Role of Endourological Procedures (PCNL and URS) on Renal Function: a Systematic Review

The impact of chronic kidney disease stages and CROES AND GSS scores on stone free rate in kidney stones

INTRODUCTION

This study evaluates the impact of chronic kidney disease (CKD) stages on stone-free rates (SFR) and renal function outcomes after percutaneous nephrolithotomy (PCNL). Additionally, it examines the predictive role of the CROES and Guy's Stone Score (GSS) systems.

METHODS

Data from 2994 patients who underwent PCNL between 2007 and 2024 were retrospectively analyzed. Patients were classified into four CKD groups based on preoperative estimated glomerular filtration rate (eGFR). SFR, complication rates, and postoperative renal function changes were assessed.

RESULTS

SFR was significantly lower in advanced CKD stages (p < 0.001), with the lowest in Group A (GFR < 30, 64.1%) and highest in Group D (GFR > 90, 79.1%). Postoperative eGFR increased in CKD stage 4-5 but declined in normal kidney function groups. Complication rates were higher in advanced CKD stages (p = 0.031). CROES and GSS scores correlated with stone complexity and surgical outcomes (p < 0.001).

CONCLUSION

Advanced CKD is associated with lower SFR, greater surgical complexity, and higher complication rates. PCNL remains an effective treatment, particularly in CKD patients, with potential postoperative renal function improvement. Utilizing predictive scoring systems can optimize patient selection and surgical planning. Further prospective studies are needed to validate these findings.

"Development and validation towards a Nomogram to predict acute kidney Injury following PCNL"

OBJECTIVES

To evaluate the occurrence, risk factors, and outcomes of post PCNL (Percutaneous Nephrolithotomy) Acute Kidney Injury (AKI), with a secondary goal of developing a nomogram for post-PCNL AKI prediction.

METHODS

A prospective observational study was conducted enrolling 333 patients who underwent PCNL between February 2022 and February 2023. Patient demographics, comorbidities, perioperative lab parameters, stone characteristics, intraoperative details, and postoperative AKI were assessed. Logistic regression analyses were employed to construct a nomogram for predicting post-PCNL AKI.

RESULTS

40 patients (12.4%) experienced postoperative AKI, with recovery observed in all cases during the 3-month follow-up. Female gender (p = 0.002), hypertension(p = 0.022), higher serum uric acid levels(p = 0.003), staghorn calculi(p = 0.001), higher Hounsfield Units(p = 0.013), bilateral PCNL(p < 0.001), larger tract size(p = 0.017), longer operative time(p < 0.001), greater stone volume(p = 0.025), higher baseline serum creatinine levels(p < 0.001), higher postoperative total leukocyte count(p = 0.005), and postoperative fever(p < 0.001) were significantly associated with the AKI group. Regression analysis identified female gender (OR = 0.26, p = 0.035), higher serum uric acid levels(OR = 1.62, p = 0.013), bilateral PCNL(OR = 12.55, p < 0.001), longer operation time(OR = 1.02, p = 0.047), and larger stone volume(OR = 1.12, p = 0.015) as independent risk factors for postoperative AKI. The internally validated nomogram(n = 70) for predicting AKI demonstrated excellent diagnostic performance, with an area under the ROC curve of 0.984(95% CI, p < 0.001).

CONCLUSION

AKI occurs in approximately 12% of patients undergoing PCNL. We identified several significant predictors of post-PCNL AKI, including female gender, hypertension, hyperuricemia, higher Hounsfield units, larger stone volume, bilateral PCNL, larger access tract size, and longer operative time. Awareness of these factors is crucial for optimizing management and improving patient outcomes.

Acknowledging acute kidney disease following ureteroscopy and laser lithotripsy: results from a tertiary care referral center

BACKGROUND

Acute kidney disease (AKD) is a recently described syndrome consisting of kidney function abnormalities lasting less than 3 months. Little is known regarding AKD following ureteroscopy (URS) and laser lithotripsy.

OBJECTIVE

To evaluate the occurrence and evolution of AKD in stone patients treated with URS.

MATERIALS AND METHODS

Data from 284 patients treated with URS for urinary stones were retrospectively analyzed. According to the KDIGO 2020 criteria, AKD was defined as postoperative acute kidney injury (AKI) occurrence, estimated glomerular filtration rate (eGFR) decrease ≥ 35%, or serum creatinine (SCr) increase ≥ 50%. AKI was defined as SCr increase ≥ 0.3 mg/dL or ≥ 50%. AKD evolution was evaluated 60 days post-URS. Data were analyzed using descriptive statistics. Univariable (UVA) and multivariable (MVA) logistic regression analyses tested the association of patients' characteristics and perioperative data with the occurrence of AKD.

RESULTS

Overall, postoperative AKD occurred in 32 (11.3%) patients. Recovery from AKD was found in 26 (82%) patients and persistent AKD occurred in 6 (18%) patients. At UVA, age at surgery (p = 0.05), baseline SCr (p = 0.02), baseline CKD category (p = 0.006), Charlson comorbidity index (p = 0.01), operative time (p = 0.04) and postoperative complications (< 0.001) were associated with AKD. At MVA, CKD category (OR 2.99, 95% CI = 1.4-6.3; p = 0.004), operative time (OR 1.01, 95% CI = 1.001-1.018; p = 0.023) and postoperative complications (OR 3.5, 95% CI = 1.46-8.49; p = 0.005) were independent predictors of AKD.

CONCLUSIONS

AKD is a frequent complication in patients treated with URS. Moreover, AKD persists in a non-neglectable percentage of patients at medium-term follow-up. Therefore, nephrological assessment should be considered, especially in high-risk patients. Current findings should be considered for the peri-operative management of stone patients.

A new alternative to percutaneous nephrolithotomy: A case report

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is a common procedure for kidney stone removal, involving a small incision in the back and insertion of a nephroscope to extract the stones. Recent advancements include super-mini PCNL, employing smaller instruments for less invasive access to the kidney. However, conventional PCNL often requires tract dilation, which can lead to potential complications.

CASE PRESENTATION

This case report presents the successful application of our surgical technique using the basic principles of PCNL with the aid of a pediatric trocar cystostomy and ultrasound guidance as a new alternative for super-mini PCNL, offering safer access with reduced bleeding risk and shorter recovery. The surgery was performed on a 55-year-old female with bilateral kidney stones, with the stone in the left kidney being larger than the one in the right kidney. The procedure was completed within 60 min without significant postoperative complications.

DISCUSSION

Our new alternative for PCNL offers benefits such as reduced invasiveness, shorter recovery time, decreased risk of complications, and minimal changes in postoperative hemoglobin levels. This new alternative can be performed in developing country hospitals that do not have the expensive PCNL equipment.

CONCLUSION

This new alternative of PCNL with pediatric trocar cystostomy proves to be effective and safe.

Holmium:yttrium-aluminium-garnet laser with MOSES technology is more efficient than thulium fibre laser in supine mini-percutaneous nephrolithotomy

OBJECTIVES

To address the paucity of literature comparing outcomes achieved with utilisation of the high-power holmium:yttrium-aluminium-garnet (Ho:YAG) laser with MOSES technology vs those achieved with the thulium fibre laser (TFL) in mini-percutaneous nephrolithotomy (PCNL).

METHODS

A retrospective review was performed of patients undergoing supine mini-PCNL between August 2021 and May 2023. Exclusion criteria were urinary diversion, simultaneous utilisation of >1 laser platform, use of any other form of fragmentation, and ureteric stones. The Ho:YAG platform (Lumenis Pulse P120H™ with MOSES technology, 120W; Boston Scientific®) and the TFL (Soltive SuperPulsed Thulium Fibre [SPTF], 60W; Olympus®) were compared. Data on stone-free rate (SFR) were determined by computed tomography performed on the first postoperative day and presented as absence of stone fragments, no fragments larger than 2 mm, or no fragments larger than 4 mm.

RESULTS

A total of 100 patients met the inclusion criteria, 51 mini-PCNLs with the Ho:YAG laser and 49 with the SPTF laser. No significant differences in demographics or stone characteristics were detected between the two groups. The Ho:YAG laser utilised less energy and time, resulting in higher ablation efficiency (P < 0.05) and less total operating time (P < 0.05). Overall, there was no difference in SFR in any category between the Ho:YAG group and the SPTF group (no fragments: relative risk [RR] 0.81, 95% confidence interval [CI] 0.59-1.12, P = 0.21; fragments <2 mm: RR 0.86, 95% CI 0.67-1.10, P = 0.23; fragments <4 mm: RR 0.96, 95% CI 0.80-1.15, P = 0.67).

CONCLUSIONS

Although we observed an equivalent postoperative SFR, this study supports a shorter operating time and greater intra-operative laser efficiency with the Ho:YAG laser over the SPTF laser in mini-PCNL.

Effect of access sheath diameter used in percutaneous nephrolithotomy on renal function: a prospective randomized study

We aimed to determine the effect of the access sheath diameter used in percutaneous nephrolithotomy (PNL) on renal function. We also investigated the predictors of impaired renal function. Data were prospectively collected from patients who underwent PNL from December 2020 to December 2021. The patients were randomized into two groups according to access sheath diameter: Group 1 (22 Fr, n = 44) and Group 2 (28 Fr, n = 44). Relative renal function (RRF) was calculated by technetium-99 m dimercaptosuccinic acid scintigraphy, and glomerular filtration rate (GFR) was calculated by diethylenetriamine pentaacetic acid scintigraphy. A difference of 5% or more in RRF was considered a significant functional change. Preoperative and postoperative Kidney Injury Molecule-1 (KIM-1) levels were measured. Preoperative demographic data and stone characteristics were similar between the groups. There were also no statistically significant differences between the groups in terms of scar development, changes in RRF, GFR, or KIM-1/creatinine (Cr) (p > 0.05). Significant deterioration in RRF was detected in a total of six (6.8%) patients, three in each group. The factors predicting loss of function were analyzed by regrouping the patients without loss of function as Group A (n = 82) and those with loss as Group B (n = 6). Only stone volume was statistically significant in multivariate analysis (p = 0.002). Access sheath diameter had no significant effect on renal function after PNL. However, the stone volume was found to independently correlate to a loss of renal function after PNL.

Ureteroscopic management in cystinuric patients: long-term results from a tertiary care referral center

OBJECTIVE

To evaluate long-term surgical and functional outcomes of cystinuric patients exclusively treated with Ureteroscopy (URS).

METHODS

Data from patients treated for cystine stones at a single academic center were retrospectively analyzed. The management protocol consisted of (i) treating symptomatic or > 7 mm stones, (ii) multi-staged URS for voluminous stones, (iii) referring patients to a dedicated nephrological clinic. The eGFR was calculated according to the MDRD formula. CKD category was assessed according to the NKF classification. Relevant CKD was defined as CKD category ≥ 3a. Descriptive statistics were used to analyze the cohort data.

RESULTS

Data from 46 cystinuric patients treated with 332 URS were available. Median age at diagnosis and at first URS in our center were 18 and 32 years, respectively. Median follow-up was 101 months. Median number of URS and recurrences per patient were 6 and 2, respectively. The median interval between the first and the last available creatinine level was 64 months. Median first and last eGFR were 72 and 74 mL/min, respectively. Overall, 83% of patients had stable or improved renal function within the study period. Ureteral stricture occurred in 3 (6.5%) patients.

CONCLUSIONS

Cystinuria requires intensive endoscopic management. Most patients treated with URS have stable or improved renal function within a long-term follow-up. CKD is a not neglectable event that potentially occurs at an early stage of life. Current findings should be considered for the surgical management of cystinuric patients.

2022 Recommendations of the AFU Lithiasis Committee: Specific cases - chronic kidney disease, bilateral stones, and solitary kidney

Chronic kidney disease, diabetes and hypertension are risk factors of kidney function impairment. The relative risk of kidney failure is 1.52 in patients with urinary stone disease. The various techniques used to remove upper urinary tract stones generally do not alter kidney function in patients with normal kidney function and may sometimes improve kidney function or slow its deterioration in patients with kidney disease. Compared to the asynchronous treatment of bilateral renal and ureteral stones, concomitant treatment is associated with higher risk of anuria and the need of additional interventions, in the absence of postoperative stenting. For the treatment of solitary kidney stones, the absence of postoperative stenting increases the risk of postoperative anuria. Moreover, the multiplication of percutaneous nephrolithotomy access tracts increases the risk of bleeding and that of kidney function impairment. METHODOLOGY: These recommendations were developed according to two methods: the Clinical Practice Recommendations (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and their adaptability to the French context.

Cystine Stones: Developments in Minimally Invasive Surgery and Their Impact on Morbidity and Stone Clearance

Cystinuria is a rare genetic condition that is responsible for cystine stones. Besides stone recurrence, patients with cystine stones have reduced health-related quality of life, increased rates of chronic kidney disease and hypertension. Although lifestyle measures, medical therapy and close follow up are essential to reduce and monitor cystine stone recurrences, surgical intervention is frequently needed for most cystinuria patients. Shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and active surveillance all have a role, and technological advances in endourology are vital in achieving a stone-free status and to prevent recurrences. The complexity of managing cystine stones necessitates a multidisciplinary team discussion, patient involvement and an individualised approach in a specialist centre for optimum management. Thulium fibre laser and virtual reality may have an increasing role in the future of cystine stone management.

Comparison of the effect of miniaturized and standard percutaneous nephrolithotomy on renal function assessed with DMSA scintigraphy

INTRODUCTION AND OBJECTIVES

We aimed to present a clinical study that compares standard and miniaturized percutaneous nephrolithotomy (PNL) effects on kidney function with scintigraphic imaging in primary kidney stone patients.

MATERIALS AND METHODS

One hundred four patients were included in this prospective study between May 2014 and February 2017. Eligible patients were divided into two groups miniaturized PNL (mPNL) and standard PNL (sPNL) with matched-pair analysis (1:1 scenario). Technetium-99m Dimercaptosuccinic Acid cortical scintigraphy imaging was performed before and after the operation.

RESULTS

There were no differences between the two groups in terms of success rate (mPNL (63.5%) vs. sPNL (71.2%), p=0.403), serum creatinine, glomerular filtration rate, split renal functions pre- and postoperatively (p≥0.05). There was no relationship between the type of operation and new scar formation (p=0.780). The rates of serious complication (grades 3 and 4 according to modified Clavien-Dindo Classification) were higher in sPNL (p=0.034). Stone burden, duration of operation, hemoglobin drop, multiple access, blood transfusion, and angioembolization were higher in patients with scarred kidneys (p<0.001, p=0.008, p=0.004, p<0.001, p=0.003, p=0.001, respectively). In multivariate analysis, only multiple access was found statistically significant for predicting new scar formation (p<0.001, OR: 24.28).

CONCLUSIONS

Miniaturized and standard PNL are reliable and successful operations for treating large kidney stones. No significant difference was found between the operation types regarding a decrease in renal function.

In Vivo Feasibility Test of a New Flexible Ureteroscopic Robotic System, easyUretero, for Renal Stone Retrieval in a Porcine Model

PURPOSE

Using a new robotic endoscopic platform system developed for retrograde intrarenal surgery (RIRS) called easyUretero (ROEN Surgical Inc.), we evaluated the feasibility and safety of renal stone retrieval in a porcine model.

MATERIALS AND METHODS

Six female pigs were used for our in vivo study. First, 0.3-cm-sized phantom stones were inserted into the kidneys of each pig via the ureteral access sheath. Next, renal stone retrieval was attempted using manual RIRS in three pigs and robotic RIRS in three pigs. Three surgeons performed extraction of 10 stones in each session.

RESULTS

The mean stone retrieval time by manual RIRS was significantly shorter than that by robotic RIRS (399.9±185.4 sec vs. 1127.6±374.5 sec, p=0.001). In contrast, the questionnaire regarding usability showed high satisfaction in the surgeons' fatigue category for surgeons using robotic RIRS. The radiation exposure dose was also lower in robotic RIRS than in manual RIRS (0.14 µSv vs. 45.5 µSv). Postoperative ureteral injury assessment revealed Grade 0 in manual RIRS cases and Grades 0, 1, and 2 in robotic RIRS cases.

CONCLUSION

The easyUretero system is a new robotic RIRS system that was developed in Korea. The results of the present study suggest that using easyUretero for stone retrieval during RIRS is safe and ergonomic.

International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNLs. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs.

Stone disease in low-middle income countries. Could augmented reality have a role in its management?

Urolithiasis is a global phenomenon. Cystolithiasis is common in parts of Africa due to low protein intake and dehydration from endemic diarrhoeal illnesses. Nephrolithiasis is less prevalent than in high income countries, probably due to a variety of lifestyle issues, such as a more elemental diet, higher physical activity and less obesity. Although renal stones are less common in low-middle income countries (LMICs), the social and economic impacts of nephrolithiasis are still considerable; many stones present late or with complications such as upper urinary tract obstruction or urosepsis. These may lead to the development of chronic kidney disease, or end-stage renal failure in a small proportion of cases, conditions for which there is very poor provision in most LMICs. Early treatment of nephrolithiasis by the least invasive method possible can, however, reduce the functional consequences of urinary stone disease. Although ESWL is uncommon, and endoscopic interventions for stone are not widespread in most of Africa, percutaneous nephrolithomy and ureteroscopic renal surgery are viable techniques in those regional centres with infrastructure to support them. Longitudinal mentoring has been shown to be a key step in the adoption of these minimally invasive procedures by local surgeons, something that has been difficult during the COVID-19 pandemic due to travel restriction. Augmented reality (AR) technology is an alternative means of providing remote mentoring, something that has been trialled by Urolink, the MediTech Trust and other global non-governmental organisations during this period. Our preliminary experience suggests that this is a viable technique for promulgating skills in LMICs where appropriate connectivity exists to support remote communication. AR may also have long term promise for decreasing the reliance upon short-term surgical visits to consolidate competence, thereby reducing the carbon footprint of global surgical education.

Comparison of mini endoscopic combined intrarenal surgery and multitract minimally invasive percutaneous nephrolithotomy specifically for kidney staghorn stones: a single-centre experience

BACKGROUND

Staghorn stones require surgical treatment to prevent serious complications. Multitract percutaneous nephrolithotomy (PNL) causes great renal parenchymal injury and blood loss. One-stage endoscopic combined intrarenal surgery (ECIRS) entails the combined use of antegrade nephroscope and retrograde flexible ureteroscope to clear the staghorn stone, which may overcome the limitations of multitract PNL. We aimed to compare the perioperative outcomes of mini ECIRS and multitract minimally invasive PNL in staghorn stone management.

METHODS

This was a retrospective single-center study of patients with staghorn stones who underwent ECIRS (n = 17) or multitract minimally invasive PNL (n = 17) between January 2018 and September 2021.

RESULTS

There was a significant between-group difference with respect to Guy's stone score. Stone size, stone burden (ECIRS group, 21.41 cm3; multitract minimally invasive PNL group, 20.88 cm3 [P = 0.94]), and degree of hydronephrosis were comparable in the two groups. There was no significant between-group difference with respect to one-step or final stone-free rates. The mean operative time was also not significantly different between the groups (ECIRS group, 140 min; multitract minimally invasive PNL group, 183 min [P = 0.63]). ECIRS was associated with significantly lesser postoperative pain (visual analog scale; ECIRS group: 0; multitract minimally invasive PNL group: 2.7 [P < 0.001]). Hemoglobin loss, postoperative blood transfusion rate, complications, and length of hospital stay were comparable in the two groups.

CONCLUSION

Both mini ECIRS and multitract minimally invasive PNL were effective and safe for the management of renal staghorn stones with comparable operation time and stone-free rate, and complications. ECIRS was associated with less severe postoperative pain.

Pharmacotherapeutic interventions for the treatment of bacterial prostatitis

INTRODUCTION

Bacterial prostatitis, acute or chronic, is one of the most prevalent urogenital infections in men. Its diagnosis requires the application of a careful methodology. Gram-negative bacilli are the most frequent causative agents, and in recent years, an increase in the frequency of multiresistant bacteria has been detected. The choice of the optimal antimicrobial treatment requires the selection of drugs with proven in vitro activity associated with good penetration into the prostatic tissue, especially in chronic forms of infection.

AREAS COVERED

The aim of this article is to summarize the current evidence regarding the pathogenesis, etiology, empirical and definitive antimicrobial therapy, and new pharmacotherapeutic interventions to improve the prognosis of bacterial acute or chronic prostatitis.

EXPERT OPINION

Bacterial prostatitis requires the application of an accurate diagnostic protocol to identify the causative agent and establish the optimal antimicrobial treatment. The structural and biochemical characteristics of prostatic tissue result in poor penetration of antimicrobials; therefore, in the choice of treatment, it is essential to select agents with proven antimicrobial activity and pharmacokinetic characteristics that ensure good and sustained concentrations in this area. Patients with chronic forms of infection require prolonged treatment, and relapses of the infectious process are frequent.

Efficacy and safety of percutaneous nephrolithotomy in patients with chronic kidney disease: Outcomes from a tertiary care center

BACKGROUND

The management of renal stone disease in the presence of chronic kidney disease is a challenging scenario, both in terms of surgical safety as well as perioperative outcomes. The aim of the present study is to study the efficacy, safety, and outcomes of percutaneous nephrolithotomy in patients with chronic kidney disease.

MATERIALS AND METHODS

A prospective study was conducted including adult patients with renal stone disease and a creatinine clearance of <90ml/min (Stage 2 CKD or more) who underwent percutaneous nephrolithotomy. Pre-operative and post-operative serum creatinine and glomerular filtration rates were compared. Patients were divided into CKD stages 1-5 having creatinine clearance >90ml/min, 60-90ml/min, 30-60ml/min, 15-30ml/min and <15ml/min respectively. Based on up migration or down migration of CKD stages, patients were classified as improved, deteriorated or stable. Peri-operative complications and outcomes were also compared.

RESULTS

A total of 185 patients with CKD stage less than or equal to 2 underwent PCNL. The mean age of the patients was 43.24+/-14.32 years. The mean preoperative estimated glomerular filtration rate was 62.88±23.42mL/min/1.73m2. Pre-operative CKD stage distribution was as follows: stage 2-121(65.4%), stage 3-34(18.4%), stage 4-24(13%) and stage 5-6(3.2%). On last follow-up of patients, the mean creatinine was 1.07±0.65 mg/dL and the mean eGFR was 82.75±31.22 mL/min/1.73m2. The median change in creatinine and mean change in GFR was 0.23 (0.16-0.27) g/dL and 19.87 ± 19.77 mL/min/1.73 m2 respectively. Improvement in kidney function with a stage down migration was seen in 115 cases(62.2%), slight improvement with no change in stage in 69 cases(37.3%) and deterioration of CKD stage was present in one case(0.5%).

CONCLUSION

Percutaneous nephrolithotomy is associated with favourable functional outcomes in chronic kidney disease patients including severe CKD(stage IV and V). Improvement or stabilization of CKD stage was seen in 99.5% patients post PCNL.

The Life and Death of Percutaneous Stone Removal: "Looking Back-Looking Forward"

Although percutaneous nephrolithotomy (PCNL) is less morbid than open surgery, it still carries risks of significant complications as well as injury to the renal parenchyma. Flexible ureteroscopic stone removal, although causes no appreciable damage to the renal parenchyma, has limitations, most notably, a lower stone-free rate than PCNL. Advances in our knowledge regarding ureteral physiology combined with technical developments applied to ureteral access sheath deployment and size may well propel retrograde intrarenal surgery to the forefront of kidney stone removal, regardless of stone size or location.

Association of Kidney Stone Disease (KSD) with Primary Gastrointestinal Surgery: a Systematic Review over Last 2 Decades

PURPOSE OF REVIEW

We aim to provide an up-to-date literature review to further characterise the association of kidney stone disease (KSD) with gastrointestinal (GI) surgery. As KSD is associated with significant morbidity, it is important to quantify and qualify this association to provide better care and management for the patient subgroup.

OBJECTIVE

To perform a systematic review of the existing literature to evaluate the association of KSD following GI surgery.

METHODS

A literature search was performed of the following databases: MEDLINE, EMBASE, Scopus, Google Scholar, Key Urology, Uptodate and Cochrane Trials from January 2000 to June 2020.

RECENT FINDINGS

A total of 106 articles were identified, and after screening for titles, abstracts and full articles, 12 full papers were included. This involved a total of 9299 patients who underwent primary GI surgery. Over a mean follow-up period of 5.4 years (range: 1-14.4 years), 819 (8.8%) developed KSD, varying from 1.2 to 83% across studies. The mean time to stone formation was approximately 3 years (range: 0.5-9 years). In the 4 studies that reported on the management of KSD (n = 427), 38.6% went on to have urological intervention. There is a high incidence of KSD following primary GI surgery, and after a mean follow-up of 3 years, around 9% of patients developed KSD. While the GI surgery was done for obesity, inflammatory bowel disease or cancer, the risk of KSD should be kept in mind during follow-up, and prompt urology involvement with metabolic assessment, medical and or surgical management offered as applicable.

Acute Kidney Injury Post-Percutaneous Nephrolithotomy (PNL): Prospective Outcomes from a University Teaching Hospital

Acute Kidney Injury (AKI) after percutaneous nephrolithotomy (PNL) is a significant complication, but evidence on its incidence is bereft in the literature. The objective of this prospective observational study was to analyze the incidence of post-PNL AKI and the potential risk factors and outcomes. Demographic data collected included age, gender, body mass index (BMI), comorbidities (hypertension, diabetes mellitus), and drug history-particularly angiotensin converting enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers and beta blockers. Laboratory data included serial serum creatinine measured pre- and postoperation (12, 24, and 48 h), hemoglobin (Hb), total leucocyte count (TLC), Prothrombin time (PT), serum uric acid and urine culture. Stone factors were assessed by noncontrast computerized tomography of kidneys, ureter and bladder (NCCT KUB) and included stone burden, location and Hounsfield values. Intraoperative factors assessed were puncture site, tract size, tract number, operative time, the need for blood transfusion and stone clearance. Postoperative complications were documented using the modified Clavien-Dindo grading system and patients with postoperative AKI were followed up with serial creatinine measurements up to 1 year. Among the 509 patients analyzed, 47 (9.23%) developed postoperative AKI. Older patients, with associated hypertension and diabetes mellitus, those receiving ACE inhibitors and with lower preoperative hemoglobin and higher serum uric acid, had higher incidence of AKI. Higher stone volume and density, staghorn stones, multiple punctures and longer operative time were significantly associated with postoperative AKI. Patients with AKI had an increased length of hospital stay and 17% patients progressed to chronic kidney disease (CKD). Cut-off values for patient age (39.5 years), serum uric acid (4.05 mg/dL) and stone volume (673.06 mm3) were assessed by receiver operating characteristic (ROC) curve analysis. Highlighting the strong predictors of post-PNL AKI allows early identification, proper counseling and postoperative planning and management in an attempt to avoid further insult to the kidney.

Comparison of antegrade and retrograde ureterolithotripsy for proximal ureteral stones: a systematic review and meta-analysis

Background

Antegrade percutaneous ureterolithotripsy (URSL) could be a treatment option for large and/or impacted proximal ureteral stones, which are difficult to treat. To review the current approach and treatment outcomes and to compare the efficacy of retrograde and antegrade URSL for large proximal ureteral stones, we evaluated the unique perspectives of both surgical modalities.

Methods

This systematic literature review and meta-analysis was performed in July 2020. Articles on human studies and treatment of ureteral stones with URSL were extracted from the PubMed, MEDLINE, Embase, Cochrane Library, Scopus, and the Japan Medical Abstracts Society databases without any language restrictions. The risks of bias for randomized controlled trials (RCTs) and non-randomized controlled trials (non-RCTs) were assessed using the Cochrane risk of tool and the Risk of Bias in Non-randomized Studies- of Interventions tool, respectively.

Results

A total of 10 studies, including seven RCTs and three non-RCTs, were selected for the analysis; 433 and 420 cases underwent retrograde and antegrade URSL, respectively. The stone-free rate (SFR) was significantly higher in antegrade URSL than in retrograde URSL (SFR ratio: 1.17, 95% CI: 1.12-1.22; P<0.001), while the hospital stay was significantly longer in antegrade URSL than in retrograde URSL (standardized mean difference: 2.56, 95% CI: 0.67-4.46; P=0.008). There were no significant differences in the operation time and the overall complication rate between the two approaches.

Conclusions

Despite the heterogeneity of data and bias limitations, this latest evidence reflects real practice data, which may be useful for decision making.