[Roadmap of ultrasound-guided percutaneous access to the renal collecting system]

INTRODUCTION

The key point of successful PCNL is getting access to the renal collecting system. Ureteral catheterization and injection of contrast material provide an important advantage of visualizing and dilating the collecting system. However, catheterization increases the operation time, exposure to anesthesia, and requires additional reusable and disposable medical supplies. The purpose of the study was to develop a surgical algorithm for accessing the renal collecting system for mini-PCNL without catheterization.

MATERIALS AND METHODS

We analyzed the treatment results of 82 patients with a single kidney stone, who underwent mini-PCNL without prior catheterization of the ureter. The percutaneous access was obtained according to the roadmap we had developed. The puncture was performed under X-ray control and US guidance. For a calyx stone, the puncture was performed "to the stone". For a pelvis stone, the targeted calyx was accessed using the following algorithm where each next step was performed if the puncture had been impossible at the previous one: 1. 30 min before the operation: infusion load of normal saline, 1000 ml. 2. Intraoperatively: intravenous furosemide, 60 mg. 3. Puncture "to the pelvic stone", injecting contrast material into the collecting system and correcting the access puncture through the required calyx.

RESULTS

In all 82 cases, puncture access was performed without ureteral catheterization. In 20 patients with calyceal stones, puncture onto a stone was successfully performed in 100% of the cases. Of 62 patients with pelvic stones, preliminary infusion was enough to allow a successful puncture in 49 (79%), access after intravenous administration of furosemide was obtained in 13 (21%), and a primary puncture onto a pelvic stone had to be done in 6 (10%) patients.

CONCLUSIONS

Our proposed algorithm for accessing the PCS of the kidney was successfully used in 100% of the cases. It makes possible to avoid routine ureteral catheterization and thus reduce the overall operation time and the risk of complications, as well as save medical supplies. Clearly, such results require that the surgeon should have significant experience with puncture interventions under ultrasound control.

[Calico-venous fistulae: an intrarenal complication of percutaneous nephrolithotomy]

Bleeding is a serious complication of percutaneous nephrolithotomy (PCNL). A rare cause of gross hematuria is a calico-venous fistula. A clinical case of successful intraoperative diagnosis and treatment of calico-venous fistula during PCNL is presented in the article. Description of a clinical case. A patient J., 53 years old, underwent examination and treatment at the Institute of Urology and Reproductive Health, FGAOU VO I.M. Sechenov First Moscow State Medical University with a diagnosis of staghorn stone of the right kidney, a stone of the left kidney, chronic right-side pyelonephritis. On June 15, 2021, mini-PCNL was performed for the staghorn stone of the right kidney. The procedure seemed to be unremarkable, but during intraoperative antegrade pyelography, the inflow of contrast agent from the lower calyxes into the posterior segmental vein of the right kidney was detected, which was managed by creating sufficient traction of the nephrostomy drainage. Communication of the collecting and venous systems of the kidney is associated with a risk of both severe gross hematuria and urine flow into the venous bed. The urine flow into the bloodstream may result in hemodynamic disturbances, up to collapse followed by cardiac arrest. In order to prevent complications of PCNL it is necessary to analyze the kidney anatomy based on three-dimensional modeling of contrast- enhanced computed tomography. A calicovenous fistula can be a source of risk of bleeding and severe complications. To minimize intraoperative damage to parenchymal structures, an analysis of three-dimensional modeling of a kidney in patients with staghorn calculus based on computed tomography is required, which allows rational planning of surgical tactics.

Automated Machine Learning Segmentation and Measurement of Urinary Stones on CT Scan

OBJECTIVES

To evaluate the performance of an engineered machine learning algorithm to identify kidney stones and measure stone characteristics without the need for human input.

METHODS

We performed a cross-sectional study of 94 children and adults who had kidney stones identified on non-contrast CT. A previously developed deep learning algorithm was trained to segment renal anatomy and kidney stones and to measure stone features. The performance and speed of the algorithm to measure renal anatomy and kidney stone features were compared to the current gold standard of human measurement performed by 3 independent reviewers.

RESULTS

The algorithm was 100% sensitive and 100% specific in detecting individual kidney stones. The mean stone volume segmented by the algorithm was smaller than that of human reviewers and had moderate overlap (Dice score: 0.66). There was substantial variation between human reviewers in total segmented stone volume (Jaccard score: 0.17) and volume of the single largest stone (Jaccard score: 0.33). Stone segmentations performed by the machine learning algorithm more precisely approximated stone borders than those performed by human reviewers on qualitative assessment.

CONCLUSION

An engineered machine learning algorithm can identify and characterize stones more accurately and reliably than humans, which has the potential to improve the precision and efficiency of assessing kidney stone burden.

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

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

High attenuation value in non-contrast computer tomography can predict pyonephrosis in patients with upper urinary tract stones

To evaluate whether the higher attenuation value [Hounsfield unit (HU)] in non-contrast CT can predict pyonephrosis in patients with upper urinary tract stones (UTS). Between October 2019 and October 2021, patients with hydronephrosis or pyonephrosis secondary to upper UTS were retrospectively searched in our study. All patients with UTS were treated with percutaneous nephrostomy, percutaneous nephrolithotomy, retrograde ureteral stent or transurethral ureteroscope lithotripsy. We excluded patients treated with extracorporeal shock-wave lithotripsy. Patients whose CT was not performed in our hospital or treated in another hospital were also excluded. Clinical data regarding basic information, clinical feature, Calculi-related indicators, HU values of the renal pelvis, the thick wall of the renal pelvis on CT were collected. Univariate and multivariate logistic analyses were performed. Receiver operative characteristic curves were drawn to predict pyonephrosis. A total of 240 patients with UTS were retrospected in this research, 191 patients had hydronephrosis (Group 1), and 49 patients had hydronephrosis with pyonephrosis (Group 2). The HU value of the renal collecting system in Group 2 (mean, 15.46; range, +1/+30) was significantly higher than that in Group 1 (mean, 5.5; 5 range -6/+24) (P = .02); the receiver operative characteristic curve analysis revealed that the best cut-off value of 9.5 could predict the presence of pyonephrosis, with 71.4% sensitivity and 70.2% specificity (area under the curve = 0.613; 95% CI: 0.514-0.713). In this study, we found the HU attenuation value of the renal collecting system can be used to distinguish pyonephrosis from hydronephrosis in patients with UTS.

Reducing the rate of negative ureteroscopy: predictive factors and the role of preoperative imaging

INTRODUCTION

The aim of this study was to investigate factors that may predict a negative ureteroscopy (URS) performed for ureteric calculi in prestented patients and to assess preoperative imaging in reducing the rate of negative URS.

METHODS

Data were collected on emergency stent placement for a ureteric calculus from April 2011 to February 2016 (Group A) and October 2016 to October 2019 (Group B). Data included patient demographics, indication for a stent, stone characteristics, baseline bloods, urine culture, readmission, negative URS rate and the use of pre-URS imaging. Multivariate logistic regression was used for statistical analysis.

RESULTS

Of 257 patients who underwent emergency stent insertion, 251 underwent deferred URS for a ureteric calculus and 6 avoided URS due to pre-URS imaging. Indications for stent were pain (42%), sepsis (39%) and acute kidney injury (19%). Mean stone size was 7.8mm, mean stone density was 699 Hounsfield units (HU) and the stone locations were upper (62%), mid (13%) and lower ureter (25%). The overall negative URS rate was 12%. The negative URS rate was lower in patients with pre-URS imaging compared with those with none, 6% and 14%, respectively (OR=2.33, 95% CI: 0.69-7.56, p=0.2214). Logistic regression analysis indicated stone size as the only significant predictor of a negative URS, where the greater the size of the stone the less likely URS would be negative (β=0.75, 95% CI: 0.60-0.94 p=0.011).

CONCLUSIONS

Utilising pre-URS imaging can lead to a reduction in negative URS rate. Stone size <5mm appears to be the subgroup most likely to benefit from imaging.

[Comparative study of the influense of stone size and volume on the duration of thulium laser percutaneous nephrolithotripsy]

OBJECTIVE

The aim of the investigation was to determine the influence of such parametric characteristics of the stone such as size and volume on the duration of tulium laser disintegration of the urinary stone and to determine which of these parameters is more effective to use like prognostic criterion for the duration of the planned surgical intervention in the percutaneous nephrolithotripsy.

MATERIALS AND METHODS

Overall 52 patients (27 females and 25 males) with an average age of 56,9 (25-79) years participated in the present study. All patients underwent percutaneous nephrolithotripsy with disintegration of the kidney stone by thulium energy. Inclusion criteria were: stone size more or equal 2 cm, stone density >1100 HU. Exclusion criteria were: patients with a single kidney, urinary tract divertions, coagulopathy. The average operation time was 30 (15-100) minutes, with an average puncture time of 3.15 (1-10) minutes and lithotripsy time of 28 (14-98) minutes. To determine the volume we used the method of automatic lithometry according to CT data using the software: Vitrea ver. 4.1.52. The size of the stone was determined by the longest length in one of the plane. During the study it was found that the average size of the stone was 28.25 (20-58) mm and the average volume was 2579.4 (250-9990) mm3. To confirm our assumption, we decided to determine the dependence of the time of disintegration of the stone on the size and volume of the stone. For this purpose, we graphically presented the correlation of these parameters.

RESULTS

We have drawn 2 graphs reflecting the dependence of lithotripsy time parameters on the size and volume characteristics of the stone. As a result of comparing these parameters we found that size is a prognostically less reliable predictor of lithotripsy time, and is not characterized by a linear distribution, in contrast to the stone volume.

CONCLUSIONS

Thereby, the main stereoscopic characteristic of a stone is a volume, which should be the primary guide in selecting the preferred method of treatment as well as in predicting the operative time and associated risks.

Application of CTU-Assisted Doppler Ultrasound Puncture in Nontube Percutaneous Nephrolithotomy, Its Effect on Patients' Complications, and Its Clinical Value

Objective

To research the application of CTU-assisted Doppler ultrasound puncture in uncatheterized PCNL, its influence on patients' complications, and its clinical value in a case-control study.

Methods

One hundred and forty-four patients who went through percutaneous nephrolithotomy (PCNL) from March 2019 to June 2021 in our hospital were arbitrarily assigned into the CTU group (n = 72) and CT plain scan group (n = 72). CTA+CTU was adopted to determine the puncture passage in the CTU group, and CT scan was employed in the CT group. The intraoperative blood loss, postoperative blood loss, operation time, hospital stay, primary stone removal rate, and the incidence of intraoperative and postoperative complications were compared. The visual analogue score (VAS) was employed to assess the degree of postoperative wound pain.

Results

The first-stage stone removal rate in the CTU group was 95.83% (69/72), which was remarkably higher compared to the CT plain scan group, which was 81.94% (59/72), and the difference was statistically significant (P < 0.05). The overall rates of intraoperative complications were 6.94% (5/72) in the CTU group and 18.06% (13/72) in the CT plain scan group, respectively, which exhibited great differences (P < 0.05). In addition, the overall rates of intraoperative complications were 2.78% (2/72) in the CTU and 13.89% (10/72) in the CT plain scan group, respectively, and the difference was statistically significant (P < 0.05). The operation time and postoperative hospital stays in the CTU group were remarkably shorter compared to the CT group, and the difference was statistically significant (P < 0.05). The intraoperative and postoperative blood loss of CTU group displayed obvious less than that of the CT group, and the difference was statistically significant (P < 0.05). The VAS were compared 24 hours after surgery. After operation, the VAS of 24 hours after operation in the CTU group (0.92 ± 0.12) were remarkably lower compared to the CT group (1.22 ± 0.15), and the difference was statistically significant (P < 0.05). Discussion. PCNL is constantly being optimized by CTU-assisted Doppler ultrasound puncture to improve stone clearance rates, reduce postoperative bleeding, be less painful, provide rapid recovery, and provide safe and feasible results. It is therefore worthwhile to standardize and then widely promote it in clinical practice.

Percutaneous nephrolithotomy with ultrasonography-guided renal access in the modified lateral position with extended legs

PURPOSE

This study was to evaluate the safety and efficacy of ultrasound-guided percutaneous nephrolithotomy (US-guided PCNL) in a modified lateral position with extended legs for kidney stones.

METHODS

This prospective study included 46 patients underwent PCNL with US-guided renal access in the modified lateral position with extended legs from 2020 to 2021. The outcomes included the rate of successful access, complete stone clearance, operative characteristics, postoperative complications, and the need for an additional procedure.

RESULTS

Median age was 54.5 years and males were 56.5%. Median stone burden was 2,660 mm3 and 93.5% of all patients were graded as 1 or 2 regarding the Guy's stone score. Twenty-four patients required one puncture and 14 patients required 2 punctures. Six patients had a concomitant ureteroscopic lithotripsy. Median access duration, fluoroscopy duration and hospital length of stay were 2.0 minutes, 14.5 seconds and 3 days respectively. Successful renal access rate was 100% and complete stone clearance rate was 93.5%. Complications occurred in 5 patients without mortality. Three patients required an additional procedure.

CONCLUSION

US-guided PCNL in the modified lateral position with extended legs is safe and effective for kidney stones. The exposure to radiation is reduced significantly. We advocate using this approach and try to perform PCNL under X-ray free US guidance.

The effects of stone density on surgical outcomes of retrograde intrarenal stone surgery

OBJECTIVE

Several pre-operative parameters have been studied to estimate stone-free rate (SFR) following retrograde intrarenal surgery (RIRS) procedures. The objective of this study was to evaluate the effects of stone density on surgical outcomes of RIRS.

METHODS

This retrospective study included 30 stone-free patients (Group SF) and 30 patients with residual fragments (Group RF). Patients' age and gender, laterality, non-contrast CT findings, including size and density of the kidney stones, infundibular pelvic angle (IPA), operational time, and post-operative pain were recorded and compared between the two groups. The stone density was measured by free hand region of interest (ROI) determination coincident with the stone borders and expressed as Hounsfield units (HUs).

RESULTS

The rate of single stones was significantly higher in Group SF compared to Group RF (p < 0.001). The mean stone size was found as 11.93 ± 7.81 mm in Group SF and 16.27 ± 7.29 mm in Group RF with the difference being statistically significant (p < 0.001). The mean IPA was 53.87 degrees in Group SF and 50.33 degrees in Group RF. The mean density was measured as 748.17 ± 318.14 HU in Group SF and 945.90 ± 345.30 HU in Group RF. The mean stone density was statistically significantly higher in patients with residual fragments compared to the stone-free patients (p < 0.001).

CONCLUSION

This study revealed that stone density as measured as HU affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments.

ADVANCES IN KNOWLEDGE

Studies about the effects of HUs on stone-free rate are limited in the literature. Stone density affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments.

Detection of the mineral constituents in human renal calculi by vibrational spectroscopic analysis combined with allied techniques Powder XRD, TGA, SEM, IR imaging and TXRF

Detection of the mineral constituents in a batch of 310 samples of human urinary calculi (kidney stones-235 and bladder stones-75) combined with a semi-quantitative analysis has been presented on the basis of Fourier Transform based IR and Raman spectral measurements. Some of the observed characteristic IR and Raman bands have been proposed as 'Marker Bands' for the most reliable identification of the constituents. A detailed vibrational spectral analysis combined with a DFT level calculation for the functional groups in Calcium Oxalate Monohydrate (COM), Magnesium Ammonium Phosphate Hexahydrate (MAPH), Calcium Hydrogen Phosphate Dihydrate (CHPD), Penta-Calcium Hydroxy-Triphosphate (PCHT) and Uric Acid (UA) has been proposed. It has been shown that the identified mineral constituents as major or minor components can be deduced from the application of Lambert-Beer law of radiation absorption and results are in agreement with quantitative Spectral Data base. This simple method has the potential to be integrated into the management of Urolithiasis, a process of forming renal calculi in the kidney, bladder and/or urethra. Employment of powder XRD, TGA, SEM, TXRF and IR Imaging techniques has provided additional support for the proposed foolproof identification of the mineral constituents. Among the mineral constituents, Calcium Oxalate Monohydrate, Calcium Oxalate Dihydrate or their mixture account for 85% of the total number of samples; the remaining 15% and 5% samples contain Phosphate and Uric acid stones respectively.

Finger touching combined X-ray-guided percutaneous nephrolithotomy in 640 cases: an 8-years' experience

OBJECTIVE

We aimed to evaluate the safety and efficacy of finger touching combined X-ray-guided percutaneous nephrolithotomy, and the feasibility of avoiding damage in medical staff caused by X-ray.

PATIENTS AND METHODS

From January 2013 to December 2020, 640 cases of percutaneous nephrolithotomy were performed through the 18-24-F channel. Among those cases, 22 (3.4%) cases were double-sided kidney stones surgeries, 294 (45.8%) cases were on the right side and 324 (50.5%) cases were on the left side. The targeted renal calyceal puncture was carried out under the combined guidance of the doctor's finger and X-ray. We assessed the X-ray exposure time of patients and doctors, average number of punctures, postoperative hospitalization, calculus removal rates, and complications.

RESULTS

The average number of punctures was 2.8 ± 1.4. Average X-ray exposure time during procedure: 2.8 s (range: 2-8 s). Average surgical time: 106.5 ± 49.4 min. Postoperative hospitalization: 6.8 ± 4.2 d. Average reduced hemoglobin level: 5.9 g/day. Stone-free rate 4 weeks after surgeries: 95.6%. Patients with upper ureteral calculi: 395 cases (61.72%). The calculus residual rate of patients with staghorn renal calculi or multiple renal calculi complementary treatments was 82.9%, including 0 patients who received shock wave lithotripsy, 2 cases of repeated percutaneous nephrolithotomy (PCNL), and 18 cases of ureteroscopy. Postoperative placement of renal drainage tube occurred in 52 cases. As for complications, no perirenal infection occurred, two severe bleeding complication cases occurred, and one case of colon perforation occurred.

CONCLUSIONS

Finger touching combined X-ray-guided percutaneous nephrolithotomy in patients with renal calculus is safe and can accurately guide the puncture without radiation hazards. The placement of a renal drainage tube was beneficial to reduce renal effusion, hematocele, and infections.

A deep learning system for automated kidney stone detection and volumetric segmentation on noncontrast CT scans

PURPOSE

Early detection and size quantification of renal calculi are important for optimizing treatment and preventing severe kidney stone disease. Prior work has shown that volumetric measurements of kidney stones are more informative and reproducible than linear measurements. Deep learning-based systems that use abdominal noncontrast computed tomography (CT) scans may assist in detection and reduce workload by removing the need for manual stone volume measurement. Prior to this work, no such system had been developed for use on noisy low-dose CT or tested on a large-scale external dataset.

METHODS

We used a dataset of 91 CT colonography (CTC) scans with manually marked kidney stones combined with 89 CTC scans without kidney stones. To compare with a prior work half the data was used for training and half for testing. A set of CTC scans from 6185 patients from a separate institution with patient-level labels were used as an external validation set. A 3D U-Net model was employed to segment the kidneys, followed by gradient-based anisotropic denoising, thresholding, and region growing. A 13 layer convolutional neural network classifier was then applied to distinguish kidney stones from false positive regions.

RESULTS

The system achieved a sensitivity of 0.86 at 0.5 false positives per scan on a challenging test set of low-dose CT with many small stones, an improvement over an earlier work that obtained a sensitivity of 0.52. The stone volume measurements correlated well with manual measurements (r 2 = 0.95 $r^2 = 0.95$ ). For patient-level classification, the system achieved an area under the receiver-operating characteristic of 0.95 on an external validation set (sensitivity = 0.88, specificity = 0.91 at the Youden point). A common cause of false positives were small atherosclerotic plaques in the renal sinus that simulated kidney stones.

CONCLUSIONS

Our deep-learning-based system showed improvements over a previously developed system that did not use deep learning, with even higher performance on an external validation set.

PCNL Combined with 3D Printing Technology for the Treatment of Complex Staghorn Kidney Stones

Objective

To explore the clinical application value of percutaneous nephrolithotripsy (PCNL) combined with 3D printing technology in the treatment of complex staghorn kidney stones.

Methods

From January 2018 to February 2020, a total of 72 patients with complex staghorn kidney stones admitted to our center were divided into experimental group (3D printing group) and control group (computed tomography, CT, imaging group)) according to the random block method, and a prospective cohort study was conducted. Preoperative computed tomography urography (CTU) examination was performed on all patients in the two groups, and the original CT scan Digital Imaging and Communications in Medicine (DICOM) data of patients in the experimental group were separately extracted for three-dimensional reconstruction and 3D model printing and designed a doctor-patient communication evaluation score table. The two groups were compared in score table, puncture location time, total operation time, consistency between estimated calyx and target calyx, incidence of surgical complications, stone free rate, postoperative recovery, and other aspects.

Results

Both groups completed preoperative CTU examination and showed good kidney and stone morphology. In the experimental group, all 3D printed models were completed and the internal anatomical structure could be clearly displayed. Simulation puncture and relevant measurement parameters could be obtained. The experimental group was significantly better than the control group in doctor-patient communication evaluation score, puncture location time, target calyx consistency, and stone free rate (p < 0.05), and there was no statistical difference in total operation time, postoperative complications, and postoperative recovery.

Conclusions

Individualized 3D printing technology can fully evaluate and design percutaneous renal access and stone clearing strategies before surgery. Compared with traditional preoperative imaging evaluation, 3D printing makes PCNL more accurate and efficient in the treatment of complex staghorn shaped kidney stones, with a high stone free rate at the first stage and better doctor-patient communication satisfaction.

[The tale of two stones in an obstructed partial duplex kidney: case presentation]

Duplex renal systems is a common anomalies. Incidence rate of 0.8% in healthy adult population and 2-4% in patients investigated for urinary tract symptoms. Urolithiasis management for patients with anomalies is complex and require proper imaging and planning. We have a patient with a partial duplex collecting system presented with a right renal calculus in a non-functioning lower moiety and multiple distal ureteric calculi. Preoperative planning done and surgery performed with good outcome without any early and late complications.

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.

Superselective renal arterial embolization in treatment for severe renal hemorrhage after flexible ureterorenoscopy and laser lithotripsy (FURSL)

OBJECTIVE

Life-threatening renal hemorrhage after flexible ureterorenoscopy and laser lithotripsy (FURSL) is a rare complication. We aim to review our unit's experience with super-selective renal artery embolization as therapeutic options for such patients.

METHODS

From January 2015 to November 2021, total 1125 patients underwent the FURSL procedures in our unit. Patients with life-threatening renal hemorrhage were reviewed and the information of peri-operative, operative and post-operative were recorded.

RESULTS

Of the 1125 patients who underwent FURSL procedure, two patients with life-threatening renal hemorrhage were diagnosis; the age is 67 and 42 years old, respectively. Preoperative imaging examination showed that two patients had upper ureteral stone and renal stone ranging in size from 1.2 to 3.0 cm. Female patient placed the D-J stent for two weeks before FURSL. After the operation, both patients had the massive gross hematuria, significant drop of hemoglobin (Hgb), blood pressure lowering and needed to transfusion. CT scan showed that the male patient had an intrarenal hematoma. All these two were treated by super-selective renal artery embolization and had a successful outcome.

CONCLUSION

Life-threatening renal hemorrhage after FURSL is a rare and severe complication. Super-selective renal artery embolization is a safe and effective method for the treatment of patients with severe renal hemorrhage, preserving healthy renal parenchyma and renal function.

Identification of the Risk Factors for the Failure of Ureteral Access Sheath Placement

PURPOSE

Insertion of a ureteral access sheath (UAS) may fail in some patients in retrograde intrarenal surgery (RIRS), and this study aimed to seek preoperative risk factors for the failure of 12/14F UAS placement.

METHODS

We retrospectively analyzed 260 consecutive patients who underwent RIRS between May 2020 and March 2022 at our institution. Data on patient and stone characteristics and several computed tomography (CT)-based measurements were collected and compared between the success and failure UAS placement groups.

RESULTS

Twenty-nine (11.2%) patients failed to insert the UAS. Age, gender, height, weight, stone side, stone location, length of history, and computed tomography (CT)-based parameters were not significant differences between the two groups. Univariate logistic regression analyses showed sex (female/male) (odds ratio: 0.287 and 95% CI [0.107, 0.722], p=0.013), length of history 15-31 days (odds ratio: 0.315 and 95% CI [0.102, 0.974], p=0.045), length of history >31 days (odds ratio: 0.202 and 95% CI [0.051, 0.805], p=0.023), and diameter of the ipsilateral common iliac artery (odds ratio: 1.285 and 95% CI [1.018, 1.623], p=0.035) were associated with UAS placement.

CONCLUSION

Our study indicated that males, the short length of history, and the short diameter of the ipsilateral common iliac artery were the risk factors for the failure of UAS placement.

The clinical outcomes of flexible ureteroscopy and laser lithotripsy (FURSL) for treatment of the upper urinary tract calculi

PURPOSE

To evaluate efficacy and safety of flexible ureteroscopy and laser lithotripsy (FURSL) for treatment of the upper urinary tract calculi.

METHODS

We retrospectively analyzed 784 patients who underwent FURSL between January 2015 and October 2020 in our unit. All patients were preoperatively evaluated with urine analysis, serum biochemistry, urinary ultrasonography, non-contrast computed tomography and intravenous urography. The procedure was considered as successful in patients with complete stone disappearance or fragments < 4 mm on B ultrasound or computed tomography. The operative parameters, postoperative outcomes and complications were recorded and analyzed respectively.

RESULTS

The average operative time and postoperative hospital stay were 46.9±15.8 min and 1.2±1.1 days, respectively, among 784 patients. In addition, 746 patients were followed up and 38 patients were lost. In these patients, 700 (93.8%) cases met the stone removal criteria and 46 cases (6.2%) did not meet the stone removal criteria who need further treatment. The stone free rate (SFR) is 92.5%after 1-3 months and SFR of middle and upper calyceal calculi was higher than that of lower calyceal calculi significantly. The most common complications were fever (58/784, 7.4%), gross hematuria (540/784, 68.9%) and lpsilateral low back pain (47/784, 6.0%). The incidence rate of serious complication was 1.28%(10/784), including 5 cases of septic shock and 5 cases of subcapsular hematoma, which were cured after active treatment.

CONCLUSION

FURSL is a reliable treatment for small and medium calculi patients of upper urinary tract. The curative effect of stone removal is clear. The complications are few and the safety is high. However, there are certain limitations to the efficacy in treating larger stone and lower calyceal calculi.

CHARACTERISTICS OF CERTAIN INDICES OF MINERAL METABOLISM IN CHILDREN WITH KIDNEY CALCULI

OBJECTIVE

The aim: To study the violations of bone density indices in patients with kidney calculi.

PATIENTS AND METHODS

Materials and methods: 175 children with different types of kidney calculi were examined and treated in Ivano-Frankivsk Regional Children's Consultative Polyclinics and Hospital, from 2016 to 2019 inclusively. Comprehensive metabolic panel involved by means of generally accepted biochemical methods. Sonography of the urinary tract was carried out. Voiding cystourethrography and excretory urography were performed. Bone mineral density was evaluated by means of ultrasonic densitometry. Statistical processing of the obtained data was carried out according to standard methods of variation statistics.

RESULTS

Results: In patients with kidney calculi, oxaluria and oxalate-calcium nephropathy (60.0% and 30.0%, p <0.05) occurred most frequently. Signs of syndrome of undifferentiated connective tissue dysplasia - postural malformation (50.0%), thoracic kyphosis (25.0%), and stigmas of dysembryogenesis (25.0%) were noticed. In the majority of children with oxalate-calcium nephropathy, levels of the bone alkaline and acid phosphatase isoenzymes in a blood serum were significantly high, indicating severity of the resorption and disorders in development of the bone tissue. In these children, decreased fraction of ionized calcium, hypomagniemia and hypophosphatemia were observed.

CONCLUSION

Conclusions: Children with oxalate-calcium nephropathy are in group of risk for osteopenic syndrome.

Comparison of the outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for the treatment of kidney stones: a matched-pair analysis

OBJECTIVE

Mini-percutaneous nephrolithotomy is a recent advancement in the field of kidney stone treatment; however, its role has not been completely established. We aimed to compare the outcomes of initial Mini-percutaneous nephrolithotomy and flexible ureteroscopy.

METHODS

A retrospective review of consecutive mini-percutaneous procedures was performed. Inclusion criteria were as follows: all percutaneous nephrolithotomy procedures performed with an access sheath up to 24Fr, kidney stone burdens up to 1550 mm3; and the presence of postoperative computed tomography (for control). The data collected for Mini-percutaneous nephrolithotomy procedures were paired 1:2 with patients treated with flexible ureteroscopy for stones between 100 and 1550 mm3, and with postoperative computed tomography for control. A 14Fr Mini-percutaneous nephrolithotomy set was used. The stone-free rate was defined as the absence of fragments on the control computed tomography, whereas success was limited to 2-mm residual fragments. Statistical analysis was performed using SPSS version 19.

RESULTS

A total of 63 patients met the inclusion criteria (42 with flexible ureteroscopy and 21 with mini-percutaneous nephrolithotomy). Demographic data were comparable. The stone-free rate and success were similar between the groups (76.2 vs. 66.7%, p=0.42 and 90.5 vs. 85.7%, p=0.57). The complication rate was also similar (26.1 vs. 9.6%, p=0.188), but Mini-percutaneous nephrolithotomy had longer hospitalization and fluoroscopy time (p=0.001 in both).

CONCLUSIONS

Our initial study of Mini-percutaneous nephrolithotomy showed that it is a promising procedure, with outcomes similar to flexible ureteroscopy, but with higher inpatient numbers and fluoroscopy times. A larger study population size and better equipment may improve the outcomes of mini-percutaneous nephrolithotomy.

[A Case of Calyceal Diverticula with Stones Treated by Ureteroscopic Management]

Most patients with calyceal diverticula stones are asymptomatic, but some patients experience fever and low back pain. Here we report a case of calyceal diverticula stones treated by ureteroscopic management. A 41-year-old woman with backache visited a local doctor. She was diagnosed with a urinary tract infection, and prescribed an antibiotic. Her symptoms began to improve, but the ultrasonography showed she had a left renal cystic lesion, so she visited our hospital. Abdominal contrast-enhanced computed tomography (CT) showing in-flow of a contrast agent into the left renal calyceal diverticula located stones in the upper pole. We performed ureteroscopic management of the calyceal diverticula stones in two stages. First, we expanded the neck of the calyceal diverticula by indwelling the ureteral stent at the calyceal diverticula. Then, using a ureteral dilator, we expanded the neck of the calyceal diverticula further and removed the stones in the calyceal diverticula. Treatment with ureteroscopic management was possible due to the location of the calyceal diverticula stones and the success rate was increased by performing the treatment in two stages.