Initial Clinical Experience With a Novel Robotically Assisted Platform for Combined Mini-Percutaneous Nephrolithotomy and Flexible Ureteroscopic Lithotripsy.

PURPOSE: We sought to evaluate the technical feasibility of performing a combined robotically assisted mini-percutaneous nephrolithotomy (PCNL) and flexible ureteroscopy (URS) procedure by a single urologist using the MONARCH Platform, Urology (Johnson & Johnson MedTech, Redwood City, California). MATERIAL AND METHODS: In this prospective, first-in-human clinical trial, 13 patients underwent robotically-assisted PCNL for renal calculi at the University of California-Irvine, Department of Urology. Successful completion of the procedure was assessed as the primary endpoint. Postoperative adverse events were monitored for 30 days following the completion of the procedure. Stone ablation efficiency was evaluated on postoperative day 30 with low-dose 2-3 mm slice CT scans. Patients were classified according to the maximum length of their residual stone fragments as either absolute stone-free (Grade A), < 2 mm remnants (Grade B), or 2.1-4.0 mm remnants (Grade C). RESULTS: The combined robotic mini-PCNL and URS procedure was successfully completed in 12 of 13 procedures. No robotic device-related adverse events occurred. Preoperative stone burden was quantified by both maximum linear measurement (median 32.8 mm) as well as by CT-based volume (median 1645.9 mm3). Using the unique robotically assisted targeting system, percutaneous access was gained directly through the center of the renal papilla in a single pass in all cases. Median operative time was 187 minutes (range: 83-383 minutes). On postoperative day 30, a 98.7% (range: 72.9%-100.0%) volume reduction was achieved, with 5 Grade A (38.5%), 1 Grade B (7.7%), and 2 Grade C (15.4%). Three patients experienced complications (2 grade 1 and one grade 2 Clavien-Dindo). CONCLUSIONS: Our preliminary investigation demonstrates the safety, efficacy, and feasibility of a unique robotic-assisted combined mini-PCNL and URS platform.

Tranexamic acid for percutaneous nephrolithotomy: an abridged Cochrane review.

OBJECTIVE: To assess the effects of tranexamic acid (TXA) in individuals with kidney stones undergoing percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: We performed a literature search of Cochrane Library, PubMed (including MEDLINE), Embase, Scopus, Global Index Medicus, trials registries, grey literature, and conference proceedings. We included randomised controlled trials (RCTs) that compared treatment with PCNL with administration of TXA to placebo (or no TXA) for patients aged ≥18 years. Two review authors independently classified studies and abstracted data. Primary outcomes were blood transfusion, stone-free rate (SFR), thromboembolic events (TEE). We rated the certainty of evidence (CoE) according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach using a minimally contextualised approach with pre-defined thresholds for minimally clinically important differences (MCID). RESULTS: We included 10 RCTs assessing the effect of systemic TXA in PCNL vs placebo (or no TXA). Eight studies were published as full text. Based on an adjusted baseline risk of blood transfusion of 5.7%, systemic TXA may reduce blood transfusions (risk ratio [RR] 0.45, 95% confidence interval [CI] 0.27-0.76). Based on an adjusted baseline SFR of 75.7%, systemic TXA may increase SFR (RR 1.11, 95% CI 0.98-1.27). There is probably no difference in TEEs (risk difference 0.001, 95% CI -0.01 to 0.01). Systemic TXA may increase adverse events (AEs) (RR 5.22, 95% CI 0.52-52.72). Systemic TXA may have little to no effect on secondary interventions (RR 1.15, 95% CI 0.84-1.57). The CoE for most outcomes was assessed as low or very low. CONCLUSIONS: Based on a body of evidence of 10 RCTs, we found that systemic TXA in PCNL may reduce blood transfusions, major surgical complications, and hospital length of stay, as well as improve the SFR; however, it may increase AEs. These findings should inform urologists and their patients in making informed decisions about the use of TXA in the setting of PCNL.

Percutaneous nephrolithotomy vs retrograde intrarenal surgery for renal stones: a Cochrane Review.

OBJECTIVES: To assess the effects of percutaneous nephrolithotomy (PCNL) vs retrograde intrarenal surgery (RIRS) for the treatment of renal stones in adults. METHODS: We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, three other databases, trials registries, other sources of the grey literature, and conference proceedings up to 23 March 2023. We applied no restrictions on publication language or status. Screening, data extraction, risk-of-bias assessment, and certainty of evidence (CoE) rating using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach were done in duplicate by two independent reviewers. This co-publication focuses on the primary outcomes of this review only. RESULTS: We included 42 trials that met the inclusion criteria. Stone-free rate (SFR): PCNL may improve SFRs (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.08-1.18; I2 = 71%; 39 studies, 4088 participants; low CoE). Major complications: PCNL probably has little to no effect on major complications (RR 0.86, 95% CI 0.59-1.25; I2 = 15%; 34 studies, 3649; participants; moderate CoE) compared to RIRS. Need for secondary interventions: PCNL may reduce the need for secondary interventions (RR 0.31, 95% CI 0.17-0.55; I2 = 61%; 21 studies, 2005 participants; low CoE) compared to RIRS. CONCLUSION: Despite shortcomings in most studies that lowered our certainty in the estimates of effect to mostly very low or low, we found that PCNL may improve SFRs and reduce the need for secondary interventions while not impacting major complications. Ureteric stricture rates may be similar compared to RIRS. We expect the findings of this review to be helpful for shared decision-making about management choices for individuals with renal stones.

Exploring the competency of the comprehensive complication index over the clavien-dindo classification in standard percutaneous nephrolithotomy: a call for better complication reporting.

PURPOSE: The Comprehensive Complication Index (CCI) was introduced in 2013 to overcome the limitations of the Clavien-Dindo Classification (CDC) in grading postoperative complications. The objective of this study to assess the predictive value of the CDC and the CCI for postoperative course in patients undergoing standard adult percutaneous nephrolithotomy (PCNL). METHODS: A retrospective analysis of 320 renal units that underwent standard PCNL between July 2021 - April 2023 was conducted. The CDC and CCI systems assessed complications occurring within the first 30 days after surgery. A second CCI score was calculated only on the highest CDC grade, and this score was referred to as the noncumulative CCI. A comparative analysis was conducted to determine the predictive efficacy of both evaluation methods regarding the postoperative course. RESULTS: The postoperative complication rate was 23.1% (74/320). Eight patients (2.5%) experienced multiple complications, resulting in a higher total CCI score than the noncumulative CCI (p = 0.010). Correlation analysis revealed that the CCI correlated with the length of hospital stay (LOS) more precisely than the noncumulative CCI (CCI: r = 0.335; p = 0.004 vs. noncumulative CCI: r = 0.325; p = 0.005). Compared with patients with a single complication, those with multiple complications had similar demographics, preoperative stone characteristics, and intraoperative features. CONCLUSION: Cumulative CCI proves to be a more effective predictor of LOS and complication burden in standard PCNL than CDC. Hence, using CCI to evaluate complications after PCNL may be a more appropriate approach.

Risk factors and prediction model for postoperative complications in patients with struvite stones after percutaneous nephrolithotomy and flexible ureteroscopy.

OBJECTIVE: To analyze the risk factors for complications in patients with struvite stones following percutaneous nephrolithotomy (PCNL) or flexible ureteroscopy (fURS), and to establish a nomogram for postoperative complications in patients following PCNL. METHODS: A retrospective analysis was conducted on patients with struvite stones after PCNL and fURS at the Department of Urology, Peking University People's Hospital, from January 2012 to March 2022. The common pathogens and antimicrobial susceptibilities in preoperative midstream urine culture were analyzed. Logistic regression analyses were used to evaluate the risk factors. Receiver-operating characteristic (ROC) curve, calibration plots, and decision curve analysis (DCA) were used to assess the discrimination, accuracy, and practicability of the nomogram. RESULTS: 332 patients with struvite stones received one-stage PCNL or fURS, including 243 cases of PCNL and 89 cases of fURS. 72 patients (21.69%) developed postoperative complications. The most common pathogens in preoperative urine cultures were Escherichia coli, Proteus mirabilis, and Enterococcus faecalis. Multivariate logistic regression analysis showed that preoperative hemoglobin (OR = 0.981, P = 0.042), staghorn stone (OR = 4.226, P = 0.037), and positive preoperative midstream urine culture (OR = 2.000, P = 0.043) were independent risk factors for postoperative complications in patients following PCNL. The nomogram showed good performance in discrimination, accuracy, and applicability. CONCLUSION: Preoperative hemoglobin, staghorn stone, and positive preoperative midstream urine culture were independent risk factors for postoperative complications in patients with struvite stones following PCNL. A nomogram was developed to predict the probability of postoperative complications.

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.

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.

Ureteral stent after PCNL: is leaving the threads through the percutaneous tract safe and better tolerated?

OBJECTIVE: To assess safety, urinary symptoms, and feasibility of JJ stent removal with exteriorized threads through the percutaneous tract after percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: Prospective, transversal, comparative, experimental, randomized 1-to-1 cohort study in 52 patients who underwent "tubeless" PCNL from October 2020 to November 2022. Group A with threads through the urethra and Group B through the percutaneous tract. The validated USSQ (Ureteral Stent Symptom Questionnaire) was applied in the Urology office a week after the procedure, and the JJ stent was withdrawn by pulling the threads. Hemoglobin and urine culture, and pre- and post-surgery were evaluated. RESULTS: There is a statistically significant difference in favor of group B when comparing urinary symptoms (p = 0.008), body pain (p = 0.009), and general condition (p = 0.042), mainly for non-urgency incontinence, frequency of analgesic use, and dysuria. There were significant differences between groups (p = 0.028, p = 0.026, p = 0.027, respectively). There is no association with urinary infections (p = 0.603) nor an increased risk of bleeding (p = 0.321). CONCLUSION: The removal of the JJ stent with exteriorized threads through the percutaneous tract after PCNL in the office is a feasible and safe procedure if it is removed before 8 days and has better tolerance regarding the urinary symptoms.

Clinical study of UMP and RIRS in 1.0-2.0 cm diameter renal/upper ureteral calculi.

BACKGROUND: The purpose of this study was to compare the efficacy and safety of Ultra-mini-percutaneous nephrolithotomy (UMP) and Retrograde intrarenal surgery (RIRS) for renal/upper ureteral calculi in 1.0-2.0 cm diameter. METHODS: From October 2017 to October 2022, the surgical treatment of patients with renal/upper ureteral calculi in 1.0-2.0 cm diameter who were admitted to our hospital was retrospectively analyzed. They were divided into two groups, the UMP group (sixty-two cases) and the RIRS group (one hundred and nine cases), according to the different surgical methods. Baseline data includes general information, stone size, location, CT value, hydronephrosis, creatinine level, etc. RESULTS: Intraoperative blood loss was 33.6 ± 8.5 ml in the UMP group was significantly more than 4.3 ± 0.7 ml in the RIRS group (P < 0.05). Intraoperative renal pelvis pressure of UMP group 10.5 ± 1.3 mmHg was significantly lower than RIRS group 23.6 ± 5.6 mmHg (P < 0.05). The incidence of postoperative infection was higher in the RIRS group (thirteen cases [11.93%]), and one case ([1.61%]) in the UMP group (P < 0.05). Routine CT scans on the second day and two months after surgery showed that the stone clearance rates in the UMP group were 87.1% and 93.5%, respectively, higher than those in the RIRS group (69.7% and 79.8%, respectively; P < 0.05). CONCLUSION: UMP has the advantage of a higher stone-free rate but a higher risk of injury and bleeding. The advantages of RIRS include less trauma, less bleeding, and faster recovery, but lower stone-free rates and a higher risk of infection.

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.