Wideband Doppler Ultrasound-guided Mini-endoscopic Combined Intrarenal Surgery as an Effective and Safe Procedure for Management of Large Renal Stones: A Preliminary Report

Comparison of Percutaneous Renal Access Between Robot-Assisted Fluoroscopy Guidance Using the Bi-Plane Method and Ultrasound Guidance: A Multicenter Randomized Control Benchtop Study

Purpose: To evaluate the efficacy of supine percutaneous renal access by robot-assisted (RA) fluoroscopy and ultrasound (US) guidance in terms of procedural outcomes and surgeon workload. Methods: We conducted a multicenter, randomized, controlled benchtop study involving 32 urologists using a renal phantom model. RA puncture was performed using the developed version of automated needle targeting with X-ray (ANT-X), which determines the direction of the needle. US puncture was performed under US guidance. The primary endpoint was the single-puncture success rate, and the secondary outcomes were the procedural time for each step, time of fluoroscopic exposure, and workload assessment. Results: The single-puncture success rates were 90.6% and 56.3% for RA and US punctures, respectively (p < 0.01). In RA puncture, the median device setup time was 120 seconds longer, the median total procedural time was 100 seconds longer, the median time of fluoroscopic exposure was 40 seconds longer, the median needle puncture time was 17 seconds shorter, and the distance from the target sphere was 1 cm shorter than those in US puncture (all p < 0.01). The mental and physical task workload, effort required by the surgeons, frustration felt by the surgeons, and overall National Aeronautics and Space Administration Task Load Index scores were lower in the RA puncture group than in the US puncture group (p = 0.01, p = 0.046, p < 0.01, p = 0.021, and p ≤ 0.01, respectively). Conclusions: RA puncture using ANT-X, which can also be used for puncture in the supine position, offers advantages over renal puncture in terms of accuracy and surgical workload.

Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones

To establish a safer and more efficient treatment strategy with mini-endoscopic combined intrarenal surgery (ECIRS), the present study aimed to develop models to predict the outcomes of mini-ECIRS in patients with renal and/or ureteral stones. We retrospectively analysed consecutive patients with renal and/or ureteral stones who underwent mini-ECIRS at three Japanese tertiary institutions. Final treatment outcome was evaluated by CT imaging at 1 month postoperatively and stone free (SF) was defined as completely no residual stone or residual stone fragments ≤ 2 mm. Three prognostic models (multiple logistic regression, classification tree analysis, and machine learning-based random forest) were developed to predict surgical outcomes using preoperative clinical factors. Clinical data from 1432 ECIRS were pooled from a database registered at three institutions, and 996 single sessions of mini-ECIRS were analysed in this study. The overall SF rate was 62.3%. The multiple logistic regression model consisted of stone burden (P < 0.001), number of involved calyces (P < 0.001), nephrostomy prior to mini-ECIRS (P = 0.091), and ECOG-PS (P = 0.110), wherein the area under the curve (AUC) was 70.7%. The classification tree analysis consisted of the number of involved calyces with an AUC of 61.7%. The random forest model showed that the top predictive variable was the number of calyces involved, with an AUC of 91.9%. Internal validation revealed that the AUCs for the multiple logistic regression model, classification tree analysis and random forest models were 70.4, 69.6 and 85.9%, respectively. The number of involved calyces, and a smaller stone burden implied a SF outcome. The machine learning-based model showed remarkably high accuracy and may be a promising tool for physicians and patients to obtain proper consent, avoid inefficient surgery, and decide preoperatively on the most efficient treatment strategies, including staged mini-ECIRS.

The Consecutive 200 Cases of Endoscopic-Combined Intrarenal Surgery: Comparison between Standard and Miniature Surgeries

Background and Objectives: Percutaneous nephrolithotomy (PCNL) is still the gold-standard treatment for large and/or complex renal stones. Endoscopic combined intrarenal surgery (ECIRS) was developed with the goal of minimizing the number of access tracts of PCNL while simultaneously improving the one-step stone-free rate (SFR). The aim of this study was to share the experience of the consecutive 200 cases of ECIRS in one institute and analyze surgical outcomes of mini-ECIRS and standard ECIRS. Materials and Methods: We performed ECIRS for 200 adult patients between July 2017 and January 2020. An ECIRS was performed with the patient under general anesthesia in the intermediate-supine position. Surgeries were finished using a tubeless technique with a simple ureteral stent insertion. Results: There were significant differences in the mean maximal stone length (MSL), the variation coefficient of stone density (VCSD), the linear calculus density (LCD), the Seoul National University Renal Stone Complexity (S-ReSC), and the modified S-ReSC scores in stone characteristics, and estimated blood loss (EBL) and operation time in peri-operative outcomes between conventional and mini-ECIRS. After propensity-score matching, there was only a difference in EBL between the two groups. In logistic regression models, MSL [odds ratio (OR) 0.953; 95% confidence interval (CI) 0.926-0.979; p < 0.001], LCD (OR 4.702; 95% CI 1.613-18.655; p = 0.013) were significant factors for the success rate after ECIRS. Conclusions: In patients who underwent a mini-ECIRS, the stones were relatively smaller and less complex, and the operation time was shorter. However, if the size of stones was similar, there was no difference in the success rate, but EBL was lower in mini-ECIRS than in standard surgery.

Application of ultrasound imaging in the treatment of urinary tract stones

Urinary tract stones are a common clinical condition that affect millions of individuals worldwide. The management of these stones has evolved significantly over the past 70 years, and ultrasound imaging has emerged as a valuable tool for diagnosis, treatment planning, and follow-up. This review aims to provide an overview of the application of ultrasound imaging in the treatment of urinary tract stones, highlighting its advantages, limitations, and current advancements in the field.

Evolution and current applications of endoscopic combined intrarenal surgery: a scoping review from back to the future

PURPOSE OF REVIEW

To systematically review the evolution of techniques, technology, clinical utility, limitations and possible future applications of endoscopic combined intrarenal surgery (ECIRS) for ureteral and kidney stones.

RECENT FINDINGS

The literature search was performed on 18th January 2023 using PubMed, EMBASE and Scopus. 35 studies were included. Among them, six were reviews. Since its introduction in 2008, ECIRS has evolved and improved. ECIRS can be performed in different patient position, such as modified supine Valdivia position by Galdakao, prone position with split-leg and supine position with good outcomes. Instrument miniaturization has also been introduced in ECIRS making it doable in an ambulatory setting. ECIRS showed shorter operative time, lower complication rate, and retreatment compared with conventional PCNL. Operative outcomes of mini-ECIRS are better than mini-PCNL alone. ECIRS also showed good outcomes in impacted upper ureteric stones. Recently, some studies have explored the robotic-assisted kidney puncture in ECIRS that avoided multitrack surgery, especially in anomalous kidney and staghorn stones.

SUMMARY

ECIRS is ready for primetime in endourology and can be considered the next gold-standard for a personalized stone approach in complex kidney stones.

Miniaturization in percutaneous nephrolithotomy: What is new?

Objective

To summarize recent advancements in mini-percutaneous nephrolithotomy (mini-PCNL) in surgical technique, stone removal strategy, lithotripsy, and surgical model from the current literature.

Methods

We conducted a narrative review of relevant English-language articles up to October 2022 using the PubMed and Web of Science databases. The following keywords were used in the search: "percutaneous nephrolithotomy", "minimally invasive percutaneous nephrolithotomy", "mini-PCNL", "mini-perc", "mPCNL", and "miniaturization".

Results

A series of new progress has been made in many aspects of mini-PCNL, such as further reduction of tract size-needle perc and further improvement of robotic-assisted PCNL-artificial intelligence-powered robotic devices.

Conclusion

Many studies and trials have been conducted to reduce morbidity and increase the safety and effectiveness of mini-PCNL. It is crucial to realize that miniaturization of PCNL requires not only a smaller percutaneous tract size, but also an adjustment strategically in renal access, stone removal, lithotripsy, and surgical model in general. More large-scale prospective research needs to be carried out to further validate and optimize the safety and effectiveness of mini-PCNL.

Impact of pelvicalyceal anatomical variation on surgical outcomes of endoscopic combined intrarenal surgery

Objectives

The objective of this work is to investigate the impact of the pelvicalyceal anatomical system (PCS) on calyceal stone formation and surgical outcomes of endoscopic combined intrarenal surgery (ECIRS) for renal and/or proximal ureteral stones with a diameter >15 mm.

Patients and methods

PCS was classified as Type I (single pelvis) or Type II (divided pelvis) according to the simple anatomical Takazawa classification. Using prospectively collected data from January 2016 to April 2020, 219 patients were retrospectively reviewed. After excluding patients who underwent a staged procedure, had hydronephrosis greater than grade 2, prior nephrostomy tubes, and failed to access the renal collecting system, 115 patients (Type I: 81, Type II: 34) were included, and the distribution of calyceal stones and surgical outcomes in ECIRS were compared between Types I and II PCS.

Results

The median number of renal stone calyces in the Type II group was significantly more than that in the Type I group (p = 0.016). In particular, the Type II group possessed more upper stone calyces. Multivariate logistic regression analysis revealed that Type II PCS was associated with an increased odds ratio (OR) for the presence of upper stone calyces (OR: 2.93, p = 0.018). The stone-free (SF) status at 1 month after surgery, confirmed by abdominal plain radiography, was significantly higher in the Type I group compared with that in Type II (67.9% vs. 39.4%, respectively; p = 0.006). The requirement for additional surgical interventions was significantly higher in the Type II group compared with that in Type I (35.4% vs. 7.4%, respectively; p < 0.001). Multivariate analysis revealed that the number of stone calyces (OR: 4.26; p = 0.001) and Type II PCS (OR: 3.43; p = 0.009) were independent predictors of residual stones after ECIRS.

Conclusion

We first revealed that the anatomic properties of PCS play a role in both upper calyceal stone formation and in the success of the ECIRS procedure. Because the SF rate in Type II PCS was significantly lower than that in Type I PCS, additional percutaneous nephrolithotomy tracts might be required, even for ECIRS.

Can trajectory nor-epinephrine infiltration reduce blood loss during percutaneous nephrolithotomy? A double-blinded randomized controlled trial

PURPOSE

To determine the efficacy and safety of trajectory infiltration with 1:150 000 Norepinephrine (NE) in reducing blood loss during percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

This is a prospective randomized double-blinded placebo-controlled trial. In all, 140 consecutive patients underwent PCNL for the management of large renal calculi. They were randomly assigned (1:1) to one of either study groups, the NE-PCNL group (70 patients whose PCNL-trajectory was infiltrated by NE) or the Placebo group (saline PCNL) (70 patients whose PCNL tracts were infiltrated by normal saline). Procedure-related blood loss (the primary outcome) was assessed and statistically analyzed. Also, all other procedure-related events and complications were recorded and compared.

RESULTS

The median blood loss was 378 ml (IQR: 252-504) in the NE-PCNL group versus 592 ml (IQR: 378-756) in the S-PCNL group (p < 0.0001). In addition, Hemoglobin and Hematocrit deficits were lower in NE-PCNL (p < 0.05). Patients who were randomized to the NE-PCNL group had a higher immediate stone-free rate (SFR) (80%) compared with those of the S-PCNL group (70%) (p = 0.034). However, no statistical differences were found in the final SFR. The reported overall complications between the 2 groups were similar (p > 0.05). Indeed, bleeding-related complications were 1 (1.4%) versus 10 (14.3%) for NE-PCNL and S-PCNL, respectively (p = 0.009).

CONCLUSIONS

Trajectory infiltration of PCNL tracts by NE was found to be effective and safe in mitigation of PCNL-related blood loss. This step is a timeless and cost-effective as NE is readily available in surgical theaters and of very low cost.

Endoscopic combined intrarenal surgery in the prone split-leg position versus Galdakao-modified supine Valdivia position for the management of partial staghorn calculi

OBJECTIVE

To evaluate and compare the outcome of ECIRS in the treatment of partial staghorn renal calculi in both prone split-leg positions versus GMSV positions with regard to; technical aspects, success rate, operative time, complications, safety, and effectiveness of both approaches.

PATIENTS AND METHODS

Between October 2018 and August 2021, 66 patients with partial staghorn calculi were enrolled in this prospective comparative study. Patients were randomly divided according to a 1:1 ratio into two groups. Group A included 33 patients who were treated by (ECIRS) in the prone split-leg position, and group B included 33 patients who were treated by (ECIRS) in the Galdakao-modified supine Valdivia (GMSV) position.

RESULTS

No significant statistical difference between both groups regarding the mean age (p = 0.448), mean body mass index (BMI) (p = 0.137), mean stone burden (p = 0.435), mean operative time (p = 0.541) and the number of calyces located in branched stones (p = 0.628). The mean hospital stay was 6.71 ± 1.12 days for group A and 6.66 ± 1.10 days for group B patients (p = 0.724). The final SFR was achieved in (29)87.87% and (30)90.9% of group A & B patients, respectively (p = 0.694). No significant difference was detected between both groups in perioperative complication rates.

CONCLUSION

ECIRS is safe and effective in treating partial staghorn calculi either in the prone split-leg position or in the Galdakao-modified supine Valdivia position, with comparable outcomes and no statistically significant difference between both positions.

Application of a new position in endoscopic combined intrarenal surgery: modified prone split-leg position

Background

Endoscopic combined intrarenal surgery (ECIRS) is well established as a minimally invasive procedure for the treatment of multiple urolithiasis. The position is the key to the perfect combination of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). Galdakao-modified supine Valdivia (GMSV) and prone split-leg positions are widely used. However, both positions have their own advantages and disadvantages. This study aimed to evaluate the effect of ECIRS in the treatment of multiple urolithiasis in the modified prone split-leg position.

Patients and methods

A total of 96 patients with multiple urolithiasis underwent ECIRS in modified prone split-leg position from September 2017 to January 2021. Relevant demographic and clinical data were analysed retrospectively. Clinical outcomes, such as the stone free rate, complications and postoperative hospital stay were evaluated. The chi-square test was used to compare categorical variables and Student’s t test was applied for continuous variables of the treatment groups.

Results

The mean renal stone size was 32.5 ± 10.7 mm and renal stone surface area was 712.2 ± 264.8 mm². The mean ureteral stones size was 24.8 ± 12.3 mm. The mean surgical time was 82.2 ± 38.3 min. The incidence of complications was 16.7%, and they were mainly grade 1 and grade 2. No complications occurred above grade 3. The stone was completely removed in 75 (78.1%) patients in a single operation. The risk factors affecting the stone-free rate of ECIRS were analysed, and only the number of involved calyces by stone was found to be significant (p = 0.01).

Conclusion

ECIRS is safe and effective in the treatment of multiple renal calculi or multiple renal calculi with ipsilateral ureteral calculi in the modified prone split-leg position. The modification of the prone split-leg position makes the retrograde operation more convenient, which is conducive to the combination of RIRS and PCNL.

Comparison of the safety and efficacy between the prone split-leg and Galdakao-modified supine Valdivia positions during endoscopic combined intrarenal surgery: A multi-institutional analysis

OBJECTIVES

To evaluate the safety and efficacy of the prone split-leg and the Galdakao-modified supine Valdivia positions during endoscopic combined intrarenal surgery.

METHODS

A multi-institutional, retrospective cohort study was conducted between January 2014 and December 2018. The stone-free and complication rates were compared between the prone split-leg and the Galdakao-modified supine Valdivia positions. Anatomical variations were evaluated using contrast-enhanced computed tomography imaging.

RESULTS

In total, 118 and 100 patients underwent endoscopic combined intrarenal surgery in the prone split-leg and Galdakao-modified supine Valdivia positions, respectively. Renal punctures in the prone split-leg position were predominantly executed through the lower calyces (78.0%), whereas those in the Galdakao-modified supine Valdivia position were primarily performed through the middle calyces (64.0%; P < 0.001). Surgical duration in the prone split-leg position was significantly shorter than that in the Galdakao-modified supine Valdivia position (106.5 vs 126.0 min; P = 0.0459). There were no significant differences in the stone-free rate between the two positions (78.8% vs 76.0%; P = 0.629). Incidences of urinary tract injury (P = 0.033) and febrile urinary tract infection (23.7% vs 10.0%; P = 0.011) in the prone split-leg position were significantly higher than that in the Galdakao-modified supine Valdivia position. The tilt of the major renal axis was significantly greater in the prone position than the corresponding values in the oblique position (19.4° vs 8.5°; P = 0.019).

CONCLUSIONS

Anatomical variation might result in the differences of renal puncture calyx. Endoscopic combined intrarenal surgery in the Galdakao-modified supine Valdivia position may bring equal stone-free status, with a longer surgical time but fewer complications including febrile urinary tract infection and urinary tract injury than the prone split-leg position.

Evaluating outcomes of complete supine percutaneous nephrolithotomy for staghorn vs multiple non-staghorn renal stones: a 10-year study

PURPOSE

To evaluate the outcomes of complete supine percutaneous nephrolithotomy (csPCNL) for staghorn stones and multiple large non-staghorn stones.

METHODS

The records of 886 patients who underwent csPCNL from September 2009 to October 2019 were considered. Out of them, 201 cases met the eligibility criteria and they were divided into three groups: 63 cases of staghorn, 68 cases of multiple medium (20 mm < diameter ≤ 30 mm) non-staghorn and 70 cases of multiple large non-staghorn (> 30 mm) stones. Almost all outcomes and stone-related factors were analyzed.

RESULTS

There was not any significant difference regarding age, body mass index, history of urinary tract infection, transfusion rate, complication rate, pre and post-surgery serum creatinine, hemoglobin drop and total hospital stay between the three groups. Stone free rate was 98.5% in multiple medium group, 97.1% in multiple large group and 84.1% in staghorn group (P = 0.001). The operation duration was significantly shorter for the multiple medium group (P < 0.001) but it was not significantly different between the multiple large non-staghorn and staghorn group.

CONCLUSION

The results demonstrated that almost all outcomes were not significantly different between the three groups (especially between staghorn and larger non-staghorn ones). These findings reveal that surgeons could choose csPCNL for treatment of staghorn stones and multiple large non-staghorn stones and consider staghorn stones as challenging as multiple large (especially diameter > 30 mm) non-staghorn stones.

Tips and Tricks to Improve Ergonomics, Efficacy, Versatility, and Overcome Limitations of Micro Percutaneous Nephrolithotomy

Percutaneous Nephrolithotomy (PCNL) has evolved over the decades from Standard to Mini to Ultramini PCNL to Micro-perc, with miniaturisation being the dominant theme and supine approach gaining momentum world over.

Aim: In literature, miniaturised PCNL with microperc needle access system has raised concerns of intrarenal pressure and has some limitations with its success for larger stones. Our tips and tricks explain how to overcome these pitfalls by utilising the full construct of the needle system to its maximum potential. These will in turn help make the procedure versatile, precise, ergonomical, and enhance a surgeon's experience with improved outcomes for patients especially in large renal stones.

Materials and Methods: We describe the limitations of microperc needle access as stated in literature and proposals by the co-authors using microperc for miniaturised access on how to overcome the same.

Results: A simplified table describing the limitations and tips and tricks on overcoming these is provided for quick reference.

Conclusion: As Technological advancements and techniques for miniaturised access in urolithiasis improve, we believe our suggestions will help surgeons overcome the quoted limitations of microperc needle access for miniaturised PCNL, making this a versatile, safe and efficacious technique even in large and complex stones. A multi centre trial will be the best way to validate the suggestions proposed in this article.

Preoperative imaging in staghorn calculi, planning and decision making in management of staghorn calculi

Objective

Staghorn calculi present a particular and challenging entity of stone morphology. Treatment is associated with lower stone-free rates and higher complication rates compared to non-staghorn stones. In this review we looked for the most relevant data on preoperative imaging and access planning to help decision making for percutaneous surgery with this complex condition.

Methods

We conducted a PubMed search of publications in the past 2 decades that include relevant information on the planning for management of staghorn stones. Non-contrast computerized tomography (NCCT) is indeed the standard imaging tool for percutaneous nephrolithotomy (PCNL); additional tools such as three-dimensional computed tomography (CT) reconstruction of the staghorn calculus may help plan access in complex cases. Ultrasound guided percutaneous access may be considered for staghorn stones when planning upper pole access in kidney malposition or complex intrarenal anatomy or with complex body habitus. Wideband doppler ultrasound and real-time virtual sonography can assist. New technologies to improve kidney access such as Uro Dyna-CT or electromagnetic sensor have been reported, but have not shown utilization in staghorn cases. Staghorn morphometry-based prediction algorithms may predict the number of tract(s) and stage(s) for PCNL monotherapy. Lower pole access can be equally effective as upper pole when planning for staghorn and complex stones, with significantly less complications rate; Stone-Tract length-Obstruction-Number of involved calyces-Essence of stone density (STONE) nephrolithometry seems to be the best system to predict outcomes of PCNL in staghorn cases. There is a growing trend of endoscopic combined intrarenal surgery (ECIRS) in concordance with PCNL to treat larger stones. Conservative management of staghorn calculi is an undesired option, but can be an alternative for a carefully selected group of high-risk patients.

Conclusion

Staghorn stones may lead to deterioration of renal function and life-threatening urosepsis. This entity should be managed aggressively with planning ahead for surgery using the different tools available as the cornerstone for a successful outcome.

Trans-tract electrocoagulation can decrease the need for postoperative nephrostomy tube after endoscopic combined intrarenal surgery

AIM

To assess the efficacy and safety of trans-tract electrocoagulation at the end of endoscopic combined intrarenal surgery for renal or ureteral stones.

METHODS

The present study included patients who underwent endoscopic combined intrarenal surgery from May 2010 to March 2018. After June 2013, the trans-tract electrocoagulation procedure, to coagulate bleeding from the access tract using a resectscope was carried out at the end of the operation. We compared the patients' background and surgical outcomes between patients with and without trans-tract electrocoagulation.

RESULTS

Between the trans-tract electrocoagulation (n = 225) and non-trans-tract electrocoagulation (n = 72) groups, the stone number was significantly smaller (1:2:3 or more, 126:72:27 vs 59:10:3, P = 0.001) and the initial stone-free rates were significantly higher (80% vs 72%, P = 0.006) in the trans-tract electrocoagulation group than in the non-trans-tract electrocoagulation group. Patients experienced a higher nephrostomy tube-free rate (67% vs 26%, P < 0.0001), shorter postoperative catheterization time (2.8 ± 3.8 vs 5.4 ± 5.0 days, P = 0.002) and shorter hospital stay (6.5 ± 3.6 vs 8.8 ± 5.0 days, P = 0.0001) in the trans-tract electrocoagulation group than in the non-trans-tract electrocoagulation group.

CONCLUSIONS

Trans-tract electrocoagulation in endoscopic combined intrarenal surgery is a safe and efficient procedure that decreases the need for nephrostomy tube placement after surgery.

Successful Ultra-Minimally Invasive Endoscopic Intrarenal Surgery for 2-Year-Old Boy with Bilateral Cystine Kidney Stones Over 2 cm

Background: Treatment of upper urinary tract stones measuring >2 cm in children aged <3 years is challenging. Although adult-sized instruments are usually available, in pediatric populations such instruments seem unreasonable and unfit for children with small kidneys and narrow ureters. We use ultra-miniaturized endoscopes and instruments to reduce the damage to normal tissues in pediatric patients.

Case Presentation: We treated a 2-year-old boy with >2-cm bilateral cystine kidney stones. We decided to perform retrograde intrarenal surgery using an ultrathin (4.5F) semi-rigid ureteroscope for the right kidney stone (2.0 × 1.2 cm) in the lithotomy position and super ultra-minimally invasive endoscopy combined with intrarenal surgery with a percutaneous 8.5F to 9.5F tract sheath for the left kidney stone (3.5 × 2.4 cm) under the Barts modified Valdivia position. These procedures were successful for the bilateral kidney stones. Postoperatively, the patient was stone-free without major complications.

Conclusion: We believe that ultra-minimally invasive endoscopic intrarenal surgery is safe and efficient in pediatric patients. Furthermore, the Barts modified Valdivia position was safely utilized in our 2-year-old patient with multiple large kidney stones.