Ultrasound-guided renal puncture followed by endoscopically guided tract dilatation vs standard fluoroscopy-guided percutaneous nephrolithotomy for non-opaque renal stones; a randomized clinical trial.

This study was designed to evaluate the non-inferiority of ultrasound puncture followed by endoscopically guided tract dilatation compared to the standard fluoroscopy-guided PCNL. Forty patients with non-opaque kidney stones eligible for PCNL were randomly divided into two groups. The standard fluoroscopy-guided PCNL using the Amplatz dilator was performed in the XRAY group. In the SONO group, the Kidney was punctured under an ultrasound guide followed by tract dilatation using a combination of the Amplatz dilator based on the tract length and an endoscopically guided tract dilatation using a bi-prong forceps in cases of short-advancement. The primary outcome was successful access. In 90% of cases in the XRAY and 95% in the SONO group access dilatation process was performed uneventfully at the first attempt (p = 0.5). In 45% of cases in the SONO group, bi-prong forceps were used as salvage for short-advancement. In one case in the X-ray group over-advancement occurred. One month after surgery, the stone-free rate on the CT-scan was 75% for the X-ray group and 85% for the SONO group (p = 0.4). There were no significant differences in operation time, hospitalization duration, transfusion, or complication rates between the two groups. We conclude that ultrasound-guided renal puncture, followed by endoscopically guided tract dilatation can achieve a high success rate similar to X-ray-guided PCNL while avoiding the harmful effects of radiation exposure and the risk of over-advancement.

One-Shot Dilatation vs Metal Dilator During Percutaneous Nephrolithotomy in Flank-Free Supine Position: A Randomized Controlled Study.

Background: The creation and dilatation of the nephrostomy tract is a fundamental step in percutaneous nephrolithotomy (PCNL). In one-shot dilatation (OSD), we used a single Amplatz dilator over a central Alken rod. PCNL in the supine position is as effective and safe as in the prone position. The Barts flank-free modified supine position sums several advantages of the different supine positions. We evaluated the efficacy and safety of OSD compared with metal telescopic dilator (MTD) during PCNL while the patient was in Barts flank-free modified supine position. Materials and Methods: Within 2.5 years, 150 patients with kidney stone candidates for PCNL were randomized into two equal groups according to the dilatation technique. In the OSD group, dilatation was performed using a single Amplatz dilator (30F) and in the MTD group dilatation was performed by sequential MTD (9-30F). All PCNL procedures were done with patients in Barts flank-free modified supine position. Patient characteristics, operative data, and results were collected for statistical analysis. Results: There are no statistically significant differences between both groups regarding patients' characters. The tracts were effectively dilated in all patients. Statistical analyses show a significant difference (p ˂ 0.05) between both groups regarding the time of dilatation (seconds; 68 ± 15 vs 147 ± 18), time of X-ray exposure (seconds; during dilatation; 36 ± 10 vs 61 ± 15 and the total; 157 ± 16 vs 181 ± 20), hemoglobin loss (mg/dL; 0.7 ± 0.2 vs 1.2 ± 0.3), and hospital stay (days; 3 ± 0.6 vs 3.7 ± 0.7) with favorable results to OSD. Complication rates were comparable between the two groups. Conclusions: OSD is efficient as MTD during PCNL while patients are in Barts flank-free modified supine position, with less dilatation time, X-ray exposure, blood loss, and hospital stay than MTD.

Comparative study between a new screwed Amplatz sheath and the ordinary one in percutaneous nephrolithotomy.

OBJECTIVE: The objective of the article is to compare the results of using new screwed Amplatz sheath with results of the conventional Amplatz sheath regarding success and complications during percutaneous nephrolithotomy. METHODS: 100 patients aged more than 18 years with renal calculi more than 2 cm with guy's score 1 from December 2018 till July 2020 were randomly stratified by closed envelope in group A (50 patients) with using conventional sheath and group B (50 patients) with new screwed sheath. We exclude morbid obese patients and patients with contraindication for PNL. RESULTS: There were no significant differences between both groups regarding patients demographic and stone demographic. Operative time and fluoroscopy time were significantly lower in group B rather than group A. Tract stability was in favor of group B as no tract loss recorded while in group A, 5 cases were recorded. In overall complications there were no significant differences between both groups. Bleeding was higher in group A (14%) than in group B (4%), but it was not statistically significant. Success rates were 78% for group A and 88% for group B but it was not statistically significant. CONCLUSION: The screwed Amplatz sheath had showed less operative and fluoroscopy time. Also it enables urologists to have stable PNL tract. So it may be a promising tool to make PNL easier with higher success rate and lower complications.

Cost analysis between mini-percutaneous nephrolithotomy with and without vacuum-assisted access sheath.

PURPOSE: To perform a cost analysis between vacuum-assisted percutaneous nephrolithotomy (vmPCNL) and minimally invasive PCNL (MIP) and explore potential predictors of costs associated with the procedures. METHODS: We analyzed data from 225 patients who underwent vmPCNL or MIP at a single tertiary referral academic center between January 2016 and December 2020. We collected patients' demographics, peri-and postoperative data and detailed expense records. After propensity score matching, 108 (66.7%) vmPCNL and 54 (33.3%) MIP procedures were analyzed. Descriptive statistics assessed differences in clinical and operative parameters. Univariable and multivariable linear regression models tested the association between clinical variables and costs. RESULTS: Operative time (OT) was shorter for vmPCNL, and the use of additional instruments to complete litholapaxy was more frequent in MIP (all p ≤ 0.01). Length of stay (LOS) was longer for MIP patients (p = 0.03) and the stone-free (SF) rate was higher after vmPCNL (p = 0.04). The overall instrumentation cost was higher for vmPCNL (p < 0.001), but total procedural costs were equivalent (p = 0.9). However, the overall cost for the hospitalization was higher for MIP than vmPCNL (p = 0.01). Univariable linear regression revealed that patient's comorbidities, OT, any postoperative complication and LOS were associated with hospitalization costs (all p < 0.001). Multivariable linear regression analysis revealed that LOS and OT were associated with hospitalization costs (all p < 0.001), after accounting for vmPCNL procedure, patients' comorbidities, and complications. CONCLUSION: vmPCNL may represent a valid option due to clinical and economic benefits. Shorter OT, the lower need for disposable equipment and the lower complication rate reduced procedural and hospitalization costs.

Mini Percutaneous Kidney Stone Removal: Applicable Technologies.

Percutaneous nephrolithotomy (PCNL) remains the treatment of choice for large and complex renal stones. The technological advances over the past several decades gave birth to different varieties of minimally invasive PCNLs, including the mini-PCNL, ultra-mini PCNL, super mini-PCNL, and micro-PCNL, with indications being extended to stones even larger than 20 mm. This article provides an update of all these available techniques of miniaturized PCNL along with its anatomic and physiologic impact. This should assist urologists in providing a personalized approach to the patient based on various patient- and stone-related factors to provide the best of all available technology for treatment.

Comparison of vacuum-assisted sheaths and normal sheaths in minimally invasive percutaneous nephrolithotomy: a systematic review and meta-analysis.

BACKGROUND: A systematic review and meta-analysis was conducted to compare the safety and efficacy of vacuum-assisted sheaths and conventional sheaths in minimally invasive percutaneous nephrolithotomy (MPCNL) in the treatment of nephrolithiasis. METHODS: PubMed, Web of Science, Embase, EBSCO, and Cochrane Library databases (updated March 2021) were used to search for studies assessing the effect of vacuum-assisted sheaths in patients who underwent MPCNL. The search strategy and study selection processes were implemented in accordance with the PRISMA statement. RESULT: Three randomized controlled trials and two case-controlled trials that satisfied the inclusion criteria were enrolled in this meta-analysis. Overall, the stone-free rate (SFR) in patients who underwent vacuum-assisted sheaths was significantly higher than that in patients who underwent conventional sheaths (RR 1.23, 95% CI 1.04, 1.46, P = 0.02), with significant heterogeneity among the studies (I2 = 72%, P = 0.03). In terms of the outcome of complications, vacuum-assisted sheath could bring a benefit to the postoperative infection rate (RR 0.48, 95% CI 0.33, 0.70, P < 0.00001) with insignificant heterogeneity among the studies (I2 = 0%, P = 0.68). There was no significant difference in the blood transfusion rate (RR 0.35, 95% CI 0.07, 1.73, P = 0.17), with significant heterogeneity (I2 = 66%, P = 0.35). Three studies contained operative time data, and the results indicated that the vacuum-assisted sheath led to a shorter operative time (MD = - 15.74; 95% CI - 1944, - 12.04, P < 0.00001) with insignificant heterogeneity (I2 = 0%, P = 0.91). CONCLUSION: The application of a vacuum-assisted sheath in MPCNL improves the safety and efficiency compared to the conventional sheath. A vacuum-assisted sheath significantly increases the SFR while reducing operative time and postoperative infection.

Efficacy and safety of the EMS Swiss LithoClast® Trilogy for PCNL: results of the European multicentre prospective study on behalf of European Section of UroTechnology.

PURPOSE: PCNL requires a lithotrite to efficiently break stones, and some devices include active suction to remove the fragments. We set out to determine the efficacy and safety of the Swiss LithoClast® Trilogy, in a prospective European multicentre evaluation and compared it to published stone clearance rates for Trilogy based on surface area (68.9 mm2/min) and using the 3D calculated stone volume (526.7 mm3/min). METHODS: Ten European centres participated in this prospective non-randomized study of Trilogy for PCNL. Objective measures of stone clearance rate, device malfunction, complications and stone-free rates were assessed. Each surgeon subjectively evaluated ergonomic and device effectiveness, on a 1-10 scale (10 = extremely ergonomic/effective) and compared to their usual lithotrite on a 1-10 scale (10 = extremely effective). RESULTS: One hundred and fifty seven PCNLs using Trilogy were included (53% male, 47% female; mean age 55 years, range 13-84 years). Mean stone clearance rate was 65.55 mm2/min or 945 mm3/min based on calculated 3D volume. Stone-free rate on fluoroscopy screening at the end of the procedure was 83%. Feedback for suction effectiveness was 9.0 with 9.1 for combination and 9.0 for overall effectiveness compared to lithotrite used previously. Ergonomic score was 8.1, the least satisfactory element. Complications included 13 (8.2%) Clavien-Dindo Grade II and 2 (1.3%) Grade III. Probe breakage was seen in 9 (5.7%), none required using a different lithotrite. CONCLUSIONS: We have demonstrated that Trilogy is highly effective at stone removal. From a user perspective, the device was perceived by surgeons to be highly effective overall and compared to the most commonly used previous lithotrite, with an excellent safety profile.

Double-sheath vacuum suction versus vacuum-assisted sheath minimally invasive percutaneous nephrolithotomy for management of large renal stones: single-center experience.

PURPOSE: To compare double-sheath vacuum suction minimally invasive percutaneous nephrolithotomy (DS-mini-PCNL) with vacuum-assisted mini-PCNL (VS-mini-PCNL) and to better define the potential benefits of DS-mini-PCNL. METHODS: Between July 2019 and May 2020, 117 patients with large radiopaque renal stones underwent mini-PCNL. Of these, 63 underwent DS-mini-PCNL and 54 underwent VS-mini-PCNL. For VS-mini-PCNL, a F20 Y-shaped sheath was used and the oblique arm of the sheath was connected to the vacuum suction. For DS-mini-PCNL, the oblique arm of a F20 Y-shaped sheath (the outer sheath) and a F16 Y-shaped sheath (the inner sheath) was connected to the perfusion inflow and the vacuum suction, respectively. A 550-µm holmium-YAG laser was used for stone fragmentation. RESULTS: Compared with VS-mini-PCNL group, DS-mini-PCNL group had significantly shorter operative time (35.78 ± 7.77 min vs. 44.56 ± 13.19 min; P = 0.000) and significantly lower fever rate (1.6% vs. 11.1%; P = 0.048). It was not significantly different between the two groups despite the higher initial stone-free rate seen for DS-mini-PCNL group relative to VS-mini-PCNL group (87.7% vs. 81.5%, P = 0.346). Auxiliary procedure rates were 4.8% (three patients) in DS-mini-PCNL group and 16.7% (nine patients) in VS-mini-PCNL group, with a significant difference (P = 0.034). The difference in the final stone-free rate between the two groups was rendered insignificant (93.8% vs. 89.1%, P = 0.510). CONCLUSIONS: DS-mini-PCNL is a safe and effective modality for large renal stones, which could increase the efficiency of stone extraction and decrease infectious complications compared with VS-mini-PCNL.

Efficacy and safety of modified tract dilation technique using simultaneous pulling of proximal and distal ends of a guidewire for percutaneous nephrolithotomy in modified supine position.

PURPOSE: Recently, the needs for supine percutaneous nephrolithotomy (PCNL) have become more increased because of an easy approach for endoscopic combined intrarenal surgery. However, making a nephrostomy tract during supine PCNL is more difficult than prone position due to movable kidney. To overcome this limitation, we used a modified nephrostomy tract dilation (MTD) technique using guidewire traction. MATERIALS AND METHODS: From January 2014 to June 2019, a total of 259 patients underwent PCNL in the modified supine position. Among them, the MTD technique was performed in 171 patients. For the MTD technique, two hydrophilic guidewires were passed from the nephrostomy tract and brought out through the urethra, then both proximal and distal ends were contralaterally pulled with tension for the easy placement of a fascia-cutting needle and a balloon catheter. We analyzed the efficacy of this technique in comparison with the conventional method. RESULTS: Intraoperative radiation exposure time (RET) (68.87 vs. 212.11 s) and hospital stay (5.90 vs. 6.74 days) were significantly shorter, while the success rate (77.2% vs. 63.6%) was significantly higher in the MTD group. Multivariate analysis showed that only the maximal stone diameter (odds ratio [OR], 1.928; 95% confidence interval [CI], 1.314-2.828; p=0.001) and MTD technique (OR, 0.017; 95% CI, 0.007-0.040; p<0.001) were independent factors for predicting short RET (<120 s). CONCLUSIONS: This study demonstrated that MTD technique can be effectively and safely performed in modified supine position PCNL, and it can be helpful in reducing RET and enhancing success rates.

Effect of Active Aspiration and Sheath Location on Intrapelvic Pressure During Miniaturized Percutaneous Nephrolithotomy.

OBJECTIVE: To evaluate the effects of location of the tip of percutaneous sheath and nephroscope in the collecting system together with active aspiration on the Intrapelvic pressure measurements (IPP) during miniaturized percutaneous nephrolithotomy (miniPNL). MATERIALS AND METHODS: The data of 20 patients underwent miniPNL in supine position was collected prospectively. IPP measurements were done with an 8 Fr urodynamic pressure measurement catheter in 4 different settings with respect to location of tip of sheath and nephroscope. All 4 settings were repeated with active aspiration. Totally measurements were done and compared in 8 different settings for 90 seconds in each patient. RESULTS: Highest mean IPP measurements were recorded in setting II (35.3 ± 11.8 cm H2O) where the sheath was located in the calyx and the tip of the nephroscope was in the renal pelvis. When active aspiration was applied, the mean pressure measurements were significantly lower than the counterpart settings without aspiration (all P values <.0001). When the active aspiration was applied, intrarenal pressure measurements did not exceed 40 cm H2O in any settings in any of the patients. CONCLUSION: Location of the tip of the sheath and the nephroscope has significant effect on IPP measurements. Active aspiration significantly lowers the IPP and keeps it <40 cm H2O. Endourologists should be aware of possible alterations in IPP during miniPNL and active aspiration should be kept in mind as an effective solution to decrease the risk of complications related to high IPP.

Can ultrasound guidance reduce radiation exposure significantly in percutaneous nephrolithotomy in pediatric patients?

In this study, we aimed to compare clinical and technical outcomes between pediatric patients who underwent percutaneous nephrolithotomy (PCNL) under fluoroscopy (FL) and those that underwent this procedure under FL with ultrasound assistance (FLUSA). The data of 66 PCNL patients were analyzed retrospectively. Renal puncture was successful in 22 patients in the FLUSA group and 44 patients in the FL group. In all cases, FL was used for tract dilation and confirmation of ureteral catheter positioning at the beginning of the procedure. The sample consisted of 46 males and 20 females with a mean age of 7.2 ± 2.1 years (range 1-17 years). Stone size varied from 8.0 to 75.4 mm, and 89% of patients achieved a completely stone-free state. The median puncture time was 130.5 ± 25.3 s for FLUSA and 295 ± 82.8 s for FL, the median fluoroscopic screening time was 95 ± 33 and 230 ± 116 s, respectively, and the median radiation dose was 19.04 ± 9.9 dGy/cm2 and 54 ± 21.4 dGy/cm2, respectively. The median puncture time, fluoroscopic screening time, and radiation dose were statistically lower in the FLUSA group (p = 0.001, Mann-Whitney U test). The greatest problem in PCNL is the use of fluoroscopy. Due to some anatomical differences from adults, applying PCNL in pediatric patients using only ultrasound may decrease the success rate. Puncture with ultrasound significantly reduces the radiation dose in children. Puncture with ultrasound and dilation under fluoroscopy is a successful and safe treatment method with low morbidity and high success rates and shorter hospital stay in pediatric patients.

Ultra-mini flexible percutaneous nephrolithotomy in the treatment of moderate-size kidney stones: a new instrument, a preliminary prospective study.

Ultra-mini PNL is increasingly preferred in the treatment of kidney stones. Unlike routine applications of the ultra-mini PNL technique, we aimed to perform kidney stones treatment with an epiduroscopic device that can pass through 11-13-Fr ureteral access sheaths with a flexible structure and which is routine in neurosurgical practice. The study was planned prospectively. The study included 52 patients with mid-sized kidney stones who had presented to our clinic between July 2017 and January 2019. The ultra-mini percutaneous nephrolithotomy was carried out with epiduroscopy routinely used in neurosurgery practice, which can pass through 11-13-Fr ureteral access and has a flexible structure. The perioperative and postoperative parameters were analyzed. The mean operation time was 45.6 ± 4.8 min and entry was provided through a single entry (from the calyx appropriate to the lower pole) in all patients; a second entry tract was not required. No DJ catheter or nephrostomy tube was installed in any patient and the procedures were completed totally without a tube. The mean reduction in hemoglobin values was determined as 0.33 (0.1-1.1) g/dL. None of the patients needed transfusion and no patient developed acute kidney injury. Clinically significant (≥ 3 mm) residual stone was observed in 2 (4%) of the 52 patients, while clinically insignificant (≤ 3 mm) stones were observed in 50 patients (96%). The mean length of hospital stay was 2.5 ± 0.9 days. Ultra-mini flexible percutaneous nephrolithotomy is an effective and safe method in the treatment of medium-sized kidney stones.

Vacuum-assisted mini-percutaneous nephrolithotomy: a new perspective in fragments clearance and intrarenal pressure control.

PURPOSE: To describe the vacuum-assisted mini-percutaneous nephrolithotomy (vmPCNL) technique performed via the 16Ch ClearPetra sheath, to evaluate its outcomes and to analyze intrarenal pressure (IRP) fluctuations during surgery. METHODS: Data from all consecutive vmPCNL procedures from September 2017 to October 2019 were prospectively collected. Data included patients' and stones characteristics, intra and peri-operative items, post-operative complications and stone clearance. Patients undergoing vmPCNL from March to October 2019 were submitted to IRP measurement during surgery. RESULTS: A total of 122 vmPCNL procedures were performed. Median stone volume was 1.92 cm3. Median operative time was 90 min and median lithotripsy and lapaxy time was 28 min. Stone clearance rate was 71.3%. Thirty-one (25.2%) patients experienced post-operative complications, seven of which were Clavien 3. Postoperative fever occurred in nine (7.4%) patients and one (0.8%) needed a transfusion. No sepsis were observed. IRPs were measured in 22 procedures. Mean IRP was 15.3 cmH2O and median accumulative time with IRP > 40.78 cmH2O (pyelovenous backflow threshold) was 28.52 sec. Maximum IRP peaks were reached during the surgical steps when aspiration is closed (mainly pyelograms), whereas during lithotripsy and suction-mediated lapaxy, the threshold of 40.78 cmH2O was overcome in three procedures. CONCLUSIONS: vmPCNL is a safe procedure with satisfactory stone clearance rates. Mean IRP was always lower than the threshold of pyelo-venous backflow and the accumulative time with IRP over this limit was short in most of the procedures. During lithotripsy and vacuum-mediated lapaxy, IRP rarely raised over the threshold.

Suction Use During Endourological Procedures.

PURPOSE OF REVIEW: Equipment used in endourology is constantly evolving due to increasing incidence of urolithiasis. Suctioning has been used mainly in PCNL in conjunction with ultrasonic and ballistic devices for stone removal. Recently technological advances permitted the use of suctioning in more endourological techniques. This review aims to summarize the literature regarding these advancements and analyze the upcoming results. RECENT FINDINGS: Several centers have conducted experimental and clinical studies on suctioning use during PCNL, mPCNL, and ureteroscopy and concluded that it is an effective and safe adjustment that improves stone-free rates and limits complication rates after these procedures. Suctioning use during common endourological procedures led to improved safety and efficacy among several indications. Due to the observational nature and small sample size of many studies, larger RCTs are needed to make safe conclusions.

SabreSource™: a novel percutaneous nephrolithotomy apparatus to aid collecting system puncture - a preliminary report.

BACKGROUND: Successful percutaneous nephrolithotomy (PCNL) relies on a technically challenging, precise needle puncture of the renal collecting system. We aimed to compare, in an ex vivo model, the use of a real time image guidance system (the SabreSource™) and a mechanical stabilising device with conventional manual techniques for the accuracy of needle placement. METHODS: The SabreSource™ system (Minrad International Inc.; New York, USA) is a real time image guidance system. The system platform is mounted on a C-arm fluoroscope. It employs targeting cross hairs on the fluoroscopic image that can be easily positioned to target the desired renal calyx. The system directs a visible laser beam onto the patient which is precisely aligned with the cross hairs on the fluoroscopic image. This provides the correct "bull's-eye" angle of approach to the calyx, even after the x-ray source is turned off. The locator then stabilises the needle in the "bull's-eye" position so that only screening for depth is required. Objective assessment using a simulated PCNL puncture was performed by 7 urologic trainees on a kidney phantom with and without using the SabreSource™. Fluoroscopy screening time (FST) and amount of radiation (mGy) used to achieve successful puncture were compared. RESULTS: Simulated PCNL puncture was quicker and resulted in reduced radiation exposure when the apparatus was used. The mean FST for traditional "bull's-eye" vs SabreSource™ puncture was 17 vs 5 seconds (p = 0.01), and the mean radiation exposure to puncture was 0.7 vs 0.2 mGy (p = 0.03), respectively. CONCLUSION: The SabreSource™ is a novel assistant to achieving successful PCNL puncture. In combination with "the locator" the preliminary in vitro testing suggests that the device reduces fluoroscopy exposure and is quicker. The device warrants further evaluation in the clinical setting.

Minimally Invasive Percutaneous Nephrolithotomy with a Novel Vacuum-assisted Access Sheath for obstructive calculous pyonephrosis ：A Randomized Study.

PURPOSE: To investigate the safety and efficacy of Minimally Invasive Percutaneous Nephrolithotomy (MPCNL) combined with Vacuum-assisted Access Sheath in the treatment of obstructive calculous pyonephrosis. MATERIALS AND METHODS: Seventy-six patients with obstructive calculous pyonephrosis, who were planned to receive MPCNL, were randomly divided into two groups. Group A was treated with Amplatz sheath combined with Cyberwand double probe ultrasound lithotripsy, and group B was treated with Vacuum-assisted Access Sheath (VAAS, ClearPetra, Well lead Medical) combined with holmium laser lithotripsy. The primary outcome was the operation successful rate. Other perioperative, and postoperative data such as operation time, stone free rate and complications were compared between groups. RESULTS: Single 20F access sheath was established in all cases. All patients underwent one-stage procedure. Compared with group A, group B had a higher initial stone-free rate (84.2% vs 63.1%, P= .037). The operation time of group B was 56.3 ± 19.83 min, significantly shorter than that of group A at 70.4 ± 14.83 min. The complication rate of B group was 15.8%, which was lower than that of group A (P= .035 ). Five patients (15.8 %) of group B had a postoperative fever (>38.5 ºC) (Clavien grade 2) that required additional antibiotics; whereas 8 patients (21.1 %) of group A (P= .361). There was no blood transfusion in group A, and one case in group B required transfusion. CONCLUSION: One-stage MPCNL combined with Vacuum-assisted Access Sheath and holmium laser lithotripsy is a simple, safe, effective, and ergonomically practical method for selected patients with obstructive calculous pyonephrosis.

Percutaneous nephrolithotomy: Three-needle technique on two planes. Cury's technique.

INTRODUCTION: Percutaneous nephrolithotomy is the main type of surgery indicated for kidney stones larger than 2 cm. The present study describes a three-needle technique for percutaneous nephrolithotomy on two planes. SURGICAL TECHNIQUE: The patient is first placed in the lithotomy position for cystoscopy, which guides the ureteral and urethral catheter. Next, the patient is placed in ventral decubitus for the three-needle technique. With the aid of the nephroscope, the first needle is positioned in the projection of the renal pelvis, the second needle is placed in the most posterior of the inferior calyces and the third needle is aligned with the other two at the most depressible point determined by the surgeon's index finger. After alignment in the topography of the third needle, an incision is made with the scalpel 1-2 cm perpendicular to the aponeurosis of the latissimus dorsi muscle. The second needle is replaced with a peridural needle, which is used to confirm the location of the inferior renal calyx and limit the depth of the Chiba needle inserted in the topography of the third needle, forming a 90° angle with the peridural needle. The Chiba needle enables the passage of the guidewire and subsequent dilatation until the 30F caliber for the passage of the Amplatz dilator, initiating the conventional procedure. COMMENTS: The technique described has been used at our service for 15 years and has the advantages of less morbidity, fewer complications and less use of the nephrostomy tube. The technique is also easy to learn and highly reproducible.

The Feasibility, Safety, and Efficacy of the Preemptive Indwelling of Double-J Stents in Percutaneous Nephrolithotomy Surgery: A Randomized Controlled Trial.

PURPOSE: The goal of this study is to compare the feasibility, safety, and efficacy of the preemptive indwelling of double-J stents (PI-DJS) versus the conventional preemptive indwelling of ureteral catheters (PI-UC) in percutaneous nephrolithotomy (PCNL) via a randomized, controlled clinical study. MATERIALS AND METHODS: A total of 75 patients with complex renal calculi underwent PCNL surgery and were randomized, using random number table, to receive either a PI-DJS (37 cases) or a PI-UC (38 cases). All operations were performed by the same experienced surgeon. Several outcomes were measured, including duration of operation, time to establish passage, level of hemoglobin decline, rate of stone clearance and incidence of complications. RESULTS: Guided by B-ultrasound, percutaneous passages were successfully established in all patients who then underwent one-stage PCNL. The time required to establish a passage using a PI-DJS was 7.5min, whereas that of the group who received a PI-UC was 11.5min (P < 0.01). There was no significant difference between the two groups in terms of operation duration, postoperative Hb decline rate, stone clearance rate, and perioperative complication incidences (all P > 0.05). CONCLUSION: PI-DJS during PCNL allowed for a reliable and stable reflux from the bladder into the renal pelvis to produce an artificial hydronephrosis without the formation of microbubbles, unlike conventional ureteral catheters.

Ultra-Mini-Percutaneous Nephrolithotomy for the Treatment of Upper Urinary Tract Stones Sized between 10-20 mm in Children Younger Than 8 Years Old.

PURPOSE: With the invention of miniature devices, it has been advised to apply less aggressive methods for the management of upper urinary tract stones, especially in children. In the recent years, ultra-mini percutaneous nephrolithotomy (UMP) has been used for the treatment of upper urinary tract stones in order to perform surgeries with less complications and more acceptable outcomes. Results reported from different medical centers have been promising. MATERIALS AND METHODS: Twenty-two children aged less than 8 years old with upper urinary stones sized between 10-20 mm underwent UMP. Inclusion criteria was solitary unilateral kidney stone, stone size between 10-20 mm, normal renal function tests, absence of any congenital malformations, and history of previous ESWL failure. Data including age, sex, side of kidney involvement, size of stone, location of stone, duration of surgery, duration of hospitalization, stone composition, need for blood transfusion, damage to adjacent organs, postoperative fever, septicemia after surgery, need for narcotics, further need for a complementary method, stone-free rate, pre and post-operative hemoglobin levels, and urinary leakage from the access tract were extracted from patients' medical files and were recorded. RESULTS: The mean age (± standard deviation) of children was 5.22 (±1.57) years. Fourteen (63.6%) patients were male. Fifteen (68.2%) renal stones were located in the right kidney, and 82% of patients had pelvis stones. 13 (59%) patients' stones were composed of calcium oxalate. Stone-free rate was 95.5%. In none of the cases urinary leakage, septicemia after surgery, injury to adjacent organs, and need for blood transfusions was reported. CONCLUSION: Ultra-mini percutaneous nephrolithotomy is an efficient and safe method for treating urinary stones sized between 10-20 mm in children.

Comparative Study of Percutaneous Tic Technique Vs Standard Percutaneous Nephrolithotomy.

OBJECTIVE: To compare the PERC-tic technique, described as placement of dual wires under fluoroscopic guidance adjacent to the stone within the obstructed calyx, to standard percutaneous nephrolithotomy (PCNL) with working wires secured down the ureter. MATERIALS AND METHODS: This is a retrospective cohort study of patients who underwent a PCNL procedure between October 2016 and November 2018. Patients undergoing the PERC-tic technique were compared to patients undergoing standard PCNL. Regression models evaluated if PERC-tic PCNL was associated with equivalent stone-free rates to standard PCNL at 90 days, need for secondary procedures, and 90-day hospital readmission. RESULTS: This study involved 126 PCNL cases of which 63 were done using the PERC-tic technique and 63 with standard PCNL. In multivariate analysis, there was no statistical difference in 90-day stone-free rate between standard PCNL and PERC-tic cohorts (P = .08). We did note a 6 times higher likelihood of needing secondary procedures for residual stones in the PERC-tic vs standard PCNL groups (71% vs 30% P <.0001). There was no statistical significance in 90-day hospital readmission rates between groups (P = .47). CONCLUSION: Our findings suggest similar stone-free rate at 90 days and higher rates of secondary procedures after PERC-tic PCNL compared to the standard approach; however, there was no difference in complications. These findings may reflect decreased visualization with the PERC-tic technique or simply be reflective of the case difficulty requiring the use of the PERC-tic technique. These findings can be used for patient counseling when considering this technique for complex stone disease.