Postoperative Recovery of Quality-of-Life Following Ureteroscopy for Nephrolithiasis: The Impact on Pain Intensity and Interference and the Ability to Participate in Social Roles.

OBJECTIVE: To prospectively capture patient-reported outcomes to assess the recovery profile of ureteroscopy (URS). MATERIALS AND METHODS: Adults undergoing URS for renal/ureteral stones were eligible for inclusion (11/2020-8/2022). Patients prospectively completed PROMIS - Pain Intensity, - Pain Interference, and - Ability to participate in social roles and activities in-person preoperatively (POD 0) and via email on POD 1, 7, 14, and 30. Scores are reported as T-scores (normalized to U.S. population, mean=50) with a change of 5 (0.5 SD) considered clinically significant. RESULTS: One hundred and seventy-eight participants enrolled at POD 0 (POD 1 =87, POD 7 =83, POD 14 =70, POD30 =67). There was a worsening of quality of life from day 0 to day 1 and day 0 to 7. All dimensions then improved with an increase in scores from day 0 to day 14 and day 0 to day 30. On multivariable analysis, the presence of a preoperative ureteral stent (OR 0.14) and use of semirigid URS (OR 0.33) were associated with a reduced odds for severe pain interference at day 1. The use of semirigid URS (OR 0.20) was associated with a reduced odds for severe worsening in the ability to participate in social roles at day 1. CONCLUSION: Ability to participate in social roles declines immediately postoperatively, while pain intensity and interference sharply increase. There is a gradual improvement until POD 30. Findings suggest preoperative stents may influence postoperative recovery. Results offer meaningful insight to assist in counseling and setting expectation for patients postoperatively.

Cystinuria Complicated by Anuria From Bilateral Obstructing Stones Requiring Bilateral Mini Percutaneous Nephrolithotomy in a 22-Month-Old.

Pediatric nephrolithiasis is increasing in incidence and presents differently compared to adults. We report a case of nephrolithiasis in a pediatric patient, presenting with complaints of emesis, anuria, hematuria, and abdominal distension, leading to a diagnosis of bilateral obstructing cystine stones requiring bilateral percutaneous nephrolithotomy. Pediatric patients with anuria should be evaluated for bilateral nephrolithiasis as an etiology. Calculous anuria requires prompt recognition of the pathologic process and relief of the obstruction with close follow-up and supportive care until definitive stone management. Bilateral percutaneous nephrolithotomy can provide definitive surgical intervention without significant morbidity.

The Surgical Management of Urolithiasis: A Review of the Literature.

The incidence of stone disease has increased significantly in the past 30 years, with a reported prevalence of 11% of the U.S. population in 2022, up from 9% in 2012 and 5.2% in 1994.1 While prevention is a vital aspect of management, many patients present with symptomatic urolithiasis requiring surgical management. Emerging advances in endoscopy and technology has led to a dynamic shift in the surgical management of stone disease. This paper will serve as a comprehensive review to inform urologic and non-urologic medical professionals alike, as well as the layperson, on the surgical treatment of nephrolithiasis, starting from the initial evaluation, laboratory and radiographic studies, and various surgical options. Additionally, the nuances of managing the pediatric and pregnant patient with nephrolithiasis will be explored. Using the most up-to-date urologic data, our aim is to provide a comprehensive resource for readers who interact with patients experiencing acute episodes of urolithiasis.

Rare Presentation of Primary Hyperparathyroidism in a Young Woman.

Even though primary hyperparathyroidism (PHPT) is a common endocrine disorder, due to better and more regular screening, the usual presentation is only seen in less than 15% of cases of PHPT. The authors present the case of a young female patient with a previous medical history of depression and nephrolithiasis, with one year of bone pain, that had become progressively worse and disabling. In the initial work-up, several lytic bone lesions and moderate hypercalcemia were found, leading to admission of the patient in the Internal Medicine ward for investigation and treatment. The ensuing investigation revealed PHPT due to hyperfunctioning parathyroid adenoma. The patient underwent a parathyroidectomy and at the follow-up assessment two months after discharge, she reported no symptoms and a computer tomography scan showed regression of the lytic lesions. This case is a reminder that severe symptomatic PHPT, a rare form in developed countries nowadays, still exists, and even though it is a medical condition, collaboration with surgical specialties is necessary to ensure the best possible treatment and prognosis.

Complicaciones frecuentes en pacientes con nefrolitotomía percutánea / Common complications in patients with percutaneous nephrolithotomy

RESUMEN La nefrolitotomía percutánea es un procedimiento estandarizado para el tratamiento de la litiasis renal. El objetivo de esta comunicación fue describir las complicaciones que más incidieron en los pacientes que fueron atendidos en el Hospital Universitario Clínico-Quirúrgico «Arnaldo Milián Castro¼, en el servicio de Urología, de enero de 2015 a diciembre de 2019, a los cuales se les realizó nefrolitotomía percutánea, así como el tratamiento que recibieron y su evolución. Este estudio mostró bajo índice de complicaciones, lo que guarda relación con el poco tiempo utilizado para realizar esta técnica. Esto resultó beneficioso ya que contribuyó a la corta estadía hospitalaria y disminuyó el consumo de materiales e insumos médicos. También representa un gran logro para los médicos y sobre todo para el paciente, el cual puede recuperarse en un menor período de tiempo y vincularse rápidamente a su vida diaria.

ABSTRACT Percutaneous nephrolithotomy is a standardized procedure for the treatment of kidney stones. The objective of this communication was to describe complications, treatment and evolution of patients who underwent a percutaneous nephrolithotomy in the Urology service at "Arnaldo Milián Castro" Clinical and Surgical University Hospital from January 2015 to December 2019. This study showed a low rate of complications, which is related to the short time used to perform this technique. This was beneficial since it contributed to the short hospital stay and decreased the consumption of medical materials and supplies. It also represents a great achievement for doctors and above all for the patients, who can recover in a shorter period of time and be quickly returned to their daily life.

Nephrolithiasis management and outcomes in pediatric patients with limited mobility.

INTRODUCTION AND OBJECTIVES: Pediatric patients with limited lower extremity mobility may be at increased risk of developing nephrolithiasis due to bone mineral metabolic derangements. This study sought to assess whether nephrolithiasis management and related outcomes differ between ambulatory versus non-ambulatory pediatric patients. METHODS: This was a retrospective review of ambulatory and non-ambulatory pediatric patients with nephrolithiasis from 2010 to 2021 from a single tertiary care center. Demographics, surgical history, stone compositions, and 24-h urine data were reviewed. Adjusted logistic and linear regression models were utilized to assess whether mobility status was associated with nephrolithiasis-related management and outcomes, including: age at first stone; requiring surgical intervention for stones; number of surgeries; stone compositions; urine culture results; and completion of 24-h urine studies. RESULTS: Among 339 pediatric patients with nephrolithiasis, 67 (19.8%) were non-ambulatory. In adjusted analyses, non-ambulatory patients had 3.24 times greater odds of requiring surgical intervention for stones (95% CI: 1.93-6.84; p < 0.0001); among those who required surgery, non-ambulatory patients required an average of 0.82 more surgical interventions (95% CI: 0.35-1.30; p = 0.0008) than ambulatory patients. Additionally, non-ambulatory patients had 5.28 times greater odds of having a positive urine culture at the time of surgery (95% CI: 2.35-14.08; p = 0.0001) and were significantly less likely to undergo 24-h urine studies (OR: 0.35; 95% CI: 0.15-0.83; p = 0.02). Stone composition significantly varied by mobility status, with non-ambulatory patients being significantly more likely to form calcium apatite (OR: 5.1; 95% CI: 2.18-11.93; p = 0.0002) or struvite (OR 3.72; 95% CI: 1.18-11.74; p = 0.03) stones, and significantly less likely to form calcium oxalate stones (OR: 0.19; 95 CI: 0.08-0.47; p = 0.0003). Among all patients, age at first stone occurred at a median age of 13.4 years (IQR: 8.2-16.4) and did not significantly differ by mobility status (p = 0.92). CONCLUSIONS: Patients with limited mobility required surgery for nephrolithiasis at significantly higher rates and had different stone compositions than ambulatory patients. Obtaining a 24-h urine study in patients with comorbidities affecting ambulation was uncommon, compared to ambulatory patients. Similarly to ambulatory patients, pediatric patients with limited mobility who develop nephrolithiasis tend to first present with stones in early adolescence.

Diferencias entre el Urocultivo Previo y el cultivo del Catéter doble J. Implicancias clínicas / DIFFERENCES BETWEEN PREVIOUS URINE CULTURE AND DOUBLE J CATHETER CULTURE. CLINICAL IMPLICATIONS

Las infecciones urinarias complicadas, dentro de las cuales se encuentran las asociadas a catéteres, son un hallazgo frecuente de la práctica clínica. Las complicaciones infecciosas después de los procedimientos urológicos son una fuente importante de morbimortalidad y consumen múltiples recursos sanitarios. La colonización bacteriana en el catéter ureteral juega un papel esencial en la patogénesis de la infección, y el uso de profilaxis antimicrobiana en urología es controvertido. El objetivo de nuestro trabajo fue evaluar la utilidad de la profilaxis antibiótica en la extracción del catéter doble J

Complicated urinary infections, among which are those associated with catheters, are a frequent finding in clinical practice. Infectious complications after urological procedures are an important source of morbidity and mortality and consume multiple healthcare resources. Bacterial colonization in the ureteral catheter plays an essential role in the pathogenesis of infection, and the use of antimicrobial prophylaxis in urology is controversial. Te objective of our work was to evaluate the usefulness of antibiotic prophylaxis in the extraction of the double J catheter

Impact of an Acute Care Urology Service on Timelines and Quality of Care in the Management of Nephrolithiasis.

Background: The acute care surgery model has led to improved outcomes for emergent surgical conditions, but similar models of care have not been implemented in urology. Our department implemented an acute care urology (ACU) service in 2015, and the service evolved in 2018. We aimed to evaluate the impact of the ACU model on the management of nephrolithiasis. Materials and Methods: We conducted a retrospective review of all patients with urology consults in the emergency department for nephrolithiasis, who required surgical intervention from 2013 to 2019. Patients were divided into three cohorts based on date of consultation: Pre-ACU (2013-2014), Phase 1 (2015-2017), and Phase 2 (2018-2019). Results: We identified 733 patients with nephrolithiasis requiring intervention (162 pre-ACU, 334 Phase 1, and 237 Phase 2). Before ACU implementation, median time from consult to definitive intervention was 36 days. After ACU implementation, median time to intervention decreased to 22 days in Phase 1 (p < 0.001) and 15 days in Phase 2 (p < 0.001). On multivariable Cox regression, the hazard of definitive intervention improved in Phase 1 (hazard ratio [HR] 1.90, p < 0.001) and in Phase 2 (HR 1.80, p < 0.001). Rates of primary definitive intervention without initial decompression and loss to follow-up were also significantly improved, compared to the pre-ACU cohort. Conclusions: Implementation of a structured ACU service was associated with improved time to treatment for patients with acute nephrolithiasis, as well as increased primary definitive intervention and improved follow-up care. This model of care has potential to improve patient outcomes for nephrolithiasis and other acute urological conditions.

Parathyroidectomy for nephrolithiasis in primary hyperparathyroidism: Beneficial but not a panacea.

BACKGROUND: Nephrolithiasis is a classic indication for parathyroidectomy in primary hyperparathyroidism patients; however, the effects of parathyroidectomy on nephrolithiasis recurrence are not well studied. The aim was to determine effect of parathyroidectomy on time to first nephrolithiasis recurrence and recurrence rate per patient-years. METHODS: A retrospective cohort study of patients diagnosed with primary hyperparathyroidism and at least one episode of nephrolithiasis was performed. The patients were divided into observation, presurgery, and postsurgery groups. Endpoints were time to first recurrence of nephrolithiasis and average recurrence rate per patient-years. RESULTS: The cohort was comprised of 1,252 patients. In addition, 334 (27%) patients underwent parathyroidectomy and 918 (73%) were observed. The surgical and nonsurgical groups differed significantly in age, sex, Charlson, calcium, and primary hyperparathyroidism level. Overall recurrence rate was 31.3%. The 5-, 10-, and 15-year recurrence-free survival rates were 74.4%, 56.3%, 49.5%, respectively (presurgery), 82.4%, 70.9%, 62.8%, respectively (postsurgery; P < .0001), and 86.3%, 77.7%, and 70.6%, respectively (observation). The presurgery group had an increased risk of first recurrence compared with the observation group (hazard ratio 1.89; 95% confidence interval, 1.44-2.47). The average recurrence rates among all surgical patients who recurred were 1 event per 4.3 patient-years presurgery versus 1 event per 6.7 patient-years postsurgery (P = .0001). CONCLUSION: Recurrent nephrolithiasis is a significant problem in patients with primary hyperparathyroidism. Parathyroidectomy prolongs the time to first recurrence and decreases the number of re-recurrences over time but does not eliminate recurrences. Observation may also be a reasonable approach in selected patients.

The T-Tilt Position: A Novel Modified Patient Position to Improve Stone-Free Rates in Retrograde Intrarenal Surgery.

PURPOSE: Residual fragments following retrograde intrarenal surgery can lead to future stone episodes. The lower pole of the kidney presents a unique challenge as it is the most difficult location for retrograde intrarenal surgery. We investigated a modified patient position to increase stone-free rate by analyzing presence of residual fragments. We randomized patients into standard position and the T-Tilt position (15° Trendelenburg and 15° airplane away from the surgical side kidney). MATERIALS AND METHODS: In this prospective, randomized study, patients were randomized into the standard or T-Tilt position. Demographics, comorbidities and operative parameters were collected. Stone-free rate was determined with renal ultrasound and x-ray at 1-month followup. Postoperative complications were recorded up to 1 month. Variables were compared using Kruskal-Wallis test for continuous variables and chi-square test for categorical variables. RESULTS: A total of 138 patients were analyzed: 75 standard patients and 63 T-Tilt patients. The groups had similar patient and stone factors. The most common stone position was the lower pole (68.0% standard, 74.6% T-Tilt). Stone-free rates were significantly different: standard position was 76.7% and T-Tilt position was 92.1% (p=0.015). Stone-free rates for isolated lower pole stones were significantly different as well: standard position was 68.2% and T-Tilt position was 95.6% (p <0.001). Clavien-Dindo scores did not differ significantly (p=0.262). CONCLUSIONS: The T-Tilt patient position was associated with higher stone-free rates. It is an atraumatic, cost-effective technique. These results suggest that modifying patient positioning during retrograde intrarenal surgery improves stone-free rates.

Is Retrograde Intrarenal Surgery as Safe for Children as It Is for Adults?

INTRODUCTION: The primary aim of this study is to compare the efficacy and safety of retrograde intrarenal surgery (RIRS) among the children and adults with similar stone burdens and locations. Also, the secondary aim of this study is to identify the factors affecting the stone-free rates (SFRs) of RIRS. METHODS: We retrospectively compared perioperative results, SFRs, and complication rates (CRs) between pediatric (group 1, n: 55) and adult (group 2, n: 220) age groups diagnosed with kidney stones and treated by flexible ureterorenoscopy using the same instruments. Furthermore, multivariate analysis was performed to determine the factors affecting the SFR. RESULTS: A total of 275 patients (pediatric group: 55; adult group: 220) were included in this study. The mean age of pediatric and adult groups was 7.2 ± 5.3 and 43.9 ± 15.1, respectively. The mean stone size was 13.9 ± 6.6 mm in the pediatric group compared to 14.8 ± 6.7 mm in the adult group (p = 0.35). Stone localizations and number were similar. JJ stenting for passive dilatation and use of UAS were higher in the pediatric group (p = 0.002; p = 0.017). However, postoperative double pigtail stenting rate was higher in the adult group (p < 0.001). Total CR was 13.8% and mostly Clavien I-II, and no difference was observed between the 2 groups (p = 0.541). The SFRs between the groups were similar (pediatric group: 81.8%; adult group: 78.2%; p = 0.554). On multivariate analysis, stone size (p < 0.001) and lower calyx stone (p < 0.001) were the negative predictive factors for SFR. CONCLUSION: There are small technical differences between pediatric patients and adult patients in our study, but RIRS in children is as safe and efficient as it is in adults.

Gender differences in the presentation, course and outcomes of primary hyperparathyroidism.

OBJECTIVE: To investigate gender-associated differences in the presentation, course, and outcomes of primary hyperparathyroidism (PHPT). STUDY DESIGN: A retrospective institutional cohort. METHODS: The database of a tertiary endocrine institute was retrospectively screened for patients treated for PHPT in 2010-2018. Clinical, biochemical, and imaging data were collected. Presentation, management, and outcome variables were compared by gender and by age at diagnosis (<50/≥50 years). RESULTS: The cohort included 182 women and 161 men diagnosed with PHPT at age 57.6 ± 12.8 and followed for 6.3 ± 5.5 years. There were no gender differences in age at detection of hypercalcemia and basal levels of serum and urinary calcium, serum PTH, and serum 25-hydroxyvitamin D. Men had a higher prevalence of nephrolithiasis (33 % vs 21 %, p = 0.01). Women had a higher frequency of osteoporosis (65 % vs 45 %, p < 0.001), and a lower mean lumbar spine T-score at PHPT diagnosis. At last follow-up, women had worse bone mineral density (BMD) results in all measured sites (lumbar spine, femoral neck, distal radius) and more fractures (34 % vs 20 %, p = 0.004), despite more frequent and longer pharmacological treatment of osteoporosis. On analysis by age, all these gender-associated differences were statistically significant only in patients diagnosed at age ≥50 years. Parathyroidectomy was performed in 52 % of women and 42 % of men (p = 0.06). CONCLUSION: The main differences between male and female patients with PHPT are the higher prevalence, more intensive pharmacological treatment, and worse outcomes of osteoporosis in women. Tailoring the optimal medical and/or surgical treatment for fracture prevention in patients with PHPT remains a major challenge, especially in older women.

Nefrolitotricia percutánea ambulatoria: nuestra experiencia en 156 casos / Ambulatory Percutaneous Nephrolithotomy: Our experience in 156 cases

OBJETIVOS: analizar y presentar nuestros resultados en el tratamiento de la litiasis renal mediante Nefrolitotricia Percutánea (NLP) ambulatoria en un mismo centro. MATERIALES Y MÉTODOS: entre agosto de 2013 y mayo de 2017 se realizó una recolección prospectiva de datos de los pacientes sometidos a NLP ambulatoria tubeless con catéter doble J o totally tubeless por litiasis renal. Se excluyeron aquellos pacientes con score de ASA >3. Se analizaron los datos preoperatorios, intra- y posoperatorios. Se clasificaron las complicaciones de acuerdo con el sistema de Clavien modificado. Se compararon los valores de hematocrito, hemoglobina, creatininemia y uremia pre- y posoperatoria a las 48 horas. RESULTADOS: en total, se operaron 156 pacientes, a los cuales se les dio el alta el mismo día de la cirugía. La suma de los diámetros máximos de las litiasis, en promedio, fue de 26,6 mm, 32 casos de litiasis coraliforme. La posición más utilizada fue la ventral, con un tiempo promedio de cirugía de 50 minutos. Se realizó NLP tubeless en 125 pacientes y totally tubeless en 29 casos. A 40 pacientes se les colocó un tapón de Surgicel en el tracto de acceso percutáneo. La tasa libre de cálculos fue del 84%, y en pacientes con litiasis coraliforme fue del 53%. No hubo complicaciones intraoperatorias y el 80% de los pacientes no presentó complicaciones. La tasa de reinternación fue del 3%. Si bien se hallaron diferencias significativas entre los valores pre- y posoperatorios de hematocrito y hemoglobina (40% y 13,3 g/dl vs. 39% y 12,8 g/dl; p=0,0001 y 0,0001, respectivamente), estas no fueron clínicamente significativas y solamente un paciente requirió de transfusión de sangre (0,6%). CONCLUSIONES: en nuestra experiencia, la NLP ambulatoria fue segura, con tasas libres de cálculos y complicaciones similares a las realizadas con internación.

OBJECTIVES: To assess the safety and feasibility of ambulatory percutaneous nephrolithotomy (PCNL) at a single institution. METHODS: Data collected prospectively of patients submit for ambulatory PCNL tubeless or totally tubeless between August 2013 and May 2017 were review. Exclusion criteria were patients with ASA score >3. Preoperative, intraoperative, and postoperative data were collected. Complications were classified using the Clavien sistem modified for PCNL. Properative and 48hs postoperative value of hematocrit, hemoglobin, creatininemia and uremia were compare. RESULTS: One hundred and fifty five patients underwent ambulatory PCNL. All patients were discharge the same day of surgery. The median of the sum of the maximum stone diameter was 26,6mm, 32 patients had staghorn calculus. We performed the majority of the surgerys in ventral position with a median time of 50 minutes. One hundred and twenty five patients underwent tubeless PCNL and totally tubeless 29 patients. In 40 cases we used Surgicel for sealing the percutaneous tract. Overall stone-free rate was 84% and 53% in staghorn cases. There were no intraoperative complications and 80% of the patients did not have any complications. Readmission rate was 3%. There was a significant decrease in the postoperative hematocrit and hemoglobin level (40% y 13,3 g/dl vs. 39% y 12,8 g/dl; p=0,0001 y 0,0001), this was not clinically significant. Only one patient required blood transfusion (0,6%). CONCLUSION: Ambulatory PCNL is safe with a stone-free rate, readmisions and complications similar to standard PCNL.

Effect of Active Aspiration and Sheath Location on Intrapelvic Pressure During Miniaturized Percutaneous Nephrolithotomy.

OBJECTIVE: To evaluate the effects of location of the tip of percutaneous sheath and nephroscope in the collecting system together with active aspiration on the Intrapelvic pressure measurements (IPP) during miniaturized percutaneous nephrolithotomy (miniPNL). MATERIALS AND METHODS: The data of 20 patients underwent miniPNL in supine position was collected prospectively. IPP measurements were done with an 8 Fr urodynamic pressure measurement catheter in 4 different settings with respect to location of tip of sheath and nephroscope. All 4 settings were repeated with active aspiration. Totally measurements were done and compared in 8 different settings for 90 seconds in each patient. RESULTS: Highest mean IPP measurements were recorded in setting II (35.3 ± 11.8 cm H2O) where the sheath was located in the calyx and the tip of the nephroscope was in the renal pelvis. When active aspiration was applied, the mean pressure measurements were significantly lower than the counterpart settings without aspiration (all P values <.0001). When the active aspiration was applied, intrarenal pressure measurements did not exceed 40 cm H2O in any settings in any of the patients. CONCLUSION: Location of the tip of the sheath and the nephroscope has significant effect on IPP measurements. Active aspiration significantly lowers the IPP and keeps it <40 cm H2O. Endourologists should be aware of possible alterations in IPP during miniPNL and active aspiration should be kept in mind as an effective solution to decrease the risk of complications related to high IPP.

Natural history of patients with infantile nephrolithiasis: what are the predictors of surgical intervention?

BACKGROUND: We evaluated the risk factors for the requirement of surgical intervention in infants with nephrolithiasis. METHODS: The medical records of 122 (156 kidney units (KU)) infants were reviewed. The clinical features, stone characteristics, changes in stone status, and treatment protocols were noted. The stone status of the KU was categorized into 3 groups according to the change in size between the first and last ultrasound: resolution, unchanged, and growth. RESULTS: The median age was 8 months (r: 2-12). The median length of follow-up was 16 months (r: 10-36). Resolution was detected in 94 KUs (60%). Stone growth was detected in 39 KUs (25%), and stone size was unchanged in 23 KUs (15%). Surgical intervention was required in 26 patients (17%). A history of intensive care unit (ICU) follow-up and a stone size > 5 mm at time of diagnosis were defined as independent risk factors for stone growth (p = 0.005, < 0.001, respectively). The surgical intervention rate was higher in stones > 5 mm and stones with pelvic localization (p = 0.018, 0.021, respectively). Stone resolution was higher in patients with stone size ≤ 5 mm (p = 0.018). CONCLUSION: A stone size > 5 mm at the time of diagnosis and a history of ICU follow-up are independent risk factors for stone growth. Pelvic localization of stones and stones > 5 mm are associated with an increased risk of surgical intervention.

Surface analysis of ureteral stent before and after implantation in the bodies of child patients.

The aim of this work was to determine which part of a double-J ureteral stent (DJ stents) showed the highest tendency to crystal, calculi, and biofilm deposition after ureterorenoscopic-lithotripsy procedure (URS-L) to treat calcium oxalate stones. Additionally, the mechanical strength and the stiffness of DJ stents were evaluated before and after exposure to urine. Obtained results indicated that the proximal (renal pelvis) and distal (urinary bladder) part is the most susceptible for post-URS-L fragments and urea salt deposition. Both, the outer and inner surfaces of the DJ ureteral stents were completely covered even after 7 days of implantation. Encrustation of DJ stents during a 31-day period results in reducing the Young's modulus by 27-30%, which confirms the loss of DJ stent elasticity and increased probability of cracks or interruption. Performed analysis pointed to the need to use an antibacterial coating in the above-mentioned part of the ureteral stent to prolong its usage time and to prevent urinary tract infection.