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Renal lithiasis is one of the most commondisorders in modern society, constituting an importanthealth problem that associates a great economic burden.The nature of stone disease varies according to ageand sex, being also influenced by dietary and lifestylefactors, and climatic variations among others. In spite ofthe advances made in the management of this pathology,it continues being a disease with a high recurrence rate.In recent years, several studies have pointed out that itsprevalence is rising especially in developed countries.This increase seems to be fundamentally due to changesin dietary habits and lifestyle, although other factors suchas migratory flows from rural areas to major cities, and arise in global temperatures may also be involved.In the present article, we discuss the main factors thatseem to influence today the epidemiology of urinarylitiasis, as well as the aforementioned increase ofprevalence.
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There are two basic pathways for formation of calcium based kidney stones. Most idiopathic calcium oxalate (CaOx) stones are formed in association with sub-epithelial plaques of calcium phosphate (CaP), known as Randall’s plaques, on renal papillary surfaces. Crystal formation and retention within the terminal collecting ducts, the ducts of Bellini, leading to the formation of Randall’s plugs, is the other pathway. Both pathways require supersaturation leading to crystallization, regulated by various crystallization modulators produced in response to changing urinary conditions. High supersaturation, as a result of a variety of genetic and environmental factors, leads to crystallization in the terminal collecting ducts, eventually plugging their openings into the renal pelvis. Stasis behind the plugs may lead to the formation of attached or unattached stones in the tubular lumen. Deposition of crystals on the plug surface facing the pelvic or tubular urine may result in stone formation on the Randall’s plugs. Kidneys of idiopathic stone formers may be subjected to oxidative stress as a result of increased urinary excretion of calcium/oxalate/phosphate and/or decrease in the production of functional crystallization inhibitors or in relation to co-morbidities such as hypertension, atherosclerosis, or acute kidney injury. We have proposed that production of reactive oxygen species (ROS) causes dedifferentiation of epithelial/endothelial cells into osteoblast type cells and deposition of CaP in the basement membrane of renal tubules or vessels. Growth, aggregation and melding of CaP crystals leads to the formation of plaque which grows by further calcification of interstitial collagen and membranous vesicles. Plaque becomes exposed to pelvic urine once the covering papillary epithelium is breached. Surface layers of CaP are replaced by CaOx through direct transformation or demineralization of CaP and mineralization of CaOx. Alternatively, or in addition, CaOx crystals nucleate directly on the plaque surface. Stone growth may also depend upon supersaturation in the pelvic urine, triggering further nucleation, growth and aggregation.
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Urinary lithiasis is a prevalent disorder ofuncertain origin which provokes health problems throughpotential harm to the urinary system, renal parenchymaor the body as a whole, with a frequent trend to relapse.Historically urinary calculi have been studied andtreated as an isolated disease but nowadays we knowmore about their connection with other pathologicalentities. In a small percentage of patients, diseases likeprimary hyperparathyroidism, tubular renal acidosis,inflammatory bowel disease or bariatric surgery havea fairly well studied physiopathological link withkidney stones. However, papers have been publishedrecently describing connections between prevalentdiseases such as bone disease or metabolic syndromeand nephrolithiasis. Attempts to prevent or treat theseaffections can possibly influence the other´s prevalencesince their trend to increase is clear in western countries.
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In this review, we analyze the etiopathogenic principles of urinary lithiasis formation. In the kidney, calcifications that may cause renal lithiasis are produced as a consequence of processes that injury the urothelium at the papilla and Bellini´s ducts. With the improvement of imaging techniques, mainly micro CT scan, it is possible to detect them and we may be able to anticipate to the formation of lithiasis. As we well know, there are different factors that influence the formation of the calculi depending on their composition. In calcium lithiasis it is key to review the modification of the categories of hypercalciuria, we currently distinguish two types instead of three, thanks to the fasting calcium/ creatinine ratio, differentiating absorptive hypercalciuria and fasting hypercalciuria. In the fasting hypercalciuria, it is important to emphasize the relationship between this factor and the loss of bone mineral density in patients with recurrent renal calcic lithiasis, so that in this kind of patients it is compulsory the study of bone metabolism by bone remodelling markers and bone densitometry. Regarding the other factors that participate in the formation of calcium lithiasis we should specially emphasize on hypercalciuria and its growing increase because of its relationship with obesity and metabolic syndrome, as well as hipocitraturia, present in an important percentage of patients and related in some cases with metabolic acidosis and osteopenia-osteoporosis too. In relation to uric acid lithiasis it should be highlighted that urinary pH is the most determinant factor and, therefore, its control and modifications would be paramount for prevention of this type of lithiasis. In the infectious lithiasis, the presence of germs that split urea is mandatory. They generate ammonia ions with the ability to injure the urothelium and to form magnesium ammonium phosphate lithiasis mainly. Regarding cystine lithiasis, rare, it was classically divided in three types and now passed to be classified in type A and B depending on the muted gene, and it is more useful to perform direct 24-hour urine measurement than screening tests which have low sensitivity. In general, we tried to give a comprehensive view of the various types of lithiasis emphasizing the most interesting clinical points for the urologist.
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Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime- estimated recurrence risk of over 50%. Imaging techniques play a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. The are many useful tools for diagnosing urolithiasis, including conventional plain radiography, intravenous urography, ultrasonography, computed tomography and magnetic resonance imaging. All these techniques have their own individual roles to play and also their limitations. Radiological management will depend on the tools available at the center and on the characteristics of the patient. Non-contrast enhanced CT scan has high sensitivity and specificity, although concerns about radiation exposure and costs remain. It is essential to use computed tomography techniques that minimize radiation and to use alternatives like ultrasonography, or magnetic resonance imaging in pregnant patients and children. There is no evidence to support strong recommendations regarding the frequency and type of imaging for follow-up of patients with urolithiasis (treated or under observation). The objective of this article is to review the imaging pathway for comprehensive stone management.
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Risk factors should be evaluated in all patients with urinary lithiasis. The kind of evaluation, simplified or extended, depends on stone composition and, in patients with calcium lithiasis, on the clinical presentation. These studies are done in an outpatient regimen, are easy to perform and accessible for most laboratories. Patients with uric acid, infectious and cystine stones only require a selective more abbreviated evaluation. In calcium lithiasis we perform an extended metabolic evaluation in recurrent patients and also in single- episode patients when they have high recurrence risk. The extended evaluation has demonstrated to be cost- effective in patients with highly recurrent lithiasis. There is not enough clinical evidence yet on what would be the most convenient study methodology for a proper metabolic evaluation, and proposed clinical guidelines are mainly based on expert committee opinions. With these studies, we can diagnose systemic and renal diseases of lithogenic nature, and they also enable the adoption of precise prophylactic measures that achieve recurrence control in a great number of patients.
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Renal calculi are generally formed as a result of the combination of certain factors, some related to urine composition (concentration of lithogenic substances, deficiency of crystallization inhibitors, presence of heterogeneous nucleants) and others with renal morphology and anatomy (urinary tract stasis, low urodynamic efficiency cavities, morpho-anatomic deformations, renal papillary tissue lesions). In fact, the composition, macrostructure and microstructure of the calculus will clearly depend on the factors that have induced it. For this reason, the appropriate study and classification of the renal calculi simplifies the diagnosis and allows a more effective therapeutic approach since it can be oriented to directly correct the etiological factors responsible for stone formation. In this article, we review the main etiological factors involved in the formation of each type of calculus and the prophylactic measures that can be adopted for proper correction. The most frequent kidney stones have been classified into the following types: calcium oxalate monohydrate papillary calculi, calcium oxalate monohydrate non-papillary calculi, calcium oxalate dihydrate calculi, mixed hydroxyapatite/calcium oxalate calculi, carboxyapatite/hydroxyapatitecalculi, brushite calculi, struvite/carboxyapatite calculi, uric acid calculi, uric acid/calcium oxalate monohydrate calculi, and cystine calculi. Occasionally, however, the calculus is not available for study, in which case the only way forward is to use all available information (clinical history, life habits, radiological data), together with basic biochemical information, to identify and correct all etiological factors related to renal lithiasis that have been identified.
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The incidence and prevalence of lithiasicdisease in developed countries has increased over thelast years. Being diet one of the risk factors for urolithiasis,and having it evolved in conjunction with lifestyleover the last decades, such changes could explain theincrease in lithiasis case-load.In this article, we analyze how the exercise of the urologisthas been regarding the preventive role of diet in thelithiasis patient, what are the scientific evidences on therelationship of diet and lithiasis, and, on this base, whatgeneral dietetic recommendations we can give currentlyto our patients.
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OBJECTIVE: An update of the new treatment strategies in extracorporeal lithotripsy as a valid therapeutic alternative in the management of urinary calculi.METHODS: We performed a search and review of the most recent literature which responded to the terms “best practices”, “update”, “optimization”, “practice pattern” in lithotripsy. Only articles written in English or Spanish were selected. RESULTS: The use of a stepwise voltage ramping during extracorporeal lithotripsy with or without pause before the first rise of energy, a decreased delivery rates and the use of a higher number of shock waves per session are shown as alternatives to improve the effectiveness with optimum safety profile.CONCLUSIONS: Extracorporeal lithotripsy is still an effective and minimally invasive treatment, and it has an important role in the treatment of urolithiasis. New treatment strategies are being developed to increase the effectiveness with a similar safety profile.
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INTRODUCTION: The contribution of therapeutic ureteroscopy done by Perez Castro in 1980 varied the management algorithm for ureteral lithiasis worldwide. The techniques of Retrograde Ureteroscopy and transrenal antegrade ureteroscopy led to the abandonment of open surgery for the treatment of ureteral lithiasis. Only Shock wave lithotripsy has maintained similar success rates in selected cases.METHODS: Descriptive analysis of the semirigid and flexible ureteroscopy techniques performed in our department over the last 10 years giving detail on the technique and safety tips to increase the efficacy and efficiency of ureteroscopy. 4,533 semirigid ureterorenoscopies and 980 flexible ureterorenoscopies were performed between January 2005 and July 2016.RESULTS: We registered 82% lithiasis elimination on a single operation with a 1,8% overall complication rate for complications higher than Clavien III. We registered 108 urinary sepsis episodes with 2 deaths secondary to massive shock. One patient required supra-selective renal embolization due to renal rupture and hemorrhage after URS. Four patients have required open or laparoscopic surgical repair Five patients required nephrectomy due to absent function of the renal unit after URS and 2 for complete ureteral avulsion on ureteroscope extractionCONCLUSIONS: Semirigid ureterorenoscopy enables the elimination of ureteral lithiasis on a major ambulatory surgery regimen with an acceptable complication rate and a low rate of ancillary measures.Flexible ureteroscopy has resolved intrarenal lithiasis of up to 2 cm, being a substitute for percutaneous nephrolithotomy for these cases
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Micro-ureteroscopy is a novel techniquederived from the need to reduce the morbidity associatedwith conventional ureteroscopy. Reducing morbidity,we will be able to improve quality of life of patients, forexample, by shortening the times to elimination of thestones. In this article the authors intend to expose thedifferent applications of micro ureteroscopy as well asthe incipient scientific evidence on the topic.
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Flexible ureteroscopy is a highly resolving surgery which is able to solve most renal lithiasis of any Urology Department, with very low economic impact. It is a technique that has helped to continue treatment when SWL couldn´t, and also has reduced the number of percutaneous renal surgeries that we currently perform. In this paper, we try review three important features of the operation: Technique, minimal requirements that we need to perform this surgery in a Urology Department, and the different possibilities to treat the lithiasis with holmium laser. We want to show how to perform the surgery successfully and advise what instruments and other surgical materials we really need to purchase. It is totally proved that this is a minimal invasive technique, with reasonably low cost and highly effective.
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OBJECTIVES: The objective of this article is to show the current situation regarding two surgical techniques for the treatment of renal lithiasis, RIRS (Retrograde intrarenal surgery) and PCNL (Percutaneous nephrolithotomy), specially concerning the larger size stones. We perform a literature review on the topic and add the experience with both techniques at our center. Besides, we also analyze the role of RIRS in comparison with the percutaneous techniques in smaller size lithiasis. METHODS: We review the results obtained in the literature and our experience. We offer our opinion in reference to the indications of RIRS in these cases based on such review and our experience.RESULTS/CONCLUSIONS: RIRS is a safe and effective technique, with a similar success rate to PCNL if one assumes the possibility of retreatment in stones >2cm. Its low complication rate, fast postoperative recovery and short hospital stay make this technique a therapeutic alternative to PCNL in this type of patients.Compared with percutaneous techniques less invasive than classical 24 to 30 Ch. accesses (miniperc or microperc), RIRS offers a higher stone free rate. If we also consider that RIRS is associated with shorter hospital stay and lower bleeding risk, even without significant differences in the global complication rate we could consider RIRS as the first line endourological treatment in stones >2cm.
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The creation of the access is one of the main steps in percutaneous nephrolithotomy, the most complicated for many urologists and the one that limited most the universalization of the technique. From a purely technical point of view, it includes puncture of the excretory tract and dilatation of the percutaneous tract to end with the introduction of an Amplatz type working sheath. The objective of the puncture is to try to access the excretory system through the renal papilla, minimizing the risk of bleeding. The puncture may be guided by ultrasound, fluoroscopy, both, under endoscopic or laparoscopic control, by CT scan or MRI, or even by application of new technologies (Robotic, augmented reality, electromagnetic navigation,…). Due to the versatility and independence involved in having the ability to perform the renal puncture in the operative room, as well as its influence in the results of PCNL, it must be the urologist himself who performs this basic step of percutaneous surgery. The tract may be dilated by Alken type metallic dilators, semirrigid Amplatz type dilators or high pressure balloons. To date, there is no single ideal dilatation method, being the selection based on the endourologist´s experience and the knowledge of the advantages and limitations of each option.The objective of this review is to present the main methods for puncture guiding and tract dilatation for PCNL, as well as to provide technical details to improve its result.
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OBJECTIVE: To describe the PCNL technique addressing those conditions that enable us to perform the procedure with maximum patient`s safety without losing focus on the objective of lithiasis resolution.METHODS: Based on our experience, accumulated with time, and the constant update of the endourological techniques we treat those issues in relation to PCNL from the efficiency, efficacy and effectiveness perspective. To consider them involves the successful performance of the technique, with complications prevention and taking cost-efficiency into account. The first one is in close connection to selection of the most adequate technique for each case, training and team work to achieve excellence. With meticulous preoperative preparation and procedure performance, on every single step of the operation, we will ensure an effective technique, avoiding complications. Efficiency comes from the two first and involves, in addition to perform a successful and safe procedure, that the procedure should be cost effective from the management point of view.CONCLUSIONS: PCNL offers the possibility of endoscopic extraction of renal lithiasis, regardless of its volume, density or site, but its success, safety and efficiency are closely linked to the possibility of establishment of an appropriate tract that enables manipulation and total extraction of the calculus.
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Stone disease has afflicted mankindsince centuries; records from ancient civilisations ofIndia and Egypt have shown stones in human bodies.The scientific mind of humans has always made smartendeavours to remove the kidney stones. From largeinstruments made like the beaks of different animalsand birds in 600 BC (Indian civilisation) to extremelysophisticated and miniaturised endoscopic intrumentsof today the human race has travelled a long way.The theme has always been to remove the stones withminimal morbidity and mortality and with minimum painto the patient. The article takes you through the journeyof instruments used in 600 BC until today. The story ofinstrumentation is a symbiosis of the medical minds alongwith engineering advances. The story of miniaturisationcould not have moved further without the developmentof lasers, fiberoptics and sophisticated cameras. As thefield stands today, we remove more complex stones by larger endoscopic intervention and smaller stones byminiaturised instruments. The article discusses all themerits and shortcomings of various techniques: fromopen surgery to standard PCNL to Mini PCNL to Ultra-Mini PCNL to Micro-PCNL.
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Ultra mini PCNL (UMP) has been described as a less invasive technique of PCNL for the treatment of small to medium sized stones in attempt to reduce the surgical morbidity.OBJECTIVE: Evaluate prospectively the outcomes of UMP.METHODS: Single surgeon prospective concurrent cohort study of UMP in India.Effectiveness was assessed by stone-free rates, operative time, complications including transfusion, sepsis rates, length of stay and analgesic requirements. RESULTS: In 2013, data on 98 consecutive patients who underwent UMP was collected prospectively. Mean stone size (±SD) was 15.85 ± 4.53mm. The mean Hounsfield unit (HU) was 1105 ± 165HU. Access to the kidney was from the upper pole (8), interpolar (36) and lower pole (55) with no instances of failed access. Mean operating time was 54 minutes (range 28-120 minutes). The mean change in haemoglobin was -0.81g/dl and mean change in creatinine was 0.05mg/dl. No patients were transfused or suffered acute kidney injury. There were fiveClavien-Dindo complications (Grade I x4, IIIb x 1) with the most serious being a perinephric collection requiring intervention.Post-operative oral analgesia was sufficient in 89 patients (91%) with 9 patients (9%) requiring IM or IV analgesia. Median length of stay was 30 hours (IQR 10 hours). 13 patientshad nephrostomy drainage. 8 patients required a stent for one week. Intraoperatively, 98% of patients were stone free on fluoroscopy, which was 76% on day 1 post op ultrasound and 83% on CT at 1 month. Stone free was the absence of detectable calculi. CONCLUSIONS: UMP for 10-20mm stones appears to be effective and safe with few complications and a short length of stay. Further multicentre studies are required but if confirmed, UMP may be a valuable addition to the armamentarium of the endourologist.
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OBJECTIVE: To introduce an emerging technique termed ‘super-mini- percutaneous nephrolithotomy’ (SMP) and describe its application in practice. METHODS: We described the technique of SMP in the treatment of renal stones with emphasis on the material, indications, technique procedure, advantages, and results. RESULTS: SMP refers to a 7 Ch. nephroscope placed through a 10-14 Ch. metal access sheath with functions of both irrigation and suction-evacuation, to achieve stone fragmentation via laser or pneumatic lithotripsy. We reported our experience of this technique in 342 cases including 231 adults and 111 children. The mean stone size was 2.3 ± 0.9 cm resulted in 54.3 ± 27.7 min of mean operative time in adults, as well as 39.4 ± 26.2 min for stone size of 1.4 ± 0.5cm in children. In parallel, the initial stone-free rate (SFR) was 89.2% and 90.0% followed with a 94.4% and 95.5% of final SFR at 3 months in adults and children, respectively. No transfusions were needed in all patients. Tubeless was achieved in 93.9% and 100% of patients in adults and children respectively. The mean hospital stay was 2.3 ± 0.8 d and 2.7 ± 1.5 d respectively.CONCLUSIONS: SMP are suited for stones less than 2.5 cm in size. It is also suited for special situations such as pediatric moderate-sized stones, previously failed SWL or RIRS approaches. It has advantages of a shorter operative time and hospital stays, with a largely reduction use of drainage catheter after procedure. The indications of the SMP may also compete with those of SWL and RIRS.
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Miniaturization in percutaneous surgeryhas seen its zenith in microperc. Technological advanceshave enabled us to treat renal lithiasis through a4.8 Ch. caliper percutaneous access. According topublished literature, the technique is reproducible andwhen applied to small and medium size renal lithiasishas a high success rate keepin a low complication rate.Its main advantage is the absence of tract dilatation,diminishing the bleeding risk inherent to percutaneousaccess, postoperative pain and hospital stay. Nevertheless,it presents a series of technical limitations: lowmaneuverability and versatility, impossible extraction ofsignificant fragments, limited vision and high intrarenalpressure. Does microperc have a place among proventechniques such as SWL, flexible ureteroscopy or minipercutaneoussurgery? In our article we try to answerthis question by reviewing the available literature, andreview all technical features, advantages and limitationsof the procedure at the same time.
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Miniaturized percutaneous nephrolithotomy(mini-PCNL) has increased in popularity in recentyears and is now widely used to overcome the therapeuticgap between conventional PCNL and less-invasiveprocedures such as shock wave lithotripsy (SWL) orflexible ureterorenoscopy (URS) for the treatment of renalstones. However, despite its minimally invasive nature,the superiority in terms of safety, as well as the similarefficacy of mini-PCNL compared to conventional procedures,is still under debate. The aim of this chapter is topresent one of the most recent advancements in termsof mini-PCNL: the Karl Storz “minimally invasive PCNL” (MIP). A literature search for original and review articleseither published or e-published up to December 2016was performed using Google and the PubMed database.Keywords included: minimally invasive PCNL; MIP.The retrieved articles were gathered and examined. Thecomplete MIP set is composed of different sized rigidmetallic fiber-optic nephroscopes and different sized metallicoperating sheaths, according to which the MIP iscategorized into extra-small (XS), small (S), medium (M)and large (L).Dilation can be performed either in one-step or with aprogressive technique, as needed. The reusable devicesof the MIP and vacuum cleaner efect make PCNL withthis set a cheap procedure. The possibility to shift froma small to a larger instrument within the same set (Matrioskatechnique) makes MIP a very versatile techniquesuitable for the treatment of almost any stone. Studies inthe literature have shown that MIP is equally effective,with comparable rates of post-operative complications,as conventional PCNL, independently from stone size.MIP does not represent a new technique, but rather acombination of the last ten years of PCNL improvementsin a single system that can transversally cover all availabletechniques in the panorama of percutaneous stonetreatment.
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Over the last 30 years, the treatment of urinary lithiasis has changed dramatically. With the advent of extracorporeal lithotripsy and the advances on ureterorenoscopy and percutaneous nephrolithotomy, the need to turn to open and laparoscopic/robotic surgery has diminished. The objective of this article is to review the different indications for open and/or laparoscopic treatment of urinary lithiasis, to achieve its complete elimination with the less invasive possible means and trying to minimize the number of secondary procedures as well as complications.
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OBJECTIVE: To address various issues concerning the fate of residual fragments (and the patients carrying them), their detection, and current and future techniques to avoid them. METHODS: Narrative overview of the all relevant articles retrieved from Pubmed research together with the experiences of personal practice was conducted. RESULTS: Clinically insignificant residual fragments (CIRFs) are defined as asymptomatic, non-obstructing residual fragments smaller than 4 mm (1.6-8) or 5 mm. CIRFs can be diagnosed with either direct endoscopic vision or using imaging modalities including ultrasonography and computerized tomography. Although ultrasonography is radiation-free, the sensitivity and specificity is relatively low when compared to non-contrast computerized tomography. CONCLUSION: The best and the easiest way to deal with residual fragments is preventing their occurrence. Although asymptomatic residual fragments can be safely followed up, symptomatic fragments should be promptly treated. Several modifications and modalities are currently available to treat the fragments occurring after different treatment options.
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Renal lithiasis is known for its high incidence and prevalence, but mainly for its morbidity and recurrence. Despite a good indication and appropriate surgical treatment, the essential problem, the origin of the formation of the stones, generally persists and it is not uncommon that patients suffer multiple treatments and discomfort secondary to ancillary measures normally used to prevent complications. It is widely known, for consistency, that a prophylactic treatment with general or, in a smaller group of patients, specific measures are appropriate to diminish recurrences. Nevertheless, prophylaxis is not usually used by many urologists and, on top of that, in the majority of those cases when it is taken into consideration, it is the patient who fails for inadequate treatment compliance. It is very important, in any of our conversations with the urinary lithiasis´ patient in relation with the disease, that the urologist provides a proper and detailed information about all its features, from diagnosis to active treatment and possible complications and, of course in those cases where prophylaxis is going to be essential to avoid new unpleasant episodes of pain and associated surgical interventions, emphasizing that improving his/her quality of life depends, to a great extent, on the patient himself. In this article, considering the existing evidence and personal experience, we intend to detail those behaviors we should take into consideration to facilitate the patient both therapeutic decisions and a positive attitude towards his/her disease, with the aim to control it in the best possible way.
