Renal parenchymal injury after standard and mini percutaneous nephrostolithotomy

Urolithiasis in Kidney Transplant Patients: A Multicenter KSER Research Series

Background and Objectives: Urolithiasis occurrence is uncommon in kidney transplantation patients, though it has serious implications, including acute kidney injury in the transplanted kidney. This study investigates the leading causes of urolithiasis in kidney transplantation patients, the diagnostic process, and the outcomes of multimodal management. Materials and Methods: Data collection spanned from January 1997 to December 2021, involving kidney transplantation patients with urolithiasis from the database of the Korean Society of Endourology and Robotics (KSER) research committee. Analysis encompassed factors triggering urolithiasis, the diagnostic process, stone attributes, treatment methods, and outcomes. Results: Our analysis included 58 kidney transplantation patients with urolithiasis from eight medical centers. Of these patients, 37 were male and 4 had previous urolithiasis diagnoses. The mean age was 59.09 ± 10.70 years, with a mean duration from kidney transplantation to diagnosis of 76.26 ± 183.14 months. The most frequent method of stone detection was through asymptomatic routine check-ups (54.7%). Among the 58 patients, 51 underwent stone treatment. Notably, 95.3% of patients with ureter stones received treatment, a significantly higher rate than the 66.7% of patients with renal stones (p = 0.010). Success rates showed no significant differences between renal (70%) and ureter stone (78.0%) groups (p = 0.881). Conclusions: Urolithiasis in transplanted kidneys constitutes an acute condition requiring emergency intervention. Endo-urological interventions are effective for kidney transplantation patients with urolithiasis. To ensure prevention and early detection, diligent follow-up and routine imaging tests are necessary.

Mini-versus standard percutaneous nephrolithotomy in pediatric population: A randomized controlled trial

INTRODUCTION

Mini PCNL has gained popularity in adult patients due to reduction in the complication rate with comparable stone free rate. There is paucity of level 1 evidence regarding the benefit of mini PCNL in the pediatric group.

OBJECTIVE

We performed a randomised study to compare mini PCNL (mPCNL) with standard PCNL (sPCNL) for the management of renal calculi in patients less than 18 years of age in terms of safety, efficacy, and stone-free rate (SFR).

MATERIALS AND METHODS

A randomised controlled trial was performed on 50 children who underwent PCNL from June 2015 to March 2021, who were divided into two groups. Group I had 25 patients managed with mPCNL (sheath size 16.5 Fr) and Group II had 25 patients who underwent sPCNL (sheath size 26 Fr). Primary outcomes including stone free rates (SFR) and hemoglobin drop and secondary outcomes like operative time, complications, pain score, need of analgesia, incidence of nephrostomy site leak, hospital stay in days were compared between the two groups.

RESULTS

The mean age of patients in groups I and II was 9.4 ± 2.6 and 10.4 ± 2.26 years, respectively (p = 0.15). The mean stone sizes in both groups I and II were 18.6 ± 2.56 and 20.2 ± 3.58 mm, respectively (p > 0.05). The stone free rate for group I was 88% and for group II, 92% (p = 0.64). The average drop in hemoglobin was higher in group II compared to group I (1.1 ± 0.31 g/dl and 1.7 ± 0.23 g/dl respectively; p < 0.0001), however the mean blood transfusion rate was not significantly different in both groups. The operating time was shorter in group II compared to group I (p-value - 0.0030). The pain scores were lesser for the group I. Grade I complications were higher in group II as compared to group I (p-0.047); however, grade II complications were comparable in both groups. The mean hospital stay was not significantly different in both groups.

DISCUSSION

This study confirms the role of mini PCNL in pediatric patients with renal stones. The stone clearance rate of mini PCNL is equivalent to standard PCNL, with lesser blood loss and postoperative complications, however with longer operative time during mPCNL. The small number of the participants in both arms is a limitation of this study and may also reflect fewer children with urolithiasis being treated surgically even in a tertiary care referral centre.

CONCLUSIONS

Mini-PCNL offers equivalent stone free outcome with lower complications rate compared to the standard PCNL for all types of renal stones.

Comparison of renal parenchymal trauma after standard, mini and ultra-mini percutaneous tract dilation in porcine models

OBJECTIVE

To evaluate whether reducing tract dilation diameter in PCNL (percutaneous nephrolithotomy) procedures results in minimizing of renal trauma of the percutaneous tract.

METHODS

A percutaneous renal access tract was established bilaterally to 11 pigs. Two pigs were euthanized immediately after the experiment, while nine pigs were sacrificed 1 month later. The percutaneous accesses were dilated up to 30Fr, 22Fr or 12Fr. The animals underwent a contrast-enhanced computer tomography immediately after the procedure and 30 days later. DMSA-scintigraphy with SPECT-CT was also performed. The kidneys of all animals were harvested for histological evaluation. The volume of scar tissue and the percentage of renal volume replaced by scar tissue were calculated.

RESULTS

Immediate post-procedural CT-scans revealed a significant difference in defect diameter among the three modalities. However, the scar volume calculated on CT-images and histopathology showed a significant difference only when 30Fr dilation was compared to 12Fr dilation. The percentage of scar volume was negligible in all cases, but there was still a statistical difference between 30 and 12Fr dilation. Dilation up to 22Fr revealed no statistical differences compared to the other two modalities. DMSA-scintigraphy showed no scar tissue in any case.

CONCLUSION

Dilation up to 30Fr may cause a significantly larger scar tissue on renal parenchyma compared to 12Fr dilation as it was shown on CT-images and microscopic evaluation, but based on the DMSA/SPECT-CT this difference seems to be insignificant to the renal function. The scar tissue caused by 22Fr dilation seemed to have no significant difference from the other modalities.

Totally tubeless single access tract mini-percutaneous nephrolithotripsy in treatment of large burden > 2-cm and/or complex renal stones: a case series of 62 patients

Background

Limited literature has focused on the use of totally tubeless mini-percutaneous nephrolithotomy (PCNL) for the treatment of large renal stones. We present our findings of treating patients with large and/or complex renal stones using single renal access totally tubeless mini-PCNL.

Methods

From March 2018 to May 2021, 62 consecutive cases in which single tract totally tubeless mini-PCNL was used to treat complex renal stones were enrolled, all with calculi > 2 cm. All procedure of puncture and dilation were guided by fluoroscope. The complexity of stones was assessed according to the Guy’s Scoring System (GSS). The surgical duration, length of hospital stay, analgesia requirement, stone-free rate, and perioperative morbidity were assessed.

Results

The mean preoperative stone burden was 36.69 ± 19.76 mm (above 2 cm in all cases), mean surgical duration was 61.93 ± 40.84 min (range 15–180 min), and mean hematocrit reduction was 4.67 ± 2.83%. Postoperative Nalbuphine was used in 6 patients. The mean length of stay was 2.46 ± 1.19 days (range 2–8 days), and the postoperative stone-free rate was 83.9% (52/62), and 87.1% (54/62) after auxiliary ESWL. The overall complication rate was 14.5%, the majority of complications being postoperative transient fever.

Conclusion

For the treatment of large bursen > 2 cm and/or complex renal stones, totally tubeless single tract mini-PCNL ensures a feasible SFR, low morbidity and short hospital stay. According to the low complication rate in our study, the totally tubeless manner was not associated with an increased risk of postoperative morbidity, and patients benefited from decreased postoperative analgesics use.

Pediatric Stone Surgery: What Is Hot and What Is Not

PURPOSE OF REVIEW

We aim to highlight recent advances in technology and techniques for surgical management of urinary tract calculi in pediatric patients.

RECENT FINDINGS

Percutaneous nephrolithotomy (PCNL) is classically performed in the prone position. The supine PCNL was first attempted to overcome the shortcomings of difficult airway access, patient and surgeon discomfort. The supine PCNL, and subsequent modifications, has been successfully described in the pediatric population. Classically, PCNL has also been classically concluded with obligate placement of a nephrostomy tube and bladder catheter. Recently, tubeless and totally tubeless PCNL reduces pain and duration of hospitalization with satisfactory surgical outcomes in children. Finally, we describe the use of thulium laser technology, which offers improved efficacy in stone treatment and may supplant the current dominant technologies in coming years. Recent advances in pediatric stone surgery include supine PCNL, miniaturized PCNL instrumentation, tubeless procedures, and thulium laser technology.

Feasibility of one-shot dilation access in the pediatric age group

Objective

To compare sequential fascial dilation (SFD) versus one-shot dilation (OSD) in the pediatric patients undergoing percutaneous nephrolithotomy.

Methods

The present study is an observational study. The study subjects were divided into two groups. In group 1, renal dilation was done using the SFD and in group 2, renal dilation was done using the OSD. The amount of time exposed to radiation during access to pelvicalyceal system was estimated. Complications, stone free rates, ancillary procedures for residual stones and hospital stay were compared. Modified Clavien-Dindo classification was used for grading the complications.

Results

Radiation exposure and operative time were less in OSD group (95% confidence interval (CI) 3.068 to 14.072, and 2.565 to 12.435, p<0.005). The mean drop of hematocrit was statistically less significant in OSD group (p=0.032). In both groups, complications, stone free rate and hospital stay were statistically insignificant.

Conclusions

OSD is feasible in the children with reduced radiation exposure and shorter operative time. The outcome was similar to SFD.

Ultra-mini-percutaneous nephrolithotomy in flank-free modified supine position versus prone position in treatment of pediatric renal pelvic and lower calyceal stones

OBJECTIVES

To report the safety and efficacy of ultra-mini-percutaneous nephrolithotomy (UMPCNL) in flank free modified supine (FFMS) and prone positions in management of pediatric renal calculi.

PATIENTS & METHODS

This prospective randomized study included 55 pediatric patients with symptomatic renal stones and suitable for ultra-mini-percutaneous nephrolithotomy. They were randomized into two groups. Group A included 28 patients who were treated by UMPCNL in FFMS position (with a pad below the ipsilateral shoulder and buttocks, putting ipsilateral upper limb over the chest, and crossing the extended ipsilateral lower limb over the flexed contralateral one) and Group B included 27 patients treated by UMPCNL in the prone position. In both groups dilatation was done to 13 French sheath allowing the introduction of 6/7.5 French semi-rigid ureteroscope and fragmentation of stones by Ho:YAG laser with a 550-μm fiber laser lithotripter.

RESULTS

The operation time in FFMS position UMPCNL group was significantly shorter than prone position UMPCNL group (84.3±9.87 vs. 99.3±8.75) minutes with p=0.022. There was no significant difference between both groups in terms of stone free rate (89.3% vs. 88.9%), overall complication rate (including transient fever) (21.4% vs. 18.5%), post-operative pain (VAS score) (3.4±0.8 vs. 3.3±0.9), or hospital stay (3.53±0.8 vs. 4.1±1.1) days.

CONCLUSION

Both ultra-mini-percutaneous nephrolithotomy in FFMs and prone positions are feasible, safe and effective in treatment of pediatric renal stones with relatively shorter operative time in FFMS position.

Mean Changes in Estimated Glomerular Filtration Rate in Patients Undergoing Percutaneous Nephrolithotomy Having Renal Stone Disease

Background

Urinary stone disease is associated with renal impairment because of obstruction and infection. Comorbidities include hypertension, dyslipidemia, diabetes, and impaired renal function. Furthermore, as recurrences are common in urolithiasis, such patients undergo many treatments throughout their life. Percutaneous nephrolithotomy (PCNL) is an effective treatment for renal stones with a diameter greater than 2 cm. The primary objective of this study was to observe the mean changes in estimated glomerular filtration rate (GFR) in patients undergoing PCNL having renal stone disease.

Methodology

This cross-sectional study was conducted for six months between June and November 2020 at a tertiary care hospital in Karachi, Pakistan. All male and female patients aged between 15 and 70 years who were diagnosed with renal stones using X-ray of the kidney, ureter, and bladder or using ultrasound of the abdomen and planned for PCNL were selected. Patients with any duration of kidney stone disease were included. Statistical Package for Social Sciences version 20.0 (IBM Corp., Armonk, NY, USA) was used to statistically analyze the data.

Results

The mean age of the patients was 41.11 ± 14.30 (17-70) years. A total of 61 (38.1%) patients were female and 99 (61.9%) were male. Mean preoperative GFR was 91.22 ± 5.88 mL/min which decreased to 83.64 ± 5.70 mL/min at 48 hours post-PCNL. GFR significantly decreased after surgery (p = 0.0001).

Conclusions

During early postoperative days, GFR was decreased in patients undergoing PCNL. Factors that may impair renal function should be avoided during the first few days after undergoing PCNL. Further large-scale studies are needed to investigate these changes in GFR in post-PCNL patients.

Which factors affect the success of pediatric PCNL? Single center experience over 20 years

OBJECTIVE

We aimed to investigate the impact of surgeons' experience on pediatric percutaneous nephrolithotomy (PCNL) outcomes.

MATERIALS AND METHODS

Between June 1997 and June 2018, 573 pediatric patients with 654 renal units underwent PCNL for renal stone disease by senior surgeons. Data were divided into two groups, group-1 (n = 267), first ten years period, group-2 (n = 387); second ten years period.

RESULTS

Mean ± SD age of patients was 7.6 ± 4.9 (1-17) years. The stone-free rates (SFR) assessed after 4 weeks were 74.9% vs. 83.4% in group-1 vs. group-2, respectively (p = 0.03). The mean operation time, fluoroscopy time, and the number of patients requiring blood transfusion significantly decreased in group 2 (100.4 ± 57.5 vs. 63.63 ± 36.3, 12.1 ± 8.3 vs. 8.3 ± 5.4, and 24.3% vs. 2.9%; p < 0.001, p < 0.001, and p = 0.002 in group-1 versus group-2, respectively). On multivariate analysis, increasing stone size increased operation time (p < 0.001), fluoroscopy time (p < 0.001), intraoperative and postoperative blood transfusion rates (p = 0.006 and p = 0.018, respectively), and hospital stay (p = 0.002) but was not associated with change of glomerular filtration rate (GFR) (p = 0.71). Sheath size also correlated with increased fluoroscopy time (p < 0.001), operation time (p < 0.001), intraoperative blood transfusion (p < 0.001) and hospital stay, but sheath size did not affect postoperative blood transfusion (p = 0.614) or GFR change (p = 0.994).

CONCLUSIONS

The percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure and is well accepted because of its lower complication rate and high efficiency for pediatric patients. Stone and sheath size are predictive factors for blood loss and hospital stay. During 20 years, our fluoroscopy time, operation time, blood loss, and complication rates decreased, and stone-free rate increased.

Tract sizes in percutaneous nephrolithotomy: does miniaturization improve outcome?

PURPOSE OF REVIEW

To provide a summary of surgical outcomes in percutaneous nephrolithotomy (PCNL) according to various techniques and tract sizes.

RECENT FINDINGS

Recent literature in this field concluded that standard PCNL (sPCNL) remains the optimal treatment for stones between 1 and 2.5 cm and can be managed with tracts 14-20 F, whereas small stones less than 1.5 cm can be treated with tracts under 14 F. According to new datasets, smaller tracts can be equally effective in the treatment and might offer the possibility to reduce bleeding, length of hospital stay, postoperative pain as well as overall complication rates when compared with sPCNL. On the other hand, longer operative time as well as lower stone-free rates, which have been the main drawbacks of the miniaturized approach, have recently shown to be comparable with sPCNL.

SUMMARY

At present, tract size is a highly debatable topic in percutaneous stone therapy. New systems for miniaturized PCNL have been developed to achieve comparable stone-free rates while reducing the incidence of common complications. The adoption of these techniques demands skilled surgeons and institutional investment for the acquisition of new equipment.

Contemporary role of multi-tract percutaneous nephrolithotomy in the treatment of complex renal calculi

Complex renal calculi remain to be a challenge for the treating urologist due to sheer bulk and the technicalities involved. Percutaneous nephrolithotomy (PCNL) remains the treatment modality of choice in dealing with these large and complex stones. The limiting factor in their treatment continues to be the need for using additional tracts or the use of flexible nephroscopy for complete stone clearance. This systematic review focuses on the need for multi-tract PCNL for complex renal calculi. The literature review was performed using PubMed database using the keywords "multiple tract PCNL" or "multiperc". We identified original articles published on the usage of multiple tracts for stone clearance in renal calculi between January 2000 to October 2018, and the search was restricted to available literature in English language only. Ten studies with n>20 were included for the final analysis. We analyzed the technical efficacy with respect to the number of tracts and stages that were required for stone clearance, outcomes and complications, especially, procedural bleeding and post-procedure infective complications of multiple-tract PCNL for large burden renal stones. Multiperc is found to be safe, feasible and effective for the management of large burden complex renal calculi with respect to stone clearance and morbidity associated with the procedure. It is cost effective and complete stone clearance as a single procedure is higher in comparison to flexible ureteroscopy and shockwave lithotripsy.

Mini- versus standard percutaneous nephrolithotomy for treatment of pediatric renal stones: is smaller enough?

INTRODUCTION

Miniaturized percutaneous nephrolithotomy (PCNL) has gained increased popularity owing to efforts in recent years to lower peri-operative morbidity while maintaining a high stone-free rate (SFR).

OBJECTIVE

The outcomes of pediatric renal stones treated by mini-PCNL (MPCNL) versus standard PCNL (SPCNL) were retrospectively assessed.

STUDY DESIGN

A retrospective data analysis of 134 consecutive patients younger than 17 years who underwent PCNL between January 2014 and July 2018 was performed. The patients were categorized into two treatment groups depending on the tract size and instruments used. Seventy-five patients were treated by SPCNL using adult instruments via a 22-26 Fr tract, and 59 patients were treated by MPCNL using pediatric instruments via a 16-20 Fr tract.

RESULTS

A total of 134 children (SPCNL = 75; MPCNL = 59) underwent PCNL and subsequent evaluation. Patient demographics and stone characteristics were comparable between the two groups. The mean stone size ranged from 1.9 ± 1.162 cm in the MPCNL group to 2.2 ± 1.424 cm in the SPCNL group, and the overall SFR was 89.5% in the MPCNL group and 94.7% in the SPCNL group. When comparing the common characteristics, no significant difference was found between the two surgical access regarding the mean operative duration, SFR, incidence of peri-operative complications, and the rate of bleeding requiring a blood transfusion. Conversely, the mean postoperative hemoglobin decrease was significantly lower in the MPCNL group relative to the SPCNL group, at 0.354 ± 0.299 g versus 0.568 ± 0.332 g, respectively (P = 0.001). In addition, the mean duration of hospitalization was significantly lower in the MPCNL group than in the SPCNL group, at 1.91 ± 1.154 days compared with 2.41 ± 1.14 days, respectively (P = 0.014).

DISCUSSION

Herein, the authors report the first systematic review of the first center in the locality treating this cross section of patients. This review reveals that the use of these smaller instruments can deliver a strong safety profile while achieving good stone clearance. As an alternative to decreasing the peri-operative morbidity associated with SPCNL, MPCNL can be conveniently used without affecting the outcomes of the procedure. It is a safe and feasible procedure for maximal clearance of stones and should comprise the treatment of choice-regardless of age-for experienced endourologists.

CONCLUSION

MPCNL represents a valuable way of treating simple and complex renal stones in children, with an operative time, SFR, and overall complication rate comparable with those of SPCNL. Mini-PCNL resulted in shorter hospitalization and fewer hemoglobin drops.

Mini Versus Standard Percutaneous Nephrolithotomy: The Impact of Sheath Size on Intrarenal Pelvic Pressure and Infectious Complications in a Porcine Model

OBJECTIVE

To determine how sheath and endoscope size affect intrarenal pelvic pressures and risk of postoperative infectious complications comparing "Mini" vs "Standard" percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

Uropathogenic Escherichia coli were grown and 10⁹ of them were instilled into the porcine renal pelvis through retrograde access for 1 hour. Percutaneous access utilized a 14/16F 20 cm ureteral access sheath for the Mini arm and a 30F sheath for the Standard arm. Nephroscopy was simulated utilizing either an 8/9.8F semirigid ureteroscope or 26F nephroscope for 1 hour while intrarenal pelvic pressure was continuously monitored. Blood and tissue cultures of kidney, liver, and spleen biopsies were plated and incubated and positive cultures were confirmed with polymerase chain reaction.

RESULTS

Intrapelvic pressures were higher in the Mini group, 18.76 ± 5.82 mm Hg vs 13.56 ± 5.82 mm Hg (p < 0.0001). Time spent above 30 mm Hg was greater in the Mini arm, 117.0 seconds vs 66.1 seconds (p = 0.0452). All pigs had positive kidney tissue cultures whereas spleen cultures were positive in 100% and 60% of pigs in the Mini and Standard arms, respectively (p = 0.0253); 90% and 30% had positive liver tissue culture in the Mini and Standard arms, respectively (p = 0.0062). Blood cultures were positive in 30% of pigs in the Mini arm compared with none in the Standard arm (p = 0.0603).

CONCLUSION

Mini-PCNL was associated with higher intrarenal pressures and higher risk of end organ bacterial seeding in the setting of an infected collecting system. This suggests a higher potential for infectious complications in a clinical setting.

Characterization of Flow-Caused Intrarenal Pressure Conditions During Percutaneous Nephrolithotomy In Vitro

PURPOSE

To investigate renal pelvic pressures during percutaneous nephrolithotomy (PCNL) in the standard, mini, and ultramini PCNL systems.

METHODS

We studied an ultramini PCNL system (UMP, outer shaft diameter 13F), a mini PCNL system (MPCNL, shaft 18F, nephroscope 12F), and a standard PCNL system (SPCNL, shaft 27F, nephroscope 24F). Pressure profiles were first investigated in an open model setup, subsequently in a closed model, and finally in an ex vivo porcine kidney. Measurements were determined with the nephroscope in an advanced and pulled-back position for all models.

RESULTS

In the advanced position, maximum pressures of 41.61 ± 0.20 mmHg (UMP), 15.61 ± 0.15 mmHg (MPCNL), and 15.46 ± 0.14 mmHg (SPCNL) were measured in the closed model. In the pulled-back position, maximum pressures were 16.04 ± 0.22 mmHg (UMP), 17.02 ± 0.11 mmHg (MPCNL), and 20.50 ± 0.11 mmHg (SPCNL). In the ex vivo porcine kidney model, maximum pressures were 13.81 ± 6.04 mmHg (UMP), 5.64 ± 0.21 (MPCNL), and 9.21 ± 0.52 (SPCNL) with the nephroscope pushed to end position. After retracting the nephroscope from the outer shaft, pressures in all systems did not exceed 10 mmHg.

CONCLUSIONS

The maximum pressures achieved with the three PCNL systems in all three models were kept below the 30 mmHg critical threshold value. High pressures were only determined for the UMP system with the nephroscope pushed to its end position. This was attributed to the conical shape of the nephroscope, which occupies the space between the nephroscope and outer shaft, resulting in outflow obstruction.

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.

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.

Tract Sizes in Miniaturized Percutaneous Nephrolithotomy: A Systematic Review from the European Association of Urology Urolithiasis Guidelines Panel

CONTEXT

Miniaturized instruments for percutaneous nephrolithotomy (PNL), utilizing tracts sized ≤22 Fr, have been developed in an effort to reduce the morbidity and increase the efficiency of stone removal compared with standard PNL (>22 Fr).

OBJECTIVE

We systematically reviewed all available evidence on the efficacy and safety of miniaturized PNL for removing renal calculi.

EVIDENCE ACQUISITION

The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Since it was not possible to perform a meta-analysis, the data were summarized in a narrative synthesis.

EVIDENCE SYNTHESIS

After screening 2945 abstracts, 18 studies were included (two randomized controlled trials [RCTs], six nonrandomized comparative studies, and 10 case series). Thirteen studies were full-text articles and five were only available as congress abstracts. The size of tracts used in miniaturized procedures ranged from 22 Fr to 4.8 Fr. The largest mean stone size treated using small instruments was 980mm². Stone-free rates were comparable in miniaturized and standard PNL procedures. Procedures performed with small instruments tended to be associated with significantly lower blood loss, while the procedure duration tended to be significantly longer. Other complications were not notably different between PNL types. Study designs and populations were heterogeneous. Study limitations included selection and outcome reporting bias, as well as a lack of information on relevant confounding factors.

CONCLUSIONS

The studies suggest that miniaturized PNL is at least as efficacious and safe as standard PNL for the removal of renal calculi. However, the quality of the evidence was poor, drawn mainly from small studies, the majority of which were single-arm case series, and only two of which were RCTs. Furthermore, the tract sizes used and types of stones treated were heterogeneous. Hence, the risks of bias and confounding were high, highlighting the need for more reliable data from RCTs.

PATIENT SUMMARY

Removing kidney stones via percutaneous nephrolithotomy (PNL) using smaller sized instruments (mini-PNL) appears to be as effective and safe as using larger (traditional) instruments, but more clinical research is needed.

Comparison of Effect of Minimally Invasive Percutaneous Nephrolithotomy on Split Renal Function: Single Tract vs Multiple Tracts

OBJECTIVES

To observe serum creatinine (SCr) and treated side glomerular filtration rate (TGFR) variations in patients with upper urinary tract calculi after minimally invasive percutaneous nephrolithotomy (MPCNL).

PATIENTS AND METHODS

A total of 178 patients underwent MPCNL in our institute and they were retrospectively evaluated between May 2014 and February 2016. SCr and TGFR variations were observed with renal scintigraphy using 99mTc-diethylene triamine pentaacetic acid (^99mTc-DTPA) preoperatively and after at least 6 months of follow-up (FU). The patients were categorized into two groups according to the number of percutaneous access tracts: group I (single tract, n = 122) and group II (multiple tracts, n = 56).

RESULTS

At a mean FU of 7.6 months, SCr dropped from 192.9 ± 151.9/L to 167.6 ± 113.9 μM (13.15% decrease, p = 0.008) and TGFR increased from 29.8 ± 21.2 mL/minute preoperatively to 32.7 ± 22.5 mL/minute postoperatively (9.79% increase, p = 0.022) in group I. Similarly, SCr dropped from 238.5 ± 130.1 to 215.8 ± 128.1μ (9.50% decrease, p = 0.013) and TGFR increased from 29.6 ± 21.4 mL/minute preoperatively to 32.9 ± 25.1 mL/minute postoperatively (11.17% increase, p = 0.014) in group II. No statistically significant difference between two groups according to SCr or TGFR variation was observed (p > 0.05).

CONCLUSIONS

Stone clearance resulted in improvement of split kidney function after single tract or multiple tract MPCNL. Single tract or multiple tract MPCNL did not show statistically significant difference in split renal function postoperative recovery.

Percutaneous nephrolithotomy in children with pediatric and adult-sized instruments

OBJECTIVE

Pediatric stone disease is a significant health issue which has increased in incidence because of lifestyle changes, dietary habits, and obesity. The incidence of urolithiasis among pediatric age groups varies according to region and is high in Turkey. The management of stone disease in children has improved dramatically over the last two decades. The high success rate of percutaneous nephrolithotomy (PNL) have led modern researchers to suggest that it be used as a first-line treatment of kidney stones greater than 2 cm in size. This study compared the outcomes, including morbidity and success rates, of different groups of pediatric patients who underwent PNL via pediatric- and adult-sized instruments.

METHODS

Percutaneous nephrolithotomy was performed in 194 children in a clinical setting between the years 2000 and 2015. Patients were categorized into 2 groups (group 1: pediatric-sized devices used, n = 90 [46.4%]; group 2: adult-sized devices used, n = 104 [53.6%]). The children in group 2 were further divided into subgroups: a 24 F nephroscope was used for group 2a (n = 84 [43.3%]) and a 26 F nephroscope was used for group 2b (n = 20 [10.3%]) (Figure).

RESULTS

For this study, a total of 194 pediatric patients (99 boys and 95 girls ranging from 8 months to 17 years of age, with a mean age of 9.43 years) underwent PNL for the removal of kidney stones in a clinical setting. Between the examined groups, there were no significant differences in patient height or weight, stone site or localization, pre- and post-operative creatinine levels, duration of nephrostomy, or hospitalization time. There was also no significant variation in minor complications such as fever or urinary infection. However, the stone burden was notably smaller in the group wherein pediatric-sized nephroscopes were used. Additionally, the incidence of hemorrhage was markedly lower in groups where a 17 F nephroscope was used than in groups where treatment was administered via 24 and 26 F nephroscopes.

CONCLUSIONS

Stone disease is considered to be relatively rare in childhood, but recent studies have indicated that it presents a considerable health problem. According to some researchers, a decrease in instrument size has not meaningfully reduced complication rates. In contrast, some studies have reported that the use of smaller sized nephroscopes may reduce rates of morbidity and mortality. In this study, success rates of PNL were similar across all groups, regardless of nephroscope size. However, the use of a 17 F nephroscope significantly decreased the rate of hematocrit level reduction (p < 0.001). While instrument size does not affect the success of PNL, smaller instruments can be used to reduce various complications such as bleeding.

Minimally invasive versus conventional large-bore percutaneous nephrolithotomy in the treatment of large-sized renal calculi: Surgeon's preference?

OBJECTIVE

The aim of this study was to compare the efficacy and safety of minimally invasive percutaneous nephrolithotomy (MIP) and conventional percutaneous nephrolithotomy (PCNL) in the treatment of patients with large renal stone burden. MIP has proven its efficacy and safety in the management of small renal calculi. However, conventional PCNL is still considered the standard method for treatment of large renal stones in the upper urinary tract.

MATERIALS AND METHODS

A search of two longitudinal databases in two tertiary referral centres for complex stone disease identified 133 consecutive patients who were treated by either MIP or PCNL for renal stones 20 mm or larger between January 2009 and August 2012. Clinical data and outcome measures of the two methods were compared by Student's t test, chi-squared test or Fisher's exact test. A p value less than 0.05 was considered statistically significant.

RESULTS

Operative time was significantly shorter and hospital stay was significantly longer in conventional PCNL compared to MIP (p = 0.002 and < 0.001, respectively). There were no significant differences in primary stone-free rate or complication rate between the two methods. Only higher graded complications (above Clavien grade II) were significantly more common in conventional PCNL (p = 0.02).

CONCLUSION

MIP is equally effective as conventional PCNL in the treatment of large renal calculi. Both methods have a similar complication rate. The shorter operative time in PCNL may be based on the larger diameter and quicker retrieval of large fragments; the longer mean hospital stay may be caused by the handling of the nephrostomy tube. The current data suggest that the choice of the method mainly depends on the surgeon's preference.

Mini-percutaneous Nephrolithotomy Under Total Ultrasonography in Patients Aged Less Than 3 Years: A Single-center Initial Experience from China

Background:

Urolithiasis in pediatric population is a serious problem with the incidence increased these years. In the management of larger stones (diameters >2 cm), percutaneous nephrolithotomy (PCNL) is considered to be the gold standard. This study aimed to investigate the efficacy and safety of mini-PCNL under total ultrasonography in patients aged <3 years.

Methods:

We reviewed 68 patients (80 renal units) aged <3 years between August 2006 and December 2014 in Peking University People's Hospital and Beijing Tsinghua Changung Hospital, including 36 renal units with a single stone, 6 with staghorn stones, 14 with upper ureteral stones, and 24 with multiple stones. The mean age of the patients was 24.2 months (range 6–36 months), and the mean maximum stone diameter was 19.2 mm (range 10–35 mm). The puncture site selection and tract dilation were guided by Doppler ultrasonography solely. All procedures were performed using 12–16 Fr tracts. Stones were fragmented using pneumatic lithotripsy and a holmium laser with an 8/9.8 Fr rigid ureteroscope.

Results:

Fifty-six patients with unilateral stones underwent a single session procedure, and 12 patients with bilateral stones underwent two procedures. The mean time to establish access was 2.8 min (range 1.8–5.0 min), the mean operative time was 36.5 min (range 20–88 min), the mean decrease in hemoglobin concentration was 8.9 g/L (2–15 g/L), and the stone-free rate (SFR) at hospital discharge was 94.0%. The mean postoperative hospital stay was 7.1 days (range 3–13 days). Postprocedure complications included fever (>38.5°C) in five patients and reactive pleural effusion in one patient. Blood loss requiring transfusion, sepsis, adjacent organ injury, and kidney loss were not observed.

Conclusions:

This study indicated that ultrasound-guided mini-PCNL is feasible and safe in patients aged <3 years, without major complications or radiation exposure.

Percutaneous nephrolithotomy in pediatric age group: Assessment of effectiveness and complications

Management of kidney stone disease in pediatric population is a challenging condition in urology practice. While the incidence of kidney stone is increasing in those group, technological innovations have conrtibuted to the development of minimally invasive treatment of urinary stone disease such as mini-percutenous nephrolitotomy (mini-PCNL), micro-PCNL, ultra mini-PCNL. In this review we tried to evaluate the effect of new teratment techniques on pediatric kidney stones.

Ultrasound-guided mini-percutaneous nephrolithotomy in patients aged less than 3 years: the largest reported single-center experience in China. Urolithiasis. 2015;Epub ahead of print. [PMID: 26232329 DOI: 10.1007/s00240-015-0809-x]

To investigate the efficacy and safety of mini-percutaneous nephrolithotomy (mini-PCNL) under total ultrasonography in patients aged <3 years.

METHODS

We reviewed 56 patients (67 renal units) aged <3 years between August 2006 and December 2012 in our units, including 31 renal units with a single stone, 6 with staghorn stones, 10 with upper ureteral stones, and 20 with multiple stones. The mean age of the patients was 24 (range 6-36) months and the mean maximum stone diameter was 18.9 (range 10-32) mm. The puncture site selection and tract dilation were guided by Doppler ultrasonography solely. All procedures were performed using 12-16 Fr tracts. Stones were fragmented using pneumatic lithotripsy and a holmium laser with an 8/9.8 Fr rigid ureteroscope. Forty-five patients with unilateral stones underwent a single procedure, and 11 patients with bilateral stones underwent two procedures. The mean time to establish access was 2.9 (range 2.1-5) min, the mean operative time was 36.8 (range 20-88) min, the mean decrease in hemoglobin concentration was 8.7 (2-15) g/L, and the stone-free rate at hospital discharge was 92.5%. The mean postoperative hospital stay was 7.1 (range 3-13) days. Post-procedure complications included fever (>38.5 °C) in four patients, and reactive pleural effusion in one patient. Blood loss requiring transfusion, sepsis, adjacent organ injury, and kidney loss were not observed. Ultrasound-guided mini-PCNL is feasible and safe in patients aged <3 years, without major complications or radiation exposure.

Single-stage multiple-tract percutaneous nephrolithotomy in the treatment of staghorn stones under total ultrasonography guidance

OBJECTIVE

To evaluate the safety and efficacy of single-stage multiple-tract percutaneous nephrolithotomy (PCNL) in the treatment of staghorn stones solely guided by ultrasonography (US).

PATIENTS AND METHODS

From May 2007 to July 2012, 55 single-stage multiple-tract PCNL procedures were performed (53 patients, of whom 2 had bilateral stones). Caliceal puncture and dilatation were performed under US guidance in all cases. The procedure was evaluated for access success, length of postoperative hospital stay, complications (modified Clavien system), and stone clearance.

RESULTS

The mean (±SD) operating time was 84.87 ± 24.9 min, with a mean (±SD) postoperative hospital stay of 5.2 ± 1.31 days. The patients experienced a mean (±SD) decrease in hemoglobin level of 8.23 ± 2.39 g/l and the stone-free rate after single-stage surgery was 78.18%. Extracorporeal shock wave lithotripsy was indicated in 2 cases as an auxiliary treatment. There were 10 grade 1 (62.5%) and 6 grade 2 (37.5%) complications; however, there were no complications above grade 3.

CONCLUSION

Total US-guided single-stage multiple-tract PCNL for treating staghorn calculi in selected cases is safe, feasible, and may be performed with an acceptable morbidity and with the advantage of preventing radiation hazards and damage to adjacent organs.

Does previous open nephrolithotomy affect the outcomes and complications of percutaneous nephrolithotomy in children?

OBJECTIVE

To analyze the success and complication rates of percutaneous nephrolithotomy (PCNL) performed in pediatric patients and to compare outcomes of the patients undergoing primary PCNL with those of patients who had undergone previous open nephrolithotomy.

MATERIALS AND METHODS

Between 2000 and 2011, PNL procedures were performed in 123 renal units (RU) of 111 children. We compared RU on which previous open surgery had been performed (group 1 RU = 26) on the same kidney with RU that had not been involved in previous surgery (group 2 RU = 97). Patient characteristics, pre- and postoperative hematocrit and creatinin levels, operative time, fluoroscopic screening time, stone free rate, complications and hospitalization time were documented and compared.

RESULTS

There were no significant differences between the groups in sex, stone burden, pre- and postoperative hematocrit levels. Mean age and pre- and postoperative creatinin levels were significantly higher in group 1 (p < 0.05). Mean operative time, fluoroscopic screening time and hospitalization times were similar in each group (p > 0.05). The stone free rates after PCNL were 65.4% in group 1 and 81.4% in group 2 (p > 0.05). Multiple access rate was higher in group 1; however, this was not statistically significant (27% vs. 15%, p > 0.05).

CONCLUSION

PCNL can be performed in pediatric patients who have previously undergone open nephrolithotomy but the success rates may be lower and risk of bowel injury higher. NCCT should be considered preoperatively for patients who have previously undergone open renal surgeries to investigate the presence of retrorenal colons. Our study includes relatively few patients with a history of open surgery and we believe that additional clinical studies with larger numbers of patients are needed to confirm our initial findings.

Does percutaneous nephrolithotomy and its outcomes have an impact on renal function? Quantitative analysis using SPECT-CT DMSA

To assess the functional effects of percutaneous nephrolithotomy (PCNL) and its outcomes in the operated kidney, we prospectively studied 30 consecutive cases undergoing PCNL. Kidney function was evaluated preoperatively and 3 months after surgery with serum creatinine, glomerular filtration rate (GFR), and with (99m)Tc-DMSA SPECT-CT scans to determine the differential renal function (DRF). PCNL effects in the operated kidney DRF were considered globally (DRFPLANAR, DRFSPECT) and in the region of percutaneous access (DRFACCESS). PCNL functional impact was also assessed depending on its outcomes, namely success (stone-free status) and the development of perioperative complications. PCNL has rendered 73 % of the cases completely stone free with a 33 % complication rate. After PCNL, serum creatinine and GFR did not change significantly, whereas DRFPLANAR and DRFSPECT dropped 1.2 % (p = 0.014) and 1.0 % (p = 0.041), respectively. The highest decrease was observed in DRFACCESS (1.8 %, p = 0.012). Stone-free status after PCNL did not show any impact on kidney function. Conversely, cases that suffered from a complication showed impairment in serum creatinine (0.1 mg/dL, p = 0.028), in GFR (11.1 mL/min, p = 0.036) as well as in DRFPLANAR (2.7 %, p = 0.018), DRFSPECT (2.2 %, p = 0.023) and DRFACCESS (2.7 %, p = 0.049). We conclude that PCNL has a minimal impact on global kidney function, which is mainly located in the region of percutaneous access. The advent of perioperative complications increased PCNL functional damage, whereas the stone-free status did not show any meaningful effect.

Minimally invasive percutaneous nephrolithotomy for simple and complex renal caliceal stones: a comparative analysis of more than 10,000 cases

PURPOSE

To determine whether minimally invasive PCNL (MPCNL) is as safe and effective in the management of complex renal caliceal stones as it is for simple renal stones.

PATIENTS AND METHODS

We retrospectively reviewed 5761(41.2%) simple caliceal stones (isolated renal pelvis including isolated calix) and 8223 (58.8%) complex caliceal stones (renal pelvis accompanying two calices at least) that were managed by MPCNL between 1992 nd 2011. The safety, efficacy, and outcome were compared and analyzed.

RESULTS

Stone burden was larger in complex caliceal stones (1763.0 vs 1018.6 mm(2), P<0.05). Patients with simple stones had significantly shorter operative time, less frequency of multiple percutaneous accesses, and less hemoglobin drop. They also had a higher initial stone-free rate (SFR) (77.6% vs 66.4%) after a single session of MPCNL (P<0.05). The differences diminished in the final SFR (86.7% vs 86.1%) after relook and/or auxiliary procedures (P>0.05). The complication rate (17.9% vs 19.0%) and blood transfusion rate (grade II) (2.2% vs 3.2%) were similar in both groups (P>0.05). Both groups had a low rate of high Clavien grade complications. Renal vascular embolizations (grade III), however, were significantly higher in patients with complex caliceal stones (P<0.05).

CONCLUSIONS

MPCNL is a safe and effective treatment option for patients with complex caliceal stones except there is a slightly higher frequency rate of embolization. There was a higher initial SFR in simple stones, but this difference diminished with secondary procedures.

The importance of instrument type in paediatric percutaneous nephrolithotomy

We reported our experience with percutaneous nephrolithotomy in children and compared the outcomes, including the morbidity and success rates, regarding the instruments of different sizes. One hundred and seventy-three paediatric patients, who underwent percutaneous nephrolithotomy in our clinic between 1999 and 2013, were assessed. According to the size of instruments used during surgery, three different groups were formed and the pre- and postopeartive outcomes were compared between the groups. 76 girls and 97 boys with a mean age of 9.24 (≤ 17) years were assessed. Stone-free rates were 75.6 % in group 1 (n = 82) using 17 F nephroscope, 79.4 % in group 2 (n = 73) using 24 F nephroscope and 72.2 % in group 3 (n = 18) using 26 F nephroscope. Postoperative fever was seen in four, five and one patient in group 1, 2 and 3, respectively. Urinary infection was seen in one patient in group 1 and four patients in group 2. Mean haematocrit drop and stone burden were significantly lesser in group 1. No significant difference was seen in the duration of nephrostomy and hospitalization between the groups. The success rates obtained in the groups using different instrument types (paediatric or adult) were similar. However, age, weight, height, stone burden and bleeding were significantly lesser in group 1 that used paediatric type of instrument. As the most frequent complication of PNL, bleeding seems to be associated with stone burden, the diameter of dilatation and the calibre of instrument. To decrease the particular complications, paediatric type of instruments are convenient and do not affect the success.

Safety and efficacy of percutaneous nephrolithotomy for the treatment of paediatric urolithiasis

INTRODUCTION

Paediatric percutaneous nephrolithotomy (PCNL) has revolutionised the treatment of paediatric nephrolithiasis. Paediatric PCNL has been performed using both adult and paediatric instruments. Stone clearance rates and complications vary according to the technique used and surgeon experience. We present our experience with PCNL using adult instruments and a 28Fr access tract for large renal calculi in children under 18 years.

METHODS

All patients undergoing PCNL at our institution between 2000 and 2009 were reviewed. Demographics, surgical details and post-operative follow-up information were obtained to identify stone clearance rates and complications.

RESULTS

PCNL was performed in 32 renal units in 31 patients (mean age: 10.8 years). The mean stone diameter was 19mm (range: 5-40mm). Twenty-six cases required single puncture and six required multiple tracts. Overall, 11 staghorn stones, 10 multiple calyceal stones and 11 single stones were treated. Twenty-seven patients (84%) were completely stone free following initial PCNL. Two cases had extracorporeal shock wave lithotripsy for residual fragments, giving an overall stone free rate of 91% following treatment. There was no significant bleeding or sepsis encountered either during the operation or in the post-operative setting. No patient required or received a blood transfusion.

CONCLUSIONS

Paediatric PCNL can be performed safely with minimal morbidity using adult instruments for large stone burden, enabling rapid and complete stone clearance.

Chinese minimally invasive percutaneous nephrolithotomy for intrarenal stones in patients with solitary kidney: a single-center experience

OBJECTIVE

To report our experience with Chinese minimally invasive percutaneous nephrolithotomy (Chinese MPCNL) to manage patients with intrarenal stones in solitary kidney, and evaluate the safety, efficiency and feasibility of this technique.

METHODS

Forty-one patients with intrarenal stones in solitary kidney underwent Chinese MPCNL in our department from March 2009 to February 2011. Demographic characteristics, operative parameters, number of tracts, stone-free rates (SFRs), stone analyses, hemoglobin levels, nephrostomy tube removal time, hospitalization time, and complications were evaluated. Serum creatinine (Scr) and glomerular filtration rate (GFR) were measured preoperatively, postoperatively at 1 month, and each follow-up visit. The 5-stage classification of chronic kidney disease (CKD) was used according to the National Kidney Foundation guidelines.

RESULTS

The initial stone-free status was achieved in 35 (85.4%) patients after Chinese MPCNL. The mean follow-up time was 16.9 ± 4.7 months (range: 12-24), and the final SFR improved to 97.6% after auxiliary procedures. Among all patients, complex stones were detected in 26 (63.4%) patients, and 9 (22.0%) required multiple tracts. The mean operative time and mean hospitalization time were 71.3 ± 23.5 min (range: 40-139) and 6.1 ± 0.5 days (range: 5-11), respectively. During preoperative period and postoperative period (1 month), Scr were 132.1 ± 41.3 umol/L (range: 78.2-231.4) and 108.9 ± 30.7 umol/L (range: 71.6-136.9), respectively (P<0.05), while GFR were 74.9 ± 24.2 ml/min (range: 35-110) and 83.9 ± 27.4 ml/min (range: 65-110), respectively (P<0.05). According to CKD classification, the renal function was stable, improved, and worse in 29 (70.7%), 11 (26.8%), and 1 (2.5%) patients, compared with the preoperative levels. No patient progressed to end-stage renal disease requiring dialysis.

CONCLUSIONS

Our experience with Chinese MPCNL demonstrates that it is safe, feasible and efficient for managing the intrarenal calculi in solitary kidney with a low complication rate. At long-term follow-up, renal function stabilized or even improved in the majority of patients with solitary kidney.

Long-term outcomes of percutaneous nephrolithotomy in 177 patients with chronic kidney disease: a single center experience

PURPOSE

We evaluated the long-term outcomes of percutaneous nephrolithotomy in patients with chronic kidney disease.

MATERIALS AND METHODS

Data on 1,904 patients who underwent percutaneous nephrolithotomy between 2002 and 2011 were retrospectively collected. The estimated glomerular filtration rate for each patient was retrospectively calculated using a 4-variable modification of diet in renal disease equation. Patients were staged for chronic kidney disease by National Kidney Foundation guidelines.

RESULTS

A total of 242 patients (12.7%) had a preoperative glomerular filtration rate of less than 60 ml per minute/1.73 m(2). Those monitored a minimum of 1 year were included in analysis. The study included 177 patients with a mean ± SD age of 54.3 ± 12.1 years. Perioperative and postoperative complications were noted in 15.2% of patients. At a mean followup of 43.4 ± 22.7 months renal function in 29.4% of patients had improved but it remained the same or deteriorated in 54.2% and 16.4%, respectively. On multivariate regression analysis diabetes and preoperative or postoperative complications predicted renal function. The stone-free rate 3 months postoperatively was 80.2% (142 of 177 cases). Stones recurred during long-term followup in 36 of these patients (25.3%). Spontaneous stone passage was detected in 12 of the 35 patients (34.2%) with residual stones but 8 (22.8%) with residual stones experienced an increase in stone size.

CONCLUSIONS

At long-term followup renal function was maintained or improved in greater than 80% of patients with chronic kidney disease who underwent percutaneous nephrolithotomy. Stones recurred or residual stones grew in approximately 25% of these patients.

Renal parenchymal damage after percutaneous nephrolithotomy with one-stage tract dilation technique: a randomized clinical trial

PURPOSE

To compare the effects of one-stage vs gradual dilation techniques during percutaneous nephrolithotomy (PCNL) on postoperative renal scar formation and overall renal function.

PATIENTS AND METHODS

Of 152 adult patients who underwent surgery during the study period, 48 were randomized into two groups. In group 1 (n=19), gradual tract dilation with Alken metallic dilators was used, and in group 2 (n=29), one-stage tract dilation was used. We compared patient demographics, intraoperative and preoperative parameters, postoperative overall renal function, and renal scar formation on the target renal pole.

RESULTS

Access time (P=0.001; 95% confidence interval [CI]: 3.19-6.30) and radiation exposure during access (P=0.03; 95% CI: 0.03-0.66) were significantly shorter in group 2. In group 1, the decrease in mean technetium-99m dimercaptosuccinic acid (99m-Tc DMSA) uptake from 44.1±20.1% to 43.4±19.6% 4 weeks postoperatively (-0.7%±0.5%; P=0.27; 95% CI: -0.56-1.93) was not significant. In group 2, however, there was a significant decrease in post-PCNL 99m-Tc DMSA uptake 2 (-2.4±0.3%, from 50.1±13.5% to 47.7±13.8%; P=0.001; 95% CI: 1.13-3.66). Four weeks after surgery, new scar formation or progression of the preoperative scar at the site of access were seen in 14 of 29 (48.3%) patients who were treated with one-stage dilation whereas only 2 of 19 (11.0%) patients who were treated with gradual dilation developed new scarring at the access site (P=0.007).

CONCLUSION

Although the one-stage tract dilation technique reduced radiation exposure and access time, in the short term, it may cause more parenchymal damage than the gradual dilation technique.

Impacts of percutaneous nephrolithotomy on the estimated glomerular filtration rate during the first few days after surgery

Long-term effects of percutaneous nephrolithotomy (PCNL) on renal function have been evaluated in many studies but there are little data on the renal effects of PCNL immediately after surgery in human patients. The aim of this study was to evaluate estimated glomerular filtration rate (GFR) during the first few days after PCNL. From July to September 2008, we gathered preoperative and postoperative serum creatinine data of all the patients who underwent PCNL at our center. Children and patients who received transfusion during surgery were excluded. Creatinine clearance was estimated by Cockcroft-Gault equation and was used to estimate GFR. 94 patients met the inclusion criteria. The mean ± SD of creatinine clearance by Cockcroft-Gault equation was 87.5 ± 32.2 cc/min before operation. It decreased to 85.5 ± 29.4 cc/min, 77.0 ± 26.8 cc/min and 75.9 ± 25.0 cc/min at 6, 24 and 48 h after operation and then increased slightly to 81.9 ± 26.4 cc/min 72 h after operation. Renal GFR decreases immediately after PCNL reaches a nadir 48 h after operation, and then, increases slowly. It seems advisable to avoid factors that can bear a negative influence on renal function during the early postoperative period such as nephrotoxic drugs, contrast agents, shock wave lithotripsy and Re-PCNL.

Comparison of outcomes after percutaneous nephrolithotomy of staghorn calculi in those with single and multiple accesses

PURPOSE

To analyze the early outcome after single tract vs multiple tracts percutaneous nephrolithotomy (PCNL) in the management of staghorn calculi.

PATIENTS AND METHODS

The records of 413 patients with staghorn calculi (223 [54%] had complete and 190 [46%] had partial) who underwent PCNL were reviewed retrospectively. A total of 244 (59%) patients were managed by single access (group 1); meanwhile, multiple accesses were necessary in 169 (41%) patients (group 2). Both groups were compared in terms of perioperative findings and postoperative outcomes. Patients and stone-related factors affecting the number of accesses performed were analyzed.

RESULTS

The mean number of percutaneous accesses was 2.42 +/- 0.74 (range 2-6) in group 2. Mean durations of fluoroscopy screening time and operative time were significantly longer in group 2 (P = 0.002, P < 0.0001, respectively). Supracostal access was necessary in 30.7% in group 2 and in 6.9% in group 1 (P = 0.001). Success was achieved in 70.1% in group 1 and in 81.1% for group 2 after one session of PCNL (P = 0.012). The most common complication was bleeding for both groups, and it was higher in group 2 (P < 0.0001). The mean preoperative and postoperative creatinine concentrations were 1.03 mg/dL and 1.08 mg/dL in group 1, and 0.9 mg/dL and 1.03 mg/dL in group 2, respectively. The mean changes in creatinine values were not statistically significant between the groups (P = 0.16).

CONCLUSIONS

The impact of PCNL using either single or multiple access tracts on renal function is similar and of a temporary nature. PCNL with multiple accesses is a highly successful alternative with considerable complication rates in the management of staghorn calculi.

Safety and efficacy of percutaneous nephrolithotomy in infants, preschool age, and older children with different sizes of instruments

OBJECTIVES

To compare the morbidity and success rates among different age groups of children undergoing percutaneous nephrolithotomy (PCNL) using adult- or pediatric-sized devices. PCNL for renal stones in children may present problems because of small size, mobility of the pediatric kidney, and the small size of the collecting system.

METHODS

Patients were categorized into 2 age groups: those < or =7 years old at the time of PCNL (group 1, n = 17 [38.6%]), and those 8-16 years old (group 2, n = 27 [61.4%]). Group 2 children were further divided into subgroups according to the use of pediatric- (group 2a, n = 12 [27.3%]) or adult-sized devices (group 2 b, n = 15 [34.1%]).

RESULTS

Mean patient age was 4.1, 11.7, and 13.2 years in groups 1, 2a, and 2b, respectively. Fluoroscopy time, time to access the collecting system, operative time, and average postoperative hospital stay did not differ between the groups. However, hemoglobin decrease, bleeding during surgery, and blood transfusion rate was higher in group 2b. Stones were completely cleared in 82.4%, 83.3%, and 81.3% patients, and these percentages increased to 94.1%, 91.7%, and 93.7% with adjunctive shock wave lithotripsy and ureterorenoscopy in groups 1, 2a, and 2b, respectively.

CONCLUSIONS

Endourologic intervention in children usually requires instruments specific for preschool age; however, in older children with dilated collecting system, the use of adult instruments and techniques may achieve equal results.