Comparison of Effect of Minimally Invasive Percutaneous Nephrolithotomy on Split Renal Function: Single Tract vs Multiple Tracts

Effect of access sheath diameter used in percutaneous nephrolithotomy on renal function: a prospective randomized study

We aimed to determine the effect of the access sheath diameter used in percutaneous nephrolithotomy (PNL) on renal function. We also investigated the predictors of impaired renal function. Data were prospectively collected from patients who underwent PNL from December 2020 to December 2021. The patients were randomized into two groups according to access sheath diameter: Group 1 (22 Fr, n = 44) and Group 2 (28 Fr, n = 44). Relative renal function (RRF) was calculated by technetium-99 m dimercaptosuccinic acid scintigraphy, and glomerular filtration rate (GFR) was calculated by diethylenetriamine pentaacetic acid scintigraphy. A difference of 5% or more in RRF was considered a significant functional change. Preoperative and postoperative Kidney Injury Molecule-1 (KIM-1) levels were measured. Preoperative demographic data and stone characteristics were similar between the groups. There were also no statistically significant differences between the groups in terms of scar development, changes in RRF, GFR, or KIM-1/creatinine (Cr) (p > 0.05). Significant deterioration in RRF was detected in a total of six (6.8%) patients, three in each group. The factors predicting loss of function were analyzed by regrouping the patients without loss of function as Group A (n = 82) and those with loss as Group B (n = 6). Only stone volume was statistically significant in multivariate analysis (p = 0.002). Access sheath diameter had no significant effect on renal function after PNL. However, the stone volume was found to independently correlate to a loss of renal function after PNL.

2022 Recommendations of the AFU Lithiasis Committee: Percutaneous nephrolithotomy

Percutaneous nephrolithotomy (Labate et al.) is the standard procedure for the treatment of large (≥2cm) kidney stones. The patient can be in prone or modified supine position. The puncture is performed under fluoroscopy and/or ultrasound guidance. The stone-free rate seems to be comparable between miniaturized and standard PCNL. Procedures performed with smaller diameter instruments tend to be associated with significant lower blood loss, but longer procedure times. The limitation of the number of percutaneous tracts results in better preservation of the kidney function and lowers the risk of complications. The use of tranexamic acid during PCNL may be interesting for reducing the bleeding risk, the transfusion rate, and possibly the intervention duration. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU 2022]) and their adaptability to the French context.

Initial Experience of Simultaneous Combined use of Percutaneous Nephrolithotomy and Flexible Ureteroscopy in Complex Renal Calculi: A Novel Surgical Technique of 'Through-Through' Approach

BACKGROUND

For complex branched renal calculi, the endoscopic combined intrarenal surgery (ECIRS) is worldwide prevalent. This study aimed to present a novel surgical technique of percutaneous nephrolithotomy combined with antegrade flexible ureteroscopy which is named 'Through-through' approach.

METHODS

We retrospectively analyzed the data of 68 patients with complex renal calculi who underwent combined PNL and flexible ureteroscopy surgery using 'Through-through' approach at our center between August 2019 and December 2021. The 'Through-through' approach to surgery was indicated in residual calyceal calculi that neither rigid nephroscope nor retrograde flexible ureteroscope could reach. The brief procedure of this technique involved determining the direction of targeted calyces with the nephroscope first, followed by putting flexible ureteroscope into the targeted calyx through the nephroscope instrument channel and basketing or dusting residual calculi through the flexible ureteroscope instrument channel.

RESULTS

The mean maximum stone diameter was 4.0 ± 0.4 cm. The mean operative duration was 100.1 ± 18.0 minutes, and mean hemoglobin loss was 21.4 ± 5.1 g/L. In all 68 patients, calculi were cleared in 62 patients, and the stone free rate was 91.2%. Five patients underwent further surgery after 2 weeks because of significant residual calculi. One patient that had a 6 mm residual stone chose observational follow-up. Ten patients emerged with postoperative fever but did not progress to uroseptic shock. There were no Clavien grade ≥ III complications, and none of the patients required blood transfusion.

CONCLUSION

The 'Through-through' approach is safe, feasible and effective for complex renal calculi patients. It is a complementary solution to the failed endoscopic combined intrarenal surgery.

MINIMALLY INVASIVE PERCUTANEOUS NEPHROLITHOTRYPSY IN THE TREATMENT OF PATIENTS WITH KIDNEY STONES

OBJECTIVE

The aim: To evaluate the outcomes and complications rate of minipercutaneous nephrolithotripsy (MPCNL) for renal stones treatment.

PATIENTS AND METHODS

Materials and methods: MPCNL was performed to 123 patients with kidney stones from January 2020 till November 2021. All operations were performed under endotracheal inhalation anesthesia. After the ureteral catheter was introduced ultrasound controlled punction of kidney collecting system and work channel dilation were performed. Stones were fragmented by holmium laser. The fragments extracted passively with fluid flow through the outer sheath. Operation ended by introduction of nephrostomy tube 14Ch.

RESULTS

Results: In total 135 MPCNLs were performed in 123 patients. The average duration of operations was 55±5,4 minutes and stone size was 1,6±0,2 sm. 12 patients were per¬formed simultaneous MPCNL on both sides. The simultaneous MPCNL duration amounted 105±8,1 min. In 3 (2,2%) cases residual stones were observed. The average hospital stay was 1,31±0,2 days. The renal drainage was removed in 24 ± 3,2 hours after operation. Acute pyelonephritis was presented in 4 (3,3%) and postoperative bleeding in 2 (1,6%) patients, which were stopped by antibacterial and hemostatic drugs with drainage occlusion respectively.

CONCLUSION

Conclusions: To advantages of MPCNL belong short hospital stay, high safety level, insignificant intraoperative and postoperative bleeding, good operation field visualization, opportunity of quick removal of renal drainage, ureteral and urethral catheters. Benefit in patients with severe comorbidities, opportunity of simultaneous bilateral MPCNL and almost complete postoperative pain absence allow to consider MPCNL the operation of choice in kidney stone management.

Comparative assessment of multiple-tract vs single-tract percutaneous nephrolithotomy

INTRODUCTION

To investigate the efficacy and safety of multi-tract percutaneous nephrolithotomy (PNL) against the benchmark of the single-tract approach.

METHODS

A retrospective analysis of 391 consecutive PNL procedures was conducted in our tertiary referral center between April 2016 and March 2020. Clinical outcome parameters such as stone-free rate, operation time, postoperative complications according to Clavien-Dindo, length of hospital stay and time to ipsilateral recurrence resulting in active treatment were assessed.

RESULTS

Multi-tract PNL and single-tract PNL were performed in 37 (9%) and 354 (91%) cases respectively. At baseline, compared to single-tract PNL, multi-tract PNL cases were characterized by significantly larger stone burden (2.62 vs 0.97 cm³ , P < .00), lower Hounsfield units (HU) (751 vs 1017 HU, P < .01), a more complex S.T.O.N.E. (size, tract length, obstruction, number of calyces, essence) score (P < .00) and a higher rate of high-risk stone formers (59 vs 19%, P < .00). Analysis of outcome revealed shorter operation time and length of hospital stay for single-tract PNL compared to multi-tract PNL (P < .01). However, the difference in terms of stone-free rates (92% vs 88%), complication rates (43% vs 28%) and time to active retreatment due to ipsilateral recurrence was not statistically significant (P > .05).

CONCLUSION

In this retrospective single-center analysis, a multi-tract PNL has been proved to be an efficient and safe expansion of single-tract PNL for large stone burden and complex kidney stone disease. Future prospective research should focus on the procedure's potential effectiveness in reducing the number of interventions until stone-free status in patients with massive stone disease.

Comparison of the Prone Split-Leg Position with the Traditional Prone Position in Percutaneous Nephrolithotomy: A Propensity Score-Matching Study

Background and Objective: Several positions have been described for percutaneous nephrolithotomy (PCNL). The aim of this study was to compare the safety and effectiveness of the traditional prone position PCNL (TP-PCNL) and the prone split-leg position PCNL (PSL-PCNL). Patients and Methods: A retrospective review was made of the data of 212 patients who underwent prone PCNL in PSL or TP between January 2017 and November 2019. The demographic and preoperative clinical data were used for propensity score-matching (PSM). Following the PSM based on a multivariable logistic regression model, the PSL-PCNL and TP-PCNL groups were compared in preoperative, perioperative, and postoperative parameters. All surgical procedures were performed by an experienced endourologist. Results: After PSM, 51 patients from the PSL-PCNL group were matched to 51 TP-PCNL patients. The stone burden was not statistically significant between the two groups (p = 0.388). The mean operation time of the two groups was significantly different (81.5 ± 32.4 minutes vs 93.1 ± 25.9 minutes, respectively, p = 0.026). The hemoglobin decrease in the PSL-PCNL group was greater than that in the TP-PCNL group (-17.7 ± 16.9 g/L vs 13.1 ± 10.9 g/L, p < 0.001). Both groups had similar stone-free rates after 2 weeks (p = 0.49). No significant difference was observed between the groups in the total complication rate (p = 1). Conclusions: The application of PSL in PCNL simplifies the surgical procedure and shortens the operating time. Another important advantage is that it allows retrograde intrarenal surgery and ureteroscopy to be performed simultaneously. We recommend the PSL to be applied in PCNL for renal stone patients.

Effect of Endoscopic Ureteral Stone Treatment on Kidney Function

INTRODUCTION

Ureteral stones may have an influence on kidney functions due to postrenal obstruction or urinary infections. Urgent decompression or stone removal is necessary and recommended to prevent further complications in case of severe conditions such as anuria and urosepsis. Although it is believed that ureteral stone removal would result in renal function improvement, there are still unclear points on whether ureteroscopy (URS) can provide benefit as expected and has some adverse effects. In this study, we aimed to evaluate the alteration of kidney functions of patients who undergo rigid or flexible URS for ureteral stones and find if there are any influencing factors on kidney function alteration.

MATERIALS AND METHOD

We analyzed 126 patients who underwent retrograde intrarenal surgery (RIRS) for renal stones between May 2018 and February 2020 prospectively. The estimated glomerular filtration rate (eGFR) was calculated on the day before the surgery, by modification of diet in renal disease (MDRD) formula. The calculation was repeated and saved three times during follow-up for the same patient; on the day after the operation, on the postoperative 30th day, and the postoperative 90th day. Then, we evaluated the renal function by comparing eGFR and assessed the predicting factors affecting the kidney function.

RESULTS

Preoperative mean eGFR was 82.28 ± 25.20 mL/min/1.73 m2 for the study group. Mean eGFR was calculated 90.92 ± 22.97 mL/min/1.73 m2 on the first postoperative day, and 94.54 ± 21.95 mL/min/1.73 m2 on the third-month follow-up. The mean change in eGFR was 8.63 ± 16.68 mL/min/1.73 m2 in the early period and 12.26 ± 21.09 mL/min/1.73 m2 in the long-term follow-up period. Fifty-one patients improved on chronic kidney disease (CKD) stage, and 13 deteriorated in three months follow-up.

CONCLUSION

Removing the stone and relieving the obstruction by ureteroscopic treatment have an alteration on eGFR. Although eGFR improves in the short-term follow-up, amelioration is evident in long-term follow-up, especially in female patients. The other predictive factors for eGFR improvement after URS are the presence of ureteral obstruction and high preoperative serum creatinine levels.

Single- versus Multiple-Tract Percutaneous Nephrolithotomy in the Surgical Management of Staghorn Stones or Complex Caliceal Calculi: A Systematic Review and Meta-analysis

Objective

To assess current evidence on the effectiveness and safety of single- versus multiple-tract percutaneous nephrolithotomy in the surgical management of complex caliceal calculi or staghorn stones through a comprehensive literature review.

Methods

A comprehensive literature review of articles investigating the clinical efficacy and safety of single- versus multiple-tract percutaneous nephrolithotomy was performed. Relevant literature was obtained by systematically searching PubMed, EMBASE, and the Cochrane Library through May 2020. We followed the search strategy based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The primary outcomes, including the stone-free rate (SFR), and secondary outcomes (peri- and postoperative complications and operative data) were evaluated using RevMan 5.3 statistical software.

Results

Ten studies involving 1844 patients with complex caliceal calculi or staghorn stones met the inclusion criteria. Single-tract percutaneous nephrolithotomy (STPCNL) had noninferior clinical efficacy with respect to the immediate SFR (odds ratio (OR) = 0.80, 95% confidence interval (CI) (0.46 to 1.38), p = 0.42) and 3-month SFR (OR = 1.22, 95% CI (0.38 to 3.92), p = 0.74) compared with multiple-tract percutaneous nephrolithotomy (MTPCNL). In addition, pooled analyses showed that STPCNL resulted in significantly lower hemoglobin decreases (MD = −0.46, 95% CI (-0.68 to -0.25), p < 0.0001), fewer blood transfusions (OR = 0.48, 95% CI (0.34 to 0.67), p < 0.0001), and fewer pulmonary complications (OR = 0.28, 95% CI (0.09 to 0.83), p = 0.02) than MTPCNL. However, the overall evidence was insufficient to suggest a statistically significant difference for other adverse events.

Conclusion

This meta-analysis indicated that STPCNL is an effective method for treating complex caliceal calculi or staghorn stones. Compared with MTPCNL, STPCNL not only yields similarly high SFRs but also is associated with many advantages, less blood loss, fewer blood transfusions, and fewer pulmonary complications without an increase in other complications. However, the findings of this study should be further confirmed by well-designed prospective randomized controlled trials (RCTs) with a larger patient series.

Is multiple tract percutaneous nephrolithotomy a safe approach for staghorn calculi?

PURPOSE

To explore the safety of multiple tract percutaneous nephrolithotomy (PNL) in terms of complication and draw a nomogram to predict the possibility of significant renal function decline (SRFD).

MATERIALS AND METHODS

Patients with complex renal calculi appropriate for PNL at our institution between August 2016 and February 2018 were included in the study. The outcome of single and multiple tract PNL was analyzed retrospectively. A nomogram was created to predict the probability of SRFD.

RESULTS

793 (88.4%) patients were treated with single tract PNL (Group 1) and 104 patients (11.6%) treated with multiple tract PNL (Group 2). Group 2 had a significantly greater hemoglobin reduction (16.0 ± 12.5 vs. 11.4 ± 11.8 g/L, p < 0.001), higher rate of postoperative fever (19.2% vs. 11.9%, p = 0.034) and longer duration of the operation (110.6 ± 39.6 vs. 97.8 ± 34.5 min, p < 0.001). A nomogram for predicting the probability of SRFD was constructed based on identified risk factors: patients' age, positive urine culture (UC +), hemoglobin reduction and embolization. The area of receiver operating characteristic (ROC) curve was 70%. Bootstrapping technique utilized to make the calibration plot showed a high reliability of the nomogram.

CONCLUSIONS

Multiple tract PNL had a higher risk of hemoglobin reduction and postoperative fever than single tract PNL. Multiple tracts had no effect on SRFD, but old age, UC + , hemoglobin reduction and embolization were risk factors for SRFD. A nomogram with the aim of predicting the probability of SRFD based on these parameters demonstrated good uniformity in internal validation.

Role of Endourological Procedures (PCNL and URS) on Renal Function: a Systematic Review

PURPOSE OF REVIEW

To present the latest evidence related to the impact of ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) on the renal function.

RECENT FINDINGS

Our review suggests that the overall renal function is not detrimentally affected by endourological interventions (URS, PCNL). This is however influenced by the preoperative renal function, presence of comorbidities such as diabetes and hypertension. For PCNL procedures, tract multiplicity, preoperative UTI, and postoperative bleeding also contribute to a decline in renal function. This review suggests that endourological interventions do not adversely affect renal function and tend to improve it in patients who do not have a poor renal function prior to the procedure. Several factors including poor preoperative renal function, diabetes, hypertension, and multiple percutaneous tracts appear to predispose patients to declining renal function after procedure, and these patients should be counseled for and followed up appropriately.

Kidney volume loss following percutaneous nephrolithotomy utilizing 3D planimetry

Parenchymal damage and renal function impairment following percutaneous nephrolithotomy (PCNL) are of great concern. This study aims to evaluate post-operative changes in renal volume after PCNL. We retrospectively analyzed baseline and post-PCNL CT images from 25 eligible patients from a single tertiary care center. All CT imaging was reviewed using 3D planimetry software (3D Splicer^®, Version 4.0). Segmentation was utilized to obtain total kidney volume (TKV), total kidney surface area, total stone surface area, and total stone volume. Wilcoxon signed-rank test was used for pair analysis, and univariate and multivariable analyses were performed to examine the relationships between clinical and planimetry data and renal volume loss. The median age of the cohort was 62 years, with the majority of the patients having undergone a previous PCNL (52.0%). The median TKV (cm³) pre- and post-PCNL were 225.25 and 178.09, respectively (p = 0.001), with average volume decline of 21%. While there was a statistically significant kidney volume loss in our cohort, there was no difference between pre- and post-operative serum creatinine (mg/dL): 0.93 and 0.94 (p = 0.696), respectively. Multivariable analysis showed a higher TKV loss with a larger kidney stone surface area (OR 1.002, CI 1-1.003, p = 0.035), while younger age was found to be protective (OR 0.791, CI 0.587-0.925 p = 0.028). Patients with previous history of PCNL experiences a more pronounced TKV loss (53.77 cm³, p = 0.031), as compared to PCNL naïve patients (13.05 cm³, p = 0.224). Our study consistently revealed a decrease in TKV following PCNL. Furthermore, among patients with larger stone surface areas, and history of previous PCNL there was an increase in the loss of TKV after the procedure.

Research progress of percutaneous nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is generally accepted as the gold standard treatment for the treatment of large kidney stones (> 2 cm). For nearly 40 years, with the continuous progress of technology and the constant updating of ideas, PCNL has made great progress. In this review, we discuss the current research progress, recent advancement and hot spot of the whole process of PCNL including anesthesia, position, puncture, dilation, lithotripsy approaches, perfusate, tube placement, hospitalization time, drug, treatment of residual stones, prognosis judgment and operation evaluation by summarizing the related research in this article.