Single-step percutaneous nephrolithotomy (microperc): the initial clinical report

The modified ultra-mini percutaneous nephrolithotomy technique and comparison with standard nephrolithotomy: a randomized prospective study

To compare the success and complications of ultra-mini percutaneous nephrolithotomy (UPNL) and standard percutaneous nephrolithotomy (SPNL) techniques. We prospectively analyzed 50 patients who underwent SPNL, and 47 patients who underwent UPNL. The patients with a stone size equal to or smaller than 25 mm and we used flipping a coin as the randomization technique. The mean stone size was 20.9 ± 3.6 mm in SPNL, and 20.3 ± 3.0 mm in ultra-mini PNL groups. Stone free rates were 88 % (44/50 patients) and 89.3 % (42/47 patients) in SPNL and UPNL groups, respectively, without any significant difference in between (p = 0.33). No major complications were seen in the UPNL group. PNL has been modified into micro PNL and UPNL parallel to the technological advances to decrease the complications of PNL. When performed as we do UPNL may be an alternative method to SPNL without any additional smaller-calibred nephroscope and with a similar high success rate.

Ultra-mini-percutaneous nephrolithotomy: A minimally-invasive option for percutaneous stone removal

Introduction:

Percutaneous nephrolithotomy (PCNL) has witnessed rapid advancements, the latest being ultra-mini-percutaneous nephrolithotomy (UMP), which makes the use of 11–13F sheaths as compared to 24–30F sizes used in conventional PCNL. This miniaturization aims to reduce morbidity and improve patient outcomes. We evaluated the safety and efficacy of UMP and report our ourtcomes.

Patients and Methods:

A total of 120 patients underwent UMP from July 2012 to March 2014. These patients had a single unilateral renal stone measuring between 8 and 20 mm. All patients underwent UMP using a 3F nephroscope, 7.5F inner sheath, and 11F or 13F outer metallic cannula, which served as the Amplatz sheath. Stone fragmentation and clearance were achieved with holmium laser. No nephrostomy or stent was used routinely.

Results:

Complete stone fragmentation was achieved in 114 out of 120 patients (95%) using UMP; whereas the remaining 6 were converted into mini-PCNL using a 12.5F nephroscope and 15F Amplatz sheath. The mean operative time was 39.7 ± 15.4 min, and the mean postoperative hospital stay was 22.3 ± 2.2 h. Postoperatively, 6 (5%) patients had residual fragments measuring ≤4 mm. At the 2 weeks follow-up, the stone-free status was >99% (119/120). There were no significant postoperative complications.

Conclusion:

This study shows UMP to be an effective and safe procedure for managing stones up to 20 mm. This procedure offers an attractive alternative to shock wave lithotripsy and retrograde intrarenal surgery for managing small stones.

Comparison of Retrograde Intrarenal Surgery and Micro-Percutaneous Nephrolithotomy in Moderately Sized Pediatric Kidney Stones

PURPOSE

To compare the effectiveness and reliability of retrograde intrarenal surgery (RIRS) and micro-percutaneous nephrolithotomy (micro-perc) for the management of kidney stones in pediatric patients.

MATERIALS AND METHODS

A retrospective analysis was made of pediatric patients aged <18 years with kidney stones that ranged from 10 to 20 mm in size, who underwent RIRS (n = 36) or micro-perc (n = 45) in referral centers.

RESULTS

In the RIRS group, the mean age of patients was 8.39 ± 4.72 years and in the micro-perc group, it was 5.62 ± 4.50 years (p = 0.01). The mean stone size was 12.80 ± 3.03 mm in the RIRS group and 13.97 ± 3.46 mm in the micro-perc group (p = 0.189). The success rate was 86.2% (n = 31) in the RIRS group and 80.0% (n = 36) in the micro-perc group (p = 0.47). The mean complication rate was 16.6% and 13.3% in the RIRS and micro-perc groups, respectively (p = 0.675). Hospital stay and radiation exposure were significantly lower in the RIRS group (all p < 0.001). The mean anesthesia session was 1.94 in the RIRS group and 1.26 in the micro-perc group (p < 0.001). The mean hemoglobin drop was 0.53 ± 0.87 g/dL in the micro-perc group, and none of the cases required blood transfusion.

CONCLUSION

The results of this study suggested that micro-perc and RIRS were highly effective methods for the treatment of moderately sized renal stones in children, with comparable success and complication rates. Patients and their parents should be informed about the currently available treatment options, and of their efficacy and safety. However, further clinical trials are needed to support these results.

Micro-percutaneous nephrolithotomy in the treatment of pediatric nephrolithiasis: A single-center experience

OBJECTIVE

We aimed to clarify the applicability and safety of micro-PNL (microperc) in the treatment of pediatric kidney stones.

MATERIAL AND METHODS

A single center prospective trial was initiated, and microperc was performed in 40 children using the same two methods: the classical all-seeing needle and microsheath method. Stone fragmentation was performed using a 200-μm holmium:YAG laser fiber.

RESULTS

The mean age of the patients was 6.3±4.4years (range: 7months-16years). Fourteen were less than 3years old. The average calculous size was 16.5mm (range: 10-36mm). In 20 patients, access was achieved through the all-seeing needle method. In the other patients, access was achieved by the microsheath method. Conversion to mini-PNL was required in 2 patients due to intraoperative bleeding in one and a high stone burden in the other. The mean hospital stay was 3.8±1.2days (range: 1-10days), and the mean hemoglobin decrease was 0.7±0.3mg/dl (range: 0-1.7mg/dl).The duration of surgery and fluoroscopic screening was 75min and 3.7min, respectively. A DJ stent was placed in 11 patients due to a high stone burden. A ureteral stent was left for 1day in the rest of the cases. Complete clearance was achieved in the other 32 children. None of the patients required transfusion caused by renal hemorrhage. In 1 patient, extravasation of the irrigation fluid caused abdominal distention. As assessed by KUB and/or an ultrasound, the overall stone-free rate at 6weeks was 80%. There were residual fragments in 6 patients (15%).

CONCLUSIONS

Our results show that microperc is a safe and effective procedure for the treatment of pediatric kidney stones. Children with small renal calculi and with nonobstructed collecting systems are suitable for microperc.

Bilateral microperc in a severe kyphoscoliosis

Percutaneous nephrolithotomy is the standard modality for large renal calculi in normal and abnormal renal anatomic situations. This case report describes a 57-year-old male patient who presented with bilateral kidney stones and severe kyphoscoliosis. He had successfully been treated with a bilateral microperc technique.

STPEDISET: A novel innovation for percutaneous nephrolithotomy in children

PURPOSE

The aim of this study was to report the outcomes of PCNL in patients in whom the Short and Thin Pediatric Set (ST PEDISET) had been used.

METHODS

Data from 21 patients (11 boys and 10 girls) who underwent PCNL for renal stones using the ST PEDISET between April 2013 and February 2015 were analyzed retrospectively. The patients were evaluated by plane radiography and USG after surgery.

RESULTS

In total 21 children (11 boys and 10 girls) with a median age of 13months (range 5months to 4years) who underwent PCNL were included in the study. The median stone burden was 16mm (range 10-36mm). The success rate was 85.7%. Sixteen patients (76.2%) were stone free and two patients (9.5%) had clinically insignificant residual fragments (CIRF). The median length of hospital stay was 4days (range 2-9days).

CONCLUSIONS

The data of this study clearly show that the ST PEDISET is safe, effective and ergonomic for percutaneous nephrolithotomy in preschool-age children. This study indicates the need for randomized trials on larger cohorts to confirm these findings, and thus improve the surgical procedure.

'Mini, ultra, micro' - nomenclature and cost of these new minimally invasive percutaneous nephrolithotomy (PCNL) techniques

New minimally invasive percutaneous nephrolithotomy (PCNL) techniques have changed the management of renal stones. We discuss the technological advances in PCNL and explain the meaning, requirements and set up costs for each of these 'newer' techniques.

A comparison of outcomes after percutaneous nephrolithotomy in children and adults: a matched cohort study

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) has surpassed open stone surgery as the operation of choice for large and complex stone burdens (figure). Although the procedure was developed in adults, its principles have been extrapolated to children. There is a paucity of literature comparing outcomes of PCNL in adults and children for similar stone burdens.

OBJECTIVE

The purpose of this study was to evaluate outcomes following PCNL among children and adults with similar stone burdens.

PATIENTS AND METHODS

Data on patient characteristics and outcomes for 2196 consecutive patients undergoing PCNL at a single institution were collected prospectively from January 1992 to July 2013. Thirty-one pediatric patients undergoing 39 PCNLs were identified. Each pediatric PCNL was matched in a ratio of 1:4 to adult PCNLs by year of surgery and stone burden characteristics (staghorn, partial staghorn, number of stones). All PCNLs were performed by two fellowship-trained endourologists who operate on both adult and pediatric patients. Ultrasonic lithotripsy was used primarily. The primary outcome measure was stone-free rate (SFR) at hospital discharge. Secondary outcomes included the need for second-look nephroscopy, length of hospital stay, complication rate, and blood transfusion rate. The Student t test was used for continuous variables and the Fisher exact for categorical variables.

RESULTS

The median age for the pediatric group was 13.9 ± 4.30 years and for the adult group was 55.4 ± 15.1 years. Pediatric patients tended to present with metabolic stones, with no difference in rates of infection stones. No difference was found in SFR at time of hospital discharge (86.1% vs. 86.4%, p = 0.2). More pediatric patients required a second access tract than adult patients (15.4% vs. 4.52%, p = 0.02). There was no significant difference in the need for second-look nephroscopy, length of stay, or complication rates (overall and by Clavien classification subgroup) between both groups. The rates of blood transfusion were low in both groups (0% vs. 0.6%, p = 0.80).

DISCUSSION

There was no difference in primary and secondary outcomes among children compared with adults undergoing PCNL in our study. The outcomes reported in this study were similar to published literature. A limitation of this study is the low number of pediatric patients. However, it is unique to have a single-center study that compares PCNL outcomes in both adult and pediatric patient and accounts for stone burden characteristics.

CONCLUSIONS

Although principles of PCNL were developed in adults, this study affirms the safety and efficacy of PCNL in both pediatric and adult patients.

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.

Recent advancement or less invasive treatment of percutaneous nephrolithotomy

Since its initial introduction in 1976, percutaneous nephrolithotomy (PCNL) has been widely performed for the management of large renal stones and currently is recommended for staghorn calculi, kidney stones larger than 2 cm, and shock wave lithotripsy-resistant lower pole stones greater than 1 cm. However, except for open and laparoscopic surgery, PCNL is the most invasive of the minimally invasive stone surgery techniques. Over the years, technical and instrumental advances have been made in PCNL to reduce morbidity and improve effectiveness. A thorough review of the recent literature identified five major areas of progress for the advancement of PCNL: patient positioning, method of percutaneous access, development of lithotriptors, miniaturized access tracts, and postoperative nephrostomy tube management. This review provides an overview of recent advancements in PCNL and the outcomes of each area of progress and notes how much we achieve with less invasive PCNL. This information may allow us to consider the future role and future developments of PCNL.

Micropercutaneous nephrolithotripsy: initial experience

INTRODUCTION

For small renal calculi (< 2 cm) the currently available treatment options include extracorporeal shockwave lithotripsy (ESWL), retrograde intrarenal surgery (RIRS) and standard/mini percutaneous nephrolithotomy (PNL). A new method, microperc, has therefore been developed, in which a smaller tract size and smaller instruments were used.

AIM

To present our clinical experiences with micropercutaneous nephrolithotripsy (microperc) in the treatment of small renal calculi.

MATERIAL AND METHODS

We retrospectively evaluated patients with small renal calculi who underwent microperc between February and June 2013. A 4.8 Fr 'all-seeing needle' was used to achieve percutaneous renal access with the C-arm fluoroscopy guidance in the prone position. Holmium: YAG laser 272 µm fiber was used for stone fragmentation.

RESULTS

A total of 20 patients underwent the microperc procedure. The mean age of the patients was 46.5 ±13.8 years. The mean stone size was 13 ±3 mm. The stone-free rate (SFR) was 90% (18/20). Two patients had clinically significant residual fragments (≥ 4 mm). The mean operation and fluoroscopy times were 107.5 ±37 min and 45 ±40 s respectively. The mean postoperative drop in hemoglobin was 1.2 ±0.9 g/dl, and 1 patient required blood transfusion. The patients were discharged after an average hospitalization of 1.4 ±0.8 days. Two complications, urinary tract infection and blood loss requiring blood transfusion, were observed in 2 patients postoperatively.

CONCLUSIONS

We suggest that microperc should be considered for the treatment of small renal stones.

Miniperc and retrograde intrarenal surgery: when and how?

CONTEXT

Extracorporeal shock wave lithotripsy (ESWL) and percutaneous nephrolithotomy (PCNL) are consolidated procedures for the treatment of kidney stones; however, their primary weak points are the lower efficacy of ESWL, especially for lower calyx stones, and the morbidity of PCNL resulting from the creation and dilation of the percutaneous trajectory. The increasing miniaturization of percutaneous surgery instrumentation and the development of retrograde intrarenal surgery (RIRS) are recent innovations.

ACQUISITION OF EVIDENCE

A structured nonsystematic review was conducted through a literature search of articles published between 1997 and 2013, using the terms kidney stones, miniperc, mini-PCNL, RIRS and flexible ureteroscopy in the PubMed, Google Scholar and Scopus databases.

SUMMARY OF THE EVIDENCE

RIRS requires greater surgical time, several procedures for voluminous stones and higher hospital costs, due in part to the relative fragility of the instruments. On the other hand, miniperc requires a longer hospital stay, an increased need for postoperative analgesia and a greater reduction in hemoglobin levels, although these do not translate into an increased rate of transfusions.

CONCLUSIONS

The current treatment of kidney stones uses minimally invasive procedures such as miniperc and RIRS. The 2 procedures are equivalent in terms of efficacy (stone clearance) and are associated with minimal complications. Comparative prospective studies are necessary to determine the position of each of these techniques in the treatment of kidney stones. In our experience, the 2 techniques are complementary and should be part of the current urological therapeutic arsenal.

Implementation of Ultramini Percutaneous Nephrolithotomy for Treatment of 2-3 cm Kidney Stones: A Preliminary Report

BACKGROUND AND PURPOSE

Miniatured percutaneous nephrolithotomy (PCNL) techniques such as micro-PCNL (microperc) and ultramini-PCNL (UMP) are usually indicated for renal stones <2 cm. We present our preliminary report of treating patients with 2 to 3 cm renal stones using UMP in a semisupine combined lithotomy position associated with a retrograde ureteral access sheath (UAS).

METHODS

From April 2013 to January 2014, we implemented 13F UMP for 22 patients with renal stones that were 2 to 3 cm with the patient positioned in a 45-degree semisupine combined lithotomy position. A retrograde 9.5/11.5F UAS was placed for maintaining low intrarenal pressure and debris drainage. Flexible ureteroscopy was used for stones inaccessible through the primary percutaneous tract in two patients. A 200-μ holmium laser was used for stone disintegration. Intrapelvic pressure was measured using an open end 5F ureteral catheter inserted through the UAS.

RESULTS

All 22 cases were completed successfully. The mean preoperative stone size was 26.6 ± 4.7 mm (range 21-32 mm), mean operative time was 85.7 ± 18.0 minutes (range 47-112 min), and mean hemoglobin drop was 1.2 ± 0.3 g/dL (range 0.5-2.2 g/dL). Intrapelvic pressure during the surgical procedure ranged 5 to 10 cm H2O. The mean hospital stay was 3.1 ± 1.8 days (range 2-5 d). Complete stone clearance was 18/22 (81.8%) with solo UMP and 20/22 (90.9%) when associated with retrograde intrarenal surgery (RIRS). No major intra- or postoperative complications occurred.

CONCLUSION

Implementation of UMP for the treatment of patients with renal stones 2-3 cm is feasible and safe. The procedure is less invasive and has a faster recovery period. Intraoperative retrograde UAS decreases intrarenal pressure, facilitates removal of stone fragments, and also allows simultaneous RIRS for stones in an inaccessible calix.

Micro-percutaneous nephrolithotomy in infants: a single-center experience

This study aimed to investigate the effectiveness and reliability of micro-percutaneous nephrolithotomy (micro-PNL) for the management of kidney stones in pediatric patients. This retrospective study included 24 infants that underwent micro-PNL for renal stones between March 2012 and April 2015. The inclusion criteria included: age younger than 2 years, stone size <20 mm, absence of urinary tract malformations and active infection, and no coagulopathy. Stone-free rates were assessed one month postoperatively by ultrasonography (USG) and kidneys, ureters, bladder (KUB) radiography. Complications were classified according to the Clavien classification system. The mean age of the patients was 15.8 ± 7.8 months (range, 8-23) and the mean stone size was 13.5 ± 3.84 mm. Intra-renal access was achieved using USG in 11 patients and KUB fluoroscopy in 13 patients. The operation time and fluoroscopic screening time were 53.7 ± 10.35 and 1.4 ± 0.9 min, respectively. The mean hospital stay was 2.5 ± 0.8 days, and the mean drop in the hemoglobin level was 0.51 ± 0.34 g/dL. Bleeding requiring blood transfusion was not observed. A ureteral J stent was implanted perioperatively in four patients because of stone burden. Four patients complained of postoperative renal colic (Clavien grade 1) and postoperative fever was observed in two patients. Definitive success rates were as follows: the stone-free rate was 83.3% (n = 20) and residual fragments were observed in four patients.

Ultramini nephrostomy tract combined with flexible ureterorenoscopy for the treatment of multiple renal calculi in paediatric patients

Purpose

To assess the safety and efficacy of an ultramini nephrostomy tract, which we were using for the first time, combined with flexible ureterorenoscopy (URS) in the treatment of pediatric patients with multiple renal calculi.

Materials and Methods

Twenty pediatric patients (age, ≤6 years) underwent ultramini percutaneous nephrolithotomy (PCNL) combined with flexible URS. The group had multiple renal calculi, which were bilateral in 3 cases and were located in a total of 23 sites. The calculi were located in 2 calyces in 10 cases, scattered in more than 2 calyces in 7 cases, and limited to 1 calyx in 3 cases. The average patient age was 37.35 months (range, 14-68 months). The average stone diameter was 2.0 cm (range, 1-3.0 cm). In all patients, an ultramini nephrostomy tract was established under ultrasound guidance (dilated to F10) with simultaneous sheath placement. The flexible URS was placed into the collecting system during holmium laser lithotripsy.

Results

When ultramini PCNL was combined with flexible ureterorenoscopic holmium laser lithotripsy, the complete stone-free rate was 87% (20/23). The average level of hemoglobin decreased to 1.0 g/dL after the operation. No blood transfusions were needed. Levels of blood urea nitrogen, creatinine, and C-reactive protein were not significantly different before and after the operation. The average duration of hospitalization was approximately 4.85 days, and all cases were followed up for 6 to 12 months. No complications were found.

Conclusions

Ultramini PCNL combined with flexible ureterorenoscopic holmium laser lithotripsy is a safe and effective treatment for children with multiple renal calculi.

Retrograde intrarenal surgery in the management of symptomatic calyceal diverticular stones: a single center experience

To evaluate the outcome of RIRS in managing symptomatic calyceal diverticular as a minimally invasive option, we retrospectively reviewed the records of 43 patients who underwent RIRS from 2005 to 2014 for symptomatic calyceal diverticular stones. A month after the initial operation, the success rate was (81.4%, 35 patients) of which 21 (48.83%) patients were stone free and 14 (32.6%) patients had clinically insignificant residual fragments (CIRFs), and 90% patients were symptom free. Eight patients (16.6%) had significant residual fragments (>3 mm), five of them became completely stone free after the second procedure, other three patients were symptom free and underwent a routine follow-up. The final treatment success rate was 93.0%. The initial success rate in the lower calyx was significantly lower than the other calices (P = 0.040). In addition, the association between the stone size and the initial treatment success was significant (P = 0.036). There was no association between any of our other variables and the success rate. The mean first operative time was 60.95 ± 12.43 min (range 34-92). No major complication (Clavien III-V) occurred, although there were five minor complications (11.6%) (Clavien I-II). There were no admissions to intensive care or deaths in our series, the mean hospitalization time was 1.77 ± 0.80 days. The management of calyceal diverticular calculus with RIRS is highly effective and can be accomplished with low morbidity.

Micro-ureteroscopy: Initial experience in the endoscopic treatment of pelvic ureteral lithiasis

OBJECTIVES

To present to report the first case of ureteral lithiasis resolved using a new endoscopic approach, which we call microureteroscopy (m-URS) and attempts to reduce the ureteral damage caused by conventional instrumentation.

MATERIAL AND METHODS

We selected a 53-year-old patient with a 16-mm calculus in the right distal ureter. For endoscopic access, we used a 4.8 Fr sheath from the microperc set and fragmented the stone with a 230-micron laser fiber.

RESULTS

Complete fragmentation of the stone was achieved. We placed a JJ catheter due to significant ureteral edema. The surgical time and postsurgical stay were 156minutes and 24hours, respectively. There were no complications, the requirements for analgesia were minimal, and the patient was free of residual stones.

CONCLUSIONS

The m-URS technique is feasible, simple and effective for the treatment of pelvic ureteral lithiasis in women and optimizes minimal invasion, with results that can be comparable to conventional endoscopic techniques in terms of ease of access and quality of endoscopic vision without affecting the resolution capacity. Larger studies and greater technological development is needed to define the definitive role of this procedure. Currently, its major limitations lie in the treatment of proximal ureter lithiasis and in the treatment of men. This technique could also be a viable alternative for pediatric patients.

Treatment of symptomatic lower pole stones of a kidney with partial nephrectomy using micropercutaneous nephrolithotomy technique

We present the treatment of lower pole stones of a 62-year-old male patient with a history of open partial nephrectomy due to renal angiomyolipoma and renal stones. He was successfully treated with micropercutaneous nephrolithotomy technique under spinal anesthesia in spite of fibrotic and scar tissue due to previous open surgery. The patient was stone-free and was discharged after a 24-hour hospitalization period. There is not any published report of micropercutaneous nephrolithotomy in a partial nephrectomized kidney before. In this report, we suggest that microperc technique may be considered for challenging conditions in case of failed retrograde intrarenal surgery.

Urovision 2020: The future of urology

Urology, as a specialty, has always been at the forefront of innovation and research. Newer technologies have been rapidly embraced and, in many cases, improved upon in order to achieve better patient outcomes. This review addresses the possible future directions that technological advances in urology may take. The role of further miniaturization of urolithiasis treatment, robotic surgery and other minimally invasive techniques is addressed. The potential for enhanced imaging and diagnostic techniques like magnetic resonance imaging and ultrasonography modifications, as well as the potential applications of nanotechnology and tissue engineering, are reviewed.

This article is based on the Dr. Sitharaman Best Essay award of the Urological Society of India for 2013.

Contemporary Management of Medium-Sized (10-20 mm) Renal Stones: A Retrospective Multicenter Observational Study

PURPOSE

To evaluate contemporary management approaches to medium-sized (10-20 mm) renal stones.

PATIENTS AND METHODS

A total of 935 patients treated for medium-sized renal stones (10-20 mm) between July 2012 and March 2014 were included in the study program. Contemporary minimally invasive approaches applied in the management of such stones were evaluated and compared.

RESULTS

The cohort consisted of 561 male (60%) and 374 female (40%) patients. Of the 935 patients with medium-sized renal calculi, 535 (57.2%) were treated with shockwave lithotripsy (SWL), 201 (21.4%) with retrograde intrarenal surgery (RIRS), 110 (11.7%) with minimally invasive percutaneous nephrolithotomy (miniperc), and the remaining 89 (11.7%) patients with micropercutaneous nephrolithotomy (microperc). In the SWL group, stones were located mostly in the pelvis (51%), while in the miniperc and microperc groups, they were located mainly in the lower pole (46%, 53%, respectively). Stone-free rates after a single session were 77.2%, 86.1%, 88.8%, and 83.6% in the SWL, RIRS, microperc, and miniperc groups, respectively. Although no serious complications (above Clavien level III) were noted in any of the groups evaluated, Clavien I to II complications were common in the miniperc group.

CONCLUSION

Although SWL is the preferred treatment option for patients with medium-sized (10-20 mm) renal stones, endourologic methods also have been found to have a significant role. Relatively lower complication rates along with higher stone-free status observed with the RIRS technique compared with percutaneous approaches have made this method a valuable option in the management of such stones in recent years.

Comparison of flexible ureterorenoscopy and micropercutaneous nephrolithotomy in the treatment for moderately size lower-pole stones

PURPOSE

To present a retrospective comparative clinical study of micropercutaneous nephrolithotomy (microperc) versus flexible ureterorenoscopy (F-URS) in treatment of moderate-size lower-pole stones (LPSs).

METHODS

We retrospectively reviewed data on patients with isolated LPSs ≤2 cm in diameter treated with F-URS and/or microperc in two referral centers. Patients were divided into two groups by treatment modality: F-URS (Group 1) and microperc (Group 2). Demographics and perioperative parameters were analyzed.

RESULTS

A total of 127 patients with isolated LPSs were treated via F-URS (Group 1, n = 59) and microperc (Group 2, n = 68). Mean patient age in microperc group was slightly lower than in F-URS group (p = 0.112). We found no statistically significant difference in terms of either the size or number of stones in two groups (p = 0.113 and p = 0.209, respectively). Operative time was shorter in microperc, whereas fluoroscopy time was shorter in F-URS (60.1 ± 26.2 vs. 46.2 ± 24.3 min, p < 0.001; and 28.3 ± 19.1 vs. 108.9 ± 65.2 s, p < 0.001). Mean fall in hemoglobin level was statistically significantly lower in F-URS and hospitalization time was also significantly shorter in F-URS (0.68 ± 0.51 vs. 1.29 ± 0.88 mg/dL, p < 0.001; and 23.0 ± 58.1 vs. 33.8 ± 17.2 h, p < 0.001, respectively). Stone-free rates (SFRs) were 74.5 % (44/59) in Group 1 and 88.2 % (60/68) in Group 2 (p < 0.001).

CONCLUSIONS

We found that microperc was safe and efficacious when used to treat moderate-size LPSs and may be considered as an alternative to F-URS, affording a higher SFR. Our study supports the notion that microperc should play an increasing role in treatment of LPSs.

Is Micropercutaneous Nephrolithotomy Technique Really Efficacicous for the Treatment of Moderate Size Renal Calculi? Yes

OBJECTIVE

To present our clinical experiences with micropercutaneous nephrolithotomy in the treatment of moderate-sized renal calculi from a single center.

METHODS

We retrospectively evaluated the patients with moderate-sized renal calculi who underwent micro-percutaneous nephrolithotomy between December 2012 and Septermber 2013.

RESULTS

A total of 68 patients and 70 renal units underwent microperc procedure. Mean age of patients was 41.4 ± 18.8. The mean stone size was 122 ± 83 mm(2). The operations were performed under spinal anesthesia in 89.7% of the patients. Stone-free rate was 95.7 % (67/70). Clinically significant residual fragments were observed in three patients. The average duration of operation and mean fluoroscopy time was 40 ± 23 min and 108 ± 72 s, respectively. The mean postoperative drop in hemoglobin was 0.95 ± 0.7 while no patient required blood transfusion. Patients were discharged after an average hospitalization time of 27.5 ± 12.4 h. A total of 4 complications (5.7%), including urinary tract infection (Clavien I) in one patient and renal colics requiring stent insertion (Clavien IIIa) in three patients, were observed postoperatively.

CONCLUSION

Microperc technique is safe, feasible, and efficacious. We suggest that micro-percutaneous nephrolithotomy should be considered for the treatment of moderate-sized renal stones as an alternative to SWL and RIRS failures and also may be considered even primarily.

Appropriate kidney stone size for ureteroscopic lithotripsy: When to switch to a percutaneous approach

Flexible ureteroscopy (fURS) has become a more effective and safer treatment for whole upper urinary tract stones. Percutaneous nephrolithotomy (PNL) is currently the first-line recommended treatment for large kidney stones ≥ 20 mm and it has an excellent stone-free rate for large kidney stones. However, its invasiveness is not negligible considering its major complication rates. Staged fURS is a practical treatment for such large kidney stones because fURS has a minimal blood transfusion risk, short hospitalization and few restrictions on daily routines. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. Therefore, in our opinion, staged fURS is a practical option for kidney stones 20 to 40 mm. Miniaturized PNL combined with fURS should be considered to be a preferred option for stones larger than 40 mm. Moreover, URS is an effective treatment for multiple upper urinary tract stones. Especially for patients with a stone burden < 20 mm, URS is a favorable option that promises a high stone-free rate after a single session either unilaterally or bilaterally. However, for patients with a stone burden ≥ 20 mm, a staged operation should be considered to achieve stone-free status.

Treatment alternatives for urinary system stone disease in preschool aged children: results of 616 cases

INTRODUCTION

The treatment of stone disease is mostly similar in those adult and children. The standard treatment procedures are as follows: extracorporeal shock wave lithotripsy (ESWL), ureterorenoscopy (URS), percutaneous nephrolithotomy (PCNL), and laparoscopic surgery in selected cases. Open surgery (OS) is another option particularly in such cases with anatomic abnormalities of urinary tract.

OBJECTIVE

The present study aims to provide comparative results of stone removal procedures in preschool aged patients who were diagnosed with urinary system stone disease.

STUDY DESIGN

The retrospective data of 616 pediatric preschool patients consulted with urinary system stone disease between January 2009 and July 2013 were evaluated. All patients were evaluated with Kidney-Ureter-Bladder (KUB) Xray and abdomino-pelvic ultrasound. Intravenous pyelography, unenhanced computed tomography (CT), and renal scintigraphy were performed when needed. Patients were categorized according to the procedures as: Group ESWL, Group URS, Group PNL, Group micro-PNL and Group OS. Following the procedures, opaque residual stones were evaluated with KUB Xray, and non-opaque residual stones were evaluated with unenhanced CT.

RESULTS

In groups (ESWL, URS, PNL, micro-PNL, OS), the stone-free rate was 68%, 66%, 85%, 100% and 94 %, respectively. The stone analysis were observed as, calcium oxalate in 377 patients (61.2%), uric acid in 106 patients (17.2%), infection stone in 73 patients (11.8 %), and cysteine in 60 patients (9.7%). There was no significant difference in stone analysis between the groups (p > 0.05) (Table).

DISCUSSION

Minimally invasive procedures are frequently preferred in the pediatric age urinary system stone disease. These procedures are ESWL, PCNL, and ureteroscopy [10,11]. Open surgery is reserved only for rare cases [12]. Similarly the current literature, 18 (2.9%) patients had anatomical anomaly and had high complex stone burden were treated with open surgery in our study. ESWL is a preferred treatment method for pediatric urolithiasis patients with a stone size <20 mm, and the rate of stone-free after ESWL ranges between 57 and 92% [13]. In a study showed the effect of stone size on the success rate in ESWL, the success rate was 91% for stones <10 mm, and 75% for stones >10 mm [15]. In the present study, stone-free rate was noted as 68% on 15 mm or lower stone size. PNL is commonly used to treat stone disease in preschool children [18-20]. In the beginning, urologists hesitated to use instruments suited for adults in case of pediatric kidneys. While some authors accept a cut-off value of 24 F for tract dilatation in the pediatric age, Desai et al. recommended a threshold value <22 F [19,21]. In our study, we used adult PNL instruments in the early period, whereas mini-PERC was performed in the later years. The success rate in PNL group was found as 85%. In recent years, the micro-PNL procedure has been developed to reduce/prevent the complications of standard PNL. In our study, the success rate was calculated as 100% with micro-PNL. This study has certain limitations. The major limitation of our study is its retrospective nature. In addition, sample size of micro-PNL group is fewer than other groups.

CONCLUSION

The goal of kidney stone treatment is to achieve minimal kidney damage and a high success rate. Thus, the procedures are important in the pediatric age group where life expectancy is high, and particularly in the preschool age group.

Is micro-percutaneous nephrolithotomy surgery technically feasible and efficient under spinal anesthesia?

The objective of the study was to present the clinical and operative effects of two types of anesthesia on micro-percutaneous nephrolithotomy ("microperc"). We retrospectively reviewed 116 patients who underwent microperc between August 2011 and September 2013. Patients were sorted into one of the two groups according to the type of anesthesia received: general (Group 1, n:53) or spinal (Group 2, n:63). Perioperative variables (age, stone size, location) and outcomes (operation time, success, complication rate) were evaluated and compared. Although there was a statistically significant difference in the mean age of patients (30.3 ± 22.1 vs. 45.8 ± 14.6, respectively, p < 0.001), mean body mass indexes were similar (p = 0.689). There was no substantial difference in terms of sizes and localizations of stones in the two groups (p = 0.970 and p = 0.795). While a significant difference was found in comparison of operative times (59.62 ± 32.56 vs. 40.98 ± 26.45 min, p < 0.001), there was no statistically significant difference in mean fluoroscopy times (124.92 ± 84.2 vs. 105.2 ± 61.0 s, p = 0.441). Stone-free rates were similar (90.5% vs. 93.6%, p = 0.297). We found no statistical differences between the two groups with respect to mean hemoglobin drop and hospitalization time (p = 0.015 and p = 0.917, respectively). The complication rates and analog pain scores were also similar (p = 0.543 and p = 0.365). Our results show that microperc is a feasible surgical modality in the treatment of kidney stone disease under both spinal and general anesthesia. Spinal anesthesia may be considered for patients at a high risk for general anesthesia, and also may be an alternative for patients who are concerned about and/or fearful of general anesthesia.

Does the presence of hydronephrosis have effects on micropercutaneous nephrolithotomy?

PURPOSE

To evaluate the effects of presence of hydronephrosis on micropercutaneous nephrolithotomy (micro-PNL) surgery.

PATIENTS AND METHODS

A retrospective analysis of 112 patients who underwent microperc surgery between December 2012 and April 2014 was performed. Patients were evaluated in two groups according to whether the presence of hydronephrosis. Stone size and location, fluoroscopy and operation time, stone-free rates and patient-related parameters were prospectively recorded into a centralized computer-generated system.

RESULTS

A total of 58 patients in Group 1 with hydronephrosis and 54 patients in Group 2 with no hydronephrosis were analyzed. There was no statistically significant difference in terms of stone sizes and body mass indexes (BMI) in comparison of groups (155.2 ± 93.06 vs. 143.70 ± 70.77 mm(2), p = 0.856 and 27.6 ± 4.2 vs. 26.7 ± 3.2 kg/m(2), p = 0.625). The success rates were similar (91.3 vs. 92.5%, p = 0.341). While the mean operation time and fluoroscopy time in Group 1 were 44.2 ± 23.62 min and 105.3 ± 47 s, it was 38.8 ± 26.4 min and 112.53 ± 68.3 s in Group 2, but there was no statistical difference in comparison of both groups. The mean attempts of percutan puncture were 1.35 ± 0.47 in Group 1 and 1.76 ± 0.31 in Group 2 (p = 0.185). We also found no statistical differences regarding mean hemoglobin change and hospitalization time, respectively (p = 0.685 and p = 0753). In comparison of grades of hydronephrosis, there was no statistically significant difference in subgroups analysis.

CONCLUSIONS

The presence of hydronephrosis does not affect success rates and operative time in micro-PNL procedures significantly. Micropercutaneous nephrolithotomy is technically feasible and efficacious both in hydronephrotic and non-hydronephrotic kidneys.

Retrograde intrarenal surgery in pediatric patients

Urinary tract stone disease is seen at a level of 1%-2% in childhood (< 18 years). In recent years, however, there has been a marked increased in pediatric stone disease, particularly in adolescence. A carbohydrate- and salt-heavy diet and a more sedentary lifestyle are implicated in this increase. Although stone disease is rare in childhood, its presence is frequently associated with metabolic or anatomical disorders or infectious conditions, for which reason there is a high possibility of post-therapeutic recurrence. Factors such as a high possibility of recurrence and increasing incidence further enhance the importance of minimally invasive therapeutic options in children, with their expectations of a long life. In children in whom active stone removal is decided on, the way to achieve the highest level of success with the least morbidity is to select the most appropriate treatment modality. Thanks to today’s advanced technology, renal stones that were once treated only by surgery can now be treated with minimally invasive techniques, from invasion of the urinary system in an antegrade (percutaneous nephrolithotomy) or retrograde (retrograde intrarenal surgery) manner or shock wave lithotripsy to laparoscopic stone surgery. This compilation study examined studies involving the RIRS procedure, the latest minimally invasive technique, in children and compared the results of those studies with those from other techniques.

Comparative study of retrograde intrarenal surgery and micropercutaneous nephrolithotomy in the treatment of intermediate-sized kidney stones

OBJECTIVE

Retrograde intrarenal surgery (RIRS) has proven efficacy with minimal morbidity in the treatment of intermediate-sized kidney stones. The aim of this study was to examine the feasibility of micropercutaneous nephrolithotomy (microperc) for this indication and evaluate its results compared with those of RIRS.

MATERIAL AND METHODS

From September to December 2013, we performed a comparative prospective study between RIRS and microperc, with 20 consecutive patients with intermediate-sized (1-3cm) kidney stones. We employed a flexible dual-channel ureteroscope (Cobra, Richard Wolf GmbH) and a Microperc 4.85/8 Fr (with the patient supine) with flexible fiberoptics (0.9mm, 120° and 10,000 pixels) (PolyDiagnost GmbH). The study variables were demographic data, stone characteristics, percentage of stone elimination, complications (Clavien-Dindo), surgical time, hospital stay and need for auxiliary procedures.

RESULTS

The patients underwent RIRS (n=12) or microperc (n=8). There were no differences in the demographics or stone characteristics between the 2 groups. The percentage of stone elimination with RIRS and microperc was 91.7% and 87.5% (P=1), respectively. One of the patients who underwent RIRS (8.3%) experienced postoperative fever; one of the patients who underwent microperc (12.5%) experienced postoperative colic pain (both cases were classified as Clavien I). The operative times were similar: 120min (111.2-148.7) and 120 (88.7-167.5) min for RIRS and microperc (P=.8), respectively. None of the patients required a blood transfusion. The hospital stays were also equivalent: 1 day (1-2) and 1.5 days (1-3.5) for RIRS and microperc (P=.33), respectively. Two patients treated with microperc (25%) required auxiliary procedures (simultaneous RIRS and flexible nephroscopy after percutaneous trajectory dilation to treat, in both cases, a significant fragment that had migrated to an inaccessible calyx), and 1 patient in the RIRS group (8.3%) required percutaneous nephrolithotomy due to unfavorable infundibular-calyceal anatomy (P=.54).

CONCLUSIONS

Microperc is a minimally invasive method that is emerging as an effective and safe treatment for intermediate-sized kidney stones. Studies are needed to better evaluate its cost-effectiveness, the need for complementary treatments and its possible complementarity with RIRS when working with patients in the supine position.

Micropercutaneous nephrolithotomy. A new therapeutic option for pediatric renal lithiasis

INTRODUCTION

Micropercutaneous nephrolithotomy is an evolution from the conventional percutaneous surgery in which pyelocaliceal access is obtained through minimum bore holes. Its objective is the complete removal of the calculi, lowering the morbidity associated with larger bore percutaneous tracts.

MATERIAL AND METHODS

We present the case of a micropercutaneous nephrolithotomy performed in a 14-year-old female patient with a 35 mm diameter kidney stone located in the renal pelvis. Surgery was performed in the Galdakao-modified supine Valdivia position. Puncture was done under ultrasound and fluoroscopic guidance. The 4.85 Ch needle of the Microperc(®) set was used, completing the procedure through the 8 Ch working shaft. Lasertripsy was done with the Ho:YAG laser. An indwelling double J stent was placed at the end of the procedure.

RESULTS

Operating time was 170 minutes. Hospital stay was one day. She suffered renal colic after 72 hours, which was resolved with oral analgesic treatment at home (Clavien I). She returned to school on the fifth postoperative day. The double J was removed at 2 weeks. At one month of the surgery, the patient is asymptomatic, a 4mm lower calyx residual stone being observed in the abdominal ultrasound.

CONCLUSION

Micropercutaneous nephrolithotomy is a step forward towards the search for a less invasive kidney stone treatment. It is a safe and effective technique in the pediatric population, and it can be performed in the supine position, even in orthotropic kidneys. Future studies and collaborative works will help to better define its indications, to optimize its technique and to analyze its cost-effectiveness compared with other treatment options.

Micropercutaneous Nephrolithotomy in the Management of Bilateral Renal Stones in a 7-Month-Old Infant: The Youngest Case in the Literature

During infancy, the renal parenchyma and pelvicalyceal system are relatively fragile. Therefore, percutaneous nephrolithotomy for the management of renal stones in this age group is a challenging procedure for urologists. Herein, we present the uneventful management of bilateral renal stones using micropercutaneous nephrolithotomy (microperc) administered to a 7-month-old infant with recurrent urinary tract infections. In this paper, the advantages and disadvantages of the microperc procedure are discussed. As far as we know, our patient is the youngest case in whom the microperc procedure has been performed.

Percutaneous nephrolithotomy versus retrograde intrarenal surgery: a systematic review and meta-analysis

CONTEXT

Recent advances in technology have led to the implementation of mini- and micro-percutaneous nephrolithotomy (PCNL) as well as retrograde intrarenal surgery (RIRS) in the management of kidney stones.

OBJECTIVE

To provide a systematic review and meta-analysis of studies comparing RIRS with PCNL techniques for the treatment of kidney stones.

EVIDENCE ACQUISITION

A systematic literature review was performed in March 2014 using the PubMed, Scopus, and Web of Science databases to identify relevant studies. Article selection proceeded according to the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analysis criteria. A subgroup analysis was performed comparing standard PCNL and minimally invasive percutaneous procedures (MIPPs) including mini-PCNL and micro-PCNL with RIRS, separately.

EVIDENCE SYNTHESIS

Two randomised and eight nonrandomised studies were analysed. PCNL techniques provided a significantly higher stone-free rate (weighted mean difference [WMD]: 2.19; 95% confidence interval [CI], 1.53-3.13; p<0.00001) but also higher complication rates (odds ratio [OR]: 1.61; 95% CI, 1.11-2.35; p<0.01) and a larger postoperative decrease in haemoglobin levels (WMD: 0.87; 95% CI, 0.51-1.22; p<0.00001). In contrast, RIRS led to a shorter hospital stay (WMD: 1.28; 95% CI, 0.79-1.77; p<0.0001). At subgroup analysis, RIRS provided a significantly higher stone-free rate than MIPPs (WMD: 1.70; 95% CI, 1.07-2.70; p=0.03) but less than standard PCNL (OR: 4.32; 95% CI, 1.99-9.37; p=0.0002). Hospital stay was shorter for RIRS compared with both MIPPs (WMD: 1.11; 95% CI, 0.39-1.83; p=0.003) and standard PCNL (WMD: 1.84 d; 95% CI, 0.64-3.04; p=0.003).

CONCLUSIONS

PCNL is associated with higher stone-free rates at the expense of higher complication rates, blood loss, and admission times. Standard PCNL offers stone-free rates superior to those of RIRS, whereas RIRS provides higher stone free rates than MIPPs. Given the added morbidity and lower efficacy of MIPPs, RIRS should be considered standard therapy for stones <2 cm until appropriate randomised studies are performed. When flexible instruments are not available, standard PCNL should be considered due to the lower efficacy of MIPPs.

PATIENT SUMMARY

We searched the literature for studies comparing new minimally invasive techniques for the treatment of kidney stones. The analysis of 10 available studies shows that treatment can be tailored to the patient by balancing the advantages and disadvantages of each technique.

Comparative study of retrograde intrarenal surgery and micropercutaneous nephrolithotomy in the treatment of intermediate-sized kidney stones

OBJECTIVE

Retrograde intrarenal surgery (RIRS) has proven efficacy with minimal morbidity in the treatment of intermediate-sized kidney stones. The aim of this study was to examine the feasibility of micropercutaneous nephrolithotomy (microperc) for this indication and evaluate its results compared with those of RIRS.

MATERIAL AND METHODS

From September to December 2013, we performed a comparative prospective study between RIRS and microperc, with 20 consecutive patients with intermediate-sized (1-3cm) kidney stones. We employed a flexible dual-channel ureteroscope (Cobra, Richard Wolf GmbH) and a Microperc 4.85/8 Fr (with the patient supine) with flexible fiberoptics (0.9mm, 120° and 10,000 pixels) (PolyDiagnost GmbH). The study variables were demographic data, stone characteristics, percentage of stone elimination, complications (Clavien-Dindo), surgical time, hospital stay and need for auxiliary procedures.

RESULTS

The patients underwent RIRS (n=12) or microperc (n=8). There were no differences in the demographics or stone characteristics between the 2 groups. The percentage of stone elimination with RIRS and microperc was 91.7% and 87.5% (P=1), respectively. One of the patients who underwent RIRS (8.3%) experienced postoperative fever; one of the patients who underwent microperc (12.5%) experienced postoperative colic pain (both cases were classified as Clavien I). The operative times were similar: 120min (111.2-148.7) and 120 (88.7-167.5) min for RIRS and microperc (P=.8), respectively. None of the patients required a blood transfusion. The hospital stays were also equivalent: 1 day (1-2) and 1.5 days (1-3.5) for RIRS and microperc (P=.33), respectively. Two patients treated with microperc (25%) required auxiliary procedures (simultaneous RIRS and flexible nephroscopy after percutaneous trajectory dilation to treat, in both cases, a significant fragment that had migrated to an inaccessible calyx), and 1 patient in the RIRS group (8.3%) required percutaneous nephrolithotomy due to unfavorable infundibular-calyceal anatomy (P=.54).

CONCLUSIONS

Microperc is a minimally invasive method that is emerging as an effective and safe treatment for intermediate-sized kidney stones. Studies are needed to better evaluate its cost-effectiveness, the need for complementary treatments and its possible complementarity with RIRS when working with patients in the supine position.

[PCNL: what's changed?]

PCNL is a endourological technique for the treatment of kidney stones disease. It's aim is to achieve the complete clearance via a percutaneous access. This technique, as we know it today, was developed by Johanson and Fernstrom in 1976 who used the technological advances in percutaneous fluoroscopy to get the percutaneous access. Following the application of various sources of energy for the fragmentation of the calculi such as ultrasound energy, there was the worldwide diffusion of PCNL thanks to Alken and Marbergen in Europe, Segura and Clayman in the USA. Despite in the early '80s the PCNL lost the initial impulse in favor of the SWL, in the '90s, it revived a second golden age through the application of emerging technologies such as computed tomography, techniques of obtaining the percutaneous access, flexible instrumentation, laser energy and, more recently, robotic surgery, and virtual reality. All of these contributed to bring the PCNL on the road up of the mini-invasiveness to the latest development of Microperc. The Microperc allows the treatment of stones of 2 cm in diameter also, obtaining the access under ultrasound, fluoroscopic and direct vision guidance. A complete system including micor-optics, laser fiber and irrigation system is then inserted into the same needle with a diameter of 4.85, 8 or 10 Fr The CROES used logistic developments by creating a global network and a multi-center database. The PCNL study, concluded in 2009, has led to the publication of as many as 27 scientific papers on this subject.

Comparison of intrarenal pelvic pressure during micro-percutaneous nephrolithotomy and conventional percutaneous nephrolithotomy

The micro-percutaneous nephrolithotomy (microperc) is a recently introduced percutaneous nephrolithotomy (PNL) technique that is performed through a 4.8 Fr all-seeing needle. We aimed to measure the intrarenal pelvic pressure (IPP) during microperc and compare it with the levels of conventional PNL. A total of 20 patients with 1- to 3-cm renal calculi resistant to shock wave lithotripsy were treated either with microperc (Group-1, n: 10) or conventional PNL (Group-2, n: 10) by the same surgical team. The IPP was measured during different stages (entrance into the collecting system, stone fragmentation, and before termination) of the procedures by an urodynamic machine using the 6 Fr ureteral catheter. All the variables were statistically compared between the two groups. The demographic values of the patients were similar. The operation time and duration of hospitalization were significantly prolonged in conventional PNL group (p = 0.034, p = 0.01, respectively). The mean drop in hematocrit levels was significantly lower in microperc group (3.5 ± 1.5 vs. 1.8 ± 0.8; p = 0.004). The IPP was significantly higher in microperc group during all steps of the procedure. The highest level of the IPP was measured as 30.3 ± 3.9 and 20.1 ± 3.1 mmHg in Group 1 and Group 2, respectively (p < 0.0001). However, the complication and success rates were found comparable. In conclusion, we demonstrate that the level of IPP is significantly increased during microperc compared to conventional PNL. Microperc should be used cautiously in cases with impaired drainage of the collecting system.