Develop a radiomics-based machine learning model to predict the stone-free rate post-percutaneous nephrolithotomy.

Radiomics and machine learning have been extensively utilized in the realm of urinary stones, particularly in forecasting stone treatment outcomes. The objective of this study was to integrate clinical variables and radiomic features to develop a machine learning model for predicting the stone-free rate (SFR) following percutaneous nephrolithotomy (PCNL). A total of 212 eligible patients who underwent PCNL surgery at the Second Affiliated Hospital of Nanchang University were included in a retrospective analysis. Preoperative clinical variables and non-contrast-enhanced CT images of all patients were collected, and radiomic features were extracted after delineating the stone ROI. Univariate analysis was conducted to identify clinical variables strongly correlated with the stone-free rate after PCNL, and the least absolute shrinkage and selection operator algorithm (lasso regression) was utilized to screen radiomic features. Four supervised machine learning algorithms, including Logistic Regression, Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Gradient Boosting Decision Tree (GBDT), were employed. The clinical variables with strong correlation and screened radiomic features were integrated into the four machine learning algorithms to construct a prediction model, and the receiver operating curve was plotted. The area under the receiver operating curve (AUC), the accuracy rate, the specificity, etc., were used to evaluate the predictive performance of the four models. After analyzing postoperative statistics, the stone-free rate following the procedure was found to be 70.3% (n = 149). Among the various clinical variables examined, factors, such as stone number, stone diameter, stone CT value, stone location, and history of stone surgery, were identified as statistically significant in relation to the stone-free rate after PCNL. A total of 121 radiomic features were extracted, and through lasso regression, 7 features most closely associated with the stone-free rate post-PCNL were identified. The predictive accuracy of different models (Logistic Regression, RF, XGBoost, and GBDT) for determining the stone-free rate after PCNL was evaluated, yielding accuracies of 78.1%, 76.6%, 75.0%, and 73.4%, respectively. The corresponding area under the curve AUC (95%CI) were 0.85 (0.83-0.89), 0.81 (0.76-0.85), 0.82 (0.78-0.85), and 0.77 (0.73-0.81), positioning these models among the top performers in logistic regression prediction. In terms of predictive importance scores, the key factors identified by the logistic regression model were number of stone, zone percentage, stone diameter, and surface area. Similarly, the RF model highlighted number of stone, stone CT value, stone diameter, and surface area as the top predictors. Among the four machine learning models, the logistic regression model demonstrated the highest accuracy and discrimination ability in predicting the stone-free rate following PCNL. In comparison to XGBoost and GBDT, RF also exhibited superior accuracy and a certain level of discrimination ability. However, based on the performance of all four models, logistic regression is more likely to aid in clinical decision-making by assisting clinicians in diagnosing PCNL in patients. This enables us to effectively predict the presence of residual stones post-surgery and ultimately select patients who are suitable candidates for PCNL.

Comparison of safety and efficacy of tubeless vs. conventional mini percutaneous nephrolithotomy in patients with Escherichia coli bacteriuria.

To evaluate the safety and efficacy of tubeless percutaneous nephrolithotomy (PCNL) in patients with Escherichia coli (E. coli) bacteriuria. We conducted a retrospective review of 84 patients with E. coli bacteriuria who underwent PCNL. Patients were divided into two groups according to whether a nephrostomy tube is placed at the end of the procedure. Preoperative clinical data, surgical outcomes, and postoperative complications were compared. Then, regression analysis of factors predicting success rate of PCNL in patients with E. coli bacteriuria was performed. After PCNL, residual fragments ≤ 4 mm were considered as success. At baseline, the two groups were similar with regard to age, gender, BMI, underlying disease, hydronephrosis, stone characteristics, and urinalysis. Postoperative fever occurred in 1 patient (3.8%) in the tubeless PCNL group, and in 5 patients (8.6%) in the conventional PCNL group (p > 0.05). There were no significant differences in terms of successful rate, decrease in hemoglobin, pain scores, blood transfusion, and hospitalization expenses. However, the tubeless PCNL group had significantly shorter operative time (60 vs. 70 min, p = 0.033), indwelling time of catheter (2 vs. 4 days, p < 0.001), and hospital stays (3 vs. 5 days, p < 0.001) than the conventional PCNL group. In the analysis of factors predicting success, the stone diameter, stone burden, and operative time were associated with success rate of PCNL. It is safe and effective to perform tubeless PCNL in patients with E. coli bacteriuria. Compared to conventional PCNL, tubeless PCNL accelerates patient recovery and shortens hospital stays.

Evaluation of erector spinae plane block in patients undergoing percutaneous nephrolithotomy in terms of postoperative pain reduction and patient satisfaction.

OBJECTIVES: Intravenous opioids and local anesthetic infiltrations are traditionally used to relieve postoperative pain. With developments in the field of regional anesthesia, several methods are now available for postoperative analgesia. This study aimed to investigate the efficacy of the erector spinae plane block (ESPB) in reducing both intraoperative opioid consumption and postoperative analgesic use in patients undergoing percutaneous nephrolithotomy (PCNL). METHODS: A total of 60 patients who underwent PCNL were divided into two groups: 30 patients who received ESPB (Group I) and 30 patients in the control group (Group II). Intraoperative and postoperative opioid usage were recorded for both groups. The pain levels of the patients were evaluated using visual analog scale (VAS) scores obtained at 1, 3, 6, 12, and 24 hours postoperatively. Postoperative satisfaction of the patients in both groups was also questioned and compared. RESULTS: A significant difference was detected between Group I and Group II patients in terms of intraoperative opioid require-ments (p=0.00), analgesic requirements in the first 24 hours postoperatively (p=0.00), patient satisfaction status (p=0.00), and VAS scores obtained at 0, 3, 6, and 12 hours postoperatively. No significant difference was found in VAS scores at the 24th postoperative hour. CONCLUSION: ESPB is a simple, convenient technique that can be performed under ultrasound guidance. It provides remarkable postoperative analgesia and satisfaction in patients undergoing PCNL.

Intraoperative computed tomography for detection of residual stones in endourology procedures: systematic review and meta-analysis.

BACKGROUND: Success rates in endourological procedures, notably percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS), have demonstrated suboptimal outcomes, leading to more reinterventions and radiation exposure. Recently, the use of intraoperative computed tomography (ICT) scans has been hypothesized as a promising solution for improving outcomes in endourology procedures. With this considered, we conducted a comprehensive systematic review and meta-analysis encompassing all available studies that evaluate the impact of the use of intraoperative CT scans on surgical outcomes compared to conventional fluoroscopic-guided procedures. METHODS: This systematic review was conducted in accordance with PRISMA guidelines. Multiple databases were systematically searched up to December of 2023. This study aimed to directly compare the use of an ICT scan with the standard non-ICT-guided procedure. The primary endpoint of interest was success rate, and the secondary endpoints were complications and reintervention rates, while radiation exposure was also evaluated. Data extraction and quality assessment were performed following Cochrane recommendations. Data was presented as an Odds ratio with 95%CI across trials and a random-effects model was selected for pooling of data. RESULTS: A comprehensive search yielded 533 studies, resulting in the selection of 3 cohorts including 327 patients (103 ICT vs 224 in non-ICT). Primary outcome was significantly higher in the experimental group versus the control group (84.5% vs 41.4% respectively, 307 patients; 95% CI [3.61, 12.72]; p<0.00001; I2=0). Reintervention rates also decreased from 32.6% in the control to 12.6% in the ICT group (OR 0.34; 95%CI [0.12,0.94]; p =0.04; I2= 48%), whereas complication rates did not exhibit significant differences. Radiation exposure was also significantly reduced in two of the included studies. CONCLUSION: This meta-analysis highlights a favorable outcome with intraoperative CT scan use in PCNL procedures, showing a considerable increase in SFR when compared to standard fluoroscopy and nephroscopy. Despite limited studies, our synthesis underscores the potential of ICT scans to significantly reduce residual stones and their consequences for endourology patients, as reinterventions and follow-up ionizing radiation studies.

Prone vs supine percutaneous nephrolithotomy: does position affect renal pelvic pressures?

The purpose of this study was to measure and compare renal pelvic pressure (RPP) between prone and supine percutaneous nephrolithotomy (PCNL) in a benchtop model. Six identical silicone kidney models were placed into anatomically correct prone or supine torsos constructed from patient CT scans in the corresponding positions. A 30-Fr renal access sheath was placed in either the upper, middle, or lower pole calyx for both prone and supine positions. Two 9-mm BegoStones were placed in the respective calyx and RPPs were measured at baseline, irrigating with a rigid nephroscope, and irrigating with a flexible nephroscope. Five trials were conducted for each access in both prone and supine positions. The average baseline RPP in the prone position was significantly higher than the supine position (9.1 vs 2.7 mmHg; p < 0.001). Similarly, the average RPP in prone was significantly higher than supine when using both the rigid and flexible nephroscopes. When comparing RPPs for upper, middle, and lower pole access sites, there was no significant difference in pressures in either prone or supine positions (p > 0.05 for all). Overall, when combining all pressures at baseline and with irrigation, with all access sites and types of scopes, the mean RPP was significantly higher in the prone position compared to the supine position (14.0 vs 3.2 mmHg; p < 0.001). RPPs were significantly higher in the prone position compared to the supine position in all conditions tested. These differences in RPPs between prone and supine PCNL could in part explain the different clinical outcomes, including postoperative fever and stone-free rates.

Bilateral Single-session PCNL with Minimally Invasive Technique in Pediatric Nephrolithiasis.

PURPOSE: To assess outcomes of bilateral single-session percutaneous nephrolithotomy (PCNL) with minimally invasive techniques in pediatric population. MATERIALS AND METHODS: From August 2015 to July 2021, 45 children (including 12 infants) were treated with bilateral single-session PCNL, which included miniPCNL (12-16-Fr) and Microperc (4.8-Fr). Patient, stone and operation-related characteristics, stone-free rate (SFR) and complication rate (CR) were compared using ANOVA. Independent predictors were determined using multivariate linear regression. RESULTS: The mean stone burden was 3.2 cm in sum diameter for both kidneys. For bilateral kidneys, the mean operative time was 61.6min and SFR was 93.3%; CR was 53.3%, of which complications of Clavien grade 1 and 2 accounted for 46.7%. Bilateral Microperc, bilateral miniPCNL and Microperc plus miniPCNL was performed in 19, 14 and 12 children respectively. Both irrigation volume and postoperative stay were less in groups with Microperc. Both SFRs and CRs were satisfactory for the three groups. Self-limiting hematuria represented the most common complication of all cases (33.3%), especially in groups with miniPCNL. The stone burden was the only independent predictor for operative time (P < .001) and the postoperative complication (P = .008). Children with older age (P = .009), higher body mass index (P = .016) or a higher stone burden (P < .001) received larger irrigated fluid volume. Microperc was associated with less irrigated fluid volume (P = .001). Children with Clavien grade 3 complications (P = .004) spent prolonged postoperative hospital stay. CONCLUSION: With favourable SFR and acceptable CR, bilateral single-session PCNL with minimally invasive techniques might be an effective and safe procedure for pediatric nephrolithiasis.

A retrospective cohort study: evaluating the efficacy of standard versus tubeless percutaneous nephrolithotomy (PCNL) in pediatric patients up to 18 years old.

Percutaneous nephrolithotomy (PCNL) is an endourological method applied as the standard or tubeless method for kidney stone treatment. In a retrospective cohort study, 88 surgery units involving 75 children up to 18 years old with kidney stones who underwent the surgery for 8 years in Shahid Beheshti and Boo-ali hospitals in Hamadan with one of the two methods of standard or tubeless PCNL were evaluated and compared considering the success rate of operation, hemoglobin, hematocrit drop, need for medications, need for blood transfusion, duration of surgery, and the length of hospital stay. Among the 88 units studied, 47 cases were operated with the standard PCNL and 41 cases by tubeless method. In children operated by standard and tubeless PCNL, the complete success rate of operation was 87.2% and 100% (P = 0.006), the need for blood transfusion was 2.1% and 0% (P = 1.00), the need for opioids was 27.7% and 14.6% (P = 0.134), the decrease in hemoglobin was - 1.82 ± 0.94 and -1.30 ± 0.98 mg/dl (P = 0.024), the decrease in hematocrit was - 5.40 ± 2.66 and -3.52 ± 3.11 mg/dL (P = 0.003), the mean surgery duration was 109.30 ± 53.27 and 101.46 ± 31.92 min (P = 0.414), the duration of postoperative hospitalization was 3.38 ± 1.76 and 2.46 ± 1.27 days (P = 0.007), and the frequency of fever was 23.4% and 7.3% (P = 0.04), respectively. The success rate of kidney stone surgery in children with the tubeless PCNL is higher than the standard method, and its complications are lower.

PCNL vs. two staged RIRS for kidney stones greater than 20 mm: systematic review, meta-analysis, and trial sequential analysis.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) is considered the gold standard treatment for kidney stones greater than 20 mm. However, retrograde intrarenal surgery (RIRS) may achieve the same stone-free rate with repeated procedures, and potentially fewer complications. This study aimed to compare the efficacy and safety of PCNL and two-staged RIRS. EVIDENCE ACQUISITION: We conducted a systematic search in PubMed, Embase, Scopus, Cochrane, and Web of Science for studies comparing PCNL and RIRS for kidney stones greater than 20mm. The primary outcome is stone-free rate (SFR) of PCNL and RIRS (repeated once if needed). Secondary outcomes were SFR of PCNL versus RIRS (single procedure), operative time, hospital stay, need for auxiliary procedures, and complications. We performed a subgroup analysis for randomized trials, non-randomized trials, and patients with solitary kidney. We performed a trial sequential analysis for the main outcome. EVIDENCE SYNTHESIS: We included 31 articles, with 1987 patients in the PCNL and 1724 patients in RIRS. We confirmed the traditional result that after a single procedure PCNL has a higher SFR. We also found that comparing the SFR of PCNL and RIRS, repeated up to two times if needed, no difference in SFR was observed. Surprisingly, only 26% (CI95 23%-28%) of the patients required a second RIRS. In the trial sequential analysis, the last point of the z-curve was within futility borders. We observed that PCNL has a higher incidence of complications (RR=1.51; CI95 1.24, 1.83; P<0.0001; I2=28%), specifically CD2 (RR=1.82; CI95 1.30, 2.54; P=0.0004; I2=26%) and longer hospital stay (MD 2.57; 2.18, 2.96; P<0.00001; I2-98%). No difference was observed regarding operative time. CONCLUSIONS: RIRS repeated up to two times is equivalent to PCNL in terms of the SFR and may have the same safety.

Risk of Systemic Inflammatory Response Syndrome Following Preoperative Glucocorticoids Administration in Patients After Percutaneous Nephrolithotomy: A Retrospective Cohort Study.

INTRODUCTION: Systemic inflammatory response syndrome (SIRS) is one of the most serious complications in patients undergoing percutaneous nephrolithotomy (PCNL). Although glucocorticoids are increasingly used during PCNL, few studies have been concerned about the association between glucocorticoids and postoperative SIRS. The study aims to explore whether preoperative use of glucocorticoids is associated with SIRS after PCNL. METHODS: A total of 1259 patients who underwent PCNL between January 2015 and April 2021 were enrolled in the retrospective cohort study. Risk factors for post-PCNL SIRS were identified by univariate and multivariate regression analysis. To further explore the association between preoperative administration of glucocorticoids and SIRS, 113 pairs of patients were matched for the confounding factors using propensity score matching (PSM) analysis. The odds ratios (OR) and 95 % confidence intervals (CI) for the above variables were analyzed. RESULTS: The incidence of SIRS after PCNL was 9.6 % (121/1259) and the patients who suffered from postoperative SIRS had longer hospital stays and higher hospital costs (all p < 0.05). Multivariate logistic regression analysis indicated that female, preoperative leukocyte count, insertion of central vein catheter, serum albumin, preoperative high-sensitive C-reactive protein/albumin ratio, preoperative transfusion, preoperative administration of glucocorticoids were independent risk factors for SIRS (all p < 0.05). After minimization, the effects of confounding factors by PSM, preoperative administration of glucocorticoids was significantly correlated with SIRS in patients after PCNL (OR=2.44, 95 %CI: 1.31-4.55, p = 0.005). CONCLUSION: Preoperative administration of glucocorticoids is an independent risk factor for SIRS in patients undergoing PCNL.

Systemic inflammatory response syndrome (SIRS) is a frequent and severe complication in patients underwent percutaneous nephrolithotomy (PCNL), which can be challenging to diagnose early, potentially leading to delayed treatment. Identifying SIRS risk factors and promptly treating high-risk patients is crucial. Glucocorticoids are commonly used to prevent SIRS in clinical practice, and this study aims to investigate whether preoperative glucocorticoid administration is associated with SIRS after PCNL. In total, 1259 patients underwent PCNL and were enrolled in the study. The study utilized both propensity score matching (PSM) analysis and regression analysis to identify risk factors for post-PCNL SIRS. The incidence of SIRS after PCNL was 9.6 % in the study and patients with postoperative SIRS had longer hospital stays and higher hospital costs. After minimizing the potential influence of confounding factors through the use of PSM, we found a significant association between the preoperative use of glucocorticoids and the occurrence of SIRS in patients undergoing PCNL. Based on our analysis, we can conclude that the preoperative administration of glucocorticoids represents an independent risk factor for the development of SIRS in these patients.

Transient ureteral obstruction after mini-percutaneous nephrolithotomy is associated with stone volume and location: results from a single-center, real-life study.

PURPOSE: To evaluate the rate of and predictors of ureteral obstruction after mini-percutaneous nephrolithotomy (mPCNL) for kidney stones. METHODS: We analyzed data from 263 consecutive patients who underwent mPCNL at a single tertiary referral academic between 01/2016 and 11/2022. Patient's demographics, stone characteristics, and operative data were collected. A nephrostomy tube was placed as the only exit strategy in each procedure. On postoperative day 2, an antegrade pyelography was performed to assess ureteral canalization. The nephrostomy tube was removed if ureteral canalization was successful. Descriptive statistics and logistic regression models were used to identify factors associated with a lack of ureteral canalization. RESULTS: Overall, median (IQR) age and stone volume were 56 (47-65) years and 1.7 (0.8-4.2) cm3, respectively. Of 263, 55 (20.9%) patients showed ureteral obstruction during pyelography. Patients without ureteral canalization had larger stone volume (p < 0.001), longer operative time (p < 0.01), and higher rate of stones in the renal pelvis (p < 0.01) than those with normal pyelography. Length of stay was longer (p < 0.01), and postoperative complications (p = 0.03) were more frequent in patients without ureteral canalization. Multivariable logistic regression analysis revealed that stone volume (OR 1.1, p = 0.02) and stone located in the renal pelvis (OR 2.2, p = 0.04) were independent predictors of transient ureteral obstruction, after accounting for operative time. CONCLUSION: One out of five patients showed transient ureteral obstruction after mPCNL. Patients with a higher stone burden and with stones in the renal pelvis are at higher risk of inadequate ureteral canalization. Internal drainage might be considered in these cases to avoid potential complications.

Construction and validation of the nomogram predictive model for post-percutaneous nephrolithotomy urinary sepsis.

OBJECTIVE: This study aimed to construct and validate a simple and accurate clinical nomogram for predicting the occurrence of post-percutaneous nephrolithotomy sepsis, aiming to assist urologists in the early identification, warning, and early intervention of urosepsis, and to provide certain evidence-based medicine basis. METHODS: This study included patients who underwent PCNL surgery due to kidney or upper ureteral stones at the Department of Urology, Affiliated Hospital of Zunyi Medical University, from January 2019 to September 2022. This study utilized univariate and multivariate logistic regression analysis to screen and evaluate the risk factors for sepsis and construct a predictive model. An evaluation was performed using the receiver operating characteristic curve, calibration curve, and decision curve analysis curve. All statistical analyses were conducted using R version 4.2. RESULTS: A total of 946 patients who underwent post-PCNL were included in this study, among whom 69 patients (7.29%) developed post-PCNL urinary sepsis. Multiple-factor logistic regression analysis identified four independent risk factors associated with post-PCNL urinary sepsis, including positive urinary nitrite (OR = 5.9, P < 0.001), positive urine culture (OR = 7.54, P < 0.001), operative time ≥ 120 min (OR = 20.93, P = 0.0052), and stone size ≥ 30 mm (OR = 13.81, P = 0.0015). The nomogram model demonstrated good accuracy with an AUC value of 0.909, and in the validation cohort, the AUC value was 0.922. The calibration curve indicated a better consistency between the predictive line chart and the actual occurrence of post-PCNL urinary sepsis. The decision curve analysis curve showed favorable clinical utility. CONCLUSION: Preoperative positive urine culture, positive urinary nitrite, operative time ≥ 120 min, and stone size ≥ 30 mm are independent risk factors for developing post-PCNL urinary sepsis. The constructed line chart based on these factors effectively assesses the risk of urinary sepsis in patients after PCNL.

Evaluation of Factors Influenced on the Effectiveness of Percutaneous Nephrolithotomy.

Background: Generally, there are many methods for the treatment of urinary stones, of which percutaneous nephrolithotomy (PCNL) is a minimally invasive and highly effective method, and now become the first-line management for urinary stones, especially in the cases of complex stones and staghorne calculi. Accurate assessment of stone location, stone morphology, degree of hydronephrosis as well as urinary system abnormalities is extremely important in the percutaneous nephrolithotomy strategy. Objective: The aim of this study was to evaluate the S.T.O.N.E score as well as other factors that influenced the effectiveness of PCNL. Methods: Descriptive study on 71 patients with kidney stones, who underwent multi-slice CT scan of the urinary system before PCNL and then PCNL at Hanoi Medical University Hospital from July 2022 to July 2023. All patients received the informed consent and agreed to participate in the study. The factors included the stone area, the track length (from the skin surface to the stone central), the degree of urinary tract dilatation, the number of involved calyces, the density of stone, the renal parenchyma thickness, the ureteral wall thickness and fat infiltration measured on MSCT non-contrast phase. These factors were used to predict the effectiveness of PCNL including the stone clearance rate (SCR) and the operation time. Results: The mean age of the patient group was 53.8±12.3. The male/female ratio was 1.54. There was a significant difference (p<0.05) between the following factors and the operation time: the stone area (<400, 400-799, 800-1599 and >1600 mm2), the degree of urinary tract dilatation (no or might and moderate or severe dilatation), the number of involved calyces (≤ 2, 3 and staghorne calculi), the renal parenchyma thickness (<18 mm and ≥18mm). In contrast, there were no significant differences between the following factors and the surgery time (p>0.05): the track length (<100 and ≥100 mm), and the stone density (<950 and ≥950 HU). Regarding the S.T.O.N.E score (included five factors: Size, Track length, Obstruction, Number of involved calyces, and Evaluation of stone density), there was a strong correlation between S.T.O.N.E score and the surgery time (p<0.001, r=0.94), and the SCR (p=0.001, r=-0.97). Conclusion: The evaluation of these factors played an important role in the prediction of the effectiveness of PCNL.

What should the optimal access site be for percutaneous treatment of anterior lower pole calyx stones?

OBJECTIVES: Compared to other stone groups, anterior calyx stones are more challenging for endourologists to treat. This study aims to evaluate the differences between our latest technique and conventional techniques for treating anterior calyx stones in the lower pole. MATERIALS AND METHODS: Patients with isolated anterior lower pole calyx or complex lower pole stones with anterior calyx branching were included in the study. The first group included lower pole access, while the second group included percutaneous treatment through the middle or upper pole. In the first group, the posterior calyx or direct anterior calyx approach was utilised depending on whether the stone was isolated calyx, complex structure or calyx anatomy, while in the second group, percutaneous nephrolithotomy was performed through the middle or upper pole posterior calyx access. RESULTS: There were 37 patients in Group 1 and 25 patients in Group 2. Both groups were similar regarding patient age, sex, stone burden, and stone localisation (p > 0.05). When comparing operative and post-operative data between groups, it was found that the stone clearance rate, number of accesses, and haematocrit decrease were statistically superior in the second group (p: 0.003, p: 0.002, p: 0.018), with no significant difference in mean operative time, length of hospital stay, fluoroscopy time and pain score (p > 0.05). CONCLUSIONS: Percutaneous surgery utilising an access from a calyx distal to the stone may offer better clearance and lower morbidity rates for lower pole stones involving the anterior calyx.

Feasibility of stereotactic optical navigation for needle positioning in percutaneous nephrolithotomy.

BACKGROUND: This study assessed the feasibility of acquiring single-attempt access to the pelvicalyceal system during percutaneous nephrolithotomy (PCNL) using stereotactic optical navigation combined with cone-beam CT (CBCT) imaging. METHODS: Patients with a PCNL indication were prospectively included in this IRB approved study. After sterile preparation, fiducial markers were attached to patients' skin. An initial intraprocedural CBCT scan was acquired, on which the urologist planned the needle trajectory using the navigation software. After verifying that no critical structures were crossed, the needle guide was aligned with the plan. A needle was manually inserted through the needle guide to the indicated depth and a second CBCT scan was performed for needle position confirmation. Both, scanning and needle insertion, were performed under apnea. The study evaluated technical success, accuracy, procedure time, complication rate, and radiation dose. RESULTS: Between June 2022 and April 2023, seven patients were included. In all patients, the navigation system allowed safe puncture. However, the technical success rate was only 29%. In 42% of the cases, pelvicalyceal access was achieved by a small manual adjustment. In the remaining 29%, the needle was retracted and positioned per clinical standard. The average deviation between the needle and target was 5.9 ± 2.3 mm. The average total procedure time was 211 ± 44 min. The average radiation exposure was 6.4 mSv, with CBCT scanning contributing to 82% of this exposure. CONCLUSIONS: The optical navigation system facilitated safe needle insertion but did not consistently ensure accurate one-attempt needle positioning for PCNL. Real-time visualization and trajectory correction may improve the technical success rate.

Is supine a preferred position for percutaneous nephrolithotomy in the pediatric age group? A randomized controlled study.

BACKGROUND: The aim is to evaluate supine versus prone position in mini-percutaneous nephrolithotomy in pediatric renal urolithiasis management. METHODS: A randomized controlled trial was constructed to evaluate supine versus prone position in pediatric PCNL. Seventy pediatric patients with a stone burden ≥1.5 cm were randomized into two groups. RESULTS: Sixty-three patients were available for evaluation in our study with no significant difference in the perioperative demographic data. The supine group showed a shorter operation time of 43.9 min compared to 73.5 min in the prone group. The stone-free rate was higher in the supine group, with a 93.9% SFR compared to 83.3% in the prone group. The supine group showed a shorter hospital stay of 2.0±1.0 days, compared to 3.20±1.56 days in the prone group. No significant difference was seen in the perioperative complication rate and fluoroscopy time between both groups. CONCLUSIONS: Supine mini-percutaneous nephrolithotomy is safe and effective in managing pediatric renal stones, with a higher stone-free rate, less operative time, and less hospital stay compared to the prone position.

Comparison of lithotripsy methods during mini-PNL: is there a role for ballistic lithotripsy in the era of high-power lasers.

BACKGROUND: For renal stones > 20 mm, percutaneous nephrolithotomy (PNL) offers the best stone clearance rates with acceptable complication rates. This study aimed to compare the efficiency of high-power holmium YAG laser and ballistic lithotripsy during mini-PNL. METHODS: Data from 880 patients who underwent mini-PNL for renal stones was investigated retrospectively. The study utilized propensity score matching to create two groups: laser lithotripsy (n = 440) and ballistic lithotripsy (n = 440). The groups were matched based on stone size, Guy's stone score, and stone density. The main objectives of the study were to assess the stone-free rate (SFR), duration of surgery, and complication rates. RESULTS: The average age of the population was 51.4 ± 7.1 years, with a mean stone size of 28.6 ± 8.3 mm and a mean stone density of 1205 ± 159 HU. There were no significant differences between the groups. The SFRs of the laser lithotripsy and ballistic lithotripsy were 92.5% and 90.2%, respectively (p = 0.23). The laser lithotripsy group had a notably shorter surgery time (40.1 ± 6.3 min) compared to the ballistic lithotripsy group (55.6 ± 9.9 min) (p = 0.03). Complication rates were similar (p = 0.67). CONCLUSIONS: Our study shows that a high-power holmium YAG laser provides quicker operation time compared to ballistic lithotripsy. However, ballistic lithotripsy is still an effective and safe option for stone fragmentation during mini-PNL. In places where a high-power holmium YAG laser is not available, ballistic lithotripters are still a safe, effective, and affordable option for mini-PNL.

Vacuum-assisted mini-percutaneous nephrolithotomy is associated with lower rates of infectious complications compared to vacuum-cleaner procedure in patients at high risk for infections: a single-center experience.

PURPOSE: To evaluate the impact of vacuum-assisted mini-percutaneous nephrolithotomy (vamPCNL) vs. vacuum-cleaner mPCNL (vcmPCNL) on the rate of postoperative infectious complications in a cohort of patients with high risk factors for infections. METHODS: We retrospectively analysed data from 145 patients who underwent mPCNL between 01/2016 and 12/2022. Patient's demographics, stones characteristics and operative data were collected. vamPCNL and vcmPCNL were performed based on the surgeon's preference. High-risk patients were defied as having ≥ 2 predisposing factors for infections such as a history of previous urinary tract infections, positive urine culture before surgery, stone diameter ≥ 3 cm, diabetes mellitus and hydronephrosis. Complications were graded according to modified Clavien classification. Descriptive statistics and logistic regression models were used to identify factors associated with postoperative infectious complications. RESULTS: vamPCNL and vcmPCNL were performed in 94 (64.8%) and 51 (35.2%) cases, respectively. After surgery, infectious complications occurred in 43 (29.7%) participants. Patients who developed infectious complications had larger stone volume (p = 0.02) and higher rate of multiple stones (p = 0.01) than those who did not. Infectious complications occurred more frequently after vcmPCNL than vamPCNL (55.9% vs. 44.1%. p = 0.01) in high-risk patients. Longer operative time (p < 0.01) and length of stay (p < 0.01) were observed in cases with infectious complications. At multivariable logistic regression analysis, longer operative time (OR 1.1, p = 0.02) and vcmPCNL (OR 3.1, p = 0.03) procedures were independently associated with the risk of infectious complications post mPCNL, after accounting for stone volume. CONCLUSION: One out of three high-risk patients showed infectious complications after mPCNL. vamPCL and shorter operative time were independent protective factors for infections after surgery.

Postoperative antibiotic prophylaxis for percutaneous nephrolithotomy and risk of infection: a systematic review and meta-analysis.

PURPOSE: The aim of this study is to perform a high-quality meta-analysis using only randomized controlled trials (RCT) to better define the role of postoperative antibiotics in patients undergoing percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: A literature search for RCTs in EMBASE, PubMed, and Web of Science up to May 2023 was conducted following the PICO framework: Population-adult patients who underwent PCNL; Intervention-postoperative antibiotic prophylaxis until nephrostomy tube withdrawal; Control-single dose of antibiotic during the induction of anesthesia; and Outcome-systemic inflammatory response syndrome (SIRS) or sepsis and fever after PCNL. The protocol was registered on the PROSPERO database (CRD42022361579). We calculated odds ratios (OR) and 95% confidence intervals (CI). A random-effects model was employed, and the alpha risk was defined as < 0.05. RESULTS: Seven articles, encompassing a total of 629 patients, were included in the analysis. The outcome of SIRS or sepsis was extracted from six of the included studies, while the outcome of postoperative fever was extracted from four studies. The analysis revealed no statistical association between the use of postoperative antibiotic prophylaxis until nephrostomy tube withdrawal and the occurrence of SIRS/sepsis (OR 1.236, 95% CI 0.731 - 2.089, p=0.429) or fever (OR 2.049, 95% CI 0.790 - 5.316, p=0.140). CONCLUSION: Our findings suggest that there is no benefit associated with the use of postoperative antibiotic prophylaxis until nephrostomy tube withdrawal in patients undergoing percutaneous nephrolithotomy (PCNL). We recommend that antibiotic prophylaxis should be administered only until the induction of anesthesia in PCNL.

The significance of clinically insignificant residual fragments after percutaneous nephrolithotomy: an analysis into the relevance of complete stone clearance.

PURPOSE: After treatment for kidney stones, residual fragments with a diameter of ≤ 4 mm are traditionally referred to as 'clinically insignificant residual fragments'. We hypothesize that patients with these fragments are at an increased risk for stone-related morbidity, such as complaints, hydronephrosis, and stone regrowth, when compared to stone-free patients. This study aimed to investigate the relevance of complete stone clearance in surgical treatment of urolithiasis. METHODS: We conducted a single-center retrospective cohort study. Patients who underwent percutaneous nephrolithotomy between 2015 and 2020 were included if a CT-scan was available within 6 months after the procedure, and the follow-up duration was at least 1 year. The stone-free status at the end of the first stone episode during the study period was categorized as fully stone-free, not stone-free with small residual fragments (≤ 4 mm) and not stone-free with large residual fragments (> 4 mm). Follow-up data were collected, including stone-related events and re-intervention rates. RESULTS: A total of 103 subjects were included with a median follow-up of 21.4 months. Stone-related events occurred in 10 (29.4%) of the fully stone-free subjects, 20 (58.8%) of the subjects with small residual fragments and 25 (71.4%) of the subjects with large residual fragments. The stone-related event-free survival per subgroup resulted in a significantly different survival distribution in a log rank test (p = 0.008). CONCLUSION: A complete stone-free status seems to be of fundamental importance for decreasing stone-related morbidity. Further developments and research should focus on optimizing the full clearance of stone material during PCNL.