Percutaneous nephrolithotomy in children: lessons learned in 5 years at a single institution

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study

Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.

Is percutaneous nephrolithotomy effective and safe in infants younger than 2 Years old? Comparison of mini standard percutaneous nephrolithotomy

BACKGROUND

In this study, we aimed to compare the operative outcomes, postoperative outcomes, stone-free status and complications of SPCNL and MPCNL in infants younger than two years of age.

METHODS

We retrospectively analyzed 163 patients younger than two years of age who underwent percutaneous nephrolithotomy (PCNL) in our institution between September 1999 and March 2022. The patients were divided into two groups depending on the tract size. The MPCNL group consisted of 73 patients with a tract of 22 Fr or less, and the SPCNL consisted of 90 patients with a tract greater than 22 Fr.

RESULTS

The median age of 163 patients included in the study was 17.3 (range 7-24) months. Although the median stone size was lower in the SPCNL group, no statistically significant difference was found between the two groups in terms of stone size (p = 0.073). The median operative time was 74.8 min in the MPCNL group and 62.8 min in the SPCNL group, with a statistically significant difference (p = 0.002). Stone free rates (SFR) were 89 % and 90.8 % in the MPCNL and SPCNL groups, and the clinically insignificant residual fragments (CIRF) rates were 11 % and 4.6 %, respectively (p = 0.064). The fluoroscopy time, nephrostomy withdrawal time, and hospitalization stay were similar in the two PCNL groups (p = 0.535, p = 0.253, and p = 0.143, respectively). Postoperative fever was similar in MPCNL and SPCNL groups (p = 0.504). Although bleeding (6.7%-2.7 %) and blood transfusion (3.3%-1.4 %) rates were higher in the SPCNL group, there was no statistically significant difference (p = 0.248 and p = 0.420, respectively). Prolonged urinary leakage occurred in 6 (8.2 %) patients in the MPCNL group and 1 (1.1 %) patient in the SPCNL group, with a statistically significant difference (p = 0.026).

CONCLUSIONS

With the development of MPCNL, the use of SPCNL in infants has decreased considerably. However, SPCNL continues to be an effective and reliable method when needed in suitable patients. Although PCNL in infants shows some differences from adults, it is an effective and safe method for suitable patients.

LEVEL OF EVIDENCE

Although we created our study by retrospectively examining the pediatric urology data that we created prospectively, our study is of a retrospective nature. Therefore the Level of Evidence is 3.

Comparison of two percutaneous nephrolithotomy methods for the treatment of pediatric kidney stones: mini-percutaneous nephrolithotomy and standard percutaneous nephrolithotomy

OBJECTIVE

In this study, the aim was to compare the results of mini and standard percutaneous nephrolithotomy (PCNL) for the treatment of pediatric kidney stones.

MATERIALS AND METHODS

Data for 128 patients < 18 years of age who underwent mini and standard PCNL due to pediatric kidney stones were retrospectively examined. Patients were divided into two groups: mini-PCNL (16-20 Fr) and standard PCNL (26 Fr). Surgery time, number of punctures to the pelvicalyceal system, hospital stay, postoperative hemoglobin drop, complications and stone-free status (SFR) were compared between the groups. Additional surgical intervention (double-J stent, ureterorenoscopy, secondary PCNL) performed after the surgery was recorded. The absence of residual stones or < 3 mm residual stones on kidney, ureter and bladder radiography (KUB) and ultrasonography (USG) performed in the third postoperative month were accepted as success criteria.

RESULTS

There were 32 (43.8%) patients in the mini-PCNL group and 41 (56.2%) patients in the standard PCNL group. The mean age was 9.3 ± 4.1 years in the mini-PCNL group and 10.1 ± 5.4 years in the standard PCNL group. Mean stone size in the mini-PCNL group was 2.1 ± 1.2; while for standard PCNL it was 2.3 ± 1.4. The mean surgery time was statistically significantly higher in the mini-PCNL group (p = 0.005). There was no difference between the groups in terms of intraoperative double J stent use, postoperative complications and SFR. A double J stent was inserted in two patients in the mini-PCNL group and in one patient in the standard PCNL group due to urine leakage from the nephrostomy tract in the postoperative period. Although the postoperative hemoglobin drop was found to be significantly higher in standard PCNL (p = 0.001), hematuria and blood transfusion rates were low in both groups. Mean hospital stay was shorter in the mini-PCNL group compared to standard PCNL (3.6 ± 1.2 days vs. 2.5 ± 1.1; p = 0.018).

CONCLUSIONS

Although mini-PCNL has longer surgery time compared to standard PCNL, it should be preferred for the treatment of pediatric kidney stones due to advantages such as similar success and complication rates to standard PCNL, short hospital stay and less postoperative hemoglobin drop.

Outcomes of ultraminipercutaneous nephrolithotomy in infants: our experiences at a single center in an endemic region

OBJECTIVE

In this study, we aimed to contribute to the literature by sharing the perioperative and postoperative outcomes of infants (0-24 months) who underwent ultra-mini percutaneous nephrolithotomy (PNL) for kidney stones in our clinic.

METHODS

Infants under 24 months old with kidney stones of 2 cm and larger, who applied to our clinic between January 2018 and May 2023, were included in the study. The patients' demographic and clinical characteristics were obtained from the medical records. The collected data were analyzed retrospectively.

RESULTS

A total of 26 patients were included in the study. The mean age of the patients was 17.3 ± 3.90 (12-24) months. The mean operation time was 50.7 ± 6.43 min. The mean stone size was 2.66 ± 0.59 cm. Stone-free was achieved in 23 patients (88.5%). In one patient (3.8%) with residual fragments, SWL was performed, and in two patients (7.7%), RIRS was performed to achieve stone-free. Postoperatively, fever was observed in 3 patients (11.5%). There were no patients requiring blood transfusion.

CONCLUSIONS

In experienced centers, ultra-mini-PNL performed by experienced surgeons is an effective and reliable treatment option for infants under 24 months of age with kidney stones larger than 2 cm. It provides high-stone clearance rates and low complication rates.

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.

Feasibility, safety, and effectiveness of adult-sized instruments in pediatric percutaneous nephrolithotomy: A systematic review and meta-analysis

INTRODUCTION

Little evidence exists regarding the benefits and disadvantages of adult-sized instruments for Percutaneous Nephrolithotomy (PCNL) in pediatric patients. This systematic review aims to clarify the safety and efficacy of this approach.

MATERIALS AND METHODS

We conducted a systematic literature review using databases of PubMed, Scopus, Embase, Web of Science, and Cochrane and included studies that evaluated PCNL in children. All identified records underwent two-phase title/abstract and full-text screening. Pediatric patients were defined as 17 years or younger, and adult-sized instruments as 24Fr and above. The primary outcomes were success (stone-free) rate and surgical complications obtained from studies comparing adult-sized and pediatric-sized instruments.

RESULTS

A total of 84 abstracts and 16 full text article were assessed till July 2021 and 6 studies were included. All studies were retrospective. Number of accesses (Odds ratio (OR), adult-sized to pediatric-sized: 0.96, 95% CI: 0.52-1.78, p = 0.89), initial stone-free rate (OR: 0.73, 95% CI: 0.42-1.27, p = 0.26), final stone-free rate (OR: 1.14, 95% CI: 0.38-3.44, p = 0.82), and residual stones (OR: 0.79, 95% CI: 0.42-1.49, p = 0.46) could be analyzed, none with significant differences. Overall complication rates did not differ significantly between the groups. However, one study reported more grade III/IV complications in the adult-sized instrument group. The adult-sized instrument group had a higher hemoglobin/hematocrit decrease in 3 studies. Duration of surgery, fluoroscopy time, length of hospital stay, times to nephrostomy tube removal, and transfusion rate could not be assessed in meta-analysis; however, they were comparable between the adult-sized and pediatric-sized groups. Studies also showed that adult-sized instruments are applicable in children younger than 3 years and those with staghorn calculi as well as in fluoroscopy-free ultrasound-guided PCNL.

CONCLUSION

Adult-sized instruments had comparable outcomes to the pediatric-sized ones and can be applied in pediatric PCNL when factors such as accessibility justify their use. The number and design of the studies restrict the reliability of the comparisons. Therefore, future studies with improved methodology may better reveal the impact of instruments on the outcome of PCNL in children.

Primary hyperoxaluria type 1: urologic and therapeutic management

While the surgical approaches available in primary hyperoxaluria (PH) are common to all patients requiring intervention for urolithiasis, the indications for treatment and their corresponding toxicities are unique. Being a rare disease, we are guided by case series. This review summarizes the available literature highlighting the important disease-specific considerations. Shockwave lithotripsy (SWL) is of particular interest. It is generally the first-line treatment for stones in children, but here the stones produced will be relatively resistant to fragmentation. In addition, there are concerning reports in children of sudden unilateral decline in function in the treated kidney as measured by nuclear renography. Percutaneous nephrostolithotomy might intuitively seem favorable given the shortest drain duration and the ability to treat larger stones efficiently but, similar to SWL, rapid chronic kidney disease (CKD) progression has been seen postoperatively. Ureteroscopy is therefore generally the safest option, but considerations regarding stent encrustation, the growth of residual fragments and the large volume of stone often faced may limit this approach. The surgeon must balance the above with consideration of the patient's CKD status when considering a plan of monitoring and treating stones in PH.

Outcomes of Mini-Percutaneous Nephrolithotomy in Children and Adolescents: A 10-Year Single-Centre Experience From Kuwait

The current study retrospectively reviewed data for all children and adolescents who underwent mini-percutaneous nephrolithotomy (PCNL) at Ibn Sina Hospital and Sabah Al Ahmad Urology Centre in Kuwait over 10 years. Accordingly, the 40 patients underwent mini-PCNL. Among them, 21 patients (52.5%) had varying degrees of hydronephrosis, with mild to moderate severity accounting for nearly half of them, whereas six (15%) had multiple stones. The median operative time was 54.5 (43.3-64) minutes. Moreover, 11 patients needed flexible ureteroscopy (URS) and double-J (DJ) ureteric stent, and one patient required DJ ureteric stent only. None of the cases developed intraoperative bleeding. The median hospital stay of the included patients was three (2.3-4) days. Residual stone was observed in 11 patients (27.5%), with a median size of 3 (2 to 7) mm. The incidence of postoperative complications was 27.5% (n = 11 patients), with three patients experiencing postoperative bleeding (7.5%) and eight patients developing a fever (20%). All patients had mild postoperative pain. However, no leakage, sepsis, or pelvic injury occurred. None of the patients required revision. In conclusion, mini-PCNL was a safe and effective procedure in children and adolescents with renal stones.

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.

Minimally invasive surgery for pediatric renal and ureteric stones: A therapeutic update

The incidence of pediatric urolithiasis (PU) is growing worldwide. The corresponding therapeutic methods have become a research hot spot in pediatric urology. PU has the characteristics of abnormal metabolism, easy recurrence, and immature urinary system development, which make its treatment different from that of adults. Pediatric urologists should select the optimal treatment modality to completely remove the stones to prevent recurrence. Currently, the curative treatments of PU include extracorporeal shock wave lithotripsy (ESWL), ureteroscopy, retrograde intrarenal surgery, percutaneous nephrolithotomy (PCNL), laparoscopic, robot-assisted laparoscopic, and open surgery. This review aims to conduct a therapeutic update on the surgical interventions of both pediatric renal and ureteric stones. It accentuates that pediatric surgeons or urologists should bear in mind the pros and cons of various minimally invasive surgical treatments under different conditions. In the future, the treatment of PU will be more refined due to the advancement of technology and the development of surgical instruments. However, a comprehensive understanding of the affected factors should be taken into account by pediatric urologists to select the most beneficial treatment plan for individual children to achieve precise treatment.

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.

Comparison of super-mini versus mini percutaneous nephrolithotomy for the treatment of upper urinary tract stones in children: a single centre experience

PURPOSE

The efficacy and safety of super-mini percutaneous nephrolithotomy (SMP, 14 Fr) was compared with mini percutaneous nephrolithotomy (MPCNL, 16 Fr) for the treatment of upper urinary tract stones in children (< 14 years old).

METHODS

Clinical data of 133 paediatric patients with upper urinary tract stones treated with SMP or MPCNL between May 2012 and May 2019 were retrospectively analysed. The patients were divided into the SMP and MPCNL groups. Age, height, weight, stone size, operation time, stone-free rate (SFR), postoperative complications, tubeless rate, and length of postoperative hospital stay (LOS) were compared.

RESULTS

There were 66 patients (49.6%) in the SMP and 67 patients (50.4%) in the MPCNL group. No significant difference in the median age, weight, height and operation time, and SFR existed between the patients of the two groups. Larger stones were removed via SMP compared to those removed with MPCNL (2.0 vs. 1.5 cm, P = 0.001). LOS for SMP patients was significantly lower than that for the MPCNL patients (2 and 6 days, respectively, P < 0.0001). The tubeless rate for SMP was significantly higher than that for MPCNL (100% vs. 0%, P < 0.0001). Total complication rate of MPCNL was significantly higher than that of SMP (25.3% vs. 7.5%, P = 0.006). No patient required blood transfusion, and septicaemia, and other serious complications did not occur.

CONCLUSION

SMP is more effective than MPCNL for treating middle-sized upper urinary tract stones in children, and is associated with a shorter LOS and a higher tubeless rate.

Changes in percutaneous approach to kidney stones in children: A single institute experience over 500 cases

PURPOSE

The aim of this study is to identify the changes in patient age and stone sizes with technological advancement over time.

METHODS

This study was conducted retrospectively with 404 patients (504 renal units) who underwent percutaneous nephrolithotomy (PCNL) between January 1997 and June 2020. Patient characteristics and trends on instrument preferences were investigated.

RESULTS

Median age was 7 (1-18) years. Male to female ratio was 1.48:1 (301/203). Median stone burden was 2 cm² (0.20-25) and median operative time was 90 minutes (20-240). The stone-free rate was 74.6%. Patients were divided into four groups according to the size of the instrument. It was found that the size of sheath used increased significantly with increasing age and stone burden. The micro-PCNL group had the shortest hospitalisation and lowest blood transfusion rate. Chronologically categorised four equal groups were compared to analyse changing patient profiles and trends. Median patient age, stone burden, operation time, sheath size, blood transfusion and complication rates decreased significantly with time. However, the use of tracts smaller than 20F and the number of patients with previous intervention increased significantly.

CONCLUSION

Our study demonstrated that the patient's age and stone size at the time of initial diagnosis decrease over time while miniaturisation techniques increase in paediatric urology.

Mini-percutaneous nephrolithotomy in a child with multiple urogenital anomalies and a solitary duplex kidney

Purpose:

To report a case of successful removal of right staghorn renal calculi in a 3-year-old girl with Arnold-Chiari malformation and multiple urogenital anomalies.

Case report:

A 3-year-old female child with the diagnosis of Arnold-Chiari type 2 malformation was referred to our clinic due to presence of 9 kidney stones with a total volume of 10743mm3. The total of the longest diameters of all stones was calculated as 11.4cm. The patient had a urogenital septum, bifid bladder, and duplicated collecting system on the right side. An 18F Amplatz sheath was placed and mini-percutaneous nephrolithotomy was performed successfully by laser and pneumatic lithotripter. Any residual urinary tract stones or urinary tract infection were not detected during the 6th-month follow-up.

Conclusion:

Urolithiasis requires a thorough understanding of the underlying causes, as well as an effective and minimally invasive treatment. It is important for urologists to understand the complexity of the optimal stone management in pediatric patients in order to maximize treatment efficacy and minimize morbidity. We conclude that it is essential to treat urolithiasis in a single session in children with urogenital anomalies and accompanying congenital anomalies who have past surgical history.

Classification and standardized reporting of percutaneous nephrolithotomy (PCNL): International Alliance of Urolithiasis (IAU) Consensus Statements

BACKGROUND

The aim of this study was to reach a consensus in the classification and standardized reporting for the different types of PCNLs.

METHODS

The RAND/UCLA appropriateness methodology was used to reach a consensus. Thirty-two statements were formulated reviewing the literature on guidelines and consensus on PCNLs, and included procedure specific details, outcome measurements and a classification for PCNLs. Experts were invited to two rounds of input, the first enabled independent modifications of the proposed statements and provided the option to add statements. The second round facilitated scoring of all statements. Each statement was discussed in the third round to decide which statements to include. Any suggestion or disagreement was debated and discussed to reach a consensual agreement.

RESULTS

Twenty-five recommendations were identified to provide standardized reporting of procedure and outcomes. Consensual scoring above 80% were strongly agreed upon by the panel. The top treatment related outcomes were size of sheath used (99.1%) and position for PCNL (93.5%). The highest ranked Outcome Measures included definition of postoperative hospital length of stay (94.4%) and estimated blood loss (93.5%).

CONCLUSIONS

The consensus statements will be useful to clarify operative technique, in the design of clinical trials and standardized reporting, and presentation of results to compare outcomes of different types of PCNLs.

Can ultrasound guidance reduce radiation exposure significantly in percutaneous nephrolithotomy in pediatric patients?

In this study, we aimed to compare clinical and technical outcomes between pediatric patients who underwent percutaneous nephrolithotomy (PCNL) under fluoroscopy (FL) and those that underwent this procedure under FL with ultrasound assistance (FLUSA). The data of 66 PCNL patients were analyzed retrospectively. Renal puncture was successful in 22 patients in the FLUSA group and 44 patients in the FL group. In all cases, FL was used for tract dilation and confirmation of ureteral catheter positioning at the beginning of the procedure. The sample consisted of 46 males and 20 females with a mean age of 7.2 ± 2.1 years (range 1-17 years). Stone size varied from 8.0 to 75.4 mm, and 89% of patients achieved a completely stone-free state. The median puncture time was 130.5 ± 25.3 s for FLUSA and 295 ± 82.8 s for FL, the median fluoroscopic screening time was 95 ± 33 and 230 ± 116 s, respectively, and the median radiation dose was 19.04 ± 9.9 dGy/cm² and 54 ± 21.4 dGy/cm², respectively. The median puncture time, fluoroscopic screening time, and radiation dose were statistically lower in the FLUSA group (p = 0.001, Mann-Whitney U test). The greatest problem in PCNL is the use of fluoroscopy. Due to some anatomical differences from adults, applying PCNL in pediatric patients using only ultrasound may decrease the success rate. Puncture with ultrasound significantly reduces the radiation dose in children. Puncture with ultrasound and dilation under fluoroscopy is a successful and safe treatment method with low morbidity and high success rates and shorter hospital stay in pediatric patients.

Nomograms predicting the outcomes of endoscopic treatments for pediatric upper urinary tract calculi

OBJECTIVES

To demonstrate the efficacy and safety of mini-percutaneous nephrolithotomy, micro-percutaneous nephrolithotomy, and flexible ureteroscopy for pediatric upper urinary tract calculi and to develop nomograms predicting surgical outcomes.

METHODS

A prospectively managed database containing children who were diagnosed with upper urinary tract calculi and treated with mini-percutaneous nephrolithotomy, micro-percutaneous nephrolithotomy, and flexible ureteroscopy between June 2014 and April 2019 was analysed. Patient demographics, intraoperative data, stone characteristics, stone-free rate, and complication rate were analysed and compared. Nomograms predicting the postoperative stone-free rate and complication rate were established based on predictors, and internal validation was performed. Calibration curves and decision curves were generated to assess the predictive efficacy and clinical benefit.

RESULTS

Forty-three children underwent mini-percutaneous nephrolithotomy on 56 sides in 47 operations, 30 children underwent micro-percutaneous nephrolithotomy on 30 sides in 30 operations, and 275 children underwent flexible ureteroscopy on 320 sides in 288 operations. The stone-free rates were 88.5% (282/320) for flexible ureteroscopy, 89.3% (50/56) for mini-percutaneous nephrolithotomy, and 90.0% (27/30) for micro-percutaneous nephrolithotomy (P = 0.94). And the complication rates were 19.8% (57/288), 36.2% (17/47), and 33.3% (10/30), respectively (P = 0.02). Nomograms based on stone characteristics, operation duration, and the physical condition of the child were shown to have good discrimination and calibration. The area under the curve of the models was 81% for stone-free rate and 73% for complication rate. The calibration curves showed that the nomogram might underestimate the probability of stone-free rate when the threshold was below 82% and might overestimate the risk of complication rate when the threshold was over 25%. The decision curves demonstrated that the Capital Medical University nomograms improved clinical risk prediction against threshold probabilities of stone-free rate ≤20% and complication rate ≤10%.

CONCLUSIONS

Both the percutaneous nephrolithotomy and flexible ureteroscopy procedures could have acceptable stone-free rates when treating pediatric stones. The Capital Medical University nomograms performed well in helping to predict stone-free and complication rates.

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.

Tubeless PNL can safely be applied to selected patients in pediatric stone disease

OBJECTIVE

The purpose of this study was to compare the results of tubeless percutaneous nephrolithotomy (TPNL) and standard percutaneous nephrolithotomy (SPNL) for the management of nephrolithiasis in children.

MATERIAL AND METHODS

The data for 48 patients aged lesser than 18 years who underwent percutaneous nephrolithotomy (PNL) between January 2010 and June 2018 were reviewed retrospectively. The patients were classified into 2 categories depending on tube placement. A total of 21 patients were treated with TPNL and 27 with SPNL technique. The surgical method employed was selected depending on intraoperative complications. The size of the endoscopic instrument (mini/standard) to be used was decided according to the stone burden and surgeon preference.

RESULTS

A complete stone-free rate (SFR) was achieved in 85.7% (n=18) of the TPNL group and 85.2% (n=23) of the SPNL group (p=0.959). In the TPNL group, two patients with clinically significant stones underwent retrograde intrarenal surgery, and one patient with clinically insignificant residual stone remained under follow-up. In the SPNL group, two patients with clinically significant stones underwent repeat mini-PNL surgery, the stones being fragmented with shock wave lithotripsy in one patient, and 1 one patient with insignificant residual stone remained under follow-up. No significant differences were observed in terms of intraoperative and postoperative complications, mean SFRs, or operative and fluoroscopy times. However, a statistically significant difference was observed in lengths of hospital stay (p<0.001).

CONCLUSION

TPNL is a safe and effective procedure in children. No significant difference was found between TPNL and SPNL in terms of stone clearance; however, patients undergoing TPNL had significantly shorter hospital stays.

Critical Application of Adult Nephrolithometric Scoring Systems to Children Undergoing Mini-Percutaneous Nephrolithotomy

Objective: To evaluate and compare the ability of the Guy's stone score (GSS), the S.T.O.N.E. nephrolithometry, and the Clinical Research Office of the Endourology Society (CROES) nomogram to predict the outcome of mini-percutaneous nephrolithotomy (MPNL) in children, and to identify which of the predictors involved in these scoring systems can separately affect this outcome. Patients and Methods: All children younger than 14 years who had MPNL in our center over a period of 3 years were included prospectively. Bivariate analyses were done to evaluate the associations of the three scoring systems and the predictors composing them with single-session stone clearance and complications. Receiver operating characteristic (ROC) curve analyses of the three scoring systems were conducted to evaluate and compare their abilities to predict the outcomes. Decision curve analyses for the three scoring systems were conducted to evaluate the clinical benefit of using each of them to predict stone clearance. Results: We consecutively enrolled 92 renal units in 89 children with a median age of 9.5 years. Single-session stone clearance was achieved in 76 (82.6%) renal units. Complications occurred with 19 (20.7%) procedures. Stone multiplicity (p = 0.043), staghorn stone (p = 0.007), prior stone treatment (p < 0.001), number of calices involved (p = 0.006), stone burden (p = 0.003), GSS (p < 0.001), S.T.O.N.E. nephrolithometry (p = 0.012), and CROES nomogram (p < 0.001) had significant associations with stone clearance. Only stone attenuation was significantly associated with complications (p = 0.031). For prediction of stone clearance, CROES nomogram demonstrated the greatest area under the ROC curve and the greatest net benefit on decision curve analyses. Conclusions: For children undergoing MPNL, CROES nomogram is the best to predict stone clearance. However, none of the studied scoring systems predicted complications efficiently.

Management of staghorn stones in special situations

Staghorn stones have always been a challenge for urologists, especially in some special situations, such as horseshoe kidney, ectopic kidney, paediatric kidney, and solitary kidney. The treatment of these staghorn stones must be aggressive because they can lead to renal function loss and serious complications. The gold-standard management for staghorn stones is surgical treatment with the aim of clearing the stones and preserving renal function. Treatment methods for staghorn stones have developed rapidly, such as extracorporeal shock wave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy and laparoscopy and open surgery. Whether the standard procedures for staghorn stones can also apply to these stones in special situations is still not agreed upon. The decision should be made individually according to the circumstances of the patient. In this review, we evaluates the previous studies and comments on the management of staghorn stones under special situations in the hope of guiding the optimal choice for urologists.

Technique, complications, and outcomes of pediatric urolithiasis management at a tertiary care hospital: evolving paradigms over the last 15 years

BACKGROUND

Despite technological advancements, there is lack of consensus for the standard treatment modalities for pediatric urolithiasis.

OBJECTIVE

The primary objective was to review the management of pediatric urolithiasis over the last 15 years in terms of technical modifications, surgical outcomes, and complications. The secondary objective was to compare the efficacy and outcomes of standard percutaneous nephrolithotomy (PCNL) and mini-PCNL for renal and upper ureteric calculi.

STUDY DESIGN

Medical records of all patients aged <18 years who presented to the authors' tertiary care hospital in northern India between August 2003 and December 2018 were reviewed retrospectively. Before 2010, all PCNLs performed were standard PCNL, whereas after 2010, most PCNLs performed were mini-PCNL. Thus, the patients were divided into two groups: group A (patients up to 2010) and group B (patients after 2010). These were compared for the type of treatment, success rate, and complications. The outcomes of surgical management of lower ureteric and vesical calculi were also reviewed.

RESULTS

During this period, there were 580 children with urolithiasis (677 stone sites). There were 265 patients (321 stone sites) in group A and 315 patients (356 stone sites) in group B. The median age was seven years (range: 3-18 years). The most common location of calculus was the collecting system of the kidney (n = 398, 58.8%). A total of 175 stone sites (25.8%) were located in the ureter. Urinary bladder calculi were seen in 43 (6.4%) patients. Multiple stones were seen in 61 sites (9.0%). A total of 115 patients in group A underwent standard PCNL, whereas in group B, nine patients underwent standard PCNL and 129 underwent mini-PCNL. Group B had a significantly higher stone clearance rate for mini-PCNL (P < 0.001). Minor complications (grades 1 and 2) accounted for a majority of overall complications in both groups (87.5% in group A and 94.9% in group B).

DISCUSSION

Mini-PCNL is an excellent option for renal calculi in children as it offers dual advantages of improved stone clearance and reduced major complications such as bleeding. Ureteroscopic lithotripsy has been established as the standard for small lower ureteric calculi.

CONCLUSION

For renal and upper ureteric calculi, mini-PCNL has evolved as standard technique with a high stone-free rate and minimum complications compared with standard PCNL. Extracorporeal shockwave lithotripsy and ureteroscopic lithotripsy (URSL)/retrograde intrarenal surgery are acceptable alternatives for smaller stone burden. For lower ureteric and vesical calculi, retrograde approaches such as cystolithotripsy and URSL have now become the standard of care.

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.

Combined Laparoscope and Flexible Ureteroscope Pyelolithotomy Dealing with Large-Burden Complex Renal Calculi in Children Less Than 1 Year Old

Objective: To evaluate the experience and result of combined laparoscope and flexible ureteroscope (f-URS) pyelolithotomy in dealing with large-burden complex renal calculi in children <1 year old. Methods: Eleven patients (7 males and 4 females) <1 year old were retrospectively reviewed between December 2015 and May 2017, who had been diagnosed with renal calculi and received combined laparoscope and f-URS pyelolithotomy. The operations were carried out under general anesthesia. Patient' characteristics, presenting symptoms, operative times, and blood loss, stone-free rate, and postoperative complications were all collected retrospectively. Results: All 11 patients received combined laparoscope and f-URS pyelolithotomy. All operations went smoothly without conversion record and blood transfusion. Average time consumed was 109 minutes (55-187 minutes), and blood loss reported was 16 mL (10-25 mL). Average hospital stay after operation was 7 days (5-11 days). On mean follow-up of 6-12 months, no symptomatic urinary tract infections and urinary calculi were detected. Conclusion: Laparoscope combined f-URS pyelolithotomy is considered safe in the treatment of large-burden multiple renal calculi in infant patients with a high stone clearance rate. It has certain advantages in the treatment of renal calculi in infants <1 year old, and it could be an alternative treatment when other treatments fail or are unavailable.

A new simple scoring system for prediction of success and complication rates in pediatric percutaneous nephrolithotomy: stone-kidney size score

INTRODUCTION

Nomograms and scoring systems designed for predicting the success of percutaneous nephrolithotomy (PCNL) in adults are currently available. However, no scoring system currently exists primarily for predicting PCNL success in children.

OBJECTIVES

The objective of this study was to develop a scoring system to predict the stone-free and complication rates by using pre-operative parameters.

STUDY DESIGN

A retrospective analysis was conducted on data from 434 renal units belonging to patients with kidney stones who underwent PCNL between 1997 and 2017. Renal stone index was calculated by dividing the length of the stone along its longest axis by the length of the kidney along its longest axis. Guy's Stone scores, S.T.O.N.E scores, and CROES scores for adults were calculated by filling in the variables for each patient. Factors that predicted success and complications were examined by univariate and multivariate analyses.

RESULTS

Mean age was 8.3 (1-16) years, and male to female ratio was 236:165. When stone-free patients were compared with other patients, there was a statistically significant difference in the average stone/kidney index (SKI) value (stone size/kidney size on longitudinal axis) (0.266 vs 0.339, P < 0.001). In multivariate analysis, factors that predicted success were the SKI and number of stones. A newly developed scoring scale, the stone-kidney score (SKS), combined scores for both the SKI and the number of stones into one value. A minimum total SKS score was 2, and a maximum total SKS score was 4. Success rates for SKS scores of 2, 3, and 4 were 86.4%, 73%, and 62.9% (P < 0.001), respectively. Complication rates for SKS scores of 2, 3, and 4 were 13%, 22.1%, and 23.8%, respectively.

DISCUSSION

The new scoring system has only two variables (number of stones and SKI) and three risk groups. An SKS score is easier to use and calculate. An SKI value can be simply calculated on any imaging modality by dividing the length of the stone along its longest axis by the length of the kidney along its longest axis. As in the new scoring system, the SKI value combined with the number of stones is useful in predicting stone-free rates after PCNL.

CONCLUSION

When evaluated together, the SKI and presence of multiple stones may predict stone-free rates pre-operatively. The SKS is an individual-specific method that can be easily used in pediatric clinical practice. Further studies are required to develop and standardize this method.

Predictive ability of Guy's stone score in pediatric patients undergoing percutaneous nephrolithotomy

BACKGROUND

Several authors have evaluated, in a number of external validation and predominantly adult studies, Guy's stone score (GSS) as a predictive tool for the assessment of stone clearance after percutaneous nephrolithotomy (PCNL). However, there are limited and conflicting data investigating whether GSS could be a potential independent factor associated with residual stone rates and complications of PCNL for children.

OBJECTIVE

The aim of the current study was to evaluate the ability of GSS, as an independent factor, to predict residual stone rates and complications in pediatric patients undergoing PCNL.

STUDY DESIGN

The records of the pediatric patients who had undergone PCNL for stone disease at the current department were retrospectively reviewed. Variables included patient, stone, and treatment parameters. The GSS was used for assessment of stone complexity. Univariate and multivariate analyses were performed to evaluate factors associated with residual stone rates and complications of pediatric PCNL.

RESULTS

The study group consisted of 114 children (63 boys and 51 girls) with a median (interquartile range) age of 6 (3-11) years and who had undergone 122 PCNLs (eight bilateral). Multivariate logistic regression analysis (Summary Table) demonstrated that the independent risk factors for increased residual stone rate following pediatric PCNL monotherapy were GSS (OR 3.14, 95% CI 1.31-7.49, P = 0.01) and number of calyces involved (OR 4.02, 95% CI 1.11-14.53, P = 0.033). Multivariate logistic regression analysis demonstrated that the independent risk factors for complications following pediatric PCNL were surgical experience (OR 2.72, 95% CI 1.09-6.82, P = 0.032), and operation time (OR 1.01, 95% CI 1.00-1.03, P = 0.040).

DISCUSSION

A prediction model is needed to pre-operatively counsel patients and evaluate outcomes for measuring treatment success of PCNL. The GSS provides a simple, reliable and reproducible tool for describing the complexity of PCNL while predicting postoperative stone-free status, despite its limitations. However, little research has been conducted on the applicability of GSS in pediatric patients undergoing PCNL. In addition, conflicting results have been reported about its association with complications of pediatric PCNL.

CONCLUSIONS

The current study found that although GSS had a significant predictive ability for residual stone rates after pediatric PCNL revealed by multivariate logistic regression, the results did not conclude that complexity of GSS was directly proportional to complications of pediatric PCNL. The factors, including calyceal involvement and surgeon experience, may need to be incorporated in GSS to further improve its ability to predict outcomes of pediatric PCNL.

IRB APPROVED PROTOCOL NUMBER

1422.

Clinical application of super-mini PCNL (SMP) in the treatment of upper urinary tract stones under ultrasound guidance

PURPOSE

To present the safety and efficacy of totally ultrasonography-guided Super-mini percutaneous nephrolithotomy (SMP) in the treatment of upper urinary tract stones both in children and adults.

PATIENTS AND METHODS

We carried out SMP in 104 patients (including 48 children and 56 adults) with upper urinary tract stones between June 2015 and February 2017. All steps of renal access were performed by ultrasonography. The lithotripsy was performed using either Holmium laser or pneumatic lithotripter. Perioperative and postoperative parameters along with operative data were recorded in detail.

RESULTS

The mean age of children and adult patients were 4.4 ± 3.6 and 44.3 ± 15.7 years old, respectively. The stone burden was comparable for both groups (1.72 ± 0.66 vs 1.74 ± 0.56 cm, p = 0.852). Mean operation time was not significant different between two groups (p = 0.052), while the mean haemoglobin drop in children was much lower in adult patients (6.3 ± 6.9 vs 10.9 ± 8.69, p = 0.004). Both groups had similar SFRs in postoperative 1 day and at 1-month follow-up (p = 1.000, p = 0.912). Mean hospital stay of children and adult patients was 2.3 ± 0.8 and 2.2 ± 0.76 days (p = 0.484). The total complication rate was significantly lower in two groups (p = 1.000); none of the patients required blood transfusion.

CONCLUSIONS

Ultrasonography-guided SMP was a safe and effective treatment option for moderate-sized upper urinary tract stones, and has the advantage of preventing radiation hazard, especially for pediatric stone patients.

The role of super-mini percutaneous nephrolithotomy (SMP) in the treatment of symptomatic lower pole renal stones (LPSs) after the failure of shockwave lithotripsy (SWL) or retrograde intrarenal surgery (RIRS)

To assess the safety and efficacy of super-mini percutaneous nephrolithotomy (SMP) in the treatment of symptomatic lower pole renal stones (LPSs) after the failure of shockwave lithotripsy (SWL) or retrograde intrarenal surgery (RIRS), we retrospectively evaluated 44 patients with symptomatic LPSs with previously failed SWL or RIRS and consequently underwent SMP from October 2014 to March 2016. The percutaneous renal access was performed 12-14F with C-arm fluoroscopy or ultrasonographic guidance. Stone disintegration was performed using either Holmium laser or pneumatic lithotripter. Perioperative parameters along with operations were assessed in detail. A total of 44 patients (mean age 49.1 ± 13.7 years) were included in the study. Stone size was 18.4 ± 6.0 mm (range 9-29), operative time was 63.9 ± 32.7 min (range 14-145) and hospital stay was 2.8 ± 1.2 days (range 1-5). The hemoglobin drop was 12.4 ± 8.8 g/L (range 0-31), and no patients required blood transfusion. Complete stone-free status was achieved in 40 (90.9%) patients. Clinically insignificant residual fragments were observed in three (6.8%) patients and only one (2.3%) patient had a 6 mm residual calculus. A total of three minor complications (urinary tract infection, hemorrhage resolved by hemostatics and renal colic requiring analgesics) were observed postoperatively. For symptomatic LPSs after the failure of SWL or RIRS, SMP is a safe and efficient auxiliary option and even might be an alternative to SWL or RIRS, while further considering the stone-free rates and stone-related events.

Stones in pregnancy and pediatrics

Urinary stone disease is a highly prevalent condition affecting approximately 10% of the population, and has increased in incidence significantly over the past 20 years. Along with this, the rate of stone disease among women and children is also on the rise. The management of stone disease in specific populations, such as in children and during pregnancy can present unique challenges to the urologist. In both populations, a multi-disciplinary approach is strongly recommended given the complexities of the patients. Prompt and accurate diagnosis requires a high degree of suspicion and judicious use of diagnostic imaging given the higher risks of radiation exposure. In general, management proceeds from conservative to more invasive approaches and must be individualized to the patient with careful consideration of the potential adverse effects. However, innovations in endourologic equipment and techniques have allowed for the wider application of surgical stone treatment in these patients, and significant advancement in the field. This review covers the history and current advances in the diagnosis and management of stone disease in pregnant and pediatric populations. It is paramount for the urologist to understand the complexities of properly managing stones in these patients in order to maximize treatment efficacy, while minimizing complications and morbidity.

Upper pole access is safe and effective for pediatric percutaneous nephrolithotomy

INTRODUCTION

Upper pole access in percutaneous nephrolithotomy (PCNL) provides a straight tract to the ureter, resulting in easier placement of a guidewire to the ureter, good exposure of the pelvis, calices, and upper ureter, and comfortable manipulations. However, despite these benefits, upper pole access is usually avoided because of the risk of chest complications in both pediatric and adult patients.

OBJECTIVE

We aimed to evaluate the safety and morbidity of single upper pole access in pediatric patients undergoing PCNL.

STUDY DESIGN

We retrospectively reviewed patients aged ≤17 years with renal stones who underwent PCNL with a single access between August 2004 and February 2016. The patients were separated into two groups: the single upper pole access group (SUPAG) and the single other pole access group (SOPAG). We compared the SUPAG and SOPAG in terms of the demographic features of the patients, stone burden and location, operative data, and postoperative outcomes. Complications were classified according to the modified Clavien system.

RESULTS

During the study period, 101 PCNL procedures were performed, 77 of which were managed with only one access. The median age of the 77 patients managed with a single access was 12 years (range 3-17 years). The number of cases in the SUPAG and SOPAG was 10 and 67, respectively. There were no statistically significant differences between the SUPAG and SOPAG in terms of age, sex, stone location, hydronephrosis status, stone area, side of kidney, and previous stone treatment or renal surgery. Furthermoret, there were no significant differences between the groups in terms of the operative parameters. Although the difference was insignificant, the median operation times in the SUPAG and SOPAG were 37 and 45 min, respectively. There was no chest complication or bleeding that required transfusion in the SUPAG. Two cases required transfusion, and one case was managed with a double pigtail catheter (double-J) placement because of prolonged extravasation in the SOPAG. The stone-free ratios were 100% and 82.1% in the SUPAG and SOPAG, respectively.

CONCLUSION

Upper pole access provides similar outcomes to other (middle and lower) pole accesses, and may be performed without serious complications. These results indicate that this is a safe and effective approach of PCNL, and it presents a good alternative for removal of renal stones in pediatric patients.

Ultrasound-guided minimally invasive percutaneous nephrolithotomy in the treatment of pediatric patients <6 years: A single-center 10 years' experience

Owing to the fragile kidney and relative small collecting system of pediatric patients, urologists were always reluctant to treat pediatric urolithiasis with PCNL. Here we conduct a study to assess the effectiveness and safety of pediatric patients with renal calculi <6 years.A total of 88 pediatric patients (99 kidney units) <6 years underwent the ultrasound (US)-guided minimally invasive percutaneous nephrolithotomy in our institute from March 2006 to April 2016. The mean age was 30.9 months (range, 7-72 months). The mean stone size was 19.5 mm (range, 10-50 mm). The group included single stone in 35 kidney units, upper ureteral stone in 12 kidney units, multiple stone in 43 kidney units, and staghorn stone in 9 kidney units. The procedure of puncture and dilation were guided by US solely.The mean operation time was 52.3 minutes (range, 15-140 minutes). The mean postoperative length of stay was 6.0 days (3-16 days). Besides, the initial stone free rate (SFR) was 90.9% (90/99) and the final SFR was 96.0% (95/99). The mean hemoglobin drop was 10.9 g/L (range, 1-25 g/L). Postoperative complications occurred in 12 patients including fever in 11 cases and active pleural effusion in 1 case.The US-guided MPCNL is an effective and safety procedure to treat pediatric patients with stone <6 years.

A comparison of micro-PERC and retrograde intrarenal surgery results in pediatric patients with renal stones

INTRODUCTION

With advancements in endoscopic surgery, open surgical techniques for urinary system stones have paved the way for the application of less invasive treatment modalities in patients with pediatric kidney stone disease. These treatment options include extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery (RIRS).

OBJECTIVE

We aimed to compare the efficacy and safety of RIRS and micro-PCNL techniques in the surgical treatment of kidney stones in pediatric patients.

STUDY DESIGN

A total of 48 pediatric patients, who underwent RIRS or micro-PERC for pediatric kidney stone disease, were retrospectively analyzed. Urinalysis, urine culture, serum creatinine (Cr), blood urea nitrogen (BUN), calcium, phosphorus, parathyroid hormone, 24-hour urine sample, complete blood count (CBC), urinary system X-ray, kidney ureter bladder (KUB), and urinary system ultrasonography (USG) test results were evaluated prior to the procedure. Intravenous pyelography (IVP), non-contrast computed tomography (CT), and renal scintigraphy evaluations were also performed, if necessary. The patients were divided into two groups: micro-PERC group (n = 25) and RIRS group (n = 23). Data relating to the duration of the operation, duration of fluoroscopy, length of hospitalization, complication rates, and stone-free rates were recorded.

RESULTS

The mean ages of the micro-PERC and RIRS groups were 4 ± 2.3 and 10.9 ± 3 years, respectively (p = 0.001). However, the mean stone sizes were 12.2 ± 2.8 and 13.7 ± 3.5 mm, respectively (p > 0.05). The mean duration of operation was 75.1 ± 18.9 min in the micro-PERC group and 62.3 ± 15.3 min in the RIRS group (p > 0.05). In addition, the mean duration of fluoroscopy was 115 ± 35.4 s in the micro-PERC group and 39.9 ± 15.3 s in the RIRS group. The stone-free rates in the micro-PERC and RIRS groups following the procedure were reported to be 84% (21/25) and 82.6% (19/23), respectively (p > 0.05). In terms of the degree of preoperative hydronephrosis between the groups, the rates of mild and moderate-severe disease were 76% (19 out of 25) and 24% (6 out of 25), and 69.5% (16 out of 23) and 30.4% (7 out of 23) in the micro-PERC and RIRS groups, respectively.

CONCLUSION

In recent years, technological developments in minimally invasive procedures, such as micro-PERC and RIRS, have facilitated choices made by urologists in the effective and safe first-line treatment in pediatric patients.

Predictive factors of bleeding among pediatric patients undergoing percutaneous nephrolithotomy

The purpose of this study is to determine the perioperative risk factors for increased blood loss in children undergoing percutaneous nephrolithotomy (PCNL).We retrospectively reviewed the data on pediatric patients who had undergone PCNL for stone disease in our department. Blood loss estimation was quantified by measuring the changes in hematocrit plus the volume of red blood cells transfused. Univariate and multivariate linear regression analyses were performed to evaluate risk factors associated with increased blood loss after pediatric PCNL. Variables included patient, stone, and treatment parameters. The study group consisted of 105 renal units in 97 children with a median (interquartile range) age of 5 (3-9) years. On univariate linear regression analysis female gender (p = 0.030), absence of hydronephrosis (p = 0.013), increasing stone burden (p = 0.002), staghorn stone type (p = 0.013), multi-tract access (p < 0.001), and prolonged operative time (p < 0.001) were significantly associated with increased blood loss after pediatric PCNL. However, multivariate linear regression analysis demonstrated that the only independent risk factors for increased blood loss following pediatric PCNL were degree of hydronephrosis (B -1.329, 95% CI -2.451 to -0.208, p = 0.021), number of tracts (B 2.545, 95% CI 0.221-4.869, p = 0.032), and operative time (B 0.031, 95% CI 0.008-0.053, p = 0.007). Identifying pediatric patients at increased risk of bleeding following PCNL is crucial to minimize morbidity and hospital stay, and thus, the cost of treatment. Our study demonstrated that degree of hydronephrosis, number of tracts and operative time are important factors in reducing blood loss during pediatric PCNL.

Percutaneous nephrolithotomy: technique

Percutaneous nephrolithotomy (PCNL) is considered to be the first line of treatment for large renal stones. Though PCNL comes with higher morbidity, its efficacy is unbeaten by other minimally invasive modalities. However, potential complications, such as bleeding, occur. Improved skills and modifications of the procedure may reduce the probability of adverse outcomes. This article discusses the current trends and standards in PCNL technique with special focus on all important steps as positioning, access, instruments, dilation, disintegration, and exit, including outcomes, complication management, and training modalities.

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.

Efficacy and safety of percutaneous nephrolithotomy with adult standard size instruments in children under 3 years of age: a 10 years single-center experience

BACKGROUND

Using percutaneous nephrolitotomy (PCNL) with large adult instruments in treatment of pediatricurolithiasis is still in debate. This study was conducted to evaluate the efficacy and safety of PCNL with adult's instrument in treatment of patients less than 3 years old.

METHODS

Data on patient characteristics and outcomes for 261 consecutive children undergoing PCNL at a Labbafinejad University Hospital were collected prospectively from September 2006 to February 2016. Thirty-two children, with 34 renal units, who were treated with PCNL were enrolled in the study. All PCNL procedures were performed via subcostal approach with one access tract in all of them. Postoperative complications were evaluated according to the modified Clavien grading system.

RESULTS

The mean age of patients was 19.4 ± 6.2 months. Two patients had bilateral stones; thus, PCNL was performed on 34 kidney units. The mean size of the largest stone diameter was 17.5 ± 7.8 mm. The mean duration of procedures was 121.52 ± 29.05 minutes, ranging from 60 to 180 minutes. The most common complication was fever (n = 9, 26.4%), and hemorrhage that needs transfusion was the second one (n = 4, 11.7%). Seventeen patients with complications were in the first degree of Clavien complication system and five of them were in the second degree.

CONCLUSIONS

Due to our experience, utilizing PCNL with adult-sized instruments in management of urolithiasis in less than 3 years old children appeared to be effective and relatively safe.

Mini-percutaneous nephrolithotomy with high-power holmium YAG laser in pediatric patients with staghorn and complex calculi

INTRODUCTION

Shock wave lithotripsy (SWL) is the treatment of choice for most cases of renal lithiasis in children. Some cases, however, are refractory to SWL and may be associated with anatomic and metabolic changes or a large stone burden. In these circumstances, mini-percutaneous nephrolithotomy (mini-PCNL) is an option.

OBJECTIVE

The aim was to assess the safety and efficacy of high-power holmium YAG (Ho:YAG) laser in mini-PCNL for staghorn calculi.

PATIENTS AND METHODS

The clinical records relating to 35 mini-PCNLs (Table) performed between January 2008 and December 2012 in 33 patients (27 boys and 6 girls; mean age 7 years, range 2-18 years) were retrospectively reviewed. Twenty-two (66.7%) of the patients had undergone a previous SWL (28.6% three sessions). The mini-PCNL puncture technique used involved fluoroscopic guidance with the C arm at 0-90° in the supine position. An 18F tract was used. Stone fragmentation was performed with a high-power Ho:YAG laser (Lumenis 100 W).

RESULTS

Ten of the mini-PCNLs (28.6%) were right sided, and 25 were left sided (71.4%). Stones were located in the lower calyceal group in 64% of patients and in the renal pelvis in 50%. The mean stone size was 4.46 cm(2) (range 3-13.20 cm(2)). The number of stones varied between one and 20, and 83.3% were radiopaque. The laser was set at 70 W (range 50-100 W) (3.5 J/pulse with a frequency of 20 pulses/s). The mean surgical time was 150 min. In 78% of patients, complete stone clearance was achieved, and the overall stone-free rate rose to 85% when residual stones were treated with either SWL or retrograde intrarenal surgery. No perioperative complications were seen.

DISCUSSION

There are few reports in the literature concerning the use of a high-power laser for treatment of complex stones and the few that do exist relate to adults have similar results, showing it to be highly effective and safe, with low morbidity. Some limitations of the present study must be acknowledged. It was retrospective and a relatively small number of patients were included. However, randomized prospective studies are required to confirm our findings and conclusions.

CONCLUSION

In the pediatric population, mini-PCNL with high-power Ho:YAG laser is feasible and safe and represents the technique of choice for complex renal stones.

Lower calyceal and renal pelvic stones in preschool children: A comparative study of mini-percutaneous nephrolithotomy versus extracorporeal shockwave lithotripsy

OBJECTIVES

To compare outcomes of the mini-percutaneous nephrolithotripsy technique and extracorporeal shockwave lithotripsy for lower calyceal and renal pelvic stones in preschool children.

METHODS

From January 2010 to December 2014, single renal pelvic or lower calyceal calculi 10-25 mm in size in children (age ≤6 years) treated by either extracorporeal shockwave lithotripsy (64 patients) or the mini-percutaneous nephrolithotripsy technique (54 patients) were included. Extracorporeal shockwave lithotripsy was carried out by using a Dornier electromagnetic lithotripter. The mini-percutaneous nephrolithotripsy technique was through 14-Fr renal access using a 9.5-Fr semirigid ureteroscope with holmium:yttrium aluminium garnet lithotripsy. The two study groups were compared using Mann-Whitney, χ(2) -test or Fisher's exact test.

RESULTS

Stone parameters were similar in the mini-percutaneous nephrolithotripsy technique and extracorporeal shockwave lithotripsy groups in all patients, and in the pelvic (39 Miniperc, 52 extracorporeal shockwave lithotripsy) and lower calyceal (15 Miniperc, 12 extracorporeal shockwave lithotripsy) subgroups. Stone-free rates in the mini-percutaneous nephrolithotripsy technique and extracorporeal shockwave lithotripsy groups were 88.9% versus 43.8% (P < 0.001) and 94.4% versus 81.2% (P = 0.032) after first and last sessions, respectively. In the renal pelvis, they were 87.2% versus 50% (P < 0.001) and 94.9% versus 84.6% (P = 0.179), whereas in the lower calyx, they were 93.3% versus 16.7% (P < 0.001) and 93.3% versus 66.7% (P = 0.139) after first and last sessions, respectively. Retreatment rates in the mini-percutaneous nephrolithotripsy technique versus extracorporeal shockwave lithotripsy were 7.4% versus 50% (P < 0.001), 7.7% versus 46.2% (P < 0.001), and 6.7% versus 66.7% (P = 0.003) in all patients, renal pelvic and lower calyceal stones, respectively. No significant difference was found in complications (P = 0.521). Auxiliary procedures were required in 9.4% and 1.9% of children in the extracorporeal shockwave lithotripsy and mini-percutaneous nephrolithotripsy technique groups, respectively.

CONCLUSIONS

The mini-percutaneous nephrolithotripsy technique has significantly higher stone-free rates than extracorporeal shockwave lithotripsy for renal pelvic and lower calyceal stones (10-25 mm), with a lower retreatment rate and without a significant increase in complications.

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.

Do Outcomes of Percutaneous Nephrolithotomy in Horseshoe Kidney in Children Differ from Adults? A Single-Center Experience

OBJECTIVE

To compare the efficacy, outcome, and safety of percutaneous nephrolithotomy (PCNL) for stones in horseshoe kidney (HSK) in children compared with adults.

METHODS

We retrospectively reviewed data of 18 renal units in children (<15 years) and 26 renal units in adult patients with HSKs who underwent PCNL between March 2008 and June 2015.

RESULTS

Mean age of the study group was 25.92 ± 15.79 with adults having 36.12 ± 11.84 (range 20-65) and children having 10.32 ± 2.88 (range 5-15). Mean stone burden was 311.20 ± 203.99 (104-1080 mm(2)) with children of 211.13 ± 130.21 (104-500 mm(2)) and adults of 382.68 ± 219.27 (114-1080 mm(2)). Success rate is defined as either complete stone free or with asymptomatic and clinical insignificant residuals fragment of <3 mm on postoperative imaging. Initial success rate was 79.54% (86.61% in adults vs 72.22% in children). After auxiliary procedure, the final success rate is 93.18% (adults: 92.30% vs children: 94.44%). Overall complications noted in 12 cases with 23.07% in adults and 33.33% in children, most of them were minor complications.

DISCUSSION

There was no significant difference in initial and final success rate. Complication is slightly higher in children although statistically not significant. The outcomes and complications are similar to those reported in other studies of pediatric PCNL.

CONCLUSIONS

Outcomes in child and adult HSKs do not differ significantly with respect to success rate and complications. Children have a relatively smaller stone burden compared with adults with a similar distribution. We found that most of the puncture can be made infracostal in children as well as adults.

Metal telescopic and Amplatz sheath dilation in nephrolithotomy

INTRODUCTION

Comparison of Amplatz sheath percutaneous nephrolithotomy (Amplatz PCNL) and metal telescopic dilation PCNL (MTD PCNL) with respect to clinical outcomes and complications.

MATERIALS AND METHODS

Single-institution retrospective chart review with 73 patients who underwent PCNL divided into two groups: Amplatz PCNL (n = 26) and MTD PCNL (n = 47). Efficacy (stone-free rate, residual stones, and surgical duration) and safety (transfusion rate and hemoglobin decrease) were evaluated. Complications were recorded and classified using the modified Clavien classification system.

RESULTS

The two PCNL groups were similar regarding mean age, stone burden, side, stone location, and stone composition. There were no significant differences in surgery duration (101 ± 28 vs. 98 ± 30 min; P = 0.906), transfusion rate (3.9% vs. 4.3%; P = 0.382), and hemoglobin drop (0.9 ± 0.9 vs. 1 ± 0.7 g/dl; P = 0.424) for Amplatz and MTD PCNL, respectively. Stone-free rate (86% vs. 68%; P = 0.001) was significantly higher while residual fragments rate (37% vs. 60%; P = 0.001) was significantly lower in Amplatz PCNL compared to MTD PCNL. However, tube stay time (4.4 ± 1.8 vs. 5.8 ± 3.6 days; P = 0.005) and hospital time (8.6 ± 2.6 vs. 9.7 ± 5.5 days; P = 0.0001) were significantly longer in Amplatz PCNL compared to MTD PCNL. Clavien grading revealed a significantly higher rate of low-grade complications (I-III) for the MTD PCNL in comparison to Amplatz PCNL (10.6% vs. 3.9%, respectively; P = 0.011). There were no major complications and no tract dilation failure.

CONCLUSION

The study demonstrates that Amplatz PCNL is a safe and effective procedure to remove large renal stones compared with MTD PCNL.

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.

Tracking of radiation exposure in pediatric stone patients: The time is now

BACKGROUND

Despite the increasing incidence of pediatric nephrolithiasis, there is little data quantifying the radiation exposure associated with treatment of this disease. In this study, pediatric patients with nephrolithiasis who were managed at a single institution were identified, and the average fluoroscopy time and estimated radiation exposure associated with their procedures were reported.

METHODS

Stone procedures performed on pediatric patients between 2005 and 2012 were retrospectively identified. Procedures were classified as primary ureteroscopy (URS), stent placement prior to ureteroscopy (SURS), percutaneous nephrolithotomy (PCNL), and bilateral ureteroscopy (BLURS). Patient demographic information, stone size, stone location, number of radiographic images, and fluoroscopy times were analyzed.

RESULTS

A total of 152 stone procedures were included in the final analysis (92 URS, 38 SURS, eight BLURS and 14 PCNL). Mean patient age at time of stone treatment was 15.94 ± 4.1 years. Median fluoroscopy times were 1.6 (IQR 0.8-2.4), 2.1 (IQR 1.6-3.0), 2.5 (IQR 2.0-2.9), and 11.7 (IQR 5.0-18.5) minutes for URS, SURS, BLURS and PCNL, respectively. There was a moderate correlation between stone size and fluoroscopy time (r = 0.33). When compared with ureteroscopic procedures, PCNL was associated with a significantly higher fluoroscopy time (11.7 vs 2.1 min, P < 0.001). The estimated median effective dose was 3 mSv for ureteroscopic procedures and 16.8 mSv for PCNL. In addition to radiation exposure during treatment, patients in this cohort were exposed to an average of one (IQR1-3) CT scan and three (IQR 1-8) abdominal X-rays. No new malignancies were identified during the limited follow-up period.

CONCLUSIONS

Radiation exposure during treatment of pediatric stone disease is not trivial, and is significantly greater when PCNL is performed. Given the recommended maximum effective dose of 50 mSv in any one year, urologists should closely monitor the amount of fluoroscopy used, and consider the potential for radiation exposure when choosing the operative approach. Prospective studies are currently underway to elucidate precise dose measurements and localize sites of radiation exposure in children during stone treatment.