Critical causes in severe bleeding requiring angioembolization after percutaneous nephrolithotomy

Analysis of factors affecting intraoperative hemorrhage during percutaneous nephrolithotomy and establishment of nomogram model

Intraoperative hemorrhage is an important factor affecting intraoperative safety and postoperative patient recovery in percutaneous nephrolithotomy (PCNL). This study aimed to identify the factors that influence intraoperative hemorrhage during PCNL and develop a predictive nomogram model based on these factors.A total of 118 patients who underwent PCNL at the Department of Urology, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University from January 2021 to September 2023 was included in this study. The patients were divided into a hemorrhage group (58 cases) and a control group (60 cases) based on the decrease in hemoglobin levels after surgery. The clinical data of all patients were collected, and both univariate analysis and multivariate logistic regression analysis were conducted to identify the independent risk factors for intraoperative hemorrhage during PCNL. The independent risk factors were used to construct a nomogram model using R software. Additionally, receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA) were utilized to evaluate the model.Multivariate logistic regression analysis revealed that diabetes, long operation time and low psoas muscle mass index (PMI) were independent risk factors for intraoperative hemorrhage during PCNL (P < 0.05). A nomogram model was developed incorporating these factors, and the areas under the ROC curve (AUCs) in the training set and validation set were 0.740 (95% CI: 0.637-0.843) and 0.742 (95% CI: 0.554-0.931), respectively. The calibration curve and Hosmer-Lemeshow test (P = 0.719) of the model proved that the model was well fitted and calibrated. The results of the DCA showed that the model had high value for clinical application.Diabetes, long operation time and low PMI were found to be independent risk factors for intraoperative hemorrhage during PCNL. The nomogram model based on these factors can be used to predict the risk of intraoperative hemorrhage, which is beneficial for perioperative intervention in high-risk groups to improve the safety of surgery and reduce the incidence of postoperative complications.

Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective

This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery.

Methods

A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above.

Results

The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples.

Conclusion

This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

Predictive factors of delayed bleeding after percutaneous nephrolithotomy requiring angioembolization

Objectives

To investigate the predictive factors of delayed post-percutaneous nephrolithotomy (PCNL) haemorrhage because of arteriovenous fistula (AVF) or pseudoaneurysm (PA) and compare the factors between AVF and PA.

Patients and methods

This is a case-control study with a case-to-control ratio of 1:3. Out of 5077 patients who underwent PCNL from April 2015 to April 2018 in three different teaching hospitals, 113 had post-PCNL haemorrhages because of AVF and/or PA. Seventy-two patients met the inclusion criteria and entered the study as cases, while 216 patients without any postoperative complications were selected as controls.

Results

Of all 72 studied patients with complications after PCNL, 35 (48.6%) had AVF, and the rest had PA. The regression model revealed that a history of diabetes (odds ratio [OR]: 2.799, 95% confidence interval [CI]: 1.392-5.630, p-value = 0.004) and renal anomalies (OR: 2.929, 95% CI: 1.108-7.744, p-value = 0.03) were associated with developing delayed post-PCNL haemorrhage. However, no differences were seen between AVF and PA regarding selected variables (p-value > 0.05).

Conclusion

History of diabetes and renal anomalies were predictive factors for delayed post-PCNL haemorrhage, but no predictive factors were found to differentiate PA and AVF from one another.

Application of Bipolar Cauterization During Standard Percutaneous Nephrolithotomy

Introduction: We aimed to evaluate the efficacy of bipolar cauterization for tract site bleeding during standard percutaneous nephrolithotomy (PCNL). Methods and Materials: We defined tract site bleeding as when the visual field across the parenchymal tract starts to bleed while the sheath of a balloon dilator is being withdrawn just before the operation is completed. Among 181 patients, 90 patients showed no significant bleeding, and 91 patients required further procedures to resolve tract site bleeding. In cases of unresolved tract site bleeding, either nephrostomy placement (n = 60) or cauterization (n = 31) was performed. The outcomes of three groups (no procedure group, nephrostomy group and cauterization group) were compared. Results: The median decrease in hemoglobin at 2-hour intervals postoperatively was -1.75, -1.0, and -0.2 in the nephrostomy, cauterization, and no procedure groups, respectively (P < .001). There were 25 patients (41.7%) who received transfusions in the nephrostomy group, whereas only 1 patient (3.2%) received a transfusion in the cauterization group (P < .001). Conclusion: The bipolar cauterization of bleeding points at the end of PCNL could efficiently decrease tract site bleeding and reduce the need for transfusion. Clinical Research Information Service (https://cris.nih.go.kr/cris; No. KCT0008303).

Supine Versus Prone Percutaneous Nephrolithotomy (PCNL): A Single Surgeon's Experience

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is one of the greatest advances in the field of urology and has been considered the gold standard in the treatment of renal calculi of more than 2 cm in size. While both the supine and prone positions offer their unique advantages, it is still being debated which position offers the most in terms of surgical outcomes. We have evaluated the two approaches in terms of operative time, success rate, stone clearance rate, safety, and complications.

METHODS

This prospective cohort study was done in the urology department of a tertiary care center in South India between January 2018 and October 2020. A total of 166 patients, with 83 in supine and 83 in prone positions, were included in the study.

RESULTS

Both groups were matched in terms of age, body mass index, stone size and location, co-morbidities, medications taken, presence of diverticular stone, history of surgery, and baseline creatinine level. Mean operative time and pain scores were noted to be less in supine position as compared to prone. Ease of puncture was superior in supine position. Stone residue was noted to be higher in supine PCNL as well.

CONCLUSION

Supine PCNLs are preferred in high-risk patients while the prone position is preferred in bilateral PCNLs, complex anatomy, or larger stone burden.

Superselective renal arterial embolization for severe postpercutaneous nephrolithotomy haemorrhage: clinical characteristics and risk factors for initial failure

OBJECTIVE

To identify the clinical characteristics of patients who underwent superselective renal arterial embolization (SRAE) after percutaneous nephrolithotomy (PCNL) and to explore the risk factors for failed initial SRAE after PCNL.

MATERIALS AND METHODS

Patients who underwent SRAE for severe haemorrhage following PCNL between January 2014 and December 2020 were included in the study. The clinical data of those patients and the parameters and characteristics of the perioperative PCNL and SRAE procedures were collected and analysed.

RESULTS

A total of 243 patients were included in this study. A total of 139 patients (57.2%) had a pseudoaneurysm, 25 (10.3%) had an arteriovenous fistula, 50 (20.6%) patients had both a pseudoaneurysm and an arteriovenous fistula, and 29 (11.9%) had an arterial laceration. In 177 patients with single percutaneous access, 125 (70.6%) patients exhibited nontract haemorrhage, and 55 (31.1%) patients exhibited multiple bleeding sites. In 66 patients with multiple percutaneous access, 44 (66.7%) patients exhibited nontract haemorrhage, and 32 (48.5%) patients exhibited multiple bleeding sites. The decrease in Hb before SRAE was 41.4 ± 19.8 g/L. The mean time between PCNL surgery and initial SRAE was 6.4 ± 4.9 days. Serum creatinine was increased after the SRAE procedure. Initial SRAE was successful in 229 (94.2%) patients and failed in 14 (5.8%) patients. Multivariate regression demonstrated that hydronephrosis < 20 mm, total ultrasonographic guidance, solitary kidney, previous ipsilateral renal surgery, PCNL duration > 90 min and multiple bleeding sites were potential risk factors for initial embolization failure.

CONCLUSION

Percutaneous access was not the most important reason for post-PCNL severe haemorrhage. SRAE is effective for the treatment of severe haemorrhage following PCNL; however, several factors have an impact on the success of initial SRAE. Additionally, the SRAE procedure may affect renal function.

A mathematical method to estimate angle and distance for percutaneous renal puncture based on computed tomography data: Description and validation

Introduction

Gaining access to the kidney is crucial step in percutaneous nephrolithotomy (PCNL); it has a steep learning curve.

Objective

Describe the mathematical method to predict renal puncture angle and distance based on preoperative computed tomography (CT) measurements. Then evaluating how it correlates with measured values.

Patients and Methods

The study was prospectively designed. After ethical committee approval, the study uses data from preoperative CT to construct a triangle so we can estimate puncture depth and angle. A triangle of three points, the first is point of entry to the pelvicalyceal system (PCS), the second is point on the skin perpendicular to it, and the third where the needle punctures the skin. The needle travel is estimated using the Pythagorean theorem and puncture angle using the inverse sine function. We evaluated 40 punctures in 36 PCNL procedures. After PCS puncture using fluoroscopy-guided triangulation, we measured the needle travel distance and angle to the horizontal plane. Then compared the results with mathematically estimated values.

Results

We targeted posterior lower calyx in 21 (70%) case. The correlation between measured and estimated needle travel distance with Rho coefficient of 0.76 with P < 0.001. The mean difference between the estimated and the measured needle travel was - 0.37 ± 1.2 cm (-2.6-1.6). Measured and estimated angle correlate with Rho coefficient of 0.77 and P < 0.001. The mean difference between the estimated and the measured angle was 2° ± 8° (-21°-16°).

Conclusion

Mathematical estimation of needle depth and angle for gaining access to the kidney correlates well with measured values.

Comparing the outcomes of papillary and non-papillary access in percutaneous nephrolithotomy

BACKGROUND

Some publications have recently been released on the safety of non-papillary access (NPA) in percutaneous nephrolithotomy (PCNL) by a Greek group. The purpose of this study was to prospectively examine the outcome of NPA during two years in a referral center.

METHODS

This prospective cohort study was conducted on PCNL operations performed from January 2020 to April 2022 in Labbafinejad Hospital. In cases in which obtaining papillary access (PA) was not obtainable after several attempts and NPA was obtained, or in cases in whom after entry to the pyelocalyceal system, a NPA was observed, the cases were categorized in the NPA group (n = 67). The control group (PA) was composed of patients who had undergone PCNL with papillary access with similar stone bulk (n = 67). The primary endpoints of interest were hemoglobin drop and transfusion frequency. The secondary endpoint included: stone free rate (SFR), operation duration, and complications.

RESULTS

A total of 134 patients were enrolled during the study period which included 33 female patients (25%). The mean ± SD age of patients was 49.6 ± 13.2 years. The frequency of transfusion and residual stones was not different between NPA and PA groups: 6 (9%) versus 8 (11%), P = 0.29; and 16 (24%) versus 12 (18%), P = 0.26. Likewise, the operation time (87.6 ± 25.8 versus 90.2 ± 22.6 min, P = 0.45), and the frequency of intraoperative and postoperative complications were not different between the NPA and PA groups.

CONCLUSION

The results of this prospective study did not reveal a higher frequency of residual stones, transfusion, or complications in the NPA group. Nevertheless, our study is not powered enough to reveal complications of low frequency including delayed bleeding.

Risk Factors for Intra-operative Bleeding in Percutaneous Nephrolithotomy in an Academic Center: A Retrospective Study

Background

Percutaneous nephrolithotomy (PNL) is the treatment of choice for renal stones as a safe, effective, and minimally invasive method. However, bleeding remains a major concern in the procedure.

Objectives

This study aimed to investigate the risk factors of bleeding in PNL.

Methods

This retrospective descriptive cross-sectional study was conducted in the Urology department of Razi hospital. The data of patients with urinary calculi staghorn type who underwent PNL in a prone position under general anesthesia were recorded. A checklist including patients' demographics, surgical characteristics, and outcomes was filled out for each patient.

Results

The data from 151 complete files were gathered. The mean age of the cases was 47.89 ± 12.41 years. The mean hemoglobin (Hb) drop was 1.92 ± 1.56 mg/dL. At least 1 mg/dL Hb drop was observed in all cases. The highest Hb drop was 3 mg/dL.). There was no significant relationship between stone bulk, age, BMI, GFR, surgery duration, and the number of tracts, and Hb drop during PNL (P > 0.05). But there was a positive correlation between Urinary Tract Infection (UTI) history (P = 0.01) and transfusion (P = 0.0001) and Hb drop during PNL. Also, the history of open kidney surgery (P = 0.031), nephrostomy insertion (P = 0.003), and extracorporeal shock wave lithotripsy therapy (ESWL) (P = 0.041) were correlated with the increased risk of Hb drop.

Conclusions

Urinary tract infection, history of open surgery, nephrostomy implantation, and ESWL were significantly associated with more bleeding in PNL.

Renal pelvis mucosal artery hemorrhage after percutaneous nephrolithotomy: a rare case report and literature review

BACKGROUND

Following a percutaneous nephrolithotomy (PCNL) procedure, the most common complications are considered to be intraoperative and postoperative bleeding. Many patients with postoperative bleeding can be treated conservatively, causing the perirenal hematoma to resolve spontaneously. The major causes of severe postoperative bleeding are pseudoaneurysms, arteriovenous fistula, and segmental arterial injury. Typically, the first choice of treatment to manage severe bleeding complications is selective angioembolization (SAE) because of the very high success rate associated with this procedure.

CASE PRESENTATION

This clinical case involves a 56-year-old man who underwent dual-channel PCNL treatment after diagnosing a left kidney staghorn stone and urinary tract infection. The operation was successful, with no apparent signs of bleeding. Tests revealed continued decreasing hemoglobin levels following the procedure. After the conservative treatment failed, renal angiography was performed immediately, indicating renal pelvis mucosal artery hemorrhage. In the three hours post-surgery, the SAE still failed to prevent bleeding. Further discussions led to formulating a new surgical plan using a nephroscope to enter the initial channel where hemostasis began. The hemostasis origin was found precisely in the mucosal artery next to the channel during the operation and was successfully controlled.

CONCLUSIONS

This case reveals there is poor communication and inadequate discussions about the potential failures of an SAE procedure. Swift clinical decision-making is imperative when dealing with high-level renal trauma to prevent delays in surgery that can threaten the safety of patients.

Feasibility of contrast-enhanced ultrasound and flank position during percutaneous nephrolithotomy in patients with no apparent hydronephrosis: a randomized controlled trial

Purpose

To investigate the puncture accuracy and feasibility of contrast-enhanced ultrasound (CEUS) guided percutaneous nephrolithotomy (PCNL) in flank position for patients with no apparent hydronephrosis.

Methods

Between May 2018 and June 2020, 72 kidney stone patients with no or mild hydronephrosis were randomized into two groups: a CEUS-guided PCNL group and a conventional ultrasound (US)-guided group. Patients’ demographics and perioperative outcomes were compared, including the success rate of puncture via calyceal fornix, the success rate of a single-needle puncture, puncture time, operative time, postoperative hemoglobin loss, stone-free rate, incidence of complications and postoperative stay.

Results

The success rate of puncture via calyceal fornix for CEUS-guided group was significantly higher than that for conventional US-guided group (86.1 vs. 47.2%, p = 0.002). Patients performed with CEUS-guided PCNL required shorter renal puncture time than those guided with conventional US (36.5 s vs. 61.0 s, p < 0.001). The median postoperative hemoglobin loss in the CEUS-guided group was significantly lower than that in conventional US-guided group (2.5 vs. 14.5 g/L, p < 0.01). There was no statistically significant difference in the success rate of a single-needle puncture, operative time, stone-free rate, incidence of complications and postoperative stay between the two groups.

Conclusion

CEUS guidance facilitates identification of the renal calyx fornix, and benefits more precise renal puncture and less hemoglobin loss in PCNL. CEUS-guided PCNL in flank position is a feasible approach to the treatment of kidney stone patients with no apparent hydronephrosis.

Trial registration number: ChiCTR1800015417.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-03933-4.

Percutaneous puncture during PCNL: new perspective for the future with virtual imaging guidance

CONTEXT

Large and complex renal stones are usually treated with percutaneous nephrolithotomy (PCNL). One of the crucial steps in this procedure is the access to the collecting system with the percutaneous puncture and this maneuver leads to a risk of vascular and neighboring organs' injury. In the last years, the application of virtual image-guided surgery has gained wide diffusion even in this specific field.

OBJECTIVES

To provide a short overview of the most recent evidence on current applications of virtual imaging guidance for PCNL.

EVIDENCE ACQUISITION

A non-systematic review of the literature was performed. Medline, PubMed, the Cochrane Database and Embase were screened for studies regarding the use virtual imaging guidance for PCNL.

EVIDENCE SYNTHESIS

3D virtual navigation technology for PCNL was first used in urology with the purpose of surgical training and surgical planning; subsequently, the field of surgical navigation with different modalities (from cognitive to augmented reality or mixed reality) had been explored. Finally, anecdotal preliminary experiences explored the potential application of artificial intelligence guidance for percutaneous puncture.

CONCLUSION

Nowadays, many experiences proved the potential benefit of virtual guidance for surgical simulation and training. Focusing on surgery, this tool revealed to be useful both for surgical planning, allowed to achieve a better surgical performance, and for surgical navigation by using augmented reality and mixed reality systems aimed to assist the surgeon in real time during the intervention.

No staghorn calculi and none/mild hydronephrosis may be risk factors for severe bleeding complications after percutaneous nephrolithotomy

Background

To explore the risk factors for severe bleeding complications after percutaneous nephrolithotomy (PCNL) according to the modified Clavien scoring system.

Methods

We retrospectively analysed 2981 patients who received percutaneous nephrolithotomies from January 2014 to December 2020. Study inclusion criteria were PCNL and postoperative mild or severe renal haemorrhage in accordance with the modified Clavien scoring system. Mild bleeding complications included Clavien 2, while severe bleeding complications were greater than Clavien 3a. It has a good prognosis and is more likely to be underestimated and ignored in retrospective studies in bleeding complications classified by Clavien 1, so no analysis about these was conducted in this study. Clinical features, medical comorbidities and perioperative characteristics were analysed. Chi-square, independent t tests, Pearson’s correlation, Fisher exact tests, Mann–Whitney and multivariate logistic regression were used as appropriate.

Results

Of the 2981 patients 70 (2.3%), met study inclusion criteria, consisting of 51 men and 19 women, 48 patients had severe bleeding complications. The remaining 22 patients had mild bleeding. Patients with postoperative severe bleeding complications were more likely to have no or slight degree of hydronephrosis and have no staghorn calculi on univariate analysis (p < 0.05). Staghorn calculi (OR, 95% CI, p value 0.218, 0.068–0.700, 0.010) and hydronephrosis (OR, 95% CI, p value 0.271, 0.083–0.887, 0.031) were independent predictors for severe bleeding via multivariate logistic regression analysis. Other factors, such as history of PCNL, multiple kidney stones, site of puncture calyx and mean corrected intraoperative haemoglobin drop were not related to postoperative severe bleedings.

Conclusions

The absence of staghorn calculi and a no or mild hydronephrosis were related to an increased risk of post-percutaneous nephrolithotomy severe bleeding complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00866-9.

Percutaneous nephrolithotomy - the puncture

OBJECTIVE

To determine what importance is given to the puncture and assistive technologies in percutaneous nephrolithotomy (PNL) in the current urological literature.

METHODS

PubMed was searched for English publications and reviews for the keywords: 'percutaneous nephrolithotomy', 'percutaneous nephrostomy', 'puncture'. The search was limited to the last 5 years, January 2016 until February 2021. Based on 183 abstracts, 121 publications were selected, read, and reviewed. References, older or seminal papers were read and cited if they contributed to a better understanding. A total of 198 references form the basis of this narrative review.

RESULTS

The puncture is frequently referred to as the most crucial part of PNL. In contrast, the influence of the puncture on the failure rate of PNL and the specific puncture-related complications seems to be low in the single-digit percentage range. However, there are no universally accepted definitions and standards measuring the quality of puncture. Consequently, the impact of the puncture on general PNL complications, on stone scores predicting success rates and on learning curves evaluating surgeons' performance have not been systematically studied. Assistive technologies rely on fluoroscopy and ultrasonography, the latter of which is becoming the preferred imaging modality for monitoring the entire procedure. Needle bending, a problem relevant to all puncture techniques, is not addressed in the urological literature.

CONCLUSIONS

The importance attached to puncture in PNL in the current urological literature is subjectively high but objectively low. Some basics of puncture are not well understood in urology. Disciplines other than urology are more actively involved in the development of puncture techniques.

Technical aspects to maximize the hyperaccuracy three-dimensional (HA3D™) computed tomography reconstruction for kidney stones surgery: a pilot study

The aim of the current prospective pilot study was to describe a hyperaccuracy three-dimensional (HA3D^™) model reconstruction technique, specifically developed to maximize the visualization of the renal collecting system's anatomy, and its relationship with the stones, vessels and renal parenchyma, and to compare the HA3D^™ virtual models with the intraoperative findings. The image acquisition was performed using a CT scanner (Toshiba, Aquilion Prime) and included the unenhanced, arterial, venous and excretory phases. The DICOM format CT images were processed by MEDICS Srl ( www.medics3d.com , Turin, Italy). In total, study included three patients with renal stone scheduled for non-papillary prone percutaneous nephrolithotomy (PCNL). The median age and BMI were 51 (range 49-54) and 25.5 (range 25.0-32.7), respectively. The median stone size was 1170 mm² (range 830-1520) and median stone density was 1130 HU (range 600-1340). In all cases, the quality of the CT images acquired with our protocol was adequate to perform the HA3D^™ reconstruction. Median operative and puncture time were 39.4 (range 35.2-44.0) and 1.9 (range 1.8-2.1) mins, respectively. The success rate for the first attempt of the percutaneous puncture was 100%, and only one PCNL tract was sufficient to complete the surgery. All three patients were stone-free on the third postoperative day. A dedicated imaging acquisition protocol and a tailored 3D model reconstruction process specifically developed for kidney stones treatment allow obtaining HA3D^™ highly relevant models to greatly match intraoperative findings during PCNL with the potential of minimizing bleeding and organ injury complications.

Superselective Renal Artery Embolization Management of Post-percutaneous Nephrolithotomy Hemorrhage and Its Methods

Objective: The purpose of this study was to evaluate the therapeutic efficacy and safety of superselective renal arterial embolization (SRAE) in the treatment of patients with renal hemorrhage after percutaneous nephroscopy (PCNL). In addition, embolization techniques and embolization materials during operation were also worthy of further discussion.

Methods: From February 2015 to December 2019, clinical data of 49 consecutive patients with renal hemorrhage after PCNL were retrospectively analyzed. Demographic and clinical data of patients were recorded, changes in serum creatinine values were analyzed, and the safety and efficacy of TAE were evaluated. Clinical experience was also recorded.

Results: A total of 49 patients underwent angiography, of which 46 patients received SRAE due to positive hemorrhagic foci detected by angiography, and the technical success rate of 46 patients was 100%. Among the three patients who did not receive embolization, one patient underwent nephrectomy, and two patients improved with conservative treatment, with a clinical success rate of 98%. There was no statistically significant difference between serum creatinine before PCNL and 7 days after SRAE (101.6 ± 36.5 to 100.5 ± 27.1 μmol/L; P = 0.634), and no significant change was observed in serum creatinine at the last follow-up (99.4 ± 34 μmol/L, P = 0.076). No major complications occurred after embolization.

Conclusions: SRAE is safe and effective in patients with renal hemorrhage after PCNL. The experience of interventional therapy and the choice of embolization materials in this study may provide certain benefits for the treatment of patients with renal hemorrhage after PCNL.