Critical Prospective Appraisal of Renal Morphology and Function in Children Undergoing Shockwave Lithotripsy and Percutaneous Nephrolithotomy

Single step track dilatation for percutaneous nephrolithotomy in children

Introduction and objectives

Data on the use of single step dilatation technique during pediatric percutaneous nephrolithotomy (PCNL) in the literature is sparse. In this prospective randomized study, we aimed to compare the safety, efficacy, and perioperative complications of single step versus serial tract dilatation using Alken metal telescopic dilators during pediatric PCNL.

Methods

Patients undergoing PCNL were randomized into two groups according to the dilatation technique used. In group A, Alken telescopic serial metal dilatation was utilized, and in group B, single step dilatation was performed. Inclusion criteria included children < 18 years with stone burden from 2 to 4 cm, located in the renal pelvis ± one calyx, who were candidates for PCNL.

The primary outcomes were access time and complications’ rate. The secondary outcomes were dilatation fluoroscopy time, operative duration, stone free rate, postoperative hospital stay, hemoglobin deficit, and need for blood transfusion. Both outcomes were evaluated and compared between both treatment groups.

Results

A total of 70 patients were randomized into group A (35 patients) and group B (35 patients). Access was successfully obtained in all procedures. All the procedures were performed through a single tract.

Access time and dilatation fluoroscopy time were shorter in group B (statistically significant). Patients in group A had higher rate of complications (statistically significant). Intraoperative bleeding requiring blood transfusion was less in single track dilatation than serial metal track dilatation.

Conclusions

Compared to serial metal track dilatation, single step dilatation showed comparable operative time and stone free rate, with significantly reduced access time and dilatation fluoroscopy time.

Is Mini Percutaneous Nephrolithotomy a Game Changer for the Treatment of Renal Stones in Children?

Background

Mini percutaneous nephrolithotomy (MPCNL) is a newer surgical procedure that has changed the management of paediatric renal stones.

Objective

To evaluate MPCNL morbidity and success rates for renal stones as a function of patient age in a paediatric cohort.

Design, setting, and participants

This was a retrospective case series that included 143 consecutive patients younger than 17 yr who underwent MPCNL at our institution between January 2016 and November 2020. The patients were categorised into three different age groups: <6 yr (n = 71, 49.7%), 6–11 yr (n = 44, 30.8%), and 12–17 yr (n = 28, 19.6%). MPCNL was performed in all patients through 16–20Fr tracts.

Outcome measurements and statistical analysis

The stone-free rate, perioperative complications, tract number, operative time, postoperative haemoglobin change, and hospitalisation time were evaluated for each age group.

Results and limitations

MPCNL was performed in 143 paediatric patients (88 boys and 55 girls; mean age 6.53 yr). The mean stone burden (± standard deviation) was 2.096 ± 1.01 cm in group one, 2.05 ± 1.05 cm in group two, and 3.46 ± 19.94 cm in group three; group three was significantly larger (p = 0.001). After a single MPCNL session, 92.42% of patients experienced complete stone clearance. All age groups were similar in terms of stone-free rate (p = 0.82), hospitalisation time (p = 0.94), postoperative haemoglobin change (p = 0.06), and perioperative complications (p = 0.62). However, stone size (p = 0.009), stone complexity (p = 0.001), number of access points (p = 0.03), and operative time (p = 0.009) were higher in the group aged 12–17 yr.

Conclusions

MPCNL is an effective and safe procedure in younger as well as older children. Age should not be considered a limiting factor for MPCNL in children, and MPCNL should be considered the primary option for treating paediatric renal stones when PCNL is indicated.

Patient summary

Our results show that surgical removal of kidney stones through an incision in the skin and using miniaturised instruments is an effective and safe procedure for children.

Safety and efficacy of minimally invasive percutaneous nephrolithotomy for infantile nephrolithiasis. Single centre experience from Pakistan

OBJECTIVE

To assess the efficacy and safety of mini-percutaneous nephrolithotomy (PCNL) for small renal stones 1-2 cm in size in infants less than one year.

MATERIAL AND METHODS

This descriptive case series was conducted in the department of pediatric urology Institute of Kidney Diseases Peshawar, Pakistan, from March 2019 to March 2022. All the patients underwent mini-PCNL in prone position under GA with 14 Fr access sheath and 10 Fr nephroscope. Stone clearance was assessed by non-contrast CT KUB at 30th postoperative day. Patients with no residual fragments on the non-contrast CT KUB were defined as stone-free. Patients with residual fragments of any size were defined as procedure failure. Safety was determined in terms of intra and postoperative complications.

RESULTS

A total of 51 infants were included in the study. The mean age of patients was 9.6 + 1.8 (5-12 month). The mean stone size was 15.8 + 2.7 (10-21) mm in length and 12.3 + 2.2 (8-17) mm in width. PCNL mean operative time was 51.6 ± 7.1 (40-70) minutes. Complete stone clearance at one month was observed in 46 (90.2%) patients. Residual fragments were seen in 5(9.8%) patients with a mean size of 1.6 + 0.4 (0.9-2.0) mm. None of the patients required any additional procedure for clearance of stones. In 7 (13.7%) patients, some post-operative complications were observe, all were grade I complications, including fever in 5(9.8%) and transient hematuria in 2(3.9%) patients.

CONCLUSION

Mini-PCNL is a safe and effective treatment for renal stones in infants measuring 1-2 cm with high SFR and an acceptable complication rate.

Punctures versus shocks: a comparison of renal functional and structural changes after percutaneous nephrolithotomy and shockwave lithotripsy for solitary renal stone

Objective:

To evaluate renal functional and structural changes following percutaneous nephrolithotomy and shockwave lithotripsy for solitary non-obstructing non-staghorn renal stone.

Materials and methods:

Patients with solitary unilateral non-staghorn renal stones who were planned for percutaneous nephrolithotomy (20 patients) and shockwave lithotripsy (20 patients) were prospectively evaluated for renal functional and structural changes 60 days after the procedure and complete clearance of stones. Tc99-dimercaptosuccinic acid was used to assess cortical scarring and Tc99-diethylenetriamine pentaacetic acid and Tc99-levo levo ethylecysteine were used for glomerular filtration rate calculations, respectively.

Results:

The mean stone size was 24.4 mm and 13.7 mm in the percutaneous nephrolithotomy group and the shockwave lithotripsy group, respectively. No new cortical scars developed in either of the groups on Tc99-dimercaptosuccinic acid scan. Both the treated and untreated kidneys showed an overall insignificant fall in glomerular filtration rate in both the groups. The number of patients showing significant deterioration in the individual glomerular filtration rate in both the treated and untreated renal unit was more in the shockwave lithotripsy group.

Conclusion:

Both percutaneous nephrolithotomy and shockwave lithotripsy are comparable in terms of adverse effects on renal parenchyma and renal function.

Level of evidence:

Not applicable for this multicentre audit.

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.

Which is the best treatment of pediatric upper urinary tract stones among extracorporeal shockwave lithotripsy, percutaneous nephrolithotomy and retrograde intrarenal surgery: a systematic review

Background

Although the indications of minimally invasive treatments for pediatric urolithiasis are similar to those in adults, it is still crucial to make the right treatment decision due to the special considerations of children. This review aims to evaluate the efficacy and safety of extracorporeal shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery (RIRS) in the management of pediatric upper urinary tract stones.

Methods

EMBASE, PubMed, and the Cochrane Library were searched from their first available date to March 2018. The studies that meet the inclusive criteria were included. The efficacy and safety of the treatments were assessed by means of meta-analysis of the stone free rate (SFR), complication rate, effectiveness quotient (EQ) and secondary outcome indicators.

Results

A total of 13 comparative studies were identified for data analysis. PCNL presented a significantly higher SFR compared with SWL. Similarly, the single-session SFR of RIRS was significantly higher than SWL. However, no significant difference was found between RIRS and SWL in the overall SFR. There was no significant difference between PCNL and RIRS in the SFR. Furthermore, no significant differences in complication rates were found among the three therapies. Compared with the other two treatments, PCNL had a longer operative time, fluoroscopy time and hospital stay. SWL had a shorter hospital stay, higher retreatment rate and auxiliary rate in comparison with the other two treatments. The present data also showed that PCNL presented a higher EQ than the other two treatments, and RIRS had a lower efficiency than SWL and PCNL. In the subgroup analysis of pediatric patients with stone ≤20 mm, the comparative results were similar to those described above, except for the higher complication rate of PCNL than SWL.

Conclusions

Although SWL as an outpatient procedure provides shorter hospital stay and reduces operative time, it has a lower SFR and higher retreatment rate than the other two treatments. PCNL exhibits a higher SFR and EQ than SWL; nevertheless, it has a longer operative time and fluoroscopy time than the other two procedures. RIRS offers a similar SFR as PCNL but a lower efficiency than PCNL.

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.

Impact of repeated extracorporeal shock wave lithotripsy on prepubertal rat kidney

This study aimed to investigate the effects of repeated extracorporeal shock wave lithotripsy (ESWL) on the kidneys of prepubertal and adult rats. Thirty rats were used: 15 were prepubertal (3 weeks of age) with an average body weight of 72.3 ± 3.3 g, and 15 were adults with of 265 ± 11.3 g. The prepubertal and adult rats were separately and randomly allocated to three groups, each consisting of five rats. Following anesthetization, the left kidney of each rat in each group received shock waves in one, two, or three sessions separated by 72 h. The rats in each group were killed 72 h after the last ESWL session, and both kidneys were harvested; the right kidney was used as the control. Renal injury was examined with histological analysis, immunohistochemistry, and Western blot to detecting the expression of heat-shock protein-70, tumor necrosis factor-alpha-α, intercellular adhesion molecule-1, and monocyte chemoattractant protein-1 as markers of renal damage. All of these markers were similarly increased with increased ESWL sessions in both age groups. Histological analysis revealed more serious fibrosis and inflammation in the ESWL-treated kidneys in both groups than in the controls, with the damage increasing with increasing numbers of sessions. ESWL on the kidney increased renal damage according to the number of sessions in both age groups of rats, and the effects of ESWL on renal injury were similar in the two groups. However, there were generally no significant differences in the effects of ESWL on molecular indicators of renal injury between prepubertal and adult rats.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of tubeless percutaneous nephrolithotomy on early renal function: Does it deteriorate?

BACKGROUND

The impact of standard percutaneous nephrolithotomy (PCNL) on short or long-term renal function has been evaluated in many studies. We evaluated the effect of tubeless PCNL on early renal function.

MATERIALS AND METHODS

A total of 117 patients referring to our university center for PCNL were enrolled in the study if they were matched with the inclusion criteria. Serum creatinine and hemoglobin (Hb) levels were measured before PCNL and 6, 24, 48, and 72 h after the operation. Glomerular filtration rate (GFR) was calculated using Cockroft-Gault formula.

RESULTS

There were 79 (67.5%) men and 38 women (32.5%) with the mean age of 49.94 years ranging from 18 to 80 years in the study group. The mean creatinine level elevated in the first 48 h after PCNL but it started to reduce on the 3(rd) day (mean preoperative creatinine level: 1.32 ± 0.18 mg/dL, mean creatinine level after 48 h: 1.59 ± 0.24 mg/dL, creatinine level after 72 h: 1.42 ± 0.21245 mg/dL) (P < 0.0001). GFR values had the same rise and fall pattern as serum creatinine level (mean preoperative GFR: 74.89 mL/min, mean GFR after 48 h: 64.04 mL/min, GFR after 72 h: 69.54 mL/min, P < 0.0001). PCNL also affected blood Hb level. The mean preoperative Hb level was 15.06 ± 0.87 g/dL and it significantly decreased to 13.09 ± 1.06 g/dL after the operation (P < 0.0005).

CONCLUSIONS

Tubeless PCNL like standard PCNL decreases GFR in the very early postoperative days. It is recommended that factors that might have a negative impact on renal function during first few days after PCNL be avoided.

Effect of percutaneous nephrolithotomy on renal functions in children: assessment by quantitative SPECT of (99m)Tc-DMSA uptake by the kidneys

OBJECTIVE

To determine the impact of percutaneous nephrolithotomy (PNL) on global and regional renal function in children.

METHODS

In total, 40 children (41 renal units) undergoing PNL were included in this prospective study. All patients were evaluated using quantitative single-photon emission computed tomography (QSPECT) with technetium-99 m-dimercaptosuccinic acid ((99m)Tc-DMSA) examinations before and 3 months after surgery.

RESULTS

The mean age was 9.5 years (range, 3-16), and the mean stone size was 3.4 cm (range, 2-6.5). Of the cases, 39 (95%) were managed as being stone-free after a single session of PNL. After additional treatment procedures, 40 (97.5%) of the cases were managed as being stone-free. Of the 41 renal units, new focal cortical defects on (99m)Tc-DMSA scans were seen in 4 (9.7%) patients. Total relative uptake in the treated kidneys increased from 42.3% to 44.1%. The mean creatinine level before PNL was 1.18 ± 0.45 (0.8-1.6) mg/dL compared with 1.16 (0.7-1.5) mg/dL by the end of the follow-up period (not statistically significantly different, p > 0.05).

CONCLUSIONS

PNL in children is a safe and feasible method for the maximal clearance of stones. QSPECT of (99m)Tc-DMSA confirmed that renal function is preserved or even improved after percutaneous stone removal.

Percutaneous nephrolithotomy: Effect of unilateral procedure on contralateral kidney function

BACKGROUND

Although long-term effects of percutaneous nephrolithotomy (PCNL) on renal function and structure have been evaluated, knowledge regarding the immediate effects of surgery on renal function is limited. We conducted this study to evaluate the impact of unilateral PCNL on bilateral renal function during immediate post-operative period.

MATERIALS AND METHODS

From April to September 2012, 40 eligible patients were enrolled in this study and underwent unilateral PCNL. During the post-operative period, creatinine clearances (CrCl) of treated and untreated sides were estimated separately and pattern of changes in bilateral renal function following this procedure was evaluated.

RESULTS

Following the operation, CrCl of both kidneys showed a similar pattern of changes, of course more dramatic on treated side. We observed progressive decline in CrCl of both sides followed by bilateral improvement in renal function toward pre-operative values.

CONCLUSIONS

During the early post-operative period following unilateral PCNL, both kidneys experienced a temporary drop in function warranting more intensive post-operative care.

Management of obstructive calcular anuria with acute renal failure in children less than 4 years in age: a protocol for initial urinary drainage in relation to planned definitive stone management

OBJECTIVES

To describe and evaluate our protocol for management of children≤4years old with obstructive calcular anuria (OCA) and acute renal failure (ARF) to improve selection of initial urinary drainage (ID) method and to facilitate subsequent definitive stone management (DSM) as studies discussing this special group of patients are still few.

PATIENTS AND METHODS

Patients with a contraindication to any method of ID were excluded. Decision (percutaneous nephrostomy (PCN) or double J (JJ) stent) was based on degree of hydronephrosis and planned DSM. We used 4.8-5Fr JJ or 6-8Fr PCN under general anesthesia and fluoroscopic guidance. According to our protocol, JJ is inserted for hydronephrosis≤grade 1. When the hydronephrosis is >grade 1, patients with radiolucent stones were treated by JJ whatever the site of the stone. When the stones were radiopaque, PCN was reserved for stones in a solitary functioning kidney and bilateral ureteric stones prepared for subsequent bilateral ureterolithotomy (or stone prepared for ureterolithotomy in a solitary kidney). After normalization of renal functions, DSM was staged attacking only one side before discharge. Both sides were cleared at the same session in cases with bilateral ureterolithotomy. Renal or ureteric stones suitable for SWL in a solitary kidney were treated with percutaneous nephrolithotripsy (PNL) or ureteroscopy. This was followed also in patients with bilateral stones suitable for SWL by clearing one side using ureteroscopy or PNL before discharge. Open surgery (OS) was reserved for cases with failed ureteroscopy or PNL, for ureteric stones>2.5 cm in size or very large volume complex renal stones. Stone free rate (SFR) was evaluated by CT. Our protocol was evaluated as regard recovery of renal functions, complications, and number of interventions to clear stones.

RESULTS

This study included 62 boys and 22 girls presented with anuria for 1-4 days. JJ and PCN were inserted in 105 and 30 ureterorenal units (URU), respectively. Creatinine returns normal within 72 h. JJ insertion formed a part of DSM in 78/159 (49%) URU (stones prepared for extracorporeal shockwave lithotripsy or oral chemolytic dissolution therapy). PCN was the ideal tract for subsequent PNL in 11/159 (6.9%) URU. Accordingly, ID participated by 55.97% in DSM. Both operative and imaging times were slightly longer with PCN than JJ. There was no statistically significant difference in the insertion success or mean period to return to normal chemistry. Complications of both methods were mild and without any significant difference. Endourologic procedures constituted the majority of our interventions. Open surgical and endoscopic interventions for clearance of stones (including ID, treatment conversion and 2ry procedures) were done once for 25 patients, twice for 43 patients while it was needed three times for 16 patients. Total number of interventions was 149 procedures. SFR was 94%.

CONCLUSION

Our protocol ensures adequate ID with minimal complications when using our selection criteria in children≤4 years in age with OCA and ARF. It also minimizes number of subsequent procedures to clear stones. Complications and success in insertion and drainage were equivalent in PCN and JJ groups.

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

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

Minimally invasive percutaneous nephrolithotomy 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.

Minimally invasive approaches and their efficacy in pediatric urolithiasis

OBJECTIVE

We compared the frequency of usage and success of minimally invasive approaches in the management of pediatric urolithiasis in our clinic.

MATERIAL AND METHODS

Data from pediatric patients (≤16 years of age) who had undergone percutaneous nephrolithotomy (PNL), ureterorenoscopy (URS), and extracorporeal shock wave lithotripsy (ESWL) between January 2001 and December 2011 were retrospectively investigated.

RESULTS

In this study, 415 pediatric patients, who were treated for 291 renal, and 124 ureteral stones, were evaluated. The patients were treated with PNL (n=148; 82 boys, 66 girls), URS (n=99; 58 boys, and 41 girls) or ESWL (n=168; 91 boys, and 77 girls). The mean patient ages were 7.3 (1-16), 9.1 (1-16), and 8.8 (1-16) years in the PNL, URS, and ESWL groups, respectively. The stone-free rates after treatment with PNL, URS, and ESWL were 77, 83.8 and 88.7%, respectively.

CONCLUSION

It is important that selected therapies are properly planned, and the use of minimally invasive approaches is important in pediatric patients due to potentially high recurrence rates. Currently, ESWL, PNL and URS are performed with high success rates for the treatment of stones, and open surgery is rarely used due to the success obtained with minimally invasive approaches.

Does child's age affect interval to stone-free status after SWL? A critical analysis

OBJECTIVE

To evaluate the success rates and complications of extracorporeal shock wave lithotripsy (ESWL) in children with renal stones in an age-dependent manner.

METHODS

From 2006 to 2010, 164 children (male/female ratio 1:3) with renal calculi have been treated with ESWL (PiezoLith3000 lithotripter). The children were divided into 2 age groups: group 1, 0-6 years old (n = 133); and group 2, 7-15 years (n = 31). The patient- and treatment-related parameters were recorded for comparative evaluation. The success of ESWL in terms of the stone-free rates, additional procedures, and complications were comparatively evaluated. The data were analyzed statistically.

RESULTS

The mean age of groups 1 and 2 was 28 ± 18 months (range 4-71) and 119 ± 28 months (range 73-178), respectively. Although general anesthesia was used for all patients in group 1, 29% of the patients were treated under neuroleptic anesthesia in group 2. During the 3-month follow-up period, the complete stone-free rate was 94.7% (126 of 133), and treatment was unsuccessful in 7 patients (5.3%) in group 1. The corresponding data were 87% (27 of 31; P = .222) and 4 (13%; P = .089) in group 2. The stone-free rate after the first session was 67.6% (90 of 133) and 38.7% (12 of 31) in groups 1 and 2, respectively (P = .004). The mean number of ESWL sessions applied was 1.6 (range 1-5) and 2.9 (range 1-6) in groups 1 and group 2, respectively (P = .0001). No major complications were noted.

CONCLUSION

Our results have demonstrated that ESWL is highly successful in the management of renal calculi in children. Compared the outcomes by age, the younger children become stone free more quickly than the older children with fewer ESWL sessions.

SWL in lower calyceal calculi: evaluation of the treatment results in children and adults

OBJECTIVE

To evaluate the treatment parameters of shockwave lithotripsy (SWL) in lower calyceal calculi in adults and children in a comparative manner.

MATERIAL AND METHODS

Between 2006 and 2011, SWL was performed for lower calyceal calculi in 282 adults (mean age 48.5 years, range 28-64) and 54 children (mean age 48 months, range 5-141). The Wolf Piezolith 3000 lithotriptor has been used for SWL. Success rates, auxiliary procedures, additional interventions, and complications were evaluated in detail in a comparative manner.

RESULTS

Mean stone size was 7.7 mm (range 5-25) and 8.1 mm (range 5-23) in children and in adults, respectively. Mean SWL sessions were 1.5 (range 1-5) in children and 2.4 (range 1-6) in adults. Although 66.6% of children were stone-free after the first session, 28% of adult patients were stone-free after the first SWL session, showing a statistically significant difference (P = .0001). After the treatments, although a complete stone-free status was obtained in 85% of children, 31.5% of adults were stone-free at 3-month follow-up after SWL (P = .0001). Although no auxiliary procedures were needed in children, 8.2% of adults required them. Likewise, the percentage of additional procedures were higher in adults than children (20.2%).

CONCLUSION

SWL for lower calyceal calculi has been found to be highly successful in pediatric patients. These results demonstrate that, irrespective of stone size, SWL should be the first treatment alternative in the management of lower calyx stones in children.

Pediatric extracorporeal shock wave lithotripsy: Predicting successful outcomes

Extracorporeal shock wave lithotripsy (ESWL) is currently a first-line procedure of most upper urinary tract stones <2 cm of size because of established success rates, its minimal invasiveness and long-term safety with minimal complications. Given that alternative surgical and endourological options exist for the management of stone disease and that ESWL failure often results in the need for repeat ESWL or secondary procedures, it is highly desirable to identify variables predicting successful outcomes of ESWL in the pediatric population. Despite numerous reports and growing experience, few prospective studies and guidelines for pediatric ESWL have been completed. Variation in the methods by which study parameters are measured and reported can make it difficult to compare individual studies or make definitive recommendations. There is ongoing work and a need for continuing improvement of imaging protocols in children with renal colic, with a current focus on minimizing exposure to ionizing radiation, perhaps utilizing advancements in ultrasound and magnetic resonance imaging. This report provides a review of the current literature evaluating the patient attributes and stone factors that may be predictive of successful ESWL outcomes along with reviewing the role of pre-operative imaging and considerations for patient safety.

Endoscopic stone management in children

PURPOSE OF REVIEW

The management of urolithiasis in children has significantly changed over the past 20 years. Extracorporeal shockwave lithotripsy (SWL) was initially the preferred modality of treatment. More recently, ureteroscopy and percutaneous nephrolithotomy (PCNL) are being used at an increasing frequency in the management of pediatric stone disease.

RECENT FINDINGS

Development has been made in various aspects of pediatric endoscopic stone management. Ureteroscopy and PCNL have been applied at an increasing frequency to treat pediatric stone disease, which has guided modifications to improve the procedures. Increased endoscopic experience with managing urolithiasis has broadened the indications wherein these methods are utilized. Technology is continually advancing to meet the needs of this population. Ureteroscopes have been modified to accommodate the pediatric ureter, optics advanced, and access sheaths are used to improve results. In addition, technique is constantly being refined.

SUMMARY

Further experience will direct surgeons as to when ureteroscopy and PCNL are appropriate. The incidence of urolithiasis is on the rise in developing nations; there is a need to address the most efficient method of treatment that minimizes the morbidity to the child.

Clinical practice: surgical approaches to urolithiasis in children

The incidence of urolithiasis in children is increasing. Adequate knowledge of treatment modalities and surgical options is therefore essential for every pediatrician. Surgical approaches to urolithiasis in children continue to evolve with advancements in technology and sophistication of current equipment and techniques. Perhaps the most significant development in new techniques is the advent of robotic-assisted laparoscopy. This review, for the general pediatrician, summarizes the most recent pediatric data and guidelines for surgical approaches to treatment of urolithiasis.

Effect of percutaneous nephrolithotomy and tract dilatation methods on renal function: assessment by quantitative single-photon emission computed tomography of technetium-99m-dimercaptosuccinic acid uptake by the kidneys

OBJECTIVES

The aim of this study was to determine the impact of percutaneous nephrolithotomy (PCNL) and tract dilatation methods on global and regional renal function using quantitative single-photon emission computed tomography (QSPECT) of technetium-99m-dimercaptosuccinic acid ((99m)Tc-DMSA).

METHODS

Seventy-five patients undergoing PCNL between May 2008 and April 2009 were included in this randomized study. Of the 75 patients, 50 were evaluated by QSPECT of (99m)Tc-DMSA examinations before and at 3 to 6 months after surgery. This group of patients were categorized into three groups according to the dilatation technique used: group I (balloon dilator, n = 12 [24%] patients), group II (metal dilator, n = 14 [28%] patients), and group III (Amplatz dilator, n = 24 [48%] patients).

RESULTS

Of 50 renal units, new focal cortical defects on (99m)Tc-DMSA scan were seen in nine patients (18%). In six of these kidneys the site of focal defect corresponded to the access site for tract formation during PCNL (two in group II and four in group III). Total relative uptake and total area of treated kidney, for the entire group, increased from 42.2% and 42.3% preoperatively to 44.12% and 43.9% postoperatively. There was no statistically significant differences between the groups for total uptake and area of the treated kidneys before and after the procedure (p > 0.05 for each parameter).

CONCLUSIONS

QSPECT of (99m)Tc-DMSA confirms that renal function is preserved or often improved after percutaneous stone removal, and nephrostomy tract dilatation methods have similar effects on renal function.

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

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

[Extracorporeal lithotripsy in children - the efficacy and long-term evaluation of renal parenchyma damage by DMSA-99mTc scintigraphy]

PURPOSE

To determine the effectiveness of extracorporeal shock-wave lithotripsy (ESWL) and possible deleterious effects on renal parenchyma of children subjected to treatment of renal lithiasis, using renal scintigraphy with 99mTc dimercapto-succunic acid (DMSA).

PATIENTS AND METHODS

From January 2004 to November 2007, 18 children (age 3-10 years) underwent ESWL (Philips-Dornier) for kidney urolithiasis. All patients underwent preoperative evaluation, including physical examination, urine culture, image exams and renal scintigraphy with Tc99-DMSA. Evaluation after treatment consisted of a clinical examination, blood pressure measurement, urine culture, renal ultrasound and Tc99-DMSA, repeated at 3, 6 and 12 months, which were compared to the scans obtained before ESWL to determine possible morphological or functional changes.

RESULTS

Success in the stones fragmentation was achieved in all cases - in 9 patients (50%) with one session of ESWL, in 6 (33%) with two sessions and in 3 patients (17%) with 3 sessions of ESWL. Only one patient (5%), after three sessions of ESWL and 6 months of follow-up showed change in size of right kidney with a decrease in tubular function, without hypertension or other major changes. In the other cases, there was absence of hypertension up to 12 months of follow-up, absence of renal hematomas detected by ultrasound or significant renal scars in scintigraphic examinations.

CONCLUSION

ESWL is effective and safe for treating renal lithiasis in children. Renal parenchyma lesions may occur early after treatment, but these lesions are transients and resolve spontaneously in virtually all cases; generally, there are no irreversible renal lesions associated with ESWL, even after the follow-up period with clinical examination, ultrasound examination and 99mTc-DMSA scintigraphy.

Contemporary surgical management of pediatric urolithiasis

With miniaturization of instruments and refinement of surgical technique, the management of pediatric stone disease has undergone a dramatic evolution. While shock wave lithotripsy (SWL) is still commonly used to treat upper tract calculi, the use of ureteroscopy (URS) has dramatically increased and is now the procedure of choice for upper tract stone burdens less than 1.5cm at centers with significant experience. Percutaneous nephrolithotomy (PCNL) has replaced open surgical techniques for the treatment of large stone burdens greater than 2cm, with efficacy and complication rates similar to the adult population. Large institutional series demonstrate comparable stone-free and complication rates with SWL, URS, and PCNL, but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burdens are needed to reach consensus regarding the most effective primary treatment modality in children.

Time-course for recovery of renal function after unilateral (single-tract) percutaneous access in the pig

INTRODUCTION

The immediate (1-5 hours) response to percutaneous renal access (PERC) in pigs is vasoconstriction in the treated kidney. The present study determined the longer-term (72 hours) consequences of this surgical procedure.

MATERIALS AND METHODS

Adult female pigs were anesthetized, and bilateral glomerular filtration rate (GFR), effective renal plasma flow (ERPF), urine flow rate, and sodium excretion rate were measured before and 1 hour after sham PERC or unilateral, single-tract PERC using a balloon dilator system. Animals were allowed to regain consciousness and were then anesthetized 72 hours later for final measurements of bilateral renal hemodynamic and excretory function together with renal para-aminohippuric acid (PAH) extraction (a measure of tubular organic anion transport efficiency).

RESULTS

Bilateral renal hemodynamics were unchanged in the sham-PERC-treated pigs over the 72-hour observation period. In contrast, both GFR and ERPF were reduced by approximately 55% in the PERC-treated kidney within 1 hour of access, and returned to pre-PERC levels within 72 hours. Renal hemodynamics were not significantly altered in the opposite, untreated kidney of the PERC-treated pigs. Renal PAH extraction was decreased in PERC-treated kidneys at 72 hours post-PERC. Both sham-PERC-treated and PERC-treated animals showed similar falls in urine flow rate and sodium excretion rate immediately after treatment and at 72 hours after PERC.

CONCLUSIONS

Renal vasoconstriction characterized the acute response of the treated kidney to unilateral PERC, whereas impaired tubular function (reduced PAH extraction) with near-normal GFR and ERPF characterizes the later (72 hours) response to PERC.

Extracorporeal shock wave lithotripsy in prepubertal children: 22-year experience at a single institution with a single lithotriptor

PURPOSE

The sophistication of percutaneous nephrolithotomy and ureteroscopy challenges the efficacy of ESWL for urolithiasis in prepubertal patients. We evaluated our long-term experience with ESWL in these patients and determined its efficiency.

MATERIALS AND METHODS

We retrospectively reviewed the charts of all prepubertal patients who underwent ESWL. We evaluated the need for tubing, the 3-month stone-free rate, the need for additional ESWL, and the effect of stone size and location, and cystinuria on the 3-month stone-free rate.

RESULTS

Between 1986 and 2008, 119 males and 97 females with a mean age of 6.6 years who had urolithiasis underwent ESWL using the Dornier HM3 lithotriptor. We treated 157 children with renal calculi with an average +/- SD diameter of 14.9 +/- 8.9 mm, of whom 66 (42%) required a tube in the urinary system. The 3-month stone-free rate was 80% and 31 patients (19.7%) needed an additional procedure. Stone location did not affect the stone-free rate but stone size did. We treated 59 patients for ureteral stones with an average stone length of 9.5 +/- 4.8 mm, of whom 41 (69%) required tube insertion. The 3-month stone-free rate was 78% and 13 patients (22%) needed an additional procedure. The 3-month stone-free rate did not depend on stone location or size. The rate was 37.5% in patients with cystinuria and 82.5% in all others (p <0.0001). Six patients (2.8%) had complications.

CONCLUSIONS

The 3-month stone-free rate after ESWL in prepubertal patients is 80% and 20% of patients require additional procedures. ESWL is most effective for kidney stones less than 11 mm. ESWL has inferior results for cystine stones compared to other calculi. Complications are rare.

Pediatric urolithiasis

PURPOSE OF REVIEW

We review the recent literature on pediatric urolithiasis and present up-to-date findings on epidemiology, diagnosis, and medical and surgical management.

RECENT FINDINGS

There are surprisingly few reliable data on pediatric urolithiasis incidence, but widespread anecdotal and single-center reports suggest that more children with stones are being seen. The contamination of Chinese infant formula with melamine caused urolithiasis and other renal problems in hundreds of thousands of infants in the region, underlining the role of environmental factors in urolithiasis. Efforts continue to determine normal metabolic parameters in children, but have been hampered by variations among regions, races, and ethnicities. The Bonn Risk Index may prove to be a useful tool for assessing risk of urolithiasis in children. Children with recurrent urolithiasis are more likely to have detectable metabolic abnormalities. Surgical approaches to urolithiasis in children continue to evolve, with robotic-assisted laparoscopy being perhaps the most significant new technique. Finally, clinicians and radiologists must be aware of the potential for dextranomer/hyaluronic acid (Deflux) implants to mimic distal ureteral stones on computed tomography (CT) scan.

SUMMARY

Pediatric urolithiasis is an expanding field, due in part to the apparent increase in cases. Research continues, seeking to refine the appropriate diagnostic and therapeutic approaches in these unfortunate children.

Pediatric stone disease

Urinary stone disease is less common in children than adults. Although many aspects of pediatric stone disease are similar to that of adults, there are unique concerns regarding the presentation, diagnosis, and management of stone disease in children. We present a review of the increasing prevalence of pediatric stone disease, the diagnostic concerns specific to children, recent results from pediatric series regarding the expectant management and surgical treatment of stones, metabolic evaluation, and current research on the genetics of nephrolithiasis.

Endourological management of pediatric stone disease: present status

PURPOSE

The incidence of nephrolithiasis in the pediatric population has been steadily increasing. The miniaturization of endoscopic instruments and improvement in imaging modalities have facilitated safe and effective endourological treatment in this patient population. We reviewed the current status of pediatric stone disease management.

MATERIALS AND METHODS

A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the indications, techniques, complications and efficacy of endourological stone management in children.

RESULTS

In the 1980s shock wave lithotripsy revolutionized stone management in children, becoming the procedure of choice for treating upper tract calculi less than 1.5 cm. Percutaneous nephrolithotomy has replaced open surgical techniques for the treatment of stone burdens greater than 1.5 cm with efficacy and complication rates mirroring those in the adult population. However, at an increasing number of centers ureteroscopy is now being performed in cases that previously would have been treated with shock wave lithotripsy or percutaneous nephrolithotomy. Results from recent retrospective series demonstrate that stone-free rates and complication rates with ureteroscopy are comparable to percutaneous nephrolithotomy and shock wave lithotripsy. Although concerns remain with all endoscopic techniques in children regarding damage to the urinary tract and renal development, neither short-term nor long-term adverse effects have been consistently reported.

CONCLUSIONS

Shock wave lithotripsy, percutaneous nephrolithotomy and ureteroscopy are highly effective endourological techniques to treat stone disease in the pediatric population. A lack of prospective randomized trials comparing treatment modalities coupled with a vast disparity in the access to resources worldwide continues to individualize rather than standardize stone treatment in children.