Learning curve of ultrasound-guided percutaneous nephrolithotripsy in the treatment of complex renal calculi

OBJECTIVE

This study was performed to investigate the learning curve of ultrasound-guided percutaneous nephrolithotripsy (PCNL) for the treatment of complex renal calculi.

METHODS

Seventy-two patients with complex renal stones who underwent ultrasound-guided PCNL by the same operator from November 2016 to September 2020 were retrospectively analyzed. The learning curve of PCNL for complex renal stones was analyzed using multifactorial cumulative sum (CUSUM) analysis and best-fit curves.

RESULTS

The CUSUM best-fit curve peaked at Case 36, which represented the minimum number of cumulative cases required to cross the learning curve for this surgical procedure. Accordingly, the learning curve was divided into a learning improvement period (36 cases) and a proficiency phase (36 cases). Compared with the learning improvement period, the proficiency phase was characterized by a shorter puncture time and operation time, a smaller drop in the hemoglobin level, and a lower postoperative complication rate.

CONCLUSION

The learning curve of PCNL for the treatment of complex renal calculi can be divided into a learning improvement period and a proficiency phase, and the minimum cumulative number of cases is 36.

Post-operative pain following percutaneous nephrolithotripsy- clinical correlates

OBJECTIVES

Management of postoperative pain following percutaneous nephrolithotripsy (PCNL) is a significant goal. We sought to identify risk factors and clinical correlates of postoperative pain in order to improve perioperative management and patient satisfaction.

MATERIALS AND METHODS

A single-center, retrospective analysis, from a prospectively maintained database, of all consecutive patients who underwent PCNL for renal calculi between January 2011 and August 2018. Postoperative pain was assessed using the visual analog scale (VAS) and analgesic use. We considered VAS score above 4 as meaningful. Pain management was standardized according to patirnt reported VAS scores. Multivariable logistic regression was performed to identify risk factors and clinical correlates.

RESULTS

A total of 496 patients were analyzed. Younger age was associated with VAS above 4 on the operative day and the first postoperative following PCNL (p = 0.003 and p < 0.001, respectively). Female gender was associated with VAS above 4 in the first 2 days following the operation (p < 0.001).

CONCLUSIONS

Younger age and female gender would most likely benefit from pre-emptive improved pain management protocols following PCNL.

Assessment of single-probe dual-energy lithotripters in percutaneous nephrolithotomy: a systematic review and meta-analysis of preclinical and clinical studies

PURPOSE

To evaluate the safety and efficacy of single-probe dual-energy (SPDE) lithotripters in patients undergoing percutaneous nephrolithotripsy (PCNL) through a systematic review and meta-analysis.

METHODS

We searched PubMed, Cochrane Library, Scopus and Embase databases until July 2022 for any preclinical or clinical studies, exploring the safety and efficacy of different SPDE lithotripters in patients undergoing PCNL. We performed a meta-analysis to compare stone-free rate, bleeding, or other complications and mean operative time between SPDE lithotripters and other lithotripters (PROSPERO: CRD42021285631).

RESULTS

We included 16 studies (six preclinical, seven observational and three randomized with 625 participants) in the systematic review and four in the meta-analysis. Preclinical studies suggest that SPDE lithotripters are safe and effective for the management of renal stones. Among clinical studies, four studies assessed Trilogy with no comparative arm, two compared Trilogy or ShockPulse with a dual-probe dual-energy lithotripter, two compared Trilogy with a laser, one compared ShockPulse with a pneumatic lithotripter, and one directly compared Trilogy with ShockPulse. Comparing SPDE lithotripters to other lithotripters, no significant differences were demonstrated in stone free rate (OR 1.13, 95% CI 0.53-2.38, I² = 0%), postoperative blood transfusion (OR 1.33, 95% CI 0.34-5.19, I² = 0%), embolization (OR 0.45, 95% CI 0.02-12.06), operative time (WMD: 2.82 min, 95% CI -7.31-12.95, I² = 78%) and postoperative complications based on the Clavien-Dindo classification.

CONCLUSIONS

SPDE lithotripters represent a promising treatment modality for patients requiring PCNL. Despite the initial encouraging findings of preclinical and isolated clinical studies, it seems that Trilogy or ShockPulse provide similar efficiency compared to older generation devices.

Endoscopic combined intrarenal surgery for renal allograft lithiasis using "sheath-connection technique": A case report

A 66-year-old man was diagnosed with renal allograft lithiasis. Although retrograde intrarenal surgery was attempted, a ureteral access sheath (UAS) was difficult to insert. Subsequently, we planned the endoscopic combined intrarenal surgery (ECIRS) using the "Sheath-connection technique." We indwelled the two UAS anterogradely and retrogradely, unified them at the bladder and the junction of the two UAS was passed through the ureterovesical junction. We successfully performed ECIRS.

Calyceal Diverticula Disease: Diagnosis and Management Options in the Era of Non-Contrast CT Scan

INTRODUCTION

Calyceal diverticula (CD) are traditionally diagnosed by contrast studies. However, non-contrast CT is the standard imaging modality for kidney stones. Therefore, we aimed to determine if the lack of contrast imaging affected outcomes of the management of symptomatic CD with stone.

MATERIALS AND METHODS

This is a retrospective study of patients diagnosed with CD with intracalyceal stone from 2000 to 2017 analyzing demographics, clinical data, and success of different treatment options. The timing of CD diagnosis is correlated to the success of the first treatment.

RESULTS

Forty-eight patients were found. CD was diagnosed prior to intervention in 20 (42%) cases and intraoperatively during flexible ureteroscopy in 17 (35%) and 11 (23%) cases were diagnosed after failed intervention, mainly ESWL. We found that the success rate of treatment was highly affected by the timing and modality of diagnosis. Preoperative diagnosis of CD was associated with 69% success rate of the first intervention. In contrast, there was a 0% success rate of first treatment if CD was not diagnosed with contrast imaging. Furthermore, univariate analysis showed no significant association between sociodemographics and clinical variables and success treatment (p > 0.05).

CONCLUSIONS

The delay in diagnosing CD with stone contributes significantly to the success rate and the number of treatments.

Clinical efficacy of enhanced recovery after surgery in percutaneous nephrolithotripsy: a randomized controlled trial

BACKGROUND

To evaluate the feasibility, safety, applied value and efficacy of enhanced recovery after surgery (ERAS) for PCNL for the treatment of renal calculi. Although the ERAS is applied for many urological diseases, its application in percutaneous nephrolithotripsy (PCNL) is still limited.

METHODS

This was a prospective study of patients admitted to hospital January and December 2018 and who were only diagnosed with renal calculi and excepted for serious or uncontrollable basic diseases and patients with multiple operation history and medication history. Patients were randomized 1:1 to the ERAS and traditional operation groups starting on the day before operation and end on the day of discharge. Each group was 118 cases. The stone clearance rate, visual analogue scale (VAS) pain score, the occurrence of perirenal hematoma and effusion, the incidence of extravasation of urine, the incidence of fever, bleeding and blood transfusion, and postoperative hospital stay were observed.

RESULTS

The stone clearance rates were similar between the two groups (ERAS: 93.2% (109/117) vs. traditional: 89.8% (106/118), P = 0.800). The operation time was similar in the two groups (ERAS: 54 ± 12 vs. traditional: 58 ± 11 min, P = 0.656). VAS pain score that was 0.79 ± 0.76 in the ERAS group at 4 h after surgery and was significantly lower than 2.79 ± 0.98 in the traditional group (P < 0.0001). The total complication rate was 15 cases in the ERAS group and 22 cases in the traditional group (P = 0.573). There were no difference in costs (21,348 ± 2404 vs. 21,597 ± 2293 RMB, P = 0.529).

CONCLUSIONS

ERAS perioperative management in PCNL was feasible, was without additional complications, and had well economic and social benefits. It is worth of clinical promotion and application.

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.

Thulium-fiber laser for lithotripsy: first clinical experience in percutaneous nephrolithotomy

PURPOSE

To evaluate the efficacy and safety of thulium-fiber laser (TFL) in laser lithotripsy during percutaneous nephrolithotomy (PCNL).

METHODS

Patients with stones < 30 mm were prospectively recruited to undergo PCNL using TFL "FiberLase" (NTO IRE-Polus, Russia). Stone size, stone density, operative time, and "laser on" time (LOT) were recorded. Study included only cases managed with fragmentation. Stone-free rate and residual fragments were determined on postoperative computer tomography. Complications were classified using the Clavien-Dindo grade. Stone retropulsion and endoscopic visibility were assessed based on surgeons' feedback using a questionnaire.

RESULTS

A total of 120 patients were included in the study with a mean age of 52 (± 1.8) years; of these 77 (56%) were males. Mean stone size was 12.5 (± 8.8) mm with a mean density of 1019 (± 375) HU. Mean operative time was 23.4 (± 17.9) min and mean LOT was 5.0 (± 5.7) min. Most used settings were of 0.8 J/25-30 W/31-38 Hz (fragmentation). The mean total energy for stone ablation was 3.6 (± 4.3) kJ. Overall stone-free rate was 85%. The overall complication rate was 17%. Surgeons reported stone retropulsion that interfered with surgery in 2 (1.7%) cases insignificant retropulsion was noted in 16 (10.8%) cases. Poor visualization was reported in three (2.5%) cases and minor difficulties with visibility in four (3.3%) cases.

CONCLUSIONS

TFL is a safe and effective modality for lithotripsy during PCNL and results in minimal retropulsion.

Robustness of Textural Features to Predict Stone Fragility Across Computed Tomography Acquisition and Reconstruction Parameters

RATIONALE AND OBJECTIVES

Previous studies have demonstrated that quantitative relationships exist between stone fragility at lithotripsy and morphological features extracted from computed tomography (CT) scans. The goal of this study was to determine if variations in scanner model, patient size, radiation dose, or reconstruction parameters impact the accuracy of the prediction of renal stone fragility in an in vitro model.

MATERIALS AND METHODS

Sixty-seven kidney stones were scanned using routine single and dual energy stone protocols, mimicking average, and large patient habitus. Low dose scans were also performed. Each scan was reconstructed with routine protocol parameters, and with thinner (0.6 mm) or thicker (3 mm) images, two different reconstruction kernels, and iterative reconstruction at two strengths. Fragility of each stone was measured in a controlled ex vivo experiment. A single predictive model was developed from a reference CT protocol configuration and applied to data from each CT acquisition and reconstruction parameter tested to obtain estimated stone comminution times.

RESULTS

None of the investigated protocols showed a significant variation in the accuracy of stone fragility classification, except for the ones with the most aggressive iterative reconstruction and/or with thicker images. In these protocols, a number of stone fragility assessments changed from fragile to hard (or vice versa), compared to their ground truth measurement.

CONCLUSION

Prediction accuracy of stone fragility models developed from CT data is robust to expected variations in CT stone protocols used for quantification tasks. This finding facilitates their future adoption to different clinical practices.

Comparison between percutaneous nephrolithotomy and flexible ureteroscopy for the treatment of 2 and 3cm renal lithiasis

CONTEXT AND OBJECTIVES

The first-line treatment for >2cm lithiasis is percutaneous nephrolithotomy (PNL), leaving flexible ureteroscopy (fURS) as a second option. In the present review, the stone-free rate and the complications of both techniques were evaluated in the treatment of 2-3cm stones.

MATERIAL AND METHODS

Systematic review of studies that compared both techniques. Studies that were not comparative, as well as those carried out in the pediatric population or with <2cm or>3cm stones, were excluded. Two researchers independently performed the investigation, obtaining 5 studies that made up a total of 815 patients: 252 belonged to the fURS group and 563 to the PNL group. Four studies were retrospective, and one was non-randomized prospective.

RESULTS

Stone-free rate ranged between 47.0% and 95.0% for the fURS and between 87.0% and 100% for the PNL. The complication rate was 8.8-29.0% in the fURS and 11.9-27.0% in the PNL. fURS required a greater number of procedures, and had a lower decrease in haemoglobin and creatinine rise compared to PNL.

CONCLUSIONS

The stone-free rate was higher for PNL, although the fURS could reach comparable results at the expense of performing several procedures. Both techniques have a similar frequency of complications, but the PNL has more postsurgical analytical alterations.

Retrograde intrarenal surgery vs miniaturized percutaneous nephrolithotomy to treat lower pole renal stones 1.5-2.5 cm in diameter

AIM

To compare the outcomes of retrograde intrarenal surgery (RIRS) and miniaturized percutaneous nephrolithotomy (mini-PCNL) in treating lower pole (LP) renal stones with a diameter of 1.5-2.5 cm.

METHODS

A total of 216 patients who underwent mini-PCNL (n = 103) or RIRS n = 113) for LP stones with a diameter of 1.5-2.5 cm were enrolled between December 2015 and April 2017 at the Urology Department of Ningbo Urology and Nephrology Hospital.

RESULTS

Significant differences were found in the hospital stay (9.39 ± 4.01 vs 14.08 ± 5.26, P < 0.0001) and hospitalization costs (2624.5 ± 513.36 vs 3255.2 ± 976.5, P < 0.0001) between the RIRS and mini-PCNL groups. The mean operation time was not significantly different between the RIRS group (56.48 ± 24.77) and the mini-PCNL group (60.04 ± 30.38, P = 0.345). The stone-free rates at the first postoperative day (RIRS vs mini-PCNL: 90.2% vs 93.2%, P = 0.822) and the second month postoperatively (RIRS vs mini-PCNL: 93.8% vs 95.1%, P = 0.986) were not significantly different.

CONCLUSION

RIRS and mini-PCNL are both safe and effective methods for treating LP stones with a diameter of 1.5-2.5 cm. RIRS can be considered as an alternative to PCNL for the treatment for LP stones of 1.5-2.5 cm.

[Clinical analysis for preset double J tube in percutaneous nephrolithotripsy]

Objective: To evaluate the clinical application and effect of preseting Double-J ureteric stent in percutaneous nephrolithotripsy. Method: 74 cases of renal calculi treated with PCNL in our hospital during June 2014 to February 2017 were retrospectively analyzed. Of 74 cases, 54 was male, 20 was female. All cases were aged 27 to 78, the mean age was (49.5±12.3) years old. The diameter of the stone was 20 to 59 mm, and the mean diameter was of (29.4±4.3) mm.Our Surgical methods was first putingFr6 double J tube in abnormal ureteral in advance in lithotomy position, then indwellingthree-way Foley catheter and clipping drainage port, perfusingirrigation port with 3 000 ml saline from 60-80 cm height.Perfusingsaline through irrigation port in prone position, we produce artificial hydronephrosis, then indwelling channel Fr20 through B ultrasound guided percutaneous nephrostomy, and removing renal calculi using holmium laser lithotripsy. Results: All patients were successfully completed percutaneous nephrostomy and indwell Fr20 channel, mean channel set up time (8.0 ±2.0) min, mean operation time (79±46) min, mean decline of hemoglobin (17.0±4.0) g/L, mean serum creatinine increased(3.1±1.1) μmol/L, one-stage stone-free rates 81.1%, complication rate 8.1% (1 case injured pleura and suffered from pneumothorax, 1 case suffered from massive hemorrhage of renal arteriovenous fistula after operation, 4 cases suffered postoperative fever). Conclusion: Advance in percutaneous nephrolithotripsy indwelling double J tube is a safe and feasible method, which is advantageous to the percutaneous renal puncture and the establishment of channels, and can avoid the blindness of along the line of indwelling double J.

Laparoscopic Assisted Transmesocolonic Percutaneous Nephrolithotripsy in Ectopic Iliac Kidney

We report a case of 15-year old female who presented with recurrent lower abdominal pain treated three times with ESWL previously. She was diagnosed as having right ectopic kidney with a 4 cm renal stone in renal pelvis and involving lower and mid calyx. She was treated successfully with laparoscopic assisted transmesocolonic percutaneous nephrolithotripsy. Procedure resulted in complete stone clearance without any perioperative or post operative complication. Patient stayed in hospital for 72 h with no drains or stents after day 5, post operatively.

Modular training for percutaneous nephrolithotripsy: The safe way to go

Objectives should be describe a modular training scheme (MTS) which aims to provide training in percutaneous nephrolithotripsy (PCNL) and ensure the safety of the patients.

Subjects and methods

Two trainees with no experience in PCNL attended the MTS under the supervision of an experienced mentor. The MTS included five modules, comprising an initial animal laboratory course (using pigs), to acquire basic skills (Module 1), and Modules 2–5 included making the puncture, tract dilatation, single-stone and large-stone management in clinical cases, respectively. Each participant progressed from one module to the next under constant mentoring and evaluation by the mentor. When the trainees completed the MTS they proceeded to perform 60 PCNL procedures independently while the mentor performed 25 for comparison purposes. A global rating scale was used for the objective evaluation of the trainees. Peri-operative variables were recorded and statistically compared as appropriate. Statistical significance was defined as P < 0.05.

Results

One pig and 16 patients, and two pigs and 22 patients, were necessary to complete the MTS by each subject. There were no significant differences among the characteristics of the independently performed operations. The duration of surgery and fluoroscopy achieved a plateau similar to those of the mentor after ≈ 30 patients. The decrease in haemoglobin level, stone-free and complication rates in the patients were similar among the two trainees and the mentor. The complication rate of the trainees and the mentor never exceeded 13.3%.

Conclusion

The MTS successfully combined animal and stepwise clinical training based on a standardised technique and objective evaluation.

Review on renal recovery after anatrophic nephrolithotomy: Are we really healing our patients?

The main goals for urinary stone treatment are to preserve renal function, reduce or avoid complications related to calculi, and to render the patient free of calculi as soon as possible. Anatrophic nephrolithotomy (ANL) is a valid and useful alternative for conventional staghorn calculi excision. Although excellent stone free rates can be achieved with ANL there are some drawbacks that may be of concern. Morbidity related to intraoperative and postoperative complications is one of them. Another, great concern is the possibility of reduction on renal function related to the procedure itself. This may be related to nephron injury during nephrotomy and parenchymal closure or to ischemic injury. In this review we assess functional results after anatrophic nephrolithotomy.

Retrograde upper-pole calyceal access for percutaneous nephrolithotripsy of stones in the lower-pole calyx

Objective

To present the results of upper calyceal access during percutaneous nephrolithotripsy (PCNL) for stones in the lower calyx, as PCNL is considered the most effective minimally invasive surgery for managing lower calyceal stones, with percutaneous access either directly to the lower calyx or through an upper or middle calyx.

Patients and methods

The study included 76 patients with single (51) and multiple (25) stones in the lower calyx, and stones in the lower calyx plus renal pelvis (six) and associated pelvi-ureteric junction obstruction (PUJO, five). They were managed by PCNL using retrograde access through the upper-pole calyx in addition to laser endopyelotomy for the PUJO.

Results

The mean duration required for establishing the retrograde nephrostomy tract was 14.4 min, and for completing the procedure was 40 min. The mean fluoroscopy exposure time was 3.2 min. Access from the upper calyx allowed easy and rapid advancement of the nephroscope to the lower calyx. The stones varied in size, at 10–25 mm. Stones were cleared completely in 70 of the 76 patients (92%); the stone-free rate was 100%. The residual stone fragments (2–4 mm) in the remaining six patients (8%) were considered insignificant. Complications were minor in four patients (5%), and included pleural effusion in two, bleeding in one and an arteriovenous fistula in one.

Conclusions

Upper-pole calyceal access for PCNL provides easy and effective clearance of stones in the lower calyx. This access should be considered for PCNL of single or multiple stones in the lower calyx.