E. Montanari

Retrograde intrarenal surgery (RIRS), regular and small sized percutaneous nephrolithotomy (PCNL) in daily practice: European Association of Urology Section of Urolithiasis (EULIS) Survey

OBJECTIVEnA wide selection of both anterograde and retrograde mini-invasive procedures exist for stones treatment. The 2016 European Association of Urology (EAU) guidelines still dont univocally define a best option. Our purpose is to give an overview on some European Stone Centers customs and to compare real life clinical practice with statements of opinion leaders and Guidelines.nnnMATERIALS AND METHODSnIn 2015 we performed a survey in 3 step about the spread of retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) techniques among EAU Section of Urolithiasis (EULIS) members. The 1st and 2nd steps dealt with the definition of EULIS urologist and department by collecting personal opinions about the endoscopic techniques. The third step was about clinical results. This paper presents data from the first two steps.nnnRESULTSnNinety-one people answered. Out of them, 80% are European and 42% work in Centres fully dedicated to stone treatment. In particular, 50% of responders perform more than 80 RIRS/year, 25% more than 80 PCNL/year, 48% more than 100 extracorporeal shock wave lithotripsy (SWL)/year. RIRS is mainly used to treat stones < 2 cm both as primary treatment and after SWL failure. 73% dont perform routine pre-stenting and 66% ordinarily use a ureteral sheath. Hospital stay for RIRS is 24h for 70% of responders. Regular PCNL is performed by 87% of the responders, MiniPCNL by 58%, Ultra-MiniPCNL by 23% and MicroPCNL by 28%. Pneumatic balloon dilation is the favourite dilation technique (49%). 37% of responders perform PCNL always in the supine position, 21% always in the prone one. Almost all the responders agree about using Mini, Ultra-Mini and MicroPCNL for 1-2 cm stones. Approximately 50% also use MiniPCNL for stones > 2 cm.nnnCONCLUSIONnour survey confirms the great heterogeneity existing in stones treatment techniques in daily practice.

Retrograde intrarenal surgery using ureteral access sheaths is a safe and effective treatment for renal stones in children weighing <20 kg

INTRODUCTIONnSurgical treatment of pediatric kidney stones has changed dramatically in recent years because of the miniaturization of surgical instruments and the availability of intracorporeal lithotripters. The retrograde intrarenal surgery (RIRS) technique is nowadays considered an effective and safe procedure but studies in very young children are lacking and use of a ureteral access sheath (UAS) has also been debated.nnnOBJECTIVEnTo assess safety and efficacy of RIRS using UAS in children weighing <xa020xa0kg.nnnMATERIALS AND METHODSnData from 13 children weighing <20xa0kg who underwent RIRS for renal stones were collected. A Double-J stent was positioned 14 days before surgery. Demographics, stone location, stone number and composition, stone-free status (SFS) and complications were evaluated. Descriptive statistics were applied to describe the cohort.nnnRESULTSnThirteen patients, age 3.91xa0±xa01.8 years (meanxa0±xa0SD), underwent 16 RIRS. Mean patient weight and stone burden were 14.88xa0±xa03.81xa0kg (range 10-20xa0kg) and 15.5xa0±xa03.8xa0mm (median 16xa0mm), respectively. A UAS was used in 15 out of 16 (93.8%) procedures. SFS was achieved in 81.3% of cases after the first procedure and 100% after auxiliary procedures. Postoperative urinary tract infections with fever (Clavien II) were observed in two (12.5%) patients. Hydrocalyx (Clavien IIIb) was noted in one (6.3%) patient. Patients with stones located in the lower polar calices (pxa0=xa00.024) and with mixed composition (pxa0=xa00.036) had a greater prevalence of complications than those with calculi of other compositions located in other sites. After a mean follow-up of 22.4 months no cases of ureteral strictures or vesicoureteral reflux were observed (Table).nnnDISCUSSIONnThe current findings support previous evidence showing safety and efficacy of RIRS with use of the UAS in pre-stented very young children. In our experience RIRS seems to be an effective and safe option with a stone-free rate of 81.3% and only 1 severe complication (Clavien-Dindo grade IIIb) and no long-term complications. This study is, to date, the first to examine the safety and efficacy of RIRS using UAS for the treatment of intrarenal stones in a selected cohort of pre-school patients weighing <20xa0kg.nnnCONCLUSIONSnRIRS using UAS is an effective and safe procedure for treating kidney stones in pre-school patients weighing <20xa0kg without complications at both short and long term follow up. Stones of mixed composition located in the lower polar calices are associated with a greater risk of postoperative complications.

Intra-operative post-perfusion micro-nephrolithotomy for renal allograft lithiasis: A case report.

Increasing demand drives the expansion of criteria for kidney donation, and nephrolithiasis is now considered a relative contraindication. We report for the first time a case of intra-operative, postperfusion kidney allograft micronephrolithotomy. A 64-year-old man with end-stage renal disease secondary to Alport syndrome underwent primary deceased donor kidney transplantation at our center. Pre-operative ultrasound of the donor identified a 7-mm calculus in the anterior, lower pole calyx. The kidney was extra-peritoneally implanted in the right iliac fossa and reperfused homogenously. Stone retrieval with a flexible ureteroscope failed due to the narrow calyceal infundibulum. Instead, the calculus was removed using the micropercutaneous nephrolithotomy system under ultrasonographic guidance. The calyx was punctured using a 4.85 Fr needle and the stone was fragmented to dust using a Holmium laser. No bleeding was observed. The post-operative course was uneventful. Outpatient follow up demonstrated good function of the graft which was stone free on ultrasound. Postperfusion micropercutaneous nephrolithotomy for kidney allograft calculi offers a safe and feasible option when pre-operative or intra-operative retrograde intrarenal surgery fails.

Pediatric nephrolithiasis: a systematic approach from diagnosis to treatment

Nephrolithiasis is a rare disease in children. For many years children with kidney stones have been managed like “small adults”, but there are significant differences between the pediatric and the adult age in clinical presentation, etiology and treatment. Management of this condition in children has some peculiarities with respect to the adult, as it is often the sign of an underlying metabolic abnormality. Some of these metabolic alterations can lead to serious consequences, such as chronic renal failure, if not adequately diagnosed and treated. Moreover, stones in children with a metabolic abnormality can recur throughout their life, with the need for repeated surgical procedures over the years. So a systematic approach to every child with nephrolithiasis is mandatory to diagnose metabolic defects and establish a personalized therapy. Even the surgical approach in the child has changed significantly over the last two decades: open surgery has now been almost completely replaced by minimally invasive surgery due to the miniaturization of endoscopic instruments and technical advancements in optical and lithotripters systems. The goal is to obtain a stone-free status with the lowest number of minimally invasive procedures and with no complications. Many breakthroughs in our understanding of the physiopathology of renal stones and in surgical technology have been made over the last decades, but the best approach to use in a child with nephrolithiasis remains a true challenge for pediatric nephrologists and urologists.

Clinical utility of computed tomography Hounsfield characterization for percutaneous nephrolithotomy: a cross-sectional study

BackgroundComputed Tomography (CT) is considered the gold-standard for the pre-operative evaluation of urolithiasis. However, no Hounsfield (HU) variable capable of differentiating stone types has been clearly identified. The aim of this study is to assess the predictive value of HU parameters on CT for determining stone composition and outcomes in percutaneous nephrolithotomy (PCNL).MethodsSeventy seven consecutive cases of PCNL between 2011 and 2016 were divided into 4 groups: 40 (52%) calcium, 26 (34%) uric acid, 5 (6%) struvite and 6 (8%) cystine stones. All images were reviewed by a single urologist using abdomen/bone windows to evaluate: stone volume, core (HUC), periphery HU and their absolute difference. HU density (HUD) was defined as the ratio between mean HU and the stone’s largest diameter. ROC curves assessed the predictive power of HU for determining stone composition/stone-free rate (SFR).ResultsNo differences were found based on the viewing window (abdomen vs bone). Struvite stones had values halfway between hyperdense (calcium) and low-density (cystine/uric acid) calculi for all parameters except HUD, which was the lowest. All HU variables for medium-high density stones were greater than low-density stones (pu2009<u20090.001). HUC differentiated the two groups (cut-off 825 HU; specificity 90.6%, sensitivity 88.9%). HUD distinguished calcium from struvite (meanu2009±u2009SD 51u2009±u200916 and 28u2009±u200912 respectively; pu2009=u20090.02) with high sensitivity (82.5%) and specificity (80%) at a cut-off of 35 HU/mm. Multivariate analysis revealed HUDu2009≥u200938.5 HU/mm to be an independent predictor of SFR (ORu2009=u20093.1, pu2009=u20090.03). No relationship was found between HU values and complication rate.ConclusionsHU parameters help predict stone composition to select patients for oral chemolysis. HUD is an independent predictor of residual fragments after PCNL and may be fundamental to categorize it, driving the imaging choice at follow-up.

ADPKD : clinical issues before and after renal transplantation

Autosomal dominant polycystic kidney disease (ADPKD) is the first genetic cause of end-stage renal disease (ESRD) and the number of these patients who are listed for or receive a kidney transplant (KTx) is continuously increasing over time. Hence, nephrologists are involved not only in the handling of ADPKD patients during the long course of the disease, but also in programming and performing a renal transplant. The handling of all these processes implies the complete awareness of a number of critical points related to the decisions to be taken both before and after the transplant intervention. In the present review, we will briefly deal with the main critical points related to the clinical handling of the patients both before and after KTx.