were disintegrated into less than 2 mm fragments with a 365 µm holmium laser fiber with the settings of 30-45 W under direct visualization; in the control group, the conventional 200 μm holmium laser was used. Descriptive statistics and logistic regression analyses tested the association among operation time, stone-free rate (SFR) and incidence of complications.

RESULTS

Operation time in the FURL with 365 μm laser was significantly shortened and no significance was observed in the complication rate. Stone size and location were identified as two major confounding factors for the operation time and SFR. Moreover, the FURL using 365 μm laser showed less operation time for renal stones with the diameter between 1 and 2 cm, stones located in lower calyx and multiple calculi; stones larger than 2 cm and/or located in lower pole inclined to present better SFR using the FURL with 365 μm laser.

CONCLUSIONS

The FURL combined with 365 μm holmium laser is safer and highly efficacious for the management of nephrolithiasis when compared to conventional FURL procedures, especially for those located in lower pole and larger than 2 cm.

Changes in separate renal function in patients who underwent minimally invasive renal stone surgery according to the preoperative functional deterioration

The significant predictors for the postoperative deterioration of separate renal function after minimally invasive stone surgery were investigated in the present prospective and observational study. A total of 117 consecutive patients who underwent retrograde intrarenal surgery or mini-percutaneous nephrolithotomy for renal calculi >10 mm were included in the present study. Perioperative changes in separate renal function were evaluated with Technetium-99m-Diethylene TriaminePenta acetic acid scan prior to intervention and at postoperative 3 months. Based on the functional differences between bilateral renal units, deterioration of separate renal function was graded into the following three groups: normal deterioration (<10%), moderate deterioration (10–20%), and severe deterioration (>20%). A total of 46 patients had a normal separate renal function, while 71 (60.7%) showed abnormal separate function in the involved side, including 29 (24.8%) moderate and 42 (35.9%) severe deterioration. Postoperatively, 48 patients (41.0%) showed aggravation or no recovery of separate renal function. Of the 46 patients with normal separate function, only 9 patients (19.5%) showed postoperative aggravation. Patients with moderate and severe deterioration showed aggravation (n = 7, 24.1%) or no recovery of separate renal function (n = 32, 76.1%, P < 0.001). Preoperative severe deterioration of separate renal function was an independent significant predictor for the postoperative deterioration of renal function (OR: 9.09, 95% CI: 4.007–20.624, P < 0.001). Lower preoperative deterioration of separate renal function showed a high probability of functional recovery. Therefore, it is hypothesized that early intervention might be necessary in cases where the patient exhibits severe aggravation of renal function.

How to perform the dusting technique for calcium oxalate stone phantoms during Ho:YAG laser lithotripsy

BACKGROUND

To determine the most efficacious setting of Holmium:yttrium-aluminum-garnet (Ho:YAG) laser with a maximum power output of 120 W with in vitro phantom-stone dusting technique.

METHODS

A laser was used to treat two 4 × 3 × 3 mm³ sized phantom stones in 5 mL syringes with 1 mm-sized holes at the bottom. According to the pulse width (short 500, middle 750, long pulse 1000 μsec), maximal pulse repetition rates from 50 to 80 Hz were tested with pulse energy of 0.2, 0.4, 0.5, and 0.8 J. Six times of the mean dusting times were measured at each setting. Dusting was performed at continuous firing of the laser until the stones become dusts < 1 mm.

RESULTS

The mean Hounsfield unit of phantom stones was 1309.0 ± 60.8. The laser with long pulse generally showed shorter dusting times than short or middle pulse width. With increasing the pulse energy to 0.5 J, the dusting time decreased. However, the pulse energy of 0.8 J showed longer dusting times than those of 0.5 J. On the post-hoc analysis, the pulse energy of 0.5 J, long pulse width, and the repetition rates of 70 Hz demonstrated significantly shorter dusting times than other settings.

CONCLUSIONS

The results suggest that long pulse width with 0.5 J and 70 Hz would be the most efficacious setting for dusting techniques of plaster stone phantoms simulating calcium oxalate stones using the 120 W Ho:YAG laser.

Present indications and techniques of percutaneous nephrolithotomy: What the future holds?

The purpose of the review was to present the latest updates on percutaneous nephrolithotomy (PCNL) procedure in terms of indications and evolving techniques, and to identify the advantages and disadvantages of each modality. The data for this review were collected after a thorough PubMed search in core clinical journals in English language. The key words included “PCNL” and “PNL” in combination with “indications”, “techniques”, “review” and “miniaturized PCNL”. Publications relevant to the subject were retrieved and critically reviewed. Current European and American Urology Association Nephrolithiasis Guidelines were included as well. The indications for standard PCNL have been changed through the past decade. Despite evolution of the procedure, innovations and the development of new technical approaches, the indications for miniaturized PCNL have not been standardized yet. There is a need for well-constructed randomized trials to explore the indications, complications and results for each evolving approach. A continuous reduction of tract size is not the only revolution of the last years. There is constant ongoing interest in developing new efficient miniature instruments, intracorporeal lithotripters and sophisticated tract creation methods. We can summarize that, PCNL represents a valuable well-known tool in the field of endourology. We should be open minded to future changes in surgical approaches and technological improvements.

Urological technology: where will we be in 20 years' time?

Since prehistoric times, our understanding of urology has rapidly expanded. Whilst primitive urologists began by using urine as a therapeutic substance, modern urologists may find themselves removing a kidney remotely by driving a robotic arm, with seven degrees of movement, while using image overlay-augmented reality. This review provides an insight into the potential status of urological technology in 20 years' time, assessed through an analysis of developments in imaging, diagnostics, robotics and further technologies. A particular emphasis is given to the promising fields of minimally invasive techniques, nanotechnology and tissue engineering, which likely hold the key to a new era for urology.

Retrograde intrarenal surgery: An expanding role in treatment of urolithiasis

During the past 3 decades, the surgical management of kidney stones has undergone many technological advances and one is the development of the flexible ureteroscopy. The development of this instrument as well as ancillary equipment such as baskets, graspers, and others, and improvements in lithotripsy with Holmium: YAG laser have led to expand its indications with diagnostic and therapeutic management of medical issues of the upper urinary tract such as urolithiasis and urothelial tumors. The objective of this review is to describe its indications and results in the different scenarios for the treatment of urinary stones.

The "all-seeing needle" micro-PCNL versus flexible ureterorenoscopy for lower calyceal stones of ≤ 2 cm

The objectives of the study are to compare the safety and efficacy of "all-seeing needle" optical puncture system micro-percutaneous nephrolithotomy (micro-PCNL) and flexible ureterorenoscopy (FURS) for the treatment of lower calyceal stones of ≤ 2 cm and to determine the advantages and disadvantages of each. 116 patients in total with lower calyceal stones of ≤ 2 cm were randomly divided into two equal groups, "all-seeing needle" optical puncture system micro-PCNL and FURS. In both groups, holmium laser was utilized for lithotripsy. The perioperative parameters were compared between the two groups. Compared to the "all-seeing needle" micro-PCNL group, the mean operative time was significantly longer in the FURS group (P = 0.000). However, there was no significant difference between the two groups with respect to mean hemoglobin reduction (P = 0.087), complications (P = 0.731) and LOS (P = 0.856). The overall SFR of the "all-seeing needle" micro-PCNL group and FURS group was 84.5% (49/58) and 79.3% (46/58), respectively, without any significant difference between the groups (P = 0.469). For treating lower calyceal stones of ≤ 2 cm, the "all-seeing needle" micro-PCNL group had shorter operative time than FURS, while no significant differences between the two groups with respect to mean hemoglobin reduction, complications, LOS and SFR were found.

Skin to calyx distance is not a predictive factor for miniaturized percutaneous nephrolithotomy outcomes

Objective

To evaluate the predictive value of the distance from skin to calyx (SCD) on the outcome and complication rates of patients undergoing mPNL.

Materials and Methods

Patient’s charts, who had undergone mPNL between June 2012 and June 2015, were analyzed retrospectively. Patients who had a preoperative computerized tomography (CT) were enrolled into the study. Two separateurologists evaluated the CT scans and calculated the SCD defined as the distance between the skin and surface/lateral edge of the calyx, which was the preferred site of entry for percutaneous access. The average value of the two measurements was included inthe final analysis to avoid bias. The mean SCD was 75mm. According to the median SCD value, patients were divided into two groups: group 1 (SCD ≤75) and group 2 (SCD >75).

Results

A total of 140 patients and 130 patients were enrolled in groups 1 and 2, respectively. The mean operation time and the mean fluoroscopy time was significantly longer in group 2 (p:0.004 vs. p:0.021). The rate of blood transfusion was significantly higher in group 1 (6 patients). None of patientsin group 2required blood transfusion (p:0.017). Stone-free status after a single session of mPNL was 67.1% in group 1 and 75.4% in group 2 (p:0.112). After additional procedures, stone-free rates increased to 84.3% and 85.4% in group 1 and group 2, respectively (p:0.802).

Conclusion

Our study demonstrated that longer SCD was not a predictive factor for stone-free rates after mPNL. However, SCD over 75mm was associated with longer operation time and fluoroscopy time with lower rates of transfusion.

Small-calibre percutaneous nephrolithotomy (SC-PCNL). Therapeutic decision algorithm

INTRODUCTION

The progressive reduction in the calibre of the tract in percutaneous kidney surgery to the point of miniaturisation has expanded its use to smaller stones that until now have been treated with extracorporeal shock wave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS).

OBJECTIVE

To provide an update on the various techniques of small-calibre nephrolithotomy (SC-PCNL) analyse their efficacy, safety and indications and determine their degree of implantation at this time.

MATERIAL AND METHODS

We performed a review in PubMed of Spanish and English medical literature on the various techniques of SC-PCNL.

RESULTS

The use of SC-PCNL has reduced the morbidity associated with standard PCNL, particularly bleeding, and has enabled tubeless nephrolithotomy with greater safety. There are various techniques with blurred terminology (Miniperc, Microperc, Mini-microperc, Ultraminiperc), which differ in terms of gauge employed and in certain technical aspects that require their indications be specified. Currently, SC-PCNL competes with techniques that are less invasive than standard PCNL such as ESWL and the RIRS in treating small stones, but the role of SC-PCNL is still not sufficiently understood and continues to be the subject of debate.

CONCLUSIONS

The indications for PCNL are expanding to small stone sizes due to the miniaturisation of the technique. PCNL competes in this field with ESWL and RIRS. Larder studies are needed to establish the specific indications for PCNL in treating nephrolithiasis.

A prospective randomized comparison among SWL, PCNL and RIRS for lower calyceal stones less than 2 cm: a multicenter experience : A better understanding on the treatment options for lower pole stones

PURPOSE

To prospectively evaluate the efficacy and safety of RIRS, SWL and PCNL for lower calyceal stones sized 1-2 cm.

MATERIALS AND METHODS

Patients with a single lower calyceal stone with an evidence of a CT diameter between 1 and 2 cm were enrolled in this multicenter, randomized, unblinded, clinical trial study. Patients were randomized into three groups: group A: SWL (194 pts); group B: RIRS (207 pts); group C: PCNL (181 pts). Patients were evaluated with KUB radiography (US for uric acid stones) at day 10 and a CT scan after 3 months. The CONSORT 2010 statement was adhered to where possible. The collected data were analyzed.

RESULTS

The mean stone size was 13.78 mm in group A, 14.82 mm in group B and 15.23 mm in group C (p = 0.34). Group C compared to group B showed longer operative time [72.3 vs. 55.8 min (p = 0.082)], fluoroscopic time [175.6 vs. 31.8 min (p = 0.004)] and hospital stay [3.7 vs. 1.3 days (p = 0.039)]. The overall stone-free rate (SFR) was 61.8% for group A, 82.1% for group B and 87.3% for group C. The re-treatment rate was significantly higher in group A compared to the other two groups, 61.3% (p < 0.05). The auxiliary procedure rate was comparable for groups A and B and lower for group C (p < 0.05). The complication rate was 6.7, 14.5 and 19.3% for groups A, B and C, respectively.

CONCLUSIONS

RIRS and PCNL were more effective than SWL to obtain a better SFR and less auxiliary and re-treatment rate in single lower calyceal stone with a CT diameter between 1 and 2 cm. RIRS compared to PCNL offers the best outcome in terms of procedure length, radiation exposure and hospital stay. ISRCTN 55546280.

Retrograde intrarenal surgery for renal stones - Part 2

Retrograde intrarenal surgery (RIRS) has become an effective and safe treatment modality in the management of urinary system stone disease. Recent developments and innovations in the flexible ureterorenoscope and auxiliary equipment have made this procedure easier and more effective with increased success rates. RIRS can be used as a primary treatment in patients with renal stones smaller than 2 cm, prior unsuccessful shock wave lithotripsy, infundibular stenosis, renoureteral malformation, skeletal-muscular deformity, bleeding diathesis and obese patients. In the second part of this detailed review for RIRS, effect of stone composition on success rate, preoperative assessment of stone-free rate, the cost of this modality, education for RIRS, fluoroscopy use, the current role of RIRS in the treatment of various urolithiasis types and special conditions, and combined treatment methods are discussed with up-to-date literature.

Is standard percutaneous nephrolithotomy still the standard treatment modality for renal stones less than three centimeters?

OBJECTIVE

The aim of study was to compare the efficiency and safety of standard percutaneous nephrolithotomy (sPNL) and miniaturized percutaneous nephrolithotomy (mPNL) in lower calyx and/or pelvic stones smaller than three centimeters.

MATERIAL AND METHODS

From October 2010 to August 2015, 108 mPNL and 176 sPNL procedures were performed for renal stones smaller than three cm and located in the lower calyx and/or renal pelvis. All patients were evaluated preoperatively with intravenous pyelography and/or computed tomography. Intraoperative parameters, post-operative results and complications were recorded. Postoperative success was defined as complete stone clearance and/or clinically insignificant residual fragments at 3^rd month.

RESULTS

Preoperative characteristics were similar between sPNL and mPNL groups except previous renal stone operation history and gender. The mean operation time was significantly shorter in the sPNL group (p<0.001). The mean hemoglobin drop was significantly less in the mPNL group (p=0.001), we found a 1.27±1.4 and 0.5±1.3 decrease in mean hemoglobin levels (mg/dL) in the sPNL and mPNL groups, respectively. Transfusion rate was 1.9% in mPNL and 5.6% in sPNL groups, and the difference was statistically significant (p=0.048). Only one patient in the sPNL group needed angiography and embolization. Postoperative JJ stent insertion rate was significantly higher in the mPNL group (p=0.03).

CONCLUSION

Both sPNL and mPNL are safe and effective surgical procedures for lower calyx and/or pelvis stones smaller than 3 cm. However, use of smaller caliber instruments was associated with a lesser hemoglobin drop and need for transfusion.

Minimally Invasive Percutaneous Nephrolithotomy versus Retrograde Intrarenal Surgery for Upper Urinary Stones: A Systematic Review and Meta-Analysis

Minimally invasive percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) are both alternatives for PCNL to treat renal calculi. This study is aimed at comparing the stone-free rate (SFR) and other surgery parameters of two approaches for treating upper urinary calculi. We performed this meta-analysis in September 2016 by searching studies about mini-PCNL and RIRS for treating upper urinary calculi in various databases, and RevMan v.5.3 was applied. Three randomized controlled trials and ten nonrandomized trials were included, involving a total of 1317 patients. Meta-analysis showed that mini-PCNL group led to a higher SFR [odds ratio: 1.96; 95% confidence interval: 1.46–2.64; P < 0.00001] but brought a larger postoperative decrease in hemoglobin levels compared with RIRS. RIRS provided a shorter hospital time. There was no significant difference in operation time. Higher postoperative complications were detected in the mini-PCNL, but the difference was not significant. Grade I and III complications did not vary between two procedures, but grade II complications were of lower incidence in RIRS group. In the light of these results, compared with RIRS, mini-PCNL provided significantly higher SFR and efficiency quotient for managing calculi; however, it resulted in higher incidence of postoperative complications, larger hemoglobin drops, and longer hospital stay.

Use of a Novel Flexible Mini-nephroscope in Minimally Invasive Percutaneous Nephrolithotomy

OBJECTIVE

To assess the feasibility and safety of a novel flexible mini-nephroscope in minimally invasive percutaneous nephrolithotomy (PCNL). Presumably, limiting the size and number of tracts during PCNL has the potential of decreasing the morbidity of the procedure. We present our experience with this new technique.

MATERIALS AND METHODS

A retrospective analysis of patients with multiple kidney stones treated with mini-PCNL combined with a novel flexible mini-nephroscope was performed. Minimally invasive PCNL was done with rigid 12 F MIP-M nephroscope, followed by flexible mini-nephroscopy for smaller stones in other inaccessible calyces. Record was made of the operating time, stone-free rates, postoperative pain, morbidity, hospital stay, time to recovery, complication rates, and ancillary procedures. Matched-pair analysis was done with cases operated by flexible ureteroscopy performed with Flex X-2 or Flex X-c scope.

RESULTS

Twenty-five patients in the study group were matched with 25 cases from the flexible ureteroscopy group. Both groups were comparable in terms of age, laterality, and mean composite stone burden. The mean operating time was 40.1 ± 10.6 minutes in the mini-PCNL group and 51.2 ± 8.8 minutes in the flexible ureteroscopy group. Mean hospital stay was similar in both groups. The primary stone clearance rate of 92% (23 of 25) in the mini-PCNL group was better than the clearance rate of 80% (20 of 25) in the flexible ureteroscopy group. Eight percent in the mini-PCNL group required ancillary procedures as compared with 20% of cases in the flexible ureteroscopy group. Postoperative pain and analgesia requirement in these patients was minimal. There were no significant complications.

CONCLUSION

Flexible mini-nephroscope is an effective adjuvant to minimally invasive PCNL in achieving high clearance rate with minimum morbidity.

Miniaturization of percutaneous nephrolithotomy Smaller, but better?

PURPOSE OF REVIEW

Miniaturized percutaneous nephrolithotomy (PCNL) procedures have reached big popularity in the past years. Following the idea that decreasing the diameter of the instruments would decrease the complication rate instruments with outer diameter down to 4,8 Fr was established. In this review, we want to take a critical insight of the most popular miniaturized procedures, regarding the key advantages and disadvantages of the miniaturized instruments.

RECENT FINDINGS

For all techniques displayed, a number of studies are available to support their effectivity in the given range of indication. Naturally, the body of evidence for M-sized instruments is largest, as it exists in the armamentarium since long, whereas studies comparing small or extrasmall and extraextrasmall to standard or among each other are rare. However, large studies comparing miniaturized procedures with conventional PCNL in randomized controlled fashion are still lacking, too.

SUMMARY

Miniaturization and attending developments such as ultrasonographic-guided puncture, single step dilatation of the tract, low irrigation pressure in open systems and a tubeless procedure lead to lower complication rates in PCNL. All of the established procedures have their own range of indication with regard to size and location of the stone. They amplified the possibility of a customized therapy for each patient.

Tubeless mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for lower calyceal stones of ⩽2 cm: A prospective randomised controlled study

Objective

To assess the safety, efficacy, and stone-free rate (SFR) of mini-percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) for the management of lower calyceal stones of ⩽2 cm, and to determine the advantages and disadvantages of each.

Patients and methods

In all, 120 patients with lower calyceal stones of ⩽2 cm were randomly divided into two equal groups: Group A were managed by mini-PCNL and Group B by RIRS using flexible ureteroscopy and laser. The mean age, sex, stone size, operating time, complications, hospital stay, and SFR were compared between the groups. The success of the procedure was defined as the absence of residual stones or small residuals of ⩽0.2 cm on computed tomography at 12 weeks postoperatively.

Results

Both groups were comparable for preoperative parameters. The mean (SD) operating time was statistically significantly longer in Group B [109.66 (20.75) min] as compared to Group A [71.66 (10.36) min]. Although the hospital stay was longer in Group A as compared to Group B this was not statistically significant (P = 0.244). The SFR for Group A was 92.72% and for Group B it was 84.31%, which was not significantly different (P = 0.060).

Conclusion

For treating lower calyceal stones of ⩽2 cm mini-PCNL and RIRS are comparable. Mini-PCNL had a better SFR than RIRS but the hospital stay was longer and there were more intraoperative complications, whilst, RIRS had a significantly longer operating time compared with mini-PCNL and a higher incidence of postoperative fever, and a lower SFR.

Minimally Invasive ("Mini") Percutaneous Nephrolithotomy: Classification, Indications, and Outcomes

Minimally invasive endoscopic procedures are often employed for the surgical removal of kidney stones. Traditionally, large stones are removed by (standard) percutaneous nephrolithotomy (SPCNL). Although effective for the clearance of large stone burdens, SPCNL is associated with significant morbidity. Therefore, in an effort to reduce this morbidity, while preserving efficacy, mini-PCNL (MPCNL) with a smaller tract size (<20 French) was developed. Several studies suggest that MPCNL has a comparable stone-free rate to SPCNL. However, the question of lower morbidity with MPCNL remains unanswered. In this review, we describe the equipment, indications, and efficacy of MPCNL with particular attention to its value over traditional minimally invasive stone removal techniques.

Optimal management of lower pole stones: the direction of future travel

INTRODUCTION

Kidney stone disease is increasing worldwide with its most common location being in the lower pole. A clear strategy for effective management of these stones is essential in the light of ever increasing choice, effectiveness, and complications of different treatment options.

MATERIAL AND METHODS

This review identifies the latest and clinically relevant publications focused on optimal management of lower pole stones.

RESULTS

We present an up-to-date European Association of Urology and American Urological Association algorithm for lower pole stones, risks and benefits of different treatments, and changing landscape with the miniaturization of percutaneous stone treatments.

CONCLUSIONS

Available literature seems to be deficient on quality of life, patient centered decision making, and cost analysis of optimal management with no defined standard of 'stone free rate', all of which are critical in any surgical consultation and outcome analysis.

Clearance rates of residual stone fragments and dusts after endoscopic lithotripsy procedures using a holmium laser: 2-year follow-up results

PURPOSE

To investigate the spontaneous clearance rates of remnant particles following miniaturized percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS).

METHODS

Among 624 patients who underwent mini-PCNL or RIRS at our institution from 2011 to 2015, we collected data of 247 patients with 2 years of follow-up. Of these, we included 148 patients with unilateral renal stones between 10 and 30 mm, as well as remnant particles after surgery. The size criteria of dusts and residual fragments (RFs) were, respectively, <1 and <3 mm.

RESULTS

After excluding 22 patients, 126 patients (RFs = 21, dusts = 98, and both RFs and dusts = 7) were analyzed. Mean age was 56.5 (±14.4) years, and mean stone size was 19.5 (±12.5) mm. The mean follow-up period was 18.5 (± 12.9) months. In patients whose remnant particles were naturally eliminated following lithotripsy, the mean stone passage time was 9.0 (±9.3) months in the dusts and 13.9 (±11.1) months in the RFs groups (P = 0.135). Remnant particles disappeared in 42 out of 105 patients (40.0 %) in dusts and 7 out of 28 patients (25.0 %) in RFs groups (P = 0.187). The size of dusts and RFs increased, respectively, in 18.1 % (19/105) and 28.6 % (8/28) of patients with remnant particles during the follow-up period.

CONCLUSIONS

The presence of dusts and RFs was poor prognostic factors in patients underwent renal stone surgery using a holmium laser. Complete residual stone removal by using a basket or dusts eradication by irrigation for an adequate time during surgery can be a good surgical strategy.

Comparison of minimally invasive percutaneous nephrolithotomy and flexible ureteroscopy for the treatment of intermediate proximal ureteral and renal stones in the elderly

The aim of this study is to compare the outcomes of flexible ureteroscopy (fURS) and minimally invasive percutaneous nephrolithotomy (mPNL) for the treatment of renal and/or proximal ureteral stones sized 1-2 cm in the elderly (≥60 years). Between January 2010 and March 2015, 184 consecutive mPNL and fURS were performed to treat intermediate renal and/or proximal ureteral stones in geriatric patients. The records were retrospectively reviewed and outcomes were compared. Although no significant difference was found in the complication rate between two groups, a statistical trend (p = 0.059) in favor of fURS was observed. In addition, multivariate analysis demonstrated that mPNL, preoperative positive urine culture and lower hemoglobin were independent risk factors for postoperative complication (p = 0.016, p = 0.021, p = 0.001, respectively). And fURS was significantly associated with less hemoglobin drop, red blood cell transfusion, analgesics requirement, postoperative hospital duration, and charges of laboratory tests, medical examinations and medications (p = 0.019, p = 0.037, p = 0.006, p = 0.000 and p = 0.007, p = 0.000, p = 0.000, p = 0.001, respectively), while higher costs of operations (p = 0.008). Receiver operating characteristic curve suggested a preoperative hemoglobin of 106.5 g/L as the threshold for predicting red blood cell transfusion after mPNL. The overall one-session stone-free rate of fURS at 1 month was lower (p = 0.006), while it was similar for solitary stone between two groups. Comorbidity and previous stone surgery did not affect postoperative complication and stone-free rate. This study shows that mPNL is more effective for multiple stones, but fURS is associated with potentially less complications and postoperative hospital stay. Furthermore, preoperative hemoglobin level and urine culture can be used to predict postoperative complication risk and they may be helpful in choosing treatment methods for the elderly.