Blaschko, Sarah D

Breyer, Benjamin N

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UCSFUC San Francisco Previously Published WorksTitleLettersPermalinkhttps://escholarship.org/uc/item/831813vkJournalBJU International, 112(4)ISSN1464-4096AuthorsBlaschko, Sarah DBreyer, Benjamin NPublication Date2013-08-01DOI10.1111/bju.12362_4 Peer reviewedeScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaLettersAre there long-term effects of extracorporealshockwave lithotripsy in paediatric patients?Sir,The authors have described very well the long-termconsequences of extracorporeal shockwave lithotripsy(ESWL) in children and concluded that there was no effectof ESWL on renal growth or development of hypertensionor diabetes mellitus later in life [1].Although, not USA Food and Drug Administrationapproved, ESWL is a commonly used treatment option forpaediatric stone disease [2]. The long-term bio-effects ofESWL are still considered controversial, especially in thepaediatric population.Various studies have been conducted in this regard, but thedilemma persists as to whether ESWL given in the earlydecades of life is harmful as regards the later developmentof hypertension, diabetes mellitus or impact on renalgrowth. These issues are of concern as several animalstudies have proved the potential for adverse long-termconsequences of ESWL in the paediatric population in theform of a significant decrease in effective renal plasma flowor a significant increase in mean arterial blood pressure [3].These animal studies suggest that the acute renal injurymay progress to scar formation resulting in loss offunctional renal volume. Also in a 9-year follow-up study ofchildren, overall renal size was found to be decreased notonly in the treated kidney after a session of ESWL, but alsoin the contralateral normal kidney [4].There is ample published evidence that suggests thedevelopment of new onset of diastolic hypertension inadults long after lithotripsy and the paediatric kidney ismore susceptible to injury as compared with adults [5].Nevertheless, there is the utmost need for further researchwith longer follow-up durations on the mechanism andconsequences of shockwave renal injury, especially inyoung populations.Manish Garg, Apul Goel and Arvind KumarDepartment of Urology, King George Medical University,Lucknow, IndiaReferences1 El-Nahas AR, Awad BA, El-Assmy AM et al. Are therelong-term effects of extracorporeal shockwavelithotripsy in paediatric patients? BJU Int 2013; 111:666–712 Krambeck AE, Lingeman JE. Clinical implications andbioeffects of shock wave lithotripsy. AUA Update Series2009: 283 Neal DE Jr, Harmon E, Hlavinka T, Morvant A,Richardson E, Thomas R. Effects of multiplesequential extracorporeal shock wave treatments onrenal function: a primate model. J Endourol 1991; 5:217–214 Lifshitz DA, Lingeman JE, Zafar FS, Hollensbe DW,Nyhuis AW, Evan AP. Alterations in predicted growthrates of pediatric kidneys treated with extracorporealshockwave lithotripsy. J Endourol 1998; 12: 469–755 Janetschek G, Frauscher F, Knapp R, Höfle G, PeschelR, Bartsch G. New onset hypertension afterextracorporeal shock wave lithotripsy: age relatedincidence and prediction by intrarenal resistive index.J Urol 1997; 158: 346–51ReplySir,Extracorporeal shockwave lithotripsy (SWL) is the mostcommonly used treatment for non-complex urinary calculiin adults. In pediatric patients, there were concerns aboutthe possible harmful effects of ESWL on the parenchyma ofgrowing kidneys. These concerns were assessed in animalmodels. Kaji et al. [1] reported histological changes in renaltubular and glomerular epithelium and interstitial cells inimmature rabbits after SWL. These changes were thoughtto be the cause of an increase in arterial blood pressureamong tested rabbits. However, SWL in that study wasdelivered directly to the renal parenchyma, which isdifferent from clinical practice where SWL is delivered tothe stones. Moreover, Kaji et al. [1] noticed no significantreduction in renal function or renal growth after SWL inimmature rabbits.On the other hand, clinical studies have proved that thereare no significant long-term harmful effects of SWL onpediatric kidneys [2–3] and SWL did not statistically affectlinear growth (body height) or renal function in thepediatric population [4].The concerns about the development of systemic diseases,e.g. hypertension and diabetes, were studied in adults withcontradictory results. In pediatric patients, Lottmann et al.[2] and Frick et al. [3] found that SWL was not associated© 2013 The AuthorE424 BJU International © 2013 BJU International | 112, E424–E428 | doi:10.1111/bju.12362with increased incidence of hypertension. Our studyproved the long-term safety of SWL for renal stones duringchildhood because there were no harmful effects on renalgrowth, linear growth or development of hypertension ordiabetes [5].The lesson learnt from these studies is that safe applicationof SWL in children requires adequate targeting, lowenergies and a limited number of shocks per session forsparing the renal parenchyma any possible deleteriouseffects [2]. Although SWL was considered to be the methodof choice for managing renal stones in children of all ages[6], more studies with long-term follow-up are required toconfirm the safety of SWL in pediatric patients.Ahmed R. EL-NahasOn behalf of the authorsReferences1 Kaji DM, Xie HW, Hardy BE, Sherrod A, Huffman JL.The effects of extracorporeal shock wave lithotripsy onrenal growth, function and arterial blood pressure in ananimal model. J Urol 1991; 146: 544–72 Lottmann HB, Archambaud F, Traxer O,Mercier-Pageyral B, Hellal B. The efficacy andparenchymal consequences of extracorporeal shockwave lithotripsy in infants. BJU Int 2000; 85: 311–53 Frick J, Sarica K, Köhle R, Kunit G. Long-termfollow-up after extracorporeal shock wave lithotripsy inchildren. Eur Urol 1991; 19: 225–94 Thomas R, Frentz JM, Harmon E, Frentz GD. Effectof extracorporeal shock wave lithotripsy on renalfunction and body height in pediatric patients. J Urol1992; 148: 1064–65 El-Nahas AR, Awad BA, El-Assmy AM et al. Are therelong-term effects of extracorporeal shockwavelithotripsy in paediatric patients? BJU Int 2013; 111:666–716 D’Addessi A, Bongiovanni L, Sasso F, Gulino G,Falabella R, Bassi P. Extracorporeal shockwavelithotripsy in pediatrics. J Endourol 2008; 22: 1–12De novo erectile dysfunction after anteriorurethroplasty: a systematic review andmeta-analysisSir,We read this article [1] with interest regarding theincidence of de novo erectile dysfunction (ED) afteranterior urethroplasty. The authors have tried to clear the‘grey areas’ in anterior urethroplasty and ED. However, theauthors need to address some issues. We would like toknow the basis by which the authors calculated theincidence of ED, as no clear cut universal definition for EDwas followed in the different studies. Of a total 36 studies,preoperative data about ED was only available in fivestudies [457 patients (ª20%) out of the total 2323], so howdid the authors calculate that some patients developed denovo ED, as their preoperative status was unknown. It alsoneeds to be clarified at what time after surgery erectilefunction was assessed and how the authors concluded thatthere was a 1% incidence of ED. Moreover, the totalnumber of patients with ED was 165, which is 7.1 % of thetotal 2323 patients.Apul Goel, Kuldeep Sharma and Pradeep SharmaDepartment of Urology, King George Medical University,Lucknow, IndiaReference1 Blaschko SD, Sanford MT, Cinman NM, McAninchJW, Breyer BN. De novo erectile dysfunction afteranterior urethroplasty: a systematic review andmeta-analysis. BJU Int 2013 [Epub ahead of print]DOI: 10.1111/j.1464-410X.2012.11741ReplySir,We appreciate the opportunity to provide additionalinformation about our article [1]. The questions you raisepoint out some limitations of meta-analysis in general. Inthis study, meta-analysis involves comparing studies withheterogeneous definitions of erectile dysfunction (ED) andvariation in follow-up duration across studies.The definition for ED differed across studies and rangedfrom new reports of ED postoperatively to a decline inInternational Index of Erectile Function (IIEF) score.Whether or not ED was self-reported, if all patients werequestioned about ED, or if a standardised questionnaire toevaluate ED was used, is described for each study inTable 1. In retrospective studies where patients were notasked about erectile function in advance, new onset EDafter urethroplasty is self-reported and is subject to recallbias. In meta-analysis, the most weight was given to studiesthat prospectively questioned all patients about ED with astandardised questionnaire.The time frame by which ED was determined was notprovided in the methods for all studies included in ourmeta-analysis. The prospective studies that evaluated EDtypically used a time frame of 6–18 months to evaluatepostoperative erectile function. The study follow-up timeframe is listed in Table 1.Letters© 2013 The AuthorsBJU International © 2013 BJU International E425Random effects meta-analysis was used to calculate theincidence of ED rather than simply dividing the number ofcases of ED by the total number of patients [2].Sarah D. Blaschko and Benjamin N. BreyerOn behalf of the authorsReferences1 Blaschko SD, Sanford MT, Cinman NM, McAninchJW, Breyer BN. De novo erectile dysfunction afteranterior urethroplasty: a systematic review andmeta-analysis. BJU Int 2013 [Epub ahaead of print].DOI: 10.1111/j.1464-410X.2012.117412 Kontopantelis E, Reeves D. metaan: random effectsmeta-analysis. STATA Journal 2010; 10: 395–407Newer and novel artificial urinary sphincters(AUS): the development of alternatives to thecurrent AUS deviceSir,Despite the growing emergence of mini-invasive surgicaltreatments for urinary incontinence (i.e., urethral slings,injections of bulking agents, adjustable continence therapies,and stem cell therapies), the AMS 800® artificial urinarysphincter (AUS) (American Medical Systems, Minnetonka,MN, USA) has remained the ‘gold standard’ treatment forstress urinary incontinence in men and women over the last40 years. Despite the favourable outcome and satisfactionrates after its implantation, this device continues to beassociated with the risk of local complications (i.e., atrophy,erosion and infection) or mechanical failure. Thus, regularrevisions and/or explantations are mandatory in at least 30%of AUS devices. New and more sophisticated AUS deviceshave recently been developed to improve function,occlusive efficiency, and biocompatibility relative to itscurrent design.In a recent article, Chung et al. [1] provided a review ofnew and/or innovative AUS devices.The FlowSecure AUS (FlowSecureTM, RBM-Med) wasdesigned in 1991 with early functional outcomes reportedin 2006. It has the main advantage of instantly increasingthe pressure delivered to the urethra, only during stressincreases in intra-abdominal pressure. When deactivated,the cuff returns to the initial low pressure level, neverexceeding 40 cmH2O, thus minimising the risk of urethralatrophy and/or erosion. As indicated by Chung et al.[1], despite encouraging preliminary results with theFlowSecureTM, more recent data have shown highmechanical failure and infection rates, as well as risk ofpump assembly perforation in short- to intermediate-termfollow-up.The Periurethral Constrictor (Silimed, Rio de Janeiro,Brazil) was released in 1996. It is simple to use and oflow cost. However, there are only a few publishedstudies with controversial outcomes for the device in apost-prostatectomy urinary incontinence setting [2]. Theroutine use of this device is debatable.The Tape Mechanical Occlusive Device (GT UrologicalLLC, Minneapolis, MN, USA) is a non-hydraulic one-piecedevice that is manually controlled by the patient through itson/off buttons [3]. It has been implanted in dogs to assessits function, occlusive efficiency, and biocompatibility andin human male cadavers to assess its occlusive efficiencyand sizing, with encouraging results. Prospective clinicalstudies are awaited.Two additional devices have been developed in France. TheZSI 375 (Zephyr Surgical Implants, France) was released in2005 (http://zephyr-si.com/zephyr/index.php?lg=en.) andhas not yet been approved by the French Health AuthorityAgency (http://www.has-sante.fr/portail/jcms/c_896387/zsi-375-cnedimts-du-24-novembre-2009-2254) despitepublication of recent data. No strong basic (bench andanimal) and/or clinical data are available, and the use ofthis device should be done under a prospective controlledstudy before extensive use. Indeed, only a few preliminarymonocentric retrospective observational studies have beenreported. There are no favourable comparisons with theAMS 800®, and as opposed to the two following devices, theVersatile Automated Device and electromechanical device,it has not followed, at least through published papers, theusual process of validation.Chung et al. [1] have not mentioned the VersatileAutomated Device recently designed by another Frenchteam [4], designed to obtain a lower exerted pressure onthe urethral tissues and improve continence efficiencyaccording to the patient’s activity. In fact, this deviceincludes a sensor, which automatically detectscircumstances involving high bladder pressure and adaptsthe occlusive pressure accordingly. The device wasevaluated using isolated goat urethra and, then, in vivo withencouraging preliminary results. Research studies (benchand animal) are still running and awaited.An electromechanical device has also been developed byValerio et al. [5] and recently tested in animals. Its principleis an electromechanical induction of alternatingcompression of successive segments of the urethra by aseries of cuffs activated by artificial muscles. This ovinestudy showed that this device could provide continence.This new electronic-controlled sequential alternatingcompression mechanism avoided damage to urethralLetters© 2013 The AuthorsE426 BJU International © 2013 BJU Internationalvascularity for at least 3 months after implantation. Afterthis positive early step, long-term studies are needed beforeclinical application can be considered. Table 1 shows theinnovative principles of each former model of the AUS.In conclusion, in an era where AUS use is increasing, a newand more sophisticated device is probably needed.Whatever the use, in men or women, the AUS aims tomimic continence/voiding phases as close as possibleto normal conditions. Nobody knows what the futureholds for hydraulic and mechanical devices. Theabove-mentioned devices suggest that further studies arerequired to assess the safety and efficacy of these newgeneration AUS devices, in comparison with the so-called‘gold standard’ AMS 800®. The developmental steps forthese devices must include bench and animal studies, aswell as feasibility studies in humans to control for safetyand surgical efficiency. Figure 1 provides the main steps ofdevelopment of medical devices. After a feasibility study tocheck the proof of concept, any clinical use must bepreceded by multicentre controlled studies. All of thesestudies have to be done under ethical committee approval.The recent USA Food and Drug Administration (FDA)warning (http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/ImplantsandProsthetics/UroGynSurgicalMesh/ucm262299.htm) about prolapseTable 1 Innovative characteristics of AUS compared with the current AMS 800®.Device More compactthan theAMS 800®Improved controlof pressureduring stressImproved detectionof the administeredpressureAdjustable Key remainingquestionsFlowSecure™ No Yes No Yes Pump perforation atpressurisationPeriurethral Constrictor Yes No Yes Yes Controversial results oncontinenceTape Mechanical OcclusiveDeviceYes No No No but simplicity of usewith its on/off button?ZSI 375 Yes No No Yes No multicentre prospectivecontrolled studyVersatile Automated Device Yes Yes Yes Yes ?Electromechanical Device ? Yes Yes No ?Fig. 1 Key steps for the clinical development of a medical device.Preclinical phase  Clinical phase Provision of themedical device Research & developmentto address the clinicalneed  In vitro tests(biocompatibility tests) +/- Animal experimentsPilot study Safety +++ (complication)Selection of patients & surgical techniquePivot StudyMain objective with Primaryendpoint Criteria of inclusion/exclusionChoice of control treatment incase of comparative study Experimental planeChoice of investigating centres(multicentre study)Letters© 2013 The AuthorsBJU International © 2013 BJU International E427meshes in women should warn all clinical research teamsabout the absolute need for careful evaluation for all newimplantable human devices.Véronique Phé, Morgan Rouprêt andEmmanuel Chartier-KastlerAP-HP, Pitié-Salpêtrière Academic Hospital, Department ofUrology, Pierre et Marie Curie medical school, Paris 6University, Paris FranceReferences1 Chung E, Ranaweera M, Cartmill R. Newer and novelartificial urinary sphincters (AUS): the development ofalternatives to the current AUS device. BJU Int 2012;110: 5–112 Schiavini JL, Damião R, de Resende Júnior JA,Dornas MC, Cruz Lima da Costa DS, Barros CB.Treatment of post-prostate surgery urinaryincontinence with the periurethral constrictor: aretrospective analysis. Urology 2010; 75: 1488–923 Malaeb BS, Elliott SP, Lee J, Anderson DW, TimmGW. Novel Artificial Urinary Sphincter in the CanineModel: The Tape Mechanical Occlusive Device. Urology2011; 77: 211–64 Lamraoui H, Bonvilain A, Robain G et al.Development of a novel artificial urinary sphincter: aversatile automated device. IEEE/ASME Transactions onMechatronics 2010; 15: 916–245 Valerio M, Jichlinski P, Dahlem R, Tozzi P, MundyAR. Experimental evaluation of an electromechanicalartificial urinary sphincter in an animal model. BJU Int2013; 112: E337–43Letters© 2013 The AuthorsE428 BJU International © 2013 BJU International

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