The Impact of Endourological Experience on Flexible Ureteroscopy Outcomes and Performance at Different Levels of Expertise: Retrospective Multifactorial Analysis

The Role of 12/14F Ureteral Access Sheath in Flexible Ureteroscopy for Moderate Nephrolithiasis

INTRODUCTION

The aim was a retrospective analysis of 12/14F ureteral access sheath (UAS) usage on perioperative outcomes in patients with moderate nephrolithiasis (MN). MN was defined as a maximum of two unilateral kidney stones with a maximum stone diameter of 6-10 mm.

MATERIAL AND METHODS

We conducted a monocentric retrospective univariate and multivariate analysis of flexible ureteroscopies (fURS) performed for MN between 01/2014 and 12/2018.

RESULTS

A total of 402 fURS were performed in patients with urolithiasis; 112 MN cases underwent further analysis. UAS was successfully applied in 33 MN cases [33/112 (29.46%)]. UAS was inserted regardless of the maximum kidney stone diameter and the presence of multiple kidney stones (p > 0.05). Univariate analysis revealed a prolonged median operation time (UAS: 94 min, non-UAS: 74 min, p = 0.04) and median fluoroscopy time (UAS: 75 s, non-UAS: 57.5 s, p = 0.04) in the UAS cohort. These differences were not confirmed on multivariate logistic regression.UAS was not associated with better stone-free rates in either the univariate or multivariate analysis (UAS: 26/33, non-UAS: 61/79, p = 1.0) nor with the occurrence of Clavien-Dindo ≥2 complications (UAS: 3/33, non-UAS: 9/79, p = 0.98) or median length of hospital stay (UAS: 2 days, non-UAS: 2 days, p = 0.169).

CONCLUSION

We identified no statistical benefits from the usage of 12/14F UAS for MN. As no relevant UAS-associated complications were documented, both strategies (with and without UAS) are feasible.

Learning curve in flexible ureteroscopy for renal stones: A propensity score-matched study

OBJECTIVE

To assess the learning curve and evaluate the impact of surgical experience related to the outcomes of flexible ureteroscopy (fURS) for upper urinary tract stones.

METHOD

We evaluated retrospectively lithiasis fURS performed in our institution between January 2004 and December 2020. Patients were divided into two groups by the number of procedures performed by surgeon. Group 1 (G1) included the first 50 procedures, and group 2 (G2) the next cases. These groups were matched on baseline characteristics by a propensity score. Stones free rate (SFR) and complication rate (CR) were compared. Learning curves were realized using logistic curve with 95% confidence interval.

RESULTS

After criteria exclusion and propensity score matching, 1548 procedures were analyzed (1:1, G1 and G2, n=774 procedures). A total of 29 surgeons were evaluated. The overall SFR was 68.4% without statistical difference between the two groups (G1=67.9% vs. G2=68.8%, P=0.72). The surgeon's experience was not associated with SFR (OR=1.15, 95% CI: 0.90-1.47), except in subgroup stones>2cm (OR=2.89, 95% CI: 1.29-6.46). The overall CR was 12.5%, mainly Clavien-Dindo grade I-II complications (96.2%). Surgical experience was not associated with CR (OR=1.06, 95% CI: 0.77-1.45). The overall logistic curves for probability of stone clearance and complication tended to be a flat slope.

CONCLUSION

Impact of surgical experience on fURS for UUTS was not associated with SFR and CR. However, for stones larger than 2cm, surgeon's experience tended to be associated with SFR, but without impact on overall complications.

LEVEL OF EVIDENCE: 3

The dilemma of 12/14F ureteral access sheath (UAS) usage: a case control study

BACKGROUND

The insertion of a ureteral access sheath (UAS) is a frequent procedure during flexible ureteroscopy (fURS) to facilitate kidney stone treatment. The aim of this study was to investigate the influence of 12/14 French (F) UAS on fURS outcomes.

METHODS

We performed a retrospective monocentric analysis of fURS procedures conducted at the Department of Urology (University Hospital Schleswig-Holstein, Lübeck, Germany) for kidney stone treatment via lithotripsy or basket stone retrieval between September 2013 and June 2017. Uni- and multivariate analyses were done with the help of RStudio (Version 1.0.136) software.

RESULTS

In total, 283 consecutive fURS were analyzed. UAS was applied in 98 cases (34.63%). The insertion of UAS was preferred in cases with multiple kidney stones and larger median maximal stone diameter (p < 0.05). UAS usage correlated with elevated radiation exposure in seconds (94 vs. 61; p < 0.0001), prolonged operation time in minutes (99 vs. 66, p < 0.0001), length of hospital stay over 48 h (LOS, 22.49% vs. 10.81%; p = 0.015), more frequent postoperative systemic inflammatory response syndrome (SIRS, 13.27% vs. 4.32%; p = 0.013) and lower postoperative stone-free rates (60.20% vs. 78.92%; p = 0.0013). Moreover, we conducted uni- and multivariate subgroup analysis for cases with multiple kidney stones (≥ 2) and comparable stone burden; UAS was inserted in 48.3% of these cases (71/147). On multivariate logistic regression, UAS insertion was statistically associated with prolonged operation time in minutes (101 vs. 77; p = 0.004). No statistical differences regarding radiation exposure, stone-free rates, postoperative SIRS rates or LOS were noted between UAS and non-UAS patients with multiple kidney stones of similar size (p > 0.05).

CONCLUSIONS

12/14F UAS does not seem to improve overall outcomes in fURS for kidney stones. In patients with multiple kidney stones it may be associated with elevated operation time without a clear benefit in terms of improved stone-free status or reduced perioperative complication rate. Further prospective randomized studies to specify the indications for UAS usage are urgently needed.

Flexible Ureterorenoscopy under Spinal Anesthesia: Focus on Technique, Results, Complications, and Patients' Satisfaction from a Large Series

INTRODUCTION

Although spinal anesthesia (SA) may reduce postoperative morbidity, most urologists perform flexible ureterorenoscopy (fURS) under general anesthesia (GA). The objective of our study is to provide technical details, results, complications, and patients' satisfaction with fURS performed under exclusive SA.

METHODS

We analyzed all consecutive fURS performed under SA to treat renal stones from March 2011 to February 2017. Details of technique, operative time, outcomes, need for further treatments, complications, and patients' satisfaction were evaluated.

RESULTS

Two hundred thirty-four fURS under SA were considered. SA was performed through L2-L3 vertebral interspace in 64.1%. Patients were discharged the same day of surgery. Mean stone burden was 13.5 ± 6.6 mm and mean operative time 76.9 ± 34.6 min. Single-procedure SFR was 69.7%. Further treatments were performed in 22.8%. 96.6% had no anesthesia-related complications. No Clavien-Dindo grade ≥ IIIb complications were noticed. 99.6% of patients were satisfied with SA. No cases of conversion from SA to GA occurred.

CONCLUSION

fURS can be performed safely and efficiently under SA, taking into account a few details of the technique. Patients' satisfaction with SA is very high, and complications are rare. Although SA is usually adopted in unfit patients for GA, it may be considered as a viable alternative in fit patients.

Efficiency and Clinical Outcomes of Moses Technology with Flexible Ureteroscopic Laser Lithotripsy for Treatment of Renal Calculus

OBJECTIVE

The aim of the study was to compare the efficiency and clinical outcomes of Moses contact mode (MCM) and regular dusting mode (RDM) during flexible ureteroscopic lithotripsy (FURL) for treatment of renal calculus.

METHODS

This retrospective analysis examined 216 patients with renal calculus who underwent FURL with MCM or RDM between March 2015 and January 2020. Stone characteristics, including size, volume, and density, were collected. Laser parameters, including laser type, laser working time, laser pause time, and foot-pedal use, were automatically recorded by the lithotripter work panel. The percentages of laser working time and laser pause time, stone fragmentation efficiency (SFE; volume/laser working time), postoperative complications, including fever and acute renal failure (ARF), stone-free rate (SFR), and the need for auxiliary procedures were determined.

RESULTS

There were no significant differences in preoperative demographic and stone characteristics between the MCM group and the RDM group. The MCM group had a shorter laser working time (4.99 ± 1.06 vs. 5.94 ± 0.96 min, p < 0.001) and a greater SFE (137.86 [163.78-114.38] versus 114.94 [132.06-101.34] mm3/min, p < 0.001), which shortened the overall operative time (18.39 ± 5.13 vs. 21.17 ± 6.78 min, p = 0.001). There were no differences in postoperative complications, including fever and ARF, SFR (86.8 vs. 85.3%, p = 0.743), and auxiliary procedures between the 2 groups.

CONCLUSIONS

Using Moses laser technology with FURL significantly reduced laser working time and increased SFE, which shortened overall operative time. Urologists should consider this new instrument for the clinical management of renal calculus.

Validation of a Bench-Top Training Model for Retrograde Intrarenal Surgery

OBJECTIVE

To validate the in-house built Styrofoam box bench-top training model for retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

This study was performed in the setting of a half-day RIRS course. During the course, participants performed RIRS on a locally built bench-top model. We recruited 26 participants, comprising 20 trainees and 6 experts. Trainees and experts were asked to fill a self-administered questionnaire assessing various components of RIRS to assess the face and content validity. For construct validity, experts using Objective Structured Assessment of Technical Skills (OSATS) rated trainees and the mean OSATS score of junior versus senior residents was compared.

RESULTS

As per trainees, the model was 86% (4.3/5) realistic, which was backed by experts who found this model to be 87.6% (4.38/5) realistic. The overall face validity of the model was 86.4% (4.32/5). The overall content validity of this model was 83.4% (4.17/5). Majority of the participants thought that this tool is useful for learning technique (4.38 ± 0.49) and safe-conduct (4.31 ± 0.73) of the procedure. The trainees concurred that the skills acquired are transferable to the operating room (4.23 ± 0.76). However, the construct validity by comparing mean OSATS score of junior versus senior residents was 19.5 ± 3.5 and 23 ± 4.5. A p value of 0.11 could not be established.

CONCLUSION

This study has demonstrated the face, content, and construct validity of the bench-top training model for RIRS. Further evaluation is necessary to compare its effectiveness against other available models to demonstrate concurrent validity.