Percutaneous nephrolithotomy in infants: evaluation of a single-center experience. Urology. 2012;80:408-411. [PMID: 22743259 DOI: 10.1016/j.urology.2012.04.058]

Feasibility, efficacy, and safety of retrograde intrarenal surgery in <1-year age group: A single-center experience

Purpose

Urolithiasis in infants is uncommon. Percutaneous nephrolithotomy, extracorporeal shockwave lithotripsy, and retrograde intrarenal surgery (RIRS) are the management options. RIRS is the least studied of these options in infants. In our series of 23 cases, we aim to assess the feasibility, efficacy, and safety of RIRS in <1-year age group.

Materials and Methods

This was a retrospective analysis of a series of 23 infants who underwent RIRS in our hospital from January 2018 to March 2021. Children who were <12 months of age and had the largest stone size of <20 mm were included in the study.

Results

Twenty-three patients (male - 15; female - 8) were included in the study. The mean age was 10 ± 2.31 months (range, 4-12 months). The mean stone size was 11.6 ± 2.96 mm (range, 7.5-19 mm). The mean operative time was 29.44 ± 7.45 min (range, 17-42 min). Six patients (22.2%) had mild hematuria (Clavien I), and seven patients (25.9%) had postoperative fever. Stone size had a significant positive correlation with laser time, operative time, and intraoperative intravasation, but no significant association with stone-free rate. At 2-month follow-up, 4 (three patients) out of 27 renal units had residual stones (stone-free rate [SFR] - 85.1%). No patient had long-term complications like urethral or ureteric stricture or stone recurrence during the given follow-up period.

Conclusion

RIRS is a feasible and minimally invasive treatment for renal stones in infants with acceptable SFRs.

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.

Is supine a preferred position for percutaneous nephrolithotomy in the pediatric age group? A randomized controlled study

BACKGROUND

The aim is to evaluate supine versus prone position in mini-percutaneous nephrolithotomy in pediatric renal urolithiasis management.

METHODS

A randomized controlled trial was constructed to evaluate supine versus prone position in pediatric PCNL. Seventy pediatric patients with a stone burden ≥1.5 cm were randomized into two groups.

RESULTS

Sixty-three patients were available for evaluation in our study with no significant difference in the perioperative demographic data. The supine group showed a shorter operation time of 43.9 min compared to 73.5 min in the prone group. The stone-free rate was higher in the supine group, with a 93.9% SFR compared to 83.3% in the prone group. The supine group showed a shorter hospital stay of 2.0±1.0 days, compared to 3.20±1.56 days in the prone group. No significant difference was seen in the perioperative complication rate and fluoroscopy time between both groups.

CONCLUSIONS

Supine mini-percutaneous nephrolithotomy is safe and effective in managing pediatric renal stones, with a higher stone-free rate, less operative time, and less hospital stay compared to the prone position.

Management of Pediatric Urolithiasis in an Italian Tertiary Referral Center: A Retrospective Analysis

Background and Objectives: In recent years, the prevalence of pediatric urolithiasis has increased in North America and Western countries, though it is endemic in developing countries. The aim of this study is to describe the experience of a tertiary pediatric referral center in the surgical management of pediatric urolithiasis. Materials and Methods: We retrospectively reviewed the experience of patients ≤ 16 years old affected by urinary stones who underwent surgery. Results: From April 2021 to September 2023, 31 pediatric patients underwent surgical procedures for stone diseases at our department: 13 preschool-aged (1-5 years) and 18 school-aged (6-16 years) children. During this period, 12 URSs, 17 RIRSs, and 2 PCNLs were recorded. Five patients had residual fragments at first, so three of them underwent a second endourological lithotripsy (2 RIRSs and 1 URS). Complete clearance was finally achieved in 27 patients. The stone composition was evaluated in 25 cases. Conclusions: Numerous innovations in the surgical treatment of pediatric urolithiasis have resulted from the development of smaller devices and new technology. Our results show how, in experienced centers, retrograde and percutaneous lithotripsy are safe and effective procedures for use in pediatric populations.

Pediatric Mini-Percutaneous Nephrolithotomy Using Self-Retained Screwed Amplatz Sheath vs Ordinary Sheath

Objective: To evaluate the use of a new 16F mini-screwed sheath in pediatrics in comparison to a 16F ordinary Amplatz sheath. Methods: Sixty-seven patients <18 years with renal calculi between 1 and 2 cm who was a candidate for mini-percutaneous nephrolithotomy (mini-perc) between January 2019 and September 2021 were randomized by closed envelope in group A (34 patients) using new mini-screwed sheath and group B (33 patients) with ordinary mini-sheath. Patients with contraindications for percutaneous nephrolithotomy were excluded. Results: No significant difference was present between both groups according to patients and stone demographics. There was no significant difference between both groups regarding puncture site and number. The mean operative time was 51.25 ± 2.15 minutes and 52.35 ± 3.45 minutes in groups A and B, respectively. The fluoroscopy time was significantly lower in group A (2.1 ± 0.85 minutes) than in group B (2.9 ± 1.05 minutes). Tract loss was 18.2% in group B while 0% in group A. Although bleeding was less in group A, it was nonsignificant. The stone-free rate was (94.11%) and (90.9%) in group A and group B, respectively. Conclusion: Screwed sheath enables the urologist to have a stable track during pediatric mini-perc surgery despite the thin abdominal wall in the pediatric. The screw sheath provides significantly lower fluoroscopy time and decreases the need for nephrostomy tube insertion when compared with ordinary sheath in mini-perc renal surgery.

Guideline Adherence of Paediatric Urolithiasis: An EAU Members' Survey and Expert Panel Roundtable Discussion

Background: Paediatric nephrolithiasis has increased globally, requiring standardized recommendations. This study aims to assess the paediatric urolithiasis care between EAU members along with the statements of three experts in this field. Methods: The results of an electronic survey among EAU members comparing the guideline recommendations to their current practice managing paediatric nephrolithiasis in 74 centres are contrasted with insights from an expert-panel. The survey consisted of 20 questions in four main sections: demographics, instrument availability, surgical preferences and follow-up preferences. Experts were asked to give insights on the same topics. Results: A total of 74 responses were received. Computerised Tomography was predominantly used as the main imaging modality over ultrasound. Lack of gonadal protection during operations was identified as an issue. Adult instruments were used frequently instead of paediatric instruments. Stone and metabolic analysis were performed by 83% and 63% of the respondents respectively. Conclusions: Percutaneous Nephrolithotomy is the recommended standard treatment for stones > 20 mm, 12% of respondents were still performing shockwave lithotripsy despite PNL, mini and micro-PNL being available. Children have a high risk for recurrence yet stone and metabolic analysis was not performed in all patients. Expert recommendations may guide clinicians towards best practice.

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.

Comparison of Efficiency and Safety of Retrograde Intrarenal Surgery and Micropercutaneous Nephrolithotomy in Pediatric Kidney Stones Smaller than 2 cm: A Prospective Cohort Study

Objective: To compare the safety and efficacy of two minimally invasive surgical techniques used for pediatric stone disease: retrograde intrarenal surgery (RIRS) and micropercutaneous nephrolithotomy (micro-PCNL). Materials and Methods: A prospective study was designed to include children aged <15 years with a single stone <20 mm. Sixty-four patients were assigned to undergo either an RIRS or a micro-PCNL (1:1 ratio). Demographic parameters, stone size, location, operative data, complications, stone-free status, and efficacy quotient were compared. Results: Due to anatomic considerations, seven patients were shifted to the micro-PCNL arm, thus resulting in 39 micro-PCNLs performed vs 25 RIRS in the end. Because of the deviation from planned surgery that was significantly higher in the RIRS group (p = 0.011), the analysis was done in a prospective cohort comparison. Stone-free rates were similar for micro-PCNL and RIRS groups (80% vs 82.2%). The operative (median 60 vs 90 minutes, p < 0.001), fluoroscopy (median 15 vs 30 seconds, p = 0.004), and lithotripsy times (median 15 vs 25 minutes, p = 0.007) were shorter in the RIRS group. However, despite the larger stone size, the efficiency quotient was significantly higher in the micro-PCNL group (82.1% vs 54.1%; p = 0.009). None of the patients experienced significant hematuria requiring blood transfusion, as well as no ureteral orifice obstructive complication was detected within the follow-up period. Conclusion: RIRS and micro-PCNL techniques in children have similar stone-free and complication rates. The operative, fluoroscopy, and lithotripsy times were shorter, deviation from the planned surgery, and the number of sessions under anesthesia was higher in the RIRS group. Despite the larger stone size, efficacy quotient was significantly higher in the micro-PCNL group.

Imaging modalities and treatment of paediatric upper tract urolithiasis: A systematic review and update on behalf of the EAU urolithiasis guidelines panel

BACKGROUND

Prompt diagnosis and treatment of paediatric urolithiasis are required to avoid long term sequelae of renal damage.

OBJECTIVE

To systematically review the literature regarding the diagnostic imaging modalities and treatment approaches for paediatric urolithiasis.

STUDY DESIGN

PubMed, Science Direct, Scopus and Web of Science were systematically searched from January 1980-January 2019. 76 full-text articles were included.

RESULTS

Ultrasound and Kidney-Ureter-Bladder radiography are the baseline diagnostic examinations. Non-contrast Computed Tomography (CT) is the second line choice with high sensitivity (97-100%) and specificity (96-100%). Magnetic Resonance Urography accounts only for 2% of pediatric stone imaging studies. Expectant management for single, asymptomatic lower pole renal stones is an acceptable initial approach, especially in patients with non-struvite, non-cystine stones<7 mm. Limited studies exist on medical expulsive therapy as off-label treatment. Extracorporeal shock wave lithotripsy (SWL) is the first-line treatment with overall stone free rates (SFRs) of 70-90%, retreatment rates 4-50% and complication rates up to 15%. Semi-rigid ureteroscopy is effective with SFRs of 81-98%, re-treatment rates of 6.3-10% and complication rates of 1.9-23%. Flexible ureteroscopy has shown SFRs of 76-100%, retreatment rates of 0-19% and complication rates of 0-28%. SFRs after first and second-look percutaneous nephrolithotomy (PNL) are 70.1-97.3% and 84.6-97.5%, respectively with an overall complication rate of 20%. Open surgery is seldom used, while laparoscopy is effective for stones refractory to SWL and PNL. Limited data exist for robot-assisted management.

CONCLUSIONS

In the initial assessment of paediatric urolithiasis, US is recommended as first imaging modality, while non-contrast CT is the second option. SWL is recommended as first line treatment for renal stones <20 mm and for ureteral stones<10 mm. Ureteroscopy is a feasible alternative both for ureteral stones not amenable to SWL as well as for renal stones <20 mm (using flexible). PNL is recommended for renal stones >20 mm.

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.

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.

Flexible ureteroscopic lithotripsy for the treatment of upper urinary tract calculi in infants

We evaluated the clinical value of flexible ureteroscopic lithotripsy for the treatment of upper urinary tract calculi in infants. Fifty-five infants with upper urinary tract calculi were included in this study: 41 males and 14 females. Retrograde intrarenal surgery was performed by an 8 Fr/30 cm flexible ureterorenoscope (POLY®) combined with a holmium laser. CT scanning or radiography of the kidneys, ureters, and bladder region was performed one month after the operation to confirm the clearance of calculi. All the 55 infants with calculi in 74 sides underwent 66 flexible ureteroscopic lithotripsy procedures. The median operation time was 30 min. The median amount of flushing fluid was 500 mL. The stone-free rate after a single session treatment was 94.6%, within which 10 infants underwent simultaneous bilateral flexible ureteroscopy lithotripsy. Catheters were retained in 45 infants for 24-48 h after the operation. Continuous high fever due to reflux was present in two cases. Flushing fluid extravasation was found in one infant. Some patients with minor complications, such as mild hematuria, irritation symptoms, and low fever, recovered without treatment. The duration of hospitalization time after the operation was approximately 1-5 days. Flexible ureteroscopic lithotripsy is a safe, highly efficient, minimally invasive, and reproducible operation for removal of upper urinary tract calculi in infants. This technique is a convenient method for postoperative management of patients that enhances their rapid recovery. It is a promising option for therapy of infants ineffectively treated by extracorporeal shockwave lithotripsy.

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.

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.

Ultra-mini-percutaneous nephrolithotomy in pediatric nephrolithiasis: both low pressure and high efficiency

INTRODUCTION

The management of urolithiasis in children differs from adults because of anatomic and metabolic abnormalities. At present, various minimally invasive and invasive treatment strategies have been recommended to treat urinary tract Stones, including shock wave lithotripsy (SWL), standard percutaneous nephrolithotomy (PNL), mini-PNL, retrograde intrarenal surgery (RIRS), micro-PNL, and a new technique termed ultra-mini PNL (UMP). UMP is a new method for the treatment of kidney stones. The main difference between UMP and standard PNL or mini-PNL lies in the small access sheath and in its design. A 9.5F pediatric compact cystoscope was used (Figure). A major advantage of UMP is that it provides similar stone-free rates when compared with standard PNL, with lower intrarenal pressure than micro-PNL.

OBJECTIVE

The aim of the study was to determine the applicability and safety of UMP in the treatment of pediatric kidney stones.

PATIENTS AND METHODS

We retrospectively reviewed the files of 39 kidney stones in children who had undergone UMP between May 2011 and October 2014. The indications for UMP included stones resistant to SWL, stones requiring repeated sessions of SWL, and stones size larger than 20 mm.

RESULTS

The study included 17 females and 22 males, with a mean age of 5.8 ± 4.6 years. The mean hemoglobin loss was 0.9 ± 0.6 mg/dL and none of the patients required a blood transfusion. The complication rate of the PNL procedure was 15.3% (n = 6). Complete clearance was achieved in 32 patients (82%) with UMP monotherapy, which increased to 34% (87.1%) 4 weeks after the operation.

DISCUSSION

Management of urolithiasis necessitates a balance between stone clearance and morbidity related to the procedure. SWL often leads to persistent residual stones. The developing RIRS can minimize the risks associated with bleeding and visceral injury, but sometimes the abnormal pelvicaliceal anatomy and poor imaging of the flexible ureteroscopy may impact its success rate and applications. It has been reported that PNL can be performed safely and effectively to achieve a higher stone-free rate; however, it has serious complications such as bleeding that requires blood transfusion in 11-14% of the cases with increased risk of kidney loss. The recent development of smaller sheaths allows tract formation with minimal damage to the renal parenchyma, thereby reducing procedure-related morbidity without diminishing its therapeutic efficacy.

CONCLUSION

The most important advantage of this surgical technique that has been developed is similar stone-free rates to standard PNL and lower intrarenal pressure than micro-PNL. Our experience supports that UMP is safe and effective for the management of renal stones in children.

Ultrasound-guided mini-percutaneous nephrolithotomy in patients aged less than 3 years: the largest reported single-center experience in China

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.

Outcomes following 'mini' percutaneous nephrolithotomy for renal calculi in children. A single-centre study

INTRODUCTION

This retrospective review was undertaken to identify the postoperative outcomes of children undergoing 'mini' percutaneous nephrolithotomy (MPCNL) at a single institution.

OBJECTIVE

Outcomes measured included: percentage of stone clearance, postoperative analgesia requirements, the need for intraoperative or postoperative blood transfusion, length of stay and morbidity.

STUDY DESIGN

A total of 46 patients were reviewed over a two-and-a-half-year period; the mean age was 7.3 years (range: 1-16 years). The MPCNL was performed with a radiological-guided peripheral puncture, followed by dilatation of the nephrostomy tract to a maximum Amplatz sheath size of 16-French; an 11-French nephroscope was used. Stone disintegration was achieved either with pneumatic or laser lithotripsy.

RESULTS

Complete stone clearance was achieved in 35/46 children (76%). The remaining 11 children had a stone clearance rate of over 80%. No patients required intraoperative/postoperative blood transfusion. A total of 39% of patients were managed on simple/non-opiate based analgesia, with 54% requiring opioid analgesia postoperatively for less than 24 h. There were no procedure-related complications and no mortalities. The mean length of stay was 2.24 days.

DISCUSSION

The management of urolithiasis can be challenging in children. The use of percutaneous nephrolithotomy, is becoming increasingly popular in the treatment of paediatric urolithiasis. The stone clearance rate in children undergoing standard PCNL, has been reported to be 50-98% in the literature [1,2,3,4]. Samad et al. [2] in 2006, reported their experience in 188 consecutive PCNLs, using a 17Fr or 26Fr nephroscope. Their largest sub group included children aged >5-16 yrs. Within this group, 57% were treated with a 17Fr nephroscope and 43% with the 26Fr nephroscope, achieving stone clearance of only 47% with PCNL monotherapy. In this group the transfusion rate was 3% [2]. Badawy et al., reported their experience of 60 children in 1999, using a 26 or 28Fr Amplatz sheath. They reported an 83.3% stone clearance with single session PCNL, with only one procedure being abandoned due to intraoperative bleeding requiring blood transfusion [3]. In 2007, Bilen et al. reported their experience and compared the use of 26Fr, 20Fr and 14Fr (mini) PCNL. Stone size, previous surgery and the mean haemoglobin drop postoperatively did not change between the groups, however the blood transfusion rate was higher in the 26Fr and 20Fr Amplatz sheath groups. The stone clearance was highest in the 'mini PCNL' group at 90%, compared to 69.5% in the 26Fr and 80% in the 20Fr group [4]. MPCNL has become increasingly popular over recent years, with stone clearance reported as 80-85% [5-7] following a single session of MPCNL as monotherapy. In 2012, Yan et al. reported 85.2% stone clearance with mini PCNL monotherapy (tract size 14-16Fr), with no children requiring blood transfusion [6]. Zeng et al. reported their experience of 331 renal units in children, with stone clearance rates reaching 80.4% and a blood transfusion rate of 3.1% [8]. In our centre, we do not perform postoperative haemoglobin levels as a matter of routine and any investigations are performed on an intention to treat principle. Bilen et al. reported no blood transfusions being required in their cohort of patients undergoing MPCNL [4] and this is supported by Yan et al. [6].

CONCLUSION

Mini PCNL is an effective and safe procedure for the treatment of paediatric renal stones. In the present series, all children achieved greater than 80% stone clearance, none received a blood transfusion (intra/postoperatively) and there were no mortalities. Postoperative pain was managed with simple analgesia in 39%; however, the majority required opiate analgesia for less than 24 hours.

Flank-free Modified Supine Percutaneous Nephrolithotomy in Pediatric Age Group

OBJECTIVE

To evaluate the safety and efficacy of pediatric percutaneous nephrolithotomy (PCNL) in the flank-free modified supine position (FFMSP). PCNL in the supine position is increasingly and successfully used in pediatric age group. Different modifications of supine positions have been described; however, the best supine position is not well established and remains a matter of debate.

PATIENTS AND METHODS

This prospective study included 22 children presenting with single renal pelvis stone (2-3 cm) in the period between May 2012 and April 2014. Diagnosis was set by plain x-ray and computed tomography in all patients. PCNL was performed with the patients placed in the FFMSP. The operative time and hospital stay were estimated. The outcome and any perioperative complications or conflicts were recorded.

RESULTS

The study included 22 children (15 boys and 7 girls) with a solitary renal pelvis stone. Mean ± standard deviation age of the patients was 9.5 ± 3.2 years (range, 3-15.5 years). Stone length, operative time, and hospital stay had mean ± standard deviation of 2.4 ± 0.23 cm, 65.1 ± 18.7 minutes, and 4.4 ± 0.9 days. Stone-free rate was 90.9% after 1 session of PCNL. One patient (4.5%) needed a second-look PCNL. Shock wave lithotripsy was performed for another patient. Postoperative fever occurred in 4 patients (18.2%). One patient received postoperative blood transfusion. Postoperative transient urinoma occurred in 2 patients (9.1%).

CONCLUSION

PCNL in pediatric age group via FFMSP was proved to be safe and effective in management of renal pelvis stones of size 2-3 cm. It provides stone clearance rate comparable with that reported of conventional PCNL in the prone position.

Minipercutaneous nephrolithotomy in infants: a single-center experience in an endemic region in Turkey

The objective of the study is to evaluate the effectiveness and safety of miniaturized percutaneous nephrolithotomy (mini-PNL) method in infantile patients <3 years of age diagnosed with renal stones. We studied 48 renal units in 40 patients of infantile patients <3 years of age who underwent mini-PCNL at our institute. The mean age of the patients was 24.02 (5-36) months. The mean diameter of the stones was 22.3 mm (11-45 mm). Intrarenal access was achieved under fluoroscopic (n = 43) or ultrasonographic (n = 5) guidance under general anesthesia. A 20 Fr peel-away sheath, a 17 Fr rigid nephroscope and a pneumatic intracorporeal lithotripsy were used. Mean operative time for PNL was 85 (25-135) min. Mean fluoroscopy time was estimated as 3.7 min. The mean hospital stay was 4.3 days (2-10). Mean hemoglobin loss was 0.89 g/L (11.56-10.67) and three of the patients, including one case during the perioperative period, required blood transfusions. Colonic perforation developed in one case. In two patients, urinary drainage persisted for more than 24 h after withdrawal of the nephrostomy tube. Seven patients developed urinary tract infections (UTI). At the end of the postoperative first week, the stone-free rate was estimated to be 81.2 %. In conclusion, for percutaneous management of renal stones in the infantile age group, mini-PNL is an applicable treatment modality that can be applied through small incisions. It has higher stone-free rates, shorter hospital stays, and excellent esthetic outcomes. In this age group especially, surgical exposure to hypothermia and radiation should be avoided.

Minimally invasive percutaneous nephrolithotomy in children less than three years of age: five-year experience in 234 cases

OBJECTIVE

The treatment of infant renal stones is still a huge challenge to the urologist. The present study aimed to evaluate the safety and efficiency of the minimally invasive percutaneous nephrolithotomy (MPCNL) method as a treatment for infant renal stones, and also to analyze the specific techniques and related complications of the procedure.

PATIENTS AND METHODS

From January 2008 to December 2012, 234 cases (72 girls and 162 boys, mean age 15.8 months, range 5-36 months) aged under 3 years and treated with MPCNL for renal stones were analyzed retrospectively. 125 cases were younger than 12 months, 67 cases were between 13 and 24 months and 42 cases between 25 and 36 months. The indications for MPCNL were (1) stone over 1 cm(2), (2) hydronephrosis and (3) recurrent urinary tract infection. An initial percutaneous access to the targeted renal calyx was obtained through an ultrasound-guided peripheral calyceal puncture. Stones were fragmented by a holmium laser with a pediatric nephroscope via 14-F tract.

RESULTS

All the procedures were performed by single tract, and totally 247 tracts were established, including 245 14-F tracts, 1 16-F tract and 1 12-F tract, respectively. The stones were located in the left kidney (n = 91), right kidney (n = 105) and in both kidneys (n = 28), respectively. Regarding the puncture point, in 228 cases it was in the 12th subcostal space and in 19 cases in the 11th intercostal space. The distribution of target puncture calyx and the subsequent residual calculi were as follows: 39 cases in the upper calyx with 2 cases of stone residual, 148 in the middle calyx with 3 stone residuals, and 60 in the lower calyx with 2 stone residuals, respectively. As a result, completely stone-free state was achieved in 240 kidney units (97.2%). The mean operating time was 32.5 min. None of the patients required blood transfusion and no septic shock occurred after operation. A large quantity of washing fluid was infiltrated into the abdominal cavity in 3 cases.

CONCLUSION

Using a single tract ≤14 F, MPCNL is a safe and effective procedure in the management of renal stones in infant less than 3 years old.

Comparison of children versus adults undergoing mini-percutaneous nephrolithotomy: large-scale analysis of a single institution

Objective

As almost any version of percutaneous nephrolithotomy (PCNL) was safely and efficiently applied for adults as well as children without age being a limiting risk factor, the aim of the study was to compare the different characteristics as well as the efficacy, outcome, and safety of the pediatric and adult patients who had undergone mini-PCNL (MPCNL) in a single institution.

Methods

We retrospective reviewed 331 renal units in children and 8537 renal units in adults that had undergone MPCNL for upper urinary tract stones between the years of 2000–2012. The safety, efficacy, and outcome were analyzed and compared.

Results

The children had a smaller stone size (2.3 vs. 3.1 cm) but had smilar stone distribution (number and locations). The children required fewer percutaneous accesses, smaller nephrostomy tract, shorter operative time and less hemoglobin drop. The children also had higher initial stone free rate (SFR) (80.4% vs. 78.6%) after single session of MPCNL (p<0.05); but no difference was noted in the final SFR (94.7% vs. 93.5%) after auxiliary procedures. The complication rate (15.6% vs. 16.3%) and blood transfusion rate (3.1% vs. 2.9%) were similar in both group (p>0.05). Both groups had low rate of high grade Clavien complications. There was no grade III, IV, V complications and no angiographic embolization required in pediatric group. One important caveat, children who required multiple percutaneous nephrostomy tracts had significant higher transfusion rate than in adults (18.8% vs. 4.5%, p = 0.007).

Conclusions

This contemporary largest-scale analysis confirms that the stone-free rate in pediatric patients is at least as good as in adults without an increase of complication rates. However, multiple percutaneous nephrostomy tracts should be practiced with caution in children.