[Flexible ureterorenoscopy in obese patients: results from a large monocenter cohort]

Urinary tract infection after flexible ureterorenoscopy for urolithiasis in patients with positive treated preoperative urinalysis

Prevalence of kidney stones is increasing worldwide, flexible ureterorenoscopy (f-URS) is the most common surgical treatment. Postoperative urinary tract infection (PUTI) is the primary complication. Some risk factors are classically associated with PUTI, especially preoperative positive urinalysis (POPU). We aimed to identify risk factors for PUTI after f-URS for urolithiasis in patients with treated POPU, and to identify the different pre and postoperative pathogens. Retrospective, single-center study of all f-URS for urolithiasis between January 2004 and December 2020. Procedures with treated POPU were categorized as PUTI or no PUTI (NPUTI). We examined demographics, preoperative, perioperative and postoperative characteristics in each group. Among 1934 procedures analyzed, 401 (20.7%) had POPU; these were categorized into NPUTI (n = 352, 87.8%) and PUTI (n = 49, 12.2%). By univariate analysis, only preoperative stenting duration (76.3 in NPUTI group vs 107.7 days in PUTI group, p = 0.001) was significantly associated with a higher risk of PUTI in univariate analysis. Germ distribution was similar in both groups. We compared pre- and postoperative microbiological data for interventions with PUTI, and found that only 8.7% of pathogens were identical between pre and postoperative urinalysis. Our study shows that the rate of PUTI is higher for patients with a POPU and that preoperative stent duration is the sole risk factor in patients with POPU. The low concordance rate (8.7%) between POPU and post-operative pathogens highlights the need for further research on obtaining sterile preoperative urinalysis, or performing intraoperative culture (urines, stent or stone), to treat PUTI early with an adapted antibiotic therapy.

Percutaneous Nephrolithotripsy in Morbidly Obese Patient: A Case Report

A 50-year old male patient with morbid obesity was admitted for removal of large staghorn calculi and multiple small stones in the left kidney. The patient was managed by Percutaneous Nephrolithotomy (PCNL). Surgery was carried out in prone position and Alken's metal dilators were used for tract dilation. Alken dilators were inserted without any challenges, and the procedure was completed in a shorter span of time than anticipated with total operative time of 2 hours, including the change of positioning from lithotomy to prone. No intra-operative or post-operative complications were encountered. The patient has been followed up for 6 months post-operatively, without any complications or any evidence of stone recurrence.

Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

OBJECTIVE

To evaluate four predictive scores for stone-free rate (SFR) after flexible ureterorenoscopy (f-URS) with holmium-YAG laser fragmentation of renal and ureteral lithiasis.

METHODS

We carried out a retrospective analysis of 800 f-URS procedures performed in our institution between January 2009 and December 2016. For each procedure, a single surgeon calculated the following scores: S.T.O.N.E score; Resorlu Unsal Stone Score (RUSS); modified Seoul National University Renal Complexity (S-ReSC) score; and Ito's score.

RESULTS

Overall SFR was 74.1%. Univariate analysis demonstrated that stone size (p<0.0001), stone volume (p<0.0001), stone number (p = 0.004), narrow lower pole infundibulopelvic angle (IPA) (p = 0.003) and lower pole location + IPA <45° (p = 0.011) were significantly associated with SFR. All scores differed between the stone-free and non-stone-free groups. Area under the curve of the receiving operator characteristics curve was calculated for each score: 0.617 [95%CI: 0.575-0.660] for the S.T.O.N.E score; 0.644 [95%CI: 0.609-0.680] for the RUSS; 0.651 [95%CI: 0.606-0.697] for the S-ReSC score; and 0.735 [95%CI: 0.692-0.777] for Ito's nomogram.

CONCLUSION

All four scores were predictive of SFR after f-URS. Ito's score was the most sensitive. However, the performance of all scores in this analysis was lower than in developmental studies.

[Flexible ureterorenoscopy vs percutaneous nephrolithotomy for renal stone management: Retrospective study]

PURPOSE

The aim of this study was to evaluate the efficacy and tolerance of renal stone fragmentation by flexible ureterorenoscopy (URS), compared to percutaneous nephrolithotomy (PCNL).

MATERIAL AND METHODS

Patients treated between 1998 and 2010 by URS and PCNL for intrarenal stone were reviewed. Patients' and stones' characteristics were analyzed. The preoperative parameters were reported as well as the procedure's efficiency and its complications. Success was defined by the absence of residual lithiasis visualized on renal imaging at 6 months of follow-up.

RESULTS

Among 531 patients included, there were 159 PCNL and 372 URS. The mean duration of hospitalization after PCNL was 8±4.6 days and 3±1.7 days after URS. The mean stones' size was higher in the PCNL group (19.9±7.5mm) than for the URS group (9.7±5.6mm; P<0.0001). The stone-free rate was significantly better in the PCNL group for stones measuring between 10 and 20mm (P<0.0001) and for stones of more than 20mm (P=0.017). Postoperative complications were significantly more frequent (27 %) and more severe (8.8 % vs Clavien III and IV) in the PCNL, than in the URS group, respectively (P=0.0001).

CONCLUSION

PCNL is a successful technique for renal stone fragmentation. However, URS seemed more tolerated despite a lower stone-free rate.

LEVEL OF EVIDENCE

4.