Endoscopic Combined Intrarenal Surgery vs Percutaneous Nephrolithotomy for Large and Complex Renal Stone: A Systematic Review and Meta-Analysis

Comprehensive surgical strategy for incarcerated ureteral calculi in the context of double renal pelvis malformations: A case report

INTRODUCTION AND IMPORTANCE

Managing incarcerated ureteral calculi is crucial to prevent obstructive uropathy, renal dysfunction, and urosepsis. Double ureteral malformations with complex calculi pose challenges due to anatomical variations, requiring a multidisciplinary approach.

CASE PRESENTATION

A 35-year-old female with flank pain and hydronephrosis was diagnosed with double renal pelvis malformations and impacted ureteral calculi. A staged approach was used: laparoscopy corrected ureteral malformations, followed by flexible ureteroscopy and percutaneous nephroscopic holmium laser lithotripsy. Complete calculus clearance was confirmed intraoperatively and postoperatively.

CLINICAL DISCUSSION

Double ureteral malformations complicate endoscopic navigation, requiring combined laparoscopic correction and lithotripsy. Challenges included limited space and risk of iatrogenic injury. Holmium laser (0.8-1.2 J) enabled precise fragmentation while preserving mucosa. Preoperative 3D CT urography was vital for surgical planning.

CONCLUSION

At 6-month follow-up, the patient had patent ureteral drainage, no calculus recurrence, and stable renal function. Integrated laparoscopy-endoscopy strategies achieved a 100 % calculus-free rate with minimal complications, emphasizing the importance of image-guided, patient-specific management in complex urolithiasis.

Endoscopic combined intrarenal surgery versus prone percutaneous nephrolithotomy for complex renal stones: critical assessment of a randomized trial

OBJECTIVE

To evaluate the efficacy and safety of endoscopic combined intrarenal surgery (ECIRS) in the Galdakao-Modified Supine Valdivia (GMSV) position versus percutaneous nephrolithotomy (PCNL) in the prone position for managing complex kidney stones.

METHODS

This prospective, randomized study was conducted in the urology departments of Benha University Hospital and Theodor Bilharz Research Institute between June 2021 and May 2024. A total of 60 patients with complex renal stones were randomly assigned to two groups (30 patients each). Group A underwent conventional percutaneous nephrolithotomy (PCNL) in the prone position, while Group B underwent endoscopic combined intrarenal surgery (ECIRS) in the Galdakao-Modified Supine Valdivia (GMSV) position. Data on demographic characteristics, clinical outcomes, perioperative parameters, and stone-free rates (SFR) were collected.

RESULTS

No significant differences were found between the two groups regarding preoperative demographic data and stone characteristics. However, operative time was significantly longer in the PCNL group (119 ± 18 min) compared to the ECIRS group (105 ± 14 min) (P = 0.002). The number of punctures was also significantly higher in the PCNL group than in the ECIRS group (P = 0.001). Immediate success was notably higher in the ECIRS group (83.3%) compared to the PCNL group (53.3%) (P = 0.012). However, no significant difference was observed between the groups concerning eventual success (P = 1.0).

CONCLUSION

ECIRS is a highly effective treatment for complex renal stones, delivering favorable outcomes such as higher single-step stone-free rates, a lower incidence of adverse events, and a reduced need for auxiliary procedures.

Does Mini-Percutaneous Nephrolithotomy Cause Increased Intrarenal Pressure During Percutaneous Nephrolithotomy and is This Mitigated by a Suctioning Sheath? A Randomized Control Trial

Introduction: Intrarenal pressure (IRP) generated during percutaneous nephrolithotomy (PCNL) may have the potential to cause renal damage and/or sepsis. It has been suggested that mini-PCNL (mPCNL) can further increase IRP but that a suctioning sheath may mitigate this elevation. We sought to measure IRP throughout the PCNL process, randomizing patients getting mPCNL to receiving two different mPCNL sheaths, one suctioning and the other nonsuctioning, and then comparing them with patients undergoing standard PCNL (sPCNL) using a 24F sheath. Patients and Methods: Twenty patients meeting the eligibility criteria for mPCNL were randomized into two groups: suctioning mPCNL (s-mPCNL) with a single-step dilator and continuous suction sheath (ClearPetra™, 18F, n = 10) and nonsuctioning mPCNL (ns-mPCNL) with a metallic dilator and sheath (Storz MIP-M™, 17.5F, n = 10). A group of 10 patients undergoing sPCNL using a balloon dilator with a Polytetrafluoroethylene (PTFE) sheath (NephroMax™, 24F, n = 10) were included as a control. IRP was measured with a 0.014″ COMET™ II Pressure guidewire retrogradely positioned in the renal pelvis. Gravity irrigation was utilized. Pressure data captured include baseline IRPs, retrograde pyelogram (RPG), needle entry, fascial dilation, tract dilation, sheath insertion, nephroscopy, and lithotripsy. The primary outcome was differences in mean and peak IRP during each stage. Categorical data were compared using chi-square or Fisher's exact tests. Continuous variables were analyzed using one-way analysis of variance. Results: Peak and mean IRPs (millimeters of mercury or mm Hg) were similar at baseline and during RPG, needle insertion, and fascial dilation in the two experimental groups and in the control group. During tract dilation and sheath placement, both the mPCNL sheaths generated much higher peak IRP compared with the 24F balloon dilation control group but similar to each other (dilation: 36.6 and 38.6 vs 6.9, p < 0.001; sheath placement: 36.6 and 35.3 vs 13.8, p = 0.039). During nephroscopy, ns-mPCNL generated greater peak IRP compared with s-mPCNL and the control group (41.8 vs 19.09 and 24.15; p = 0.019). The highest peak IRP for each group occurred during RPG and when a nephroscope was placed through a narrow infundibulum. Conclusions: Compared with balloon dilation, coaxial dilation with mPCNL sheaths generates significantly higher IRP. During nephroscopy, ns-mPCNL sheaths generate higher IRP compared with standard and suctioning sheaths. Highest IRPs are generated during RPG and when a nephroscope goes through a narrow infundibulum. These findings can inform improved sheath and nephroscope design. Further research assessing the effect of high IRP on postoperative pain, sepsis, and renal injury is needed.

Comparison of radiation exposure for interventional radiology vs urology-guided renal access for percutaneous nephrolithotomy

INTRODUCTION

Radiation exposure during percutaneous nephrolithotomy (PCNL) can vary depending on the method used for renal access. This study aimed to compare fluoroscopy time and dose during PCNL when renal access is achieved via interventional radiology (IR) versus urology.

METHODS

A retrospective review of patients who underwent unilateral PCNL between January 2020 and February 2023 was conducted. Patients were categorized by renal access method: endoscopic combined intrarenal surgery performed by a urologist (ECIRS) or IR-assisted. A Wilcoxon rank-sum test and multivariate analyses were done to compare several parameters of the two groups.

RESULTS

66 patients underwent ECIRS (group 1), and 31 underwent IR-assisted access (group 2). The groups were similar in age, BMI, sex, and stone size. The difference in medians for fluoroscopy dose, fluoroscopy time, operative time and length of stay were statistically significant (p < 0.001). Average fluoroscopy dose (39.6 vs. 327 mGy) and time (1.46 vs. 10.9 min), along with average operative time (1.97 vs. 3.00 h) and length of stay (1.26 vs 3.06 days) were all lower in group 1. In the IR group, a positive correlation was noted between BMI and fluoroscopy dose (p < 0.001), though this correlation was absent with ECIRS.

CONCLUSIONS

PCNL with ECIRS access significantly reduces radiation exposure and operative time compared to IR-assisted access. Additionally, BMI influenced radiation exposure and operative time in the IR group, but not in the ECIRS group. Endoscopic renal access may lower overall radiation exposure and postoperative complications.

Endoscopic Combined Intrarenal Surgery: best practices and future perspectives

INTRODUCTION

Endoscopic Combined Intrarenal Surgery (ECIRS) has emerged as a promising technique for the management of large and complex kidney stones, potentially offering advantages over traditional Percutaneous Nephrolithotomy (PCNL). This study aims to evaluate best practices, outcomes, and future perspectives associated with ECIRS.

MATERIALS AND METHODS

A comprehensive PubMed search was conducted from 2008 to 2024, using MESH terms and the following key words: "ECIRS" and "Endoscopic Combined Intrarenal Surgery" The search yielded 157 articles, including retrospective cohort studies, two randomized controlled trials (RCTs), and four meta-analyses comparing ECIRS with PCNL. Most important findings were summarized regarding indications, patient positioning, kidney access, tract size, surgical outcomes, and complications.

RESULTS

ECIRS demonstrated higher stone-free rate, lower complication rate, and a reduced need for multiple procedures compared to traditional PCNL. Additionally, ECIRS has the potential to integrate new technologies to further enhance outcomes.

CONCLUSION

ECIRS demonstrates significant advantages in the management of large kidney stones. Future research should focus on well-designed RCTs to provide robust evidence of its efficacy, safety, and cost-effectiveness, potentially establishing ECIRS as the first option treatment for complex kidney stones.

Defining a learning curve for urology trainees to achieve renal access without complications in endoscopic combined intrarenal surgery

OBJECTIVES

There is a lack of data on the number of surgeries required for endoscopic combined intrarenal surgery (ECIRS). Accordingly, we aimed to identify the learning curve for ECIRS performed by multiple surgeons.

METHODS

We included 296 patients who underwent ECIRS at our university hospital between 2016 and 2021. A learning curve for percutaneous nephrolithotomy side was calculated considering urology-resident surgeons. The learning curve was retrospectively analyzed for surgical time, renal puncture time, stone-free rate, and complications and corrected for age, body mass index, stone size, computed tomography value, cumulative number of surgeries, and stone location.

RESULTS

This study included cases performed by 32 surgeons, including 30 residents and 2 attending surgeons. The median number of surgeries performed by the residents and attending surgeons prior to this study was 4.5 and 90, respectively. The median number of surgical procedures performed during the training period was seven. The surgical time of the residents decreased as the number of cases increased, reaching a median surgical time of 111 min for the attending surgeons after 16.4 cases. Renal puncture time was achieved in 20.1 cases. Complications related to renal access were observed in 13.0% (34 patients), Clavien-Dindo grade II in 1.9% (5 patients), and grade III or higher in 0.8% (2 patients). Comparing the first to fifth cases with the 21st and subsequent cases, the complication rate improved from 35% to 13%.

CONCLUSION

Our study demonstrated that ECIRS training provided 16-20 cases with a learning curve to achieve acceptable surgical outcomes.

Which Position for Novice Surgeons? Effect of Supine and Prone Positions on Percutaneous Nephrolithotomy Learning Curve

Background and Objectives: Percutaneous nephrolithotomy (PCNL) is a current treatment method with high success rates and low complication rates in treating large kidney stones. It can be conducted in different positions, especially supine and prone positions. PCNL in the supine position is becoming increasingly common due to its advantages, such as simultaneous retrograde intervention and better anesthesia management. This study aimed to assess how the choice of position impacts the PCNL learning curve. Materials and Methods: The results of the first 50 consecutive PCNL cases performed by two separate chief residents as primary surgeons in supine and prone positions in a reference center for stone treatment between August 2021 and January 2023 were evaluated. The two groups' demographic and clinical data, stone-free rates, operation times, and fluoroscopy times were compared. Results: While the mean operation time was 94.6 ± 9.8 min in the supine PCNL group, it was 129.9 ± 20.3 min in the prone PCNL group (p < 0.001). Median fluoroscopy times in the supine PCNL and prone PCNL groups were 31 (10-89) seconds and 48 (23-156) seconds, respectively (p = 0.001). During the operation, the plateau was reached after the 10th case in the supine PCNL group, while it was reached after the 40th case in the prone PCNL group. Conclusions: For surgeons who are novices in performing PCNL, supine PCNL may offer both better results and a faster learning curve. Prospective and randomized studies can provide more robust conclusions on this subject.

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study

Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.

Management of urinary stones: state of the art and future perspectives by experts in stone disease

AIM

To present state of the art on the management of urinary stones from a panel of globally recognized urolithiasis experts who met during the Experts in Stone Disease Congress in Valencia in January 2024. Options of treatment: The surgical treatment modalities of renal and ureteral stones are well defined by the guidelines of international societies, although for some index cases more alternative options are possible. For 1.5 cm renal stones, both m-PCNL and RIRS have proven to be valid treatment alternatives with comparable stone-free rates. The m-PCNL has proven to be more cost effective and requires a shorter operative time, while the RIRS has demonstrated lower morbidity in terms of blood loss and shorter recovery times. SWL has proven to be less effective at least for lower calyceal stones but has the highest safety profile. For a 6mm obstructing stone of the pelviureteric junction (PUJ) stone, SWL should be the first choice for a stone less than 1 cm, due to less invasiveness and lower risk of complications although it has a lower stone free-rate. RIRS has advantages in certain conditions such as anticoagulant treatment, obesity, or body deformity. Technical issues of the surgical procedures for stone removal: In patients receiving antithrombotic therapy, SWL, PCN and open surgery are at elevated risk of hemorrhage or perinephric hematoma. URS, is associated with less morbidity in these cases. An individualized combined evaluation of risks of bleeding and thromboembolism should determine the perioperative thromboprophylactic strategy. Pre-interventional urine culture and antibiotic therapy are mandatory although UTI treatment is becoming more challenging due to increasing resistance to routinely applied antibiotics. The use of an intrarenal urine culture and stone culture is recommended to adapt antibiotic therapy in case of postoperative infectious complications. Measurements of temperature and pressure during RIRS are vital for ensuring patient safety and optimizing surgical outcomes although techniques of measurements and methods for data analysis are still to be refined. Ureteral stents were improved by the development of new biomaterials, new coatings, and new stent designs. Topics of current research are the development of drug eluting and bioresorbable stents. Complications of endoscopic treatment: PCNL is considered the most invasive surgical option. Fever and sepsis were observed in 11 and 0.5% and need for transfusion and embolization for bleeding in 7 and 0.4%. Major complications, as colonic, splenic, liver, gall bladder and bowel injuries are quite rare but are associated with significant morbidity. Ureteroscopy causes less complications, although some of them can be severe. They depend on high pressure in the urinary tract (sepsis or renal bleeding) or application of excessive force to the urinary tract (ureteral avulsion or stricture). Diagnostic work up:  Genetic testing consents the diagnosis of monogenetic conditions causing stones. It should be carried out in children and in selected adults. In adults, monogenetic diseases can be diagnosed by systematic genetic testing in no more than 4%, when cystinuria, APRT deficiency, and xanthinuria are excluded. A reliable stone analysis by infrared spectroscopy or X-ray diffraction is mandatory and should be associated to examination of the stone under a stereomicroscope. The analysis of digital images of stones by deep convolutional neural networks in dry laboratory or during endoscopic examination could allow the classification of stones based on their color and texture. Scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) is another fundamental research tool for the study of kidney stones. The combination of metagenomic analysis using Next Generation Sequencing (NGS) techniques and the enhanced quantitative urine culture (EQUC) protocol can be used to evaluate the urobiome of renal stone formers. Twenty-four hour urine analysis has a place during patient evaluation together with repeated measurements of urinary pH with a digital pH meter. Urinary supersaturation is the most comprehensive physicochemical risk factor employed in urolithiasis research. Urinary macromolecules can act as both promoters or inhibitors of stone formation depending on the chemical composition of urine in which they are operating. At the moment, there are no clinical applications of macromolecules in stone management or prophylaxis. Patients should be evaluated for the association with systemic pathologies.

PROPHYLAXIS

Personalized medicine and public health interventions are complementary to prevent stone recurrence. Personalized medicine addresses a small part of stone patients with a high risk of recurrence and systemic complications requiring specific dietary and pharmacological treatment to prevent stone recurrence and complications of associated systemic diseases. The more numerous subjects who form one or a few stones during their entire lifespan should be treated by modifications of diet and lifestyle. Primary prevention by public health interventions is advisable to reduce prevalence of stones in the general population. Renal stone formers at "high-risk" for recurrence need early diagnosis to start specific treatment. Stone analysis allows the identification of most "high-risk" patients forming non-calcium stones: infection stones (struvite), uric acid and urates, cystine and other rare stones (dihydroxyadenine, xanthine). Patients at "high-risk" forming calcium stones require a more difficult diagnosis by clinical and laboratory evaluation. Particularly, patients with cystinuria and primary hyperoxaluria should be actively searched.

FUTURE RESEARCH

Application of Artificial Intelligence are promising for automated identification of ureteral stones on CT imaging, prediction of stone composition and 24-hour urinary risk factors by demographics and clinical parameters, assessment of stone composition by evaluation of endoscopic images and prediction of outcomes of stone treatments. The synergy between urologists, nephrologists, and scientists in basic kidney stone research will enhance the depth and breadth of investigations, leading to a more comprehensive understanding of kidney stone formation.

Mini Endoscopic Combined Intra-Renal Surgery (MiniECIRS) with endoview puncture in A 12 month boy. A safe but challenging procedure

INTRODUCTION

Associating minipercutaneous nephrolithotomy and retrograde flexible ureteroscopy (fURS) is called Mini Endoscopic Combined Intra-Renal Surgery (miniECIRS). It's a safe and efficient technique, also in children.

MATERIAL AND METHODS

The video describes miniECIRS in a 12 month-old boy with an infectious pelvic left stone (16 mm) and multiple caliceal stones. The UAS used was a 10FR and the percutaneous access was a 14Fr with Clear-Petra® sheath.

RESULTS

The operative time was 180 min and blood losses were virtually absent. There were no intra- or post-operative complications and the patient was discharged at the 5th day. After 1 month, double J was removed having a stone free status.

CONCLUSIONS

MiniECIRS with endoview puncture is a safe and efficient technique when performed by experienced hands. Therefore, it is an alternative to consider for the treatment of complex lithiasis in the pediatric population.

Antegrade flexible ureteroscopy-assisted percutaneous nephrolithotomy for staghorn calculi: a prospective randomized controlled study

The aim is to compare the efficacy and safety between single percutaneous nephrolithotomy (sPNL) and antegrade flexible ureteroscopy-assisted percutaneous nephrolithotomy (aPNL) for the treatment of staghorn calculi. A prospective randomized controlled study was conducted at the Second Hospital of Tianjin Medical University. A total of 160 eligible patients were included, with 81 in the sPNL group and 79 in the aPNL group. The study first compared the overall differences between sPNL and aPNL. Then, the patients were divided into two subgroups: Group 1 (with less than 5 stone branches) and Group 2 (with 5 or more stone branches), and the differences between the two subgroups were further analyzed. The results showed that aPNL had a higher stone-free rate (SFR) and required fewer percutaneous tracts, with a shorter operation time compared to sPNL (P < 0.05). Moreover, aPNL significantly reduced the need for staged surgery, particularly in patients with 5 or more stone branches. Moreover, there were no significant differences in the changes of hemoglobin levels and the need for blood transfusions between the sPNL and aPNL groups, and the incidence of multiple tracts was lower in the aPNL group. The two groups showed comparable rates of perioperative complications. We concluded that aPNL resulted in a higher SFR for staghorn calculi, and required fewer multiple percutaneous tracts, reduced the need for staged surgery, and had a shorter operative time than PNL alone, especially for patients with 5 or more stone branches. Furthermore, aPNL did not increase the incidence of surgical complications.

Endoscopic combined intrarenal surgery composed of micro-perc and retrograde intrarenal surgery in the treatment of complex kidney stones in children

OBJECTIVE

This research aims to explore the efficiency and safety of endoscopic combined intrarenal surgery (Micro-ECIRS) composed of micro-percutaneous nephrolithotomy (Micro-perc) and retrograde intrarenal surgery (RIRS) in the Galdakao-modified supine Valdivia (GMSV) position for a single session for the treatment of complex nephrolithiasis in children.

MATERIALS AND METHODS

This study retrospectively reviewed patients aged < 18 years who underwent Micro-ECIRS in the GMSV position for renal stones larger than 2 cm under ultrasound guidance between August 2020 to May 2022 at our institution.

RESULTS

A total of 13 patients (8 males and 5 females) received Micro-ECIRS for renal stones under ultrasound guidancewhile adopting the GMSV position. The average stone size was 2.7 cm (range: 2.1-3.7 cm). Among them, 6 patients had left kidney stones, 5 patients had right kidney stones, and 2 patients had bilateral kidney stones. The mean operative time was 70.5 min (range: 54-93 min). The mean hospital stay was 6.4 days (range: 4-9 days). The mean hemoglobin decrease was 8.2 g/L (range: 5.1-12.4 g/L). The total number of kidneys that had complete stone clearance was 8 kidneys at 48 h postoperatively, 11 kidneys at 2 weeks postoperatively, and 14 kidneys at 1 month postoperatively.

CONCLUSION

Our results demonstrate that Micro-ECIRS while patients are in the GMSV position is a safe and effective method for the treatment of complex children nephrolithiasis. However, all children made three hospital visits and received anesthesia three times. Further research is needed to confirm these findings.

Comparison of endoscopic versus CT assessment of stone-free status after percutaneous nephrolithotomy (PCNL)

This study is aimed to determine whether postoperative low dose computed tomography (LDCT) imaging is necessary after percutaneous nephrolithotomy (PCNL), or the surgeon's intraoperative assessment of residual fragments (RF) is sufficient and avoidance of postoperative imaging with reduction of radiation exposure can be achieved. Data of all 610 patients who underwent PCNL in prone position in our institution from February 2009 to September 2020 was collected. Parameters such as age, gender, BMI, ASA-Classification, stone related parameters and the surgeon's assessment of stone-free status were analyzed. The LDCT performed postoperatively was compared to the intraoperative assessment of the surgeon regarding RF. The mean age of patients was 52.82 years; the mean BMI was 28.18 kg/m2. In 418 cases, the surgeon made a clear statement about the presence of RF and postoperative LDCT was carried out. The discrepancy between the two methods (surgeon´s assessment vs. LDCT) was significant at p < 0.0001. The sensitivity, specificity, positive and negative predictive value of the surgeon when assessing RF were 24.05%, 99.45%, 98.28% and 50%. Stone free rate (SFR) after primary PCNL was 45.57%. The overall SFR at discharge was 96.23%. Although the surgeon´s assessment of RF was reliable, postoperative LDCT imaging should still be performed if endoscopic stone clearance is suspected due to the high false negative rate and the low negative predictive value. The optimal timing of postoperative imaging following PCNL remains unclear.

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.

Cystine Stones: Developments in Minimally Invasive Surgery and Their Impact on Morbidity and Stone Clearance

Cystinuria is a rare genetic condition that is responsible for cystine stones. Besides stone recurrence, patients with cystine stones have reduced health-related quality of life, increased rates of chronic kidney disease and hypertension. Although lifestyle measures, medical therapy and close follow up are essential to reduce and monitor cystine stone recurrences, surgical intervention is frequently needed for most cystinuria patients. Shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and active surveillance all have a role, and technological advances in endourology are vital in achieving a stone-free status and to prevent recurrences. The complexity of managing cystine stones necessitates a multidisciplinary team discussion, patient involvement and an individualised approach in a specialist centre for optimum management. Thulium fibre laser and virtual reality may have an increasing role in the future of cystine stone management.

Analysis of stone-free rates and residual fragment sizes following standard percutaneous nephrolithotomy: mistakes in the treatment of non-opaque kidney stones

Our presented study aimed to evaluate the possible effects of stone opacity, on both the success of percutaneous nephrolithotomy and the sizes of residual fragments following the procedure. Medical records of patients undergoing PCNL treatment for kidney stones at our clinic between July 2014 and May 2022 were evaluated in a retrospective manner. A total sample size of 304 patients with the required criteria was included. Patients were divided into two groups based on the radiopacity status of the stones assessed in the kidney-ureter-bladder graphy (KUB) [Group O (n = 211): opaque, Group N (n = 93): non-opaque)]. Demographic data, laboratory results, and surgical follow-up information were comparatively evaluated between groups. The mean age and percentage of female patients were higher in Group N (45.2 vs. 25,1%; p < 0.001). Also, patients in this group were associated with more comorbidities. No significant difference was present regarding stones' laterality, size, surface area, and localization. Cases in the Group N group demonstrated higher median hemoglobin reduction [1.7 (IQR = 1.2-2.5) vs. 2 (IQR = 1.6-2.6); p = 0.047]. The stone-free rates in Group O patients were higher (67.8% vs. 53.8%; p = 0.014). The size of the residual fragments was meaningfully larger in Group N cases [8 (IQR = 7-13) vs. 10 (IQR = 8-16); p = 0.032]. Finally, no significant difference was observed between the groups regarding both minor (as grade 3a and below) and major (grade 3b and above) assessed by the Modified Clavien-Dindo Classification. Our data show that treatment of patients with so-called non-opaque kidney stones by PCNL results in low SFR and larger residual fragments, which is due to a variety of errors that should be avoided by appropriate measures.

Hydrostatic pressure of the renal pelvis as a radiation-free alternative to fluoroscopic nephrostogram following percutaneous nephrolithotomy

Background

We evaluated the hydrostatic pressure of the renal pelvis (RPP) as a radiation-free alternative to fluoroscopic nephrostogram to assess ureteral patency after percutaneous nephrolithotomy (PCNL).

Methods

Retrospective non-inferiority study analyzing 248 PCNL-patients (86 female (35%) and 162 males (65%)) between 2007 and 2015. Postoperatively, RPP was measured using a central venous pressure manometer in cmH2O. The primary endpoint was to assess RPP depending on the patency of the ureter and the nephrostomy tube removal. Secondary, the upper limit of normal RPP of $$\le$$ ≤ 20 cmH2O was assessed as an indicator of an unobstructed patency.

Results

The median procedure duration was 141 min (112–171.5) with a stone free rate of 82% (n = 202). RPP was significantly higher in patients with obstructive nephrostogram with 25.0 mmH2O (21.0–32.0) versus 20.0 mmH2O (16.0–24.0; p < 0.001). The pressure was lower in successful nephrostomy removal with 18 cmH2O (15–21) versus 23 cmH2O (20–29) in the leakage group (p < 0.001). The analysis of a cut-off of $$\le$$ ≤ 20 cmH2O showed a sensitivity of 76.9% (95% CI [60.7%; 88.9%]) and a specificity of 61.5% (95% CI [54.6%; 68.2%]). The negative predictive value was 93.4% (95% CI: [87.9%; 97.0%]) and the positive predictive value 27.3% (95% CI [19.2%; 36.6%]). The accuracy of the model showed an AUC = 0.795 (95% CI [0.668; 0.862]).

Conclusion

The hydrostatic RPP seems to allow a bedside evaluation of ureteral patency after PCNL.

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.

Validation of the Trifecta Scoring Metric in Vacuum-Assisted Mini-Percutaneous Nephrolithotomy: A Single-Center Experience

Background: Scoring metrics to assess and compare outcomes of percutaneous nephrolithotomy (PCNL) are needed. We aim to evaluate prevalence and predictors of trifecta in a cohort of patients treated with vacuum-assisted mini-percutaneous nephrolithotomy (vmPCNL) for kidney stones. Methods: Data from 287 participants who underwent vmPCNL were analysed. Patients’ and stones’ characteristics as well as operative data were collected. Stone-free was defined as no residual stones. The modified Clavien classification was used to score postoperative complications. Trifecta was defined as stone-free status without complications after a single session and no auxiliary procedures. Descriptive statistics and logistic regression models tested the association between predictors and trifecta outcome. Results: After vmPCNL, 219 (76.3%) patients were stone-free, and 81 (28.2%) had postoperative complications (any Clavien). Of 287, 170 (59.2%) patients achieved trifecta criteria. Patients who achieved trifecta status had smaller stone volume (p < 0.001), a higher rate of single stones (p < 0.001), shorter operative time (p < 0.01), and a higher rate of single percutaneous tract (p < 0.01) than −trifecta patients. Trifecta status decreased with the number of calyces involved, being 77.1%, 18.8%, and 4.1% in patients with 1, 2, or 3 calyces with stones, respectively (p < 0.001). Multivariable logistic regression analysis showed that stone volume (OR 1.1, p = 0.02) and multiple calyces being involved (OR 2.8 and OR 4.3 for two- and three-calyceal groups, respectively, all p < 0.01) were independent unfavourable risk factors for trifecta after accounting for age, BMI, gender, operative time, and number of access tracts. Conclusions: Trifecta status was achieved in 6 out of 10 patients after vmPCNL. Stone distribution in multiple calyceal groups and stone volume were independent unfavourable risk factors for trifecta.

Comparison of mini endoscopic combined intrarenal surgery and multitract minimally invasive percutaneous nephrolithotomy specifically for kidney staghorn stones: a single-centre experience

BACKGROUND

Staghorn stones require surgical treatment to prevent serious complications. Multitract percutaneous nephrolithotomy (PNL) causes great renal parenchymal injury and blood loss. One-stage endoscopic combined intrarenal surgery (ECIRS) entails the combined use of antegrade nephroscope and retrograde flexible ureteroscope to clear the staghorn stone, which may overcome the limitations of multitract PNL. We aimed to compare the perioperative outcomes of mini ECIRS and multitract minimally invasive PNL in staghorn stone management.

METHODS

This was a retrospective single-center study of patients with staghorn stones who underwent ECIRS (n = 17) or multitract minimally invasive PNL (n = 17) between January 2018 and September 2021.

RESULTS

There was a significant between-group difference with respect to Guy's stone score. Stone size, stone burden (ECIRS group, 21.41 cm3; multitract minimally invasive PNL group, 20.88 cm3 [P = 0.94]), and degree of hydronephrosis were comparable in the two groups. There was no significant between-group difference with respect to one-step or final stone-free rates. The mean operative time was also not significantly different between the groups (ECIRS group, 140 min; multitract minimally invasive PNL group, 183 min [P = 0.63]). ECIRS was associated with significantly lesser postoperative pain (visual analog scale; ECIRS group: 0; multitract minimally invasive PNL group: 2.7 [P < 0.001]). Hemoglobin loss, postoperative blood transfusion rate, complications, and length of hospital stay were comparable in the two groups.

CONCLUSION

Both mini ECIRS and multitract minimally invasive PNL were effective and safe for the management of renal staghorn stones with comparable operation time and stone-free rate, and complications. ECIRS was associated with less severe postoperative pain.