Complications of percutaneous nephrolithotomy: classification, management, and prevention

The modified 5-item frailty index as a predictor of perioperative risk in patients undergoing percutaneous nephrolithotomy

INTRODUCTION

The modified 5-item frailty index is a relatively new tool to assess the post-operative complication risks. In urology, there is limited literature on the impact of frailty on percutaneous nephrolithotomy (PCNL) outcomes. We aimed to compare the predictive value of the modified 5-item frailty index (mFI-5) to identify high risk patients prior to PCNL.

METHODS

A database of patients undergoing PCNL, between 2015 and 2022, was analyzed. Patient frailty was assessed using the mFI-5 index. The mFI-5 index was calculated based on the presence of the five co-morbidities: congestive heart failure within 30 days prior to surgery, diabetes mellitus, chronic obstructive pulmonary disease, partially dependent or totally dependent functional health status at time of surgery, and hypertension requiring medication. Patients were grouped as not frail (mFI-5 = 0), intermediate (mFI-5 = 1), and severely frail (mFI-5 ≥ 2). Primary outcomes were 30-day postoperative complications. Secondary outcomes were hospitalization: total hospital length of stay, reoperation, and unplanned readmission.

RESULTS

From a total of 320 PCNL patients included for analysis, 54.06% (n = 173) were not frail, 17.81% (n = 57) were intermediate, and 28.12% (n = 90) were severely frail. Frail patients were likely to be older (p = 0.002) and have a higher American Society of Anesthesiologists score (p = 0.001), chronic kidney disease (p < 0.001). Patients of intermediate or severe frailty were more likely to exhibit postoperative sepsis (p = 0.042), significant blood loss (p = 0.036) and require intensive care units admissions (p = 0.0015). Frail patients had a longer hospital length of stay (p < 0.001) and tended to require reoperation (p = 0.001), and unplanned readmission (p = 0.02).

CONCLUSION

Frailty assessment appears useful in stratifying those at risk of extended hospitalization, septic and hemorrhagic complications, readmission, or reoperation after PCNL. Preoperative assessment of frailty phenotype may give insight into treatment decisions and assist surgeons in counselling patients on expected course and hospital stay following PCNL.

Recent advances in the treatment of renal stones using flexible ureteroscopys

Upper urinary tract stones are a common urological disease that can be treated by flexible ureteroscopy (FURS) through the natural urinary tract, in addition to extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy. The advantages of FURS are less trauma, faster recovery, and fewer complications, while its disadvantages include poor results of lithotripsy and stone extraction when dealing with larger stones, and prolonged operation time. Over the last two decades, the emergence of new technologies such as FURS combined with negative pressure suction, robot-assisted FURS, and artificially intelligent FURS, coupled with improvements in laser technology (the use of thulium fiber lasers and the invention of single-use flexible ureteroscopes (su-fURS) suitable for primary level application, have significantly increased the global adoption of FURS. This surge in usage holds a promising future in clinical application, benefiting a growing number of patients with renal calculi. Accompanied by changes in technical concepts and therapeutic modalities, the scope of indications for FURS is broadening, positioning it as a potential primary choice for urolithiasis treatment in the future. This review outlines the progress in employing FURS for the treatment of renal calculi in order to generate insights for further research.

Is the Mayo Adhesive Probability Score Predictive in Patients Undergoing Percutaneous Nephrolithotomy?

Introduction: Mayo Adhesive Probability (MAP) score was developed as a means to predict the presence of adherent perinephric fat. Our aim was to determine the predictive value of the MAP score on surgical outcomes in patients undergoing standard adult percutaneous nephrolithotomy (PCNL). Materials and Methods: We retrospectively analyzed the data from 130 renal units that underwent PCNL between January 2022 and 2023. MAP scores 0-2 were classified as low, whereas MAP scores 3-5 were classified as high. The impact of the MAP score on perioperative and postoperative outcomes was studied. All statistical analyses were performed using SPSS 24.0 for Windows. Results: The median age of the patients at the time of surgery was 48 (21) years, with a female-to-male ratio of 1:1.82. The median MAP score was 2 (2), with 43.8% of patients falling into the high MAP score group. Advanced age, hypertension history, low estimated glomerular filtration rate (eGFR) levels, and low renal parenchymal thickness were significantly higher in the high MAP score group (P = .010, P = .004, P = .001, and P = .005, respectively). Female patients had a significantly higher MAP score of 0 (P = .021). Operation time, postoperative hematocrit decrease, blood transfusion rate, postoperative fever rate, hospitalization, and stone-free rates were comparable between the low and high MAP score groups (P = .535, P = .209, P = .313, P = .289, P = .281, and P = .264, respectively). Gender and eGFR levels were shown to be significant predictors of a MAP ≥3 (P = .004 and P = .003, respectively). Conclusion: The present study showed that the MAP score groups had similar perioperative and postoperative results. Low eGFR levels and the male gender were associated with MAP score ≥3. To determine the predictive MAP score value for PCNL outcomes, more prospective studies are needed.

Percutaneous antegrade management of large proximal ureteral stones using non-papillary puncture

Objective

To evaluate the feasibility and the safety of medial non-papillary percutaneous nephrolithotomy (npPCNL) for the management of large proximal ureteral stones.

Methods

We evaluated prospectively collected data of 37 patients with large proximal ureteral stones more than 1.5 cm in diameter treated by prone npPCNL. Depending on stone size, in-toto stone removal or lithotripsy using the Lithoclast® Trilogy (EMS Medical, Nyon, Switzerland) was performed. Perioperative parameters including operative time (from start of puncture to the skin suturing), stone extraction time (from the first insertion of the nephroscope to the extraction of all stone fragments), and the stone-free rate were evaluated.

Results

Twenty-one males and 16 females underwent npPCNL for the management of large upper ureteral calculi. The median age and stone size of treated patients were 58 (interquartile range [IQR]: 51-69) years and 19.3 (IQR: 18.0-22.0) mm, respectively. The median operative time and stone extraction time were 25 (IQR: 21-29) min and 8 (IQR: 7-10) min, respectively. One case (2.7%) of postoperative bleeding and two cases (5.4%) of prolonged fever were managed conservatively. The stone-free rate at a 1-month follow-up was 94.6%.

Conclusion

The npPCNL provides a straight route to the ureteropelvic junction and proximal ureter. Approaching from a dilated portion of the ureter under low irrigation pressure with larger diameter instruments results in effective and safe stone extraction within a few minutes.

Assessing the Variability of the Twelfth Rib as a Landmark for Percutaneous Nephrolithotomy Using Computed Tomography

BACKGROUND

The variability in length of the twelfth rib is mentioned in the literature but has never been formally studied. The highly variable rib length provides a challenge for urologists seeking a consistent landmark for Percutaneous Nephrolithotomy (PCNL). We set out to determine whether the twelfth rib is safe to use as a consistent landmark for surgery.

METHODS

Single centre, cross-sectional retrospective observational study and analysis of CT scans of 100 adults who had imaging between 23rd March and 12th April 2020. The distance from the mid-sagittal line to the twelfth rib tip in the axial plane was measured as was the distance from the twelfth rib tip to the kidney, spleen and liver.

RESULTS

Length from the mid-sagittal line to the right twelfth rib tip varied from 46 (percentile 95% CI 40 to 57) to 136mm (percentile 95% CI 133 to 138). On the left, the distances varied from 55 (percentile 95% CI 50 to 64) to 134mm (percentile 95% CI 131 to 135). Twenty-three percent of people had an organ lying between the tip of the twelfth rib and the kidney on the right and 11% on the left.

CONCLUSION

The twelfth rib is highly variable in length. Similar variability was recorded in the distance from the tip to intra-abdominal organs. Due to the frequency of organs lying between the tip of the rib and the kidney it should not be used as a landmark for accessing the kidney without prior knowledge of an individual patient's anatomy as seen on imaging.

[New treatment concepts for colonic injury after percutaneous nephrolithotomy]

Percutaneous nephrolithotomy (PCNL) has become the gold standard for the treatment of large kidney stones > 2 cm and stones in the lower calyces > 1.5 cm. Despite the miniaturization of instruments and the greater expertise of urologists, serious complications can still occur. One of the most dangerous complications is intestinal perforation. Current database analyses report colonic injury in 0.3-0.8% of all cases. These injuries can be treated with either conservative management with long-term drainage and parenteral nutrition, or an exploratory laparotomy with primary closure or creation of a colostomy becomes necessary. We present the case of a 53-year-old woman who underwent left-sided PCNL for a single kidney stone. After removal of the nephrostomy, feces leaked from the puncture channel. After literature research and an interdisciplinary case presentation, the decision was made in favor of an undescribed therapy concept for colon injury after PCNL. After taking laxatives, a colonoscopy was performed. The entry and exit points of the puncture were identified and were both treated with an OTSC® clip (InMedi, Langenhagen, Germany). Immediately after the intervention stool leakage via the puncture channel stopped and the patient was allowed to eat normally. A control sonography on the third day revealed minimal fluid retention in the retroperitoneum which did not require treatment. The patient was then discharged symptom-free.

European Association of Urology Section of Urolithiasis and International Alliance of Urolithiasis Joint Consensus on Retrograde Intrarenal Surgery for the Management of Renal Stones

BACKGROUND

Retrograde intrarenal surgery (RIRS) has become the preferred treatment modality for nephrolithiasis. However, because of ongoing uncertainties regarding the optimal perioperative management, operative technique, and postoperative follow-up, as well as a lack of standardization for outcome reporting, consensus is needed to achieve more uniform clinical practice worldwide.

OBJECTIVE

To develop recommendations for RIRS on the basis of existing data and expert consensus.

DESIGN, SETTING, AND PARTICIPANTS

A protocol-driven, three-phase study was conducted by the European Association of Urology Section of Urolithiasis (EULIS) and the International Alliance of Urolithiasis (IAU). The process included: (1) a nonsystematic review of the literature to define domains for discussion; (2) a two-round modified Delphi survey involving experts in this field; and (3) an additional group meeting and third-round survey involving 64 senior representative members to formulate the final conclusions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The results from each previous round were returned to the participants for re-evaluation of their decisions during the next round. The agreement threshold was set at 70%.

RESULTS AND LIMITATIONS

The panel included 209 participants who developed 29 consensus statements on the following topics of interest: (1) perioperative infection management; (2) perioperative antithrombotic therapy; (3) fundamentals of the operative technique; and (4) standardized outcome reporting. Although this consensus can be considered as a useful reference for more clinically oriented daily practice, we also acknowledge that a higher level of evidence from further clinical trials is needed.

CONCLUSIONS

The consensus statements aim to guide and standardize clinical practice and research on RIRS and to recommend standardized outcome reporting.

PATIENT SUMMARY

An international consensus on the best practice for minimally invasive surgery for kidney stones was organized and developed by two international societies. It is anticipated that this consensus will provide further guidance to urologists and may help to improve clinical outcomes for patients.

Percutaneous Nephrostomy in Complicated Urinary Tract Infections

Background

The study aimed to determine the various indications for percutaneous nephrostomy (PCN) primarily in patients with a urinary tract infection and to determine the various complications arising in these patients due to the procedure.

Materials and methods

A retrospective study of five-year data based on registers of the Department of Urology was performed. Among 716 patients, 226 inpatient data were obtained, curated, and analyzed. Indications for PCN, the periprocedural complications, the PCN's duration, details of antibiotics, risk factors for UTI, development of acute kidney injury, and renal replacement therapy were recorded.

Results

Patients were mostly female (53.1%, n=120/226). Malignancy (n=109, carcinoma cervix=68/109) and nephrolithiasis (n=70) contributed to 79.2%. Infections such as pyelonephritis, renal abscess, perinephric abscess, and genitourinary tuberculosis were identified in 47. Infectious diseases were significantly associated with younger age, female gender, diabetes, and prior pyelonephritis. PCN was placed at a median of two days after admission, and bilateral PCN was placed in 36 (15.2%) patients. Hydroureteronephrosis (probably infected) was an indication for PCN in 164/226 patients. In 33 patients with an infectious disease, PCN was performed for an obstructed urinary system. One major and two minor complications gave a rate of 0.06% for patients with infections, which was less than the accepted threshold of 4%.

Conclusions

We intended to study the utility and problems with placing a PCN catheter in patients with complicated urinary infections. We conclude that PCN is a safe and effective procedure in urinary tract infections with obstructed drainage.

Comparison of pre-indwelling double-J stents versus ureteral catheters for artificial hydronephrosis in percutaneous nephrolithotomy: A retrospective cohort study

PURPOSE

To compare the clinical efficacy and safety of pre-indwelling double-J stents versus ureteral catheters for artificial hydronephrosis in percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

We retrospectively analyzed the data of 1,258 patients who underwent PCNL for kidney stones from August 2017 to July 2020 in our hospital. Among them, 682 patients had double-J stents inserted (DJ group) and 576 patients had ureteral catheters (UC group). We analyzed baseline patient characteristics, perioperative outcomes, and complications in both groups.

RESULTS

The puncture success rate was 97.9% and 97.4% in the DJ and UC groups, respectively (p>0.05). The operation time was 74.5±37.8 minutes in the DJ group compared with 80.8±38.5 minutes in the UC group (p=0.004). The total stone-free rate in the DJ and UC groups was 80.5% and 78.7%, respectively (p>0.05). The incidence of perioperative complications was relatively low in both groups and showed no obvious differences. In the subgroup analysis, the operation time for patients with no obvious or mild hydronephrosis preoperatively was significantly shorter in the DJ group than in the UC group (p<0.05). However, there were no significant differences among patients who had moderate or severe hydronephrosis preoperatively.

CONCLUSIONS

It is feasible, safe, and effective to create artificial hydronephrosis by insertion of pre-indwelling double-J stents in PCNL surgery. Furthermore, the operation time was significantly shorter in the DJ group than in the group with pre-indwelling ureteral catheters, especially in patients who had no obvious or mild hydronephrosis preoperatively.

Electromagnetic-guided puncture: a tool or a tale?

PURPOSE OF REVIEW

The puncture technique and site of the puncture can impact the clinical outcome and the development of postoperative adverse events following percutaneous nephrolithotomy (PCNL). The aim of the current review was to discuss the available puncture guidance approaches and outline the potential role of the recently introduced electromagnetic-guided method.

RECENT FINDINGS

The puncture and PCNL tract establishment is usually performed using fluoroscopic or ultrasound guidance or a combination of two approaches. Electromagnetic-guided puncture is one of the most recent advancements of technology. The puncture navigation to the renal collecting system is available after placing a special wire with an electromagnetic tracking sensor into the desired calyx through the flexible ureterorenoscope. The available experimental and clinical studies have shown a high first puncture rate, decreased median time for obtaining a puncture, and shorter learning curves for beginners.

SUMMARY

Fluoroscopic and ultrasound guidance are the main approaches used by urologists. However, these modalities require a steep learning curve, approximately 60 cases for reaching competency. The initial data on electromagnetic navigation have shown the feasibility and potential promising outcomes of this novel approach. New studies are required to investigate its potential implementation opportunities in the daily practice of urologists.

Worldwide practice patterns of percutaneous nephrolithotomy

PURPOSE

To evaluate the current practice of percutaneous nephrolithotomy (PCNL), conducting a worldwide survey among urologists with a special interest in endo-urology.

METHODS

A 22-question survey was specifically developed by the European Association of Urology (EAU) young academic urologists (YAU) and uro-technology (ESUT) groups and globally distributed via SurveyMonkey to almost 2000 members of Endourology Society. The questionnaire included questions dedicated to the demographics and general practice of the participating urologists.

RESULTS

In total, 441 responses (male/female ratio - 418/23) were received. A comparatively higher percentage of specialists (56.2%) practiced in academic institutions and had specific endo-urological fellowship training (56.7%). The classical prone PCNL remained the most practiced approach among the surveyed specialists, 47.7% stated to always do prone PCNLs, while 51.8% of respondents used multiple positioning options as required. The PCNL tract was mostly performed by urologists (84.3%) and fluoroscopic guidance was still predominantly used by 74.5% of respondents. The most practiced tract dilation method was balloon dilator used by 42% of respondents. Most of the surveyed urologists had ultrasonic, pneumatic or laser lithotripsy devices in their armamentarium. The use of some form of post-procedural drainage was reported in 85.1% of respondents, whereas tubeless PCNL remained a fairly uncommon practice.

CONCLUSION

The majority of urologists still use prone positioning, get their own access under fluoroscopy guidance and use a balloon for tract dilation. However, we also identified that when necessary, urologists will deviate from routine practice and change strategy, adopting other approaches for PCNL.

The comprehensive complication index as a tool for reporting the burden of complications after mini-percutaneous nephrolithotomy: is it time to leave the Clavien–Dindo classification behind?

Purpose

To validate the comprehensive complication index (CCI) for mini-percutaneous nephrolithotomy (mPCNL).

Methods

Data from 287 patients who underwent mPCNL were analyzed. Complications after mPCNL were classified using both the CCI and the Clavien–Dindo classification (CDC). Descriptive statistics and linear/logistic regression analyses detailed the association between clinical predictors and mPCNL outcomes.

Results

After mPCNL, 83 (28.9%) patients had complications, of which 12 (4.2%) patients with multiple complications had a higher CCI score compared to the traditional CDC system accounting only for the highest grade. The CCI enabled a more accurate prediction of length of stay (LOS) than CDC (CCI: r = 0.32; p < 0.01 vs. CDC: r = 0.26; p = 0.01). Patients with multiple complications had higher stone volume (p = 0.02), longer operative time and LOS (all p < 0.01). A higher rate of post-operative hospital readmission (33.3% vs. 9.9%, p = 0.02) and lower rate of stone free (33.3% vs. 64.7%, p = 0.04) were found in patients with multiple complications than in those with single complication. Linear regression analysis revealed that multiple complications were associated with longer LOS (p < 0.001) after accounting for BMI and stone volume. Similarly, having multiple complications was associated with fivefold higher risk of readmission (p = 0.02).

Conclusion

The CCI is a valuable metric for assessing post-operative complications after mPCNL. The cumulative CCI is a better predictor of LOS than the CDC for mPCNL. Minor complications not captured by the highest CDC score are relevant since patients with multiple complications have longer LOS and higher rate of readmission than those with single ones.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-04045-9.

Endoscopic Combined Intrarenal Surgery Versus Percutaneous Nephrolithotomy for Complex Renal Stones: A Systematic Review and Meta-Analysis

Background: Endoscopic combined intrarenal surgery (ECIRS) adds ureteroscopic vision to percutaneous nephrolithotomy (PCNL), which can be helpful when dealing with complex renal stones. Yet, there is still no consensus on the superiority of ECIRS. We aimed to critically analyze the available evidence of studies comparing efficacy, safety, bleeding risk, and efficiency of ECIRS and PCNL. Methods: We searched for studies comparing efficacy (initial and final stone-free rate), safety (postoperative fever, overall and severe complications), efficiency (operative time and hospital stay) and bleeding risk between ECIRS and PCNL. Meta-analysis was performed. Results: Seven studies (919 patients) were identified. ECIRS provided a significantly higher initial stone-free rate, higher final stone-free rate, lower overall complications, lower severe complications, and lower rate of requiring blood transfusion. There was no difference between the two groups in terms of postoperative fever, hemoglobin drop, operative time, and hospital stay. In the subgroup analysis, both minimally invasive and conventional ECIRS were associated with a higher stone-free rate and lower complication outcomes. Conclusions: When treating complex renal stones, ECIRS has a better stone-free rate, fewer complications, and requires fewer blood transfusions compared with PCNL. Subgroups either with minimally invasive or conventional intervention showed a consistent trend.

The use of ureteral access sheath during mini-percutaneous nephrolithotomy with high-power holmium YAG laser

PURPOSE

To present our preliminary results and describe a technical modification of mini-PCNL (12Fr) with the insertion of a ureteral access sheath (UAS) to facilitate the procedure.

METHODS

A prospective study for the time period of January 2020 to January 2021 was conducted including patients with renal stones sized ≤ 25 mm in whom prone mini-PCNL (tract size 12Fr) together with the retrograde insertion of UAS was performed. All patients had been prestented at least 1 week prior to the planned surgery. A single-step tract dilation to 12Fr diameter was performed through a nonpapillary medial puncture. The lithotripsy was achieved using high-power holmium yttrium aluminum garnet laser (Ho:YAG) with the 60 W power setting (40 Hz and 1.5 J). The follow-up investigations were planned at 1-month after the surgery.

RESULTS

In total, 32 patients with the median age and stone size of 56.5 (IQR = 53-62) years and 20.8 (IQR = 19.3-22.7) mm were included. The median operative and cumulative fluoroscopy time were 34.0 (IQR = 29.9-37.5) and 1.9 (1.8-2.1) min, respectively. The stone-free rate (SFR) at 1-month follow-up was 93.8% (30/32). Only one patient developed a fever and required prolonged antibiotic administration. None of the patients experienced clinically significant bleeding.

CONCLUSION

Our preliminary results showed that the use of UASs during mini-PCNL procedures is feasible and provides directed evacuation of the stone fragments reaching 93.8% SFR at a 1-month follow-up. Future well-designed studies are necessary to prove our findings.

Mini percutaneous nephrolithotomy versus standard percutaneous nephrolithotomy for the management of renal stones over 2 cm: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Standard percutaneous nephrolithotomy (sPCNL) is recommended for renal stones over 2cm. Mini percutaneous nephrolithotomy (mPCNL) has also emerged as a promising technique in this setting. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the safety and efficacy of sPCNL to mPCNL for the management of renal stones over 2cm.

EVIDENCE ACQUISITION

We systematically searched PubMed, Cochrane Library and Scopus databases until April 2021 and sources of grey literature for relevant RCTs. We performed a meta-analysis of odds ratios (ORs) to compare bleeding or other complications and stone-free rate (SFR) between sPCNL and mPCNL. Similarly, we undertook a metaanalysis of weighted mean differences for the mean operative and hospitalization time between the two techniques (PROSPERO: CRD42021241860).

EVIDENCE SYNTHESIS

Pooled data from 8 RCTs (2535 patients) were available for analysis. sPCNL was associated with a higher hemoglobin drop (0.59g/dl, 95%CI: 0.4-0.77, I2=93%), higher likelihood of postoperative blood transfusion (OR: 2.58, 95%CI: 1.03-6.45, I2=30%) and longer hospital stay (0.75 days, 95%CI: 0.45-1.05, I2=73%) compared to mPCNL. No significant differences were demonstrated in SFR (OR: 0.92, 95%CI: 0.74-1.16, I2=0%) and mean operative time (4.05 minutes, 95%CI: -9.45-1.37, I2=91%) after sPCNL versus mPCNL. Similarly, no significant differences were observed for postoperative fever, pain and Clavien-Dindo complications.

CONCLUSIONS

mPCNL represents a safe and effective technique and may be also recommended as a first-line treatment modality for well-selected patients with renal stones over 2cm. Still, further high-quality RCTs on the field are mandatory, since the overall level of evidence is low.

Can Color Doppler Ultrasound Challenge the Paradigm in Percutaneous Nephrolithotomy?

OBJECTIVES

Compare color Doppler (Color) ultrasound-guided puncture to common type-B (Type-B) ultrasound-guided puncture in reducing the incidence of hemorrhagic complications of percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A total of 348 patients who received PCNL from September 2017 to December 2018 were divided into Color (231 cases) and Type-B groups (117 cases). The avascular area of the target fornix was pinpointed in the Color group while the middle of the target fornix was the default puncture point in the Type-B group. Tract bleeding, nephrostomy tract creation time, operation time, postoperative hemoglobin (Hb) values and serum creatinine (Scr) concentrations, and stone-free rates were analyzed.

RESULTS

Color Doppler imaging revealed that 35.1% of the cases in the Color group (81/231) had variable artery positioning in the target fornix. Tract bleeding and postoperative Hb reduction in the Color group were significantly lower than the Type-B group (10.8% vs 24.8%, P=0.0007, and 4.87±8.58 vs 7.70±8.90 g/L, P=0.0044, respectively). The postoperative hospitalization of the Color group was also shortened (8.3±5.9 vs 9.7±3.0 d, P<0.0001). Although working channel creation took longer in this group (4.2±0.3 vs 3.6±0.2 min, P<0.0001), there were no significant differences in the total operation time between the two groups (39.2±15.2 vs 36.4±16.5 min, P=0.1097) or postoperative Scr and stone-free rates.

CONCLUSION

Vascular variation of the fornix is very common. Consistent puncture of the avascular area of the target fornix significantly lowered tract bleeding and postoperative Hb decrease compared to traditional procedures. Color Doppler ultrasound-guided puncture is thus useful to reduce the incidence of severe hemorrhagic complications of PCNL.

Outcome of Mini-Percutaneous Nephrolithotomy in Patients Under the Age of 18: An Experience With 112 Cases

Purpose: Renal calculi are becoming more common among children. Although, extracorporeal shock wave lithotripsy (ESWL) is the first choice in this age group, minimal invasive surgeries, such as percutaneous nephrolithotomy (PCNL), are indicated for some patients. Recently, PCNL devices have become smaller in size with acceptable efficacy and lower complications. We evaluated the outcomes and complications of mini-PCNL (MPCNL) surgery in our referral training centers.

Materials and Methods: Between September 2012 and January 2020, a total of 112 children under the age of 18, who had shown failure of ESWL, and/or their parents refused to do it, underwent MPCNL (15 Fr). The patients' profiles were reviewed for data collection including preoperative and stone data, operation information, and postoperative complications.

Results: Of 112 patients, 69 were boys, and 43 were girls. Their mean age was 8.6 years (14 months to 18 years). Mean stone size was 20 mm (14–34 mm). Seventy-four cases had renal pelvic stone, 22 had pelvis and lower pole, and 16 had staghorn. The mean operation time was 65 min (35–100 min), and mean radiation time was 0.6 min (0.2–1.4 min). Low-grade fever was detected in 14 patients (12.5%). Four patients needed blood transfusion and two had increased creatinine, which improved with conservative management. One patient developed urosepsis that resolved with antibiotic therapy. None of the patients had kidney perforation or other organ injury or death. Early stone-free rate (SFR) after operation was 90.2% (101 patients). Six patients had residual fragment <5 mm, which passed spontaneously in 2 weeks after operation (total SFR 95.3%). Three patients underwent second-look nephroscopy, and ureteroscopy was done for two patients due to migrated stone fragments to the distal ureter.

Conclusion: MPCNL is recommended as a safe alternative option for treatment of the nephrolithiasis in children with good outcome and acceptable complications.

Risk factors and prediction model of urosepsis in patients with diabetes after percutaneous nephrolithotomy

Objective

To analyze the risk factors of patients with diabetes mellitus (DM) and urosepsis after percutaneous nephrolithotomy (PCNL) for upper urinary tract stones and to develop a nomogram to predict postoperative urosepsis according to the risk factors.

Methods

The data of patients with type 2 diabetes who underwent one-stage PCNL due to upper urinary tract stones were retrospectively analyzed. The risk factors of patients with postoperative urosepsis were evaluated by univariate and multivariate logistic regression analysis, and the nomogram prediction model was developed according to the regression coefficient.

Results

One-stage PCNL was successfully completed in 241 patients with DM, and urosepsis occurred in 41 (17.0%) patients after PCNL. Based on multivariate logistic regression analysis, the independent risk factors associated with postoperative urosepsis included preoperative leukocyte elevation (OR = 3.973, P = 0.005), positive urine nitrite (OR = 3.697, P = 0.010), and positive urine culture (OR = 3.562, P = 0.002). According to the results of the logistic regression analysis model, staghorn stones (OR = 2.049, P < 0.1) and complete intraoperative stone clearance (OR = 0.431, P < 0.1), were used to develop the nomogram. Internal validation of the nomogram showed that the concordance index (C-index) was 0.725. Additionally, the Hosmer–Lemeshow test was performed, P = 0.938 > 0.05.

Conclusion

Preoperative leukocyte elevation, positive urine nitrite, and positive urine culture are independent risk factors for urosepsis after one-stage PCNL for patients with DM with upper urinary tract stones. The nomogram, which is based on independent risk factors that combine stone morphology and intraoperative stone clearance, can help predict the risk of postoperative urosepsis.

Technical aspects to maximize the hyperaccuracy three-dimensional (HA3D™) computed tomography reconstruction for kidney stones surgery: a pilot study

The aim of the current prospective pilot study was to describe a hyperaccuracy three-dimensional (HA3D^™) model reconstruction technique, specifically developed to maximize the visualization of the renal collecting system's anatomy, and its relationship with the stones, vessels and renal parenchyma, and to compare the HA3D^™ virtual models with the intraoperative findings. The image acquisition was performed using a CT scanner (Toshiba, Aquilion Prime) and included the unenhanced, arterial, venous and excretory phases. The DICOM format CT images were processed by MEDICS Srl ( www.medics3d.com , Turin, Italy). In total, study included three patients with renal stone scheduled for non-papillary prone percutaneous nephrolithotomy (PCNL). The median age and BMI were 51 (range 49-54) and 25.5 (range 25.0-32.7), respectively. The median stone size was 1170 mm² (range 830-1520) and median stone density was 1130 HU (range 600-1340). In all cases, the quality of the CT images acquired with our protocol was adequate to perform the HA3D^™ reconstruction. Median operative and puncture time were 39.4 (range 35.2-44.0) and 1.9 (range 1.8-2.1) mins, respectively. The success rate for the first attempt of the percutaneous puncture was 100%, and only one PCNL tract was sufficient to complete the surgery. All three patients were stone-free on the third postoperative day. A dedicated imaging acquisition protocol and a tailored 3D model reconstruction process specifically developed for kidney stones treatment allow obtaining HA3D^™ highly relevant models to greatly match intraoperative findings during PCNL with the potential of minimizing bleeding and organ injury complications.

Classification and standardized reporting of percutaneous nephrolithotomy (PCNL): International Alliance of Urolithiasis (IAU) Consensus Statements

BACKGROUND

The aim of this study was to reach a consensus in the classification and standardized reporting for the different types of PCNLs.

METHODS

The RAND/UCLA appropriateness methodology was used to reach a consensus. Thirty-two statements were formulated reviewing the literature on guidelines and consensus on PCNLs, and included procedure specific details, outcome measurements and a classification for PCNLs. Experts were invited to two rounds of input, the first enabled independent modifications of the proposed statements and provided the option to add statements. The second round facilitated scoring of all statements. Each statement was discussed in the third round to decide which statements to include. Any suggestion or disagreement was debated and discussed to reach a consensual agreement.

RESULTS

Twenty-five recommendations were identified to provide standardized reporting of procedure and outcomes. Consensual scoring above 80% were strongly agreed upon by the panel. The top treatment related outcomes were size of sheath used (99.1%) and position for PCNL (93.5%). The highest ranked Outcome Measures included definition of postoperative hospital length of stay (94.4%) and estimated blood loss (93.5%).

CONCLUSIONS

The consensus statements will be useful to clarify operative technique, in the design of clinical trials and standardized reporting, and presentation of results to compare outcomes of different types of PCNLs.

Outcomes of ultrasound-guided percutaneous nephrolithotomy for the treatment of large stones within non-functioning atrophic kidneys

OBJECTIVES

To evaluate outcomes in patients who underwent total ultrasound-guided percutaneous nephrolithotomy for the management of large stones (>2 cm) within non-functioning atrophic kidneys, and to identify risk factors associated with postoperative persistence of urinary tract infection symptoms in such patients.

METHODS

Between December 2014 and May 2019, 56 patients with large stones within non-functioning atrophic kidneys were treated at Beijing Tsinghua Changgung Hospital, Beijing, China, with total ultrasound-guided percutaneous nephrolithotomy. Factors including age, sex, previous medical history, stone burden, stone composition, stone-free rate, complication rate and postoperative urinary tract infection symptoms were retrospectively evaluated. Uni- and multivariate analyses were carried out to identify risk factors that predict persistence of urinary tract infection symptoms after percutaneous nephrolithotomy in such patients.

RESULTS

The final stone-free rate after auxiliary treatments was 87.5%. The overall complication rate was 17.9%. After a median follow-up period of 12 months (range 6-40 months), three patients (5.4%) ultimately underwent nephrectomy. A total of 44 patients (78.6%) had no symptoms of urinary tract infection during follow up, whereas 63.6% of patients with diabetes continued to show persistent urinary tract infection symptoms at the latest follow up. Five patients (8.9%) showed improved total renal function, while most patients (83.9%) showed a stable estimated glomerular filtration rate. Diabetes was the only factor showing statistical significance in both univariate and multivariate analyses that predicted persistence of urinary tract infection symptoms after treatment with percutaneous nephrolithotomy.

CONCLUSIONS

Ultrasound-guided percutaneous nephrolithotomy is a safe and feasible procedure that can be carried out in patients with large stones within non-functioning atrophic kidneys. However, for such patients with diabetes, percutaneous nephrolithotomy is not recommended.

Embedded upper end of double J stent at the site of renal pelvis injury following percutaneous nephrolithotomy: a rare complication

Background

Injury of the renal collecting system is a well-known complication of percutaneous nephrolithotomy (PNL). Large injuries may cause excessive bleeding and fluid extravasation and require adequate drainage using several modalities such placement of JJ stents. Herein, we report on two cases in which the upper coil of the JJ stent got buried in the fibrous tissues which formed due to an injury of the collecting system during PNL.

Case presentation

40 years old male and 32 years old female underwent standard PNL for partial and total staghorn calculi, respectively. During the procedure in both cases, the renal pelvis was injured. In both cases, JJ stent was used to drain the collecting system. Trial to remove the JJ stent 6 weeks following the procedure failed because the upper coils of the stents were embedded in the fibrous tissues at the perforation site. Laser incision of the fibrous tissues and releasing the upper coil of the stents were performed using percutaneous approach in the first case and flexible ureterorenoscopy (fURS) in the second patient. The procedures were uneventful in both cases.

Conclusion

This is the first report of embedded JJ stents which got buried by fibrous tissues at the site of collecting system injury that occurred during PNL. To prevent this complication in such cases, we suggest draining the collecting system using nephrostomy tube instead of JJ stent. Alternatively, the upper coil of the stent should be placed away from the injury site.

Minimally invasive percutaneous nephrolithotomy (PCNL): Techniques and outcomes

Minimally invasive percutaneous nephrolithotomy (PCNL) was introduced to decrease the morbidity of the standard PCNL (sPCNL). Thereafter, many modifications and techniques have been presented with the introduction of different miniaturized PCNL (mPCNL) techniques, such as micro-PCNL and ultra-mini-PCNL (UMP). As of present, none of the techniques has displaced the sPCNL. Nonetheless, mini-PCNL has continuously widening indications and has been proposed to have significant advantages over sPCNL. In the current review, each technique is presented while discussing the advantages and disadvantages of each approach. A comprehensive review of the current literature has been performed. Articles related to the topic were retrieved and critically analyzed. Less peri-operative bleeding and shorter hospital stay were the most important advantages advocated for mini-PCNL. Although the performance of mini-PCNL is safe, the utilization of micro-PCNL and UMP should be done with caution.

Percutaneous nephrolithotomy for staghorn calculi: Troubleshooting and managing complications

Staghorn calculi comprise a unique subset of complex kidney stone disease. Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for staghorn stones. Despite continuous refinements to the technique and instrumentation of PCNL, these stones remain a troublesome challenge for endourologists and are associated with a higher rate of perioperative complications than that for non-staghorn stones. Common and notable intraoperative complications include bleeding, renal collecting system injury, injury of visceral organs, pulmonary complications, thromboembolic complications, extrarenal stone migration, and misplacement of the nephrostomy tube. Postoperative complications include infection and urosepsis, bleeding, persistent nephrocutaneous urine leakage, infundibular stenosis, and death. In this review, we report recommendations regarding troubleshooting measures that can be used to identify and characterize these complications. Additionally, we include information regarding management strategies for complications associated with PCNL for staghorn calculi.

Treatment of renal calculi without hydronephrosis using a standard channel assisted by a visual puncture system

Objective

To study the safety and efficacy of standard channel establishment using a visual puncture system in the treatment of renal calculi without hydronephrosis.

Methods

We retrospectively analyzed data from 46 patients undergoing percutaneous nephrolithotomy via a standard channel assisted by a visual puncture system, including number of punctures, duration of procedure, hemoglobin level after surgery, calculi clearance rate, and postoperative complications.

Results

Sixty-nine channels were established, including a single channel in 26 cases, double channel in 17 cases, and three channels in 3 cases. The mean number of punctures was 1.50, mean time to establish the standard channel was 2.6 minutes, and duration of surgery was 31.3 minutes. No significant change in hemoglobin was observed after surgery. Forty-three patients had no residual calculi and three had small residual calculi on the day after surgery, representing a first-phase clearance rate of 93.48% (43/46). No significant complications were observed.

Conclusions

Hemorrhage during operation can be significantly reduced by establishing a standard channel using a visual puncture system. Moreover, the number of standard channels can be reduced and the incidence of complications lowered using this approach, which should be adopted widely for the treatment of renal calculi without hydronephrosis.

Intrarenal arteriovenous malformation following flexible ureterorenoscopy and holmium laser stone fragmentation: report of a case

Background

Flexible ureterorenoscopy (FURS) and holmium laser lithotripsy is currently considered as one of the treatment options for large renal calculi. It has been shown to be safer than percutaneous nephrolithotomy. The latter can sometimes be complicated by the formation of intrarenal arteriovenous malformation (AVM). AVM is extremely rare following FURS and laser lithotripsy. Indeed only one case has been reported on reviewing the literature up to June 2018. We report on the second case illustrating the possibility of developing this major complication following this procedure.

Case presentation

A 79 years old diabetic and hypertensive male with stage-4 chronic kidney disease who previously had left extracorporeal shockwave lithotripsy and FURS with Holmium laser lithotripsy, presented with bilateral large renal calculi. He underwent simultaneous bilateral FURS and Holmium laser lithotripsy and was discharged home the following day with almost clear urine. Four days post-discharge, he presented with gross hematuria for which he required hospitalization and blood transfusion. CT scan demonstrated left subcapsular, perinephric and retroperitoneal hematoma. Angiography showed contrast extravasation from pseudoaneurysms in two small branches of left renal artery. Both were selectively embolized with micro-coils and this led to the cessation of the hematuria.

Conclusions

Despite the relative safety of FURS and Holmium laser lithotripsy, it can be associated with major complications like intrarenal AVM. This can probably be prevented by careful and judicious use of laser energy in patients with large stone burden and premorbid conditions.

The Anatomic Structure of a Fused Renal Pyramid and Its Clinical Significance in the Establishment of Percutaneous Renal Access

OBJECTIVE

To explore the clinical significance of the fused renal pyramid (FRP) in establishing percutaneous renal access, and the anatomic basis for avoiding vascular injury caused by puncturing through this renal pyramid with the aim of achieving accurate puncture in percutaneous nephrolithotomy.

MATERIALS AND METHODS

Sixty-two cadaveric kidneys and 105 porcine kidneys were selected for the assessment of regional anatomy, to explore the anatomic structure of the FRP and determine its frequency. Then, we compared the effects of 4 different puncture paths on the occurrence of renal vascular injury when respectively punctured through the normal renal pyramid (group A), the centerline of one side pyramid of the FRP (group B), the center of the entire FRP (group C) and the renal column (group D).

RESULTS

The incidence of FRP in human kidneys is not low. The artery in the kidney can be divided into 6 grades. The grade IV branch-interlobar artery courses through the FRP. There was significant difference in the degree of arterial injury between the group A and C (P = .003), while no significant difference between the group A and B (P = .151). There was significant difference in the proportion of interlolar artery injury between group A and C (P <.001), while no significant difference between group A and B (P = .239).

CONCLUSION

It is necessary to carefully identify and bypass the FRP when establishing a percutaneous renal access. If unavoidable, the puncture path should be on the centerline of one side pyramid of the FRP.

Rigid ureteroscopic lithotripsy versus percutaneous nephrolithotomy for large proximal ureteral stones: A meta-analysis

Object

To compare the safety and efficacy of rigid ureteroscopic lithotripsy (rigid URSL) and percutaneous nephrolithotomy (PCNL) in treating large proximal ureteral stones.

Methods

A systematic search of PubMed, EMBASE, Cochrane Library, and Web of Science databases was performed to find out relevant studies. After literature screening according to the predetermined inclusion and exclusion criteria, data of eligible studies was extracted and then a meta-analysis was conducted via RevMan 5.3 software.

Results

Five randomized controlled trials (RCTs), one prospective and four retrospective cohort studies involving 837 patients were included. Patients underwent rigid URSL were associated with shorter operation time (WMD, -23.66min; 95%CI, −45.00 to -2.32; p = 0.03), shorter hospital stay (WMD, -2.76d; 95%CI, −3.51 to −2.02; p< 0.00001), lower 3rd-day (RR, 0.73; 95%CI, 0.66 to 0.82; p < 0.00001) and 1st-month (RR, 0.82; 95%CI, 0.77 to 0.87; p < 0.00001) stone-free rate, higher risk of conversion to other surgical procedures (RR, 4.28; 95%CI, 1.93 to 9.46; p = 0.0003), higher incidence of migration (RR, 28.49; 95%CI, 9.12 to 89.00; p < 0.00001) and ureteral perforation (RR, 6.06; 95%CI, 1.80 to 20.44; p = 0.004), lower risk of fever (RR, 0.64; 95%CI, 0.42 to 0.97; p = 0.04), transfusion (RR, 0.19; 95%CI, 0.04 to 0.85; p = 0.03) and hematuria (RR, 0.38; 95%CI, 0.25 to 0.57; p < 0.0001). No significant difference was observed in terms of incidence of embolization, pain and ureterostenosis. When cohort studies or studies in which flexible ureteroscopy was used as an intraoperative auxiliary procedure were excluded, we both found that most of the results kept stable.

Conclusions

Both PCNL and rigid URSL are safe for patients with large proximal ureteral stones while PCNL is more effective in stone clearance.

Percutaneous Nephrolithotomy in Rare Bleeding Disorders: A Case Report and Review of the Literature

Surgery in patients with congenital or acquired coagulation defects has always been challenging and requires special care with a multidisciplinary approach. Percutaneous nephrolithotomy (PCNL) is a standard procedure performed in patients with kidney stones. Although prone to bleeding more than most of the widely performed surgical procedures, there are not much data regarding PCNL in patients with bleeding disorders or coagulation defects. There are only case reports or series with a small number of patients for the patients with common coagulation defects, including hemophilias. Moreover, there are no reports about PCNL in rare bleeding disorders. In this study, we reported a case referred for kidney stone treatment and diagnosed as Factor VII deficiency during preoperative evaluation. Because it is one of the rare bleeding disorders, we also reviewed the literature in this field.