Present indications and techniques of percutaneous nephrolithotomy: What the future holds?

Percutaneous nephrolithotomy for adult renal transplant de novo graft lithiasis: a single center analysis and systematic review of the literature

INTRODUCTION/OBJECTIVE

Graft stones in renal transplant recipients pose a unique challenge, finding effective interventions to ensure optimal graft function and patient well-being. Various methods of stone clearance have been described for graft stones, including percutaneous nephrolithotomy (PCNL). While PCNL is a promising approach for managing graft stones, specific outcomes and associated characteristics for this approach have not been comprehensively evaluated before. This study aims to evaluate the safety and efficacy of the use of PCNL as the primary intervention of graft stones by assessing stone-free rates (SFR), treatment impact on graft function, and perioperative complications.

METHODS

A retrospective clinical audit was performed for all transplants performed in a single center from 2007 to 2022, which included all graft lithiasis patients who were treated with PCNL. Both perioperative parameters and post-operative outcomes were collected. In addition, a systematic review including articles from MEDLINE, Embase, Web of Science yielded 18 full-text articles published between 1/1/2000 and 15/11/2023. The results pertaining to patients who underwent PCNLs for graft stones were cross-referenced and thoroughly evaluated. The review encompassed a comprehensive analysis of clinical data, postoperative outcomes, and procedural details. The protocol for the systematic review was prospectively registered on PROSPERO (CRD42023486825).

RESULTS

In our center, 6 graft lithiasis patients were treated with PCNL. The initial SFR was 83.3%. SFR at 3 months and 1 year were both 100.0%. SFR at 3 years was 66.7%. Other centers reported initial SFR of 82.6-100.0% (interquartile range). SFR at 3 months, 1 year, 3 years was not well reported across the included studies. Incidence of graft lithiasis ranged from 0.44%-2.41%. Most common presentations at diagnosis were oliguria/anuria/acute kidney injury and asymptomatic. Reported complications included blood loss, transient hematuria, high urine output, sepsis, and damage to surrounding structures. The most commonly reported metabolic abnormalities in transplant lithiasis patients included hyperuricemia and hyperparathyroidism.

CONCLUSION

PCNL is a practical and efficient choice for addressing graft lithiasis, demonstrating excellent stone clearance and minimal perioperative complications. These findings show the importance of PCNL as a primary intervention in this complex patient population.

Developing an Ex Vivo Pig Model for Teaching Ultrasound and Fluoroscopy-Guided Percutaneous Renal Access

Introduction: Establishing percutaneous renal access is the key initial step to percutaneous nephrolithotomy; however, learning the technique during surgery for trainees is complicated by the number of approaches used to gain access, limited completion time during a breath hold. and attempt to minimize the number of passes through a kidney. There are many training models for percutaneous access commercially available all with their respective limitations. Our objective was to develop a low-cost, high-fidelity percutaneous access training model that addresses existing limitations and can be used with both ultrasound and fluoroscopy guidance. Methods: After a formal ethics exemption was attained, pig cadavers were harvested for flank, kidneys, and ureters. These were incorporated into a composite porcine tissue mould, created within a gelatin matrix. In the initial assessment, establishing percutaneous access under both ultrasound and fluoroscopy guidance was tested to refine usability. Once acceptable, its use during a training course was evaluated to assess impressions for use with ultrasound. Results: We were able to create a $45USD biodegradable model, which can facilitate percutaneous access using: fluoroscopy with intrarenal contrast; fluoroscopy with endoscopic guidance; and fluoro-less that is, ultrasound only. A cohort of 12 Canadian Postgraduate Year-3 residents who used the model for ultrasound access agreed that the model simulated a comparable tactile experience (58.33%) and anatomy (75%) to humans. Furthermore, majority of the residents agreed that model was easy to use with ultrasound guidance (91.67%), was a beneficial experience for their learning and future practice (83.33%) and if available would use to complement their intraoperative training (83.33%). Conclusion: We were able to develop a low-cost, preliminarily tested ex vivo pig model for percutaneous access compatible with multiple imaging modalities. We will continue refining our model and seek to understand its benefits when teaching percutaneous access to varying levels of learners.

Comparative Analysis of Super-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for the Management of Renal Calculi ≤2 cm Among Somali Population

Background: Limited data have explored the efficacy of super-mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) in managing ≤2 cm renal calculi. This study aims to comprehensively evaluate the safety and effectiveness of SMP compared with RIRS. Methods: This prospective cohort study investigated 210 patients with renal calculi (≤2 cm) undergoing SMP or RIRS, randomly recruited over 4 years. In total, 51.4% underwent SMP and 48.6% underwent RIRS. Results: The mean patient age was 31.3 ± 14.7 years; 56.7% were men, mean stone size of 1.3 ± 0.28 cm, and stone hardness of 1190.1 ± 352.83 Hounsfield units. Pearson's correlation indicated negative correlations for SMP with hospital stays (r = -0.138, p = 0.046), operating time (r = -0.519, p < 0.001), and stone-free rate (SFR) (r = -0.161, p = 0.020); and a positive correlation with a postoperative ureteral catheter (r = +0.389, p < 0.001). With regard to RIRS, the study shows a positive correlation with hospital stay (r = +0.138, p = 0.046), operating time (r = +0.519, p < 0.001), and SFR (r = +0.161, p = 0.020); and a negative correlation with postoperative ureteral catheter (r = -0.389, p < 0.001). Logistic regression, using SMP as the reference, RIRS was associated with β = +0.31, and 1.20 (95% confidence interval [CI], 1.14-1.27, p ≤ 0.001) risk of operation duration and β = +0.37, 1.44 (95% CI, 1.00-2.07, p = 0.047) risk of longer hospital stay. Conclusion: This study investigates the suitability of SMP and RIRS for treating renal calculi ≤2 cm. SMP demonstrated superior efficacy with significantly shorter operating times and reduced hospital stays, suggesting potential advantages for managing lower volume renal stones.

The Analgesic Effects of the Thoracic Paravertebral Block on Post-percutaneous Nephrolithotripsy: A Retrospective Study

INTRODUCTION

Percutaneous nephrolithotripsy (PCNL) is a minimally invasive procedure for treating large and complex kidney stones, often resulting in significant post-operative pain and increased opioid use. This study aims to compare pain scores between patients undergoing PCNL who did and did not receive a preoperative single-shot thoracic paravertebral block (PVB) at the post-anesthesia care unit (PACU) as the primary outcome. Secondary outcomes were patient-controlled analgesia (PCA) usage on post-operative day 1 (POD 1), total opioid consumption on PACU and POD 1, and post-operative nausea and vomiting (PONV).

METHODS

A retrospective cohort study was conducted on the medical records of 341 patients who underwent PCNL from July 2014 to April 2016 in a single major academic center. PVB was administered at thoracic levels T7-9 using a volume of 20 cc of bupivacaine, ranging from 0.25% to 0.5%, to achieve the desired analgesic effect.

RESULTS

After excluding 34 patients, the study included 123 in the no block (NB) group and 149 in the regional anesthesia (RA) group. There were no differences in demographics, including age, sex, weight and height, BMI, and indication for PCNL. The results revealed that the RA group experienced a statistically significant reduction in PCA usage in both crude and adjusted models (adjusted logistic regression analysis: OR = 0.19, 95% CI = 0.05-0.60; p = 0.008). However, there were no significant changes in total opioid consumption, pain scores, or incidents of PONV.

CONCLUSION

The retrospective analysis did not reveal any discernible advantage in pain management associated with the use of PVB for post-PCNL analgesia, except for reducing the percentage of PCA narcotics used. Future investigations with larger sample sizes and meticulous control for surgical indications and complexity are imperative to accurately assess the efficacy of this block in the context of post-PCNL surgery.

Acute liver injury and contralateral pleural effusion as two rare complications following percutaneous nephrolithotomy: a case report

INTRODUCTION

Percutaneous Nephrolithotomy (PCNL) is a widely used surgical intervention for removing large and complex renal calculi. While considered a safe and effective procedure, it can still lead to severe and rare complications, including bleeding, pulmonary complications, and liver dysfunction.

CASE PRESENTATION

This case report presents a case who underwent PCNL for a kidney stone and subsequently developed a series of rare and severe complications. Following the PCNL procedure, the patient experienced significant bleeding, a known but uncommon complication of PCNL, pulmonary complications, a common complication that may carry a risk of death, and acute liver failure, an exceedingly rare consequence of PCNL.

CONCLUSION

In summary, while PCNL is a valuable technique for treating kidney stones, it is not without risk. This case underscores the importance of recognizing and managing rare complications following PCNL surgery, highlighting the need for vigilance, multidisciplinary care, and timely interventions to ensure favorable patient outcomes.

Tight junction and kidney stone disease

Defects of tight junction (TJ) are involved in many diseases related to epithelial cell functions, including kidney stone disease (KSD), which is a common disease affecting humans for over a thousand years. This review provides brief overviews of KSD and TJ, and summarizes the knowledge on crystal-induced defects of TJ in renal tubular epithelial cells (RTECs) in KSD. Calcium oxalate (CaOx) crystals, particularly COM, disrupt TJ via p38 MAPK and ROS/Akt/p38 MAPK signaling pathways, filamentous actin (F-actin) reorganization and α-tubulin relocalization. Stabilizing p38 MAPK signaling, reactive oxygen species (ROS) production, F-actin and α-tubulin by using SB239063, N-acetyl-L-cysteine (NAC), phalloidin and docetaxel, respectively, successfully prevent the COM-induced TJ disruption and malfunction. Additionally, genetic disorders of renal TJ, including mutations and single nucleotide polymorphisms (SNPs) of CLDN2, CLDN10b, CLDN14, CLDN16 and CLDN19, also affect KSD. Finally, the role of TJ as a potential target for KSD therapeutics and prevention is also discussed.

Predictive factors of delayed bleeding after percutaneous nephrolithotomy requiring angioembolization

Objectives

To investigate the predictive factors of delayed post-percutaneous nephrolithotomy (PCNL) haemorrhage because of arteriovenous fistula (AVF) or pseudoaneurysm (PA) and compare the factors between AVF and PA.

Patients and methods

This is a case-control study with a case-to-control ratio of 1:3. Out of 5077 patients who underwent PCNL from April 2015 to April 2018 in three different teaching hospitals, 113 had post-PCNL haemorrhages because of AVF and/or PA. Seventy-two patients met the inclusion criteria and entered the study as cases, while 216 patients without any postoperative complications were selected as controls.

Results

Of all 72 studied patients with complications after PCNL, 35 (48.6%) had AVF, and the rest had PA. The regression model revealed that a history of diabetes (odds ratio [OR]: 2.799, 95% confidence interval [CI]: 1.392-5.630, p-value = 0.004) and renal anomalies (OR: 2.929, 95% CI: 1.108-7.744, p-value = 0.03) were associated with developing delayed post-PCNL haemorrhage. However, no differences were seen between AVF and PA regarding selected variables (p-value > 0.05).

Conclusion

History of diabetes and renal anomalies were predictive factors for delayed post-PCNL haemorrhage, but no predictive factors were found to differentiate PA and AVF from one another.

Current advances in pain regimens for percutaneous nephrolithotomy A comprehensive review

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) causes pain and discomfort after surgery. The primary causes of immediate postoperative pain after PCNL are visceral pain from the ureters and kidneys, and body surface discomfort from incisions. Acute, untreated pain has the potential to develop into chronic pain, which remains a considerable burden for the rehabilitation of patients. The goal of this review was to describe the current options for treating pain post-PCNL.

METHODS

We conducted a literature review of all published manuscripts on pain protocols for patients undergoing PCNL and related topics; 50 published manuscripts were identified and reviewed.

RESULTS

PCNL morbidity must be reduced by an appropriate management of postoperative pain. Opioids, multimodal therapy, tubeless PCNL, reduced size of nephrostomy tube, and regional anesthesia are currently available for reducing postoperative pain.

CONCLUSIONS

Implementing successful treatment strategies for postoperative pain after PCNL is key in reducing the morbidity and mortality of PCNL.

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

Percutaneous Nephrolithotripsy in Morbidly Obese Patient: A Case Report

A 50-year old male patient with morbid obesity was admitted for removal of large staghorn calculi and multiple small stones in the left kidney. The patient was managed by Percutaneous Nephrolithotomy (PCNL). Surgery was carried out in prone position and Alken's metal dilators were used for tract dilation. Alken dilators were inserted without any challenges, and the procedure was completed in a shorter span of time than anticipated with total operative time of 2 hours, including the change of positioning from lithotomy to prone. No intra-operative or post-operative complications were encountered. The patient has been followed up for 6 months post-operatively, without any complications or any evidence of stone recurrence.

Open surgery versus percutaneous nephrolithotomy for management of staghorn calculi

BACKGROUND

For urologists, treating staghorn stones remains a difficult challenge. Various studies have evaluated the results of percutaneous nephrolithotomy (PCNL) and open surgery in different populations but these results were controversial. Here, we aimed to compare and evaluate the results of open surgery and PCNL in the treatment of staghorn stones.

METHODS

This retrospective descriptive study was performed to compare the results of open surgery and PCNL in the treatment of staghorn stones in 2013-2021. A total of 360 participants were studied among the population. Demographic data of patients including age, gender, and comorbidities were obtained. We assessed variables including type of stone, serum creatinine, degree of hydronephrosis, and urine culture before the operation. All participants in our study were informed of the two surgical alternatives.

RESULTS

The mean length of hospital stay in PCNL patients was 3.88 ± 1.76 and in open surgery patients was 5.858 ± 2.12 (P = 0.003). In 30 patients (13.9%) in the PCNL group and 27 patients (18.8%) in the open surgery group, bleeding necessitating blood transfusion was the only intraoperative complication. 309 patients (85%) had no residual stones at the time of discharge from the hospital, which was 81.9% (177 cases) in patients treated with PCNL and 91.6% (132 patients) in the open surgery group (P > 0.05).

CONCLUSION

Staghorn calculi can be managed effectively with open surgery or PCNL. Given the reduced postoperative complication rate and higher stone-free rate, we believe open surgery is better technique for complicated staghorn stones with a high burden.

The Surgical Technique of Mini Percutaneous Nephrolithotomy

The mini percutaneous nephrolithotomy (mini-PCNL) has become a versatile tool to remove kidney stones >2 cm, lower pole stones >1 cm, renal stones previously unresponsive to shockwave therapy or inaccessible by ureteroscopy (within a caliceal diverticulum), stones within complex urinary tracts (urinary diversions, transplanted kidney, and horseshoe kidneys), and large impacted proximal ureteral stones. After positioning in either the supine or prone position, a cystoscopy is performed to place an open-ended catheter, occlusion balloon, or Accordian device into the collecting system. A foley catheter is placed in the bladder. An ultrasound with a curvilinear probe is used to survey the kidney and guide access into the collecting system with an 18 g percutaneous needle. Once access is obtained, a small 0.5 cm skin incision is made and the percutaneous tract is dilated over a wire. A 16.5F metallic or self-dilating suctioning access sheath is positioned with fluoroscopic guidance. A 12F rigid mini-PCNL nephroscope is used to evaluate the collecting system. Once a calculus is observed, options for stone fragmentation include a lithotripter with ultrasonic and ballistic energy, or laser lithotripsy using holmium or thulium laser fibers. Flexible ureteroscopy can be considered to ensure clearance of the collecting system. A 6F ureteral stent can be placed in either a retrograde or antegrade approach for drainage. The tract is sealed using Surgiflo hemostatic matrix with thrombin. Guidelines for postoperative care and troubleshooting techniques for mini-PCNL are reviewed along with the surgical steps in the accompanying video (Supplementary Video S1). There are few randomized trials comparing mini-PCNL with standard PCNL and ureteroscopy. There is some evidence to suggest a difference in transfusion rates comparing mini- and standard PCNL, as well as differences in stone-free rates when comparing mini-PCNL with ureteroscopy for the treatment of lower pole stones.

Pre-operative Percutaneous Nephrolithotripsy Characterisation of Kidney Stones with Second-Generation Dual-Source Dual-Energy Computed Tomography

Background: The current clinical practice to manage kidney stone requires knowledge of the stone composition. However, it is often difficult to determine the actual stone composition before a stone is operatively removed from the patient. Dual-energy computed tomography (DECT) can predict urinary stone composition, but it is not widely adopted. The purpose of the study was to investigate the use of a second-generation DECT with tin or stannum (Sn) filter for characterising the kidney stones composition. Methods: Thirty-three kidney stones were scanned ex vivo using a dual-source (DS)DECT scanner with dual-energy (DE) mode of 80/140 kVp with and without 4 mm Sn filtration. DE ratio was calculated to determine the kidney stones composition (uric acid, calcium oxalate, calcium phosphate and cystine). The median DE ratio of the stones was compared using Wilcoxon signed rank test and the results were further correlated with semi-quantitative Fourier transform infrared (FTIR) spectroscopy analysis using Kendall’s Tau test with P < 0.05 deemed to be statistically significant. Results: Second-generation DS-DECT could significantly discriminate the stones composition with and without Sn filtration (P < 0.001). The median DE ratio of uric acid, calcium oxalate and cystine stones were significantly higher with Sn filtration than those without filtration (P < 0.05). DECT results revealed significant correlation with FTIR spectroscopy analysis (r = 0.716, P < 0.001). DECT with Sn filtration showed increased performance (100% sensitivity, 0% specificity) than those without filtration (48.5% sensitivity, 0% specificity) in the detection of the kidney stone subtypes. Conclusion: In the second-generation DECT with additional Sn filtration, DECT has shown a significant performance in characterising and discriminating the kidney stone composition. This may improve diagnostic and therapy management in kidney stones cases.

Extracorporeal shock-wave lithotripsy: is it still valid in the era of robotic endourology? Can it be more efficient?

PURPOSE OF REVIEW

The aim of the article is to evaluate the actual role of extracorporeal shock-wave lithotripsy (ESWL) in the management of urolithiasis based on the new developments of flexible ureterorenoscopy (FURS) and percutaneous nephrolithotomy (PCNL).

RECENT FINDINGS

In Western Europe, there is a significant change of techniques used for treatment of renal stones with an increase of FURS and a decrease of ESWL. The reasons for this include the change of indications, technical improvement of the endourologic armamentarium, including robotic assistance. Mostly relevant is the introduction of digital reusable and single-use flexible ureterorenoscopes, whereas micro-PCNL has been abandoned. Some companies have stopped production of lithotripters and novel ideas to improve the efficacy of shock waves have not been implemented in the actual systems. Promising shock-wave technologies include the use of burst-shock-wave lithotripsy (SWL) or high-frequent ESWL. The main advantage would be the very fast pulverization of the stone as shown in in-vitro models.

SUMMARY

The role of ESWL in the management of urolithiasis is decreasing, whereas FURS is constantly progressing. Quality and safety of intracorporeal shock-wave lithotripsy using holmium:YAG-laser under endoscopic control clearly outweighs the advantages of noninvasive ESWL. To regain ground, new technologies like burst-SWL or high-frequent ESWL have to be implemented in new systems.

A Novel Embolization Technique for Renal Hemorrhage Complication by Autologous Fat Tissue

The percutaneous nephrolithotomy method is the most used treatment option for urinary stone disease. Bleeding is the most feared complication of this method. Transcatheter coil or medical glue embolization is currently the used treatment option for this bleeding complication. The aim of this report to show the novel subcutaneous fat tissue embolization technique for percutaneous nephrolithotomy related bleeding complications. In these two cases, we treated the percutaneous nephrolithotomy related bleeding complication with subcutaneous fat tissue. Subcutaneous fat tissue was taken with subcutaneous fascia from the femoral site by 1 cm incision. This tissue to be used for embolization was passed on the 0.014 guidewire from the back end of this guidewire (like shish kebab). The fat tissue passed on the 0.014 wire was sent to the bleeding site through the guiding catheter and guideliner, over the 0.014 guidewire with the monorail balloon (as a pusher) placed behind this fat tissue. The subcutaneous fat tissue with subcutaneous fascia embolization was completely stopped the bleeding and fistula. We have successfully used a novel embolization technique for fat tissue embolization to the bleeding site (Ari technique). Subcutaneous fat tissue embolization with the novel embolization technique for percutaneous nephrolithotomy related bleeding is a safe and reliable treatment option.

Percutaneous Nephrolithotomy in the 80 Years of Age and Older Population

OBJECTIVE

To evaluate feasibility of percutaneous nephrolithotomy (PCNL) for complex nephrolithiasis in patients 80 years of age and older compared to younger individuals.

METHODS

From an institutional IRB-approved database, 1,647 patients were identified who underwent PCNL from 1999 to 2019. Patients were stratified by age: group 1 (20-59), group 2 (60-79), and group 3 (>80). Statistics were performed using chi-square and ANOVA to compare outcomes.

RESULTS

Of the 1,647 patients, median age was 46, 66, and 83, respectively (P <0.0001). Three patients within group 3 were 90 or older. Females made up 54%, 46%, 56% of patients (P = 0.02). Average stone size with SD was 2.6 ± 2.2, 2.5 ± 2.3, 2.2± 1.9 cm for each group (P = 0.06). Mean preoperative hemoglobin (Hgb) was significantly lower in the 80+ group (13.8, 13.4, 13.1 g/dL, P <.0001). Change in Hgb was not significantly different. There were more Clavien II-IV complications (10.4, 14.4, 28.8%; P = 0.02) and transfusions (2.3, 4.7, 10.2%; P <0.001) in the elderly. The most common complications in the 80+ group were bleeding related (10.1%). No difference in readmission rates or ICU admissions was noted.

CONCLUSION

PCNL is feasible in the extremely elderly; however with a higher rate of complications and longer hospitalizations. No long-term sequelae or deaths in the 80 and older cohort were seen. This study allows us to appropriately counsel older patients on a realistic postoperative course and supports use of PCNL as the best means of long-term survival.