The CROES Percutaneous Nephrolithotomy Global Study: The Influence of Body Mass Index on Outcome

Safety and efficacy of percutaneous nephrolithotripsy versus retrograde intrarenal surgery for obese patients with pelvic 1.5:3 cm renal stones

BACKGROUND

Retrograde intrarenal surgery (RIRS) has recently made significant breakthroughs, drawing some attention to it as a secondary or alternative method of treating kidney stones.

OBJECTIVES

To compare the safety and efficacy of the percutaneous nephrolithotripsy (PCNL) in the prone position vs retrograde intrarenal surgery (RIRS) in surgical treatment of unilateral pelvic renal stones from 1.5 to 3 cm is size in adult obese patients with body mass index ⩾30.

METHODS

This prospective randomized comparative study was done at Helwan University Hospital. It was conducted on 120 patients with unilateral pelvic renal stones from 1.5 to 3 cm in largest diameter who was admitted through duration to compare the two procedures' differences in terms of complications, analgesic use, hospital stay, operational time, and stone-free rates.

RESULTS

There was no significant difference between the two groups as regard stone free rate and complications. Stone free rate was 91.1% in PCNL group while it was 84.5% in RIRS group (p-value = 0.314). The mean operative time for PCNL & RIRS groups was 96 ± 28.23 min and 119 ± 14.4 min, respectively (p-value = 0.026). Mean hospital stay was 3.16 ± 0.77 days in PCNL group while it was 1.19 ± 0.69 days in RIRS group (p-value < 0.001).

CONCLUSION

RIRS can be used as the first option in obese individuals with 1.5 to 3 cm renal stones is based on the satisfactory results attained in the RIRS groups.

Impact of Obesity on the Outcomes of Supine Percutaneous Nephrolithotomy: A Propensity Score Analysis

Objectives: The aim of this study was to evaluate whether obesity could influence the success and safety of percutaneous nephrolithotomy (PCNL) performed in the supine position. Patients and Methods: This prospective cohort study included 664 patients who underwent supine PCNL between September 2008 and June 2023. Patients were stratified into two groups: obese (272 patients) and nonobese (392 patients). To minimize bias, a 1:1 matching was performed between the groups based on Guy's stone score, preoperative stone burden, and potential confounding variables. Procedural success was defined as the complete absence of stones on CT performed 3 months postoperatively. Safety was assessed by the incidence of overall, infectious, and hemorrhagic complications, with complications graded using the modified Clavien-Dindo classification. Results: The obese patient group showed a significantly higher prevalence of hypertension, diabetes mellitus, and higher anesthetic risk according to the American Society of Anesthesiologists' classification. However, the complexity of the cases and the surgical technique employed were compared between the two groups. In the univariate analysis, no significant differences were observed in success rates (p = 0.118), overall complications (p = 0.222), hemorrhagic (p = 0.104), or infectious complications (p = 0.326). After matching, a significant reduction in hemorrhagic complications was identified in the obese patient group (odds ratio 0.43; 95% confidence interval: 0.18-0.97; p = 0.027). However, obesity was not associated with an increased likelihood of overall (p = 0.093) or infectious complications (p = 0.869), nor did it affect procedural success (p = 0.219). Conclusions: Obesity should not compromise the success or safety of PCNL when performed in the supine position. On the contrary, it may offer a protective effect against hemorrhagic complications. These findings suggest that supine PCNL is a safe and effective surgical option for obese patients, and obesity should not be regarded as a contraindication when the procedure is otherwise indicated.

Are very thin patients at a higher risk of complications when submitted to percutane-ous nephrolithotomy?

PURPOSE

To assess the impact of thinness on the outcome of the percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A matched case-control study was performed using a prospectively collected database of all patients who underwent PCNL between June 2011 and October 2021. The patients were stratified into two groups according to their phenotypic characteristics, arbitrarily defined according to their body mass index (BMI): <0kg/m2 (Group 1, very thin patients, G<20) and ≥25 kg/m2 (Group 2, non-thin patients, G≥25). Patients were randomly matched based on Guy's Stone Score (GSS) according to case complexity at a ratio of 1:3.

RESULTS

A total of 204 patients were enrolled in this study: 51 patients (G<20) and 153 controls (G≥25). Complications occurred in 15.2% of the patients, with 5.4% of these complications classified as major complications (Clavien grade ≥ 3). According to complications there were no significant differences between the groups. The overall complication rates were 17.6% in the G<20 and 14.4% in the G≥25 (p = 0.653). The major complication rates were 3.9% in the G<20 and 5.8% in the G≥25 (p=0.429). No differences in transfusion or urinary fistula rates were found.

CONCLUSIONS

In this study, very thin patients were not at a higher risk of complications when submitted to PCNL than in those with a BMI of ≥25 kg/m2. Apparently, this technique can be used in these patients, just as it is used in any other type of patient, independently of their BMI.

Management of Patients Receiving Anticoagulation Therapy in Dental Practice: A Systematic Review

BACKGROUND

Anticoagulant drugs are a valuable tool for minimizing thrombotic risks in at-risk patients. The purpose of this study is to conduct a literature review highlighting the management of these drugs during daily clinical dental practice.

MATERIALS AND METHODS

We limited our search to English-language papers published between 1 January 1989, and 7 March 2024, in PubMed, Scopus and Web of Science that were relevant to our topic. In the search approach, the Boolean keywords "anticoagulant AND dentistry" were used.

RESULTS

Twenty-five clinical trials were included for final review from 623 articles obtained from the databases Web of Science (83), PubMed (382), and Scopus (158), eliminating duplicates and 79 off-topic items, resulting in 419 articles after removing 315 entries and confirming eligibility. Overall, these studies support the use of local hemostatic measures to manage the risk of bleeding in patients on anticoagulant therapy undergoing dental procedures and highlight the importance of greater education and collaboration among healthcare professionals.

CONCLUSIONS

Research and clinical investigation have improved understanding and management of dental procedures in patients undergoing anticoagulant or antiplatelet therapy. Hemostatic agents, clinical protocols, risk factors, and continuous education are essential for navigating the complexities of anticoagulant therapy, ensuring optimal outcomes and enhancing patient well-being.

Is Totally Tubeless Percutaneous Nephrolithotomy a Safe and Efficacious Option for Complex Stone Disease?

Background: Percutaneous nephrolithotomy is the gold standard treatment for large, complex intrarenal stones. Historically, this was performed using a nephrostomy tube (PCN) and/or internalized ureteral stent at the end of the procedure. However, totally tubeless nephrolithotomy (tt-PCNL) is a novel technique where no tubes (no stent nor nephrostomy tube) are left post-operatively. We review the literature on this subject regarding peri-operative outcomes, post-operative outcomes, and potential complications of the procedure, discuss our technique, and make recommendations on implementation for centers not currently utilizing the procedure. Materials and methods: We performed a comprehensive search of the literature on totally tubeless nephrolithotomy using MEDLINE database search. Our search included prior review articles, meta-analyses, systematic reviews, primary research articles, case reports, and case studies. Results: In comparison to prior approaches where a stent or nephrostomy tube is placed, tt-PCNL has a similar complication rate and better post-operative outcomes. Totally tubeless PCNL has similar operative times and similar changes in hemoglobin. However, it had shorter length of stays across all studies. The mean difference in length of stay in the studies reviewed was 1.96 days. Additionally, tt-PCNL had decreased post-operative analgesic requirements and pain scores. Conclusions: This review highlights totally tubeless percutaneous nephrolithotomy as a safe and feasible surgical technique with improved outcomes in properly selected patients.

Ultrasound-guided percutaneous nephrolithotomy (PCNL) success rates in patients with elevated body mass index: a comparative study

Percutaneous nephrolithotomy (PCNL) is considered gold standard treatment of renal stones larger than 20 mm. Several studies have shown that ultrasound guidance during this procedure is more effective and safer than fluoroscopy. A higher body mass index (BMI) can make ultrasound-guided renal access more difficult and unsuccessful. We present a prospective analysis and comparison of ultrasound-guided PCNL in patients with normal and increased body mass index. We performed a prospective comparison of patients who underwent ultrasound-guided PCNL to remove renal stones by a single surgeon between 2020 and 2022. Patients with BMIs greater than 30 (mean 33.87-obese) were compared to those with BMIs less than 30 (mean 25.69-non-obese). Demographic, perioperative, and follow-up data were collected, analyzed, and included in this study. Total of 98 consecutive patients, with 49 patients in each group were analyzed. No statistically significant differences were observed in terms of stone volume (P = 0.085), stone density (P = 0.5590), location of renal access (P = 0.108), surgery duration (P = 0.38), blood loss (P = 0.54), or laboratory changes after surgery (P = 0.60). 87.76% of obese patients were stone free per CT scan at follow-up, compared to 73.47% of normal-weight patients (P = 0.1238). According to Clavien-Dindo classification, six patients in the non-obese group experienced grade II (10%) and grade III (2%) complications, as opposed to six patients in the obese group with grade I (2%), grade II (6%), and grade III (2%) complications. There was no significant correlation between body mass index and the success or safety of ultrasound-guided PCNL. Although more challenging, a higher BMI should not be an impediment to performing this approach. This method is safe, with no increased incidence of postoperative complications or compromise in stone-free status postoperatively and can diminish or avoid both patient's and medical team's exposure to ionizing radiation.

Mini-Percutaneous Nephrolithotomy Outcomes in the Obese Population: A Retrospective Review

Introduction and Objectives: Mini-percutaneous nephrolithotomy (PCNL) has gained popularity over the last decade due to its stone-free rate comparable to traditional PCNL but with decreased risk of complications. While the data on mini-PCNL has been favorable thus far, no study today has evaluated outcomes in obese patients. Methods: All patients undergoing mini-PCNL at our institution since we began its use in 2019 were included in this study. Mini-PCNL was defined as access sheath ≤22F in size. An obese group with body mass index (BMI) ≥30 was compared to a nonobese group with BMI <30. A patient was considered relatively stone free if residual fragments were <4 mm on follow-up CT with ≤3 mm cuts. Fisher exact test was used to compare dichotomous differences between variables, and t-test to compare continuous variables. Results: We identified 67 patients who underwent mini-PCNL during the study period with 33 patients in the obese group. Median BMI in the obese group was 36.4 kg/m2 compared to 25.05 kg/m2 in nonobese. There were no blood transfusions in either group during the study period. There was no statistical difference between the obese vs nonobese group for age, access sheath size, change in hemoglobin, same day discharge, percent relatively stone free, emergency department visit within 30 days, and median largest single stone diameter. There was a significant difference in the sum of all treated stone diameter in the obese group (median 15 mm) vs nonobese (median 18 mm, p = 0.02) (Table 1). Conclusion: Mini-PCNL appears to be equally safe and effective in obese and nonobese patients alike. While there was a statistically significantly higher amount of overall stone burden in the nonobese groups, the overall difference is not clinically significant. Further research is needed to validate our experience.

Comparison Between Percutaneous Nephrolithotomy and Retrograde Flexible Nephrolithotripsy in Obese Patients with 2 - 4 cm Renal Stones

Background: Nowadays, because of remarkable advancements in retrograde intrarenal surgery (RIRS), modest attention toward this procedure as the second or alternative choice for renal stones treatment has been drawn. Objectives: In the present study, we compared RIRS and percutaneous nephrolithotomy (PCNL) outcomes in treating obese patients with 2 - 4 cm renal stones. Methods: Eighty-two patients who underwent PCNL (n = 40) and RIRS (n = 42) between June 2015 and December 2018 at the Department of Urology of Sina Hospital were enrolled in our retrospective cohort study. Results: After the first surgery session, stone-free rates for the RIRS group were 92.9% and for the PCNL group was 95% (P value = 0.52). The mean operation time for the RIRS and PCNL groups were 71.6 ± 11 and 93.3 ± 12.2, respectively (P < 0.001). The hospitalization stay for all of the PCNL group was more than 1 day (mean = 2.5 days); however, that for the majority of the RIRS group was less than 1 day (P < 0.001). The analgesic use in the RIRS group was significantly lower than in the PCNL group (9.0 ± 5.5, 61.8 ± 13.6, respectively; P < 0.001). The overall complication rates were higher in the RIRS group. However, none of them were statically significant (P > 0.05). Conclusions: According to satisfactory outcomes obtained in the RIRS groups, it can be concluded that RIRS can be applied as an alternative or even the first choice in obese patients with 2 - 4 cm renal stones.

Effect of Body Mass Index on Outcomes of Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis

Objective

The current study aimed to assess the efficacy and safety of percutaneous nephrolithotomy (PCNL) in obese and overweight individuals based on body mass index (BMI).

Methods

We electronically explored the databases of PubMed, CENTRAL, ScienceDirect, Embase, and Google Scholar databases for all types of comparative studies investigating the role of BMI on PCNL outcomes. Only studies defining obesity as >30 kg/m² were included. Efficacy outcomes were stone-free rates and operating time while safety outcomes were complications and length of hospital stay (LOS).

Results

Eighteen studies with 101,363 patients were included. We noted no difference in the stone-free rates after PCNL for morbid obese vs normal BMI patients (OR: 0.78 95% CI, 0.57, 1.08 I²= 7% p = 0.13), overweight vs normal (OR: 1.01 95% CI, 0.89, 1.15 I²= 1% p = 0.83) and obese vs normal patients (OR: 1.00 95% CI, 0.87, 1.16 I²= 0% p = 0.95). PCNL operative time was significantly increased in morbid obese (MD: 9.36 95% CI, 2.85, 15.88 I²= 76% p = 0.005) and obese patients as compared with normal patients (MD: 2.15 95% CI, 1.20, 3.10 I²= 0% p < 0.00001), but not for overweight patients. There was no difference in the odds of complications between morbid obese vs normal (OR: 1.26 95% CI, 0.93, 1.72 I²= 0% p = 0.13), overweight vs normal (OR: 1.11 95% CI, 0.96, 1.28 I²= 0% p = 0.15), and obese vs normal patients (OR: 1.07 95% CI, 0.91, 1.27 I²= 0% p = 0.40). LOS was significantly reduced in obese patients (MD: −0.12 95% CI, −0.20, −0.04 I²= 0% p = 0.004) as compared to normal patients, but not for morbid obese or overweight patients.

Conclusion

PCNL has similar efficacy and safety in morbidly obese, obese, and overweight patients as compared to normal BMI patients with no difference in the stone-free and complication rates. Evidence suggests that operating time is increased in morbidly obese and obese patients and the latter may have shorter LOS.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, identifier: CRD42022313599.

Retrograde intrarenal surgery is a safe procedure in severe obese patients. Is it reality or prediction? A propensity score-matching analysis from RIRSearch study group

OBJECTIVE

The aim of the study was to assess whether severely obese patients have an increased risk of complications during and after retrograde intrarenal surgery.

MATERIALS AND METHODS

The data of 639 consecutive patients undergoing retrograde intrarenal surgery for the treatment of upper tract urinary stones were analyzed retrospectively. The patients were divided into two groups according to their body mass index numbers (Group 1, <35; Group 2, ≥35). The patients' demographics, stone characteristics, operative outcomes, and complication rates were compared between the groups. The primary objective was to examine whether the intraoperative and postoperative complication rates were higher in patients with a body mass index of ≥35 kg/m2.

RESULTS

After matching of confounding factors, Group 1 comprised 135 patients, and Group 2 comprised 47 patients. The baseline characteristics were similar between the groups. There were no significant differences between groups for intraoperative complication rates (11.8% and 12.8%, respectively; p=0.97). There was statistically significant difference in favor of Group 2 for postoperative complication rates (12.6% and 29.7%; respectively, p<0.01), overall complication rates (22.9% and 38.2%; respectively, p=0.02), mean operation time (56.15 minute vs 66.45 minute; respectively, p= 0.01) and length of stay (1.4 days vs 2.1 days; p=0.03). Stone free rates (75.5% vs 85.1%; respectively, p=0.17) did not differ between groups.

CONCLUSIONS

Retrograde intrarenal surgery is an efficient and feasible treatment option for upper urinary tract stones in severe obese patients. However, higher possibility of postoperative, especially infectious, complication rates should be taken into account in these patients.

A prospective, observational study to assess the feasibility and safety of supine percutaneous nephrolithotomy under regional anesthesia for obese patients with a body mass index ≥30

Introduction

Besides being a risk factor for urolithiasis, obesity is a challenge in the treatment of urolithiasis from the perspective of both the surgeon and the anesthetist. In this study, we tried to assess the feasibility and safety of supine percutaneous nephrolithotomy (PCNL) under regional anesthesia in obese patients with a body mass index (BMI) ≥30.

Methods

This was a prospective observational study and included 51 obese patients (BMI ≥30 kg/m²) with renal stones planned for PCNL. All patients underwent supine PCNL under regional anesthesia with the standard technique. A decision for totally tubeless or a tubeless PCNL was made at the end of the procedure and the intraoperative and postoperative data were recorded. All patients underwent computed tomography (CT) imaging at 1 month after surgery to assess the stone-free status and the need for additional treatment.

Results

The mean age of the patients was 53.2 ± 8.09 years, and the mean BMI was 34.4 ± 2.369 kg/m². The mean operative time was 73.3 ± 26.2 min, the mean hospital stay was 58.3 ± 22.1 h, and the mean postoperative Visual Analog Score (VAS) for pain was 3.8 ± 1.4. The stone-free rate was 68.6% on the follow-up CT performed after 1 month, and 31.4% of the patients had significant residual fragments which required re-treatment either by retrograde intrarenal surgery (RIRS) in 19.6% (either as primary RIRS for the residual calculi in one patient [1.9%] or as RIRS for post shock wave lithotripsy (SWL) or alkalinization failure in 9 patients), SWL in 21.6%, or urine alkalinization in 7.8%.

Conclusion

Supine PCNL under regional anesthesia, in this subgroup of obese patients, was found to be feasible and safe with satisfactory stone-free rates and minimal postoperative pain.

Percutaneous nephrolithotomy outcomes based on body mass index: A 5-year retrospective study in an Indonesian tertiary hospital

Objectives:

The aim of this study was to evaluate the impact of body mass index (BMI) on percutaneous nephrolithotomy (PCNL) outcomes and complications for nephrolithiasis.

Patients and methods:

Patients with a history of PCNL surgery from 2012 to 2017 in Dr. Soetomo General-Academic Hospital were retrospectively evaluated. Patients were then categorized into four groups: underweight (BMI <18.5 kg/m2), normal (BMI 18.5 to 24.99 kg/m2), overweight (BMI ⩾25–29.9 kg/m2), and obese (BMI ⩾30 kg/m2). The association between BMI, subjects’ characteristics, length of stay, stone-free rate (SFR), and complications were analyzed using one-way analysis of variance (ANOVA) and univariate logistic regression.

Results:

The study included 430 male patients (58%) and 310 female patients (42%). They were classified based on their BMI into underweight ( n = 5, 1%), normal weight ( n = 291, 39%), overweight ( n = 271, 37%), and obese ( n = 173, 23%) groups. The underweight BMI group had a higher average blood loss ( p=0.002) compared to the other groups; however, the univariate logistic regression showed that BMI had no significant effect on SFR ( p=0.491).

Conclusion:

PCNL is safe and feasible to be performed in patients with different BMI as obesity has no impact on the outcomes and complications associated with PCNL.

Level of evidence

3

Does body mass index impact the efficacy and complication rate of mini-percutaneous nephrolithotomy?

Aim:

This was a retrospective cohort study exploring the efficacy of mini-percutaneous nephrolithotomy in obese patients and whether stone clearance, complication rate and length of stay is impacted by an increasing body mass index.

Method:

Data was collected retrospectively for all mini-percutaneous nephrolithotomies performed at a single centre over a 21-month period commencing March 2017. The primary outcomes included length of stay, stone clearance rates and complications.

Results:

Fifty-eight percutaneous nephrolithotomies were undertaken during the study period and of these cases 81% of patients had a body mass index of 25 or greater. The stone clearance rate was 83%. However, severely obese patients were noted to have a lower stone clearance rate. No complications occurred in the normal body mass index cohort. However, there was no difference in the complication rate for the remaining groups. Post-operative stay was approximately 3 days.

Conclusion:

This study demonstrates that supine mini-percutaneous nephrolithotomies are a safe option in obese patients with no increased risk of serious complication. Whilst stone clearance rates were lower in the severely obese category, clearance was complete in the majority of cases.

Level of evidence:

3

Impact of weight on stone-free rate during percutaneous nephrolithotomy

Background

To assess Impact of weight on stone-free rate during percutaneous nephrolithotomy.

Methods

Hundred and twenty-three PNL procedures were done between January 2016 and July 2017. The patients were divided into four groups according to the World Health Organization (WHO) classification of body mass index (BMI): < 25 ((group 1, average)), 25–29.9 (group 2, overweight), 30–39.9 (group 3, obese), and ≥ 40 kg/m2 (group 4, morbidly obese). All groups were compared as regarding preoperative variables, intra-operative procedure and postoperative results.

Results

The non-obese groups were younger in age than obese and morbid obese groups (P = 0.005). The difference in BMI was statistically significant between non-obese and obese groups (P = 0.0001). Most of females gender were obese and morbid obese (P = 0.0001) and most of the obese patients had left-sided renal stone (P = 0.001). Most of overweight and obese groups had radiopaque stones (P = 0.02). There were no statistically significant differences between all groups as regarding co-morbidity, stone size, stone locations, and hydronephrosis grade. Operative time (P = 0.034), length of hospital stay (P value = 0.014) and fluoroscopy time (P = 0.0001) were statistically significant differences between all groups. Number of accesses, access site, postoperative hemoglobin drop, post- operative complications, fate of residual stones and stone-free rate were not statistically significant differences between all groups. BMI was correlated with mean fluoroscopy time and mean hospitalization duration in our study as the time of hospitalization and time of x-ray exposure increase with obesity.

Conclusion

PNL is a safe and effective procedure for obese patients. BMI do not predict clearance post PNL.

Influence of Body Mass Index on the Surgical Outcomes of Flexible Ureteroscopy for Pediatric Upper Urinary Tract Aalculi-A Single Surgeon Experience

OBJECTIVE

To examine the association between body mass index (BMI) and surgical outcomes of flexible ureteroscopy (FURS) for pediatric upper urinary tract calculi and to estimate the influence of BMI percentile on the learning curve of pediatric FURS.

MATERIALS AND METHODS

We reviewed our prospectively maintained database containing children who had kidney or ureteral stones from June 2014 to April 2019. We calculated BMI and plotted it on the Centers for Disease Control and Prevention growth chart for sex and age to estimate BMI percentile. Patient demographics, intraoperative data, stone characteristics, stone-free rate (SFR), and complication rate (CR) were analyzed. Learning curves stratified by BMI percentile groups were generated.

RESULTS

The final analysis included 161 children, of whom 63 (39.1%) had upper body weight percentile (UBW), 64 (39.8%) had normal body weight percentile (NBW), and 34 (21.1%) had lower body weight percentile (LBW). The median stone burden of the 3 groups were 1.14 (IQR 0.50-3.41), 1.13 (IQR 0.70-3.14), and 0.95 (IQR 0.50-1.77), respectively (P = .17). The SFRs were 90.5% (57/63) in the UBW group, 81.2% (52/64) in the NBW group and 70.6% (24/34) in the LBW group (P = .04). The CRs were 15.9% (10/63), 21.9% (14/64), and 29.4% (10/34), respectively (P = .29). The learning curves showed that the SFR of FURS could be improved after about 100 cases. And decreasing BMI could steepen the learning curve of SFR.

CONCLUSIONS

BMI is associated with the SFR of FURS. LBW children had the lowest SFR compared to UBW and NBW children. Lower BMI percentile makes the success of FURS more challenging.

Risk factors of infectious complications after retrograde intrarenal surgery: a retrospective clinical analysis

OBJECTIVE

Stone disease is one of the most common afflictions in modern society. Complications following retrograde intrarenal surgery (RIRS) vary considerably, and small-diameter ureteral access sheaths are reportedly significantly associated with rates of infectious complications following RIRS. This study aimed to explore additional risk factors for infectious complications after RIRS.

METHODS

This study retrospectively analyzed 602 patients who underwent RIRS between December 2016 and October 2019 at the First Affiliated Hospital of Fujian Medical University. All flexible ureteroscopic lithotripsy processes were conducted with patients under general anesthesia in the low lithotomy position. Postoperative systemic inflammatory response syndrome (SIRS) was diagnosed; statistical analyses comprised two-way analysis of variance (ANOVA) and one-way multivariate ANOVA.

RESULTS

The incidence of infectious complications after RIRS was 7.14%. Operative time was an independent risk factor that increased the risk of infection. Stone size >2 cm was observed in 153 (27.37%) patients in the SIRS group and 29 patients (67.44%) in the non-SIRS group.

CONCLUSIONS

Findings in the literature suggest that early antibiotic treatment and active fluid therapy might lower the rate of infectious complications after RIRS. Our results indicate that extended operative time and increased stone size may be risk factors for infectious complications after RIRS.

Impact of Obesity on Outcomes of Supine Percutaneous Nephrolithotomy

Objectives: To determine whether obesity has an impact on the outcomes of supine percutaneous nephrolithotomy (PCNL). Patients and Methods: We retrospectively evaluated a prospectively created database of patients who underwent PCNL in the supine position from June 2009 to June 2014. The patients were divided into two groups according to their body mass index (BMI): <30 kg/m² (group 1, nonobese) and ≥30 kg/m² (group 2, obese). Pre, peri, and postoperative data were analyzed. Stone complexity was classified according to Guy's stone score. The primary endpoint was the absence of stone fragments of ≥4 mm on CT scans at postoperative day 1. Complications were graded according to the modified Clavien classification. Results: Of the 401 patients, 307 (76.6%) were nonobese and 94 (23.4%) were obese. Regarding demographic and stone characteristics, group 2 (BMI ≥30 kg/m²) had a higher percentage of female patients (67.3% vs 50.4%, p = 0.002) and a higher mean BMI (34.8 vs 24.5 kg/m², p < 0.001) than group 1. Success rates were not statistically different between the groups (group 1 = 61.8%, group 2 = 51%, p = 0.08). There were no differences in the transfusion rate (group 1 = 2.9%, group 2 = 4.2%, p = NS) or total number of complications greater than Clavien grade 1 (group 1 = 13.6%, group 2 = 13.8%, p = NS). Conclusion: In a retrospective study of 400 patients undergoing PCNL, the outcomes were not different between nonobese and obese patients. To our knowledge, this is the first study evaluating these outcomes for PCNL performed in the supine position. Further multicenter and prospective studies are necessary to verify these findings.

Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy

OBJECTIVES

To compare clinical outcomes in patients who underwent percutaneous nephrolithotomy (PCNL) with renal tract dilatation performed under fluoroscopic guidance vs renal tract dilatation with ultrasound guidance.

PATIENTS AND METHODS

We conducted a prospective observational cohort study, enrolling successive patients undergoing PCNL between July 2015 and March 2018. Included in this retrospective analysis were cases where the renal puncture was successfully obtained with ultrasound guidance. Cases were then grouped according to whether fluoroscopy was used to guide renal tract dilatation or not. All statistical analyses were performed using Stata version 15.1 including univariate (Fisher's exact test, Welch's t-test) and multivariate analyses (binomial logistic regression, ordinal logistic regression, and linear regression).

RESULTS

A total of 176 patients underwent PCNL with successful ultrasonography-guided renal puncture, of whom 38 and 138 underwent renal tract dilatation with fluoroscopic vs ultrasound guidance, respectively. There were no statistically significant differences in patient age, gender, body mass index (BMI), preoperative hydronephrosis, stone burden, procedure laterality, number of dilated tracts, and calyceal puncture location between the two groups. Among ultrasound tract dilatations, a higher proportion of patients were placed in the modified dorsal lithotomy position as opposed to prone, and a significantly shorter operating time was observed. Only modified dorsal lithotomy position remained statistically significant after multivariate regression. There were no statistically significant differences in postoperative stone clearance, complication rate, or intra-operative estimated blood loss. A 5-unit increase in a patient's BMI was associated with 30% greater odds of increasingly severe Clavien-Dindo complications. A 5-mm decrease in the preoperative stone burden was associated with 20% greater odds of stone-free status. No variables predicted estimated blood loss with statistical significance.

CONCLUSIONS

Renal tract dilatation can be safely performed in the absence of fluoroscopic guidance. Compared to using fluoroscopy, the present study demonstrated that ultrasonography-guided dilatations can be safely performed without higher complication or bleeding rates. This can be done using a variety of surgical positions, and future studies centred on improving dilatation techniques could be of impactful clinical value.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CT-guided nephrostomy-An expedient tool for complex clinical scenarios

INTRODUCTION & OBJECTIVES

Percutaneous nephrostomy [1] has emerged as a pivotal approach in the therapeutic management of the obstructed urinary tract. A consecutive incorporation of ultrasonic and radiographic guidance, the approach experienced an almost ubiquitious distribution while most centers currently applying either one or both of these tools jointly. However, success of ultrasound-guidance is limited in obese patients and non-dilated uropathy. In turn, fluoroscopy usually requires an opacification of the urinary collecting system by intravenous or antegrade contrast media injection, which might be harmful for already impaired renal function, raise intrapelvic pressure and augment the risk of sepsis and hemorrhage. CT-guided PCN aids in overcoming these limitations. In the current study, we present the experience of a tertiary referral center with this technique.

MATERIALS & METHODS

Epidemiological and clinical data of all patients treated with a CT-guided PCN of native kidneys at the University Hospital Frankfurt between October 2003 and October 2013 were retrospectively collected from the patient charts. Procedural parameters including radiological aspects, technical and therapeutic success, complication and mortality rate have been analyzed statistically.

RESULTS

In total, 140 PCN procedures have been performed in 77 patients with a median age of 69 (± 13). The median body mass index was 27 with 66.6% of patients being overweight or obese. Charlson comorbidity index was 7 ranging 0-16. Indications for PCNs were obstructive uropathy (62.9), urine extravasation (22.9%), urinary tract fistulas (11.4%) and technical reasons (2.8%). In 68.8% of patients, initial diagnosis was malignancy. 56.4% of kidneys were non-dilated before puncture. In 78.4% prone position, otherwise supine oblique position (17.3%) or supine position (4.3%) was used. 71.4% of PCNs were carried out solely under local anesthesia. Technical success has been achieved in 90% with a complication rate of 3.6% (all grade minor B) and was not significantly different between dilated and non-dilated kidneys. 42.9% of fistulas and 64.3% of urinary tract leakages, healed after PCN placement. 30 days mortality rate was 5.2% without being directly associated with the PCN procedure itself.

CONCLUSION

CT-guided PCN is a feasible approach associated with low morbidity. It is particularly useful in complex clinical scenarios e.g. critically ill, newly operated or obese patients as well as non-dilated kidneys. Moreover, it represents a minimally-invasive option for treating leakages and fistulas of the urinary tract.

Current trends of percutaneous nephrolithotomy in a developing country

Introduction

To present the current practice patterns on percutaneous nephrolithotomy (PCNL) in a developing country.

Materials and Methods

A survey was offered to Brazilian urologists during the II International Endourology Symposium held in Sao Paulo, in 2015. The first seven questions were related to demographic data while the 20 remaining were directed to urologists who performed PCNL.

Results

From 250 participants, 100 replied to the survey, 81% performed PCNL and 60.4% of performers had been in practice for less than 15 years. Eighty-one percent were trained in the prone position and 64% in supine. PCNL was learned during the residency in 66.7% and 2.5% had fellowship training. Prone position was the preferred decubitus for simple or complex calculi, though for obese patients there was no difference. Younger surgeons prefer supine while older surgeons prefer prone. The access was obtained by the surgeon in all cases, 96.3% use fluoroscopy and 3.7% prefer ultrasonography. Forty-seven percent use ultrasonic lithotripters and 4.1% laser. For kidney drainage, 71.6% place a nephrostomy tube. Double J stent is left in 77%. The postoperative image method was CT for 50%. Colonic injury was reported by 25%, predominantly in the senior group without statistically difference between positions.

Conclusions

From a selected group of urologists, we observe that Brazilian urologists usually gain their own access for PCNL guided by fluoroscopy. They predominantly prefer the prone position, use fascial dilators, ultrasonic lithotripters and place a nephrostomy tube when exiting the kidney. Fellowship programs, ultrasonography, flexible nephoscopy and tubeless procedures could be encouraged.

Comparative study of the treatment of 20-30 mm renal stones with miniaturized percutaneous nephrolithotomy and flexible ureterorenoscopy in obese patients

PURPOSE

To evaluate and compare flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (mPNL) for 20-30 mm renal stones in obese patients regarding efficacy and safety.

METHODS

Between May 2011 and June 2017, 254 obese patients who had 20-30 mm kidney stone were consecutively included in the study; 106 patients underwent mPNL and 148 underwent f-URS by the same surgeon. The following parameters were retrospectively assessed: patient and stone characteristics, surgical details, perioperative outcomes, and stone-free rates (SFR).

RESULTS

F-URS group was similar to mPNL group in terms of the mean duration of surgery (92.8 ± 26.1 vs 87.4 ± 31.5 min, P = 0.137) and the final SFR (89.1 vs 92.5%, P = 0.381). The f-URS group had significantly shorter postoperative stay (1.0 ± 0.8 vs 4.3 ± 1.7 days, P < 0.001) and lower postoperative complications (11.5 vs 26.4%, P = 0.002). However, the f-URS group had a lower SFR after first session (67.2 vs 87.4%, P < 0.001) and needed more number of procedures (1.5 ± 0.4 vs 1.3 ± 0.4, P < 0.001) than the mPNL group.

CONCLUSIONS

MPNL has a higher efficacy (higher SFR after first session and lower number of procedures); however, f-URS offers advantages regarding safety (lower complication rate). Therefore, both options can be offered to obese patients with renal stones from 20 to 30 mm in size. Nevertheless, these results must be confirmed by further prospective randomized trials.

Comparison of the outcomes of complete supine percutaneous nephrolithotomy in patients with radiopaque and radiolucent kidney stones

Objective

This study compared the stone opacity effect in patients who had radiopaque and radiolucent stones in percutaneous nephrolithotomy (PCNL) results.

Material and methods

The medical records of 171 complete supine PCNL procedures were gathered. Patients were categorized into two groups: those with radiopaque (n=141) and those with radiolucent (n=30) stones. Kidney, ureter and bladder x-ray was done a day after PCNL and Ultrasound imaging was done two weeks later to evaluate the stone free rate. A stone free result was defined as having less than 4 mm residual stone size. Outcome parameters were compared by univariate analysis and those which were significantly different between the two groups were assessed by multivariate binary logistic regression analysis.

Results

There were no significant differences in age, sex, body mass index, hypertension, diabetes mellitus, pre-surgery hemoglobin, pre-surgery serum creatinine, stone and also surgery-related parameters between the two groups. Stone free rate, surgery time, complication-related parameters, hemoglobin drop, serum creatinine and glomerular filtration rate (GFR) changes were similar in both groups based on univariate analysis. The radiopaque group had higher post-surgery GFR (p=0.04) and longer hospital stay (p=0.009). However, opacity had no effect on these outcomes after multivariate analysis. Higher post-surgery GFR was seen in patient with higher GFR before surgery (p<0.0001). Also, higher hemoglobin before surgery was correlated with less hospital stay (p=0.001).

Conclusion

The complete supine percutaneous nephrolithotomy outcomes are similar in patients with radiopaque and radiolucent stones.

Effects of body mass index on the outcomes of percutaneous nephrolithotomy

OBJECTIVE

To examine the the effect of body mass index (BMI) on PNL results and complications with a large number of patients.

MATERIALS AND METHODS

A total of 958 patients were included in the study, who underwent percutaneous nephrolithotomy in our clinic between 2008 and 2015. Patients were divided into 2 groups according to their body mass index. Patients with a BMI < 30 kg/m2 were classified as group 1 (n:676) and patients with a BMI ≥ 30 kg/m2 were classified as group 2 (n:282). Achieving stone-free status or having residual stones of ≤ 4 mm were considered as operational success.

RESULTS

The mean age was 47.9 years for group 1 and 48.9 years for group 2 patients. At postoperative first month CT analysis, residual stone was not observed in 466 patients (69%) of group 1 and 20 (72%) patients of group 2. There was no significant difference between the groups in terms of stone-free status (p=0.348). There was no significant difference between two groups complications. Also, there was no difference between the groups for requiring additional intervention (p=0.924). No other complications were observed in the patients.

CONCLUSIONS

BMI does not affect the outcomes of percutaneous nephrolithotomy as well as complication rate.

Skin to calyx distance is not a predictive factor for miniaturized percutaneous nephrolithotomy outcomes

Objective

To evaluate the predictive value of the distance from skin to calyx (SCD) on the outcome and complication rates of patients undergoing mPNL.

Materials and Methods

Patient’s charts, who had undergone mPNL between June 2012 and June 2015, were analyzed retrospectively. Patients who had a preoperative computerized tomography (CT) were enrolled into the study. Two separateurologists evaluated the CT scans and calculated the SCD defined as the distance between the skin and surface/lateral edge of the calyx, which was the preferred site of entry for percutaneous access. The average value of the two measurements was included inthe final analysis to avoid bias. The mean SCD was 75mm. According to the median SCD value, patients were divided into two groups: group 1 (SCD ≤75) and group 2 (SCD >75).

Results

A total of 140 patients and 130 patients were enrolled in groups 1 and 2, respectively. The mean operation time and the mean fluoroscopy time was significantly longer in group 2 (p:0.004 vs. p:0.021). The rate of blood transfusion was significantly higher in group 1 (6 patients). None of patientsin group 2required blood transfusion (p:0.017). Stone-free status after a single session of mPNL was 67.1% in group 1 and 75.4% in group 2 (p:0.112). After additional procedures, stone-free rates increased to 84.3% and 85.4% in group 1 and group 2, respectively (p:0.802).

Conclusion

Our study demonstrated that longer SCD was not a predictive factor for stone-free rates after mPNL. However, SCD over 75mm was associated with longer operation time and fluoroscopy time with lower rates of transfusion.

Predictability and Practicality of Image-Based Scoring Systems for Patient Assessment and Outcome Stratification During Percutaneous Nephrolithotomy: a Contemporary Update

Preoperative nomograms offer systematic and quantitative methods to assess patient- and stone-related characteristics and their impact on successful treatment and potential risk of complication. Discrepancies in the correlation of perioperative variables to patient outcomes have led to the individual development, validation, and application of four independent scoring systems for the percutaneous nephrolithotomy: Guy's stone score, S.T.O.N.E. nephrolithometry, Clinical Research Office of the Endourology Society nomogram, and Seoul National University Renal Stone Complexity. The optimal nomogram should have high predictive ability, be practically integrated into clinical use, and be widely applicable to urinary stone disease. Herein, we seek to provide a contemporary evaluation of the advantages, disadvantages, and commonalities of each scoring system. While the current data is insufficient to conclude which scoring system is destined to become the gold standard, it is crucial that a nephrolithometric scoring system be incorporated into common practice to improve surgical planning, patient counseling, and outcome assessment.

Comparison of STONE, CROES and Guy's nephrolithometry scoring systems for predicting stone-free status and complication rates after percutaneous nephrolithotomy in obese patients

In this study, we aim to evaluate the accuracy of STONE (stone size, tract length, obstruction, number of involved calyces, and essence/stone density), Clinical Research Office of the Endourological Society (CROES), and Guy's nephrolithometry scoring systems (NSS) in obese patients. The charts of patients who underwent percutaneous nephrolithotomy (PNL) between June 2008 and June 2016 were retrospectively analyzed. Calculations of the STONE, CROES, and Guy's NSS were performed by a resident who was well informed regarding each NSS. Patients were classified under nine scores according to STONE, four grades according to CROES, and four grades according to Guy's NSS. In total, 248 obese patients were enrolled in the study. Stone size was significantly higher in patients without stone-free status (p = 0.001). In patients who were stone-free and those with residual stones, the mean STONE score was 9.71 and 9.23 (p = 0.160), CROES was 172 and 129 (p = 0.001), and Guy's NSS was 1.67 and 2.75 (p = 0.001). Multivariate regression analysis identified the CROES and Guy's NSS were independent factors for PNL success in obese patients (p = 0.01 and p = 0.01, respectively). The CROES and Guy's NSS showed good accuracy with PNL success (AUC = 0.777 and AUC = 0.844, respectively). None of the three NSS systems were statically associated with a complication rate (p = 0.23 for STONE, p = 0.14 for CROES, and p = 0.51 for Guy's NSS). Our study demonstrated that CROES and Guy's NSS were independent predictors of stone-free rate following PNL in obese patients. Our study also revealed that three of the NSSs were not useful for predicting PNL complications in obese patients.

Implementation of minimally invasive percutaneous nephrolithotomy (MIP): comparison of the initial learning curve with the later on clinical routine in a tertiary centre

OBJECTIVE

We report on the comparison of clinical results of the early phase of implementation of minimally invasive PNL (MIP) in a mentor-based approach with the later on clinical routine in a tertiary centre.

PATIENTS AND METHODS

From January 2010 until January 2015 MIP was performed in 190 patients. Stone and patient characteristics were recorded in prospective manner. Perioperative complications were recorded within the Clavien-Classification. The first 120 consecutive patients undergoing MIP were evaluated and divided into three groups of 40 patients each. Mentor-based introduction of MIP was done within the first 40 patients (group A). Further patients were treated on routine clinical practice basis (group B and C). Treatment outcome was compared within the three groups.

RESULTS

The groups did not significantly differ with regard to patient characteristics, operation time and decline in haemoglobin. In the mentor-based series mean stone size was 21.7 ± 12.6 vs. 15.6 ± 7.9 and 16.1 ± 8.4 mm in group B and C (p = 0.033). Primary stone-free rates were 65, 87.5 and 87.5% for the three groups (p = 0.015). Stone-free rate was higher in smaller and simple stones. Overall, complication rate was 41.7% including 36.7% Clavien grade I and II complications.

CONCLUSIONS

MIP can be implemented safe and effectively with mentor-based approach. MIP has a high safety profile, which allows high safety and efficacy of MIP at the time of implementation.

Obesity and its implications on nononcological urological surgery

PURPOSE OF REVIEW

To review and summarize the current literature of the implications of obesity on nononcological urological surgery. We conducted a comprehensive search of the current literature with emphasis on the published literature in the last 18 months.

RECENT FINDINGS

Over time, obese patients have become a more common encounter in clinical practice. Obesity represents a considerable operative challenge and has been linked to a higher rate of postoperative complications. Data regarding surgery for incontinence are inconsistent. Nevertheless, the success rates in obese women are high, and complication rates are relatively low with comparable results to nonobese women. In renal surgery, percutaneous nephrolithotomy and minipercutaneous nephrolithotomy are feasible, well tolerated, and effective even in obese patients. However, certain precautions and availability of proper instruments are necessary.

SUMMARY

Although randomized clinical data are lacking and the results of many studies are inconsistent, evidence supports the feasibility and safety of different nononcological urological interventions in obese patients. Moreover, the success rates and the overall complication rates seem to be comparable to nonobese patients with some exceptions.

[S2k guidelines on diagnostics, therapy and metaphylaxis of urolithiasis (AWMF 043/025) : Compendium]

Every tenth German citizen will suffer from at least one urinary calculus during the lifetime. The diagnostics, treatment and follow-up treatment of urolithiasis are, therefore, part of the daily routine practice for all urologists in hospitals and private practices as well as in many other disciplines, such as general practitioners, internists, nephrologists and pediatricians. Although the diagnostics and therapy have experienced substantial alterations over the last 10 years, the possibilities of metabolic diagnostics and secondary prevention for patients at risk are, unfortunately and unjustly, in many places very poorly represented. The present S2k guidelines, which for the first time were established in an interdisciplinary consensus process, represent the current practical recommendations and, whenever possible, use tables and algorithms in order to facilitate easy reference in the routine daily work. Last but not least, this greatly simplifies the measures for metaphylaxis.

Percutaneous Nephrolithotomy in the Superobese: A Comparison of Outcomes Based on Body Mass Index

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is considered the gold standard for treatment of large renal calculi. Although several investigators have examined the feasibility and outcomes associated with PCNL in obese patients, these studies have been limited by small sample size, lack of a comparator group, or few patients at body mass index (BMI) extremes. We thus compared outcomes of superobese (BMI >50) patients undergoing PCNL vs both an "overweight" and "ideal" cohort.

METHODS

We used a prospectively maintained database to identify ideal (BMI 18.5-25), overweight (BMI 25.1-49.9), and superobese (BMI ≥50) patients who underwent PCNL. Our primary objective was to compare surgical outcomes between groups measured by the percent of patients who required secondary PCNL. We then compared complication rates, need for transfusion, and length of stay (LOS) using chi-square testing and ANOVA where appropriate.

RESULTS

A total of 1152 patients were identified of which 254 were classified as ideal, 840 as overweight, and 58 as superobese. The overweight cohort had a higher mean age and greater proportion of males, whereas staghorn stones were more common in the superobese group. Comorbid conditions were more commonly observed in the superobese cohort. Otherwise, the groups were similar. Surgical outcomes were comparable with 47.2%, 42.0%, and 38.0% of ideal, overweight, and superobese patients requiring secondary PCNL (p = 0.25) with no difference in complication rates, need for transfusion, or LOS.

CONCLUSION

PCNL can be effectively and safely performed in superobese patients with no difference in surgical outcomes or complications when compared to ideal or overweight patient cohorts.

Efficacy and safety of mini percutaneous nephrolithotomy in obese patients

Purpose

We aimed to evaluate the effect of obesity on surgical outcomes of mini percutaneous nephrolithotomy (Mini-PNL).

Methods

Hundred and eighty two Mini-PNL procedures were performed between May 2013 and January 2015 and their results were evaluated retrospectively. Patients were classified as non-obese (BMI, 18.5–30 kg/m²) and obese (≥30 kg/m²) groups. Obese and non-obese patients were compared according to pre-operative demographic values, intra-operative surgery techniques and post-operative results.

Results

BMI values of 133 patients were lower than 30 kg/m² while 49 patient’s BMI values were higher than 30 kg/m². There were no significant difference between operation time, fluoroscopy time, number of access and access sites when two groups were compared. No significant difference was found in total length of hospital stay, hemoglobin drop, and complication rates. Stone-free rates were 70.7 % in the non-obese and 71.4 % in the obese group (p = 0.9).

Conclusions

Mini-PNL procedure is a safe and effective treatment modality, which should be strongly considered for obese patients with appropriate sized stones.

Modified supine versus prone percutaneous nephrolithotomy: Surgical outcomes from a tertiary teaching hospital

Purpose

The traditional prone positioning of percutaneous nephrolithotomy (PCNL) is associated with various anesthetic and logistic difficulties. We aimed to compare the surgical outcomes of PCNLs performed using our modified supine position with those performed in the standard prone position.

Materials and Methods

A prospective group of 236 renal units (224 patients) undergoing PCNL were included in this 2 site study: 160 were performed in the modified supine position were compared with 76 undergoing PCNL in the prone position. The outcomes of radiation dose, radiation time, stone free rate, body mass index (BMI), stone size, operative time, length of stay (LOS), in hospital and complications were compared. Chi-square and t-tests were used.

Results

There were no significant differences in mean radiation time, radiation dose or stone size between the modified supine and prone groups. The supine group had a higher mean BMI (31 kg/m² vs. 28 kg/m², p=0.03), shorter mean surgical time (93 minutes vs. 123 minutes, p<0.001), shorter mean LOS (2 days vs. 3 days, p=0.005) and higher stone free rate (70% vs. 50%, p=0.005). There were no differences in septic or bleeding complications but the prone group had a higher rate of overall complications.

Conclusions

Modified supine PCNL has significantly lower operative time, shorter LOS and higher stone-free rate compared with prone in our series, while remaining a safe procedure.

The Effect of Obesity on Perioperative Outcomes Following Percutaneous Nephrolithotomy

OBJECTIVES

To test if obesity predisposes to higher rates of adverse outcomes after percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

Within the Nationwide Inpatient Sample (NIS), we identified patients treated with PCNL between 1998 and 2010 for kidney stones. We examined the temporal trends in PCNL use and charges among obese and nonobese patients. We then tested the effect of obesity on perioperative complications, transfusions, length of stay (LOS), and total hospital charges (THCs). LOS and THCs were defined as a continuous variable and were also dichotomized according to the 75th percentile into prolonged LOS (pLOS) and increased THCs (iTHCs). Then, multivariable models were fitted.

RESULTS

Overall, a weighted sample of 90,529 individuals treated with PCNL between 1998 and 2010 was examined. Of those patients, 9300 were obese (10.3%). The proportion of PCNLs performed in obese patients increased throughout the years from 7.4% to 16.7% (p < 0.001). Overall complication rates were 21.6% vs 22.0% (p = 0.3) and transfusion rates were 4.3% vs 4.0% (p = 0.1) for obese and nonobese patients, respectively. Obese patients had fewer genitourinary complications (13.4% vs 15.0%, p < 0.001), but had higher rates of sepsis (1.7% vs 1.3%, p = 0.009) as well as respiratory (3.0% vs 2.5%, p = 0.002) and vascular complications (0.3% vs 0.2%, p = 0.007). Conversely, pLOS (20.9% vs 18.8%, p < 0.001) and iTHCs (30.8% vs 24.4%, p < 0.001) were more frequently recorded in obese patients. In multivariable analyses, obesity was neither associated with higher rates of overall complications (odds ratio [OR], p = 0.3) nor with higher rates of transfusions (p = 0.3). However, obesity was associated with pLOS (OR: 1.21, p = 0.002) as well as iTHCs (OR: 1.17, p = 0.002).

CONCLUSIONS

PCNL in obese patients did not result in higher rates of individual complications or transfusions. However, it resulted in higher rates of pLOS and iTHCs.

The effect of abdominal fat parameters on percutaneous nephrolithotomy success

INTRODUCTION

Obesity has been suggested to lower the success of percutaneous nephrolithotomy (PCNL). However, the relationship between abdominal fat parameters, such as visceral and subcutaneous abdominal adipose tissue, and PCNL success remained unclear. In this study, we aimed to investigate the effect of abdominal fat parameters on PCNL success.

METHODS

A total of 150 patients who underwent PCNL were retrospectively enrolled in this study. Group 1 consisted of patients who had no residual stones or residual stone fragments <3 mm in diameter while group 2 included patients with residual stone fragments ≥3 mm. PCNL procedure was defined as successful if all stones were eliminated or if there were residual stone fragments <3 mm in diameter confirmed by non-contrast computed tomography (NCCT) performed postoperatively. Preoperative NCCT was used to determine abdominal fat parameters.

RESULTS

Group 1 consisted of 117 (78.0%) patients while group 2 included 33 (22.0%) patients. On univariate analysis, stone number, stone surface area (SSA), visceral fat area (VFA), abdominal circumference on computerized tomography (ACCT), and duration of procedure were found to be predictive factors affecting PCNL success. Logistic regression analysis revealed that ACCT and SSA were independent prognostic factors for PCNL success.

CONCLUSIONS

PCNL success was not affected by VFA, subcutaneous fat area (SFA) and body mass index (BMI) in our series. However, ACCT and SSA had negative associations with PCNL success. We conclude that both ACCT and SSA can be used as tools for predicting PCNL outcomes.

[Effect of the body mass index on outcomes of ureterorenoscopy for renal stones]

BACKGROUND

Purpose of this work is to compare the outcome of ureterorenoscopy (URS) with regard to stone-free rates (SFR) and complication rates (CR) in patients with different body mass index (BMI) scores for the treatment of kidney stones.

MATERIALS AND METHODS

A retrospective chart review of all patients with known BMI, who underwent URS for kidney stones between 2006 and 2012 at our institution, was performed (n = 556 patients). The SFR and CR of obese patients were compared to overweight and normal weight patients.

RESULTS

Mean age was 52.51 years and the average BMI 27.74 kg/m². Of the patients, 34.2 % had normal weight (22.59 ± 1.91 kg/m²), 39.6 % were overweight (27.30 ± 1.42 kg/m²), and 26.3 % were obese (35.09 ± 5.93 kg/m²). The mean ASA score differed significantly between normal weight (1.99 ± 0.57), overweight (2.03 ± 0.62), and obese (2.22 ± 0.63) patients (p ≤ 0.036). The mean stone size was 8.51 ± 6.84 mm and the mean number of stones per patient 1.9 ± 2.41, whereby the differences between groups was not significant. There were no differences between the groups regarding the use of preoperative (94.8 %) and postoperative ureteral stents (60.3 %), the Ho:YAG laser (33.6 %), the use of flexible (16.2 %) or semirigid/flexible URS (59.4 %), and the mean operative time (52.04 ± 34.55 min). There were no differences in the SFR for the upper (90 %), mid (94.7 %), and lower pole (90.2 %), multiple location (68.6 %) or the total SFR (86.3 %). Total SFR of 95.7, 88.4, and 73.7 % for urinary calculi < 5 mm, 5-9 mm, and ≥ 10 mm, respectively, were found and the differences between the patient groups was not significant. The CR was 10.4 % (differences between the patient groups not significant).

CONCLUSION

URS is an appropriate treatment for renal stones with high SFR and low CR regardless of patient's BMI.

Ultrasound Guidance to Assist Percutaneous Nephrolithotomy Reduces Radiation Exposure in Obese Patients

OBJECTIVE

To evaluate the impact of body mass index (BMI) on perioperative outcomes and radiation exposure for ultrasound (US)-guided percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

Data were prospectively collected for consecutive patients who underwent PCNL at the University of California, San Francisco, from July 2013 to November 2015. Patients were divided into 3 groups according to their BMI: <25 (normal weight), 25-29.9 (overweight), and >30 (obese) kg/m². Perioperative outcomes were compared between patients who underwent US-guided vs fluoroscopy-guided PCNL.

RESULTS

One hundred thirty-five patients were enrolled; 93 cases were performed under US and 42 under fluoroscopic guidance. US successfully guided renal access in 76.9% of normal weight, 79.0% of overweight, and 45.7% of obese patients (P < .05). Mean fluoroscopic screening time and radiation exposure dose were reduced for US compared to fluoroscopy cases across all BMI categories (P < .05). As BMI increased, radiation exposure dose rose disproportionately faster compared to screening time (P < .001). No significant differences among the BMI groups were found with regard to complication rate, hospital stay, and stone-free status.

CONCLUSION

US-guided PCNL may be more difficult in obese patients, but with its use, the overweight and obese experience the largest absolute reduction in radiation exposure. Because these patients are inherently at greater risk for radiation exposure compared to normal weight patients, they may benefit the most from adoption of US for PCNL.

Effect of body mass index on operative time, hospital stay, stone clearance, postoperative complications, and postoperative analgesic requirement in patients undergoing percutaneous nephrolithotomy

OBJECTIVE

To compare the effect of body mass index (BMI) on operative time, hospital stay, stone clearance, postoperative complications, and postoperative analgesic requirement in patients undergoing percutaneous nephrolithotomy (PCNL) by comparing three BMI groups.

MATERIAL AND METHODS

This is a retrospective analysis of 129 patients who underwent PCNL from January 2010 to August 2013. All the patients underwent PCNL by a standard technique. The patients were divided into three groups: patients having a BMI ≤24 kg/m(2) were included in the normal group, those having a BMI of 24.1-30.0 kg/m(2) were included in the overweight group, and those having a BMI >30 kg/m(2) were included in the obese group. Three groups were compared for operative time, hospital stay, stone clearance, postoperative complications, and postoperative analgesic requirement.

RESULTS

A total of 129 patients including 44 females and 85 males were included with a mean age of 45.00±1.44 years. The mean age in the normal group was 43.29±1.69 years, 47.08±1.29 years in the overweight group, and 43.61±1.25 years in the obese group. The mean stone size in the normal group was 25.46±8.92 mm, 28.01±8.40 mm in the overweight group, and 26.84±7.41 mm in the obese group. Our results showed no statistically significant difference with respect to mean operative time, mean hospital stay, and stone clearance in the normal, obese, and overweight patients undergoing PCNL. Postoperative complications and analgesia requirement were also similar in all the three groups.

CONCLUSION

There was no effect of BMI on operative time, hospital stay, stone clearance, postoperative complications, and postoperative analgesic requirement in patients undergoing PCNL. PCNL is a safe and effective procedure for the removal of renal stones in obese patients.

Effectiveness of retrograde intrarenal stone surgery in obese patients

BACKGROUND

A number of comorbid health problems can be found in obese patients. These problems increase the surgical risk in obese patients.

AIMS

To determine the effectiveness of retrograde intrarenal surgery for renal stone treatment in obese patients.

METHODS

We retrospectively reviewed the data of 106 patients who had retrograde intrarenal surgery with the diagnosis of renal stone in our clinic. The patients were divided into three groups regarding their body mass indexes: ≥30 kg/m² being obese (group 1), 25-29.9 kg/m² being overweight (group 2), and <25 kg/m² being normal weight (group 3). The patients were compared for age, gender, and stone characteristics. In addition, the duration of surgery, stone-free rate (SFR), complication rate, and the duration of the hospital stay were compared among the groups.

RESULTS

Twenty eight patients were obese (group 1), 49 patients were overweight (group 2), and 29 patients were normal weight (group 3). The mean ages of groups 1, 2 and 3 were 51.5 (29-84), 47 (30-76) and 35 (19-84) years, respectively (p = 0.001). SFR was 85.7 % in group 1, 89.8 % in group 2, and 75.9 % in group 3 (p = 0.24). The duration of surgery was similar in groups 1, 2, and 3, being 45.5 (25-95), 50 (30-120), and 45.5 (10-100) min, respectively (p = 0.23). None of the patients had major complications.

CONCLUSIONS

Our results indicate that retrograde intrarenal surgery is a safe and efficient surgical method for renal stone treatment in obese and overweight patients.