Comparative study of retrograde intrarenal surgery and micropercutaneous nephrolithotomy in the treatment of intermediate-sized kidney 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.

Percutaneous nephrolithotomy in children

INTRODUCTION

The high success rates of percutaneous nephrolithotomy (PCNL) in the clearance of large renal calculi has made it a primary mode of surgical management in adults. Similarly, in children too PCNL has been gaining ground and the indications for the same are on the rise. We retrospectively evaluated the safety and efficacy of this technique, in children below 18 years of age.

MATERIALS AND METHODS

We retrospectively reviewed the inpatient, outpatient records, imaging films of all children with renal stones undergoing PCNL at our hospital.

RESULTS

During the study period, 123 children underwent 129 PCNL at our centre for renal calculi. The mean age was 11.06 years and 87 (70.73%) of the children were males. The size of the stones varied from 15 to 37 mms in the longest diameter. A complete staghorn was noted in six (4.65%) and a partial staghorn in nine (6.97%) children. Supine PCNL was performed in 21 (16.2%) children and remaining 102 (83.7%) children underwent PCNL in prone position. The mean drop in haemoglobin was 1.24 gm%. Stone clearance was achieved in 122 (94.5%) children. Post-operatively four (3.1%) children needed blood transfusions due to excessive bleeding.

CONCLUSIONS

Refinements in percutaneous access techniques, miniaturization of instruments, and technologic advances in energy sources for lithotripsy have led to improvement of outcomes and have lowered the morbidity rates in children following PCNL. It is a safe and effective means of clearing large volumes of renal calculi with minimal morbidity.

Retrospective analysis of the factors affecting intraoperative and immediate postoperative complications of RIRS classified by the Clavien and Satava grading systems

BACKGROUND

To classify intraoperative and postoperative complications using the modified Clavien classification system(MCCS) and modified Satava classification system(SCS) and to evaluate the parameters associated with complications in patients undergoing retrograde intrarenal surgery(RIRS) for renal and proximal ureteral stones.

MATERIALS AND METHODS

We performed a retrospective analysis of 949 patients who underwent RIRS for renal stones and proximal ureteral stones at two institutions between March 2015 and June 2020. Intraoperative complications were assessed using SCS and postoperative complications were graded according to MCCS. Univariate and multivariate analyses were undertaken to determine predictive factors affecting complication rates.

RESULTS

The median stone size was determined as 13 mm (range 10-20 mm). The stone-free rate was 83.6% after the first intervention. Reprocedure was applied to 89 of the patients with residual stones and the final stone-free rate was 94.4% after reprocedure. According to SCS, the number of intraoperative events and complication incidences was 153(16.1%). MCCS revealed postoperative complications in 121(12.8%) patients. Major complications were observed in 18(1.9%) patients. The rate of complications was higher in patients with renal anomalies (9.9% vs 3.4%, p=0.001). Stone location, stone size, stone burden, stone number, stone density and residual fragments were determined to be associated with the development of complications (p<0.001,p<0.001,p<0.001, p<0.001,p=0.002 and p<0.001 respectively). In addition, the multivariate analysis revealed that only presence of residual fragments was a significant predictor of complication development for the patients with Grade≥3 complications according to MCCS (p=0.032). However, significant predictors were stone burden (p<0.001), stone density (p=0.002) and fluoroscopy time (p<0.001) for those with Grade≥2b complications according to SCS.

CONCLUSION

This study showed that abnormal kidney anatomy, operation time, stone burden and residual fragments were reliable predictors of complication development during and after RIRS. Appropriate preoperative management should be planned according to these predictors to prevent intraoperative and postoperative complications.

Micropercutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of renal stones: A systematic review and meta-analysis

Objective

To compare the efficacy and safety of micropercutaneous nephrolithotomy (Microperc) and retrograde intrarenal surgery (RIRS) in treating renal stones using published literature.

Methods

A systematic literature review was performed on August 21, 2017, using PubMed, Embase, and Cochrane Library databases in accordance with the PRISMA guidelines. Summarized mean differences (MDs) or odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the differences in outcomes between Microperc and RIRS.

Results

A total of nine studies (7 in adult patients and 2 in pediatric patients) containing 842 patients (381 Microperc cases and 461 RIRS cases) with renal stones were included in this analysis. Among the adult patients, Microperc was associated with higher stone-free rate(SFR)(OR: 1.6; 95% CI, 1.03 to 2.48), significantly longer hospital stays (MD: 0.66 day; 95% CI, 0.17 to 1.15), longer fluoroscopy time (MD: 78.12 s; 95% CI, 66.08 to 90.15), and larger decreases in hemoglobin (MD: 0.59 g/dl; 95% CI, 0.16 to 1.02) than was RIRS. No significant differences were observed with respect to operative time, stone-free rate, complication rate or auxiliary procedures.

Conclusions

Our results demonstrated that Microperc might be more effective in adult patients than RIRS will due to its higher SFR. However, longer hospital stays, longer fluoroscopy time and a larger decrease in hemoglobin should be considered cautiously.

Digital Videoscopic Retrograde Intrarenal Surgeries for Renal Stones: Time-to-Maximal Stone Length Ratio Analysis

PURPOSE

To investigate 100 consecutive cases of videoscopic retrograde intrarenal surgery (RIRS) by a single surgeon and to evaluate factors associated with stone-free status and the learning curve thereof.

MATERIALS AND METHODS

We analyzed the results of videoscopic RIRS in 100 patients who underwent primary treatment for renal stones from January 2015 to August 2016. Videoscopic RIRS were performed with URF-V and URF-V2 flexible video uteroscopes (Olympus) or a Flex-Xc flexible ureterorenoscope (KARL STORZ). Non-contrast computed tomography was taken at 3 months postoperatively to confirm the absence of stones. The stone characteristics included the location, maximal stone length (MSL), stone heterogeneity index (SHI), and mean stone density (MSD). Fragmentation efficacy was calculated as operative time (min) divided by removed MSL (mm), and was evaluated in the sequential order of operations.

RESULTS

The mean age of the total patient was 60.0±14.0 years. The mean MSL was 13.1±6.2 mm. The average MSD was 734.2±327.6 Hounsfield unit (HU) and the SHI was 241.0±120.0 HU. The mean operation time was 65.1±45.7 min considering each renal unit. The stone-free rate at 3 months post-surgery was 87%. The estimated cut-off of the time-to-MSL ratio below 5 min/mm was 50. Multivariate analyses indicated a lower MSD [odds ratio (OR): 0.998; 95% confidence interval (CI): 0.996-0.999; p=0.047) and the last 50 cases (OR: 5.408, 95% CI: 1.337-30.426; p=0.030) as independent predictors of stone-free status after videoscopic RIRS.

CONCLUSION

Low MSDs and the last 50 cases were significant predictors of stone-free rate in videoscopic RIRS.

Trends in the management of urolithiasis in Latin America, Spain and Portugal: results of a survey in the Confederación Americana de Urología (CAU)

OBJECTIVE

To describe the trends in the current management of urolithiasis in the Confederación Americana de Urología (CAU) setting to recognise patterns of clinical practice and identify educational needs.

MATERIAL AND METHOD

An online survey was created with 31 multiple-choice questions (Spanish and Portuguese) through www.caunet.org, which revealed demographic data, patterns of clinical practice and approaches for specific clinical conditions.

RESULTS

A total of 463 practitioners from Brazil, Mexico, Argentina, Spain, Colombia, Chile and other countries (3.96% of the members of CAU) completed the survey. All participants performed some type of urolithiasis treatment: 98.5% performed semirigid ureteroscopy (URS), 83.8% performed percutaneous nephrolithotomy (PCNL), 78.2% performed flexible URS, and 67.2% performed extracorporeal lithotripsy. The youngest physicians tended to perform PCNL (P<.001), and the proportion of users of flexible URS was greater in the Portuguese countries (P=.037). The main energy source was laser (60.7%). Small-calibre PCNL was performed by 15.3% of the respondents, more often in university hospitals (P<.01) and by older practitioners (P<.01). Only 3.2% of the respondents used percutaneous access to the kidney guided exclusively by ultrasound, especially the older practitioners (P<.001). The supine position was used by 40.4% of the respondents, more often in Spain (P<.001) and in the university setting (P=.017). PCNL without nephrostomy was practiced by 3.9% of the respondents. For flexible URS, 19.2% of the respondents did not use ureteral access sheaths, and the older practitioners preferred thinner calibre sheaths (P<.001).

CONCLUSIONS

The management of lithiasis in the CAU setting follows a profile similar to that recognised in the European and American clinical guidelines, although there are interesting variations based on the practitioner's age and preferences. We identified potential areas for improvement in small-calibre PCNL and ultrasound-guided puncture.

"Microperc" micropercutaneous nephrolithotomy: a review of the literature

Recent years have seen innovations in working armamentarium of percutaneous nephrolithotomy (PCNL) leading to development of novel modifications such as miniperc, ultra miniperc, and microperc. Amongst these microperc appears to be least invasive and various authors, off late, have reported their experience with the technique. Literature on microperc was reviewed by a MEDLINE/PubMed search with articles in the English language since 2011 in published peer-reviewed journals. Articles comprised of case series, comparative, and noncomparative studies. Different facets encompassing the technique were analyzed including contemporary indications, technique and its modifications, outcomes, and comparison with other modalities. Technique is reported to be associated with high success rate (82-100%) and short hospital stay (1-2 days). Studies have reported minimal hemoglobin drop (0.1-1.4 gm%) and fewer complications of lower Clavien grades. Going small in PCNL has gone a long way to present day 4.85F puncture system. Utilization of this novel modification is on rise with larger case series and comparative analysis being reported in past 2 years. Technique boasts of high clearance rate, lower morbidity and short hospital stay. In the present era, this innovation in percutaneous stone management appears to be another milestone in quest for "knife to cannula to needle to nothing".

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.

Retrograde intrarenal surgery and micro-percutaneous nephrolithotomy for renal lithiasis smaller than 2 CM

INTRODUCTION

Microperc is the upgraded form of percutaneous nephrolithotomy miniaturization. The aim of this study is to compare prospectively microperc and retrograde intrarenal surgery for the treatment of renal stones smaller than 2 cm.

MATERIAL AND METHODS

A comparative prospective study of both techniques was carried out between January 2014 and June 2015. Thirty-five patients were divided in two groups: Group A, 17 patients treated by retrograde intrarenal surgery and Group B, 18 patients treated by microperc. Stone clearance was assessed using CT scan 3 months after surgery.

RESULTS

Both groups were statistically comparable as demographic variables and stone size was similar (16.76 mm Group A vs 15.72 mm Group B). Success rate, hospital stay and JJ stenting were similar for both groups. There was no statistically significant difference regarding post-operatory complications: 17.64% Group A vs 5.56% Group B (p=0,062), all of them Clavien I and II. Surgical time was statistically different (63.82 min Group A vs 103.24 min Group B) as well as hemoglobin drop (0.62 g/dl Group A and 1.89 g/dl Group B).

CONCLUSION

Microperc is an effective and safe procedure for the treatment of renal lithiasis smaller than 2 cm, which makes it a good alternative to retrograde intrarenal surgery for this stone size. However, more prospective studies that include a larger cohort are necessary to confirm our results.

Complications of retrograde intrarenal surgery classified by the modified Clavien grading system

The increase in the retrograde intrarenal surgery (RIRS) has been accompanied by the increase in complications. This study identified the factors that affected the severity of the complications using the modified Clavien classification system (MCCS). Three hundred and twenty-two consecutive RIRS performed by a single surgeon were analyzed. Data collection included demographics, clinical parameters, and perioperative and postoperative complications. The rate of adverse events for each of the Clavien grades was calculated, and statistical comparisons were made. The impact of each of the factors on the severity of the complications, based on the MCCS, was investigated using the univariate and multivariate analyses. The total complication rate was 26.1% (MCCS: I = 67.7%, II = 22.7%, IIIb = 7.2%, IVb = 2.4%). On the univariate analyses, the following factors affected complication: positive preoperative urine culture, operative time, irrigation rate, and stone burden. Multivariate logistic regression analysis demonstrated that positive preoperative urine culture, irrigation rate, and operative time were the significant factors affecting the complications. Most of the RIRS complications were in the lower Clavien grades and major complications were uncommon. Positive preoperative urine culture, irrigation rate, and operative time were the factors that affected complications.

Therapeutic possibilities for urolithiasis in childhood

OBJECTIVES

We present our case studies on paediatric urolithiasis, the techniques employed in its treatment and its results.

MATERIAL AND METHODS

A retrospective study of paediatric urolithiasis of the upper urinary tract (UUT) treated at our centre between 2003 and 2014. We recorded demographic, clinical, diagnostic and therapeutic data and the complications. The therapeutic plan was recorded as isolated (extracorporeal lithotripsy, ureterorenoscopy, nephrolithotomy or surgery) or combined therapy.

RESULTS

We examined 41 renal/urethral units in 32 patients. The median age was 5 years (range, 11 months-14 years). The mean size was 12.9cm (±7.3mm). The locations were as follows: 23 (56%) in the renal pelvis (staghorn in 15 cases), 10 (24) in lower calyx and 8 (20%) in the urethra. We performed 80 procedures, with no differences in the age groups, which resulted in 12 complications (15%) but no septic condition secondary to lithotripsy. Stone removal from the urethra had a 100% success rate with the ureterorenoscopy. The overall cure rate was 90%.

CONCLUSION

The paediatric urolithiasis approach offers multiple alternatives. It is therefore important to tailor the procedure according to the size, location and composition of the stone. In our centre, the use of paediatric extracorporeal shock wave lithotripsy is safer. Ureterorenoscopy, semirigid or flexible, provides excellent results in ureters. Percutaneous nephrolithotomy with minimal access can be performed on small children and nursing infants.