Retrograde intrarenal surgery of renal stones: a critical multi-aspect evaluation of the outcomes by the Turkish Academy of Urology Prospective Study Group (ACUP Study)

Comparison of flexible vacuum-assisted ureteral access sheath versus conventional sheath combined with single-use flexible ureteroscope in the treatment of renal calculi

To evaluate the safety and efficacy of the flexible vacuum-assisted ureteral access sheath combined with the single-use flexible ureteroscopy in the treatment of renal calculi. We prospectively analyzed the patients treated with single-use flexible ureteroscopy from January 2023 to December 2023, among which 113 cases were treated with flexible vacuum-assisted ureteral access sheath (FV-UAS group) and 113 cases were treated with conventional sheath (conventional sheath group). Patient data ofthe two groups were collected and recorded before and after operation. No significant differences were observed between the two groups regarding demographics and pre-operative clinical characteristics. The duration of the operation was significantly longer in the FV-UAS group (79.5 ± 6.8 min) compared to the conventional UAS group (65.2 ± 7.3 min). However, the stone free rate (SFR) at one day and one month post-operation in the FV-UAS group was 85.6% and 98.2%, respectively, significantly higher than that in the conventional UAS group (72.6%, 90.3%). Complications such as infection and urosepsis were more common in conventional UAS group. Notably, hospitalization costs were lower in the FV-UAS group. Flexible vacuum-assisted ureteral access sheath combined with flexible single-use ureteroscope is a feasible and effective method for treating renal calculi. It offers higher SFR and lower rate of infectious complications.

Assessment of Intrarenal Pressure through Dilatation State of the Renal Collecting System

INTRODUCTION

The aim of the study was to explore the relationship between the dilation states of the renal collecting system in flexible ureteroscopy (f-URS) view and intrarenal pressure (IRP).

METHODS

Fifteen porcine kidneys were randomly selected and numbered 1 through 15. Pressure transducers were inserted into the renal calyx via puncture and adjusted to a zero position. The distal end of the f-URS probe was placed within the renal pelvis. Perfusion rates of 50 mL/min, 80 mL/min, and 100 mL/min were utilized. We observed the relationship between the dilation state of the renal collecting system and changes in IRP. The state of complete dilation was defined as an unchanging spatial morphology of the renal collecting system as visualized during f-URS.

RESULTS

With irrigation rates of 50 mL/min, 80 mL/min, and 100 mL/min, IRP values at the moment of complete dilation of the renal collecting system ranged from 16 to 18 cm H2O, 16-19 cm H2O, and 16-19 cm H2O, respectively. Maximum IRPs ranged from 47 to 49 cm H2O, 82-85 cm H2O, and 97-100 cm H2O, respectively. Prior to complete dilation of the renal collecting system, IRP consistently remained below 20 cm H2O. However, following full dilation of the renal collecting system, IRP rose rapidly and rapidly surpassed 20 cm H2O. Despite sustained elevations in IRP following full dilation, no significant alterations in the renal collecting system dilated morphological were observed with f-URS.

CONCLUSIONS

In vitro experiments indicate that when the renal collecting system is not fully dilated, the IRP is consistently less than 20 cm H2O. Evaluation of IRP being within a safe range can be determined by assessing the dilation status of the renal collecting system.

Microchannel percutaneous nephrolithotomy versus flexible ureteroscopic lithotripsy for the treatment of 1-2 cm high hardness single upper ureteral stones: a propensity score-matched study

The objective of this study was to compare the clinical efficacy and safety of microchannel percutaneous nephrolithotripsy (MPCNL) with flexible ureteroscopic lithotripsy (FURL) in the treatment of single upper ureteral stones with a diameter of 1-2 cm and high hardness. This study retrospectively analyzed 89 patients diagnosed with a single upper ureteral stone with a 1-2 cm diameter and a computed tomography value > 1000 Hounsfield units. A propensity score matching system matched this study with factors to minimize the effect of baseline differences between patients. Ultimately, 29 patients in each of the two groups were successfully matched. The stone-free rate was marginally higher in the MPCNL group than in the FURL group (93.10% vs. 86.21%), although the difference did not reach statistical significance (P = 0.666). Furthermore, the mean operative time in the MPCNL group, although slightly longer than that in the FURL group, did not demonstrate a statistically significant difference (P = 0.833). However, patients in the MPCNL group exhibited a significantly more substantial decrease in hemoglobin than those in the FURL group (P < 0.001) and a substantially more extended postoperative hospital stay (P < 0.001). Regarding perioperative complications, the incidence of moderate pain was higher in the MPCNL group than in the FURL group (P = 0.037). The difference in overall complication rates between the two groups did not reach statistical significance (P = 0.108). MPCNL and FURL are efficacious surgical procedures for treating single upper ureteral stones with a 1-2 cm diameter and high hardness.

Is fluoroscopy-free single-use flexible ureteroscopy a feasible treatment for kidney stones with abnormal renal anatomy?

Objective

This study aimed to evaluate the feasibility of the fluoroscopy-free single-use flexible ureteroscopy procedure in the treatment of kidney stones with abnormal renal anatomy compared to normal renal anatomy.

Methods

Forty patients with abnormal (Group A) and 80 patients with normal (Group B) renal anatomy who had 10-20 mm renal stones were included. They were treated with LithoVue single-use flexible ureteroscopy (Boston Scientific, Marlborough, MA, USA) after ureteric dilatation by two different size semi-rigid ureteroscopes. This technique was chosen as the aim was to exclude any ureteric pathology (e.g., stone or stricture), confirm the placement of a safe guidewire, avoid balloon dilatation of the ureter, and achieve safe insertion of a 12 Fr, 35/45 cm ureteric access sheath with optical and tactile sign and without fluoroscopy image for guidance.

Results

The mean ages were 43 years and 45 years in Group A and Group B, respectively. The mean stone burden was 14.62 (standard deviation: 5.35) mm3 and 14.79 (standard deviation: 4.58) mm3 in Group A and Group B, respectively. There is no significant difference between both groups according to the mean operative time, hospital stay, or stone-free rate. The stone-free rate was about 93% in both groups when the stone size was between 10 mm and 15 mm, and less than 54% when the stone size was more than 15 mm to 20 mm. In the majority of cases (80.0% in Group A and 92.5% in Group B), we completed the procedure without fluoroscopy. The perioperative complication rates were comparable in the two groups.

Conclusion

Fluoroscopy-free single-use flexible ureteroscopy, when performed by expert urologists, is a feasible treatment for pre-stented patients with kidney calculi of ≤15 mm with abnormal renal anatomy.

RIRS with FV-UAS vs. MPCNL for 2-3-cm upper urinary tract stones: a prospective study

To observe the efficacy and safety of retrograde intrarenal surgery (RIRS) combined with flexible vacuum-assisted ureteral access sheath (FV-UAS) and minimally invasive percutaneous nephrolithotomy (MPCNL) in patients with 2-3 cm upper urinary tract stones. A total of 160 patients with 2-3 cm upper urinary tract stones were prospectively randomized into 2 groups-80 in the FV-UAS group and 80 cases as control in the MPCNL group. The stone-free rates (SFRs) at different times (postoperative 1st day and 4th week) were considered as the primary outcome of the study. The secondary end points were operative time, hemoglobin decrease, postoperative hospital stay, and operation-related complications. There was no obvious difference between the two groups in patient's demographics and preoperative clinical characteristics (all P > 0.05). Postoperative data showed that mean decrease in hemoglobin level was less in FV-UAS group than that in MPCNL group (5.3 vs. 10.8 g/L, P < 0.001). Postoperative hospital stay in FV-UAS group was more shorten than that in MPCNL group (2.7 vs. 4.9 days, P < 0.001). There was no statistical significance between the two groups in SFRs during postoperative 1st day and 4th week (both P > 0.05). However, in terms of the rates of bleeding and pain, MPCNL group were both significantly higher than FV-UAS group (6.2 vs. 0.0%, P = 0.023; 16.2 vs. 2.5%, P = 0.003; respectively). Our study showed that RIRS with FV-UAS, a new partnership to treat 2-3 cm upper urinary tract stones, was satisfying as it achieved a high SFR rate and a low rate of complications. This method was safe and reproducible in clinical practice.

Comparison of traditional and novel tip-flexible suctioning ureteral access sheath combined with flexible ureteroscope to treat unilateral renal calculi

OBJECTIVES

To compare the safety and efficacy of novel tip-flexible suctioning ureteral access sheath (NTFS-UAS) and traditional ureteral access sheath (T-UAS) combined with flexible ureteroscope for treating unilateral renal calculi.

MATERIALS AND METHODS

The clinical data of 214 patients with unilateral renal calculi treated by NTFS-UAS (n = 102) and T-UAS (n = 112) combined with flexible ureteroscope from August 2021 to April 2022 were analyzed retrospectively. Demographic characteristics, stone-related parameters, operative time, stone-free rates (SFR), hospitalization time and complication rate (CR) were analyzed.

RESULT

No significant difference was observed between the two groups in terms of demographic characteristics, stone-related parameters, intraoperative CR, and hospitalization time. The operative time of NTFS-UAS group was significantly shorter than T-UAS group (55.25 ± 11.42 min vs. 59.36 ± 15.59 min; P = 0.028). The NTFS-UAS group obtained significantly higher SFR on 1 day postoperatively (86.3% vs. 75.0%; P = 0.038), and higher SFR on 30 days postoperatively than T-UAS group (91.2% vs. 81.3%; P = 0.037). The hemoglobin loss of NTFS-UAS group (- 0.54 ± 0.69 g/dl) was significantly lower than T-UAS group (- 0.83 ± 0.66 g/dl; P = 0.002). There was a significantly lower incidence of overall CR (11.8% vs. 22.3%; P = 0.041), and infectious CR (8.8% vs. 18.8%; P = 0.037) in the NTFS-UAS group.

CONCLUSION

Compared to T-UAS combined with flexible ureteroscope for treating unilateral renal calculi, NTFS-UAS had superiority in higher SFR on 1 day and 30 days postoperatively. Shorter operation time, lower hemoglobin loss, lower incidences of overall and infectious CR were observed in NTFS-UAS group.

REGISTRATION NUMBER AND DATE

ChiCTR2300070210; April 5, 2023.

Comparative efficacy between retrograde intrarenal surgery with vacuum-assisted ureteral access sheath and minimally invasive percutaneous nephrolithotomy for 1-2 cm infectious upper ureteral stones: a prospective, randomized controlled study

Objective

To observe the efficacy and safety of retrograde intrarenal surgery combined with vacuum-assisted ureteral access sheath (V-UAS) and minimally invasive percutaneous nephrolithotomy (MPCNL) in patients with 1-2 cm infectious upper ureteral stone.

Patients and methods

A total of 173 patients with 1-2 cm infectious upper ureteral stone were prospectively randomized into two groups. Eighty-six in the V-UAS group and 87 cases as control in the MPCNL group. The SFRs at different times (Postoperative 1 day, 2nd week and 4th week) was considered as the primary outcome of the study. The secondary end points were operative time, postoperative hospital stay and operative complications.

Results

There was no obvious difference between two groups in patients' demographics and preoperative clinical characteristics (all P > 0.05). Postoperative data showed that the SFR at postoperative 1 day in the V-UAS group was significantly lower than that in the MPCNL group (73.2% vs. 86.2%, P = 0.034). However, there was no statistical significance between two groups in SFRs during postoperative 2 weeks and 4 weeks (All P > 0.05). The levels of WBC, CRP and PCT were all significant lower in the V-UAS group than those in the MPCNL group at the postoperative 24 h and 48 h (all P < 0.05). Postoperative complications included fever (≥38.5°C), bleeding, pain and urosepsis. In terms of the rates of fever, pain and urosepsis, MPCNL group were all significantly higher than those in the V-UAS group (10.3 vs. 2.4%, P = 0.031; 14.9 vs. 2.4%, P = 0.003; 4.6 vs. 0.0%, P = 0.044; respectively). No significant difference was found between two groups in bleeding. Meanwhile, postoperative hospital stay in the V-UAS group was more shorten than that in the MPCNL group (3.7 vs. 5.9 days, P < 0.001).

Conclusions

Our study showed that RIRS with V-UAS, a new partnership to treat 1-2 cm infectious upper ureteral stones, was satisfying as it achieved a high SFR rate and a low rate of infectious complications. This method was safe and reproducible in clinical practice.

Novel flexible vacuum-assisted ureteral access sheath(FV-UAS) can actively control intrarenal pressure and obtain a complete stone-free status

OBJECTIVES

To compare the safety and effectiveness of a novel flexible vacuum-assisted ureteral access sheath (FV-UAS) and traditional ureteral access sheath (UAS) in simulating retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

Amanometric model was established in porcine kidneys to observe the change inintrarenal pressure in the FV-UAS and traditional UAS groups at different irrigation fluid velocities of 30 ml/min, 50 ml/min, 80 ml/min, and 100 ml/min. Establish a kidney stone model (with 0.2 g, dry, ≤ 5 mm stones) to simulate RIRS. A total of 20 porcine kidneys wererandomly numbered from 1 to 20 (FV-UAS group, 1-10; traditional UAS group, 11-20). The stone volume clearance rate and operation time were compared between the two groups. [" Stone volume clearance rate= (1-(residual stone volume)/(preoperative stone volume))×100%" )]. Stones volume was obtained by computed tomography (CT) preoperatively and postoperatively.

RESULTS

FV-UAS can follow flexible ureteroscopy (f-URS) to cross the ureteropelvic junction (UPJ) and into the renal pelvis and calyces. FV-UAS can actively make intrarenal pressure (IRP) less than 10 cmH2O by adjusting the negative values atdifferent irrigation fluid velocities. The mean residual stone volume of the FV-UAS vs. traditional UAS groups was33.7 mm3 vs. 92.5 mm3 (P = 0.017). The mean stone volume clearance rates of the FV-UAS vs. traditional UAS groups were 98.5 % and95.9 %, respectively (P = 0.017). Seven cases achieved complete stone-free status in the FV-UAS group. All patients hadresidual fragments postoperatively in the traditional UAS group.

CONCLUSIONS

FV-UAS can follow f-URS to cross the UPJ and into the renal pelvis and calyces, avoiding the interference of UPJ in controlling IRP. FV-UAS can actively control the IRP to be reduced to the desired range by adjusting the negative value under any irrigation fluid velocity. FV-UAS close to the stone can achieve complete stone-free in RIRS.