Contemporary Trends in Percutaneous Nephrolithotomy in the United States: 1998-2011

Changing Trends in Surgical Management of Nephrolithiasis among Young Adults: A 15-Year Population-Based Study

Background: Increases in obesity and diabetes rates among all ages have led to a greater prevalence of nephrolithiasis worldwide. We aimed to explore the changing trends in surgical management of nephrolithiasis in young adults over a 15 year period. Methods: We reviewed medical records of military personnel for information on the diagnosis and care of nephrolithiasis before and during active service between 2007−2021, divided into three 5 year periods: 2007−2011, 2012−2016, and 2017−2021. Demographic, clinical, radiological, and surgical data were retrieved for the analysis of changing trends. Results: The records of 1,117,692 recruits yielded 7383 (0.66%) with stone-related surgeries, of whom 1885 were operated during military service. Their median age was 19.6 years (interquartile range [IQR] 16.8−21.2), 829 (70%) were males, and the cohort’s median body mass index was 23.6 (IQR 17.3−26.1). There was a dramatic decline in shock wave lithotripsy (SWL) prevalence (35.1%, 10.4%, and 4.4%, respectively) with a continually increasing prevalence of ureteroscopy (URS)/retrograde intrarenal surgery (RIRS) (62.7%, 88.5%, and 94.6%, p = 0.01). Percutaneous nephrolithotomy (PCNL) procedures have become nearly extinct over time (0.8% in 2017−2021). The number of median-sized stones treated by URS/RIRS increased (7.5 mm, 8.2 mm, and 9.7 mm, p = 0.044), but not those treated by SWL/PCNL. The median length of medical leave for URS/RIRS and PCNL decreased significantly (7 vs. 4 days, p = 0.05 and 10 vs. 6 days, p = 0.036, respectively), with no comparable change for SWL. There was a substantial decline in ancillary procedures in the URS/RIRS groups (9%, 6.8%, and 3.1%, p < 0.01), but not in the SWL/PCNL groups. Conclusions: Advancements in technology and surgical training are leading to the extinction of SWL and the adoption of URS/RIRS as the new standard of care for nephrolithiasis among young adults.

Kidney Stone Surgery: Assessing Public Interest and Evaluating Social Media Content

An increasing number of patients are utilizing the internet to answer their medical questions. Given the lack of verified stone treatment resources on the web, we sought to evaluate online interest in kidney stone surgical interventions and assess the quality of the most popular resources on social media. Google Trends was used to evaluate public interest in different kidney stone interventions between March 2016 - February 2021 and reported as search volume index (SVI). Next, the social-analysis tool BuzzSumo was used to identify stone surgery content online on the social media platforms YouTube, Instagram, Twitter, Reddit, and Twitter. To evaluate the quality of health information presented in the online resources the DISCERN instrument was employed by three individual raters. Ureteroscopy (URS), Percutaneous Nephrolithotomy (PCNL) and Extracorporeal shock wave lithotripsy (ESWL) were identified as the top search terms on Google Trends with mean SVI's of 47.75, 42.98, and 45.74 respectively (P = 0.012). On YouTube, URS, PCNL, and ESWL had 12,549, 116,222, and 20,717 views respectively. Nine articles and fifteen videos were chosen for analysis using the DISCERN tool with a mean score of 2.82 and 2.27 respectively among three independent evaluators. The result of our study suggests that online users are interested in URS but engaged more often with PCNL content on social media platforms. We found that the quality of online resource related to stone surgery highlights the need for involvement of urologists in the creation of engaging high-quality content and accurate information sharing in a social media driven society.

Novel Irrigation Protocol for Renal Pelvis Sterilization During Percutaneous Nephrolithotomy: A Pilot Study

While percutaneous nephrolithotomy (PCNL) remains the treatment modality of choice for kidney stones larger than 2 cm, infectious complications are most common, ranging from 5% to 32%. We present here a novel technique for potentially improving collecting system sterility during PCNL and initial postoperative outcomes. Retrospective chart analysis data of our irrigation protocol were collected from our first 56 patients between February and July 2019. Traditional prone PCNL was performed in a standard manner using fluoroscopic guidance. Using a ureteral catheter that was placed cystoscopically, a renal pelvis urine culture was taken and subsequently 10 mL of betadine solution was instilled into the collecting system. Gentamicin in normal saline (80 mg/3 L) was utilized as the irrigant fluid for the first 6 L of irrigation. From this cohort, 57% patients were women and mean age was 60 ± 14 years. About 23% of patients were diabetic and 55% were hypertensive. Seventy percent of patients had stone burden >2 cm and no patients had stone burden <1 cm. Fifteen patients had positive urine cultures treated preoperatively, while four patients had contaminated cultures. All patients were treated with our antibiotic irrigation and betadine protocol regardless of preoperative cultures or antibiotics. Mean baseline creatinine level was 0.95 ± 0.41, with a mean change of 0.18 at postoperative day 1. Of the 15 (26%) of 56 patients with a systemic inflammatory response syndrome response (two of following four criteria: white blood cells <4 or >12; heart rate >90; hypothermia <96.8°F or hyperthermia >100.4°F; and respiratory rate >20), only six patients (11%) were febrile and two patients had positive blood cultures (3%). There were no adverse reactions to the betadine or antibiotic irrigation. We present here our initial experience of a new technique for renal pelvis sterilization and its safety and feasibility using intrarenal instillation of betadine and antibiotic irrigation. No Clinical Trial Registration number applicable.

Ureteroscopic Doppler Ultrasonography: Mapping Renal Blood Flow from Within the Collecting System

Introduction: Herein we provide the first report regarding in vivo porcine renal forniceal, papillary, and infundibular blood flow at the urothelial level using a novel ureteroscopic Doppler transducer. Materials and Methods: Nephroureteroscopy was performed on 11 female Yorkshire pigs to map the forniceal, papillary, and infundibular blood flow. A Doppler transducer was mounted to a 3F 120 cm catheter; the probe was passed through the working channel of a flexible ureteroscope. Blood flow was categorized from 0 (no flow) to 3 (highest flow) based on auditory intensity. At each site, a holmium laser probe was activated until it penetrated ∼1 cm into each of the examined areas; bleeding times were recorded. Results: The frequency of the Doppler transducer signal was proportional to the blood velocity within the vessel with expected increased bleeding times confirmed after puncture with a holmium laser. Analysis demonstrated that the 6 o'clock position of the fornix had significantly greater blood flow than any other forniceal location (p < 0.001). The center of each papilla had the least blood flow (p < 0.001). Blood flow was significantly higher at the infundibular level compared with the caliceal fornices at all locations (anterior, posterior, upper pole, midkidney, and lower pole) (p < 0.001). Conclusions: In a porcine model, a miniaturized Doppler ultrasound probe used during ureteroscopy demonstrated that the renal papilla had the least amount of blood flow whereas the infundibula had the highest blood flow. These data may serve to inform site selection during percutaneous nephrostomy placement.

Postoperative Emergency Department Visits After Urinary Stone Surgery: Variation Based on Surgical Modality

Introduction: Urinary stone disease is responsible for more than 1 million emergency department (ED) visits annually. There is increasing regulatory and cost pressure to reduce unplanned episodes of care, particularly after elective surgery. However, the frequency of ED visits in the early postoperative period after different modalities of stone surgery is not well characterized. We aimed at describing rates of postoperative ED visits after percutaneous nephrolithotomy (PCNL), ureteroscopy (URS), and extracorporeal shockwave lithotripsy (SWL). Methods: The Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project (HCUP) state databases for Florida (2010-2012), Iowa (2010-2012), California (2010-2011), and New York (2006-2012) were used to identify patients undergoing PCNL, URS, or SWL. The HCUP State Emergency Department Database was used to identify postoperative ED visits in the first 30 days after surgery. Rates of postoperative ED visits were compared across surgery types with chi-square and multivariate logistic regression. Results: A total of 321,899 patients undergoing stone surgery during the study period were identified, including 151,006 (46.9%) URS, 128,040 (39.8%) SWL, and 42,853 (13.3%) PCNL. PCNL had the highest rate of 30-day postop ED visits (13.2%), followed by URS (10.6%) and SWL (7.5%; p < 0.0001). On multivariate logistic regression adjusting for baseline clinical and sociodemographic characteristics, both PCNL (odds ratio [OR] 1.62, 95% confidence interval [CI] 1.56-1.69) and URS (OR 1.33, 95% CI 1.30-1.37) were independently associated with increased risk of postop ED visit when compared with SWL. Conclusion: Among kidney stone surgeries, PCNL has the highest rate of 30-day postoperative ED visits, whereas SWL has the lowest. Postoperative ED visits are an important outcome for both patients and surgeons, and observed differences across surgical modalities should be incorporated into the preoperative shared decision-making process.

Percutaneous Nephrolithotomy in Children: Analysis of Nationwide Hospitalizations and Short-Term Outcomes for the United States, 2001-2014

OBJECTIVE

To describe population-wide utilization rates and outcomes of percutaneous nephrolithotomy (PCNL) in the management of pediatric upper urinary tract calculi (UUTC).

PATIENTS AND METHODS

Patients <18 years with a diagnosis of UUTC, who underwent PCNL between 2001 and 2014 were identified from the National Inpatient Sample database. Annual PCNL rates, based on the at-risk population for each year, were estimated, and change in utilization rate was analyzed using negative binomial regression. Perioperative outcomes, hospital length of stay (LOS), and costs were determined; continuous and categorical variables were analyzed using nonparametric tests and Chi-squared tests, respectively. Trends tests and multivariable analyses (MVAs) were also performed where appropriate.

RESULTS

An estimated 3206 pediatric PCNL procedures were performed. Mean annual PCNL rate increased significantly relative to 2001 (incidence rate ratio = 1.40; 95% confidence interval 1.15-1.71, p = 0.001). Proportion of PCNL as a fraction of all inpatient surgical procedures for UUTC also significantly increased over time, from 15.7% in 2001 to 26.4% in 2014 (p < 0.0001). Complications overall occurred in 20.7% of cases, with a significantly rising rate over time period (p < 0.0001). Complication rates were similar across hospital types and geographic regions. Median hospitalization cost was significantly higher for the West than for each of the other regions (p < 0.05 in each case). Median LOS was also highest for the West (4 days vs 3 days for each of the other regions). In MVA, significant predictors of both increased LOS and costs included black race, comorbidities of hypertension, diabetes, coagulopathy and neurologic disease, hospitalization in the South, and presence of complications. Race, gender, comorbidities, and treatment year were among the predictors of complications.

CONCLUSIONS

PCNL utilization in the management of pediatric UUTC has significantly increased since 2001, with an associated increase in complication rates, although major complications were uncommon. Regional variations in costs and LOS were evident.

The evolution of percutaneous nephrolithotomy: Analysis of a single institution experience over 25 years

INTRODUCTION

Over time, the incidence of nephrolithiasis has risen significantly, and patient populations have become increasingly complex. Our study aimed to determine the impact of changes in patient demographics on percutaneous nephrolithotomy (PCNL) outcomes.

METHODS

A retrospective analysis of a prospectively collected database was carried out from 1990-2015. Patient demographics, comorbidities, stone and procedure characteristics were analyzed. Multivariate logistic regression was used to evaluate differences in operative duration, complications, stone-free rate, and length of stay.

RESULTS

A total of 2486 patients with a mean age of 54±15 years, body mass index (BMI) of 31±8, and stone surface area of 895±602 mm² were analyzed; 47% of patients had comorbidities, including hypertension (22%), diabetes mellitus (14%), and cardiac disease (13%). Complication rate was 19%, including a 2% rate of major complications (Clavien grade III-V). There was a statistically significant increase in patient age, BMI, and comorbidities over time, which was correlated with an increased complication rate (odds ratio [OR] 1.15; p=0.010). The overall transfusion rate was 1.0% and remained stable (p=0.131). With time, both OR duration (mean Δ 16 minutes; p<0.001) and hospital length of stay (mean Δ 2.4 days; p<0.001) decreased significantly. Stone-free rate of 1873 patients with available three-month followup was 87% and decreased significantly over time (OR 1.09; p<0.001), but was correlated with an increased use of computed tomography (CT) scans for followup imaging.

CONCLUSIONS

Despite an increasingly complex patient population, PCNL remains a safe and effective procedure with a high stone-free rate and low risk of complications.

Contemporary Trends in Percutaneous Nephrolithomy Across New York State: A Review of the Statewide Planning and Research Cooperative System

Introduction and Objectives: Percutaneous nephrolithotomy (PCNL) is a complex multistep surgery that has shown a steady increase in use for the past decade in the United States. We sought to evaluate the trends and factors associated with PCNL usage across New York State (NYS). Our goal was to characterize patient demographics and socioeconomic factors across high-, medium-, and low-volume institutions. Materials and Methods: We searched the NYS, Statewide Planning and Research Cooperative System (SPARCS) database from 2006 to 2014 using ICD-9 Procedure Codes 55.04 (percutaneous nephrostomy with fragmentation) for all hospital discharges. Patient demographics including age, gender, race, insurance status, and length of hospital stay were obtained. We characterized each hospital as a low-, medium-, or high-volume center by year. Patient and hospital demographics were compared and reported using chi-square analysis and Student's t-test for categorical and continuous variables, respectively, with statistical significance as a p-value of <0.05. Results: We identified a total of 4576 procedures performed from 2006 to 2014 at a total of 77 hospitals in NYS (Table 1). Total PCNL volume performed across all NYS hospitals increased in the past decade, with the greatest number of procedures performed in 2012 to 2013. Low-volume institutions were more likely to provide care to minority populations (21.4% vs 17.3%, p < 0.001) and those with Medicaid (25.5% vs 21.5%, p < 0.001). High-volume institutions provided care to patients with private insurance (42.1% vs 34.0%, p < 0.001) and had a shorter length of stay (3.3 days vs 4.1 days, p < 0.001). Conclusion: Our data provide insight into the patient demographics of those treated at high-, medium-, and low-volume hospitals for PCNL across NYS. Significant differences in race, insurance status, and length of stay were noted between low- and high-volume institutions, indicating that racial and socioeconomic factors play a role in access to care at high-volume centers.

Differences in the percutaneous nephrolithotomy practice patterns among Latin American urologists with and without endourology training

PURPOSE

Although the worldwide percutaneous nephrolithotomy (PCNL) practice patterns determined via a survey sent to members of the Endourological Society have been published, differences in PCNL practice patterns among Latin American urologists based on endourological or lithiasis training have not been published. To determine the PCNL practice patterns among Latin American urologists with and without training in endourology.

MATERIALS AND METHODS

The SurveyMonkey® web platform was used to develop a 27- item survey on PCNL for the treatment of renal stones, and the survey was sent via e-mail and other electronic media to 2000 urologists from 15 Latin American countries. Endourology-trained (group 1) and nontrained urologists (group 2) were analyzed. The group results were compared using the chi-squared and Fisher's exact tests. SPSS version 20 for Windows was used for all analyses.

RESULTS

A total of 331 urologists responded to the survey (rate of 16.55%): 221 (66.7%) in group 1 and 110 (33.2%) in group 2). In groups 1 and 2, 91.9% and 63.2% performed PCNL, respectively; 85.1% and 58.5% used preoperative tomography, respectively; 12.7% and 4.7% used preoperative nephrolitometry nomograms, respectively; 45.2% and 32.1% used endoscopic combined intrarenal surgery, respectively; 68.3% and 38.7% used multiple percutaneous tract realization, respectively; and 19.9% and 5.7% used minimally invasive PCNL, respectively (all p=0.0005).

CONCLUSIONS

Statistically significant differences were observed in PCNL practice patterns of Latin American urologists with and without training in endourology. Specific training in endourology significantly influence the practice patterns of Latin American urologists.

Contemporary Trends in Utilization and Perioperative Outcomes of Percutaneous Nephrolithotomy in the United States from 2003 to 2014

PURPOSE

To investigate the contemporary trends and perioperative outcomes of percutaneous nephrolithotomy (PCNL) by using a population-based cohort.

MATERIALS AND METHODS

Using the Premier Healthcare Database, we identified 225,321 patients in whom kidney/ureteral calculi were diagnosed and who underwent PCNL at 447 different hospitals across the United States from 2003 to 2014. Outcomes included 90-day postoperative complications (as classified by the Clavien-Dindo system), prolonged hospital length of stay, operating room time, blood transfusions, and direct hospital costs. Temporal trends were quantified by estimated annual percentage change (EAPC) by using least-squares linear regression analysis. Multivariable logistic regression was performed to identify predictors of outcomes.

RESULTS

PCNL utilization rates initially increased from 6.7% (2003) to 8.9% (2008) (EAPC: +5.60%, p = 0.02), before plateauing at 9.0% (2008-2011), and finally declining to 7.2% in 2014 (EAPC: -4.37%, p = 0.02). Overall (Clavien ≥1) and major complication (Clavien ≥3) rates rose significantly (EAPC: +12.2% and +16.4%, respectively, both p < 0.001). Overall/major complication and blood transfusion rates were 23.1%/4.8% and 3.3%, respectively. Median operating room time and 90-day costs were 221 minutes (interquartile range [IQR] 4) and $12,734 (IQR $9419), respectively. Significant predictors of overall complications include higher Charlson comorbidity index (CCI) (CCI ≥2: odds ratio [OR] 2.08, p < 0.001) and more recent year of surgery (2007-2010: OR 3.20, 2011-2014: OR 4.39, both p < 0.001). Higher surgeon volume was significantly associated with decreased overall (OR 0.992, p < 0.001) and major (OR 0.991, p = 0.01) complications.

CONCLUSIONS

Our contemporary analysis shows a decrease in the utilization of PCNL in recent years, along with an increase in complication rates. Numerous patient, hospital, and surgical characteristics affect complication rates.