Renal Access In Percutaneous Nephrolithotomy Research Articles

Ultrasound-guided percutaneous nephrolithotomy versus conventional c-arm-guided percutaneous nephrolithotomy: a prospective randomized comparative study

BackgroundUltrasound guidance for renal access in percutaneous nephrolithotomy (PCNL) is a safe, effective, and low-cost procedure. The current study compared the safety and effectiveness of ultrasound-guided PCNL (US-PCNL) for renal stone therapy versus fluoroscopy-guided PCNL (FL-PCNL) in prone position.ResultsSuccessful puncture was attained in all cases in both groups. Unlike fluoroscopy, US guidance reduced the time needed for achieving renal puncture that was (22.45 ± 6.95 s) compared to fluoroscopy that was (68.28 ± 56.76 s) (P value < 0.001). The mean duration of access that was reported in our study was (3.92 ± 0.72 min) in the US-PCNL group and (4.03 ± 0.77 min) in the FL-PCNL group (P value 0.460). There was no significant difference in the total operative time between both groups in our study as the mean operative time in the US-PCNL group was (61.47 ± 6.07 min) and (65.86 ± 20.86 min) in the FL-PCNL group with a (P value of 0.349). Stone-free rate was nearly similar in both groups (P value 0.336). Three cases in our study in the FL-PCNL group had bleeding that required blood transfusion post-operative; mean Hb change was 0.23 g/dL and 0.55 g/dL in US-PCNL and FL-PCNL groups, respectively, which is clinically irrelevant despite statistical significance (P value 0.007). Mean fluoroscopy time was (6.38 ± 3.84) minutes in FL-PCNL group.ConclusionUltrasound guidance is a reliable tool in the hands of experienced urologists in performing PCNL with less or even zero radiation.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques

Percutaneous nephrolithotomy confers the highest radiation to the urologist’s hands compared to other urologic procedures. This study compares radiation exposure to the surgeon’s hand and patient’s body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon’s hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon’s hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey’s B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon’s hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

Effects of standardized language on remote ultrasound-guided percutaneous nephrolithotomy training: A mixed-methods explorative pilot study

BackgroundRemote teaching of procedural skills has demonstrated equivalence in knowledge acquisition compared to in-person teaching. Variations in terminology for probe and needle movements may serve as a barrier in remote training of ultrasound (US)-guided renal access for percutaneous nephrolithotomy (PCNL). This pilot study investigated the utility of standardized terminology in remote training of US-guided renal access for PCNL. HypothesisStandardization of verbal terminology to describe US probe and needle movement instruction improves remote teaching of US-guided renal access. MethodsFifteen urology residents (PGY1-6) were stratified by year and randomized into two groups. We provided participants with images illustrating US probe and needle movements labeled with predetermined standardized terminology for the intervention group and images without labels for the control group. Both groups were asked to perform US-guided renal access on a training mannequin with a remote faculty educator with (intervention) or without (control) use of standardized movement instructions. Quantitative outcomes included number of attempts and time to achieve access. All trainees completed pre- and post-session surveys and participated in focus groups; authors conducted thematic analysis of focus group transcripts. ResultsDifferences in primary outcomes between groups, including number of attempts and time to achieve access of the renal pole, were not statistically significant. Analysis of focus group interviews revealed that the use of standardized terminology in the setting of remote training can reduce trainee confusion by clarifying ambiguity in educator feedback. DiscussionUse of standardized terminology during remote surgical skills training allows for more effective feedback to trainees.

Re: A Randomized, Single-blind Clinical Trial Comparing Robotic-assisted Fluoroscopic-guided with Ultrasound-guided Renal Access for Percutaneous Nephrolithotomy

Re: A Randomized, Single-blind Clinical Trial Comparing Robotic-assisted Fluoroscopic-guided with Ultrasound-guided Renal Access for Percutaneous Nephrolithotomy

A Randomized, Single-Blind Clinical Trial Comparing Robotic-Assisted Fluoroscopic-Guided with Ultrasound-Guided Renal Access for Percutaneous Nephrolithotomy.

We conducted a randomized, single-blind clinical trial comparing the surgical outcomes of robotic-assisted fluoroscopic-guided (RAF group) and ultrasound-guided (US group) renal access in mini-percutaneous nephrolithotomy (PCNL). We recruited patients who underwent mini-PCNL with ureteroscopic assistance for large renal stones between January 2020 and May 2021. Block randomization was performed using online software. Automated needle target with x-ray was used for fluoroscopic-guided renal access in the RAF group. PCNL was performed by residents using a pneumatic lithotripsy system with 16.5Fr/17.5Fr tracts. The primary outcome was single puncture success, and the secondary outcomes were stone-free rate, complication rate, parameters measured during renal access and fluoroscopy time. In total, 71 patients (35 in US group, 36 in RAF group) were enrolled. No difference was seen in the single puncture success rate between the US and RAF groups (34.3% and 50.0%, p=0.2). In 14.3% cases in the US group vs no cases in the RAF group, the resident was unable to obtain access due to difficult targeting (p=0.025). The mean number of needle punctures was significantly fewer, and the median duration of needle puncture was shorter in the RAF group (1.83 vs 2.51 times, p=0.025; 5.5 vs 8.0 minutes, p=0.049, respectively). The stone-free rate at 3 months after surgery was 83.3% and 70.6% in the RAF and US groups, respectively (p=0.26). Multivariate analysis revealed that RAF guidance reduced the mean number of needle punctures by 0.73 times (p=0.021). RAF renal access in mini-PCNL may have further potential applications in this field.

Renal puncture access using a blunt needle: proposal of the blunt puncture concept

PurposeSevere haemorrhage in percutaneous nephrolithotomy (PCNL) is an alarming event, and preventing injury to renal major vessels is a challenge. We evaluated the efficiency of a blunt needle in renal puncture procedures.MethodsWe first retrospectively reviewed the embolization images of post-PCNL patients to analyse the types of arteries injured, which were considered target arteries. Then, either a blunt needle or a conventional needle was used to directly puncture target arteries in ex vivo porcine kidneys and to establish renal access ex vivo and in vivo. The primary outcome was the incidence of target artery injuries, which were observed by digital subtraction angiography, nephroscopy and 3-dimensional endocasts. The secondary outcome was the rate of excreted fluid per access.ResultsThe segmental and interlobar arteries were the most common types of injured arteries that needed to be embolized after PCNL. When these arteries were punctured directly, blunt needles reduced injury (1/20 vs. 16/20; OR 4.750; 95% CI 1.966–11.478; P < .001) by 76% compared to injuries induced by conventional needles. Moreover, the blunt needle group also had a significantly lower incidence of these arteries’ injuries ex vivo due to renal puncture and yielded a lower rate of excreted fluid in ex vivo and in vivo renal puncture procedures.ConclusionA blunt needle for renal puncture can be effective in reducing injury to renal major arteries and the accompanying haemorrhage. We propose the concept of blunt puncture, which may be a promising method for achieving safe renal access in PCNL.

A Different and Novel Alternative (ADANA) Renal Access Technique when CT or USG Guidance Is Inadequate in Case of Retro-Renal Colon

Introduction: Computed tomography (CT) or ultrasonography (USG)-guided renal access for percutaneous nephrolithotomy (PNL) is not suitable in all cases with retro-renal colon (RRC) due to anatomical and technical restrictions. We would like to describe our novel technique that permits standard subcostal renal access with a small incision for these patients. Methods: This method was performed on adult patients with severe RRC and complex renal stones who were not suitable for renal access with CT or USG guidance. Time from skin incision to puncture needle insertion, incision length, stone-free rate (SFR), and complications were evaluated. Surgical Technique: The appropriate renal calyx for renal access was identified with retrograde pyelography. The skin closest to the identified calyx was incised and retroperitoneum visualized. The RRC was swept laterally by blunt dissection to obtain a safe puncture line. The retractors were placed to keep the colon away from the incision. Then, the puncture needle was placed over Gerota’s fascia. After this, the puncture needle was inserted into the targeted calyx under fluoroscopic guidance. The insertion of guidewire and the rest of the procedure such as dilatation and insertion of Amplatz sheath were performed under same maneuver. Results: A total of 1,348 patients were treated with PNL between January 2016 and November 2019. Our group consisted of 16 adult patients with a median age of 44.8 years (7 females and 9 males) who underwent PNL with our new access technique. SFR and clinically insignificant residual fragment (CIRF) rate were 72.5 and 14.2%, respectively. The median access time was 22.2 min (range: 15–30 min). The median skin incision length was 3.7 (range: 3.0–4.5) cm. The average skin incision length was 3.7 cm. The SFR and CIRF rate were 72.5 and 14.2%, respectively. We did not observe any complication related to our access technique. Conclusion: Our novel access technique created a safe anatomical route for standard subcostal renal access with acceptable incision length and very low complication rate.

106 - Renal access in percutaneous nephrolithotomy (PCNL) under sonographic guidance: Do we really need to insert an open end ureteral catheter in dilated renal systems?

106 - Renal access in percutaneous nephrolithotomy (PCNL) under sonographic guidance: Do we really need to insert an open end ureteral catheter in dilated renal systems?

PD19-09 ULTRASOUND-GUIDED RENAL ACCESS REDUCES RADIATION EXPOSURE DURING PERCUTANEOUS NEPHROLITHOTOMY COMPARED TO FLUOROSCOPIC GUIDANCE

INTRODUCTION AND OBJECTIVES: In the United States, renal access for percutaneous nephrolithotomy (PCNL) is most commonly performed using fluoroscopic guidance. Fluoroscopy provides good structural visualization of the collecting system but requires the use of ionizing radiation. Ultrasonography (US) is an alternative imaging modality for achieving percutaneous renal access and provides both collecting system and visceral imaging compared to fluoroscopy. The purpose of this study is to compare radiation exposure and surgical outcomes for PCNL between cases performed with USversus fluoroscopy-guided renal access. METHODS: This prospective cohort study enrolled 118 PCNL cases from the UCSF hospital system between May 2014 and May 2015, of which 48 were performed with fluoroscopic guidance (group 1) and 70 with US guidance (group 2) for percutaneous renal access. USguided cases were those for which US was utilized for all or the majority of renal access, while fluoroscopy-guided cases were those done purely using fluoroscopy. The main variables measured included radiation dose, total operative time, residual stone status, serum creatinine change, hematocrit change, perioperative transfusion rate, surgical complication rate (Clavien class >2), and hospital length of stay. RESULTS: Groups 1 and 2 were comparable, having mean ages of 53.9 13.8 vs. 54.2 12.2, percent male patients of 43.8% vs. 41.4%, mean BMI of 30.9 8.1 vs. 29.3 9.8, and mean ASA physical status classification of 2.1 0.6 vs. 2.3 0.7, respectively. Patients in group 2 received less total mean radiation dose (18.5 mGy vs. 46.0 mGy, P<.01) and fluoroscopic screening time (68.9 sec vs. 169.5 sec, P<.01) compared to group 1. An average radiation dose reduction of 27.5 mGy (95% CI 7.8 to 47.3) was observed. There were no statistically significant differences in mean values for total operative time (156 vs. 159 min P1⁄4.77), change in serum creatinine (.03 vs .03, P1⁄4.95), change in hematocrit (-2.8 vs. -4.1, P1⁄4.16), transfusion rate (2.1% vs. 1.4%, P1⁄41.0), complication rate (4.2% vs. 4.3%, P1⁄41.0), residual stone status (16.7% vs. 21.4%, P1⁄4.23), and hospital length of stay (2.9 days vs. 3.1 days, P1⁄4.62). CONCLUSIONS: Ultrasound guidance for percutaneous renal access results in reduced radiation exposure for patients during PCNL and has no negative effects on surgical outcomes or efficacy of the procedure when compared to fluoroscopic guidance.

The Outcome of Percutaneous Nephrolithotomy Using Intravenous Catheter for Obtaining Percutaneous Access as a Treatment for Renal Stone Disease in Children: A Pilot Study.

Using percutaneous nephrolithotomy (PNL), it is easy to reach stones in various parts of the kidney via a single access tract. In the current study, we set out to demonstrate that the intravenous catheter is a safe way to gain renal access, and that PNL is safe in children. We retrospectively reviewed the medical records of patients who underwent PNL as a treatment for renal stone disease at our center between September 2013 and December 2014. There were no specific exclusion criteria. We used 14 gauge intravenous catheter for renal access in all cases. Eleven of the 32 patients (34.4%) were female and 21 (65.6%) were male. The mean ± SD patient age was 4.7 ± 3.71 years (9 months-16 years). Six patients (18.7%) were infants less than 1 year of age. Fifteen of the stones (46.8%) were located in the right kidney, and 17 of the stones (53.1%) were located in the left kidney. The average stone size was 13.9 ± 4.8 mm (range, 12-28). The average duration of operation was 69.7 ± 10.4 minutes (range, 50-110), and the average duration of fluoroscopy was 2.21 ± 1.06 minutes (range, 1-6). There were complications in 5 of the cases (15.6%). The access and dilatation stages are quite important. We propose that the intravenous catheter is a safe and inexpensive tool for renal access in PNL in pediatric age group patients.

Ultrasound-Guided Renal Access for Percutaneous Nephrolithotomy: A Description of Three Novel Ultrasound-Guided Needle Techniques.

Ultrasound-guided renal access for percutaneous nephrolithotomy (PCNL) is a safe, effective, and low-cost procedure commonly performed worldwide, but a technique underutilized by urologists in the United States. The purpose of this article is to familiarize the practicing urologist with methods for ultrasound guidance for percutaneous renal access. We discuss two alternative techniques for gaining renal access for PCNL under ultrasound guidance. We also describe a novel technique of using the puncture needle to reposition residual stone fragments to avoid additional tract dilation. With appropriate training, ultrasound-guided renal access for PCNL can lead to reduced radiation exposure, accurate renal access, and excellent stone-free success rates and clinical outcomes.

PD37-09 THE LASER-DARRT: A NOVEL DIRECT ALIGNMENT REDUCED RADIATION TECHNIQUE FOR PERCUTANEOUS RENAL ACCESS

INTRODUCTION AND OBJECTIVES: The traditional bullseye technique for obtaining renal access in percutaneous nephrolithotomy (PCNL) utilizes continuous fluoroscopy and accounts for substantial radiation exposure. In an attempt to minimize the radiation dose, we describe a novel laser-DARRT (Direct Alignment Reduced Radiation Technique) using direct alignment of the percutaneous access needle with the laser beam from the fluoroscopic C-arm system. METHODS: In the laser-DARRT technique, fluoroscopy was used to select the needle entry site above the calyx of interest. The Carm was positioned with the laser beam on the skin over the desired access site at a 30 degree angle. The access needle was placed such that the needle tip and hub were both aligned with the laser beam. The needle was inserted into the renal calyx using tactile feedback while maintaining alignment with the laser. Needle depth and successful calyceal puncture were confirmed both fluoroscopically and under direct vision. A randomized-controlled study was performed using a benchtop kidney model. Twenty medical personnel were tested using both the bullseye and laser-DARRT techniques and the results were stratified by subject experience level. Each subject obtained needle access to the upper, middle, and lower pole of the kidney model using both techniques. The primary endpoint was total fluoroscopy time. Secondary endpoints included insertion time, number of puncture attempts, number of course corrections, and subjective procedural difficulty. Paired samples Wilcoxon signed rank tests were used for statistical analysis with significance at p<0.05. RESULTS: A total of 120 needle placements were recorded by the 20 study subjects (60 conventional and 60 Laser DARRT). The fluoroscopy time required to obtain needle access using the LaserDARRT technique was significantly reduced compared to the conventional technique in all groups, including the attendings/fellows (7.09 vs. 18.51 sec; p<0.001), residents (6.55 vs. 13.93 sec; p1⁄40.001), and medical students (6.69 vs. 20.22 sec; p<0.001). The medical students also rated the Laser DARRT technique easier to use (2.56 vs. 4.89; p<0.001). No difference was seen in total access time, puncture attempts, or course corrections between techniques. CONCLUSIONS: The laser-DARRT for percutaneous renal access reduced fluoroscopy time by 63% compared with a conventional bullseye technique. The least experienced users found the laserDARRT significantly easier to learn. This is a promising new technique that merits additional testing in animal and human models.

Comparison of urologist- and radiologist-gained percutaneous renal access during PCNL: a review

Percutaneous renal access for percutaneous nephrolithotomy (PCNL) can be performed by either an interventional radiologist or urologist, depending on local expertise. We reviewed the current literature comparing the success and complications in gaining percutaneous access for both groups. An extensive literature search was carried out using Medline which included keywords “PCNL”, “PCNL access”, “percutaneous nephrolithotomy” and “percutaneous nephrostomy”. The search yielded six published articles that compared the success and complication rates between urologist- and radiologist-performed percutaneous access for PCNL. A systematic literature review was performed. Because of the considerable heterogeneity between studies, no pooling of data or statistical analysis was undertaken. In terms of success or complication rates, there was no significant difference between urologist- and radiologist-made percutaneous tracts. We observed, however, that there appears to be an argument that urologists are in a better position to make their own tracts, which requires only a single-stage procedure in theatre. There appears to be low uptake amongst urologists with the common beliefs that it is a radiological procedure, that radiologists have superior equipment, that it increases intraoperative time and that a steep learning curve is required for proficiency, suggesting that competence in percutaneous access would require at least 60 PCNL procedures. It is therefore unsurprising that many trainees may struggle to gain sufficient exposure to this technique, unless they are training in a centre with adequate patient numbers. Nonetheless, the papers reviewed illustrate that the urologists who are practicing this procedure are performing to an acceptably high standard. In conclusion there appears to be no difference in complication rates between the urologist- and the radiologist-made percutaneous tract. The steep learning curve required can be addressed by new teaching methods such as inanimate simulators, virtual-reality (VR) simulators, PCNL workshops and old-fashioned apprenticeships. A prospective study comparing urologist- and radiologist-placed nephrostomies would be beneficial.

Safety and efficacy of ultrasonography as an adjunct to fluoroscopy for renal access in percutaneous nephrolithotomy (PCNL)

• To evaluate the safety and efficacy of ultrasonography (US)-guided renal access in percutaneous nephrolithotomy (PCNL), as compared with conventional fluoroscopy-guided renal access in a prospective randomized trial. • From January 2008 to October 2009, 224 patients with renal calculi undergoing PCNL were randomized into two groups. • Group 1 (112 patients) underwent PCNL using only fluoroscopy-guided renal access; while in group 2 (112 patients), US guidance for puncture was used in addition to fluoroscopy. • The inclusion criteria were: normal renal functions, American Society of Anesthesiology scores 1 or 2, absence of congenital abnormalities, aged 15-70 years, and anticipated single-tract procedure. The patients in both groups were matched for age, sex, and stone characteristics. • The Student t-test was used for statistical analysis with an allowable error of 5%. • The mean time to successful puncture was 3.2 min and 1.8 min in group 1 and group 2, respectively (P < 0.01). • The mean duration of radiation exposure to successful puncture was 28.6 s in group 1 and 14.4 s in group 2 (P < 0.01). • The mean numbers of attempts for successful puncture in the desired calyx was 3.3 in group 1 as compared with 1.5 in group 2 (P < 0.01). • The meantime taken for tract formation in group 1 was 7.4 min with radiation exposure of 82 s, while in group 2 it took 4.8 min with radiation exposure of 58 s (P < 0.01). • Successful access was achieved in all patients. All patients were stone-free at the end of the operation. The hospital stay (2-3 days) was same in both groups. There was no incidence of significant bleeding requiring transfusion during or after surgery. All the patients were followed-up for a ≥ 6 months. • US-guided puncture in PCNL helps in increasing accuracy of puncture and decreasing radiation exposure for the surgical team and the patients.

UP-1.056: Comparative Study of Standard and Mini-Perc Renal Access in Percutaneous Nephrolithotomy

UP-1.056: Comparative Study of Standard and Mini-Perc Renal Access in Percutaneous Nephrolithotomy

UP-3.177: Comparative Study of Ultrasonographic with Fluoroscopic Guided Renal Access in Percutaneous Nephrolithotomy

UP-3.177: Comparative Study of Ultrasonographic with Fluoroscopic Guided Renal Access in Percutaneous Nephrolithotomy

Renal Access by Urologist or Radiologist for Percutaneous Nephrolithotomy—Is it Still an Issue?

Despite evidence that urologists can safely acquire percutaneous renal access for percutaneous nephrolithotomy, many centers still rely on interventional radiologists to obtain renal access. In this study we evaluated percutaneous access for percutaneous nephrolithotomy obtained by interventional radiologists or urologists, and compared access outcomes and complications. The surgical records of 1,121 patients with 1,155 stone bearing kidneys treated with percutaneous nephrolithotomy between 1999 and 2003 were reviewed. Patients were stratified according to percutaneous renal access into 509 patients with 661 access procedures performed by urologists and 612 patients with 612 access procedures performed by interventional radiologists. Both groups were comparable except there was a higher incidence of multiple stones in the urologist access group. Urologists had a significantly greater rate of using multiple and supracostal tracts compared to radiologists. The stone-free rates were 83.4% and 86.1% for urologist and radiologist access groups, respectively (p = 0.1). Major complications were seen in 74 patients (6.6%). Both groups had similar complication rates except for significant bleeding in the urology group (4.3%) compared with 2.1% in the radiology cohort (p = 0.02). Further multivariate analysis showed that bleeding was not related to the type of access whether performed by urologist or radiologist. The urologist is able to safely and effectively obtain percutaneous renal access for percutaneous nephrolithotomy as a single stage procedure. Despite more complex stones and higher access difficulty in the urology access group, access related complications and stone-free rates were comparable. We recommend percutaneous access training in urology training programs.