New Technologies to Aid in Percutaneous Access

Renal Access in Pediatric Supine Miniaturized Percutaneous Nephrolithotomy: Comparative Evaluation of Ultrasound-Fluoroscopy Combined and Biplanar (0°-90°) Fluoroscopic Techniques

Introduction: Ultrasound (US)-guided puncture has the benefits of avoiding radiation and limiting the risk of visceral injury. We aimed to evaluate the results of two different renal access techniques during pediatric supine mini percutaneous nephrolithotomy (smPCNL) in a comparative manner. Patients and Methods: Data obtained from pediatric patients undergoing smPCNL by single surgeon between September 2021 and 2023 were reviewed retrospectively. Children were divided into two groups namely; biplanar 0°-90° fluoroscopy (Group-F) and US-fluoroscopy combined (Group-C). In all cases, preoperative, operative, and postoperative findings were recorded. Success was defined as the determination of either no (complete stone-free status) or < 4 mm residual fragments (CIRF) on US and X-ray (postoperative 3rd month) images. Complications were evaluated according to modified Clavien-Dindo classification. Results: Data of 54 patients with a mean age of 8.6 years (Group-F = 30, Group-C = 24) are reviewed. In addition to the similar success rates in both groups (Group-F = 86.7% Group-C = 87.5% p = 0.928), similar minor complications were noted in the majority of the cases. No child required transfusion and/or angioembolization. Although the fluoroscopy and operation time were lower in Group-C, the difference was not statistically significant. Conclusion: US-fluoroscopy combined access technique can be applied with similar success and complication rates in pediatric smPCNL. Ultimately, as experience is gained, this technique may lower radiation exposure, although this was not observed in the current study.

Robotic-assisted versus manual Uro Dyna-CT-guided puncture in an ex-vivo kidney phantom

INTRODUCTION AND OBJECTIVES

Challenging percutaneous renal punctures to gain access to the kidney requiring guidance by cross-sectional imaging. To test the feasibility of robotic-assisted CT-guided punctures (RP) and compare them with manual laser-guided punctures (MP) with Uro Dyna-CT (Siemens Healthcare Solutions, Erlangen, Germany).

MATERIAL AND METHODS

The silicon kidney phantom contained target lesions of three sizes. RP were performed using a robotic assistance system (guidoo, BEC GmbH, Pfullingen, Germany) with a robotic arm (LBR med R800, KUKA AG, Augsburg, Germany) and a navigation software with a cone-beam-CT Artis zeego (Siemens Healthcare GmbH, Erlangen, Germany). MP were performed using the syngo iGuide Uro-Dyna Artis Zee Ceiling CT (Siemens Healthcare Solutions). Three urologists with varying experience performed 20 punctures each. Success rate, puncture accuracy, puncture planning time (PPT), and needle placement time (NPT) were measured and compared with ANOVA and Chi-Square Test.

RESULTS

One hundred eighteen punctures with a success rate of 100% for RP and 78% for MP were included. Puncture accuracy was significantly higher for RP. PPT (RP: 238 ± 90s, MP: 104 ± 21s) and NPT (RP: 128 ± 40s, MP: 81 ± 18s) were significantly longer for RP. The outcome variables did not differ significantly with regard to levels of investigators' experience.

CONCLUSION

The accuracy of RP was superior to that of MP. This study paves the way for first in-human application of this robotic puncture system.

Comparison of safety and efficacy of one shot dilation vs. gradual dilation technique in supine percutaneous nephrolithotomy

PURPOSE

To compare the efficacy and safety of gradual dilation (GD) and one-shot dilation (OSD) techniques in patients who underwent supine percutaneous nephrolithotomy (PCNL).

METHODS

The data of 176 patients who underwent supine PCNL were reviewed. Eighty-seven patients who underwent OSD were defined as group 1, and 89 patients who underwent GD were defined as group 2. Both surgical techniques were compared with each other in terms of various parameters. Then, regression analysis of factors predicting stone-free status and complications in patients who underwent supine PNL were performed. Then, regression analysis of factors predicting success rate and complications in patients who underwent supine PNL were performed.

RESULTS

No statistical difference was found in terms of stone-free rate, Clavien-Dindo complication grade and operation time. No statistical difference was found in terms of success rate, Clavien-Dindo complication grade and operation time. However, the fluoroscopy time was found to be significantly shorter in group 1 (p < 0.001). In the analysis of factors predicting stone-free status, the presence of calyceal stones, increased stone size and number were associated with a decrease in stone-free rate. In the analysis of factors predicting success, the presence of calyceal stones, increased stone size and number were associated with a decrease in success rate. Increased fluoroscopy and operation time, increased complication rates were found to be significantly associated with residual stone. Analysis of factors predicting complications found a higher complication rate in patients with low BMI and severe hydronephrosis. Increased complication was associated with increased time to nephrostomy removal and hospital stay, decrease in stone-free rate, decrease in Hb and increase in Cre value at the postoperative 24th hour.

CONCLUSION

When comparing OSD and GD in patients undergoing supine PCNL, both techniques have similar stone-free and complication rates. When comparing OSD and GD in patients undergoing supine PCNL, both techniques have similar success and complication rates. Compared to GD, the OSD technique can be preferred primarily due to its shorter fluoroscopy time.

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.

Percutaneous Nephrolithotomy Access: A Meta-Analysis Comparing Access by Urologist vs Radiologist

Introduction: Percutaneous nephrolithotomy is a minimally invasive procedure indicated for the management of staghorn calculi or renal calculi >2.0 cm. Percutaneous renal access is a critical step in this procedure and can be performed by either urologists or interventional radiologists. The purpose of this study is to perform a meta-analysis to compare outcomes between urologist and interventional radiologist-mediated access. Methods: An electronic literature search was conducted to identify studies comparing urologist- and interventional radiologist-acquired access. Studies must have included both urologist- and intervention radiologist-acquired access data but were excluded if (1) not in English; (2) abstract without full text; (3) unable to determine who acquired access; and (4) only included either urologist or interventional radiologist data. Meta-analysis comparison was generated with the Review Manager 5.4 software. Results: After screening the abstracts and title, 55 relevant studies were identified. Nine articles were utilized in the meta-analysis. Urologist-acquired access was associated with a greater stone-free rate (risk ratio [RR] = 1.10; 95% confidence interval [CI], 1.01-1.20), a reduction in major complications (RR = 0.69; 95% CI, 0.53-0.92), and a shorter hospital stay (mean difference -0.40; 95% CI, -0.64 to -0.16) in comparison with radiologist-acquired access. Urologist-acquired access was associated with greater blood loss (mean difference 0.46; 95% CI, 0.32-0.60) when compared with interventional radiology-acquired access. No significant differences were found with regard to unusable access, multiple tracts, supracostal access, ancillary procedure requirement, operative time, minor complications, and transfusions. Conclusions: Urologist-acquired access may be associated with a higher stone-free rate and a reduction in major complications, whereas interventional radiologist-mediated access may be associated with a reduction in blood loss, despite similar transfusion rates.

Percutaneous nephrolithotomy - the puncture

OBJECTIVE

To determine what importance is given to the puncture and assistive technologies in percutaneous nephrolithotomy (PNL) in the current urological literature.

METHODS

PubMed was searched for English publications and reviews for the keywords: 'percutaneous nephrolithotomy', 'percutaneous nephrostomy', 'puncture'. The search was limited to the last 5 years, January 2016 until February 2021. Based on 183 abstracts, 121 publications were selected, read, and reviewed. References, older or seminal papers were read and cited if they contributed to a better understanding. A total of 198 references form the basis of this narrative review.

RESULTS

The puncture is frequently referred to as the most crucial part of PNL. In contrast, the influence of the puncture on the failure rate of PNL and the specific puncture-related complications seems to be low in the single-digit percentage range. However, there are no universally accepted definitions and standards measuring the quality of puncture. Consequently, the impact of the puncture on general PNL complications, on stone scores predicting success rates and on learning curves evaluating surgeons' performance have not been systematically studied. Assistive technologies rely on fluoroscopy and ultrasonography, the latter of which is becoming the preferred imaging modality for monitoring the entire procedure. Needle bending, a problem relevant to all puncture techniques, is not addressed in the urological literature.

CONCLUSIONS

The importance attached to puncture in PNL in the current urological literature is subjectively high but objectively low. Some basics of puncture are not well understood in urology. Disciplines other than urology are more actively involved in the development of puncture techniques.

Surgical Trends in Nephrolithiasis: Increasing De Novo Renal Access by Urologists for Percutaneous Nephrolithotomy

Purpose: Percutaneous nephrolithotomy (PCNL) has wide variability in the methods of renal access. In many centers, this is done as a separate nephrostomy procedure by interventional radiology, while other urologists gain initial access themselves during the PCNL. We aimed to characterize these trends to confirm the need for continued training in this aspect of PCNL. Methods: Using MarketScan insurance claims, we examined surgical volume for ureteroscopy (URS), extracorporeal shockwave lithotripsy (SWL), and PCNL during 2007-2017. For PCNL, current procedural terminology (CPT) codes were used to identify the provider performing the de novo renal access over time. We stratified postoperative outcomes for PCNL by provider type. Results: From 2007 to 2017, the annual proportion of PCNL procedures peaked at 4.5%, with a recent decline in 2016 and 2017 to 3.2%. URS steadily increased from 46.3% to 60.0% of procedures, and SWL mirrored that change with a decrease from 50.0% to 36.7%. Within 19,743 PCNLs, there was a notable increase from 12.8% to 32.3% in the number of procedures with urologists performing de novo renal access. Most cases (40.0%) still had a de novo access code assigned to a radiologist. Length-of-stay, readmission, transfusion, and secondary stone procedure rates were higher in the radiologist-gained access PCNLs. Conclusions: URS has surpassed SWL as the most common stone procedure. While the proportion of PCNLs has remained fairly stable over the last decade, urologists obtaining their own de novo access have increased substantially. Continued outreach efforts focused on urologist-obtained access may further increase this proportion and improve outcomes for PCNL.

Ultrasound or Fluoroscopy for Percutaneous Nephrolithotomy Access, Is There Really a Difference? A Review of Literature

Objective: To compare whether the outcomes of ultrasound-guided access percutaneous nephrolithotomy (USGA-PCNL) are similar to standard fluoroscopy-guided access percutaneous nephrolithotomy (FGA-PCNL). Methods: A review was developed by using the MEDLINE and Scopus databases and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Studies comparing the USGA-PCNL and the FGA-PCNL were included. Case reports, editorials and letters, unpublished studies, posters, and comments abstracts were excluded. Results: We found 12 published articles that compared USGA-PCNL and FGA-PCNL. These included six randomized controlled trials, three case-control trials, and three meta-analyses. The overall results showed no difference in the success of percutaneous access, bleeding, blood transfusion, operative time, postoperative complications, or hospital stay. Conclusion: The reported data demonstrate that there are no significant differences between the fluoroscopic-guided access PCNL and the ultrasonographic access PCNL. The choice of puncture depends on the surgeon's expertise in a particular technique and the patient and stone characteristics. Both approaches are equally safe and effective in experienced hands. It is important to recall that the use of one technique does not exclude the use of the other, and they can sometimes be complementary to each other.