Urinary Stone Surgery Research Articles

Editorial Comment on "Variation in Urology Care after Urinary Stone Surgery among Veterans at High-risk for Recurrence

Editorial Comment on "Variation in Urology Care after Urinary Stone Surgery among Veterans at High-risk for Recurrence

The Stockholm Spinal Cord Uro Study: Changing patterns of urological surgery in a regional prevalence group through 50 years - Outcomes and lessons learned.

To examine the number and types of urological surgical procedures carried out in a regional prevalence population of patients with traumatic spinal cord injury (SCI) during five decades, evaluate objective and patient-reported outcomes and to consider lessons learned for further improvement of surgical treatment in this patient group. In a cross-sectional study of 412 patients with traumatic SCI, one-third had undergone urological surgery through a period of up to 50 years. Data on types of surgery, complications, follow-up and outcomes were collected in a retrospective review of patient files. S-creatinine, S-cystatin-C, renal ultrasound and a questionnaire regarding complications during the preceding year were assembled as part of a yearly follow-up. Descriptive statistics were calculated. Logistic regression was used to determine risk profiles for the incidence of urological surgery. A total of 137 patients had undergone 262 urological surgical interventions. The incidence was highest amongst persons with a cervical-thoracic neurological level of spinal cord lesion and during the first 2 years after SCI. Surgery for urinary stones constituted 29% of all procedures. One-fourth of the patients had undergone 47% of all procedures, notably urinary diversion and ensuing complications, implants and revisions, repeated stone interventions or bladder outlet procedures. After reconstructive surgery functional outcomes and patient-reported satisfaction were generally favourable, but long-term signs of renal complications were frequent. Urological surgery after SCI involves imperative as well as reconstructive procedures, some of which are challenging and call for centralisation to devoted teams. Prospective studies of reconstructive urology are warranted, including more extensive patient-reported outcomes.

Variation in Urology Care After Urinary Stone Surgery Among Veterans at High-risk for Recurrence

ObjectiveTo determine rates of urology follow-up and implementation of stone prevention measures after stone surgery and to assess variation in care delivery within a large, integrated healthcare system. Materials and MethodsWe used nationwide data from the United States Veterans Health Administration to identify patients who had stone surgery between 2016 and 2018 and who were at higher risk for recurrence. Our cohort included 13,444 Veterans across 90 facilities. We examined the proportion of patients who had a post-operative urology visit or who received a prevention measure (24-hour urine test, serum parathyroid hormone measurement, or prescription of a stone-related medication) within 6 months of stone surgery. We calculated the median odds ratio to quantify facility-level variation in urology care after stone surgery, adjusting for patient- and facility-level characteristics. ResultsWithin 6 months of stone surgery, 94.2% Veterans had a urology visit, yet only 8.8% completed 24-hour urine testing, 8.4% had a parathyroid hormone measurement, and 31.0% were prescribed a stone-related medication. Implementation of prevention measures varied widely across facilities with the median odds ratio ranging between 1.18 for medication prescriptions and 1.77 for 24-hour urine testing. ConclusionsWhile most patients have a urology visit after stone surgery, stone prevention measures were implemented infrequently and inconsistently for patients at higher risk for recurrence, indicating an opportunity for quality improvement.

The value of 3D printing model combined PCNL in kidney stones: a systematic review and meta-analysis.

With the continuous advancement of medical imaging, 3D printing technology is emerging. This technology allows for the representation of complex objects in a model form. This research aims to delve into the irreplaceable value of percutaneous nephrolithotomy (PCNL) in conjunction with 3D printed models in urinary stone surgery. This forward-looking approach provides doctors with a new perspective, enabling them to plan and execute surgeries with greater precision, ultimately delivering a safer and more efficient treatment experience for patients. We evaluated the literature on PCNL for the kidney stones with the introduction of 3D printing models and conducted a meta-analysis. The assessed parameters included stone clearance rate, operation time, hospital stay, blood loss, puncture accuracy, and the rate of complications. We systematically searched the EMBASE, PubMed, Cochrane Library, SCIE, and Chinese Biomedical Literature Search databases for articles related to PCNL (Percutaneous Nephrolithotomy) with 3D printing models from January 2000 to January 2023. Data were managed and screened using Excel . Meta-analysis was performed for operation time, stone clearance rate, blood loss, puncture accuracy, length of hospital stay, and complications in PCNL combined with 3D printing model for kidney stone treatment. The quality of included articles was assessed using the risk of bias tool by the Cochrane Collaboration. Sensitivity analysis was conducted to assess the reliability of the results. Data were recorded using StataSE 17 software, and publication bias was examined using Egger's linear regression test. We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to conduct a systematic search and screening of literature relevant to the use of 3D printed models in the treatment of kidney stones. We conducted an extensive literature search across several major academic databases, including EMBASE, PubMed, Cochrane Library, SCIE, and Chinese Biomedical Literature Search databases, to ensure comprehensive coverage of relevant studies. Following the PRISMA process of screening and analysis, we ultimately included 10 randomized controlled trials with a combined sample of 608 for systematic review. Across these studies, we identified the introduction of 3D printing models prior to surgery for kidney stones resulted in significant advantages for the experimental group compared to the control group in terms of operation time, stone clearance rates, puncture accuracy, hospital stay, blood loss, and the incidence of complications, providing valuable insights for further research and clinical practice.

The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study

PurposeResidual fragments not removed with urinary stone surgery may become symptomatic. In this context, this study was carried out to investigate the effect of performing retrograde intrarenal surgery, which is conventionally performed in the lithotomy position, in the modified lithotomy position (Trend-side) on stone-free rates following the surgery.MethodsThis prospective study consisted of 100 patients with a single kidney stone smaller than 2 cm between 2021 and 2023. These patients were randomized into two groups of 50 patients each to be operated on in the conventional lithotomy and Trend-side positions. Variables were compared using independent t test for continuous variables and chi-square test for categorical variables.ResultsThere was no significant difference between the lithotomy and Trend-side position groups in terms of preoperative size, density, location of the stone, and hydronephrosis degree. Stone-free rate was 72% (n = 36) in the lithotomy group and 92% (n = 46) in the Trend-side group. Hence, there was a significant difference between the groups in the stone-free rate in favor of the Trend-side group (p = 0.009). Fragmentation time was statistically significantly shorter in the Trend-side group than in the lithotomy group (34 ± 17 min vs. 43 ± 14 min; p = 0.006). There was no significant difference between the groups in postoperative complication rates.ConclusionPerforming retrograde intrarenal surgery in the Trend-side position shortened the duration of fragmentation compared to the lithotomy position and was associated with higher stone-free rates. In conclusion, the Trend-side position can be safely preferred in patients undergoing retrograde intrarenal surgery due to kidney stones.

Establishment and application of a nomogram diagram for predicting calcium oxalate stones in patients with urinary tract stones

This retrospective study aims to examine the correlation between calcium oxalate (CaOx) stones and common clinical tests, as well as urine ionic composition. Additionally, we aim to develop and implement a personalized model to assess the accuracy and feasibility of using charts to predict calcium oxalate stones in patients with urinary tract stones. A retrospective analysis was conducted on data from 960 patients who underwent surgery for urinary stones at the First Affiliated Hospital of Soochow University from January 1, 2010, to December 31, 2022. Among these patients, 447 were selected for further analysis based on screening criteria. Multivariate logistic regression analysis was then performed to identify the best predictive features for calcium oxalate stones from the clinical data of the selected patients. A prediction model was developed using these features and presented in the form of a nomogram graph. The performance of the prediction model was assessed using the C-index, calibration curve, and decision curve, which evaluated its discriminative power, calibration, and clinical utility, respectively. The nomogram diagram prediction model developed in this study is effective in predicting calcium oxalate stones which is helpful in screening and early identification of high-risk patients with calcium oxalate urinary tract stones, and may be a guide for urologists in making clinical treatment decisions.

Comparing outcomes of single-use vs reusable ureteroscopes: a systematic review and meta analysis.

Flexible ureterolithotripsy is a frequent urological procedure, usually used to remove stones from the kidney and upper ureter. Reusable uretero-scopes were the standard tool for that procedure, but recent concerns related to sterility and maintenance and repair costs created the opportunity to develop new technologies. In 2016, the first single-use digital flexible ureteroscope was introduced. Since then, other single-use ureteroscopes were developed, and studies compared them with the reusable ureteroscopes with conflicting results. The purpose of this study is to describe the literature that compares the performance of single-use and reusable flexible ureteroscopes in retrograde intrarenal surgery for urinary stones. A Systematic Review was performed in October 2022 in accordance with the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA). A search in MEDLINE, EMBASE, Web of Science, Google Scholar and LILACS retrieved 10,039 articles. After screening, 12 articles were selected for the Meta-Analysis. No differences were found in stone-free rate (OR 1.31, CI 95% [0.88, 1.97]), operative time (MD 0.12, CI 95% [-5.52, 5.76]), incidence of post-operative fever (OR 0.64, CI 95% [0.22, 1.89]), or incidence of post-operative urinary tract infection (OR 0.63 CI 95% [0.30, 1.32]). No differences were observed in the studied variables. Hence, the device choice should rely on the availability, cost analysis and surgeons' preference.

In Vıvo Evaluatıon Of The Chemıcal Composıtıon Of Urınary Stones Usıng Non-Contrast Helıcal Computerized Tomography

ABSTRACT: 
 Aim:
 To determine the density and chemical structure of renal stones by using in vivo low dose helical computerized tomography.
 Methods:
 79 patients with renal or uretheral stones were included in our study who were going to have extracorporeal shock wave lithotripsy (ESWL) or planned to go through urinary stone surgery due to renal stones. All stone densities were measured in Hounsfield Unit by low dose abdominal non-contrast helical computed tomography examination. Marconi MX 8000 CT system with 4 detectors was used for the CT examination. X-Ray diffractometry was used in the analyses of all stones.
 Results:
 The stone type was found to be one type, and mixed stone in 27 patients. The largest group among the mixed stones included whevellite-weddellite stone with 17 patients. Uric acid stones had the smallest, whevellite stones had the highest density. The difference between the density values of uric acid and cystine stones and the other stone types were statistically significant.
 Conclusion:
 Non-contrast helical computed tomography used in the diagnosis can also be used in the in vivo determination of the stone composition. It can be very helpful to define stone compositions by imaging studies to provide suitable therapeutic alternatives.

Association of stone surgery with patient-reported complications after spinal cord injury.

To determine if a history of urinary stone surgery in individuals with spinal cord injury (SCI) is associated with an increased incidence of SCI-related complications and lower quality of life (QOL). The Neurogenic Bladder Research Group (NBRG) registry is a multicenter, prospective, observational study which measures QOL after acquired SCI. Over 1.5 years, 1479 participants were enrolled and grouped according to history of stone surgery. We evaluated SCI-related complications, QOL, and associations between patient factors and prior stone surgery using multivariable regression. Participants were a median of 11 years post-SCI and 189 (12.8%) reported prior bladder or kidney stone surgery; 95.8% of these occurred after the SCI. Median time between SCI and first stone was 5.6 years (IQR: 1.8-12.8). Hospitalizations were higher for those with prior stone surgery, with common reasons including UTIs, blood clots, pressure ulcers, and pneumonia (p < 0.001). During the year of observation, the incidence of stone surgery was 17% in those with a prior history of stone surgery and 2% per year in those without prior stone surgery (p < 0.001). Controlling for covariates, bladder management strategy, age, BMI, and years since SCI were associated with history of stone surgery. People with SCI and a history of surgical stone disease are at high risk for episodes of recurrent stones and increased hospitalizations, particularly those with kidney stones and indwelling catheter use. Identification of high-risk patients may guide tailored surveillance for complications and stone prevention strategies.

Osteogenezis imperfekta tanılı pediatrik hastada ultra-mini perkütan nefrolitotomi

Osteogenesis imperfecta (OI) is a rare, inherited disease group with genetic and clinical diversity. There is a defect in the type 1 collagen structure. Increasing bone fragility, osteopenia, and skeletal deformities can be seen. Surgical applications in patients with OI may cause complications such as spinous process injury in vertebrates or bone fracture. Therefore, in the management of pediatric urolithiasis, the decision of surgery should be carefully considered, and safe techniques that shorten the procedure time should be preferred. Percutaneous nephrolithotomy (PCNL) operation is the first choice for large kidney stones in adult patients. Along with the technological advances, more minimally invasive approaches such as mini-PCNL, ultra-mini-PCNL, and micro-PCNL have been developed, and these methods are safely used in pediatric patients due to their low morbidity. Because of its potential risks, urinary stone surgery in OI patients has rarely been reported in the literature. This study presents a 4-year-4-month-old girl with OI and kidney stone, whom we performed ultra-mini-PCNL. Keywords: endourology, urolithiasis, pediatric urology, ultra mini pcnl

Open Surgery for Urinary Stones in a Resource Poor Setting: A Look at Dalhatu Araf Specialist Hospital, Lafia, Nigeria

Urinary stone disease has afflicted humankind since antiquity[1]. It remains a common urological condition worldwide, including in our environment[2]. Although open surgery was previously the main option for stone removal, advances in technology mean that treatment is now largely through minimally invasive surgery, as recommended by a number of urological guidelines[3,4]. Unfortunately, at our centre, we still treat urinary stones solely through open surgery, mostly because we lack endoscopic equipment. In addition, most of our patients, even if referred to facilities where endoscopic management is possible, cannot afford the cost of treatment.

Antibacterial effect of fosfomycin tromethamine on the bacteria inside urinary infection stones.

This study sought to evaluate the antibacterial effect of fosfomycin tromethamine (FT) on the bacteria inside urinary infection stones. The internal structures of urinary stones were observed via scanning electron microscopy to verify the presence of internal bacteria. We randomly assigned equal numbers of patients with kidney stones who met the inclusion criteria into two groups in a prospective study and treated them with different perioperative antibiotics. One group (experimental group) was treated with FT, and the other (control group) was treated with cefuroxime sodium. All stone specimens were collected via percutaneous nephrolithotomy (PCNL). The primary infection stones were screened via a stone component analysis, 30 cases in the experimental group and 31 cases in the control group. High-performance liquid chromatography (HPLC)-mass spectrometry was used to measure the drug concentration inside the stones, the bacterial count was calculated via stone culture, and the clinical infection index were monitored for between-group comparisons. Compared with the control group, the experimental group had a higher internal drug concentration, a higher drug sensitivity against various pathogenic bacteria, a lower bacterial colony count in the stone culture, and a lower incidence of postoperative clinical infection. FT is more effective than cefuroxime, which is commonly used during the perioperative period of urinary stones, and exerts a high antibacterial effect on these internal bacteria, and effectively reduces the probability of infection and sepsis after urinary stone surgery. FT can be used as an antibiotic during the perioperative period of urinary stones.

Care Setting as a Modifiable Predictor of Perioperative Cost and Outcomes following Elective Urinary Stone Surgery.

We sought to identify predictors of index surgical care setting and to determine if care setting influences risk adjusted perioperative costs and/or 30-day revisits following elective surgery for urinary stones. Using 2014 HCUP (Healthcare Cost and Utilization Project) all payer claims data from New York and Florida, we retrospectively identified 29,433 patients undergoing index ureteroscopy or shock wave lithotripsy. We used inverse probability of treatment weighting adjusted multivariable logistic and gamma regression to assess the association between index surgical care setting and 30-day revisits and total costs, respectively. Most urinary stone procedures (70.8%) were performed in the ambulatory setting. Underinsurance was associated with lower odds of undergoing surgery in the ambulatory setting (Medicaid vs private: OR 0.44, 95% CI 0.37-0.53; p <0.001; self-pay vs private: OR 0.21, 95% CI 0.17-0.26; p <0.001). Adjusted mean index surgical and 30-day acute care costs were significantly lower among ambulatory vs inpatient/emergency department cases ($4,746.10 vs $10,669.26 and $5,434.42 vs $11,729.39, both p <0.001), respectively. Ambulatory surgery was independently associated with lower odds of experiencing a 30-day revisit (OR 0.82, 95% CI 0.72-0.94; p=0.005). Urinary stone cases managed surgically in an ambulatory setting had lower risk adjusted costs and odds of a 30-day revisit compared to those managed in an inpatient setting. Our findings support use of ambulatory rather than inpatient based elective surgery for uncomplicated urinary stones. We invite clinicians and policymakers alike to reconsider clinical and nonclinical factors that influence pathways of care.

Payer Type, Race/Ethnicity, and the Timing of Surgical Management of Urinary Stone Disease.

Surgery for upper tract urinary stone disease is often reserved for symptomatic patients and those whose stone does not spontaneously pass after a trial of passage. Our objective was to determine whether payer type or race/ethnicity is associated with the timeliness of kidney stone surgery. A population-based cohort study was conducted using the California Office of Statewide Health Planning and Development dataset from 2010 to 2012. We identified patients who were discharged from an emergency department (ED) with a stone diagnosis and who subsequently underwent a stone surgery. Primary outcome was time from ED discharge to urinary stone surgery in days. Secondary outcomes included potential harms resulting from delayed stone surgery. Over the study period, 15,193 patients met the inclusion criteria. Median time from ED discharge to stone surgery was 28 days. On multivariable analysis patients with Medicaid, Medicare, and self-pay coverage experienced adjusted mean increases of 46%, 42%, and 60% in time to surgery, respectively, when compared with those with private insurance. In addition, patients of Black and Hispanic race/ethnicity, respectively, experienced adjusted mean increases of 36% and 20% in time to surgery relative to their White counterparts. Before a stone surgery, underinsured patients were more likely to revisit an ED three or more times, undergo two or more CT imaging studies, and receive upper urinary tract decompression. Underinsured and minority patients are more likely to experience a longer time to stone surgery after presenting to an ED and experience potential harm from this delay.

Urologic health condition of spinal cord-injured patients living in Turkey

To determine the urologic health condition of spinal cord-injured (SCI) patients living in Turkey, and to analyze the relationship between the prevalence of urologic health condition parameters and the patient's characteristics. Telephone call survey was conducted with a structured questionnaire among all members of Turkish Society of Spinal Cord Injured Patients. Data were obtained from 300 patients. Mean age was 42 years with a male/female ratio of 2.3, while the most common cause of injury was transport (35.3%). Although 70% were aware of potential kidney and bladder problems after injury >60% of the patients were not under regular urologic follow-up. Secondary health problems experienced as being most important was urination problems (50%). Of the patients 72.7% (83% in females vs 68% in males) had urinary incontinence (UI) during last 3 months, and 64.3% used clean intermittent catheterization (CIC) (68% in males vs. 56% in females), while 73%, 57% and 26% of incontinent patients used diaper/pad, medication and condom catheter, respectively, and the use of CIC decreased with time. Surgical procedures on urinary tract were performed in 22.6% of the patients; stone surgeries were the most frequent ones. This study demonstrated that the UI rate was high among SCI patients, and more common in females with fairly good proportion of patients using incontinence medication. Main bladder management method was CIC and more prevalent in males, although the use of CIC decreased with time. Urinary stone surgery was the leading surgical procedure.

Medicare Payments for Outpatient Urological Surgery by Location of Care

The cost implications associated with offloading outpatient surgery from hospitals to ambulatory surgery centers and the physician office remain poorly defined. Therefore, we determined whether payments for outpatient surgery vary by location of care. Using national Medicare claims from 1998 to 2006, we identified elderly patients who underwent 1 of 22 common outpatient urological procedures. For each procedure we measured all relevant payments (in United States dollars) made during the 30-day claims window that encompassed the procedure date. We then categorized payment types (hospital, physician and outpatient facility). Finally, we used multivariable regression to compare price standardized payments across hospitals, ambulatory surgery centers and the physician office. Average total payments for outpatient surgery episodes varied widely from $200 for urethral dilation in the physician office to $5,688 for hospital based shock wave lithotripsy. For all but 2 procedure groups, ambulatory surgery centers and physician offices were associated with lower overall episode payments than hospitals. For instance, average total payments for urodynamic procedures performed at ambulatory surgery centers were less than a third of those done at hospitals (p <0.001). Compared to hospitals, office based prostate biopsies were nearly 75% less costly (p <0.001). Outpatient facility payments were the biggest driver of these differences. These data support policies that encourage the provision of outpatient surgery in less resource intensive settings.

Is there still a need for open/laparoscopic surgery for urinary stones?

SUMMARY Over the past 30 years the treatment of renal calculous disease has changed dramatically. With the advent of extracorporeal lithotripsy and the advances in ureteroscopy, and percutaneous nephrolithotomy, the need for both open and laparoscopic treatments for renal stone disease has been virtually eliminated. In spite of these advances in technology and technique there still remains a small but crucial role for open and laparoscopic treatments for renal stones. The goal of this article is to identify specific clinical scenarios that would require an open/laparoscopic approach for the treatment of kidney stone disease.

Are Stone Protocol Computed Tomography Scans Mandatory for Children With Suspected Urinary Calculi?

To examine the clinical utility of noncontrast-enhanced computed tomography (NCCT) in pediatric patients with urolithiasis who progressed to surgery. Although NCCT is routine for the evaluation of adult patients with suspected urolithiasis, its routine use in the pediatric population is tempered by concern about radiation exposure. We conducted a retrospective chart review of all pediatric patients who had undergone surgery for urinary stones from 2003 to 2008 at our institution. The imaging modalities used, surgery type, stone composition, 24-hour urinalyses, and relevant predisposing conditions were characterized. A total of 42 pediatric patients (24 males and 18 females) were treated during the 6-year period. The average age was 11.3±5.3 years (range 2.7-25.4), and the most common treatment modalities were shock wave lithotripsy (28%) and ureteroscopy (22%). A discernible risk factor or cause of urolithiasis was absent in 21 patients (47%). A review of imaging studies found 38 with stones visible on ultrasonography and/or abdominal plain film. A total of 21 patients underwent NCCT, in addition to ultrasonography and/or abdominal plain film. Of these, only 5 patients required NCCT for the diagnosis or management of their stone. Nearly 90% of pediatric patients treated for symptomatic urolithiasis could have completed their evaluation and treatment without undergoing NCCT. For children who present with signs and symptoms suggesting urinary calculi, an initial evaluation and imaging with ultrasonography and abdominal plain film might suffice, avoiding the radiation of NCCT.

1546 PRACTICE PATTERNS FOR INPATIENT URINARY STONE SURGERY IN U.S.

INTRODUCTION AND OBJECTIVES: The increasing prevalence of urinary stone disease has been demonstrated in numerous studies. Understanding differences in urinary stone surgery practice patterns may optimize healthcare, since different surgical techniques have different outcomes. We sought to describe the U.S. inpatient surgical practice patterns for urinary stones and determine what factors predict particular urinary stone surgery. METHODS: We used the NIS (Nationwide Inpatient Sample) database from 1998–2007 to identify 380,531 patients who underwent one of three urinary stone surgeries: percutaneous nephrolithotomy (PNL) ICD-9 55.04, 55.03, 55.21; shock wave lithotripsy (SWL) ICD-9 98.51; ureteroscopy (URS) ICD-9 56.31. Descriptive statistics were used to illustrate surgical frequencies and their potential covariates: demographics, co-morbidities, academic/community hospital, rural/urban location, U.S. geographic region (Northeast, Midwest, South, West), patient income, payer mix, and year. Linear regression illustrated surgical trends over time. Using above covariates, we compared on multi-variate analysis the odds of undergoing SWL to PNL as well as SWL to URS, as these are commonly comparable modalities. RESULTS: URS was the most common procedure (58.9%) with SWL slightly less common (22.4%) and PNL least common (16.9%) among inpatients undergoing urinary stone surgery. Over time, there was a significant increase in the utilization of PNL (p 0.001), SWL remained stable (p 0.213) and ureteroscopy declined (p 0.001). On multivariate analysis SWL was statistically more likely performed than PNL in younger subjects, male subjects, community hospitals, or rural hospitals. On multivariate analysis SWL was statistically more likely performed than URS in older subjects, male subjects, rural hospitals, or if location was South or West. CONCLUSIONS: Trends in inpatient renal stone surgery continue to evolve during the time period of our study with increasing adoption of PNL and decreasing use of ureteroscopy. Age and gender as well as type of hospital and its rural location predict SWL use over PNL, despite the lower efficacy associated with SWL technology. Assuming equal stone size (data not available), further explanation is necessary to reconcile these differences. Similar findings were found in the SWL versus URS analysis, though SWL appeared to have regionalization. Further investigation is necessary to understand causes for the differences inpatient practice patterns and whether outpatient practice patterns share common findings.

Changing Practice Locations for Upper Urinary Tract Stone Disease

Complex surgical procedures are migrating out of hospitals and into ambulatory surgery centers. We evaluated the extent to which surgery for urolithiasis could be a candidate for such migration. Patients undergoing stone surgery in Florida (107,417) between 1998 and 2004 were included in the study. Poisson models were fit to assess temporal changes in the setting (inpatient, outpatient and ambulatory surgery center) and type (open, percutaneous, extracorporeal, ureteroscopy and stenting) of stone surgery. For inpatient procedures secular trends in comorbidity burden (0 or 1 diagnoses vs 2 or more) and procedure acuity (elective vs emergency) were also assessed. Admission requirements and mortality rates were measured according to the surgery setting. Of the 107,417 discharges from 1998 to 2004 surgery rates per 100,000 increased from 35.5 to 38.2 for inpatients (p <0.05), 84.2 to 104.7 for hospital outpatients (p <0.01) and 9.4 to 26.9 for ambulatory surgery centers (p <0.01). For hospitalized patients routine admissions decreased (41.8% to 29.5%, p <0.01) and procedure acuity increased (16.8% to 28.2%, p <0.01). No deaths occurred at ambulatory surgery centers and the rate of admission to acute care hospitals was 2.5/100,000 cases. Despite the safety and efficiency of ambulatory surgery centers hospital outpatient departments remain the preferred setting for urinary stone surgery. For patients requiring surgical intervention for urinary stone disease ambulatory surgery centers could be an underused resource.