Is One-Stage Ureterocele Repair Possible in Children? $

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1 European Urology European Urology 42 (2002) 607±613 Is One-Stage Ureterocele Repair Possible in Children? $ Paul Sauvage *, FrancËois Becmeur, RaphaeÈl Moog, Isabelle Kauffmann Service de Chirurgie Infantile, CHU Hautepierre, Strasbourg, France Accepted 30 April 2002 Abstract Aim: To determine the long-term results of ureterocele repair, bearing in mind the relative rarity of the malformation, its very polymorphic appearance and the diversity of treatments. Materials and Methods: Long-term results were assessed by postoperative follow-up of 126 children with 131 ureteroceles between 1970±2000. Results: With a mean follow-up of 72 months, only 64.2% of children were cured after a one-stage procedure. According to the anatomical type, favourable results were obtained in 81.6% of cases with a single ureter and 57.9% of cases with a duplicated ureter. Treatment success rates for single or duplicated ureters were 73% in the case of intravesical implantation and only 53.9% (34/63 children) in ectopic forms. According to the technique, cure rates were 67.6% after distal incision in 34 children, 61.9% after total nephrectomy or upper pole nephrectomy in 42 children, 50% after ureterocele repair and ureterovesical reimplantation in 20 patients, 75% after total resection of the pathological ureter, parietal reconstruction and ipsilateral and/or contralateral reimplantation in another 20 patients. Conclusions: A one-stage procedure is only able to cure 2/3 of patients. In view of the tendency to progressive regression of often monstrous distensions during the neonatal period, rst-line treatment should consist of a distal incision, followed, in the case of recurrent infections, by partial or total nephrectomy, while reserving the intravesical approach to cases with recurrent pyelonephritis. When this surgery is performed on older children or adolescents, the ureteroceles will be smaller with a lower risk of sphincter damage. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Ureterocele; Uropathy; Treatments; Results; Neonate; Child 1. Introduction Ureterocele is an abnormal dilatation of the terminal portion of a single ureter or, more frequently, the upperpole ureter of a duplicated ureter with ectopic or normal implantation. The site and dimensions of the vesical or vesicourethral implantation of the ureterocele determine the abnormalities of anastomosis of the homologous and contralateral tracts responsible for dilatation and/or massive re ux. The degree of urinary tract distension appears to be totally independent of the functional capacities of the corresponding kidney or renal segment and the presence or absence of renal dysgenesis. $ French version of this paper is published in ProgreÁs en Urologie 2002;12:443±9. * Corresponding author. Tel ; Fax: address: paul.sauvage@chru-strasbourg.fr (P. Sauvage). A large range of treatment options have been proposed in view of the extreme variety of urological lesions observed. Total or partial resections have been replaced by minimally invasive surgery, and more conservative endoscopic procedures, often modulated according to the type of lesion, the child's age and general state at the time of the diagnosis and current practices. Although the principles of treatment remain simple: more or less complete resection of the pathological urinary tract, treatment of re ux, possibly associated with resection of the ureterocele, conservative surgery or watchful waiting, the practical modalities and operative timing appear to be very variable and need to be more clearly de ned and validated. The treatment and long-term follow-up of this highly polymorphous uropathy by or under the supervision of the same surgeon has led to the question: can /02/$ ± see front matter # 2002 Elsevier Science B.V. All rights reserved. PII: S (02)

2 608 P. Sauvage et al. / European Urology 42 (2002) 607±613 ureteroceles in children be cured by a one-stage procedure and according to which technique? 2. Material and methods Over the last 30 years (1970±2000), 126 children (80 girls and 46 boys) with a mean age of 23 months (range: 1±164 months), presenting a total of 131 ureteroceles, including 5 bilateral ureteroceles, were reviewed with a mean follow-up of 72 months (range: 1±270 months). A nephrological, infectious, and urological assessment, comprising intravenous urography and/or renal ultrasound, retrograde cystography, and DMSA renal scan is essential before taking any treatment decision. Neonates and infants are managed in close collaboration with paediatric nephrology teams Diagnostic conditions The diagnosis was established antenatally in 48 children (38%) and in a context of urinary tract infections in 44 cases, assessment for abdominal pain, abdominal mass, apparent malformations in 15 cases, prolapse of the ureterocele in 7 cases, macroscopic haematuria in 5 cases, voiding disorders in 3 cases, acute renal failure in 2 cases and purulent discharge in 2 cases Initial assessment The urinary tract was duplicated in 88 patients (68 girls, 20 boys) and single in 38 patients (26 boys and 12 girls). The implantation was ectopic in 63 cases (49 girls, 14 boys) and intravesical orthotopic in the other 63 children (32 boys and 31 girls). The kidneys or upper renal segments associated with the ureterocele were silent (74), dilated with decreased function (36), or normal (15). Ipsilateral renal function was normal in only 15 out of 126 cases, but global renal function was normal in 123 out of 126 cases (97.6%). Only one child with a cloacal malformation presented renal failure since birth. Cystography detected 59 re uxing ureters in 47 patients (37.3%), classi ed as follows: stage I: 5, stage II: 17, stage III: 13, stage IV: 17, and stage V: 7; ipsilateral in 46 cases (upper pole: 5, middle and lower pole: 41) and contralateral in 13 cases. Eighty-one children were operated during the rst year of life and more than half were operated during the rst months of life. One hundred and sixteen patients were able to be classi ed into coherent groups. A speci c surgical procedure was performed in 6 children: simple aspiration of the prolapsed ureterocele (3), ureteropelvic (2) or uretero-ureteric (1) anastomosis with or without ureterectomy, three other patients are under surveillance in the absence of any clinical disorders (2) or following parental refusal of treatment (1). 3. Results 3.1. Conservative surgery:34 children/36 ureteroceles In the 20 cases of ureterocele in a single urinary tract, including 2 bilateral cases, the ureteroceles were orthotopic with no associated re ux, and the kidneys were functioning but dilated (15), silent on IVU (1) or normal (2). The 16 cases of ureterocele on a duplicated tract, including 9 ectopic ureters, were associated with middle and lower pole re ux in three cases, graded from grade 1±5 (bilateral), eight renal segments were functioning, but dilated, ve were silent on IVU and three were normal. Mean age at the time of the operation: 24 months, range: 1±164 months. Mean follow-up: 53 months, range: 2±188 months. Distal incision using a resector, hook, urethrotome or open resection-suture or endoscopic enlargement of the stenotic meatus of the ureterocele by Cook 3.7 or 5 F probe achieved cure with no other treatment in 23 children (67.6%). Although 18 children with 20 ureteroceles on single ureters were cured immediately (90%), the success rate was only 50% for duplicated ureters (8 out of 16). Eleven children developed complications: recurrent pyelonephritis due to re ux (9), secondary prolapse of the ureterocele (1) and epididymitis (1). The severity and persistence of these disorders led to 14 reoperations: once (9 cases), twice (1 case) and three times (1 case) Resections:82 children Resection was either exclusively partial and extravesical or total and intravesical, removing all of the pathological urinary tract via a double incision Extravesical approach:total or upper pole ureteronephrectomy:42 children All total (11) and partial (31) nephrectomies were performed on silent kidneys on IVU with no uptake on DMSA scan, except for two severely dilated small upper poles with low uptake. Mean age at operation: 15 months, range: 1±121 months. Mean follow-up: 79 months, range: 2±192 months. Cure was obtained with no other treatment in 27 patients (64.2%), nephrectomy: 8/11 (72.7%), partial nephrectomies: 19/31 (61.2%). Complications were observed in 15 patients: recurrent pyelonephritis (9), recurrent lower urinary tract infections usually associated with purulent discharge (3), recurrent epididymitis (1), persistent distension of the ureterocele (1), and deterioration of hydronephrosis (1). Twenty- ve reoperations had to be performed: once (7 cases), twice (6 cases) and three times (2 cases) Intravesical approach:ureterocele repair and ureterovesical reimplantation:21 children Seventeen duplicated ureters, including 7 orthotopic ureters with a normal (3), dilated (4), or silent (1) upper pole and 10 ectopic ureteroceles with a functioning

3 P. Sauvage et al. / European Urology 42 (2002) 607± renal segment (5), silent (2), dilated (2), or atrophied (1) upper pole. Four single ureters with orthotopic ureteroceles and dilated kidneys (2), or ectopic ureteroceles and silent kidneys (2) were treated by contralateral reimplantation. Mean age at operation: 46 months, range: 4±119 months. Mean follow-up: 62 months, range: 3±239 months. Cure with no other treatment: 10 children (47.6%): 3 with single ureters (75%), 7 with duplicated ureters (41.7%). Eleven children developed complications: recurrent re ux with pyelonephritis (9), renal failure (1), and stones (1) requiring 16 reoperations: once (8 cases), twice (1 case) and three times (2 cases) Double lumbar and transvesical approach: complete resection of the urinary tract with reconstruction of the bladder oor and ipsilateral and/or contralateral ureterovesical reimplantation: 19 children All but two of the kidneys and renal segments were silent on IVU and DMSA scan. The four single ureters were ectopic, and the duplicated ureters were essentially ectopic (12 cases) and orthotopic in only 3 cases. Mean age at operation: 19 months, range: 1±130 months. Mean follow-up: 127 months, range: 1±270 months. Cure with no other treatment: 13 children (68.4%). Four ectopic single ureters (100%) and 9 duplicated ureters: 6 ectopic (75%) and 2 orthotopic (66.6%). Six patients developed complications: recurrent re ux with pyelonephritis (5), urinary retention and dilatation of a single functioning kidney. All of these children were successfully treated by a single reoperation. Sequelae persisted in 4 children: atrophy of the middle and lower renal segments after upper pole nephrectomy (3) and incontinence (1) Various techniques:7 Cure: ve children. Three children were treated by ureteropelvic (2) or uretero-ureteric (1) reimplantation with functional exclusion of the terminal part of the urinary tract because of a good functioning upper pole (3 successes). Simple aspiration was performed in 3 cases (1 success on a small dysplastic renal segment). Successful removal of incrusted stones in an ectopic ureterocele in a 10-year-old boy (1) Surveillance and refusal of treatment: 3 children Two young boys were simply followed. One boy with an antenatal diagnosis of renal dysplasia was treated by resection of this formation because of prolapse of the ureterocele into the bladder neck and the other boy presented non-complicated bilateral orthotopic single ureteroceles discovered during systematic assessment of post-maturity. The parents of a young girl, now 11 years old, with an antenatal diagnosis, accepted certain investigations but refused treatment. This case con rmed the progressive regression of the distension, but also the persistence of urinary tract infections and deterioration of the ipsilateral renal function. In our experience, no emergency procedure was necessary in patients under surveillance or in children with undetected ureteroceles Overall results Only 64.2% (79/123) of children were cured after a single operation: 46 girls (57.2%) and 33 boys (71.7%). Results according to anatomical type: favourable results were obtained in 81.6% of cases of single ureters and 57.9% of cases of duplicated ureters. The success rates for single or duplicated ureters were 73% in the case of intravesical implantation and only 53.9% (34/63 children) in the case of extravesical implantation. The study of nephrectomy specimens revealed 38.5% of nephritic and pyelonephritic kidneys in the case of one-stage cure versus 28% in the case of reoperation and dysplastic kidneys in 46% and 53.5% of cases, respectively. The renal function at last follow-up was pathological in 120/126 of ipsilateral renal segments, but global renal function remained normal in 107 out of 126 patients (84.9%). 4. Discussion In the age of minimally invasive and one-stage surgery, and the rapid publication of results, how can we explain these high reoperation rates? Our overall results are corroborated by those of Decter et al. [7] who reported a 75% cure rate in a series of 38 children followed over the last 10 years We will try to answer these questions by a review of the literature and in the light of our own experience Relative rarity of the malformation and limited individual experience Antenatal diagnosis, early infectious complications and demonstration of marked dilatation of the urinary tract can lead to a hasty decision to perform useless or inappropriate and often dangerous major surgical procedures.

4 610 P. Sauvage et al. / European Urology 42 (2002) 607±613 Fig. 1. Extreme diversity of ureteroceles. Constant reduction of the thickness of the bladder wall and bladder neck due to development of an ectopic ureterocele Extreme diversity of the malformations The severity of ureteroceles, either unilateral or bilateral, affecting single ureters or duplicated ureters, is essentially related to their ectopic bladder neck implantations, which can constitute a challenge to even the most experienced surgeon when surgical resection is attempted. The large implantation base of certain forms on non-functioning single ureters may be masked by dilatation of the posterior urethra and by an enormous bladder diverticulum because of the ne detrusor and distension of the bladder neck (Fig. 1) Histology of nephrectomy specimens The study of 68 upper pole or total nephrectomy specimens revealed a pathological kidney in 56 cases (82.4%), with 36 dysplastic kidneys (presence of cartilaginous tissue: 12, calci cations: 4), 20 cases of infectious sequelae (interstitial nephritis: 10, pyelonephritis: 10, chronic in 6 cases and acute in 4 cases). Seven kidneys presented tubular distensions and were described as hydronephrotic and ve were considered to be normal, always corresponding to partial nephrectomies. One-stage cure was essentially related to elimination of infectious lesions rather than to resection of dysplastic structures. According to Abel et al. [1], dysplasia is observed in 70% of ureteroceles and only 30% of ectopic ureters in a series of 50 histological specimens Time to reoperation Although most infectious complications, related to persistence or recurrence of re ux or disease of the remaining kidney or renal segments, occur very early, our experience shows that adolescent girls may suffer from recurrent lower urinary tract infections associated with purulent discharge, following their rst sexual relations, after a symptom-free period of more than 10 years, or even 15 years. The discovery of often large ureteric stumps and especially ureteroceles left in place because of their initial large dimensions requires their resection under easier conditions, but always with the risk of inducing incontinence in a previously continent adult (Fig. 2) Techniques and their results Simple aspiration This technique can only be effective on prolapse with dysplastic kidney Distal enlargement of the meatus This procedure facilitates decompression of the upper urinary tract, but leaves the pathological renal structures and the ureterocele in place. An insuf cient opening with a thick wall requires repeated procedures, while an overlarge opening leads to major re ux and recurrent pyelonephritis. Most authors consider that this technique can only constitute a preliminary procedure before more radical operations, which would then be easier to perform. According to Jayanthi and Koff [10] ``Initial success and late problems'' and Dahm and King [6] ``The delay permits interim growth that is likely to make bladder reconstruction easier''. Haag et al. [9] emphasizes the need for repeated aspiration of thick-walled ureteroceles and reported a 37% reoperation rate in 51 patients with duplicated ureters. Cooper et al. [5], after a preliminary optimistic publication, admitted to a reoperation rate of 18% in 22 intravesical ureteroceles and 64% in 22 ectopic forms. According to Chertin et al. [3], endoscopic treatment avoids the need for a major surgical procedure in most cases, but the mean follow-up was only 6.1 years. Petit et al. [12], based on a series of 18 cases, consider that

5 P. Sauvage et al. / European Urology 42 (2002) 607± Fig. 2. Time of last postoperative follow-up and type of reoperation in years after the initial operation. endoscopic treatment can delay nephrectomy, facilitates intravesical surgery and allows dysplastic renal segments to be left in place with no complications Upper pole or total nephrectomy This procedure appears to be the most satisfactory short-term and medium-term solution. The ureterocele collapses and it can always be resected subsequently in the case of complications. The very high incidence of renal abnormalities tends to encourage renal resection rather than conservative surgery, but Moscovici et al. [11] also reported the need for intravesical revision in 37.5% of a series of 32 cases Ureteropelvic and uretero-ureteric anastomoses associated with segmental ureterectomy These procedures are elegant and effective in the absence of a history of infection and provided good renal function is preserved. According to Choi and Oh [4], who performed 13 primary uretero-ureterostomies in 63 children, this is an ideal treatment, but they also reported a 34% reoperation rate in this series Ipsilateral and/or contralateral ureterovesical reimplantations with resection of the bulging ureter and/or total resection of the ureterocele and bladder neck repair This operation is especially designed to treat obstructive megaureters, and primary or secondary re ux and is an ideal treatment of intravesical ureteroceles on single ureters. However, one disadvantage of this technique is that it leaves pathological renal units in place Total resection of the pathological tract with parietal reconstruction and reimplantation This is by far the most logical approach and achieved cure in 75% of patients in our short series. However,

6 612 P. Sauvage et al. / European Urology 42 (2002) 607±613 one case of stress incontinence and functional loss of three middle and lower renal segments were observed. Although the case of incontinence can be explained by an impressive intrasphincteric development of the ureterocele, to such a point that we had to perform endoscopy to verify the integrity of the vaginal cavity, and although the renal atrophy was probably due to venous thrombosis following reintegration of a renal segment whose vessels had been severely elongated by monstrous renal or ureteric cystic masses, the neonatal procedure appeared to be clearly responsible in each case (frequency of glomeruli still in the process of organogenesis during the rst weeks of life). This atrophy could probably have been avoided by waiting a few months. Shekarriz et al. [13] did not report any reoperation in his series of 18 patients. Thirteen reoperations were performed in the series of 40 patients reported by De Jong et al. [8], who considers that this extensive surgery, performed at a very young age, does not compromise the result with a mean follow-up of 5.59 years Natural history Truly monstrous distensions of the ureterocele and the ipsilateral and contralateral urinary tract have been observed on antenatal examination and in the immediate postnatal period, while ureteroceles detected later in children or adolescents are much more moderate. Ureteroceles may sometimes be asymptomatic, but the infant may present with prolapse of the ureterocele, possible associated with a distended bladder, during the rst hours of life, or recurrent episodes of pyelonephritis during the rst weeks of life. One of our patients only consulted at the age of 5 years because of recurrent lower urinary tract infections and enuresis. On urography, the ureterocele was moderate and the upper tract was not dilated, and no re ux was observed on cystography. An IVU performed at birth because of neonatal infection revealed impressive distension of the urinary tract, but the ureterocele was apparently missed! In another of our cases, prolapse with eversion of the bladder only appeared at the age 18 months in a baby girl who had always been in excellent health. The natural history is marked by regression of the distension, a possibility of prolapse sometimes even aggravated by bladder eversion, a risk of deterioration of renal function due to re ux and urinary tract infection and/or obstruction and stasis Course of morphology and renal function Preoperative assessment of the renal function of the ipsilateral kidney, based on laboratory tests, urography in the older cases, ultrasound and DMSA scan, was considered to be normal in only 15 of our 126 patients. On the other hand, global renal function was considered to be normal in 123 patients (97.6%). At latest follow-up, only 5 ipsilateral kidneys still had normal renal function and global renal function was normal in only 107 of 126 patients (84.9%) Incontinence Incontinence is directly related to the extent of intrasphincteric development of the ureterocele and the degree of surgical aggression. As the natural course is towards reduction of distension, a de nitive procedure should therefore not be performed during the rst months of life. Simple resection of the roof of the ureterocele at adolescence may be suf cient, possibly associated with resection of any ureteric stumps. In any event, the patient and family must be informed preoperatively about the risk of incontinence after any surgical revision. Is it worth the risk to perform large resections associated with colposuspension incontinence surgery, as proposed by De Jong et al. [8] in 16 of his 40 patients? According to Abrahamsson et al. [2], the large bladder capacities and the frequency and severity post-voiding residual urine, in the absence of bladder neck surgery, are an integral part of the disorders related to ureteroceles and not exclusively to surgical complications Therapeutic indications In the light of our experience and a review of the literature, we propose that assessment be deferred until the age of 1 month after ultrasound con rmation of the lesion suspected on the antenatal examination and in the absence of urinary tract infection. In neonates with prolapse and urinary retention, the ureterocele should be collapsed by aspiration or endoscopic section. Partial or total extravesical ureteronephrectomy should be performed in the presence of pyelonephritis. The resulting collapse of the ureterocele often leads to resolution of the associated ipsilateral or contralateral re ux. Although recurrent upper urinary tract infections in a young infant are due to re ux, recurrent upper urinary tract infections in adolescents are essentially due to persistence of ectopic ureteroceles. In every case, the intravesical approach must be cautious, avoiding large resections and reconstructions, as well as preventive colposuspension, which have always appeared to be useless, or even dangerous, for subsequent continence, in our experience.

7 P. Sauvage et al. / European Urology 42 (2002) 607± Conclusion Based on our experience, only 2/3 of ureteroceles in children can be cured by a one-stage procedure. In order to improve these results, in view of the tendency to spontaneous regression of sometimes monstrous distension, watchful waiting should be the rule during the rst few months of life in the absence of infectious complications or impaired renal function. Treatment as minimally invasive as possible and adapted to the anatomical type, the child's age and sex, with surveillance until adulthood, should limit the number of reoperations and ensure satisfactory long-term renal function. References [1] Abel C, Lendon M, Gough DC. Histology of the upper pole in complete urinary duplication, does it affect surgical management. Br J Urol 1997;80(4):663±5. [2] Abrahamsson K, Hansson E, Sillen U, Hermansson G, Hjalmas K. Bladder dysfunction: an integral part of the ectopic ureterocele complex. J Urol 1998;160(4):1468±70. [3] Chertin B, Fridmanns A, Hadas-Halpren I, Farkas A. Endoscopic puncture of ureterocele as a minimally invasive and effective long-term procedure in children. Eur Urol 2001;39(3):332± 6. [4] Choi H, Oh SJ. The management of children with complete ureteric duplication: selective use of uretero-ureterostomy as primary and salvage procedure. BJU Int 2000;86(4):508±12. [5] Cooper CS, Passerini-Glazel G, Hutcheson JC, Iafrate M, Camuffo C, Milani C, Snyder 3rd HM. Long-term followup of endoscopic incision of ureteroceles: intravesical versus extravesical. J Urol 2000;164(3Pt2):1097±9 [discussion ]. [6] Dahm P, King LR. Experience with transurethral incision of ureteroceles. J Urol 1998;61(3):157±61. [7] Decter RM, Sprunger JK, Holland RJ. Can a single individualized procedure resolve all the problematic aspects of the pediatric ureterocele? J Urol 2001;165(6 Pt2):2308±10. [8] De Jong TP, Dik P, Klijn AJ, Uiterwaal CS, van Gool JD. Ectopic ureterocele: results of open surgical therapy in 40 patients. J Urol 2000;164(6):2043±4. [9] Haag MJ, Mourachov PV, Snyder HM, Canning DA, Kennedy WA, Duckett JW. The modern endoscopic approach to ureterocele. J Urol 2000;163(3):940±3. [10] Jayanthi VR, Koff SA. Long-term outcome of transurethral puncture of ectopic ureteroceles: initial success and late problems. J Urol 1999;162(3pt2):1077±80. [11] Moscovici J, Galinier P, Berrogain N, Juricic M. La prise en charge des ureâteroceleás sur dupliciteâ pyeâlo-ureâteârale chez l'enfant aá propos de 64 cas. Annales d'urologie 1999;33(5):369±76. [12] Petit T, Ravasse P, Delmas P. Does the endoscopic incision of ureteroceles reduces the indications for partial nephrectomy? BJU Int 1999;83(6):675±8. [13] Shekarriz B, Upadhyay J, Fleming P, Gonzalez R, Barthold JS. Longterm outcome based on initial surgical approach to ureterocele. J Urol 1999;162(3Pt2):1072±6. Editorial Comment Jacques Biserte, Department of Urology, HoÃpital Huriez, Lille, France Based on my own experience, I know that it is extremely dif cult to clearly present the various types of management of ureteroceles in children: intravesical or extravesical ureterocele, single or duplicated urinary tract, functioning or non-functioning upper pole, associated re ux in the lower pole in the case of duplicated ureter, contralateral re ux, etc. The various possible combinations of all of these criteria illustrate the diversity and complexity of ureteroceles. It is therefore also extremely dif cult to classify the various treatments performed, with a risk of presenting an apparently clear, but actually misleading description of the various therapeutic indications for ureterocele. However, the author has succeeded in emphasizing a number of key points which are obviously based on his extensive experience in this eld. Moreover, some of these key points are somewhat disturbing. Is the natural history of ureterocele really so benign? We, like other authors, have already observed sometimes severe infectious complications of this type of malformation that required emergency drainage. Isn't endoscopic treatment of intravesical ureteroceles on a single urinary tract usually suf cient? I would tend to share the author's rather pessimistic view on this point. Shouldn't the functional value of the renal pole corresponding to the ureterocele, the presence of re ux in the ipsilateral or even contralateral lower pole, or the presence of detrusor de ciency over the ureterocele be taken into account in the indication for surgery? In conclusion, it appears extremely dif cult to propose a clear-cut therapeutic approach to the various types of ureteroceles, apart from considering that, after possible endoscopic drainage during the postnatal period, persistence of re ux or the appearance of infectious complications requires a complete reconstruction procedure (upper pole nephrectomy, corresponding ureterectomy), ureterocelectomy with vesicourethral reconstruction, reimplantation of the ureter of the lower renal pole: we all know that this type of ``ideal'' operation is technically complex and often disappointing.