Definition and Unfavorable Risk Factors of Trifecta in Mini-Percutaneous Nephrolithotomy

Trifecta in flexible ureteroscopy for treatment of renal and upper ureteral calculi: A multicenter study

Purpose

To determine predictors for missing trifecta in patients who underwent flexible ureteroscopy (FURS) for treatment of renal and upper ureteric calculi.

Patients and Methods

The data of adult patients with renal or upper ureteral stones who underwent FURS from June 2021 through December 2022 were retrospectively reviewed. Stone-free status (no residual stones > 3 mm) was evaluated after 3 months with non-contrast CT. Modified Clavien classification was used to grade complications. A stone-free status after a single intervention of FURS without complications was defined as trifecta. Patients were divided into two groups (trifecta and non-trifecta). Risk factors for missing trifecta were compared between both groups using univariate and multivariate analyses.

Results

Three hundred twenty-three patients with mean age 48.9 ± 13 years and mean stone length 16 ± 5.9 mm were included. The trifecta criteria were applicable for 250 patients (71%). On multivariate analysis, risk factors for missing trifecta were stone multiplicity (OR: 3.326, 95%CI: 1.933-5.725) and non-experienced surgeons (OR: 1.819, 95%CI: 1.027-3.220).

Conclusions

Multiple stones and performance of FURS by non-experienced surgeons are the independent risk factors for missing trifecta of FURS.

Antegrade flexible ureteroscopy-assisted percutaneous nephrolithotomy for staghorn calculi: a prospective randomized controlled study

The aim is to compare the efficacy and safety between single percutaneous nephrolithotomy (sPNL) and antegrade flexible ureteroscopy-assisted percutaneous nephrolithotomy (aPNL) for the treatment of staghorn calculi. A prospective randomized controlled study was conducted at the Second Hospital of Tianjin Medical University. A total of 160 eligible patients were included, with 81 in the sPNL group and 79 in the aPNL group. The study first compared the overall differences between sPNL and aPNL. Then, the patients were divided into two subgroups: Group 1 (with less than 5 stone branches) and Group 2 (with 5 or more stone branches), and the differences between the two subgroups were further analyzed. The results showed that aPNL had a higher stone-free rate (SFR) and required fewer percutaneous tracts, with a shorter operation time compared to sPNL (P < 0.05). Moreover, aPNL significantly reduced the need for staged surgery, particularly in patients with 5 or more stone branches. Moreover, there were no significant differences in the changes of hemoglobin levels and the need for blood transfusions between the sPNL and aPNL groups, and the incidence of multiple tracts was lower in the aPNL group. The two groups showed comparable rates of perioperative complications. We concluded that aPNL resulted in a higher SFR for staghorn calculi, and required fewer multiple percutaneous tracts, reduced the need for staged surgery, and had a shorter operative time than PNL alone, especially for patients with 5 or more stone branches. Furthermore, aPNL did not increase the incidence of surgical complications.

Vacuum-assisted access sheath in supine mini-percutaneous nephrolithotomy (mini-PCNL)

INTRODUCTION

The vacuum-assisted access sheath is a new device for the treatment of kidney stones with percutaneous nephrolithotomy (PCNL).

OBJECTIVE

Our aim was to compare the stone-free rate (SFR) and complications between standard mini percutaneous nephrolithotomy (Mini-PCNL) and vacuum-assisted PCNL (Va-PCNL).

METHODS

Retrospective study of patients undergoing Mini-PCNL and Va-PCNL from January 2018 to June 2022. Va-PCNL was performed with a disposable sheath (ClearPetra®) with continuous high-flow irrigation and vacuum fluid dynamics for easier stone fragment removal. Baseline patient characteristics, surgical outcomes, perioperative and postoperative data were collected. We compared SFR and complications.

RESULTS

A total of 136 patients were identified, 57 (41,9%) underwent Va-PCNL and 79 (58,15%) Mini-PCNL. Mean operative time was significantly shorter in the Va-PCNL group (95 min.) than in Mini-PCNL (146 min; P = ,001) group. The tubeless technique was performed more frequently in Va-PCNL group (61,4% vs. 34,2%; P = ,002). We did not observe any differences in postoperative complications. The mean hospital stay was significantly lower in Va-PCNL with 1,7 ± 1,9 days per patient compared with 2,7 ± 1,5 days in the Mini-PCNL group (P = ,001). There were no differences in SFR at 3 months between Va-PCNL (71,9%) and Mini-PCNL (71,8%; P =v ,848).

CONCLUSION

Patients treated with Va-PCNL had comparable results to Mini-PCNL, showing equal SFR with similar infectious complications rates. Potential benefits of Va-PCNL include shorter operative time and postoperative stay.

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.

Validation of the Trifecta Scoring Metric in Vacuum-Assisted Mini-Percutaneous Nephrolithotomy: A Single-Center Experience

Background: Scoring metrics to assess and compare outcomes of percutaneous nephrolithotomy (PCNL) are needed. We aim to evaluate prevalence and predictors of trifecta in a cohort of patients treated with vacuum-assisted mini-percutaneous nephrolithotomy (vmPCNL) for kidney stones. Methods: Data from 287 participants who underwent vmPCNL were analysed. Patients’ and stones’ characteristics as well as operative data were collected. Stone-free was defined as no residual stones. The modified Clavien classification was used to score postoperative complications. Trifecta was defined as stone-free status without complications after a single session and no auxiliary procedures. Descriptive statistics and logistic regression models tested the association between predictors and trifecta outcome. Results: After vmPCNL, 219 (76.3%) patients were stone-free, and 81 (28.2%) had postoperative complications (any Clavien). Of 287, 170 (59.2%) patients achieved trifecta criteria. Patients who achieved trifecta status had smaller stone volume (p < 0.001), a higher rate of single stones (p < 0.001), shorter operative time (p < 0.01), and a higher rate of single percutaneous tract (p < 0.01) than −trifecta patients. Trifecta status decreased with the number of calyces involved, being 77.1%, 18.8%, and 4.1% in patients with 1, 2, or 3 calyces with stones, respectively (p < 0.001). Multivariable logistic regression analysis showed that stone volume (OR 1.1, p = 0.02) and multiple calyces being involved (OR 2.8 and OR 4.3 for two- and three-calyceal groups, respectively, all p < 0.01) were independent unfavourable risk factors for trifecta after accounting for age, BMI, gender, operative time, and number of access tracts. Conclusions: Trifecta status was achieved in 6 out of 10 patients after vmPCNL. Stone distribution in multiple calyceal groups and stone volume were independent unfavourable risk factors for trifecta.