Our Experience with Totally Ultrasonography-Guided Percutaneous Nephrolithotomy in Children

Tubeless percutaneous nephrolithotomy without retrograde ureteral catheterization for the treatment of pediatric upper ureteral stones: One case report

INTRODUCTION

Traditional Percutaneous Nephrolithotomy (PCNL) typically involves the retrograde placement of a ureteral catheter. However, this procedure can present additional risks in pediatric patients.

CASE PRESENTATION

We report a case of a 10-year-old boy, weighing 33 kg, diagnosed with a right upper ureteral stone complicated by hydronephrosis and urosepsis.

CLINICAL DISCUSSION

Tubeless PCNL without retrograde indwelling ureteral catheter was performed on the second day of hospitalization.

CONCLUSION

This case applied tubeless PCNL without retrograde ureteral catheterization in a single prone position. The procedure was successful and safe.

Retroperitoneal vs transperitoneal laparoscopic pyelolithotomy; a single surgeon's experience

OBJECTIVE

To compare the outcomes of transperitoneal and retroperitoneal laparoscopic pyelolithotomy procedures.

METHODS

A total of 104 consecutive laparoscopic pyelolithotomy surgeries performed by a single surgeon on patients with staghorn or renal pelvic calculi larger than 20 mm were evaluated. Intraoperative and postoperative clinical parameters from two groups, transperitoneal (TLPL) (N = 55) and retroperitoneal (RLPL) (N = 49), were compared. The surgeon performed TLPL for the first five years and then switched to the RLPL approach for the next five years.

RESULTS

There were no significant differences in general demographic variables and stone size (26.55 vs. 24.73 mm, P = 0.8). Operation time and change in serum creatinine levels did not significantly differ between the two approaches. However, patients who underwent TLPL had longer hospital stays than RLPL (3.23 ± 1.21 vs. 2.36 ± 1.10 days, P = 0.0001). Additionally, TLPL was associated with a greater drop in hemoglobin levels (1.53 ± 1.04 vs. 1.17 ± 0.68, P = 0.04), higher rates of postoperative fever (12.7% vs. 0.0%, P = 0.01).

CONCLUSIONS

The retroperitoneal approach in laparoscopic pyelolithotomy for large renal pelvic stones resulted in fewer postoperative fevers, reduced hemoglobin drops, and shorter hospital stays than the transperitoneal approach. However, the stone-free rates were similar for both groups.

Ultrasound-guided renal puncture followed by endoscopically guided tract dilatation vs standard fluoroscopy-guided percutaneous nephrolithotomy for non-opaque renal stones; a randomized clinical trial

This study was designed to evaluate the non-inferiority of ultrasound puncture followed by endoscopically guided tract dilatation compared to the standard fluoroscopy-guided PCNL. Forty patients with non-opaque kidney stones eligible for PCNL were randomly divided into two groups. The standard fluoroscopy-guided PCNL using the Amplatz dilator was performed in the XRAY group. In the SONO group, the Kidney was punctured under an ultrasound guide followed by tract dilatation using a combination of the Amplatz dilator based on the tract length and an endoscopically guided tract dilatation using a bi-prong forceps in cases of short-advancement. The primary outcome was successful access. In 90% of cases in the XRAY and 95% in the SONO group access dilatation process was performed uneventfully at the first attempt (p = 0.5). In 45% of cases in the SONO group, bi-prong forceps were used as salvage for short-advancement. In one case in the X-ray group over-advancement occurred. One month after surgery, the stone-free rate on the CT-scan was 75% for the X-ray group and 85% for the SONO group (p = 0.4). There were no significant differences in operation time, hospitalization duration, transfusion, or complication rates between the two groups. We conclude that ultrasound-guided renal puncture, followed by endoscopically guided tract dilatation can achieve a high success rate similar to X-ray-guided PCNL while avoiding the harmful effects of radiation exposure and the risk of over-advancement.

Total tubeless percutaneous nephrolithotomy without artificial hydronephrosis in preschool children: Three case reports

RATIONALE

Indwelling ureteral catheter, double J tube, or nephrostomy tube are routine procedures for percutaneous nephrolithotomy (PCNL) in children. There are a few cases in which PCNL has been performed in children without any additional instruments being left in place.

PATIENT CONCERNS

In this study, 3 children were treated for hematuria and complicated with different degrees of urinary tract infection. All of them were diagnosed as upper urinary tract calculi by abdominal computed tomography.

DIAGNOSIS

Three preschoolers were diagnosed with upper urinary tract calculi before surgery, one with no hydronephrosis and the other 2 with different degrees of hydronephrosis.

INTERVENTIONS

After preoperative evaluation, all the children successfully completed PCNL without indwelling ureteral catheter, double J tube, or nephrostomy tube.

OUTCOMES

The operation was successful and there were no residual stones observed during postoperative review. The operating times for the children were 33 minutes, 17 minutes, and 20 minutes, and the intraoperative bleeding volumes were 1 mL, 2 mL, and 2 mL. The catheter was removed on the second day after the operation, the postoperative review of the abdominal computed tomography or ultrasound did not indicate any stone residue, and there were no fever, bleeding, and other related complications after the operation.

LESSONS

We believe that total tubeless PCNL without artificial hydronephrosis can be achieved in the preschool population.

Antegrade Percutaneous Retrieval of Upward Migrated Double-J Stent in Very Small Size Pediatric Patients Under Ultrasonic Guide

Purpose: To evaluate the safety of antegrade percutaneous retrieval migrated ureteral stent in very small size pediatric patients with ultramini instruments under ultrasonography guide. Materials and Methods: A total number of 10 out of 115 patients who were referred to our center with upward migrated Double-J (DJ) were candidates for antegrade approach from 2017 to 2020. The pyelocalyceal system was punctured in a prone position by using an 18-gauge disposable needle with Chiba tip and visualization of the upper tract by 3.5 MHz ultrasonic guidance. Then 0.038-inch J tipped guide wire was passed through the needle and the tract was dilated up to 6F under ultrasonographic guide. The 8F access sheath was positioned over the 6F dilator. The semirigid 6F ureteroscope was introduced through the sheath and DJ was removed with a grasper. Results: The mean age was 11.4 ± 5.48 months. The mean time from the previous surgery to DJ removal procedure was 6.4 ± 0.84 weeks. The mean operation time was 11.7 ± 1.76 minutes. All the patients were discharged from the hospital within the 1st day. There were no serious complications (grade 3, 4, or 5) according to Clavien-Dindo classification. Conclusion: The antegrade retrieval of upward migrated DJ with ultramini instrument under ultrasonographic guidance in failed cases of retrograde approach is a safe and effective approach in very small size pediatric patients.

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

Paediatric kidney stone surgery: state-of-the-art review

While urolithiasis in children is rare, the global incidence is rising, and the volume of minimally invasive surgeries being performed reflects this. There have been many developments in the technology, which have supported the advancement of these interventions. However, innovation of this kind has also resulted in wide-ranging practice patterns and debate regarding how they should be best implemented. This is in addition to the extra challenges faced when treating stone disease in children where the patient population often has a higher number of comorbidities and for example, the need to avoid risk such as ionising exposure is higher. The overall result is a number of challenges and controversies surrounding many facets of paediatric stone surgery such as imaging choice, follow-up and different treatment options, for example, medical expulsive therapy, shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. This article provides an overview of the current status of paediatric stone surgery and discussion on the key topics of debate.

Percutaneous nephrolithotomy in horseshoe kidney: comparing ultrasound-guided access in flank position with conventional fluoroscopic-guided in prone position

We conducted this study to compare radiation-free US-guided percutaneous nephrolithotomy (PNL) in the flank position with conventional PNL in the prone position for the treatment of renal stones in patients with horseshoe kidneys. In a retrospective study, 14 HSK patients that were treated with conventional fluoroscopy-guided PNL in the prone position (group A) were compared with twenty-four HSK patients that were treated US-guided PNL in the flank position (group B). Data on baseline characteristics, percentage of successful entries, stone-free rate, duration of admission and complication rate were obtained from data registry. The average duration of the operation was 57.6 min in group B, which was statistically less than group A with 65.9 min (P = 0.001). Access time varied from 10 to 32.4 min (mean = 17.1 min) in group A and 5-29.5 min (mean = 10.9 min) in group B (P < 0.001). Access length had a significant relation to the surgery method so PNL with US-guided had less access length (P = 0.002). There was no significant relationship between the surgery guide and the residual stone rate (P = 0.6). Hemoglobin decrease (P = 0.5), hospitalization duration (P = 0.5) and need for blood transfusion (P value = 0.6) were not statistically different between the two groups. PNL with US guidance in flank position is a safe and effective technique in HSK patients and is associated with fewer complications than the traditional approach as well as reduced operating time, radiation exposure, and its complications.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Totally ultrasound-guided minimally invasive percutaneous nephrolithotomy in children: Is it safe?

OBJECTIVE

The objective of the study was to assess the outcome and feasibility of ultrasonography (US)-guided minimally invasive percutaneous nephrolithotomy (mini-PCNL) in children.

MATERIALS AND METHODS

Twenty-five children with upper urinary tract stones who had undergone US-guided mini-PCNL from June 2017 to June 2020 were enrolled in this study. Patients' demographic information and post-treatment results were retrospectively gathered and analysed. Pyelocaliceal system was punctured in prone position using US guidance, and the tract was dilated using single-shot dilation technique. All steps of renal access were done using only US. Mini-PCNL in all cases was done by using 15 Fr rigid nephroscope. Stones were fragmented with a pneumatic lithotripter and evacuated.

RESULTS

The patients' mean age was 6.30 ± 3.25 years (range: 1.5-15). The mean stone size was 16.04 ± 3.93 mm (range: 10-30). The mean access time to the stone was 1.50 ± 0.62 min (range: 1-4). The mean operation time was 94.66 ± 3.05 min (range: 90-100 min). The final stone-free rate was 96%. Post-operation fever occurred in 4 (16%) patients who were treated successfully with an antibiotic. No major complications occurred.

CONCLUSIONS

We recommend US-guided mini-PCNL as a harmless alternative treatment option, in children with renal calculi due to its excellent outcomes and little complications.

Amplatz versus Balloon for Tract Dilation in Ultrasonographically Guided Percutaneous Nephrolithotomy: A Randomized Clinical Trial

PURPOSE

To compare balloon with Amplatz for tract dilation in totally ultrasonographically guided PCNL (UPCN).

METHODS

We randomized 66 patients candidate for sonographically guided PCNL in the flank position in two study groups. In the first group, we used single step Amplatz dilation (AG) technique in which the 28- or 30-French Amplatz dilator is used for tract dilation. In the other group, we dilated the tract using balloon dilator (BG). We compared procedure time, success rate of dilation, and postoperative clinical outcomes and cost between two groups.

RESULTS

The rate of short dilation was higher in the Amplatz group (57.6%) compared with Balloon group (36.4%) (P=0.08). When using Amplatz for lower pole access, short dilation occurred in 81% of cases compared with 44% in the BG (P=0.02). Overall operation was longer in the AG (80±21 versus 65±20 minutes P=0.02). Stone free rate was 87.9% in the AG compared with 72.7% in the BG (p=0.12). Mean cost of the surgery was 603±85 USD and 718±78 USD in the AG and BG, respectively (P=0.0001). Hemoglobin drop, transfusion rate, renal function alteration, duration of hospitalization, and complication rate based on Clavien classification were similar in both groups.

CONCLUSIONS

AG showed a higher rate of short dilation compared with BG; consequently, overall operating time was significantly longer in the AG whereas BG was significantly more expensive than AG. Bleeding and other complications were similar in two groups. We observed an advantage for balloon dilation over Amplatz when approaching the lower pole calyxes.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Fluoroscopy-free ultrasonography-guided percutaneous nephrolithotomy in pediatric patients: a single-center experience

OBJECTIVES

To present the safety and efficacy of fluoroscopy-free ultrasound-guided PCNL for the treatment of renal calculi in pediatric patients of all ages.

METHODS

30 children with mean age of 5 years (6 months-12 years) underwent totally ultrasound-guided PCNL from March 2013 to August 2016. The pyelocalyceal system was punctured in prone position using only ultrasonography guidance, and the tract was dilated using a single shot dilation technique. No fluoroscopy was used during any of the stages of renal access. The procedure was performed using adult-sized instruments.

RESULTS

The mean stone size was 27.1 ± 8.7 mm. Mean access time was 4.3 ± 2 min. Mean nephroscopic time was 34.6 ± 15.2 min. Mean hospital stay of patients was 3 days (range 2-5). 21 patients were stone-free after the procedure (70% success rate). Only four patients out of 30 experienced postoperative complications.

CONCLUSIONS

The results of this study showed that fluoroscopic-free ultrasound-guided PCNL in pediatric patients of all ages is safe, highly efficient, and minimizes potential radiation exposure risks associated with the procedure.

Use of Ultrasound in Pediatric Renal Stone Diagnosis and Surgery

Pediatric urolithiasis is on the rise globally and incidence rates have risen by 6-10% annually over the past couple of decades. Given the increasing incidence, high likelihood of recurrence, and long life expectancy of children, the use of ionizing radiation in the diagnosis, management, and follow up of pediatric urolithiasis has been scrutinized recently and many institutions and organizations have emphasized the use of non-ionizing imaging modality such as ultrasound. This review examines the use of ultrasound in the diagnosis and treatment of pediatric urolithiasis. Specifically, the role of ultrasound in shockwave lithotripsy, percutaneous nephrolithotomy, and, more recently, ureteroscopy will be examined.

X-ray-free Ultrasound-guided Percutaneous Nephrolithotomy: How to Select the Right Patient?

OBJECTIVE

To identify factors associated with successful ultrasound guidance for each surgical step of ultrasound-guided percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

Consecutive patients undergoing PCNL between March 2015 and June 2016 were prospectively enrolled. An attempt was made to use ultrasound guidance in renal access, tract dilation, and nephrostomy tube placement for each patient. For steps during which ultrasound guidance was unsuccessful, fluoroscopic screening was applied. Regression analysis identified patient characteristics associated with successful use of ultrasound guidance.

RESULTS

A total of 96 patients composed this cohort, with a mean body mass index of 28.7 kg/m2. Mean stone size was 33.1 ± 18.9 mm, and no hydronephrosis was found in 63.5% of cases. Fluoroscopic screening was required for renal access in 27 cases (28.1%), tract dilation in 38 (39.6%), and nephrostomy tube placement in 80 (83.3%). Multivariate analysis demonstrated that successful ultrasound guidance was significantly associated with the presence of hydronephrosis for renal access and the absence of staghorn calculi for tract dilation. Ultrasound-guided nephrostomy tube placement appeared linked to surgeon experience.

CONCLUSION

To achieve completely x-ray-free ultrasound-guided PCNL, the ideal patient should have a hydronephrotic collecting system with no staghorn stone present. For practitioners looking to adopt ultrasound guidance into their PCNL practice, these represent the most appropriate patients to safely initiate a surgical experience.

Clinical effectiveness in the diagnosis and acute management of pediatric nephrolithiasis

The incidence of pediatric nephrolithiasis has risen over the past few decades leading to a growing public health burden. Children and adolescents represent a unique patient population secondary to their higher risks from radiation exposure as compared to adults, high risk of recurrence, and longer follow up time given their longer life expectancies. Ultrasound imaging is the first-line modality for diagnosing suspected nephrolithiasis in children. Although data is limited, the best evidence based medicine supports the use of alpha-blockers as first-line MET in children, especially when stones are small and in a more distal ureteral location. Surgical management of pediatric nephrolithiasis is similar to that in adults with ESWL and URS first-line for smaller stones and PCNL reserved for larger renal stone burden. Clinical effectiveness in minimizing risks in children and adolescents with nephrolithiasis centers around ED pathways that limit CT imaging, strict guidance to ALARA principles or use of US during surgical procedures, and education of both patients and families on the risks of repeat ionizing radiation exposures during follow up and acute colic events.

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.

Solo Sonographically Guided PCNL under Spinal Anesthesia: Defining Predictors of Success

Aim. Sonography has been brought in percutaneous nephrolithotripsy (PCNL) as an adjunct to or substitute for X-ray to restrict radiation exposure. This study was designed to investigate the possible predictors for the success of the solo sonographically guided PCNL. Methods. 148 consecutive cases were prospectively enrolled. All steps of PCNL were performed solely with sonography guidance under spinal anesthesia. Residual stones were evaluated the day after surgery using sonography and plain radiography. Results. The mean age was 46 ± 15 years; 40% of kidneys had hydronephrosis. The mean stone burden was 504 ± 350 mm(2). The mean duration of surgery was 43 ± 21 minutes. The early stone-free rate was 92% in inferior or middle calyceal stones, 89.5% in single pelvic stones, 81.5% in partial staghorn stones, and 61.9% in staghorn stones. The mean residual stone size was 13 ± 8 mm. Logistic regression showed that a lower age and a larger stone burden significantly predicted positive residual stones. Fifteen percent of patients presented with grade I or II and six percent showed grade III complication based on Clavien classification. There was no cases of organ injury or death. Conclusion. Solo ultrasonographically guided PCNL under spinal anesthesia is feasible with an acceptable stone-free rate and complication rate.

Pediatric Kidney Stones - Avoidance and Treatment

Pediatric stone disease is increasing in incidence and healthcare costs. With more years at-risk for stone recurrence during their lifetimes, children with nephrolithiasis constitute a high-risk patient population that requires focused intervention through both medical and surgical means. Through high-quality future studies to compare methods of stone prevention and treatment, the burden of stone disease on the youngest members of society may be ameliorated.

Ultrasound Guidance for Renal Tract Access and Dilation Reduces Radiation Exposure during Percutaneous Nephrolithotomy

Purposes. To present our series of 38 prone percutaneous nephrolithotomy procedures performed with renal access and tract dilation purely under ultrasound guidance and describe the benefits and challenges accompanying this approach. Methods. Thirty-eight consecutive patients presenting for percutaneous nephrolithotomy for renal stone removal were included in this prospective cohort study. Ultrasonographic imaging in the prone position was used to obtain percutaneous renal access and guide tract dilation. Fluoroscopic screening was used only for nephrostomy tube placement. Preoperative, intraoperative, and postoperative procedural and patient data were collected for analysis. Results. Mean age of patients was 52.7 ± 17.2 years. Forty-five percent of patients were male with mean BMI of 26.1 ± 7.3 and mean stone size of 27.2 ± 17.6 millimeters. Renal puncture was performed successfully with ultrasonographic guidance in all cases with mean puncture time of 135.4 ± 132.5 seconds. Mean dilation time was 11.5 ± 3.8 min and mean stone fragmentation time was 37.5 ± 29.0 min. Mean total operative time was 129.3 ± 41.1. No patients experienced any significant immediate postoperative complication. All patients were rendered stone-free and no additional secondary procedures were required. Conclusions. Ultrasound guidance for renal access and tract dilation in prone percutaneous nephrolithotomy is a feasible and effective technique. It can be performed safely with significantly reduced fluoroscopic radiation exposure to the patient, surgeon, and intraoperative personnel.