Effect of percutaneous nephrolithotripsy on renal function: assessment with quantitative SPECT of (99m)Tc-DMSA renal scintigraphy

Changes in renal volume post Percutaneous nephrolithotomy based on ultrasonography and its correlation with glomerular filtration rate (GFR)

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is considered to be the gold standard management for renal calculi. The purpose of this study is to comprehend the overall alterations in renal volume occurring after PCNL. The changes in the kidney's total volume in individual patients will be examined by ultrasonography pre and postoperatively, and it will be correlated with GFR.

MATERIALS AND METHODS

It was a prospective observational study performed over 70 participants, conducted at the department of Urology of a tertiary care hospital in Eastern India. Each patients were evaluated with pre and post PCNL USG for kidney volume and GFR. The data was statistically evaluated by SPSS software.

RESULTS

The preoperative and post operative calculated mean GFR was 96.030 ± 18.922 ml and 86.681 ± 16.938 ml,volume was 127.258 ± 25.705 and 123,678 ± 26.357 respectively . There was statistically significant decrease in GFR and volume following PCNL. It also shows that patients who underwent single puncture PCNL had significantly less decrease in GFR and kidney volume compared to multiple puncture PCNL. Moreover, the calculated mean change in GFR and volume were significantly less seen in single puncture-one step dilatation and single puncture-serial dilatation as compared to multiple puncture-one step dilatation and multiple puncture-serial dilatation.

CONCLUSION

Our study showed that there was significant changes in the renal volume and GFR following PCNL . So, a sonographic estimation of renal dimensions and GFR calculation after PCNL will help in the prognosis and further follow up of patients. A Single puncture had a better operative outcome and less adverse consequences with respect to GFR, volume change and for renal function as compared to multiple puncture.

Perioperative and long-term results of ultrasonography-guided single- and multiple-tract percutaneous nephrolithotomy for staghorn calculi

BACKGROUND

It is possible that this condition will lead to urosepsis and progressive deterioration of renal function in the absence of surgical intervention. Several recent clinical studies have shown that multi-tract percutaneous nephrolithotomy (M-PCNL) has a similar stone free rate (SFR) as standard percutaneous nephrolithotomy (S-PCNL). As a result, M-PCNL was also recommended as a treatment option for staghorn calculi.

AIM

To examine the perioperative and long-term results of ultrasonography-guided single- and M-PCNL.

METHODS

This was a retrospective cohort study. Between March 2021 and January 2022, the urology department of our hospital selected patients for the treatment of staghorn calculi using percutaneous nephrolithotomy. The primary outcomes were complication rate and SFR, and the characteristics of patients, operative parameters, laboratory measurements were also collected.

RESULTS

In total, 345 patients were enrolled in the study (186 in the S-PCNL group and 159 in the M-PCNL group). The SFR in the M-PCNL group was significantly higher than that in the S-PCNL group (P = 0.033). Moreover, the incidence rates of hydrothorax (P = 0.03) and postoperative infection (P = 0.012) were higher in the M-PCNL group than in the S-PCNL group. Logistic regression analysis demonstrated that post-operative white blood cell count (OR = 2.57, 95%CI: 1.90-3.47, P < 0.001) and stone size (OR = 1.59, 95%CI: 1.27-2.00, P < 0.001) were associated with a higher overall complication rate in the S-PCNL group. Body mass index (OR = 1.22, 95%CI: 1.06-1.40, P = 0.004) and stone size (OR = 1.70, 95%CI: 1.35-2.15, P < 0.001) were associated with increased overall complications in the M-PCNL group.

CONCLUSION

Multiple access tracts can facilitate higher SFR while slightly increasing the incidence of acceptable complications.

The effect of standard percutaneous nephrolithotomy, miniaturized percutaneous nephrolithotomy and retrograde intrarenal surgery on biomarkers of renal injury: a randomized clinical trial

Background

Observational studies on the association of endourological procedures with renal parenchymal damage are lacking. This randomized trial examined the effect of standard percutaneous nephrolithotomy (sPCNL) in comparison with miniaturized-PCNL (mini-PCNL) and retrograde intrarenal surgery (RIRS) for nephrolithiasis treatment on novel biomarkers of renal injury.

Methods

Seventy-five patients were randomized in a 1:1:1 ratio to receive sPCNL, mini-PCNL and RIRS for nephrolithiasis. The ratios of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and interleukin-18 (IL-18) normalized for urinary creatinine (Cr) were calculated from urine samples collected at baseline (2-h preoperatively) and at 2-, 6-, 24- and 48-h postoperatively. Two-way mixed analysis of variance (ANOVA) for repeated measurements was used to evaluate the effects of type of procedure and time on studied biomarkers.

Results

Between baseline and 2-h postoperatively, no significant differences were observed in NGAL/Cr changes between sPCNL [median (interquartile range) 9.46 (4.82-14.9)], mini-PCNL [12.78 (1.69-25.24)] and RIRS [6.42 (2.61-23.90)] (P = .902). Similarly, no between-group differences were observed for KIM-1/Cr (P = .853) and IL-18 (P = .980) at 2 h, and all biomarkers at any time-point postoperatively. Within-groups, significant increases from baseline were noted for NGAL/Cr (sPCNL, P < .001; mini-PCNL, P < .001; RIRS, P = .001), KIM-1/Cr and IL-18/Cr at 2 h; progressively lower increases from baseline were noted in all groups for KIM-1/Cr and IL-18/Cr at 6-, 24- and 48-h postoperatively. As such, a significant effect of time but not of type of procedure was evidenced with two-way mixed ANOVA. No significant between-group differences were observed in acute kidney injury incidence and complications.

Conclusions

The endourological procedures under study are associated with similar patterns of early tubular injury, detected by novel biomarkers, which is largely reduced within 48 h and no changes in glomerular function.

The effect of percutaneous tract dilation technique on renal parenchymal trauma: An experimental in vivo study on a porcine model

Purpose

The purpose of this study was to evaluate renal parenchymal trauma of two-step dilation compared to the conventional Amplatz gradual dilation during percutaneous nephrolithotomy on a porcine model.

Materials and Methods

A nonpapillary percutaneous access tract was established under fluoroscopic guidance in both kidneys of four female pigs. On the right kidney of each pig, gradual dilation was performed using an Amplatz dilator set with a gradual dilation to 30 Fr, whereas on the left, a two-step dilation was utilized using only 16 Fr and 30 Fr dilators. Two of the animals were euthanized immediately after the procedure and the remaining two 1 month later. The pigs that were kept alive underwent a contrast-enhanced computed tomography immediately, 15, and 30 days postoperatively. A dimercaptosuccinic acid (DMSA) scintigraphy and single-photon emission computed tomography-computed tomography (CT) were also performed after the last CT and afterward, the pigs were sacrificed. All kidneys were harvested for pathohistological examination.

Results

The follow-up radiologic imaging showed similar parenchymal damage caused by the compared dilation techniques and an expected reduction in scar size in the later scans. No scar was identified by DMSA in any kidney. Gross and microscopic examinations conducted both on the kidneys that were harvested immediately after the procedure and the ones from the animals that were left to heal, revealed no significant differences in tissue damage, grade of fibrosis, or inflammation depending on the dilation method.

Conclusions

Our study showed no inferior outcomes caused by two-step dilation compared to gradual dilation regarding renal parenchymal damage following a nonpapillary puncture. In fact, postoperative imaging findings suggested a trend toward better healing and less scar tissue when the two-step method was used.

Influencing factors of acute kidney injury following retrograde intrarenal surgery

PURPOSE

To investigate the influencing factors of acute kidney injury (AKI) following retrograde intrarenal surgery (RIRS).

METHODS

The data of patients who underwent RIRS for kidney stones between January 2018 and June 2022 at two tertiary centers were retrospectively analyzed. Demographic data of patients were obtained. According to kidney disease: Improving Global Outcomes (KDIGO) criteria, those with and without AKI were divided into two groups. Preoperative, intraoperative, and postoperative predictive factors of patients were investigated between the groups. In addition, the influencing factors of AKI were examined by multivariate analysis.

RESULTS

This study included 295 (35.7%) women and 532 (64.3%) men. The mean age was 50.03 ± 15.4 years (range 18-89), and mean stone size was 15.5 ± 6.1 mm (range 6-47). Overall, 672 of patients (81.3%) were stone-free after the initial treatment. According to KDIGO, 110 of patients (13.3%) had AKI during the postoperative period. Univariate analysis showed that stone size (P = .003), previous stone surgery (P = .010), renal malformations (P = .017), high operative time (P =  < .001), high preoperative creatinine value (P = .036), intraoperative complications (P = .018), and postoperative urinary tract infection (P = .003) had significant influence on the AKI after RIRS. Multivariate analysis excluded previous stone surgery, high preoperative creatinine value, renal malformations, and intraoperative complications from the logistic regression model, whereas other factors maintained their statistically significant effect on AKI, indicating that they were independent predictors.

CONCLUSIONS

Stone size, operative time, postoperative urinary tract infection, and diabetes mellitus are significant predictors of AKI. During RIRS, urologists should consider the factors that increase the risk of AKI and evaluate the treatment outcomes based on these factors.

Comparison of the effect of miniaturized and standard percutaneous nephrolithotomy on renal function assessed with DMSA scintigraphy

INTRODUCTION AND OBJECTIVES

We aimed to present a clinical study that compares standard and miniaturized percutaneous nephrolithotomy (PNL) effects on kidney function with scintigraphic imaging in primary kidney stone patients.

MATERIALS AND METHODS

One hundred four patients were included in this prospective study between May 2014 and February 2017. Eligible patients were divided into two groups miniaturized PNL (mPNL) and standard PNL (sPNL) with matched-pair analysis (1:1 scenario). Technetium-99m Dimercaptosuccinic Acid cortical scintigraphy imaging was performed before and after the operation.

RESULTS

There were no differences between the two groups in terms of success rate (mPNL (63.5%) vs. sPNL (71.2%), p=0.403), serum creatinine, glomerular filtration rate, split renal functions pre- and postoperatively (p≥0.05). There was no relationship between the type of operation and new scar formation (p=0.780). The rates of serious complication (grades 3 and 4 according to modified Clavien-Dindo Classification) were higher in sPNL (p=0.034). Stone burden, duration of operation, hemoglobin drop, multiple access, blood transfusion, and angioembolization were higher in patients with scarred kidneys (p<0.001, p=0.008, p=0.004, p<0.001, p=0.003, p=0.001, respectively). In multivariate analysis, only multiple access was found statistically significant for predicting new scar formation (p<0.001, OR: 24.28).

CONCLUSIONS

Miniaturized and standard PNL are reliable and successful operations for treating large kidney stones. No significant difference was found between the operation types regarding a decrease in renal function.

Comparison of renal parenchymal trauma after standard, mini and ultra-mini percutaneous tract dilation in porcine models

OBJECTIVE

To evaluate whether reducing tract dilation diameter in PCNL (percutaneous nephrolithotomy) procedures results in minimizing of renal trauma of the percutaneous tract.

METHODS

A percutaneous renal access tract was established bilaterally to 11 pigs. Two pigs were euthanized immediately after the experiment, while nine pigs were sacrificed 1 month later. The percutaneous accesses were dilated up to 30Fr, 22Fr or 12Fr. The animals underwent a contrast-enhanced computer tomography immediately after the procedure and 30 days later. DMSA-scintigraphy with SPECT-CT was also performed. The kidneys of all animals were harvested for histological evaluation. The volume of scar tissue and the percentage of renal volume replaced by scar tissue were calculated.

RESULTS

Immediate post-procedural CT-scans revealed a significant difference in defect diameter among the three modalities. However, the scar volume calculated on CT-images and histopathology showed a significant difference only when 30Fr dilation was compared to 12Fr dilation. The percentage of scar volume was negligible in all cases, but there was still a statistical difference between 30 and 12Fr dilation. Dilation up to 22Fr revealed no statistical differences compared to the other two modalities. DMSA-scintigraphy showed no scar tissue in any case.

CONCLUSION

Dilation up to 30Fr may cause a significantly larger scar tissue on renal parenchyma compared to 12Fr dilation as it was shown on CT-images and microscopic evaluation, but based on the DMSA/SPECT-CT this difference seems to be insignificant to the renal function. The scar tissue caused by 22Fr dilation seemed to have no significant difference from the other modalities.

Meta-Analysis of Laparoscopic Pyelolithotomy versus Percutaneous Nephrolithotomy as a Treatment of Large Kidney Stones

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Comparison of laparoscopic pyelolithotomy and retrograde intrarenal surgery in the management of large renal pelvic stones

BACKGROUND

To compare the clinical outcomes of laparoscopic pyelolithotomy (LP) and retrograde intrarenal surgery (RIRS) in the management of large renal pelvic stones.

PATIENTS AND METHODS

This study included patients who presented with a single renal pelvic stone sized ≥20 mm and who were treated primarily by LP or RIRS. The patients were grouped based on the surgical procedure they underwent. We retrospectively examined and compared the age, the longest axis, and the surface area of the stone, operation time, hospitalization time, complications, and stone-free rates of the two groups.

RESULTS

Of the 156 patients included in the study, 44 had LP, and 112 had RIRS. Patients who received LP (13 males, 31 females) had a median age of 54 (18-79) years, while those who underwent RIRS (46 males, 66 females) had a median age of 54.5 (18-79). Patients who received LP were found to have larger median stone size (30 mm vs 24 mm, P = .003), longer operation time (100 minutes vs 70 minutes, P = .007), lower complication rate (2% vs 8.9%, P = .063), longer median hospital stay (3 days vs 1 day, P < .001) and better stone-free rate at the third month (90.9% vs 67.9%, P < .001).

CONCLUSION

LP is a safe and efficient procedure that could be used as an alternative to RIRS in managing large renal pelvic stones.

Are endourological procedures for nephrolithiasis treatment associated with renal injury? A review of potential mechanisms and novel diagnostic indexes

Nephrolithiasis is one of the most common urological conditions with a huge socio-economic impact. About 50% of recurrent stone-formers have just one lifetime recurrence and >10% of patients present with a high recurrent disease requiring subsequent and sometimes multiple surgical interventions. The advent of new technology has made endourological procedures the pinnacle of stone treatment, including procedures like percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery and miniaturized PCNL procedures. Researchers have primarily focused on comparisons with respect to stone-free rates, procedure parameters and post-operative complications. However, the effect of these three procedures on renal function or indexes of renal injury has not been sufficiently examined. This was only reported in a few studies as a secondary objective with the use of common and not the appropriate and detailed renal parameters. This review presents current literature regarding the use of novel and highly predictive biomarkers for diagnosing acute kidney injury, discusses potential mechanisms through which endourological procedures for renal stone treatment may affect renal function and proposes areas with open questions where future research efforts in the field should focus.

Role of Endourological Procedures (PCNL and URS) on Renal Function: a Systematic Review

PURPOSE OF REVIEW

To present the latest evidence related to the impact of ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) on the renal function.

RECENT FINDINGS

Our review suggests that the overall renal function is not detrimentally affected by endourological interventions (URS, PCNL). This is however influenced by the preoperative renal function, presence of comorbidities such as diabetes and hypertension. For PCNL procedures, tract multiplicity, preoperative UTI, and postoperative bleeding also contribute to a decline in renal function. This review suggests that endourological interventions do not adversely affect renal function and tend to improve it in patients who do not have a poor renal function prior to the procedure. Several factors including poor preoperative renal function, diabetes, hypertension, and multiple percutaneous tracts appear to predispose patients to declining renal function after procedure, and these patients should be counseled for and followed up appropriately.

Postoperative renal functional changes assessed by 99mTc-DTPA scintigraphy and predictive factors after miniaturized percutaneous nephrolithotomy and retrograde intrarenal surgery: An observational 1-year follow-up study

Purpose

We evaluated the comparative effect of miniaturized percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) on perioperative kidney function by use of diethylenetriamine penta-acetic acid (^99mTc-DTPA) scintigraphy and identified significant predictors associated with deterioration or amelioration of renal function after surgery.

Materials and Methods

All 70 patients who underwent mini-PCNL or RIRS between 2012 and 2016 were monitored by ^99mTc-DTPA scintigraphy preoperatively. Patients with abnormal renal function were monitored from 3 to 12 months postoperatively. Logistic regression analyses were conducted to estimate the predictors of aggravated renal dysfunction and improvement.

Results

The difference in preoperative renal function between the contralateral and the operative side was >10% in 57 patients (81.4%). Among those in the group with abnormal renal function, 40 (70.2%), 10 (17.5%), and 7 (12.3%) patients showed stability, deterioration, and improvement in renal function at postoperative year 1, respectively. Functional changes did not differ according to the type of surgery. A high level of serum creatinine preoperatively (p=0.060) and a history of previous stone procedures (p=0.051) showed borderline significance for prediction of deterioration in renal function.

Conclusions

RIRS and mini-PCNL had similar effects and favorable outcomes on renal function during a 1-year follow-up period. High baseline serum creatinine levels and a history of procedures warrant careful attention.

Kidney volume loss following percutaneous nephrolithotomy utilizing 3D planimetry

Parenchymal damage and renal function impairment following percutaneous nephrolithotomy (PCNL) are of great concern. This study aims to evaluate post-operative changes in renal volume after PCNL. We retrospectively analyzed baseline and post-PCNL CT images from 25 eligible patients from a single tertiary care center. All CT imaging was reviewed using 3D planimetry software (3D Splicer^®, Version 4.0). Segmentation was utilized to obtain total kidney volume (TKV), total kidney surface area, total stone surface area, and total stone volume. Wilcoxon signed-rank test was used for pair analysis, and univariate and multivariable analyses were performed to examine the relationships between clinical and planimetry data and renal volume loss. The median age of the cohort was 62 years, with the majority of the patients having undergone a previous PCNL (52.0%). The median TKV (cm³) pre- and post-PCNL were 225.25 and 178.09, respectively (p = 0.001), with average volume decline of 21%. While there was a statistically significant kidney volume loss in our cohort, there was no difference between pre- and post-operative serum creatinine (mg/dL): 0.93 and 0.94 (p = 0.696), respectively. Multivariable analysis showed a higher TKV loss with a larger kidney stone surface area (OR 1.002, CI 1-1.003, p = 0.035), while younger age was found to be protective (OR 0.791, CI 0.587-0.925 p = 0.028). Patients with previous history of PCNL experiences a more pronounced TKV loss (53.77 cm³, p = 0.031), as compared to PCNL naïve patients (13.05 cm³, p = 0.224). Our study consistently revealed a decrease in TKV following PCNL. Furthermore, among patients with larger stone surface areas, and history of previous PCNL there was an increase in the loss of TKV after the procedure.

The efficacy of flexible ureteroscopy lithotripsy and miniaturized percutaneous nephrolithotomy for the treatment of renal and proximal ureteral calculi of ≤2 cm: A retrospective study

To assess the clinical effect of miniaturized percutaneous nephrolithotomy (MPCNL) and flexible ureteroscopy lithotripsy (FURL) for the treatment of renal and proximal ureteral calculi of ≤2 cm.A retrospective analysis was carried out on clinical data of 106 patients with kidney or upper urethral calculi. Among these patients, 58 underwent the MPCNL, and 48 received FURL. Stone-free rates, operating time, blood loss, hemoglobin drop, length of hospital stay, complications, and renal damage indexes were compared.The stone removal rates of the FURL and MPCNL groups were 81.25% versus 87.93% (p > .05). Although operating time was significantly shorter in the MPCNL group, hospital stays were significantly shorter in the FURL group. In addition, pooled analysis showed that mean estimated blood loss was significantly higher in the PCNL group but the hemoglobin decline of the FURL group and PCNL group had no significant difference. The PCNL group had no significant difference in complications compared to the FURL group. Differences on the creatinine levels and urea nitrogen levels before the operation and after the operation were not statistically significant.FURL is an effective method for treating renal stone. FURL not only had a similar stone-free rate as compared to MPCNL but also was associated with less blood loss and more favorable recovery time. However, FURL had a longer operative time.

A prospective study evaluating impact on renal function following percutaneous nephrolithotomy using Tc99m ethylenedicysteine renal scan: Does multiplicity of access tracts play a role?

Purpose

A prospective study evaluating impact of percutaneous nephrolithotomy (PCNL) on renal function following PCNL using ethylenedicysteine (EC) renal scan. Does multiplicity of access tracts play a role?

Materials and Methods

A prospective observational study was done and patients undergoing PCNL for renal calculi at our urology department were selected. Renal Tc99m EC scan was done pre-surgery and at 3 months follow-up. An assessment was done on decline in glomerular filtration rate (GFR) in postoperative period based on number of access tracts required.

Results

A total of 110 patients were enrolled in the study. The total number of punctures was 170 with 141 being supra-costal puncture and 29 infra-costal. The total number of single punctures were 60 and classified as Group I whereas patients with double puncture and triple puncture (40 and 10 patients, respectively) were classified as Group II. Mean postoperative split renal function (in Tc99m EC scans) of patients of Group I (40.93±19.62%) was found to be higher than that of Group II (32.82±16.98%). Mean change (decline) in GFR for single, double and triple tracts were 2.68 mL/min, 3.80 mL/min, and 4.2 mL/min, respectively.

Conclusions

PCNL used for stone removal can improve renal function by eradicating obstruction; however, this procedure may itself negatively impact the functions of the targeted kidney. Our study showed post PCNL decrease in GFR which worsens with an increasing number of accesses.

Percutaneous nephrolithotomy: complications and how to deal with them

Percutaneous nephrolithotomy is a common surgical treatment for large and complex stones within the intrarenal collecting system. A wide variety of complications can result from this procedure, including bleeding, injury to surrounding structures, infection, positioning-related injuries, thromboembolic disease, and even death. Knowledge of the different types of complications can be useful in order to prevent, diagnose, and treat these problems if they occur. This review describes the diversity of complications with the goal of improving their avoidance and treatment.

Percutaneous Nephrolithotomy for Stones in Solitary Kidney: Evidence From a Systematic Review

Stones in solitary kidney represent a management dilemma for the endourologist. The advantage of bilateral fully functioning kidneys is not present. Therefore, any insult to either the solitary kidney itself or drainage system can lead to significant morbidity. Key clinical objectives include maximum preservation of existing renal function, high stone clearance, and minimizing post-procedure complications. To date, there exists no Level 1 evidence on this subject. This systematic review serves to evaluate the safety and efficacy of percutaneous nephrolithomy for patients (adults only) with stones in a solitary kidney.

Estimation of Split Renal Function With 99mTc-DMSA SPECT: Comparison Between 3D Volumetric Assessment and 2D Coronal Projection Imaging

OBJECTIVE

Split renal function (SRF) can be estimated with ^99mTc-labeled dimercaptosuccinic acid (DMSA) SPECT cortical renal scintigraphy on either 2D projected images or 3D images. The purpose of this study was to determine whether there is a significant difference between SRF values calculated with the 2D method and those calculated with the 3D method.

MATERIALS AND METHODS

This retrospective study was performed with ^99mTc-DMSA SPECT images of 316 patients (age range, 1-26 years). All images were reconstructed by filtered back projection. An automated computational method was developed to estimate SRF using both 2D projection images and direct 3D images. A paired t test was used to evaluate the difference between SRFs determined with the two methods and the association between the magnitude of the differences and kidney size, patient age, and SRF.

RESULTS

There was strong correlation between SRFs estimated with the 2D and 3D methods (r = 0.94, p < 0.001). There was small significant difference (0.14% ± 0.86%, p = 0.003) in SRFs obtained with the two methods. The difference was clinically negligible and independent of renal length (p = 0.698), volume (p = 0.297), and patient age (p = 0.768) but was associated with SRF (p = 0.018).

CONCLUSION

For determination of split renal function, ^99mTc-DMSA SPECT renal scintigraphy 2D coronal projection images perform as well as and are simpler to analyze than 3D images.

Computing quantitative indicators of structural renal damage in pediatric DMSA scans

OBJECTIVES

The proposal and implementation of a computational framework for the quantification of structural renal damage from ^99mTc-dimercaptosuccinic acid (DMSA) scans. The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner.

MATERIALS AND METHODS

From a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan.

RESULTS

A fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%).

CONCLUSIONS

The proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

Comparison of safety and efficacy of laparoscopic pyelolithotomy versus percutaneous nephrolithotomy in patients with large renal pelvic stones: a meta-analysis

To compare percutaneous nephrolithotomy (PCNL) and laparoscopic pyelolithotomy (LP) for surgical management for large (>2 cm) renal stones. We searched MEDLINE, Cochrane, and EMBASE databases until March 11, 2015, using the following search terms: renalpelvic stone, percutaneous nephrolithotomy, laparoscopic pyelolithotomy. Randomized controlled and prospective and retrospective two-armed studies were included. Sensitivity analysis and assessment of the quality of the included studies and publication bias were performed. Nine studies were included in the study with a patient population of 622. The studies were homogeneous with respect to the primary end point of stone-free rate, but were heterogeneous with respect to operation time, length of hospital stay, and blood loss. A higher percentage of patients who received LP remained stone-free following surgery compared with patients who were treated with PCNL (p=0.001). However, the mean operation time was longer for patients with LP than for those treated with PCNL (p=0.002). There was no difference between procedures with regard to length of hospital stay or blood loss (p≥0.071). Sensitivity and quality analysis indicated that the data are reliable and the included studies are of good quality. No publication bias was observed. The study suggests that both procedures are effective and safe for removing large renal stones. However, LP may be more efficacious than PCNL in treating large kidney stones.

The management of large staghorn renal stones by percutaneous versus laparoscopic versus open nephrolithotomy: a comparative analysis of clinical efficacy and functional outcome

The objective of this study was to analyze the outcome of percutaneous nephrolithotomy (PCNL), laparoscopic and open anatrophic nephrolithotomy (AN) for management of patients with large staghorn renal stones. We analyzed the peri-operative parameters, overall treatment costs and changes in the function of the affected kidney on technetium-99 dimercaptosuccinic acid renal scintigraphy, done before the operation and before the final follow-up visit, in 45 adults who underwent PCNL (n = 16) versus laparoscopic (n = 15) versus open (n = 14) AN for large staghorn renal stones. All three groups had statistically similar preoperative characteristics, including the function of the operated kidney on renal scan. On the discharge day, the PCNL group had the lowest stone-free rate (43.75 %) compared to the laparoscopic (80 %) and open AN groups (92.85 %) (P = 0.009). After a mean follow-up period of 12.1 months, the decrease in the function of the operated kidney was greatest in the open AN group (-8.66 ± 4.97) compared to the laparoscopic AN (-6.04 ± 6.52) and PCNL group (-2.12 ± 2.77) (P = 0.003). The need for ancillary procedures to manage residual stones was greatest in the PCNL group and lowest in the open AN group. A similar trend was seen in overall treatment costs (P < 0.001). For management of large staghorn renal stones, the more invasive the procedure, the higher the one-session stone-free rate and the lower the need for ancillary procedures; however, greater renal functional loss can be anticipated. The need for ancillary procedures is a major determining factor in the overall cost of treatment, which was highest in the PCNL group.

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.

Effect of urinary stone disease and its treatment on renal function

Urolithiasis is a common disease that affects urinary tract in all age groups. Both in adults and in children, stone size, location, renal anatomy, and other factors, can influence the success of treatment modalities. Recently, there has been a great advancement in technology for minimally invasive management of urinary stones. The epoch of open treatment modalities has passed and currently there are much less invasive treatment approaches, such as percutaneous nephrolithotomy, ureteroscopy, shockwave lithotripsy, and retrograde internal Surgery. Furthermore, advancement in imaging technics ensures substantial knowledge that permit physician to decide the most convenient treatment method for the patient. Thus, effective and rapid treatment of urinary tract stones is substantial for the preservation of the renal function. In this review, the effects of the treatment options for urinary stones on renal function have been reviewed.

Review on renal recovery after anatrophic nephrolithotomy: Are we really healing our patients?

The main goals for urinary stone treatment are to preserve renal function, reduce or avoid complications related to calculi, and to render the patient free of calculi as soon as possible. Anatrophic nephrolithotomy (ANL) is a valid and useful alternative for conventional staghorn calculi excision. Although excellent stone free rates can be achieved with ANL there are some drawbacks that may be of concern. Morbidity related to intraoperative and postoperative complications is one of them. Another, great concern is the possibility of reduction on renal function related to the procedure itself. This may be related to nephron injury during nephrotomy and parenchymal closure or to ischemic injury. In this review we assess functional results after anatrophic nephrolithotomy.

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.

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.

Assessment of the effects of access count in percutaneous nephrolithotomy on renal functions by technetium-99m-dimercaptosuccinic Acid scintigraphy

Objective. To determine the effects of percutaneous nephrolithotomy on renal functions by using DMSA scintigraphy while considering access counts. Material and Methods. A total of 37 patients who had undergone percutaneous nephrolithotomy were included. Preoperative DMSA scans were performed a day before the surgery, whereas postoperative scans were randomized by evaluating them before (n = 25) and after (n = 12) the 6th postoperative month. Twenty-six of 37 cases underwent percutaneous nephrolithotomy with a single access site and 11 with multiple access sites. Results. There were no significant changes of total renal functions in the whole study group (P = 0.054). In the single access group, total functions were significantly elevated (P = 0.03) In the multiple access group, while treated site functions were significantly decreased (P = 0.01), total functions did not change significantly (P = 0.42). There was an insignificant decrease in those evaluated before the 6th postoperative month (P = 0.27) and an insignificant increase in the others (P = 0.11). Conclusion. We could not find a superiority of single access over multiple accesses. There is a temporary functional loss in the treated site.

Laparoscopic anatrophic nephrolithotomy for management of complete staghorn renal stone: clinical efficacy and intermediate-term functional outcome

PURPOSE

To report the clinical efficacy and intermediate-term functional outcome after laparoscopic anatrophic nephrolithotomy (LAN) as an alternative treatment modality for complete staghorn renal stone.

PATIENTS AND METHODS

The demographic and perioperative parameters as well as the intermediate outcome of 10 adults (9 men) who underwent transperitoneal LAN for complete staghorn renal stone were analyzed. Functional imaging studies consisted of intravenous urography (IVU) and technetium-99 dimercaptosuccinic acid scintigraphy (99Tc-DMSA) renal scan done before the operation and at the last follow-up visit.

RESULTS

Mean age of patients was 48.7 years (range 37-64 years). Mean stone size was 67.3 mm (50-90 mm). Mean operative time was 192 minutes (110-240 min), and mean warm ischemia time was 32.8 minutes (15-40 min). A few hours after laparoscopy, one patient underwent splenectomy because of significant hemorrhage from a splenic laceration (grade IIIb complication). During the follow-up period early after the operation, we detected an 8-mm lower caliceal stone and a 25-mm midcaliceal stone in one patient each (stone-free rate: 80%). After a mean follow-up of 11.9 months (6-19 mos), 85.5% of corresponding renal unit function was preserved; however, there was a significant mean decrease in 99Tc-DMSA uptake from 48.4%±8.83 before surgery to 41.4%±13.98 afterward (-7%±6.53; P=0.008). Nevertheless, renal units were completely functional at follow-up IVU with a significant improvement in obstruction in all patients.

CONCLUSION

LAN is an alternative minimally invasive approach for one-session management of patients with complete staghorn renal stone. It offers an acceptable rate of stone clearance and operative complications but does incur a minimal loss of function in the affected kidney.

Impact of stone disease: chronic kidney disease and quality of life

This article reviews the impact of stone disease on chronic kidney disease and renal function; evaluating the natural progression of disease as well as the impact of surgical interventions. The impact of stone disease, medical therapy, and surgical therapy for stones on quality of life is discussed.

Analysis of changes in the glomerular filtration rate as measured by the cockroft-gault formula in the early period after percutaneous nephrolithotomy

Purpose

We aimed to analyze the changes in kidney function during the postoperative early period caused by the application of percutaneous nephrolithotomy (PNL), which is commonly used in kidney stone surgery.

Materials and Methods

PNL was performed in 80 patients (48 men, 32 women) with kidney stones. The mean age of the patients was 43.71 years (range, 18 to 71 years). Preoperative and postoperative values for stone size, glomerular filtration rate (GFR), serum creatinine, urea, electrolytes (Na, K, Cl), and Hb were compared in 80 patients in whom PNL surgery was performed. The formula of Cockroft-Gault was used to calculate the GFR during the early postoperative period (72 to 96 hours).

Results

Statistically significant decreases after PNL were observed in average stone size (preoperative, 627.75±375.10 mm²; postoperative, 81.70±16.15 mm²), serum urea (preoperative, 38.40±17.26 mg/dl; postoperative, 33.28±16.98 mg/dl), and creatinine (preoperative, 1.03±0.53 mg/dl; postoperative, 0.97±0.55 mg/dl) and an increase was observed in GFR (preoperative, 104.30±37.30 ml/min; postoperative, 112.38±40.1 ml/min). No changes were detected in the serum electrolyte values (Na, K, Cl). Multiple access, operation time, and type of lithotripter did not have any significant effects on the change in the GFR.

Conclusions

In light of our results, PNL for kidney stone operations appears to be a reliable and efficient method that provides recovery of kidney functions in the early post-operative period by increasing the GFR and with high stone-free rates.

Long-term outcomes of percutaneous nephrolithotomy in 177 patients with chronic kidney disease: a single center experience

PURPOSE

We evaluated the long-term outcomes of percutaneous nephrolithotomy in patients with chronic kidney disease.

MATERIALS AND METHODS

Data on 1,904 patients who underwent percutaneous nephrolithotomy between 2002 and 2011 were retrospectively collected. The estimated glomerular filtration rate for each patient was retrospectively calculated using a 4-variable modification of diet in renal disease equation. Patients were staged for chronic kidney disease by National Kidney Foundation guidelines.

RESULTS

A total of 242 patients (12.7%) had a preoperative glomerular filtration rate of less than 60 ml per minute/1.73 m(2). Those monitored a minimum of 1 year were included in analysis. The study included 177 patients with a mean ± SD age of 54.3 ± 12.1 years. Perioperative and postoperative complications were noted in 15.2% of patients. At a mean followup of 43.4 ± 22.7 months renal function in 29.4% of patients had improved but it remained the same or deteriorated in 54.2% and 16.4%, respectively. On multivariate regression analysis diabetes and preoperative or postoperative complications predicted renal function. The stone-free rate 3 months postoperatively was 80.2% (142 of 177 cases). Stones recurred during long-term followup in 36 of these patients (25.3%). Spontaneous stone passage was detected in 12 of the 35 patients (34.2%) with residual stones but 8 (22.8%) with residual stones experienced an increase in stone size.

CONCLUSIONS

At long-term followup renal function was maintained or improved in greater than 80% of patients with chronic kidney disease who underwent percutaneous nephrolithotomy. Stones recurred or residual stones grew in approximately 25% of these patients.

Retrograde intrarenal surgery versus percutaneous nephrolithotomy in the management of lower-pole renal stones with a diameter of 15 to 20 mm

PURPOSE

To compare the outcomes of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) for 15 to 20 mm lower-pole (LP) renal calculi by evaluating stone-free rates and associated complications.

PATIENTS AND METHODS

The records of 79 patients who underwent either PCNL (n=42) or RIRS (n=37) by standard techniques for 15 to 20 mm LP renal calculi were reviewed retrospectively.

RESULTS

In the PCNL group, the stone-free rate was 92.8% (39/42 patients); this rate increased to 97.6% after a second intervention (shockwave lithotripsy in one and RIRS in one). After a single RIRS procedure, 33 of 37 (89.2%) patients were completely stone free. Two patients needed an additional procedure (rigid ureteroscopy in one and RIRS in one), after which they were all completely stone free, resulting in an overall success rate of 94.6%. Two patients had asymptomatic residual fragments <7 mm in the LP of the kidney, and these patients had been followed with ultrasonography of the kidney. For complications, there were minimal differences in both procedures, except for hemorrhage (necessitated transfusion) in three patients who were treated with PCNL. The overall stone-free rates and complication rates for PCNL were higher, but the differences were not statistically significant. Operative time was significantly longer in the RIRS group, and postoperative hospital stay was significantly longer in PCNL group.

CONCLUSION

PCNL and RIRS are safe and effective methods for medium-sized LP calculi. For selected patients, RIRS may represent an alternative therapy to PCNL, with acceptable efficacy and low morbidity.

Renal parenchymal damage after percutaneous nephrolithotomy with one-stage tract dilation technique: a randomized clinical trial

PURPOSE

To compare the effects of one-stage vs gradual dilation techniques during percutaneous nephrolithotomy (PCNL) on postoperative renal scar formation and overall renal function.

PATIENTS AND METHODS

Of 152 adult patients who underwent surgery during the study period, 48 were randomized into two groups. In group 1 (n=19), gradual tract dilation with Alken metallic dilators was used, and in group 2 (n=29), one-stage tract dilation was used. We compared patient demographics, intraoperative and preoperative parameters, postoperative overall renal function, and renal scar formation on the target renal pole.

RESULTS

Access time (P=0.001; 95% confidence interval [CI]: 3.19-6.30) and radiation exposure during access (P=0.03; 95% CI: 0.03-0.66) were significantly shorter in group 2. In group 1, the decrease in mean technetium-99m dimercaptosuccinic acid (99m-Tc DMSA) uptake from 44.1±20.1% to 43.4±19.6% 4 weeks postoperatively (-0.7%±0.5%; P=0.27; 95% CI: -0.56-1.93) was not significant. In group 2, however, there was a significant decrease in post-PCNL 99m-Tc DMSA uptake 2 (-2.4±0.3%, from 50.1±13.5% to 47.7±13.8%; P=0.001; 95% CI: 1.13-3.66). Four weeks after surgery, new scar formation or progression of the preoperative scar at the site of access were seen in 14 of 29 (48.3%) patients who were treated with one-stage dilation whereas only 2 of 19 (11.0%) patients who were treated with gradual dilation developed new scarring at the access site (P=0.007).

CONCLUSION

Although the one-stage tract dilation technique reduced radiation exposure and access time, in the short term, it may cause more parenchymal damage than the gradual dilation technique.

Flexible ureterorenoscopy and holmium laser lithotripsy for the management of renal stone burdens that measure 2 to 3 cm: a multi-institutional experience

BACKGROUND AND PURPOSE

Percutaneous nephrostolithotomy (PCNL) is the current standard of care for management of large renal stones (>2 cm). Recent studies have evaluated flexible ureterorenoscopy (URS)/holmium laser lithotripsy as an alternative treatment for patients with contraindications to or preference against PCNL. Stones in an intermediate size range (2-3 cm) may be most amenable to URS/laser lithotripsy as definitive treatment in a single stage. We report a multi-institutional series of URS/laser lithotripsy for renal stone burdens that measure 2 to 3 cm.

PATIENTS AND METHODS

Patients who underwent URS/holmium laser lithotripsy for renal stones that measured 2 to 3 cm were identified retrospectively at three tertiary care centers. Demographic information, disease characteristics, and perioperative and postoperative data were gathered. Patients with renal stone burdens of 2 to 3 cm who were treated by URS/laser lithotripsy and had at least one postoperative visit and imaging study were included. Stone clearance was evaluated using 0-2 mm and <4 mm residual stone burden on postoperative imaging.

RESULTS

One hundred and twenty patients underwent URS/holmium laser lithotripsy for renal stones of 2 to 3 cm. Mean stone burden was 2.4 cm, and mean body mass index was 29.3 kg/m². Indications for URS/laser lithotripsy vs PCNL included patient preference (57), technical or anatomic factors (24), patient comorbidities (17), failed shockwave lithotripsy (9), patient body habitus (3), solitary kidney (3), chronic renal insufficiency (3), and strict anticoagulation (2). Thirty-one (26%) patients had stent placement preprocedure, and 94 (78%) patients underwent outpatient surgery. A ureteral access sheath was used in 67%. One hundred and one (84%) patients underwent single-stage procedures. There was one intraoperative complication (ureteral perforation), and there were eight minor postoperative complications (6.7%). The reoperation rate through the mean 18-month follow-up was 3/120 or 2.5%. Seventy-six (63%) patients had residual stone burden of 0 to 2 mm, and 100 (83%) patients had residual burden of <4 mm.

CONCLUSIONS

We demonstrate that single-stage URS/holmium laser lithotripsy is effective for management of renal stones that measure 2 to 3 cm through intermediate follow-up. Staged procedures can be used selectively for technical reasons or disease factors. Although PCNL achieves superior stone clearance overall, URS/laser lithotripsy is a viable treatment option for selected patients.

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.

Long-term results of percutaneous nephrolithotomy for treatment of staghorn stones

OBJECTIVE

• To study long-term results of percutaneous nephrolithotomy (PNL) for treatment of staghorn stones.

PATIENTS AND METHODS

• The records of patients who underwent PNL for staghorn stones between January 1998 and January 2008 were retrospectively reviewed. • Patients who completed follow-up for one year or more were included. Follow-up with KUB and renal ultrasonography were performed every 3-6 months. • Renal radioisotopic scan was performed for patients who had already undergone this study before doing PNL.

RESULTS

• The study included 122 patients (69 male and 53 female) with mean age 47.6 ± 14.5 years (5-74). They underwent 126 PNL. • Perioperative complications were encountered in 28 procedures (22%). The mean period of follow-up was 3.5 ± 2.3 years (1-11.3). Among 71 stone-free kidneys, 18 (25%) developed stone recurrence. Of 55 kidneys with residuals at the start of follow-up, 36 (65%) showed growth of these residuals. • Preoperative and postoperative renograms were performed for 71 patients. • At the last follow-up, differential GFR was stable in 53 (74.5%), improved in 12 (17%) and deteriorated in 6 (8.5%). Among patients with deteriorated renal function, 3 had undergone embolization to control severe bleeding, one developed secondary UPJO, and one had recurrent stone obstructing the kidney.

CONCLUSION

• Long-term functional results of PNL for staghorn stones are satisfactory as 91.5% of kidneys showed stable or improved GFR. Long-term follow-up is mandatory especially for patients with residual stones.

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.

A prospective, randomized trial of management for asymptomatic lower pole calculi

PURPOSE

We determined the natural course and compared the deleterious effects in kidneys of shock wave lithotripsy, percutaneous nephrolithotomy and observation for asymptomatic lower caliceal stones.

MATERIALS AND METHODS

Between April 2007 and August 2008 patients with asymptomatic lower caliceal calculi were enrolled in the study. To assess stone status noncontrast abdominal helical computerized tomography was done 3 and 12 months after intervention. All patients were evaluated by dimercapto-succinic acid renal scintigraphy 6 weeks and 12 months after intervention.

RESULTS

A total of 94 patients were prospectively randomized to percutaneous nephrolithotomy (31), shock wave lithotripsy (31) and observation (32). Mean +/- SD followup was 19.3 +/- 5 months (range 12 to 29). In the percutaneous nephrolithotomy group all patients were stone-free at month 12. Scintigraphy revealed a scar in 1 patient (3.2%) on month 3 followup imaging. In the shock wave lithotripsy group the stone-free rate was 54.8%. Scintigraphy revealed scarring in 5 patients (16.1%). In the observation group 7 patients (18.7%) required intervention during followup. Median time to intervention was 22.5 +/- 3.7 months (range 18 to 26). One patient (3.1%) had spontaneous stone passage. Scintigraphy did not reveal scarring in any patient.

CONCLUSIONS

Stone related events were noted in more than 20% of patients with asymptomatic lower caliceal stones observed expectantly. To manage lower caliceal stones percutaneous nephrolithotomy has a significantly higher stone-free rate with less renal scarring than shock wave lithotripsy. Thus, patients with asymptomatic lower caliceal stones must be informed in detail about all management options, especially focusing on percutaneous nephrolithotomy with its outstanding outcome.