Conventional PCNL Research Articles

Mini-Perc for Renal Stones-A Single Center Experience and Literature Review.

The aim of this study was to analyze the outcomes of miniaturized nephrolithotomy (mini-perc) in the management of renal stones with a diameter smaller than 20 mm. We retrospectively reviewed the records of 102 patients who underwent mini-perc between March 2015 and March 2020 in our department. The primary objective was the stone-free rate, but we also analyzed the retreatment rate, complications, hospital stay, operative time and reduction in hemoglobin level. All these patients had this technique as their first-line treatment, in a prone position, using a 16 Fr sheath size. Data were compared to a series of patients from the literature, treated with conventional PCNL. The patients had calculus limited to either a single calyx or just extending to the renal pelvis, and stone size was less than 20 mm in its maximal dimension. The intrarenal stone location was in the upper calyx in 7 cases, middle calyx in 20 cases and lower calyx in 46 cases, and there were 29 patients with renal pelvis stone. The male to female ratio was 1.5:1, and the median age was 48.4 years. The average stone size was 17.4 mm in diameter (ranging between 9 and 20 mm) and all cases underwent Ho-YaG laser lithotripsy, ballistic energy and combined ultrasonic and ballistic lithotripsy. At the end of the procedure, an antegrade double J stent was placed under fluoroscopy for a maximum of 2 weeks in 42 cases, while 9 cases needed a nephrostomy tube 12-14 F. A total of 51 cases were totally tubeless. Our median operative time was 61 min (ranging from 35 to 75 min). The median hospitalization stay was 3.8 days. The stone free rate was 90.1% after one procedure, only nine (8.8%) cases needed a "second look" flexible ureteroscopy, and the final stone-free rate was 98% (absence of detectable calculi on ultrasound, KUB or non-contrast CT scan). The overall complication rate was 6.86% (Clavien classification I-57.14%; II-28.5%; III-14.2%), while no Clavien IV or V complications were reported. No patient required a blood transfusion, and mean hemoglobin loss was 0.81 mg/dL. Overall, our results are better than similar data for conventional PCNL in the literature. The "mini-perc" technique is an effective procedure for the treatment of the renal lithiasis that is less or equal to 2 cm. The results demonstrated that this minimally invasive technique is associated with a higher stone-free rate and minimal complications.

Comparison of stone clearance rate and need of nephrostomy in conventional versus mini percutaneous nephrolithotomy.

Background: The increased renal stone size affects the stone clearance rate and the need for nephrostomy in (Percutaneous nephrolithotomy) PCNL. Also, complete stone clearance of bulky renal calculi causes blood loss during PCNL, resulting in hemoglobin drop and sometimes requiring transfusion. This is a frequently encountered phenomenon and is quite problematic for urologists and patients. This study aimed to determine the rate of stone clearance and nephrostomy needed in Mini-PCNL over Conventional PCNL.
 Methodology: A comparative study was conducted at the urology department of PIMS, Islamabad. A total of eighty (n=80) adult patients of either gender between ages 18-65 years were enrolled. Subjects enrolled had radiographic evidence of renal stones of > 1cm. Group A patients underwent conventional PCNL procedures, and Group B patients underwent Mini PNCL. The rates of stone clearance nephrostomy needed were compared between the two study groups. 
 Results: The mean age of study participants in group A was (33.7 ± 12.1) and in group B (36.5 ± 11.1). The mean sizes of the stone were 2.4 cm and 2.7 cm in groups A and B, respectively. X-rays were used to assess the stone clearance rate on the first operative day in both study groups. Stones were cleared in group-A at 87.5% (n=35) and in group B at 82.5% (n=33). Nephrostomy was needed in group A at 50.0% (n=20) and in group B at 47.5% (n=19). 
 Conclusion: The stone clearance rate and the need for a nephrostomy tube were nearly similar in both intervention groups.

Intrarenal pressures during percutaneous nephrolithotomy: a porcine kidney model

Background Increased intrarenal pressure during endoscopic lithotripsy is associated with increased adverse outcomes. The objective of this study was to evaluate the effect of various devices on IRP during percutaneous intrarenal surgery in ex vivo porcine kidney models. Methods Whole intact porcine urinary tracts were harvested. Intrarenal pressure was measured using cystometrometry software. Intrarenal pressure during PCNL was recorded using variations of percutaneous access sheath size, irrigation height of 100 cm and 60 cm, use of a ureteric catheter and use of suction. The primary outcome was absolute IRP measurements. Secondary outcomes were comparisons of IRP between techniques. Results Using a 30 Fr vs 26 Fr access sheath and 26 Fr nephroscope the mean pressure at an irrigation height of 60 cm was significantly lower than 100 cm (p = 0.0013 vs p < 0.0001, respectively). Pressure’s during mini-PCNL were significantly higher than conventional PCNL in all variations. Using the 16.5 Fr access sheath and 12 Fr nephroscope produced a significantly lower pressure at a 60 cm irrigation height than 100 cm (p = 0.0010). IRP was significantly lower with a ureteric catheter in place vs no ureteric catheter at 100 cm (p = 0.0015) and at 60 cm (p = 0.0040). Conclusions Using standard PCNL tract sizes intrarenal pressure varied significantly depending on the height of the irrigation fluid. Mini-PCNL is at higher risk of pathological pressure, however, the use of a ureteric catheter significantly decreased pressure. To maintain safe IRP during PCNL urologists should be aware of these significant variations.

A randomized study comparing conventional percutaneous nephrolithotomy versus check pyeloscopic percutaneous nephrolithotomy.

Objective:The objective of this study is to compare the advantages of check-pyeloscopic percutaneous nephrolithotomy (CP-PCNL) over conventional PCNL (C-PCNL) in the management of renal calculi.Materials and Methods:All patients with renal calculi requiring PCNL who attended the department of urology in a tertiary care center from December 2016 to October 2018 were included in the study. The patients were randomized into two groups of 50 each. Each group underwent PCNL in a conventional or check pyeloscopic method, respectively.Results:A total number of complications were more in C-PCNL group comprising of two pelvic tears, 8 infundibular tears, 1 minor urothelial injury, 2 cases of bleeding lasting for more than 24 hours, while in CP-PCNL group, complications were less (comprising of 1 minor urothelial injury and 1 case of infundibular tear). Statistical analysis was used to compare both the groups, and the results were statistically significant (P = 0.027).Conclusion:Check pyeloscopy at the time of PCNL is a safe, effective, and economical technique. This study shows that the complications such as blood loss, urothelial injury, and postoperative pain are less when check pyeloscopy is done during PCNL.

UP15 - A new device for lithoextraction during conventional PCNL

UP15 - A new device for lithoextraction during conventional PCNL

P081 - A comparative evaluation of conventional PCNL and mini-PCNL adopting middle calyx approach into pelvicalyceal system: A perspective of stone clearance

P081 - A comparative evaluation of conventional PCNL and mini-PCNL adopting middle calyx approach into pelvicalyceal system: A perspective of stone clearance

V01-11 THULIUM SUPERPULSE FIBER LASER (TSPFL) MICRO-PCNL: HOW TO IMPROVE STONE-FREE RATE (SFR)

INTRODUCTION AND OBJECTIVES:Conventional PCNL has been commonly used for large kidney stones for a long time. New possibilities of minimally invasive operative techniques emerged with technological...

Complete Ultrasound-guided Percutaneous Nephrolithotomy in Prone and Supine Positions: A Randomized Controlled Study

ObjectivesTo evaluate the safety, efficacy, adverse events, and feasibility of ultrasound guided percutaneous nephrolithotomy (US-PCNL) in the management of large renal stones in supine and prone positions and to point out the practical considerations related to these techniques in comparison with standard PCNL. Patients and methodsThis study was conducted between August 2013 to September 2018 as a prospective randomized and controlled study. A total of 392 consecutive patients with nephrolithiasis >2 cm were randomly assigned to undergo ultrasound PCNL in prone (P-US-PCNL) (132 patients); supine position (S-US-PCNL) (129 patients) or conventional PCNL (C-PCNL) (131 patients). The preoperative parameters, the intraoperative findings, operative time, hospital stay, perioperative morbidities, stone free rate, and related data were recorded. ResultsThe demographic and the baseline characteristics were comparable in all study groups. The mean number of trails and time for successful puncture in P-US-PCNL, S-US-PCNL, and C-PCNL were 1.9 ± 1, 2.3 ± 1.2, and 1.7±1, respectively (P < .001), and 15.8 ± 5.8, 19.3 ± 9.4, and 16.5 ± 8.1 seconds, respectively (P < .001). The operation time was 69 ± 22, 75 ± 23, and 72 ± 27 minutes, respectively, (P > .05). The mean nephrostomy time and length of hospital stay were 3 ± 1.3, 3.4 ± 1.5, 3.2 ± 1.2 hours, respectively, and 3.8 ± 1.5, 4.1 ± 1.5, 3.9 ± 1.3 days, respectively (P > .05). The mean percentage decrease in hemoglobin concentration was 1.65 ± 0.66, 1.77 ± 0.78, and 2.1 ± 0.9, respectively (P < .001), overall stone clearance was 88%, 79%, and 85%, respectively (P > .05). Complications were acceptable and similar between groups. ConclusionUS-PCNL either in prone or supine position is as effective, feasible, and safe as C-PCNL with zero radiation exposure.

Tubeless percutaneous nephrolithotomy, are there any real benefits?

Aims & objectives: To assess the benefits of Tubeless PCNL [T PCNL] with regard to cost, tolerability over conventional PCNL [C PCNL]. Materials and Methods: This prospective study included patients undergoing Percutaneus nephrolithotomy during a period between 2007 to 2017. The selection criteria for placing the patient in tubeless arm were - Maximum stone burden of 3 cm; Single access tract; Minimal or negligible hemorrhage during the procedure; Operative time of less than two hours; lack of collecting system perforations; clinically insignificant residual fragments. In those who met the criteria antegrade stenting was done without a nephrostomy. In those patients, who did not full fill the inclusion criteria, a 24 F Nephrostomy tube was placed at the end of procedure. Results: The study cohort included 373 patients consisting of 211 males and 162 females in 3rd to 5th decades of their lives. Those under T PCNL and C PCNL arms were 301 and 72 respectively. The stone size varied from 17-27 mm with a mean of 22 mm. The procedure time varied between 35 to 97 minutes with a mean of 66 minutes. The T PCNL arm was analyzed with regard to Analgesic requirement; Duration of hospital stay and the total cost of the treatment and compared with those under C PCNL. Patients under had their catheter removed on 2nd postoperative day and discharged on the same day afternoon if the operative site did not develop any leak. For those under C PCNL, Nephrostomy was clamped at 48hrs if the drainage was clear and X KUB did not show any significant residual fragments. Re look procedure was planned if there bigger residual fragments. The pain was assessed using visual analogue scale (VAS) at 6, 12 & 24 hrs. Post procedure and analgesia was administered as per requirement. Majority of patients (90.7%), under T PCNL rated their pain perception highest (4-6) at 6 hrs., which came down to 2-4 at 12 hrs. They did not need any analgesia at 24 hrs., rating their pain at 1-2. mean of 3.9. The same under C PCNL was higher at 8-9 on VAS at 6 hrs, 6-8 at 12 hrs and 4-6 at 24 hrs. Parenteral Diclofenac the drug of choice for pain relief and the mean analgesic requirement was 75 mg of Diclofenac. The Analgesic requirement was higher under C PCNL arm. None required blood transfusion as the fall in hematocrit was negligible under T PCNL. The mean hospital stay in those who underwent T PCNL was 3 days as compared to 5 days under C PCNL. Conclusion: Tubeless PCNL offers a significant benefit in terms of lesser analgesic requirement, shorter hospital stay but necessitates an additional procedure with cost in stent removal. By using stents with setons might obviate stent removal and hence the cost.

A non-inferiority study to analyze the safety of totally tubeless percutaneous nephrolithotomy

Totally tubeless percutaneous nephrolithotomy (ttPCNL) becomes increasingly frequently utilized in the treatment of kidney stones. This procedure emerged as an answer for patients' needs to minimize hospitalization time, pain intensity and discomfort due to nephrostomy tube. However, ttPCNL may be less safe for patients, as without nephrostomy tube bleeding from renal vessels is potentially more severe. The purpose of our study was to retrospectively evaluate the safety parameters of ttPCNL collected in a prospective manner. This was a single tertiary care center, non-inferiority study with 2 arms (55 patients in each arm). The 1st group consisted of patients who underwent ttPCNL with the application of TachoSil® (Takeda, Osaka, Japan) as sealing material, while in the 2nd group, conventional PCNL with nephrostomy tube (cPCNL) was utilized. The primary goal was to prove that hemoglobin drop after surgery, as equivalent of safety, was not inferior than 1 g/dL. The secondary endpoints comprised visual analogue scale (VAS) of pain, additional pain treatment and hospital stay. The mean hemoglobin drop after ttPCNL was insignificantly lower in comparison with cPCNL group (mean: -0.35 g/dL; confidence interval (CI) = -0.8, 0.21). Visual analogue scale of pain and pain treatment were comparable between groups. Hospital stay was significantly shorter in the ttPCNL group. Totally tubeless PCNL can be considered a safe option after uncomplicated lithotripsy - what is important, it is characterized by a shorter hospitalization time. Postoperatively, pain intensity is comparable between both groups.

V37 - The new device for lithoextraction during conventional PCNL

V37 - The new device for lithoextraction during conventional PCNL

Miniaturisation of PCNL.

Conventional PCNL leads to a high stone-free rate but is associated with a significant treatment morbidity. To decrease the morbidity of PCNL but to achieve an equal stone-free rate, in 2001 a miniaturised version of a conventional PCNL (Mini-PCNL) was introduced. Meanwhile numerous modifications of the Mini-PCNL were reported. The ongoing experience with the Mini-PCNL technique showed that Mini-PCNL is not only a miniaturisation but also a different method to remove the stones, as the stones come out of the calyceal system only by means of the irrigation flow without any further need of forceps or baskets. Due to a limited number of papers in the literature, the guidelines so far do not distinguish between conventional and Mini-PCNL, although the Mini-PCNL already became a frequent treatment modality in daily routine worldwide. From the current point of view, Mini-PCNL can be recommended to treat all kinds of upper urinary tract stones exceeding a diameter of 10mm. In this context, Mini-PCNL is a treatment alternative to flexible ureterorenoscopy, SWL and conventional PCNL. The available literature shows that the morbidity of Mini-PCNL is less and the stone-free rate is equal to that of conventional PCNL. It seems that there is no limitation to Mini-PCNL in the treatment of upper urinary tract stones. The future will show what kind of further miniaturisation of the Mini-PCNL procedure will be appropriate.

PERCUTANEOUS REMOVING OF KIDNEY STONE UNDER ONLY ULTRASONIC CONTROL

The study included the outcome of percutaneous treatment for nephrolithiasis in 176 patients, who were divided in two groups. Ninety patients (Group 1) underwent PNCL with combined ultrasound and radiological guidance, 86 patients (Group 2) underwent surgery with only ultrasound guidance. The inclusion criteria were the cases with renal pelvis stones larger than 2,0 cm diameter. Postoperative complications (exacerbation of chronic pyelonephritis, macrohematuria) were observed in 13 (14,4%) patients in Group 1 and in 6 (7,0%) in Group 2. There was no significant differences in effectiveness of PCNL, the volume of blood loss and duration of hospitalization. In Group 1 and Group2 the effectiveness of PCNL was 94,4% and 93,0% respectively. In Group 1, 5 (5,6%) required additional intervention. In Group 2, 6 (7,0%) patients required additional intervention. The efficiency of ultra- sound guided PCNL is comparable with this of conventional PCNL. In addition, the radiation exposure of patients and medical staff is reduced during ultrasound guided PCNL.

Mini PCNL for renal calculi: does size matter?

To evaluate the minimally invasive percutaneous nephrolithotomy (MIP) system for renal calculi. Consecutive patients undergoing mini-percutaneous nephrolithotomy (mPCNL) procedures with the MIP system were enrolled. Patient position, American Society of Anesthesiologists classification, puncture location, stone clearance, postoperative drainage and complications were recorded, and features unique to MIP were noted. In all, 30 patients underwent 32 mPCNL procedures. The mean stone size was 17 (10.75-21.25) mm and the mean number of stones was 1 (1-2). The median stone clearance rate was 96.5 (95-100)%. The complication rate was 9.3%. No patient required a transfusion. In addition to these outcomes, we noted that the MIP system has many advantages over conventional PCNL (cPCNL). It is easy to learn and can be performed in both supine and prone positions. It is safe for supracostal puncture, provides excellent access to nearly all calyces and upper ureter, has multiple stone treatment options, can be used as an adjunct to cPCNL, and can be performed as a tubeless procedure. Our experience with the MIP system has shown several advantages over cPCNL. mPCNL with the MIP system has several features that suggest it should be considered as an alternative or adjunct to cPCNL, ureteroscopy and extracorporeal shockwave lithotripsy.

The hydrodynamic basis of the vacuum cleaner effect in continuous-flow PCNL instruments: an empiric approach and mathematical model.

Passive removal of stone fragments in the irrigation stream is one of the characteristics in continuous-flow PCNL instruments. So far the physical principle of this so-called vacuum cleaner effect has not been fully understood yet. The aim of the study was to empirically prove the existence of the vacuum cleaner effect and to develop a physical hypothesis and generate a mathematical model for this phenomenon. In an empiric approach, common low-pressure PCNL instruments and conventional PCNL sheaths were tested using an in vitro model. Flow characteristics were visualized by coloring of irrigation fluid. Influence of irrigation pressure, sheath diameter, sheath design, nephroscope design and position of the nephroscope was assessed. Experiments were digitally recorded for further slow-motion analysis to deduce a physical model. In each tested nephroscope design, we could observe the vacuum cleaner effect. Increase in irrigation pressure and reduction in cross section of sheath sustained the effect. Slow-motion analysis of colored flow revealed a synergism of two effects causing suction and transportation of the stone. For the first time, our model showed a flow reversal in the sheath as an integral part of the origin of the stone transportation during vacuum cleaner effect. The application of Bernoulli's equation provided the explanation of these effects and confirmed our experimental results. We widen the understanding of PCNL with a conclusive physical model, which explains fluid mechanics of the vacuum cleaner effect.