Yonghan Peng

Retrograde Intrarenal Surgery Versus Percutaneous Nephrolithotomy Versus Extracorporeal Shockwave Lithotripsy for Treatment of Lower Pole Renal Stones: A Meta-Analysis and Systematic Review

BACKGROUND AND PURPOSE The optimal treatment of patients with lower pole renal stones continues to be a dilemma for urologists. Retrograde intrarenal surgery (RIRS), percutaneous nephrolithotomy (PCNL), and extracorporeal shockwave lithotripsy (SWL) all constitute viable therapeutic options in selected patients. The aim of this study was to assess the efficacy and safety of RIRS, PCNL, and SWL in management of lower pole renal stones. METHODS A literature search was performed in July 2014 using PubMed, Embase, and Web of Science databases. Literature reviewed included meta-analysis and randomized and nonrandomized controlled studies to identify relevant studies for the meta-analysis. RESULTS Six randomized and eight nonrandomized studies were identified for analysis. PCNL provided a significantly higher stone-free rate (SFR) compared with RIRS and SWL. Furthermore, no statistical significant difference was found when PCNL was compared with RIRS and SWL for complication rate. Compared with the other two treatments, RIRS had a longer operative time and PCNL had a longer hospital stay. SWL was associated with significantly higher re-treatment rate compared with RIRS and PCNL, whereas there were no significant differences in auxiliary procedure rates among the three treatment techniques. CONCLUSION RIRS offers a relative higher SFR while it has a longer operative time. PCNL is associated with the highest SFR at the expense of the longest hospital stay. SWL is performed as an outpatient procedure with a relative shorter operative time; however, it has lower a SFR and higher re-treatment rate. The categories of complications vary while the overall complication rates are comparable among the three treatment techniques.

Testosterone and Androgen Receptor in Human Nephrolithiasis

PURPOSE We investigated the relationship of kidney calculi with plasma free and total testosterone, and androgen receptor up-regulation in the kidneys of men with nephrolithiasis. MATERIALS AND METHODS Male patients with kidney stone and healthy men were included in the study. Blood was collected in a tube containing 2% heparin in the morning. Total and free serum testosterone was measured by enzyme linked immunosorbent assay. All patients underwent percutaneous nephrostolithotomy. At the end of the procedure ultrasound guided puncture biopsy was done to acquire kidney tissue. Normal kidney tissue obtained at autopsy served as the control. Androgen receptor was detected in kidney tissue by immunohistochemistry. Stone composition was analyzed in each patient. RESULTS The study included 37 male patients 22 to 39 years old and 31 healthy men 24 to 37 years old. All calculi were composed of calcium oxalate monohydrate or calcium oxalate dihydrate and a few also contained protein or uric acid. Mean±SD serum total and free testosterone was 13.29±4.79 ng/ml and 63.23±28.58 pg/ml in patients, and 7.30±0.82 ng/ml and 35.59±24.91 pg/ml in healthy men, respectively (each p<0.001). Immunohistochemistry revealed androgen receptor up-regulation in the kidneys of patients with nephrolithiasis. CONCLUSIONS Our data suggest the important role of enhanced androgen signaling in human nephrolithiasis.

Reinforcement for Percutaneous Nephrostomy Tubes with a New Technique

BACKGROUND AND PURPOSE Percutaneous nephrostomy (PCN) still plays a significant role in decompressing the renal collecting system. Percutaneous nephrostomy tubes (PNTs), however, which are flexible and may not be protected well by patients, are vulnerable to mechanical drag, although they are carefully fixed to the skin with silk suture. We developed a simple method to reinforce the nephrostomy tube against dislodgement from the skin. PATIENTS AND METHODS A total of 133 adult patients underwent ultrasonography-guided PCN; 85 patients received a conventional method to fix the tubes, while the other 48 patients received a new one. We used a rubber drainage tube, about 2 cm long, sheared longitudinally, as the outer tube to encase the nephrostomy tube, and then sutured the cutting edges together with the skin suture to reinforce the nephrostomy tube. RESULTS Compared with the 85 patients who received the conventional method, there was not any tube dislodgement after PCN in the 48 patients who received the new one at the end of 2 weeks (0 vs 7, P=0.049) and 4 weeks (0 vs 10, P=0.014) follow-up. CONCLUSIONS This is a simple, effective, and inexpensive method that can significantly decrease the dislodgement incidence of PNTs and keep them fixed well after surgery.

The molecular mechanisms of androgen receptor in nephrolithiasis.

OBJECTIVES This study aimed to investigate the molecular mechanisms of androgen receptor (AR) in nephrolithiasis. METHODS Human kidney 2(HK-2) cells were transfected with Lentiviruses expressing AR (DEC-AR), shRNA targeting AR (sh-AR) or the empty vector control using the pLEX lentiviral vector system. The expression levels of AR were measured by qRT-PCR at 72h postinfection, and cells under different treatments were collected for microarray analysis. Differentially expressed genes (DEGs) were identified using Students t-test. The protein-protein interaction (PPI) network was constructed for negatively correlated DEGs using GeneMANIA. Then, functional and pathway enrichment analysis were performed for the genes in the PPI network. RESULTS The qRT-PCR revealed that expression level of AR in DEC-AR cells was obviously increased and decreased in sh-AR cells at 72h postinfection (p<0.05). Totally, 64 negatively correlated DEGs showed lower expressions and 63 negatively correlated DEGs were up-regulated in the DEC-AR HK2 cells. Negatively correlated DEGs were significantly related to cell differentiation, response to stimulus, multicellular organismal process and multicellular organismal development. Pathway enrichment analysis revealed that DEGs mainly participated in the rheumatoid arthritis (CCL2, CSF1, IL11, LTB and MMP1), gematopoietic cell lineage (CD33, CD44, CSF1 and IL11) and TNF signaling pathway (CCL2, CSF1, MMP9 and VCAM1). Meanwhile, CD44, LAMC2 and THBS2 were significantly enriched in ECM-receptor interaction. CONCLUSION The negatively correlated DEGs, especially CCL2, CD44, MMP1 and MMP9, might play critical roles in nephrolithiasis.

Renal function changes after percutaneous nephrolithotomy in patients with renal calculi with a solitary kidney compared to bilateral kidneys

To evaluate renal function changes and risk factors for acute kidney injury (AKI) after percutaneous nephrolithotomy (PCNL) in patients with renal calculi with a solitary kidney (SK) or normal bilateral kidneys (BKs).

Prevention strategies for ureteral stricture following ureteroscopic lithotripsy

Ureteral stricture formation after ureteroscopic lithotripsy is a late complication that can lead to hydronephrosis and a subsequent risk of renal deterioration. The specific incidence is unknown, and the mechanism of stricture formation has not been completely explained. In this review, we summarize the current evidence regarding the incidence of this condition and discuss its pathogenesis. We then list preventive strategies to reduce the morbidity of ureteral strictures.

Calyceal diverticulum mimicking simple parapelvic cyst: a case report.

Calyceal diverticulum is a cystic intrarenal cavity lined by nonsecretory transitional epithelium that communicates with the collecting system via a narrow isthmus or infundibulum. It is a rare anatomic anomaly with an incidence of 0.2% to 0.6% in the patients undergoing renal imaging.1 Single imaging modality usually cannot differentiate calyceal diverticulum from other cystic renal diseases.2 Here, we report a 60-year-old male who was reliably diagnosed with calyceal diverticulum by retrograde urography combined with non-enhanced computed tomography (CT) and magnetic resonance urography (MRU).

High-Power Holmium Laser Percutaneous Nephrolithotripsy for Large Staghorn Stone

Abstract Purpose: To investigate the safety and efficacy of high-power holmium laser (70 W) in percutaneous nephrolithotripsy (PCNL) for large staghorn calculi. Materials and Methods: From December 2004 to March 2008, 438 consecutive patients (456 renal units) with large staghorn stones (diameter ≥4 cm) underwent PCNL with a pulsed holmium:YAG laser using a 1000-μm end-firing optical fiber. For the first 106 patients, a 30 W (3.0 J/pulse and 10 pulse/s) holmium:YAG laser was used for the management of renal stones, whereas for the other 332 patients (Group B), the laser power was set at 3.5 J/pulse with a frequency of 20 pulses/s. For stones in a calyx that were visible with a nephroscope, but unreachable with laser during lithotripsy, the renal mucosa of the calyx was split with 100 W holmium laser to further fragment the stones. Moreover, a porcine mode for the safety of high-power holmium laser was developed. Results: The average stone size was 5.6±0.8 cm in Group A and 5.8±0.8 cm in Group B. All of th...

Impacted Anterior Urethral Calculus Complicated by a Stone-containing Diverticulum in an Elderly Man: Outcome of Transurethral Lithotripsy without Resection of the Diverticulum

INTRODUCTION The prevalence of lower urinary tract symptoms (LUTS) is about 20% in men aged 40 or above. Other than benign prostatic hyperplasia (BPH), urethral diverticulum or calculus is not uncommon for LUTS in men. Surgical treatment is often recommended for urethral diverticulum or calculus, but treatment for an impacted urethral calculus complicated by a stone-containing diverticulum is challenging. MATERIALS AND METHODS An 82-year-old man had the persistence of LUTS despite having undergone transurethral resection of prostate for BPH. Regardless of treatment with broad spectrum antibiotics and an α-blocker, LUTS and post-void residual urine volume (100 mL) did not improve although repeated urinalysis showed reduction of WBCs from 100 to 10 per high power field. Further radiology revealed multiple urethral calculi and the stone configuration suggested the existence of a diverticulum. He was successfully treated without resecting the urethral diverticulum; and a new generation of ultrasound lithotripsy (EMS, Nyon, Switzerland) through a 22F offset rigid Storz nephroscope (Karl Storz, Tuttingen, Germany) was used to fragment the stones. RESULTS The operative time was 30 minutes and the stones were cleanly removed. The patient was discharged after 48 hours with no immediate complications and free of LUTS during a 2 years follow-up. CONCLUSIONS When the diverticulum is the result of a dilatation behind a calculus, removal of the calculus is all that is necessary. Compared with open surgery, ultrasound lithotripsy is less invasive with little harm to urethral mucosa; and more efficient as it absorbs stone fragments while crushing stones.

Re: Markus J. Bader, Christian Gratzke, Michael Seitz, et al. The “All-Seeing Needle”: Initial Results of an Optical Puncture System Confirming Access in Percutaneous Nephrolithotomy. Eur Urol 2011;59:1054–9

In this study, the authors designed a micro-optical system through a specific needle to puncture the kidney calyces [1]. They concluded that the system appears to be most helpful for confirming the optimal percutaneous access to the kidney prior to dilation of the nephrostomy tract, improving the safety of the technique. They speculate that this system could decrease the incidence of bleeding. Percutaneous nephrolithotomy (PCNL) has become an established procedure for renal stones that are large, complex, and resistant to shock wave lithotripsy [2,3]. Technical advances and increasing experience have resulted in considerable refinement of the percutaneous approach to the renal calculi [4,5]. However, PCNL is generally associated with a low but specific complication rate. Bleeding is one of the most important complications, and incidence has been reported to vary between 0.8% and 45% in the literature [2,6,7]. Many other complications develop from the initial puncture, with injury of surrounding organs (eg, colon, spleen, liver, pleura, lung) [6,8,9]. Therefore reducing the complications of PCNL, especially bleeding, is always the research objective of urologists. Previous studies demonstrated that vascular injury in PCNL would induce preoperative bleeding, like arteriovenous fistula (AVF) or pseudoaneurysm [10,11]. Therefore the initial puncture should be along the long axis of the kidney, namely, the relatively avascular territory between the anterior and posterior divisions of the renal artery or the Brödel line, to minimize the risks of major vascular injury [7,12]. In this study, the authors use the ‘‘all-seeing needle’’ to puncture the kidney calyces of 15 patients successfully through the fornix or the papillary tip of a posterior-facing calyx but still under ultrasound, providing the exact angle to locate the needle in the calyces [1]. As we know, that perfect angle is a key point in PCNL for avoiding vascular injury, and the all-seeing needle cannot provide that angle as ultrasound does. In addition, the system cannot help prevent renal parenchyma lacerations. Renal parenchyma lacerations will occur during the dilation of the tract and in terms of stone removal. Inadequate dilation would injure