Papillary vs Nonpapillary Puncture in Percutaneous Nephrolithotomy: A Prospective Randomized Trial

Does success in percutaneous nephrolithotomy depend only on stone size? Analysis of the predictive capacity for success and complications of the current nephrolithometry scoring systems and their relationship with the stone surface

OBJECTIVE

To analyze the predictive capacity of the nephrolithometry scoring systems (GSS, STONE, CROES and S-ReSC) and stone surface regarding success and complications following percutaneous nephrolithotomy (PCNL).

METHODS

We studied 392 patients who had undergone PCNL in our center. Only patients with a non-contrast CT (n = 240) were finally included for analysis. The predictive capacities for success and complications of the different scoring systems were evaluated using ROC curves and their area under the curve (AUC).

RESULTS

Regarding success, the S-ReSC system had the highest predictive capacity with an AUC of 0.681 (95% CI 0.610-0.751), followed by the CROES with 0.667 (95% CI 0.595-0.738), the STONE with 0.654 (95% CI 0.579-0.728) and finally the GSS with 0.626 (95% CI 0.555-0.698). The stone surface as a single variable had an AUC of 0.641 (95% CI 0.565-0.718). As for complications, the S-ReSC had the highest AUC with 0.664 (95% CI 0.57-0.758), followed by STONE with 0.663 (95% CI 0.572-0.755), GSS with 0.626 (95% CI 0.555).-0.698) and CROES with 0.614 (95% CI 0.518-0.7). The stone surface alone had an AUC of 0.616 (95% CI 0.522-0.715).

CONCLUSION

The nephrolithometry scales analyzed show a moderate predictive capacity for success and complications in patients undergoing PCNL in our center. Moreover, stone surface as an independent variable demonstrates moderate predictive capacity for both outcomes.

Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective

This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery.

Methods

A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above.

Results

The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples.

Conclusion

This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

Nonpapillary Prone Endoscopic Combined Intrarenal Surgery (ECIRS): Five-Year Experience and Outcomes from a High-Volume Center

Endoscopic combined intrarenal surgery (ECIRS) provides simultaneous retrograde and percutaneous access to the upper urinary tract. The purpose of this study is to present revised data, tips and tricks, and technique modifications arising from our five-year experience with ECIRS. The data of 62 patients who underwent nonpapillary prone ECIRS from January 2019 to November 2023 were prospectively collected. All cases were performed in the prone position. Inclusion criteria were complex stone cases with stones in multiple calyces requiring either multiple accesses or multiple sessions to achieve stone-free status. Patients' mean age was 54.4 ± 12.39 years, while the mean stone size was 39.03 ± 13.93 mm. The mean operative time was 51.23 ± 17.75 min. Primary and final stone-free rates were 83.8% and 90.3%, respectively. In total, nine patients presented with postoperative complications, which were all Grade II ones. The holmium-YAG laser type during retrograde lithotripsy was associated with significantly shorter operative times compared to the thulium fiber laser. Nonpapillary prone ECIRS is a feasible, safe, and efficient approach for patients with specific stone and anatomy characteristics. The implementation of more, higher-evidence studies is of utmost importance so that safer conclusions can be drawn.

Percutaneous nephrolithotomy non-papillary puncture trends. A review of the literature

Percutaneous nephrolithotomy (PCNL) is the gold standard of treatment for large renal calculi. Papillary puncture is the mainstay of treatment for large renal calculi, but the non-papillary has been introduced and gained some interest. The aim of this study is the investigation of trends of non-papillary access for PCNL over the years. A review of the literature took place and 13 publications were included in the study. Two experimental studies investigating the feasibility of non-papillary access were found. Five cohort prospective and 2 retrospective studies for non-papillary access and 4 comparative studies between papillary and non-papillary access were included. Non papillary access is a technique that has been proved as a safe and efficient solution that keeps up with the latest endoscopic trends. A wider use of this method could be expected in the future.

Percutaneous antegrade management of large proximal ureteral stones using non-papillary puncture

Objective

To evaluate the feasibility and the safety of medial non-papillary percutaneous nephrolithotomy (npPCNL) for the management of large proximal ureteral stones.

Methods

We evaluated prospectively collected data of 37 patients with large proximal ureteral stones more than 1.5 cm in diameter treated by prone npPCNL. Depending on stone size, in-toto stone removal or lithotripsy using the Lithoclast® Trilogy (EMS Medical, Nyon, Switzerland) was performed. Perioperative parameters including operative time (from start of puncture to the skin suturing), stone extraction time (from the first insertion of the nephroscope to the extraction of all stone fragments), and the stone-free rate were evaluated.

Results

Twenty-one males and 16 females underwent npPCNL for the management of large upper ureteral calculi. The median age and stone size of treated patients were 58 (interquartile range [IQR]: 51-69) years and 19.3 (IQR: 18.0-22.0) mm, respectively. The median operative time and stone extraction time were 25 (IQR: 21-29) min and 8 (IQR: 7-10) min, respectively. One case (2.7%) of postoperative bleeding and two cases (5.4%) of prolonged fever were managed conservatively. The stone-free rate at a 1-month follow-up was 94.6%.

Conclusion

The npPCNL provides a straight route to the ureteropelvic junction and proximal ureter. Approaching from a dilated portion of the ureter under low irrigation pressure with larger diameter instruments results in effective and safe stone extraction within a few minutes.

Superselective renal arterial embolization for severe postpercutaneous nephrolithotomy haemorrhage: clinical characteristics and risk factors for initial failure

OBJECTIVE

To identify the clinical characteristics of patients who underwent superselective renal arterial embolization (SRAE) after percutaneous nephrolithotomy (PCNL) and to explore the risk factors for failed initial SRAE after PCNL.

MATERIALS AND METHODS

Patients who underwent SRAE for severe haemorrhage following PCNL between January 2014 and December 2020 were included in the study. The clinical data of those patients and the parameters and characteristics of the perioperative PCNL and SRAE procedures were collected and analysed.

RESULTS

A total of 243 patients were included in this study. A total of 139 patients (57.2%) had a pseudoaneurysm, 25 (10.3%) had an arteriovenous fistula, 50 (20.6%) patients had both a pseudoaneurysm and an arteriovenous fistula, and 29 (11.9%) had an arterial laceration. In 177 patients with single percutaneous access, 125 (70.6%) patients exhibited nontract haemorrhage, and 55 (31.1%) patients exhibited multiple bleeding sites. In 66 patients with multiple percutaneous access, 44 (66.7%) patients exhibited nontract haemorrhage, and 32 (48.5%) patients exhibited multiple bleeding sites. The decrease in Hb before SRAE was 41.4 ± 19.8 g/L. The mean time between PCNL surgery and initial SRAE was 6.4 ± 4.9 days. Serum creatinine was increased after the SRAE procedure. Initial SRAE was successful in 229 (94.2%) patients and failed in 14 (5.8%) patients. Multivariate regression demonstrated that hydronephrosis < 20 mm, total ultrasonographic guidance, solitary kidney, previous ipsilateral renal surgery, PCNL duration > 90 min and multiple bleeding sites were potential risk factors for initial embolization failure.

CONCLUSION

Percutaneous access was not the most important reason for post-PCNL severe haemorrhage. SRAE is effective for the treatment of severe haemorrhage following PCNL; however, several factors have an impact on the success of initial SRAE. Additionally, the SRAE procedure may affect renal function.

The effect of percutaneous tract dilation technique on renal parenchymal trauma: An experimental in vivo study on a porcine model

Purpose

The purpose of this study was to evaluate renal parenchymal trauma of two-step dilation compared to the conventional Amplatz gradual dilation during percutaneous nephrolithotomy on a porcine model.

Materials and Methods

A nonpapillary percutaneous access tract was established under fluoroscopic guidance in both kidneys of four female pigs. On the right kidney of each pig, gradual dilation was performed using an Amplatz dilator set with a gradual dilation to 30 Fr, whereas on the left, a two-step dilation was utilized using only 16 Fr and 30 Fr dilators. Two of the animals were euthanized immediately after the procedure and the remaining two 1 month later. The pigs that were kept alive underwent a contrast-enhanced computed tomography immediately, 15, and 30 days postoperatively. A dimercaptosuccinic acid (DMSA) scintigraphy and single-photon emission computed tomography-computed tomography (CT) were also performed after the last CT and afterward, the pigs were sacrificed. All kidneys were harvested for pathohistological examination.

Results

The follow-up radiologic imaging showed similar parenchymal damage caused by the compared dilation techniques and an expected reduction in scar size in the later scans. No scar was identified by DMSA in any kidney. Gross and microscopic examinations conducted both on the kidneys that were harvested immediately after the procedure and the ones from the animals that were left to heal, revealed no significant differences in tissue damage, grade of fibrosis, or inflammation depending on the dilation method.

Conclusions

Our study showed no inferior outcomes caused by two-step dilation compared to gradual dilation regarding renal parenchymal damage following a nonpapillary puncture. In fact, postoperative imaging findings suggested a trend toward better healing and less scar tissue when the two-step method was used.

Advances in percutaneous renal puncture: a comprehensive review of the literature

PURPOSE OF REVIEW

Percutaneous nephrolithotomy (PCNL) constitutes the gold standard procedure for patients suffering from more than 2 cm renal stones. The puncture is a very critical step of PCNL, affecting manoeuvrability of the nephroscope, possibility to remove stone fragments, risk of bleeding and radiation exposure. The aim of the current review was to discuss the advances in percutaneous renal puncture.

RECENT FINDINGS

Following technological evolution in medicine, there was a consistent development in the puncture techniques, aiming at the improvement of its efficacy and safety. The use of specific agents can improve ultrasonic guidance, making the challenging step of gaining access to the kidney easier for the experienced surgeon and more accessible for the resident urologist. Future developments in the electromagnetic and three-dimensional (3D) technology may establish a high level of accuracy with decreased rates of related complications, even in the hands of beginners.

SUMMARY

The advances in percutaneous puncture can lead to improved safety and accuracy of this procedure decreasing the radiation exposure and the complication rate.

Non-papillary prone percutaneous nephrolithotomy for renal abnormalities: single-institution experience

PURPOSE

To evaluate the effectiveness and safety of non-papillary prone PCNL for the treatment of patients with renal abnormalities.

METHODS

An observational retrospective cohort study including PCNL cases of patients with renal abnormalities was performed. The following inclusion criteria were applied: renal stones > 1.5 cm with maximal diameter, anatomical malformations of affected kidney (malrotated kidneys, horseshoe kidneys and kidneys with complete duplicated systems, medullary sponge kidney), patients treated with standard (30Fr) PCNL or mini-PCNL (22Fr). The lithotripsy was performed using the Lithoclast Master or the Lithoclast^® Trilogy (EMS Medical, Nyon, Switzerland).

RESULTS

Overall, 57 patients, 35 males, and 22 females with any renal malformation underwent non-papillary prone PCNL. Our study included 25 patients with horseshoe kidneys, 21 with malrotated kidneys, 9 with kidneys with duplicated pelvicalyceal systems and 2 with medullary sponge kidneys. The mean cumulative stone size was 36 ± 1.4 mm and most of the stones were in the lower calyceal group (36.9%) and in the pelvis (27.2%). The stone-free rate (SFR) was 84.2% and the mean hospitalization time was 2.7 ± 0.7 days. In total, postoperative complications were developed in six patients (10.5%), half of them presenting fever and the other half requiring blood transfusion (Grade II).

CONCLUSION

The PCNL is the method of choice for treating large stones in anomalous kidneys. The generally accepted panacea that only a papillary puncture is safe is questioned by our results. Based on our experience, a non-papillary puncture proved to be a safe and effective procedure.

Comparing the outcomes of papillary and non-papillary access in percutaneous nephrolithotomy

BACKGROUND

Some publications have recently been released on the safety of non-papillary access (NPA) in percutaneous nephrolithotomy (PCNL) by a Greek group. The purpose of this study was to prospectively examine the outcome of NPA during two years in a referral center.

METHODS

This prospective cohort study was conducted on PCNL operations performed from January 2020 to April 2022 in Labbafinejad Hospital. In cases in which obtaining papillary access (PA) was not obtainable after several attempts and NPA was obtained, or in cases in whom after entry to the pyelocalyceal system, a NPA was observed, the cases were categorized in the NPA group (n = 67). The control group (PA) was composed of patients who had undergone PCNL with papillary access with similar stone bulk (n = 67). The primary endpoints of interest were hemoglobin drop and transfusion frequency. The secondary endpoint included: stone free rate (SFR), operation duration, and complications.

RESULTS

A total of 134 patients were enrolled during the study period which included 33 female patients (25%). The mean ± SD age of patients was 49.6 ± 13.2 years. The frequency of transfusion and residual stones was not different between NPA and PA groups: 6 (9%) versus 8 (11%), P = 0.29; and 16 (24%) versus 12 (18%), P = 0.26. Likewise, the operation time (87.6 ± 25.8 versus 90.2 ± 22.6 min, P = 0.45), and the frequency of intraoperative and postoperative complications were not different between the NPA and PA groups.

CONCLUSION

The results of this prospective study did not reveal a higher frequency of residual stones, transfusion, or complications in the NPA group. Nevertheless, our study is not powered enough to reveal complications of low frequency including delayed bleeding.

Position-related anesthesiologic considerations and surgical outcomes of prone percutaneous nephrolithotomy: a review of the current literature

The aim of the current study was to perform a critical review of existing literature and report the potential morbidity of patient positioning during urological surgeries as well as evaluate the surgical outcomes and anesthesiologic benefits and risks of prone percutaneous nephrolithotomy (PCNL). A narrative review of the current literature has been performed. Articles related to position-related injuries and complications under general anesthesia in prone positions were selected, studied, and considered for the current review. We found that under general anesthesia, the prone position improved the oxygenation of patients and increased the elimination of carbon dioxide. A potential risk for position-related anesthesiologic side effects was reported for longer spine surgeries in a prone position. The injuries and position-related side effects were extremely rare following prone PCNL since the mean duration of the procedure was significantly shorter than that of spine surgery. In conclusion, the prone PCNL remains the most often utilized and preferred approach globally with well-established success and complication rates. Clinical outcomes of prone PCNL do not demonstrate an increased rate of anesthesiologic complications compared to the supine approach. Standardization of turnover of the position, and reduction of the operative time warrant a faster and complication-free recovery.

Hands on wet lab and live surgery training in PCNL: Any impact to surgical skills of attending surgeons?

Objectives: The clinical value and efficiency of hands-on training courses in percutaneous nephrolithotomy (PCNL) remains undocumented. During the last 9 years, a two-day international intensive hands-on training course in fluoroscopic guided prone PCNL is taking place in our department on a monthly basis. Course includes wet lab training in the porcine model and live surgery training. In this work we report the outcomes of a survey send to course participants questioning the impact of the course to their clinical practice.Materials and methods: A survey consisting of 26 questions was distributed online to a total of 91 trainees that had completed the course. Comparison of pre and post course surgical practices was performed using the "N-1" Chi-squared test.Results: A total of 64 trainees responded to our online survey with 55.6% and 41.3% reporting a modest or major impact to their practice accordingly. Notable changes in puncture and dilation technique were evidenced while a uniform reduction in puncture and operative times was documented. 79.4% responded that the course increased the safety of their procedure, 73% that it reduced operating times, 39.7% that increased their stone free rates, 23.8% that reduced their complications and 23.8% that induced to change their instrumentation with respect of that they were using in the past. Subgroup analysis including only well experienced surgeons revealed a similar impact to their practice.Conclusions: In the proper setting, an intensive hands-on PCNL course can have a significant impact on attending physicians. Participation to such events even for experienced surgeons should be encouraged.

Risk Factors for Intra-operative Bleeding in Percutaneous Nephrolithotomy in an Academic Center: A Retrospective Study

Background

Percutaneous nephrolithotomy (PNL) is the treatment of choice for renal stones as a safe, effective, and minimally invasive method. However, bleeding remains a major concern in the procedure.

Objectives

This study aimed to investigate the risk factors of bleeding in PNL.

Methods

This retrospective descriptive cross-sectional study was conducted in the Urology department of Razi hospital. The data of patients with urinary calculi staghorn type who underwent PNL in a prone position under general anesthesia were recorded. A checklist including patients' demographics, surgical characteristics, and outcomes was filled out for each patient.

Results

The data from 151 complete files were gathered. The mean age of the cases was 47.89 ± 12.41 years. The mean hemoglobin (Hb) drop was 1.92 ± 1.56 mg/dL. At least 1 mg/dL Hb drop was observed in all cases. The highest Hb drop was 3 mg/dL.). There was no significant relationship between stone bulk, age, BMI, GFR, surgery duration, and the number of tracts, and Hb drop during PNL (P > 0.05). But there was a positive correlation between Urinary Tract Infection (UTI) history (P = 0.01) and transfusion (P = 0.0001) and Hb drop during PNL. Also, the history of open kidney surgery (P = 0.031), nephrostomy insertion (P = 0.003), and extracorporeal shock wave lithotripsy therapy (ESWL) (P = 0.041) were correlated with the increased risk of Hb drop.

Conclusions

Urinary tract infection, history of open surgery, nephrostomy implantation, and ESWL were significantly associated with more bleeding in PNL.

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

Background: Managing complex and large renal stones with percutaneous nephrolithotomy (PCNL) is difficult because of the likelihood of residual stones and multiple access. Endoscopic combined intrarenal surgery (ECIRS) is introduced as an improvement to the procedure to manage stones in one session. The objective of this systematic review and meta-analysis is to compare the efficacy and safety between ECIRS and PCNL for treating large and complex renal stones. Materials and Methods: We conducted a systematic review in the Embase, Scopus, and MEDLINE databases based on the 2020 Preferred Reporting Items for Systematic Review and Meta-Analyses guideline. Eligible studies comprised both randomized and nonrandomized studies comparing ECIRS and PCNL. Results: A total of five nonrandomized studies and one randomized controlled trial were included. The analysis was divided into two subgroups based on the PCNL type, a conventional PCNL (cPCNL) and a mini-PCNL (mPCNL). The one-step stone-free rate (SFR) of ECIRS were significantly higher compared with both the cPCNL (odds ratio [OR] 5.14, 95% confidence interval [CI] 2.54 to 10.4, p < 0.001) and mPCNL (OR 4.27, 95% CI 2.57-7.1, p < 0.001). There were no significant differences in mean operative time and hemoglobin drop between both groups (p > 0.05). The use of auxiliary procedures was significantly higher in both PCNL groups compared with the ECIRS group (OR 0.19, 95% CI 0.13-0.30, p < 0.001). The overall complication rate of ECIRS was lower compared with PCNL (OR 0.43, 95% CI 0.21-0.85, p = 0.02), especially urosepsis, in which the incidence was lower compared with cPCNL (OR 0.14, 95% CI 0.02-0.78, p = 0.02), but not mPCNL (p > 0.05). Conclusion: ECIRS is an effective and safe treatment particularly for large and complex nephrolithiasis, with significantly higher one-step SFR, a lower necessity for auxiliary procedures, and a lower complication rate compared with PCNL.

Presence of a Novel Anatomical Structure May Cause Bleeding When Using the Calyx Access in Mini-Percutaneous Nephrolithotomy

Background

Fused renal pyramid (FRP) is a kidney anatomical structure which was first identified by us. The vascular anatomy of FRP exhibits different from that of the normal renal pyramid (NRP), manifested by the distribution of the ectopic interlobar arteries in FRP. In this study, we analyzed the effect of FRPs on bleeding when using calyx access in mini-percutaneous nephrolithotomy (PCNL).

Patients and Methods

Overall, 633 patients who underwent ultrasound-guided single-tract mini-PCNL were divided into two groups according to the puncture method used: in group A, puncture was performed through the axial direction of the renal calyx, the line from the apex of the fornix to the center of the neck plane under B-mode ultrasound guidance; and in group B, Doppler ultrasound-guided axillary puncture through calyces corresponding to NRPs when the plane of renal column blood vessels on both sides was selected or calyx puncture through the hypovascular area of the FRPs. Relevant demographic and clinical data were retrospectively analyzed.

Results

The two groups exhibited similar baseline characteristics. No significant differences were found in hemoglobin reduction, puncture site, tract size, postoperative creatinine level, or stone-free rate between the two groups (P > 0.05). Blood transfusion and embolization rates in group B were significantly lower than those in group A (P = 0.03 and 0.045, respectively). No differences were found between the two groups in terms of persistent pain, hydrothorax, fever, subcapsular hematoma, and urosepsis (P > 0.05). The overall complication rate was not significantly different between the two groups (P = 0.505).

Conclusions

FRP is a non-negligible anatomical structure that may cause hemorrhage when using calyx access. Doppler ultrasound can identify ectopic blood vessels in FRPs to reduce bleeding during calyx access in mini-PCNL procedures.

Feasibility of contrast-enhanced ultrasound and flank position during percutaneous nephrolithotomy in patients with no apparent hydronephrosis: a randomized controlled trial

Purpose

To investigate the puncture accuracy and feasibility of contrast-enhanced ultrasound (CEUS) guided percutaneous nephrolithotomy (PCNL) in flank position for patients with no apparent hydronephrosis.

Methods

Between May 2018 and June 2020, 72 kidney stone patients with no or mild hydronephrosis were randomized into two groups: a CEUS-guided PCNL group and a conventional ultrasound (US)-guided group. Patients’ demographics and perioperative outcomes were compared, including the success rate of puncture via calyceal fornix, the success rate of a single-needle puncture, puncture time, operative time, postoperative hemoglobin loss, stone-free rate, incidence of complications and postoperative stay.

Results

The success rate of puncture via calyceal fornix for CEUS-guided group was significantly higher than that for conventional US-guided group (86.1 vs. 47.2%, p = 0.002). Patients performed with CEUS-guided PCNL required shorter renal puncture time than those guided with conventional US (36.5 s vs. 61.0 s, p < 0.001). The median postoperative hemoglobin loss in the CEUS-guided group was significantly lower than that in conventional US-guided group (2.5 vs. 14.5 g/L, p < 0.01). There was no statistically significant difference in the success rate of a single-needle puncture, operative time, stone-free rate, incidence of complications and postoperative stay between the two groups.

Conclusion

CEUS guidance facilitates identification of the renal calyx fornix, and benefits more precise renal puncture and less hemoglobin loss in PCNL. CEUS-guided PCNL in flank position is a feasible approach to the treatment of kidney stone patients with no apparent hydronephrosis.

Trial registration number: ChiCTR1800015417.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-03933-4.

Nonpapillary prone endoscopic combined intrarenal surgery: effectiveness, safety and tips, and tricks

PURPOSE

To evaluate the effectiveness and safety of nonpapillary prone endoscopic combined intrarenal surgery (ECIRS) and provide practical tips and tricks for the successful accomplishment of the procedure respecting the anatomical particularities.

MATERIAL AND METHODS

This study is an analysis of a prospectively collected database including all cases of ECIRS performed between January 2019 and December 2021 in a high-volume tertiary center. All patients underwent the procedure in prone-split leg position. A nonpapillary renal puncture was performed. The used access sheaths were 22Fr or 30Fr. Lithotripsy was performed anterogradely with a dual-energy lithotripter with incorporated suction and retrogradely with holmium Yttrium-Aluminum-Garnet laser.

RESULTS

A total of 33 patients were included. The initial stone-free rate (SFR) was 84.8% and the final SFR was 90.9%. The median stone size was 35 mm and 60% of patients had staghorn calculi. The prevalence of renal abnormalities was 21.3%, including 3 cases of horseshoe kidney, 2 cases of malrotation and 2 cases with complete duplicated systems. The median operative time was 47 min. The median hospital stay was 3 days and median hemoglobin loss was 1.2 gr/dL. Overall, the complication rate was 9.1%, all being Grade II complications (n = 2 fever and n = 1 transient bleeding).

CONCLUSIONS

Nonpapillary prone ECIRS is an effective and safe procedure. Standardization of the procedure is critical to achieve good outcomes. Patients who benefit the most are probably the ones where additional punctures can be avoided using this technique, namely patients with renal abnormalities, incrusted ureteral stents and staghorn stones.

Can Color Doppler Ultrasound Challenge the Paradigm in Percutaneous Nephrolithotomy?

OBJECTIVES

Compare color Doppler (Color) ultrasound-guided puncture to common type-B (Type-B) ultrasound-guided puncture in reducing the incidence of hemorrhagic complications of percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A total of 348 patients who received PCNL from September 2017 to December 2018 were divided into Color (231 cases) and Type-B groups (117 cases). The avascular area of the target fornix was pinpointed in the Color group while the middle of the target fornix was the default puncture point in the Type-B group. Tract bleeding, nephrostomy tract creation time, operation time, postoperative hemoglobin (Hb) values and serum creatinine (Scr) concentrations, and stone-free rates were analyzed.

RESULTS

Color Doppler imaging revealed that 35.1% of the cases in the Color group (81/231) had variable artery positioning in the target fornix. Tract bleeding and postoperative Hb reduction in the Color group were significantly lower than the Type-B group (10.8% vs 24.8%, P=0.0007, and 4.87±8.58 vs 7.70±8.90 g/L, P=0.0044, respectively). The postoperative hospitalization of the Color group was also shortened (8.3±5.9 vs 9.7±3.0 d, P<0.0001). Although working channel creation took longer in this group (4.2±0.3 vs 3.6±0.2 min, P<0.0001), there were no significant differences in the total operation time between the two groups (39.2±15.2 vs 36.4±16.5 min, P=0.1097) or postoperative Scr and stone-free rates.

CONCLUSION

Vascular variation of the fornix is very common. Consistent puncture of the avascular area of the target fornix significantly lowered tract bleeding and postoperative Hb decrease compared to traditional procedures. Color Doppler ultrasound-guided puncture is thus useful to reduce the incidence of severe hemorrhagic complications of PCNL.

Percutaneous puncture during PCNL: new perspective for the future with virtual imaging guidance

CONTEXT

Large and complex renal stones are usually treated with percutaneous nephrolithotomy (PCNL). One of the crucial steps in this procedure is the access to the collecting system with the percutaneous puncture and this maneuver leads to a risk of vascular and neighboring organs' injury. In the last years, the application of virtual image-guided surgery has gained wide diffusion even in this specific field.

OBJECTIVES

To provide a short overview of the most recent evidence on current applications of virtual imaging guidance for PCNL.

EVIDENCE ACQUISITION

A non-systematic review of the literature was performed. Medline, PubMed, the Cochrane Database and Embase were screened for studies regarding the use virtual imaging guidance for PCNL.

EVIDENCE SYNTHESIS

3D virtual navigation technology for PCNL was first used in urology with the purpose of surgical training and surgical planning; subsequently, the field of surgical navigation with different modalities (from cognitive to augmented reality or mixed reality) had been explored. Finally, anecdotal preliminary experiences explored the potential application of artificial intelligence guidance for percutaneous puncture.

CONCLUSION

Nowadays, many experiences proved the potential benefit of virtual guidance for surgical simulation and training. Focusing on surgery, this tool revealed to be useful both for surgical planning, allowed to achieve a better surgical performance, and for surgical navigation by using augmented reality and mixed reality systems aimed to assist the surgeon in real time during the intervention.

Technical aspects to maximize the hyperaccuracy three-dimensional (HA3D™) computed tomography reconstruction for kidney stones surgery: a pilot study

The aim of the current prospective pilot study was to describe a hyperaccuracy three-dimensional (HA3D^™) model reconstruction technique, specifically developed to maximize the visualization of the renal collecting system's anatomy, and its relationship with the stones, vessels and renal parenchyma, and to compare the HA3D^™ virtual models with the intraoperative findings. The image acquisition was performed using a CT scanner (Toshiba, Aquilion Prime) and included the unenhanced, arterial, venous and excretory phases. The DICOM format CT images were processed by MEDICS Srl ( www.medics3d.com , Turin, Italy). In total, study included three patients with renal stone scheduled for non-papillary prone percutaneous nephrolithotomy (PCNL). The median age and BMI were 51 (range 49-54) and 25.5 (range 25.0-32.7), respectively. The median stone size was 1170 mm² (range 830-1520) and median stone density was 1130 HU (range 600-1340). In all cases, the quality of the CT images acquired with our protocol was adequate to perform the HA3D^™ reconstruction. Median operative and puncture time were 39.4 (range 35.2-44.0) and 1.9 (range 1.8-2.1) mins, respectively. The success rate for the first attempt of the percutaneous puncture was 100%, and only one PCNL tract was sufficient to complete the surgery. All three patients were stone-free on the third postoperative day. A dedicated imaging acquisition protocol and a tailored 3D model reconstruction process specifically developed for kidney stones treatment allow obtaining HA3D^™ highly relevant models to greatly match intraoperative findings during PCNL with the potential of minimizing bleeding and organ injury complications.

Non papillary mini-percutaneous nephrolithotomy: early experience

PURPOSE

This study aims to evaluate the non-papillary puncture for mini-PCNL in terms of safety and efficacy.

METHODS

A total number of 32 patients were subjected to mini-PCNL by the performance of non-papillary punctures over 6 months. One-step track dilation to 22 Fr took place in all cases. An 18 Fr nephroscope (Slender, Karl Storz GmbH, Germany) and an ultrasound lithotripter (Lithoclast Master, EMS S.A, Switzerland) with 9.9 Fr probe was used. Demographics and perioperative data are prospectively collected from an institutional board-approved database and the presented data were retrospectively collected.

RESULTS

The average cumulative stone size was 23.53 ± 6.6 mm. Mean operative time was 44.6 ± 13.44 min and primary stone-free rate after PCNL was 96% and 85.7% for single and multiple access, respectively. Second access was performed in seven cases, all of which had multiple stones. Mean hemoglobin drop was 1.23 ± 0.88 gr/dL. The patients stayed 2.56 ± 0.98 days in the hospital. Overall complication rate was 9.37%, without encountering any severe bleeding complication.

CONCLUSION

Using non-papillary access for mini-PCNL did not result in significant blood loss and need for transfusions. The respective data were directly comparable to contemporary literature and the safety of mini-PCNL by a non-papillary approach could be advocated.

Complications and surgical results of stone-directed antegrade pyelography compared to the retrograde pyelographic access method in percutaneous nephrolithotomy using ‘bull’s eye’ technique: A randomized clinical trial

Objectives:

This study aimed to evaluate the differences in outcomes and complications in stone-directed antegrade pyelography using the ‘bull’s eye’ technique in patients with renal stones versus the conventional method of percutaneous nephrolithotomy (PCNL). Although conventional PCNL access using retrograde pyelography is useful, it is time-consuming and may cause postoperative discomfort. Herein, we report our experience in the application of this new technique.

Methods:

Between January 2017 and June 2018, 100 patients participated in this randomized clinical trial. Stone-directed antegrade pyelography using the ‘bull’s eye’ technique under fluoroscopic guidance was used for percutaneous access in the intervention group. The second group, consisting of those who had undergone conventional PCNL using retrograde pyelography and ‘bull’s eye’ technique in the same period, were considered as the controls. Pre- and postoperative laboratory examinations, surgical results and complications were recorded and compared between the two groups.

Results:

A single calyceal puncture in partial staghorn and staghorn stone patients was sufficient in 72.2% of the antegrade group and in 78.9% of the retrograde group ( p=0.69). The double-puncture technique was necessary for 71.9% of renal pelvis stones in the antegrade group and for 9.4% in the retrograde group ( p<0.001). The antegrade approach reduced the mean operative time and analgesic requirement significantly ( p<0.001). No statistically significant difference, however, was found between the two groups regarding stone migration to the ureter, radiation time and postoperative complications.

Conclusions:

The stone-directed antegrade approach using the ‘bull’s eye’ technique is a safe and accurate method in PCNL access in patients with radiopaque and semi-opaque renal stones.

Non-papillary percutaneous nephrolithotomy for treatment of staghorn stones

BACKGROUND

The aim of this study was to evaluate the non-papillary puncture for Percutaneous Nephrolithotomy (PCNL) for the treatment of staghorn stones in terms of safety and efficacy.

METHODS

Data of 53 patients undergoing PCNL for staghorn stones were retrospectively collected from January 2015 to December 2019. A non-papillary puncture was performed with a two- step track dilation technique up to 30Fr. A 26 Fr semirigid nephroscope and an ultrasonic lithotripter with integrated suction (Swiss Lithoclast master, EMS S.A, Nyon, Switzerland) were used for the treatment. Demographics and perioperative data were retrospectively gathered from an institutional board approved database.

RESULTS

The average stone size was 60.1±16.1 mm. Mean operative time was 54.57±14.83 minutes, while mean time using fluoroscopy was 2.67±1.02 minutes. Mean number of accesses was 1.2 (a total of 64 accesses). Flexible nephroscope was never used. Primary stone-free rate after PCNL was 81.1% (43 patients). Mean hemoglobin drop was 1.6±1.86 gr/dL. Overall patient stay was 3.94±0.82 days, while overall complication rate was 20.7% (11 patients), with only one patient requiring blood transfusion due to pseudoaneurysm.

CONCLUSIONS

The use of non-papillary access for PCNL in the treatment of staghorn stones resulted in promising results in terms of stone-free rate, operating time, complication rate, hemoglobin drop and reduced the number of percutaneous tracts. These parameters of the current investigation were directly comparable to current literature. The safety and efficacy of a non-papillary approach for the treatment of staghorn stones could be advocated.

Endoscopic combined intrarenal surgery (ECIRS) - Tips and tricks to improve outcomes: A systematic review

OBJECTIVE

This study aimed at assessing current efficacy and safety of endoscopic combined intrarenal surgery (ECIRS) for the treatment of large and/or complex urolithiasis and identifying relevant tips and tricks able to improve its outcomes, mainly deriving from the adjunct of retrograde flexible ureteroscopy to the traditional antegrade approach of percutaneous nephrolithotomy (PNL).

MATERIAL AND METHODS

A systematic review was conducted using relevant databases (Ovid Medline, PubMed, Scopus, and Web of Sciences), employing "ECIRS" as the search term in all cases, and then adding "endoscopic combined intrarenal surgery" and "flexible ureteroscopy AND percutaneous nephrolithotomy" as search terms for PubMed and Scopus. Original articles and systematic reviews were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Additionally, the reference lists of the selected publications were checked manually.

RESULTS

A total of 14 studies were selected for analysis: two systematic reviews, one randomized controlled trial, five nonrandomized comparative studies, three prospective case series, and three retrospective case series. ECIRS achieves high stone-free rates and rather low/low Clavien-Dindo grade complication rates, confirming the role of retrograde ureteroscopy in the maximization of its efficacy and safety. A narrative synthesis of the most recognized tips and tricks of ECIRS is provided.

CONCLUSION

The contribution of retrograde flexible ureteroscopy during PNL is essential. It plays a dual role, both diagnostic and active, allowing tailoring of the procedure to the patient, urolithiasis, and anatomy of the collecting system and optimization of the PNL efficacy and safety. This is ECIRS: an updated, complete, and versatile version of PNL.

[Navigation systems for the percutaneous access to the kidney]

BACKGROUND

Percutaneous access to the renal pelvis still remains the most difficult step before nephrolitholapaxy (PCNL). New imaging techniques, such as 3D imaging and various navigation instruments such as electromagnetic, sonographic, CT-controlled and marker-based/iPAD try to simplify this step and reduce complications.

OBJECTIVES

In this review, various new techniques for puncturing the renal collecting system are presented and their advantages and disadvantages are evaluated.

MATERIALS AND METHODS

A systematic literature search was carried out in MEDLINE, whereby only puncture techniques that have already been evaluated in clinical studies were included.

RESULTS

Five different navigation methods for puncturing the renal pelvis before PCNL were found.

CONCLUSION

Intraoperative navigation can be useful when puncturing the collecting system. The combination of ultrasound and fluoroscopy currently remains the gold standard. However, there is still a need for further, primarily clinical, prospective studies to determine which new imaging technology and navigation systems will prevail and thus facilitate the access route to the kidney, especially in the case of special anatomical conditions.

Minimally invasive percutaneous nephrolithotomy (PCNL): Techniques and outcomes

Minimally invasive percutaneous nephrolithotomy (PCNL) was introduced to decrease the morbidity of the standard PCNL (sPCNL). Thereafter, many modifications and techniques have been presented with the introduction of different miniaturized PCNL (mPCNL) techniques, such as micro-PCNL and ultra-mini-PCNL (UMP). As of present, none of the techniques has displaced the sPCNL. Nonetheless, mini-PCNL has continuously widening indications and has been proposed to have significant advantages over sPCNL. In the current review, each technique is presented while discussing the advantages and disadvantages of each approach. A comprehensive review of the current literature has been performed. Articles related to the topic were retrieved and critically analyzed. Less peri-operative bleeding and shorter hospital stay were the most important advantages advocated for mini-PCNL. Although the performance of mini-PCNL is safe, the utilization of micro-PCNL and UMP should be done with caution.

Critical causes in severe bleeding requiring angioembolization after percutaneous nephrolithotomy

Background

To identify the risk factors for severe bleeding requiring angioembolization among patients who received transfusions after PCNL, particularly those who underwent anatomically incorrect renal puncture.

Methods

A total of 53 patients, who received transfusions after PCNL and simultaneously had a postoperative CT scan performed between November 2009 and May 2019 at two teaching hospitals, were retrospectively reviewed. The patients were divided into two groups: those who underwent angioembolization and those who did not. Patient, stone and procedural factors were compared between the two groups. Puncture correctness was evaluated using postoperative CT scans. Puncture was defined as being a correct puncture if the fornix or papilla of the posterior calyx was punctured and the trajectory of the tract was within 20 degrees posterior to the frontal plane of the kidney (i.e., within Brödel’s line).

Results

21 patients underwent angioembolization after PCNL. Incorrect puncture was seen in 14/21 (66.7%) patients who underwent angioembolization after PCNL, whereas it was seen in 11/32 (34.4%) patients who did not undergo angioembolization (p = 0.021). On multivariable regression analysis, puncture correctness was found to be the only significant factor, with an OR of 3.818, 95% CI of 1.192–12.231 and p value of 0.024.

Conclusions

Incorrect renal puncture was related to severe bleeding requiring angioembolization after PCNL. Our results emphasize the importance of the basic principle of renal puncture for PCNL.

The Analysis of Risk Factors for Hemorrhage Associated with Minimally Invasive Percutaneous Nephrolithotomy

Objective

This study investigated the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy, so as to prevent the occurrence of bleeding and improve the surgical effect.

Patients and Methods

The data of 396 patients who underwent percutaneous nephrolithotomy by an experienced surgeon between May 2014 and December 2017 were retrospectively analyzed. To identify the risk factors for bleeding during percutaneous nephrolithotomy, each group was stratified according to the decrease in median hemoglobin. Age, gender, body mass index, stone size, operation time, stone type, degree of hydronephrosis, number of accesses, puncture guidance, underlying disease (diabetes; hypertension), and previous surgical history were evaluated. Univariate analysis was performed to calculate the potential factors. In order to determine the independence of each factor, we finally selected stone size, staghorn stone, degree of hydronephrosis, and operation time. Multivariate logistic regression analysis was used to identify the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy.

Results

A total of 396 patients were successfully treated with percutaneous nephrolithotomy. The univariate analysis demonstrated that the potential risk factors for bleeding during percutaneous nephrolithotomy included stone size, type of stone, operative time, and degree of hydronephrosis. According to the previous studies, stone size, staghorn stone, degree of hydronephrosis, and operation time were ultimately selected. Multivariate logistic regression analysis was used to identify the risk factors for bleeding during percutaneous nephrolithotomy. According to the outcome of logistic regression analysis, stone size, staghorn stone, operation time, and degree of hydronephrosis were the risk factors for bleeding during minimally invasive percutaneous nephrolithotomy.

Conclusions

Percutaneous nephrolithotomy is an effective method for the treatment of upper urinary calculi with few complications. According to the results achieved by an experienced surgeon, the size of stone, staghorn stone, operation time, and degree of hydronephrosis were associated with the bleeding during minimally invasive percutaneous nephrolithotomy.

Is emergency percutaneous antegrade drainage of the upper urinary tract useful for future percutaneous nephrolithotomy access?

Purpose

To compare percutaneous nephrolithotomy (PCNL) operations between patients with a preoperative nephrostomy tube and patients that the renal access was obtained at the time of the surgery.

Materials and Methods

We retrospectively evaluated PCNL cases. Patients were divided into two groups. Group 1 – a non-nephrostomy tube (percutaneous nephrostomy, PCN) group and Group 2 – patients with a PCN placed before the procedure. All preoperatively placed PCN's were performed in emergency situations by interventional radiologists (IR). Complications were classified according to the Clavien-Dindo classification. We compared stone characteristics, operation time, complications, efficacy and PCN usability at surgery.

Results

Five hundred twenty-seven patients who were submitted to PCNL for renal stones were included in the study. In 73 patients (13.9%) the PCNs were placed before the surgery. Patients and stone characteristics, mean operative time (p=0.830), complications (p=0.859) and stone-free rates (93.0%) were similar between the groups. There was a trend toward higher complication rates in Group 1, but the difference was not statistically significant. Only 21 (29.0%) of preoperatively placed PCNs were used during PCNL for establishing a tract. The reasons for not using PCN tract were: pelvic or infundibular insertion (30.0%) and suboptimal anatomic location (70.0%).

Conclusions

Preoperative emergency inserted PCNs by IR usage rates were low during PCNL. Its placement neither affects the incidence of complications nor affects the operation time and outcomes. As such, when emergency renal drainage is indicated, the need for a future definitive PCNL should not influence the decision about the modality of renal drainage.

Updates in endourological management of urolithiasis

Urinary stone disease, or urolithiasis, is a very common disease with increasing prevalence and incidence. With the advancement of endoscopic techniques, the treatment outcomes of ureteroscopy (or transureteral lithotripsy) and percutaneous nephrolithotomy are continuously improving. In recent years, there have been many new developments in the field, including new endoscopy design, more effective auxiliary tools, improvement in treatment protocols, introduction of robotic technology, combining both ureteroscopy and percutaneous nephrolithotomy (endoscopic combined intrarenal surgery or transureteral lithotripsy-assisted percutaneous nephrolithotomy), improvement in laser technology, and so on. All these new inputs will further improve the treatment efficacy and safety of the procedures, thus benefiting our patients. In the present review, we briefly go through the main steps of ureteroscopy and percutaneous nephrolithotomy, with a concise description and application of these new advances.

The Anatomic Structure of a Fused Renal Pyramid and Its Clinical Significance in the Establishment of Percutaneous Renal Access

OBJECTIVE

To explore the clinical significance of the fused renal pyramid (FRP) in establishing percutaneous renal access, and the anatomic basis for avoiding vascular injury caused by puncturing through this renal pyramid with the aim of achieving accurate puncture in percutaneous nephrolithotomy.

MATERIALS AND METHODS

Sixty-two cadaveric kidneys and 105 porcine kidneys were selected for the assessment of regional anatomy, to explore the anatomic structure of the FRP and determine its frequency. Then, we compared the effects of 4 different puncture paths on the occurrence of renal vascular injury when respectively punctured through the normal renal pyramid (group A), the centerline of one side pyramid of the FRP (group B), the center of the entire FRP (group C) and the renal column (group D).

RESULTS

The incidence of FRP in human kidneys is not low. The artery in the kidney can be divided into 6 grades. The grade IV branch-interlobar artery courses through the FRP. There was significant difference in the degree of arterial injury between the group A and C (P = .003), while no significant difference between the group A and B (P = .151). There was significant difference in the proportion of interlolar artery injury between group A and C (P <.001), while no significant difference between group A and B (P = .239).

CONCLUSION

It is necessary to carefully identify and bypass the FRP when establishing a percutaneous renal access. If unavoidable, the puncture path should be on the centerline of one side pyramid of the FRP.

Percutaneous Nephrolithotomy Puncture and Tract Dilation: Evidence on the Safety of Approaches to the Infundibulum of the Middle Renal Calyx

OBJECTIVE

To investigate the anatomical relations of the papillary, infundibular, and pelvic approach to percutaneous nephrolithotomy and evaluate the amount of vascularization at the respective sites.

MATERIALS AND METHODS

^99mTc-dimercaptosuccinic acid single-photon emission computed tomography/computed tomography (SPECT/CT) renal scintigraphies or computed tomography perfusion (CTP) was performed in 40 patients (prone n = 20 or supine position n = 20). The angle of approach (AoA) for access tracts and the respective regions of interest to the mid-calyceal papilla and infundibulum as well as renal pelvis were designed and compared.

RESULTS

The design of access tracts aiming to the renal pelvis, papilla, and infundibulum of the renal calyx was impossible for the nondilated collecting systems as all these tracts were in close vicinity. In both SPECT/CT and CTP, there was no statistical difference between the AoA for infundibular or pelvic access in comparison with the papillary puncture in either prone or supine position regardless of the degree of dilation of the system. The comparison of the measurements in the regions of interest showed that there was no difference in blood supply between the infundibular and pelvic access in comparison with the papillary approach in both positions regardless of the degree of collecting system dilation.

CONCLUSION

The use of SPECT/CT and CTP showed that the punctures to the mid-calyceal renal papilla-fornix and infundibulum as well as the renal pelvis at the same level have similar AoA. The sites of the parenchyma involved in the tract dilation of the respective approaches are not related to significant differences in terms of vascularization.