Reducing kidney motion: optimizing anesthesia and combining respiratory support for retrograde intrarenal surgery: a pilot study

Feasibility of respiratory synchronization for laser lithotripsy using a robotic retrograde intrarenal surgery system Zamenix™ in an in-vitro model

OBJECTIVES

This study aims to investigate the improvement of stone fragmentation efficiency and safety in robotic-assisted retrograde intrarenal surgery (RIRS) that implements the respiratory motion synchronization using an in vitro model.

MATERIALS AND METHODS

Laser lithotripsy was performed in three groups: manual procedure (group M), robotic procedures without respiratory synchronization (group RNR), and robotic procedures with respiratory synchronization (group RR). The study assessed fragmentation time, laser time, number of mucosal contacts, and total energy used. Two surgeons having different experience of conventional RIRS (> 2500 and < 500) were participated.

RESULTS

In overall results of the two surgeons, the fragmentation time significantly decreased to 74.8% in group RNR (P = 0.012) and 65.0% in group RR (P = 0.001), compared to group M. The laser time was significantly shorter in group RR compared to the group M (P = 0.003). The number of mucosal contacts was significantly reduced to 37.4% in group RNR (P = 0.048) and it was 34.0% in group RR, compared to group M. The total energy significantly decreased in group RR compared to group M (P = 0.011). There were no significant differences between group RR and RNR across all outcomes in the overall results of the two surgeons. For less experienced surgeon, the fragmentation time was significantly shorter in group RR compared to group RNR (P = 0.013).

CONCLUSIONS

Robotic-assisted RIRS resulted in reduced fragmentation time, laser time, mucosal contacts, and total energy compared to manual RIRS during laser lithotripsy. The incorporation of respiratory synchronization in robotic-assisted RIRS reduced laser time compared to manual RIRS and shortened the fragmentation time compared to the robotic-assisted RIRS without respiratory synchronization, particularly for less experienced surgeon. These initial results demonstrated the feasibility of robotic-assisted RIRS with respiratory synchronization, highlighting its potential to improve procedural efficiency and safety.

General anaesthesia with gated or controlled mechanical ventilation and its influence on peri and post operative outcomes of retrograde intra renal surgery when using flexible and navigable suction access sheath, an EAU-endourology and Global FANS collaborative study group: a prospective study

BACKGROUND

Retrograde intrarenal surgery (RIRS) is a preferred treatment for renal stones, yet challenges such as kidney movement due to respiration hinder surgical precision and outcomes. The introduction of flexible and navigable suction ureteral access sheaths (FANS) and novel techniques like gated respiration aim to improve stone-free rates (SFR) and reduce complications. This study evaluates the impact of gated respiration on perioperative outcomes in RIRS with FANS.

METHODS

A prospective multicenter study enrolled 562 adult patients undergoing RIRS with FANS under general anesthesia. Patients were divided into two groups: non-gated respiration (Group 1) and gated respiration (Group 2). Stone-free status (SFS) was assessed at 30 days using NCCT scans. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤ 2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments > 4 mm. Procedural efficiency, perioperative complications, and surgeon-reported outcomes were compared.

RESULTS

Patients in Group 2 had significantly higher zero residual fragment (Grade A) rates (64.2% vs. 59%) and overall SFR (Grade A + B: 98.3% vs. 91.3%, p = 0.001). Gated respiration improved sheath navigation (91.2% vs. 85.1%, p = 0.038) and visibility during lithotripsy (p = 0.004), while reducing complications like mild bleeding due to sheath movement (3.1% vs. 11.2%, p < 0.001). Logistic regression identified gated respiration as a significant predictor of SFS (OR 6.26, 95% CI 2.28-22.6, p < 0.001).

CONCLUSION

Gated respiration synergistically enhances the efficacy of FANS in RIRS, improving SFR, procedural safety, and surgeon experience. This study highlights the importance of respiratory control as an adjunct to RIRS, emphasizing the need for interdisciplinary collaboration between surgical and anesthesiology teams.

Does tidal volume during mechanical ventilation affect pediatric retrograde intrarenal surgery outcomes?

PURPOSE

The aim of the study was to analyze the effect of tidal volume during mechanical ventilation (MV) on pediatric retrograde intrarenal surgery (RIRS) outcomes.

METHODS

The data of patients who underwent RIRS between January 2018 and January 2023 were retrospectively analyzed. Patients under the age of 18 who underwent RIRS and whose data were available were included in the study. Patients were divided into two groups, ≤ 7 ml/kg (Group 1) and > 7 ml/kg (Group 2), according to the tidal volume during MV. Demographic data, clinical characteristics, and perioperative and postoperative data of the patients were statistically compared in both groups.

RESULTS

A total of 83 patients were enrolled, with a mean age of 6.9 ± 4.5 (1-17) years and a mean stone size of 11.7 ± 5.4 (5-33) mm. There were 31 patients in Group 1 and 52 patients in Group 2. The demographic data and clinical characteristics of the patients in both groups were comparable. There was no statistically significant difference between the two groups regarding stone-related (side, size, density, number, and location) and surgical (access sheath and basket use, operation time, fluoroscopy time, or postoperative stenting rates, complication rates) parameters. In the first month, the stone-free rate was higher in Group 1 than in Group 2 (90.3% vs. 71.1%, p = 0.03). No high-grade or anesthesia-related complications were observed in any of the patients.

CONCLUSION

Reducing tidal volume in pediatric RIRS may improve the stone-free rate by facilitating laser targeting and increasing operative field stability and surgical comfort.

Predictive Modeling Is a Reliable Indicator in Determining Excessive Renal Mobility Single-Center Randomized Study

Purpose: Excessive kidney mobility is an underestimating challenge for surgeons during retrograde intrarenal surgery (RIRS) and extracorporeal shock wave lithotripsy (ESL). There is no technique approved as a gold standard procedure for reducing excessive kidney mobility. The study aimed to uncover predictive factors for determining excessive renal mobility by utilizing clinicodemographic characteristics and noncontrast computed tomography (NCCT) data. Materials and Methods: The patients were categorized into two groups based on the presence of excessive renal mobility. Patients were scanned with a 16-channel, multislice NCCT, and images were captured utilizing a 16 × 1.25 mm collimation, 5 mm slice thickness. Many parameters including the origin angle of the renal artery, renal artery, vein length, diameter, the area and length of the psoas muscle, and perirenal and pararenal fatty tissue were measured on the images and analyzed. The data were analyzed using multivariate logistic regression, and the receiver operating characteristic curve model and we used predictive modeling based on three significant parameters. Results: Between May 2023 and May 2024, a total of 140 patients with and without excessive renal mobility enrolled into study. After multivariate analysis, increasing renal vein length and renal artery origin angle results in higher renal motility (odds ratio [OR]: 0.982; 95% confidence interval [CI]: 0.966-0.998; p = 0.030 and OR: 0.973; 95% CI: 0.948-0.999; p = 0.044; respectively). It also observed that an increase in tidal volume led to a reduction in renal mobility (OR: 1.015; 95% CI: 1.007-1.024; p = 0.001). Predictive modeling was designed based on these outcomes. This predictive modeling accurately estimates the presence of excessive renal mobility with improved 59% specificity and 65% sensitivity (p < 0.001, area under the curve 0.757; CI: 0.671-0.843). Conclusion: Physicians may predict the presence of excessive renal mobility via the predictive modeling mentioned in the current article. They may perform manipulations to reduce kidney mobility prior to ESL and RIRS.

The Effect of Anesthesia Type on the Stability of the Surgical View on the Monitor in Retrograde Intrarenal Surgery for Renal Stone: A Prospective Observational Trial

Background and Objectives: Retrograde intrarenal surgery (RIRS) is a minimally invasive technique for nephrolithiasis. RIRS is performed via a monitor screen displaying a magnified surgical site. Respiration can affect the stability of the surgical view during RIRS because the kidneys are close to the diaphragm. The purpose of this trial is to compare the effect of anesthesia type on the stability of the surgical view during RIRS between spinal anesthesia and general anesthesia. Materials and Methods: Patients were allocated to the general anesthesia group or spinal anesthesia group. During surgery, movement of the surgical field displayed on the monitor screen was graded by the first assistant on a 10-grade numeric rating scale (0-10). Next, it was also graded by the main surgeon. After surgery, we evaluated the discomfort with the anesthesia method for all patients. Results: Thirty-four patients were allocated to the general anesthesia group and 32 patients to the spinal anesthesia group. The average values of the two surgeons for surgical field oscillation grade showed vision on the monitor screen was more stable in the general anesthesia group than the spinal anesthesia group (3.3 ± 1.6 vs. 5.0 ± 1.6, p < 0.001). The degrees of the inconvenience of the surgery did not differ between the groups (0.7 ± 1.8 vs. 1.6 ± 2.6, p = 0.114), even though more patients reported inconvenience with a grade of 3 or more in the spinal anesthesia group (8.8% vs. 28.1%, p = 0.042). Conclusions: In terms of the visualization of the surgical site, general anesthesia might provide a more stable surgical view during RIRS compared to spinal anesthesia without increasing inconvenience induced by the type of anesthesia.

[THRIVE combined with i-gel laryngeal mask for prolonging apneic oxygenation time in retrograde intrarenal surgery]

OBJECTIVE

To explore the effect of THRIVE combined with i-gel laryngeal mask on the safety of oxygen therapy in apnea and surgical precision of retrograde intrarenal surgery.

METHODS

A total of 120 patients undergoing retrograde intrarenal surgery under general anesthesia with laryngeal mask were randomized into 3 groups (n=40), and after the flexible ureteroscope entered the renal pelvis and located the stones, the patients received assisted ventilation in APPV mode (control group), ventilation with small tidal volume and high respiratory rate (group H), or THRIVE combined with laryngeal mask for oxygen supply without using the ventilator (THRIVE group). The time for lithotripsy by the surgeons, surgeons' satisfaction, diaphragm mobility, and times of urinary tract mucosal injury were recorded, and arterial blood pressure, heart rate, SpO2, PaO2, PaCO2, and pH value were measured before, during and after lithotripsy.

RESULTS

Among the 3 groups, THRIVE group had the shortest time for lithotripsy, best satisfaction of the surgeons, the lowest diaphragmatic mobility of the patients, and the smallest number of mucosal injuries. The arterial blood pressure, heart rate, and SpO2 of the patients did not differ significantly among the 3 groups. At 20 min and 30 min after the start of lithotripsy, PaO2 decreased significantly in group H and THRIVE group; in THRIVE group, PaCO2 increased and pH decreased significantly at 10, 20 and 30 min after the start of lithotripsy. No significant difference was found in oxygenation indicators among the 3 groups upon discharge from the PACU.

CONCLUSION

In retrograde intrarenal surgery, THRIVE combined with i- gel laryngeal mask for oxygen therapy during the anaerobic period can improve the surgical accuracy and maintain the patient's oxygenation index in a controllable range within 30 min.

Indications, preferences, global practice patterns and outcomes in retrograde intrarenal surgery (RIRS) for renal stones in adults: results from a multicenter database of 6669 patients of the global FLEXible ureteroscopy Outcomes Registry (FLEXOR)

PURPOSE

To collect a multicentric database on behalf of TOWER research group to assess practice patterns and outcomes of retrograde intrarenal surgery (RIRS) for kidney stones.

METHODS

Inclusion criteria: age ≥ 18 years, normal renal/calyceal system anatomy, calculi of any size, number, and position.

STUDY PERIOD

January 2018 and August 2021. Stone-free status: absence of fragments > 2 mm, assessed post procedure according to the local protocol (KUB X-Ray and/or ultrasound or non-contrast CT scan).

RESULTS

Twenty centers from fifteen countries enrolled 6669 patients. There were 4407 (66.2%) men. Mean age was 49.3 ± 15.59 years. Pain was the most frequent symptom indication for intervention (62.6%). 679 (10.2%) patients underwent RIRS for an incidental finding of stones. 2732 (41.0%) patients had multiple stones. Mean stone size was 10.04 ± 6.84 mm. A reusable flexible ureteroscope was used in 4803 (72.0%) procedures. A sheath-less RIRS was performed in 454 (6.8%) cases. Holmium:YAG laser was used in 4878 (73.1%) cases. A combination of dusting and fragmentation was the most common lithotripsy mode performed (64.3%). Mean operation time was 62.40 ± 17.76 min. 119 (1.8%) patients had an intraoperative injury of the ureter due to UAS insertion. Mean postoperative stay was 3.62 ± 3.47 days. At least one postoperative complication occurred in 535 (8.0%) patients. Sepsis requiring intensive care admission occurred in 84 (1.3%) patients. Residual fragments were detected in 1445 (21.7%) patients. Among the latter, 744 (51.5%) patients required a further intervention.

CONCLUSION

Our database contributes real-world data to support to a better understanding of modern RIRS practice and outcomes.

Ergonomics and Surgeon Comfort During Flexible Ureteroscopy

The technological advancements of flexible ureteroscopy (FURS) and its accessories have resulted in broadening its indications to include the management of complex renal stones, with long operative time. The surgeon's understanding about the ergonomics of the ureteroscopes and their cognizance of the operation theatre layout helps to improve their performance, including the surgical outcomes. This paper will describe the ergonomics that are involved in conducting FURS which in turn will aid in developing a more conducive surgical environment for the surgeon during the procedure, based on scientific literature review and expert opinions in high-volume centres. Proper surgeon position, well-arranged operation theatre layout, monitor and pedal position, anaesthesia type, and surgical team are important factors to decrease musculoskeletal strains for surgeons and increase work efficiency. Different types of flexible ureteroscope have different characters and knowing these special characters leads to better ergonomics during surgery. Robotic-assisted FURS have shown good safety and ergonomics in clinical application.