Review of efficacy and safety of same-day discharge after percutaneous nephrolithotomy

PURPOSE

Prior literature reviews have assessed the efficacy and safety of outpatient percutaneous nephrolithotomy (PCNL) with "outpatient" defined as discharge within twenty-four hours of surgery. To our knowledge, this is the first literature review analyzing ambulatory PCNLs (aPCNL) defined as hospital discharge on the same day as surgery. This review aims to assess the efficacy and safety of same-day discharge after PCNL.

METHODS

We conducted a search in the PubMed database for key search terms including "ambulatory PCNL", "ambulatory percutaneous nephrolithotomy", "outpatient PCNL", "outpatient percutaneous nephrolithotomy", and "day surgery percutaneous nephrolithotomy". We reviewed articles defining "ambulatory" as discharge the same day the PCNL was performed. 13 papers were identified in our search.

RESULTS

Overall, we found no difference in complication rates, emergency department visits, and postoperative admissions when comparing outpatient PCNL to inpatient PCNL, and to previously published statistics for inpatient PCNL. Some studies even showed lower rates of adverse outcomes in ambulatory cohorts when compared to inpatient cohorts. Additionally, ambulatory PCNL conferred significant healthcare savings over inpatient PCNL.

CONCLUSION

This literature review suggests that ambulatory PCNL can be safely performed in both optimal and suboptimal surgical candidates with no significant increase in complications. Additional high-quality studies are warranted to further the evidence surrounding outpatient PCNL and its outcomes.

Drivers of calcium oxalate stone formation in the octogenarian population

INTRODUCTION

American Urological Association (AUA) guidelines suggest metabolic testing via 24-h urine studies in high-risk, interested first-time stone formers, and recurrent stone formers. If metabolic testing is not available or otherwise not feasible, clinicians may need to utilize empiric therapy. Debility and social barriers, particularly in the elderly population, may limit the practicality of metabolic testing, and therefore, empiric therapy is of particular importance. The aim of this study is to identify whether unique urinary metabolic abnormality profiles exist for octogenarians with calcium oxalate kidney stones, as this may guide empiric stone prevention therapy more precisely in this population.

MATERIALS AND METHODS

Patients with calcium oxalate stones from a single academic kidney stone center in New York, NY, were retrospectively identified in our prospectively managed database. Patient data, including demographic, clinical information, and baseline 24-h urine studies, were collected before initiating any treatment. Subjects were stratified by age (≤ 40, 41-59, 60-79, and ≥ 80 years) to compare the metabolic urinary abnormality profiles between octogenarians and other age groups. Subgroup analyses were also performed to compare results by gender and by the presence of underlying kidney dysfunction. Comparative statistical analysis was carried out using Chi-square tests, Mann-Whitney U tests, and t-tests where appropriate.

RESULTS

Hypocitraturia, low urine pH, and low urine volume were most common in older patients, particularly in octogenarians. Hypercalciuria, hypernatriuria, and hyperuricosuria were more apparent in younger groups.

CONCLUSION

With increasing age, hypocitraturia, low urine pH, and low urine volume were more prevalent on 24-h urine metabolic testing. We hypothesize increased comorbidity, including medical renal disease, polypharmacy, and dehydration are possible factors contributing to this unique profile. We suggest that empiric therapy targeted towards this profile is important in very elderly stone formers in whom 24-h urine testing may not be possible. Increased hydration, increased fruit and vegetable intake, and low-dose alkali therapy are easy measures to accomplish this.

Selecting an Endourology Society Fellowship Program: The Candidates' Perspectives

Introduction: Understanding the factors that influence the decision of urology residents to pursue an Endourology Society (ES) fellowship and the criteria used by applicants to rank programs may help residents and program directors (PDs) optimize the match process. In the present study, we surveyed current ES fellows to gain better insight surrounding their decision-making process. Materials and Methods: A survey was emailed to all ES fellows, comprising Endourology and Stone Disease (ESD), Laparoscopic and Robotic Surgery (MIS), and combination of ESD/MIS (COM) programs. A Likert scale ranging from 1 to 5 was used. The survey captured demographics such as geographic region, program type, duration, applicants' reasons for pursuing fellowship, criteria for ranking programs, and perceived improvements in surgical comfort levels at the end of their training. Results: Out of the 60 fellows who were surveyed, 40 (66.7%) responded. Among the respondents, 9 (22.5%) pursued ESD, 10 (25%) pursued MIS, and 21 (52.5%) pursued COM programs. The primary reason for seeking a fellowship was to improve surgical skills while increasing earning potential and enhancing research opportunities were deemed the least important. Fellows enrolled in 1-year programs were less likely to pursue fellowships for academic reasons. The two most significant factors in selecting a program were both related to gaining operative experience. Lastly, there was an increase in the level of comfort performing all endourological surgeries independently after fellowship. Conclusions: ES fellowship is seen as an opportunity to hone surgical skills and increase job competitiveness. When selecting a program, operative experience is the most important factor, and fellowship improves operative confidence. The information obtained from this study may mutually help guide future applicants and PDs in the decision process of the Endourology Match.

Comprehensive analysis of factors associated with significant blood loss during percutaneous nephrolithotomy

INTRODUCTION

The objective of this study is to conduct a thorough investigation of the risk factors associated with blood loss during PCNL, within the setting of a US urban tertiary care center.

MATERIALS AND METHODS

We conducted a retrospective analysis of our endourology database to identify adult patients who underwent PCNL for stone extraction at our tertiary stone center between October 2014 and December 2022. Patients were categorized into two groups based on the extent of blood loss: significant blood loss (SBL) and no significant blood loss (NSBL). The cut-off value for SBL was determined as the median change in hematocrit levels from preoperative to postoperative among patients who required postoperative transfusions. Several factors were evaluated, including stone dimensions, operative details, the presence of preoperative drains, patient position, type of access, access site, number of accesses, tract size, tract length, stone location, number of stones, operative time, and the S.T.O.N.E. Nephrolithometry Scoring System.

RESULTS

Our analysis included a total of 695 procedures performed on 674 distinct patients who met our inclusion criteria. Of these, 102 patients (14.7%) were included in the SBL group. Patients in the SBL group had a higher mean number of accesses (1.57 vs. 1.29, P<0.001), were positioned prone more often (96.0% vs. 88.6%, P = 0.025), and underwent fluoroscopic-guided access more frequently (89.9% vs. 64.8%, P<0.001). Additionally, significant differences were observed in stone morphology, with the SBL group having higher rates of complete staghorn stones (42.2% vs. 27.0%, P = 0.019) and lower rates of partial staghorn stones (27.7% vs. 36.8%, P = 0.019). A larger proportion of patients in the SBL group required a 16 French nephrostomy tube for postoperative drainage (13.3% vs. 10.4%, P = 0.041). Lastly, the SBL group had a longer mean operative time compared to the NSBL group (P<0.001). Multiple logistic regression analysis identified stone volume (P = 0.039), number of accesses (P = 0.047), and operative time (P = 0.006) as independent risk factors associated with SBL status.

CONCLUSION

Surgical complexity factors such as stone volume, number of accesses, and operative time are linked to a higher risk of SBL during PCNL. Stone volume and the requirement for multiple accesses can usually be estimated with reasonable accuracy before surgery.

Adjuvant intraluminal therapies for upper tract urothelial carcinoma

Upper urinary tract urothelial carcinomas (UTUCs) are often identified and first treated endoscopically. After proper risk stratification, adjuvant treatment may be recommended. Consequently, as adjuvant therapy becomes more common place in the oncological armamentarium, we seek to better characterize its existing and future therapeutic landscape. In this article, we present an overview of the most up-to-date information about intracavitary instillations as an adjuvant therapy in the context of UTUC. We reviewed the current literature on the epidemiology, disease characteristics, treatment, and outcomes of UTUC with a particularly focus on intraluminal adjuvant therapy for UTUC. This review provides a comprehensive overview of the most recent available data regarding adjuvant therapies used for UTUC. Intraluminal therapy plays an increasingly important role in the management of UTUC. Mitomycin C is the most common adjuvant treatment for UTUC with bacillus Calmette-Guerin (BCG) being utilized to a lesser extent. UGN-101 is a novel topical gel-based therapy that has shown promising results and thus recently garnered Food and Drug Administration (FDA) approval for UTUC. Other treatments such as BCG-IFN, gemcitabine, docetaxel, and drug-eluting stents (DES) may play a future role in UTUC treatment given further research. It is important to caveat that current studies on topical adjuvant treatments demonstrate varying degrees of effectiveness. This is largely due to limited research on UTUC, consisting of small sample sizes, and mostly retrospective experiences. Accordingly, further clinical trials are needed to evaluate the true benefit of these treatments.

The Role of Experience: How Case Volume and Endourology-Fellowship Training Impact Surgical Outcomes for Ureteroscopy

Introduction: Surgical experience is associated with superior outcomes in complex urologic cases, such as prostatectomy, nephrectomy, and cystectomy. The question remains whether experience is predictive of outcomes for less complex procedures, such as ureteroscopy (URS). Our study examined how case volume and endourology-fellowship training impacts URS outcomes. Methods: We retrospectively reviewed URS cases from 2017 to 2019 by high ureteroscopy volume urologists (HV), low ureteroscopy volume urologists (LV), endourology-fellowship trained (FT), and non-endourology FT (NFT) urologists. Surgical outcomes including stone-free rate (SFR), complication and reoperation rates, and postoperative imaging follow-up were analyzed between groups. Results: One thousand fifty-seven cases were reviewed across 23 urologists: 6 HV, 17 LV, 3 FT, and 20 NFT. Both FT and HV operated on more complex cases with lower rates of pre-stented patients. HV also operated on patients with higher rates of renal stones, lower pole involvement, and prior failed procedures. Despite this, FT and HV showed between 11.7% and 14.4% higher SFR, representing 2.7- to 3.6-fold greater odds of stone-free outcomes for primary and secondary stones. Additionally, HV and FT had a 4.9% to 7.8% lower rate of postoperative complications and a 3.3% to 4.3% lower rate of reoperations, representing 1.9- to 4.0-fold lower odds of complications. Finally, their patients had a 1.6- to 2.1-fold higher odds of postoperative imaging follow-up with a greater proportion receiving postoperative imaging within the recommended 3-month postoperative period. Conclusions: More experienced urologists, as defined by higher case volume and endourology-fellowship training, had higher SFR, lower complication and reoperation rates, and better postoperative imaging follow-up compared with less experienced urologists. Although less experienced urologists had outcomes in-line with clinical and literature standards, continued training and experience may be a predictor of better outcomes across multiple URS modalities.

Reverse Trendelenburg Positioning Minimizes Stone Retropulsion During Ureteroscopic Laser Lithotripsy: A Prospective Randomized Study

Purpose: Retropulsion of stone fragments during ureteroscopic laser lithotripsy (URSLL) remains a challenge for urologists and is associated with increased operative time and reduced stone-free rate (SFR). In this study, we compared the rate of retropulsion of ureteral stones during URSLL between the standard dorsal lithotomy (SDL) position and dorsal lithotomy position with reverse Trendelenburg (RT). Materials and Methods: Patients with ureteral stones requiring surgical intervention between May 2019 and January 2022 were randomized to undergo URSLL in either SDL or RT positions. The primary outcome of this study was stone retropulsion. Secondary outcomes included retropulsion to the kidney, SFR, operative time, 30-day emergency department visits and complications, and the need for conversion from semirigid to flexible ureteroscope. Differences between groups were evaluated using the chi-square test, Fisher exact test, Kruskal-Wallis test, or t-test. Results: A total of 114 patients were included in the study, with 57 patients in each group. There were no differences between groups in terms of baseline demographics or stone characteristics. Retropulsion was significantly less frequent in the RT group (68.4% vs 10.5%, p < 0.01). Similarly, the RT group was favored for lower risk of retropulsion into the kidney (40.4% vs 5.3%, p < 0.01), operative time (43.5 vs 33.0 minutes, p = 0.02), and need for ureteroscope conversion (16.7% vs 2.2%, p = 0.04). There was no difference in the SFR (100% vs 95%, p = 0.49). Conclusions: RT positioning during URSLL for ureteral stones significantly decreases the rate of stone retropulsion, operative time, and the need for conversion from semirigid to flexible ureteroscope.

The effects of continuing aspirin on blood loss and postoperative outcomes in percutaneous nephrolithotomy

BACKGROUND

Percutaneous nephrolithotomy (PCNL) is an effective surgery for complex kidney stones yet with inherent bleeding risks. It remains unclear whether aspirin should be discontinued prior to PCNL. We aimed to further substantiate the safety of continuing aspirin during PCNL surgery and to determine whether aspirin status affects postoperative outcomes following PCNL.

METHODS

We retrospectively queried our endourology database for patients who underwent PCNL from October 2017 to December 2022 at our high-volume tertiary referral center. The three groups were based on aspirin status at the time of PCNL: no aspirin (NA), discontinued aspirin (DA), and continued aspirin (CA). Data collected included demographics, preoperative characteristics, operative parameters, pre and postoperative lab values, transfusions, and complications.

RESULTS

A total 648 patients were divided into these study groups: 525 NA patients (81.0%), 55 DA (8.5%), and 68 CA (10.5%). The DA and CA groups were of similar comorbidities, and both were more comorbid at baseline than NA. Postoperative change in lab values and complications did not differ significantly. Rates of postoperative blood transfusion were higher in the CA and DA groups compared to NA and approached statistical significance. There were no significant differences in any postoperative outcomes between the DA and CA groups alone.

CONCLUSIONS

In patients on chronic aspirin therapy, continuing aspirin appears equally safe to discontinuing aspirin prior to PCNL. Most patients should not forego the benefits of continuous aspirin for the theoretical risk of bleeding. Patients on prolonged aspirin therapy may be more likely than those who are not on chronic aspirin therapy to require blood transfusions. However, regardless of whether aspirin use is stopped, this may be caused by patient comorbidities rather than higher rates of blood loss.

Understanding the link between kidney stones and cancers of the upper urinary tract and bladder

Kidney stones are one of the most common renal pathologies. While emerging evidence has implicated a potential association between kidney stones and upper urinary tract cancers (including renal cancer), there is limited understanding as to the common underlying biological pathways functionally linking the etiology of kidney stone formation and the incidence, development, and progression of urinary tract cancers. From a clinical perspective, kidney stone disease can be a barrier to oncologic care due to renal obstruction. From the epidemiological perspective, risk factors associated with both conditions include smoking, alcohol consumption, diet, and gender. Herein, we review the association between renal calculi and malignancy of the upper urinary tract and discuss the current understanding of (a) potential shared mechanisms, and (b) the impact this has on shared therapeutic management of both conditions.

Is metformin use associated with changes in urinary parameters in stone formers?

INTRODUCTION

Diabetes mellitus (DM) is associated with an increased risk of nephrolithiasis and is often treated with metformin. The relationship between metformin and nephrolithiasis formation remains unclear as studies have demonstrated conflicting results.

METHODS

We conducted a cross-sectional analysis of stone-forming patients at our stone clinic prior to the initiation of stone-directed medical management. Patients were grouped based on diabetic status and diabetic medication regimen. Outcomes evaluated were 24-hour urinary parameters and specimen stone type using univariate Kruskal-Wallis and Chi-squared analyses. Multivariate analyses controlling for metabolic syndrome components and HbA1c were performed.

RESULTS

Data were available for 505 patients, of whom 147 were diabetic and 358 were not. On multivariate analyses controlling for HbA1c and other comorbidities, diabetic patients on metformin still had worse urinary parameters, including urine pH, than non-diabetic patients (pH = -0.33, -0.37, p<0.05). Patients with DM on metformin did not exhibit significant differences in 24-hour urine findings compared to patients with DM not on metformin (p>0.05 for all urinary parameters).

CONCLUSIONS

Stone-forming patients with DM on metformin were associated with urinary abnormalities similar to those not on metformin. Cohort studies comparing urinary parameters of patients prospectively started on metformin are necessary to further elucidate metformin's role, if any, in combatting nephrolithiasis.

Prevention and Management of Infectious Complications of Retrograde Intrarenal Surgery

Kidney stone disease (KSD) is a commonly encountered ailment in urologic practice. Urinary tract infection (UTI) is commonly associated with KSD, both as an etiology (e.g., struvite and carbonate apatite stones), and as a complication (i.e., obstructive pyelonephritis and post-operative UTI). Indeed, a significant portion of the economic burden of KSD is skewed toward stones associated with infection. UTI is the most common post-operative complication related to stone intervention with progression to urosepsis as a rare but serious consequence. Risk for infection is influenced by a variety of factors including co-morbid conditions, anatomic abnormalities, prior surgical procedures, and local anti-microbial susceptibility. Understanding these risks and the proper steps to mitigate them is an essential component in reducing post-operative morbidity and mortality. Retrograde intrarenal surgery is routinely used for the treatment of KSD. The objective of this review article is to examine the current literature and guidelines for the prevention and management of stone-related infectious complications associated with retrograde intrarenal surgery. Special attention will be given to the incidence, etiology, and antibiotic prophylaxis choice in the management of stone-related infections. Intraoperative risk mitigation techniques will be discussed in conjunction with the management of post-operative infections. Antibiotic stewardship and the potential benefits of reduced empiric antibiotic treatment will also be discussed.

The impact of metabolic syndrome components on urinary parameters and risk of stone formation

PURPOSE

To investigate the relationship between metabolic syndrome (MS) and urinary abnormalities in stone-forming patients. Additionally, to delineate whether severity of urinary derangements is impacted by the number of co-occurring MS components.

METHODS

Stone-forming patients who underwent initial metabolic workup prior to medical intervention at a comprehensive stone clinic were retrospectively reviewed and included in the study. Patients were given a six point (0-5) Metabolic Syndrome Severity Score (MSSS) based on the number of co-occurring MS components and split into six respective groups. Baseline clinical characteristics and metabolic profiles were compared between groups.

RESULTS

Four-hundred-ninety-five patients were included in the study. Median age and median BMI was 58 years and 27.26 kg/m², respectively. Several significant metabolic differences were noted, most notably a downward trend in median urinary pH (p < 0.001) and an upward trend in median urinary supersaturation uric acid (p < 0.001) across groups as MSSS increased. Multivariate analysis demonstrated an independent association between higher MSSS and increasing number of urinary abnormalities. A second multivariate analysis revealed that all MS components except hyperlipidemia were independently associated with low urinary pH. Additionally, obesity was independently associated with the greatest number of urinary abnormalities and had the strongest association with hyperuricosuria.

CONCLUSIONS

Prior research has attributed the strong association of nephrolithiasis and MS to high prevalence of UA nephrolithiasis and low urinary pH. Our findings indicate that all MS components with the exception of hyperlipidemia were independently associated with low urinary pH suggesting a mechanism independent from insulin resistance.

Cancer, Mortality, and Acute Kidney Injury among Hospitalized Patients with SARS-CoV-2 Infection

Background:

To evaluate Coronavirus Disease 2019-(COVID19) patients treated within our academic medical system to determine if history of malignancy, both in general and specifically in genitourinary oncology patients, is associated with adverse clinical outcomes, including acute kidney injury (AKI) and mortality.

Methods:

We conducted a retrospective cohort study among patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a multi-hospital, academic medical institution in New York City. Outcomes included mortality, intensive care unit (ICU) admission and AKI among hospitalized patients. We also evaluated risk of hospitalization among all patients with SARS-CoV-2 infection. Multilevel logistic regression models were used for analysis.

Results:

We identified 6,893 patients who met inclusion criteria, of which 4,018 were hospitalized. Among hospitalized patients 374 (9%) had a history of cancer, 281 (7%) experienced AKI, and 1,045 (26%) died. In adjusted analyses, patients with a history of cancer had 1.33 (95% CI = 1.05, 1.69) times the odds of death compared to those without cancer and this appeared to be driven by lung cancer (odds ratio (OR) = 2.44, 95% CI= 1.05, 4.39). Patients with a history of genitourinary cancer were not at higher risk of mortality compared to those without cancer (OR=0.99, 95% CI= 0.61, 1.62). History of cancer was not associated with ICU admission or AKI in overall and subgroup analyses.

Conclusions:

Patients with a history of cancer who are hospitalized with SARS-CoV-2 infection are not at greater risk for AKI, though they are at higher risk for mortality as compared to patients without a history of cancer. The increased risk in mortality appears driven by patients with pulmonary neoplasms. Patients with a history of genitourinary malignancies do not appear to be at higher risk for AKI or for mortality compared to the general population.

Management of a Massive Bladder Stone Burden in an Elderly Comorbid Woman via a Transurethral Approach

Here we present the case of a 78-year-old medically comorbid woman with an extremely large bladder stone burden treated by cystolithalopaxy performed using a Swiss LithoClast^® Trilogy Lithotripter (Boston Scientific, Marlborough, MA, USA) through a nephroscope traversing a transurethral Amplatz sheath.

Thulium fiber laser utilization in urological surgery: A narrative review

The thulium fiber laser (TFL) is a novel technology under active investigation as an conceivable alternative to the Holmium:yttrium-aluminum-garnet (Ho:YAG) laser, which is currently the gold standard for an array of urologic procedures. The purpose of this review is to discuss the existing literature on the functionality and effectiveness of TFL in urological practice. We conducted a search of the PubMed, Medline, Web of Science Core Collection, SCOPUS, Embase (OVID), and Cochrane Databases for all full articles and systematic reviews on the TFL. We found a total of 35 relevant pieces of literature. The early research findings pertaining to the TFL exhibit numerous potential advantages over the Ho:YAG laser. In vitro and ex vivo studies have highlighted the TFL's ability to utilize smaller laser fibers, obtain faster stone ablation rates, and achieve less retropulsion when tested against the Ho:YAG laser in lithotripsy. Currently, there is limited in vivo research that investigates the utilization of the TFL. The in vivo results that are available, however, look promising both for laser lithotripsy and soft tissue ablation. Indeed, the existing literature suggests that the TFL has great potential and may possess numerous technological advantages over the Ho:YAG laser, especially in laser lithotripsy. Although these early studies are promising, randomized control trials are needed to assess the full applicability of the TFL in urology.