Risk factors for hemorrhage requiring embolization after percutaneous nephrolithotomy: a meta-analysis

International Alliance of Urolithiasis (IAU) guideline on staghorn calculi management

BACKGROUND

The stone burden based management strategy reported in the guidelines published by different associations is well known for a long time. Staghorn calculi, representing the largest burden and most complex stones, is one of the most challenging cases to practicing urologists in clinical practice. The International Alliance of Urolithiasis (IAU) has released a series of guidelines on the management of urolithiasis.

PURPOSE

To develop a series of recommendations for the contemporary management management of staghorn calculi and to provide a clinical framework for urologists treating patients with these complex stones.

METHODS

A comprehensive literature search for articles published in English between 01/01/1976 and 31/12/2022 in the PubMed, OVID, Embase and Medline database is performed. A series of recommendations are developed and individually graded following the review of literature and panel discussion.

RESULTS

The definition, pathogenesis, pathophysiology, preoperative evaluation, intraoperative treatment strategies and procedural advice, early postoperative management, follow up and prevention of stone recurrence are summarized in the present document.

CONCLUSION

A series of recommendations regarding the management of staghorn calculi, along with related commentary and supporting documentation offered in the present guideline is intended to provide a clinical framework for the practicing urologists in the management of staghorn calculi.

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.

Mini Percutaneous Nephrolithotomy vs Standard Percutaneous Nephrolithotomy: A Perioperative Decision Support System for Surgical Success Comparison

Purpose

This study aimed to rank the features that are important in terms of safety and effectiveness in choosing the surgical method and providing appropriate care to the patient by using the variables examined before and after the surgery to evaluate the success of mini percutaneous nephrolithotomy and standard percutaneous nephrolithotomy surgeries.

Patients and Methods

The features evaluated before and after surgery were ranked according to their importance in the features considered, using Multivariate Adaptive Regression Splines (MARS), LASSO, Ridge, Elastic_net, and Random Forest algorithms as variable selection techniques. There are 278 samples in the relevant data set.

Results

Type of surgery (100%), intercostal access (97.75%), kidney opening procedure (94.25%), postoperative creatinine (59.22%), hydronephrosis (52.23%), the number of entries (41.61%), and pre- and post-operative hemoglobin difference (45.13%) were determined as the most critical variables. The MARS algorithm showed the most successful performance, with the lowest mean absolute error (MAE) value of 0.3622, the lowest root mean square error (RMSE) value of 0.3960, and the highest R2 value of 0.3405.

Conclusion

Clinical decision support systems can be helpful in eliminating errors and reducing costs. It can also improve the quality of healthcare and aid in the early diagnosis of diseases. Computer-aided decision-making systems can be developed using the results of such products. These systems can provide doctors with better information about their patient's treatment options and improve decision-making. It can contribute to patients being better informed about the surgery results and taking an active role. In conclusion, this study provides essential information that should be included in the surgical decision-making process for patients using medications and with a history of percutaneous nephrolithotomy.

Surgical Delay Increases the Perioperative Blood Transfusion Rate In Percutaneous Nephrolithotomy

Objectives

We aimed to investigate the effect of prolonged time from diagnosis to treatment (TDT) on surgical outcomes in patients undergoing percutaneous nephrolithotomy (PNL).

Methods

This study included a total of 544 patients who underwent PNL in our clinic between November 2017 and November 2021. Clinicodemographical, radiological, and perioperative data of the patients were recorded. The stone-free rate as assessed by abdominal computed tomography at 3 months was estimated. The possible relation of the stone-free rate and perioperative complications with TDT was examined.

Results

The median age was 48 (range, 38-58) years, the median stone size was 405 (range, 250-700) mm2, and the median stone density was 1,000 (range, 730-1,221) Hounsfield units. The median TDT was 75 (range, 42-133) days. Twenty-seven patients (5.0%) required perioperative blood transfusion (PBT). There was a statistically significant correlation between TDT and the need for PBT (p=0.022). However, there was no significant correlation between TDT and stone-free rate (p>0.05). Using a cutoff value of 90.5 days, TDT could predict the need for PBT with 59.3% sensitivity and 60% specificity.

Conclusion

Our study results suggest that the need for PBT increases in patients undergoing PNL longer than 90.5 days after the diagnosis. However, further large-scale, prospective studies are warranted to elucidate the effect of prolonged TDT on surgical outcomes in this patient population.

Renal Pseudoaneurysm with Associated Arteriovenous Fistula as a Cause of Delayed Bleeding after Percutaneous Nephrolithotomy: A Case Report and Current Literature Review

Background

Pseudoaneurysm (PA) with associated arteriovenous fistula (AVF) is a rare delayed bleeding complication, occurring in less than 1% of patients after percutaneous nephrolithotomy (PNL). Case presentation. A 54-year-old man underwent PNL on February 28, 2023, for a large renal calculus in the right kidney lower pole, with postoperative delayed bleeding: macroscopic hematuria and bladder clot retention after 3 weeks. An iatrogenic PA and AVF were diagnosed after the failure of conservative measures. The patient was successfully treated with superselective angioembolization (SAE) under local anesthesia.

Conclusion

Late hemorrhagic complications after PNL can be severe. Rapid identification of a renal PA and AVF with SAE has a high success rate and low complication rate, avoiding prolonged hospitalization time and major renal surgery for this patient.

Endovascular management of post PCNL vascular injuries

Although percutaneous nephrolithotomy (PCNL) is a gold standard treatment of large kidney stones, vascular injuries like pseudoaneurysm (PA) and arteriovenous fistula (AVF) may occur due to renal punctures. These endovascular complications need urgent intervention to be diagnosed and managed early. In this case series, 14 patients who had hematuria after PCNL were managed by using angiography to identify the vascular pathology. Among them, we identified 10 patients with PA and 4 patients with AVF, 1 patient with both subscapular hematoma and PA. Angiographic embolization was done successfully in all patients. Based on our results, in cases with peripheral parenchymal damage, PA was common and in cases with hilar damage, AVF was common. No other complication and rebleeding was detected after embolization. Based on our study, angiography can be used as a safe and effective method to detect and treat vascular injuries immediately and successfully.

The effects of continuing aspirin on blood loss and postoperative outcomes in percutaneous nephrolithotomy

BACKGROUND

Percutaneous nephrolithotomy (PCNL) is an effective surgery for complex kidney stones yet with inherent bleeding risks. It remains unclear whether aspirin should be discontinued prior to PCNL. We aimed to further substantiate the safety of continuing aspirin during PCNL surgery and to determine whether aspirin status affects postoperative outcomes following PCNL.

METHODS

We retrospectively queried our endourology database for patients who underwent PCNL from October 2017 to December 2022 at our high-volume tertiary referral center. The three groups were based on aspirin status at the time of PCNL: no aspirin (NA), discontinued aspirin (DA), and continued aspirin (CA). Data collected included demographics, preoperative characteristics, operative parameters, pre and postoperative lab values, transfusions, and complications.

RESULTS

A total 648 patients were divided into these study groups: 525 NA patients (81.0%), 55 DA (8.5%), and 68 CA (10.5%). The DA and CA groups were of similar comorbidities, and both were more comorbid at baseline than NA. Postoperative change in lab values and complications did not differ significantly. Rates of postoperative blood transfusion were higher in the CA and DA groups compared to NA and approached statistical significance. There were no significant differences in any postoperative outcomes between the DA and CA groups alone.

CONCLUSIONS

In patients on chronic aspirin therapy, continuing aspirin appears equally safe to discontinuing aspirin prior to PCNL. Most patients should not forego the benefits of continuous aspirin for the theoretical risk of bleeding. Patients on prolonged aspirin therapy may be more likely than those who are not on chronic aspirin therapy to require blood transfusions. However, regardless of whether aspirin use is stopped, this may be caused by patient comorbidities rather than higher rates of blood loss.

International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNLs. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs.

Risk Factors for Intra-operative Bleeding in Percutaneous Nephrolithotomy in an Academic Center: A Retrospective Study

Background

Percutaneous nephrolithotomy (PNL) is the treatment of choice for renal stones as a safe, effective, and minimally invasive method. However, bleeding remains a major concern in the procedure.

Objectives

This study aimed to investigate the risk factors of bleeding in PNL.

Methods

This retrospective descriptive cross-sectional study was conducted in the Urology department of Razi hospital. The data of patients with urinary calculi staghorn type who underwent PNL in a prone position under general anesthesia were recorded. A checklist including patients' demographics, surgical characteristics, and outcomes was filled out for each patient.

Results

The data from 151 complete files were gathered. The mean age of the cases was 47.89 ± 12.41 years. The mean hemoglobin (Hb) drop was 1.92 ± 1.56 mg/dL. At least 1 mg/dL Hb drop was observed in all cases. The highest Hb drop was 3 mg/dL.). There was no significant relationship between stone bulk, age, BMI, GFR, surgery duration, and the number of tracts, and Hb drop during PNL (P > 0.05). But there was a positive correlation between Urinary Tract Infection (UTI) history (P = 0.01) and transfusion (P = 0.0001) and Hb drop during PNL. Also, the history of open kidney surgery (P = 0.031), nephrostomy insertion (P = 0.003), and extracorporeal shock wave lithotripsy therapy (ESWL) (P = 0.041) were correlated with the increased risk of Hb drop.

Conclusions

Urinary tract infection, history of open surgery, nephrostomy implantation, and ESWL were significantly associated with more bleeding in PNL.

Pre-Operative Parameters Predicting Hemoglobin Decline Related to Percutaneous Nephrolithotomy

Objectives

Percutaneous nephrolithotomy (PNL) for upper urinary tract stones is a minimally invasive, effective treatment modality. Despite its high success rates, its potential complications pose a risk. In this study, we aimed to determine the risk factors associated with bleeding which is one of PNL's most important complications.

Methods

The data of patients who underwent PNL between January 2017 and December 2018 were retrospectively analyzed. The median reduction in post-operative hemoglobin levels compared to preoperative levels was found to be 1.6 g/dl, which was accepted as the threshold value. The patients with hemoglobin decrease above the threshold were assigned as Group 1, and below the threshold as Group 2. Pre-operative, perioperative data, and stone characteristics of the patients were recorded.

Results

169 patients, 85 patients in Group 1 and 84 patients in Group 2 were included in the study. The mean age of Group 1 was significantly higher (47.4±7.9 and 32±9.4 years, respectively, p=0.001) Sixteen in Group 1 (18.8%) and six in Group 2 (7, 1%) had a diagnosis of hypertension (HT) and a significant difference was found (p=0.038). The average stone burden was 2733±1121.3 mm3 in Group 1, and 2326.5±975.6 mm³ in Group 2. It was observed that there was a significantly higher stone burden in Group 1 (p=0.001). There was a significant difference between the groups in terms of mean operation time (84.4±7 and 76.2±9.9 min, respectively, p<0.001). When the complication rates were analyzed, complications were observed in 25 (29.4%) patients in Group 1 and 12 (14.2%) patients in Group 2, and a significant difference was found between both groups (p=0.019). Age and HT were found to be significant independent risk factors associated with hemoglobin decline in multivariate analyzes (p<0.001 and p<0.027, respectively).

Conclusion

In this study; advanced age, presence of HT, and high stone burden were found to be predictive of reductions in hemoglobin levels. Furthermore, a correlation of decreased hemoglobin levels was detected with operative times and occurrence of complications.

No staghorn calculi and none/mild hydronephrosis may be risk factors for severe bleeding complications after percutaneous nephrolithotomy

Background

To explore the risk factors for severe bleeding complications after percutaneous nephrolithotomy (PCNL) according to the modified Clavien scoring system.

Methods

We retrospectively analysed 2981 patients who received percutaneous nephrolithotomies from January 2014 to December 2020. Study inclusion criteria were PCNL and postoperative mild or severe renal haemorrhage in accordance with the modified Clavien scoring system. Mild bleeding complications included Clavien 2, while severe bleeding complications were greater than Clavien 3a. It has a good prognosis and is more likely to be underestimated and ignored in retrospective studies in bleeding complications classified by Clavien 1, so no analysis about these was conducted in this study. Clinical features, medical comorbidities and perioperative characteristics were analysed. Chi-square, independent t tests, Pearson’s correlation, Fisher exact tests, Mann–Whitney and multivariate logistic regression were used as appropriate.

Results

Of the 2981 patients 70 (2.3%), met study inclusion criteria, consisting of 51 men and 19 women, 48 patients had severe bleeding complications. The remaining 22 patients had mild bleeding. Patients with postoperative severe bleeding complications were more likely to have no or slight degree of hydronephrosis and have no staghorn calculi on univariate analysis (p < 0.05). Staghorn calculi (OR, 95% CI, p value 0.218, 0.068–0.700, 0.010) and hydronephrosis (OR, 95% CI, p value 0.271, 0.083–0.887, 0.031) were independent predictors for severe bleeding via multivariate logistic regression analysis. Other factors, such as history of PCNL, multiple kidney stones, site of puncture calyx and mean corrected intraoperative haemoglobin drop were not related to postoperative severe bleedings.

Conclusions

The absence of staghorn calculi and a no or mild hydronephrosis were related to an increased risk of post-percutaneous nephrolithotomy severe bleeding complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00866-9.

European Association of Urology Section of Urolithiasis and International Alliance of Urolithiasis Joint Consensus on Percutaneous Nephrolithotomy

CONTEXT

Although percutaneous nephrolithotomy (PCNL) has been performed for decades and has gone through many refinements, there are still concerns regarding its more widespread utilization because of the long learning curve and the potential risk of severe complications. Many technical details are not included in the guidelines because of their nature and research protocol.

OBJECTIVE

To achieve an expert consensus viewpoint on PCNL indications, preoperative patient preparation, surgical strategy, management and prevention of severe complications, postoperative management, and follow-up.

EVIDENCE ACQUISITION

An international panel of experts from the Urolithiasis Section of the European Association of Urology, International Alliance of Urolithiasis, and other urology associations was enrolled, and a prospectively conducted study, incorporating literature review, discussion on research gaps (RGs), and questionnaires and following data analysis, was performed to reach a consensus on PCNL.

EVIDENCE SYNTHESIS

The expert panel consisted of 36 specialists in PCNL from 20 countries all around the world. A consensus on PCNL was developed. The expert panel was not as large as expected, and the discussion on RGs did not bring in more supportive evidence in the present consensus.

CONCLUSIONS

Adequate preoperative preparation, especially elimination of urinary tract infection prior to PCNL, accurate puncture with guidance of fluoroscopy and/or ultrasonography or a combination, keeping a low intrarenal pressure, and shortening of operation time during PCNL are important technical requirements to ensure safety and efficiency in PCNL.

PATIENT SUMMARY

Percutaneous nephrolithotomy (PCNL) has been a well-established procedure for the management of upper urinary tract stones. However, according to an expert panel consensus, core technical aspects, as well as the urologist's experience, are critical to the safety and effectiveness of PCNL.

Definition and Unfavorable Risk Factors of Trifecta in Mini-Percutaneous Nephrolithotomy

Objectives: In performing mini-percutaneous nephrolithotomy (PCNL), we aimed at achieving the trifecta of stone-free status and no complications in a single treatment session. We analyzed our experience to determine negative predictors for achieving these three-fold goals. Patients and Methods: The data of all consecutive patients who underwent tubeless mini-PCNL between July 2015 and March 2020 in two hospitals were retrospectively reviewed. Stone-free was defined as no residual stones. Complications were recorded and graded according to modified Clavien classification. Patients were divided into two groups according to the outcome (trifecta and non-trifecta). Factors affecting the outcome were compared between both groups by using univariate and multivariate analyses to detect independent unfavorable risk factors. Results: The study included 944 patients with mean age 40.2 years (standard deviation: 13.6). The stone-free rate after one session of mini-PCNL was 90.7%. Auxiliary procedures were needed in 14 patients (1.5%). Complications were observed in 76 patients (8.1%). Trifecta was achieved in 792 patients (84%). Independent unfavorable risk factors in multivariate analysis were number of caliceal groups affected by the stones (relative risks were 1.95 to 2.27 and 5.7 for one, two, and three caliceal groups respectively) and number of percutaneous tracts (relative risk was 2.2). Stone size and complexity were not significant predictors of missing trifecta in multivariate analysis. Conclusions: Mini-PCNL can achieve a high rate of trifecta (84%) for different stone sizes and complexities. Stones distribution in multiple caliceal groups and multiple tracts are the independent unfavorable risk factor.

Suctioning semirigid ureteroscopic lithotomy versus minimally invasive percutaneous nephrolithotomy for large upper ureteral stones: a retrospective study

Background

To compare the safety and validity of a suctioning semirigid ureteroscopic lithotomy (Sotn-URSL) and minimally percutaneous nephrolithotomy (mPCNL) in treating upper ureteral stone larger than 15 mm.

Methods

Between February 2018 and December 2019, 97 patients who had upper ureteral stone >15 mm were consecutively included in this study. Forty-six patients underwent Sotn-URSL and 51 underwent mPCNL by the same surgeon. The following parameters were retrospectively assessed: patient and stone characteristics, surgical details, perioperative outcomes, and stone-free rates (SFRs).

Results

No significant difference was observed in two groups for patient and stone characteristics, except that mPCNL group had a higher incidence of severe hydronephrosis (19.6% vs. 41.2%, P=0.021). Sotn-URSL group was similar to mPCNL group in terms of the mean duration of surgery (50.5±5.9 vs. 52.9±8.0 min, P=0.106) and the SFR after 1 month (91.3% vs. 98%, P=0.187). The hospital stay after surgery of Sotn-URSL group was significant shorter than mPCNL group (1.4±0.6 vs. 2.3±0.7 days, P<0.001), and postoperative complications in Sotn-URSL group was less, especially postoperative pain (P=0.044).

Conclusions

Both mPCNL and Sotn-URSL are suitable for upper ureteral stones with a diameter of >15 mm. Nevertheless, further well-designed studies with long-term follow-up are needed to confirmed the results.