URINARY TRACT DUPLICATION IN CHILDHOODBY

J. H. JOHNSTONFrom Alder Hey Hospital, Liverpool

(RECEIVED FOR PUBLICATION OCTOBER 10, 1960)

The incidence of duplication of the urinary tracthas variously been estimated by different authorsto be between the extremes of 0-6% (Campbell,1951) and 6% (Thompson and Amar, 1958) ofindividuals. The anomaly may remain symptom-less and undetected throughout life, but it carriesa predisposition to pathological complications, themost severe and urgent of which occur in earlychildhood, at which age ureteric duplication is notinfrequently a urological emergency.

EmbryologyUreteric duplication follows the formation, at

about the fifth week of intrauterine life, of anaccessory ureteric bud the precise site of origin ofwhich determines the ultimate anatomical features.If the bud arises from the main ureter the finalresult is an incomplete duplication with the uretersuniting above the bladder; if it takes origin from themesonephric duct immediately cranial to the mainureter a complete duplication is produced withboth ureters opening separately into the bladder.Since the lower end of the mesonephric duct becomesincorporated in the wall of the urogenital sinus theaccessory ureter is carried caudally, crossing themain one, and its orifice is found, as a rule, belowand medial to the main orifice (Weigert-Meyer law).When the accessory bud arises from the mesonephricduct at a still more cranial site it is carried farthercaudally and its orifice comes to lie outside thebladder in that portion of the urogenital sinuswhich incorporates the mesonephric duct or in thederivatives of the duct itself. Thus, in the male,the accessory ureter may enter the prostatic urethraabove the ejaculatory duct or open into the duct,the seminal vesicle or the vas deferens. In thefemale the orifice may lie in the urethra or in thevestibule adjacent to the urethral meatus; lesscommonly secondary fistulous communication withthe vagina or the uterus, possibly through Gartner'sduct, may develop during prenatal life. Theaccessory ureter most commonly arises from thecranial aspect of the main ureter or of the meso-nephric duct and thus makes contact with the cranial

portion of the metanephrogenic blastema. As aresult, the accessory ureter, the upper extremity ofwhich dilates to form a pelvis without any obviouspelvi-ureteric junction, drains by one, two or threecalyces usually the upper third or less of the doublekidney. The exterior of the kidney may show noevidence of duplicity or a groove may indicate thedivision between the two portions. The pelvi-calyceal systems of each part are, as a rule, entirelyseparate; communication between the two has,however, been described by Beer and Mencher(1938) and by Braasch (1912). Very uncommonlythe accessory ureter takes origin from the caudalaspect of its fellow or of the mesonephric duct andso drains the lower portion of the double kidney.

MaterialThe present review is based on a clinical series of

73 children with complete or incomplete duplicationand of nine cases in which the abnormality was apost-mortem finding. Cases of the minimal degreeof duplication, e.g. the bifid pelvis, have beenexcluded and so too have those in which a super-numerary ureter terminated outside the urinarytract or in the lower urethra in the female, i.e. theso-called ectopic ureter, since in this group thesymptomatology and the diagnostic problems arequite different. Analysis of the series supports thefindings of other authors that duplication, at leastas a clinical problem, is commoner in the femalethan in the male (57: 25), that it is more commonlyunilateral than bilateral (63: 19), that in unilateralcases each side is more or less equally frequentlyaffected (right 35; left 28) and that in bilateral casesthe anatomical pattern is not necessarily symmetrical.Triple ureters were found in two patients andquadruple ureters in one. Associated but unrelatedcongenital abnormalities of the urinary tract werepresent in three patients with, respectively, a horse-shoe kidney, a large vesical diverticulum of con-genital type and urethral valves. Although uretericduplication is initiated at an early phase ofembryoniclife the responsible stimulus appears, in most cases,to act locally since obvious extra-urinary congenital

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abnormalities were not present in any patient in thepresent clinical series. Complicated or uncom-plicated duplication was found at operation in onepatient with exomphalos and at necropsy in sixinfants with other gross anomalies such as oeso-phageal atresia, imperforate anus, achondroplasia,myelomeningocele, diaphragmatic hernia and con-genital heart disease. In 15 cases the urinary tractduplication was considered to be purely coincidentaland unrelated to the patient's symptoms. Thesechildren were, for the most part, enuretics or casesof obscure abdominal pain in whom an abdominalradiograph, by showing a large renal shadow, led tointravenous pyelography. Five patients complainedof recurrent loin pain on the side of an uncom-plicated, uninfected ureteric duplication.

ComplicationsThe main childhood complications of double

ureters which are of clinical importance fall intotwo groups: (1) anatomical lesions consisting ofobstructive or non-obstructive dilatation of one orboth pyelons, associated with impairment of renalfunction, urinary stasis and infection; (2) chronicor recurrent urinary infection with a reduplicatedbut otherwise anatomically normal urinary tract.Patients with structural complications usuallypresent at a much earlier age than those with infec-tion alone. In this retrospective review of casesit was, in some instances, impossible to determinewith certainty the precise pathologico-anatomicallesion which was present because of incompleteinvestigation before excisional surgery, but it hasbeen possible, excluding the indeterminate cases,to recognize certain specific types of pyelonicdilatation, some of which are peculiar to the dupli-cated urinary tract and some which may also affectthe single ureter. In several cases different lesionswere present in the same patient.The Obstructed Megaureter associated with Ectopic

Ureterocele. Ectopic ureterocele (Fig. 1), withobstruction of the corresponding accessory pyelonleading to its dilatation and to ureteric tortuosity,was found in 11 instances in 10 patients, three maleand seven female. This lesion differs from the'true' ureterocele which occurs with a single,normally sited ureteric orifice in that it is broaderbased, usually larger, more centrally situated andthe ureteric orifice lies, not at the apex of the cysticprotrusion, but towards its lower extremity, at thebladder neck or in the proximal urethra. Theorifice may be small and stenotic, as with the trueureterocele, but more frequently it is of normal sizeor even larger than normal; the obstruction which

causes intravesical ballooning of the lower partof the accessory ureter is due to the position of theorifice relative to the vesical sphincter rather thanto its size. When the sphincter is in its restingstate of tonic contraction it compresses and occludesthe termination of the accessory ureter so that theureter can only empty adequately when the sphincterrelaxes during micturition.The ipsilateral main pyelon was of normal calibre

or only slightly dilated with six of the ureteroceles;in the remaining five it was considerably dilated.In four of these the corresponding ureteric orificewas normal in appearance, without, in at leasttwo cases, vesico-ureteric reflux; there can be littledoubt that the main pyelon dilatation here was theresult of compressive obstruction of its intramuralureter by the ureterocele, particularly since improve-ment in the degree of dilatation and in radiographicfunction followed excision of the ureterocele in twocases (Fig. 2a and b). In one patient the twinpyelon had the features of the idiopathic megaureter.

It might be expected that an ectopic ureteroceleencroaching, as it does, on the vesical outlet wouldinterfere with micturition and lead to chronicvesical retention of urine. In fact, this occurredin only two of our patients, both male, in whomthe bladder was persistently distended, trabeculatedand somewhat hypertrophied. Even in these casesthe obstructive effects were not particularly severesince, in both, the renal tract opposite to the uretero-cele was undilated. The low incidence of dysuriawith ectopic ureterocele was also recorded byEricsson (1954) and by Stephens (1958). It islikely that the emptying and collapse of the uretero-cele during micturition are responsible for thisrelative freedom from urethral obstruction.The ectopic ureterocele usually leads to symptoms

in early infancy; seven of our patients were less than5 months old. These children were seriously illwith symptoms of vomiting, failure to thrive andapparent pain and all had gross pyuria. In onebaby girl the ureterocele prolapsed through theurethra. Intravenous pyelography does not, as arule, demonstrate the dilated accessory pyelon owingto depressed renal function but the ureterocele maybe seen as a round filling defect within the bladdershadow. The ureterocele can usually be seen atcystoscopy, but if it is particularly large it mayobscure visibility and render elucidation difficult.The ureterocele is often palpable on bimanualexamination of the pelvis under anaesthesia whenthe bladder is empty.

The Unobstructed Idiopathic Megaureter. Theunobstructed or 'idiopathic' megaureter (Stephens,

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1956) shows dilatation of the entire pyelon but oftenlittle or no ureteric tortuosity (Fig. 3). There isimpaired concentration on pyelography. Thecharacteristic feature of the lesion is free vesico-ureteric reflux which can be demonstrated at cysto-graphy, sometimes during bladder filling, and alwaysduring micturition when the ureter and usually alsothe pelvis and calyces may become markedly dis-tended with dye (Fig. 4); at the conclusion of voidingthe ureter empties again into the bladder. Atcystoscopy the ureteric orifice is usually seen to bewidely gaping but in some cases its dilatation isonly apparent during the emission of urine or whenreflux occurs with increasing bladder distension.On occasion the orifice, instead of dilating, recedesfrom the bladder, drawing after it the adjacentbladder wall in the form of a diverticulum. Theidiopathic megaureter exhibits variable degrees ofdilatation and renal functional capacity, but in theindividual case these features remain unaltered withthe passage of time, provided infection is controlled

FIG. 1.-Diagram of ob- FIG. 3.-Diagram of the un- (Stephens, 1956); the condition appears to be anstructed megaureter with obstructed idiopathic mega- . ' tectopic ureterocele. The ureter affecting the main Inherent anomaly, the result of a developmentalorifice is compressed and pyelon. defect of the ureteric bud and the related renaloccluded by the vesical parenchyma.sphincter.paecy .

In the well-developed case the diagnosis of theidiopathic megaureter is readily established but its

(a) Aged 2 months; before surgery. The primarily obstructed (b) Six months after excision of the ureterocele. On the left, theleft accessory pvelon does not show. Dilated calyces of the accessory pyelon is now visible and the main pyelon, pelvis and calycessecondarily obstructed left main pyelon are visible. The single are no longer dilated. The hydronephrosis of the right kidney hasright kidney is hydronephrotic and the lumbar ureter is dilated as a subsided; slight ureteric dilatation possibly persists.result of infection.

FIG. 2.-Left ectopic ureterocele; intravenous pyelograms in infant girl.

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mildest extreme is difficult to define precisely anddifferent observers have accepted differing diagnosticcriteria. In this series only those pyelons showingfairly gross changes on intravenous pyelography andmarked distension on reflux from the bladder areconsidered to be of this type. In some cases ofcomplicated duplication with obvious megaureters,non-distending reflux occurred on cystography intotwin or contralateral pyelons which were of normalappearance on intravenous pyelography and it wasthought that, in these instances, the reflux was atemporary effect of infection. It is possible, how-ever, that these pyelons represent the minimaldegree of the idiopathic megaureter.According to our criteria for diagnosis, idio-

pathic megaureter was found in seven patients,each of whom had urinary infection; in three theaccessory and in four the main pyelon was involved.The affected pyelon was visible on intravenouspyelography, although with considerably diminishedconcentration, in three cases; in the remainder itwas radiologically silent. The twin pyelon wasnormal in six cases; in one it was obstructed by anectopic ureterocele. In two cases there was anectopic ureterocele on the other side. The age atdiagnosis in those patients without associatedureterocele was 31 years in one and under 6 monthsin the remainder.

The Simple Obstructed Megaureter. One pyelonin the clinical series had the features of the 'simple'obstructed megaureter of Williams (1958) in whichMurnaghan (1957) has demonstrated that the essen-tial pathology is a functional obstruction in theundilated intramural and, in some cases, the lowerextramural ureter, because of anomalous muscularpatterns in the ureteric wall. In this patient, a boyof 5 years with unilateral duplication, the accessorypyelon was represented by an atretic ureter and amulticystic dysplastic kidney; the main pyelonureter was dilated and tortuous with a normal, non-refluxing ureteric orifice and, at operation, a short,narrow extra vesical segment. In one necropsycase of incomplete duplication the accessory pyelonwas dilated but narrowed just above the point offusion with its twin and it is possible that thismegaureter had a similar pathogenesis.

The Infective Megaureter. Both the obstructedand the unobstructed megaureter may, in the younginfant, be simulated on the intravenous pyelogramby the effects of urinary infection. At this ageinfection may lead to marked dilatation of the upperurinary tract, involving the pelvis and calyces aswell as the ureter, with delay in ureteric emptyingand, in some cases, vesico-ureteric reflux. This

FIG. 4.-The idiopathic megaureter. Cystogram in boy aged7 months, showing reflux into a dilated left main pyelon. Thisportion of the double kidney was not visible on intravenous pyelo-

graphy.

infective megaureter can return to normal in respectboth of dimensions and of competency of the vesico-ureteric sphincter mechanism (Fig. 5a and b). Sincepyuria is present with each type of lesion it may onlybe possible to distinguish them with certainty byrepeated observation after the infection has beencontrolled.

Pelvic Hydronephrosis. Hydronephrosis due toobstruction at the pelvi-ureteric junction, identicalwith that which occurs in the single kidney, wasfound in three clinical cases, children aged 6, 8 and11 years, and at necropsy of a child who died withmultiple abnormalities at the age of 3 days. Ineach case the main pyelon was affected; the absenceof a recognizable pelvi-ureteric junction probablyprecludes the possibility of this lesion occurringin the accessory pyelon.

Radiology and Diagnosis. Radiography of com-plete double ureters, particularly when uretericcatheters are in position, shows localized crossingof the ureters in at least one site and sometimes inthree and it is often stated that ureters obstructone another at these points. In no case in thepresent series was a duplicated ureter dilated to thelevel of a radiological crossing. When the uretersare exposed at operation it is obvious that they liemore or less parallel to one another and that the

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(a) Aged 2 months; hydronephrosis and ureteric dilatationaffecting the main pyelon.

(b) Aged 3 years; the pyelon has returned to normal with theelimination of infection.

FIG. 5.-The infective megaureter; intravenous pyelograms in girl.

localized crossings are more radiologically apparentthan real.

In a structurally complicated ureteric duplicationthere is commonly depressed function of a renalsegment with radiological invisibility of the corre-sponding pyelon; unless the possibility of such alesion is kept in mind in the child with chronicpyuria and cystoscopy performed, its presence mayreadily be overlooked. This is more likely tohappen when only the larger main pyelon is apparenton intravenous pyelography. Suggestive radio-logical features in such cases are: an elongated renalsoft tissue shadow with the visible upper calyx ata distance from the upper pole, a diminution in thenumber of calyces as compared with the oppositeside or, since a non-visualized accessory pyelon isusually dilated, a lateral displacement of the upperpole of the pyelogram, giving the 'drooping flower'appearance or lateral and sometimes downwarddisplacement of the pelvis and the upper ureter.Occasionally, however, the pyelogram may appear

virtually normal. In the type of case with whichthe present review is concerned double uretericorifices will almost certainly be seen at cystoscopyand such procedures as perirenal air insufflation,aortography or operative exploration, which aresometimes necessary for the diagnosis of the ectopicsupernumerary ureter, will rarely be required.When structural complications are present,

ureteric duplication may present a highly complexpicture and, especially in the young infant, it isoften difficult to decide at the time of first assess-ment whether dilatation of a particular pyelonindicates the presence of an intrinsic obstructive ornon-obstructive lesion or is secondary to diseaseof its twin or the result of infection. In such casesthe true pathology may only become apparent byobservation of the effects of conservative treatment,either surgical or medicinal.

Infection without Structural Complications.Urinary infection in association with complete

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URINARY TRACT DUPLICATION IN CHILDHOODor incomplete duplication but without otherapparent anatomical anomaly of the urinary tractexcept, in some cases, slight ureteric dilatation,occurred in 26 children. In 12, 11 girls and oneboy, the infection was transient but in 14, 13 girlsand one boy, it was chronic or recurrent and, inthe latter group at least, presumably associated inmany cases with pyelonephritis, although this wasproved histologically only in one patient. The ageat presentation of these 26 patients was considerablygreater than those with structural complications,the average being 6 years. Increased frequencyand urgency of micturition, nocturnal enuresis ofonset type and attacks of pyrexia, sometimes withloin pain, were the commonest symptoms.The reasons for the apparent increased liability

of the reduplicated but otherwise structurallynormal urinary tract to the development and per-sistence of infection are not known with certainty.Stephens (1956), whose patients were all investigatedby micturating cysto-urethrography, found thatvesico-ureteric reflux and, in cases of incompleteduplication, uretero-ureteric reflux were commonlypresent and considered these to be important patho-genic factors. Since vesico-ureteric reflux may bethe reversible result of urinary infection, distinctionof cause from effect may be difficult and clinicalexperience suggests that reflux is of significance inthe causation of infection only when the volumeof regurgitated urine is large so that a large residueof urine remains after micturition. Reflux is, there-fore, of great importance in respect of infectionwith the idiopathic megaureter in which there is agreatly increased ureteric capacity; it is unlikelythat reflux into a ureter of normal calibre, even if itcauses some ureteric distension, would be ofsufficient quantity to be significant. Forsythe andWhelan (1958) found that vesico-ureteric reflux wascommonly present in enuretic children withouturinary infection. Relatively few of our patientswith urinary infection and a duplicated but un-dilated urinary tract underwent cystography so thatthe incidence of ureteric reflux in these cases is notknown. Reflux was, however, not present in thepatient with histologically proven chronic pyelo-nephritis; in this 6-year-old girl the disease, obviouson intravenous pyelography because of delayedconcentration, small size and approximation ofcalyces, was confined to the lower portion of acompletely reduplicated right kidney.Payne (1959) noted that, in patients with infection

and ureteric duplication, retrograde pyelographysuggested ureteric stasis as dye was still present inthe pelvis or ureter 10 minutes after the injection.Image intensifier studies in five of our cases have,

however, shown no delay in the emptying of un-dilated duplicated ureters.The predisposition of the congenitally hypoplastic,

dysplastic kidney to infection is well recognized.This anomaly, indistinguishable radiologically andmacroscopically from the scarred hypotrophickidney of chronic pyelonephritis, is identifiablehistologically mainly by the presence of primitivetubules, resembling those of the foetal kidney, whichhave a wide lumen and a lining of deeply stainingcubical cells, surrounded by a concentric arrange-ment of loose connective tissue which may containangiomatous material and cartilage. The frequentassociation of gross dysplasia with pyelonephritisraises the question whether lesser degrees of dys-plasia may predispose to the development of pyelo-nephritis in a kidney which appears normal radio-logically. Marshall (1953) considered that persis-tent foetal elements in the renal parenchymaconstitute loci minoris resistentiae to infection andEricsson and Ivemark (1958), who were of the sameopinion, found such elements to be present fre-quently with complicated ureteric duplication.

Histological material was studied from theparenchyma of 42 pyelons from the entire presentseries. Undoubted dysplastic tissue was found inten. In only one of these was the correspondingureter of normal calibre; the remainder was asso-ciated with hydronephrosis and obstructed orunobstructed megaureter or, in one instance, withan atretic ureter. In 20 specimens the renalparenchyma was histologically normal; in 15 ofthese the ureter was normal and in five it wasdilated. Chronic pyelonephritis without dysplasiawas found in 12 specimens; in one the ureter wasnormal and in the remainder it was pathologicallydilated. Many of these last sections showedmarked fibrosis and distortion of renal tissue andit was considered possible, in some instances, thatdysplastic elements might have been present initially,but subsequently became obscured by scarring.In the majority of cases in which a histologicalspecimen was obtained from a renal segmentdrained by a normal pelvis and ureter there weremarked pathological changes in the twin pyelon;no definite conclusions can be drawn from thisseries, owing to the paucity of histological materialfrom a duplicated but otherwise anatomicallynormal urinary tract, concerning the part played bydysplastic elements in predisposing to infection insuch cases. It is apparent, however, that the renalparenchyma is frequently normal when there is nodilatation of the corresponding pyelon and thatdysplasia is usually associated with megaureter andhydronephrosis, as it was in 10 of Marshall's (1953)

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ARCHIVES OF DISEASE IN CHILDHOOD12 cases. In the latter instance it is likely that theurinary stasis resulting from the dilatation of thepyelon is of greater significance in the pathogenesisof infection than the parenchymal anomaly.The embryological sequence of events which

associates a congenitally abnormal ureter with anabnormal renal parenchyma probably differs withthe type of lesion. An inherently defective uretericbud may induce the formation of a defectivekidney or vice versa and it is likely that the non-progressive idiopathic megaureter constitutes sucha primary defect of germ plasm. The kidneyparenchyma in three of our six cases, from whichhistology is available, contained dysplastic tissueand it was considered to be present possibly in afurther one. With the obstructed megaureter theureteric and renal anomalies may both be the resultof obstruction; renal dysplasia is not uncommonlyfound with the dilated urinary tract resulting fromurethral valves. A urinary obstruction present atan early period of foetal life appears to interferewith the maturation of the developing nephrons andalso with the development of the ureteric muscula-ture; this is of clinical prognostic importance in that,although some improvement in the degree of uretericdilatation and in radiological renal function may,in some cases, follow the post-natal relief of pre-natal obstruction, complete restoration to normalis never possible. The renal parenchyma from threeof our six cases of ectopic ureterocele showeddysplasia and in two others its presence was thoughtpossible; one of the specimens from the two cases ofsimple megaureter was dysplastic.

Treatment

The patient with ectopic ureterocele commonlypresents in infancy with acute symptoms of urinaryobstruction and infection and in these cases theimmediate essential is the provision of free drainageof the obstructed ureter into the bladder. Grossand Clatworthy (1950) advocated, for this purpose,a small incision only in the ureterocele wall in orderto prevent subsequent vesico-ureteric reflux. It has,however, been our experience, and also that ofEricsson (1954) that, both in the ectopic and the trueureterocele, simple incision does not prevent refluxand it carries the disadvantages that the smallopening may diminish in size as the ureter shrinksand also that the residual redundant cyst wall maylead to later complications; in one of our patientsit caused a flap valve effect at the bladder neckwhich interfered with micturition and necessitateda second operation. Excision of the ureteroceleby open operation is therefore preferable in that it

ensures drainage and carries no disadvantage ascompared with incision in respect of reflux. In-cision or excision of seven ectopic ureteroceles wasperformed in the present series. The involvedpyelon showed improved function, or visibility forthe first time, on intravenous pyelography in threeinstances (Fig. 2a and b); in all cases pyuria andureteric dilatation persisted. Ericsson (1954) foundsimilar radiographic improvement, but persistenceof infection, in nine of 10 cases. Improved drainageof a secondarily obstructed ipsilateral main pyelon,as shown by improved radiographic function and adiminution in the degree of dilatation, resulted fromdecompression of the ureterocele in two of fourcases (Fig. 2a and b). Some period of time mustoften elapse before free drainage becomes effectiveand the time factor may be of great importancewhen the contralateral renal function is defectiveor in cases of bilateral ectopic ureterocele. Thiswas exemplified by one patient who required some-what unorthodox management.

Case Report. J.S., a baby girl, was admitted tohospital at the age of 11 days with pyrexia, vomiting anddiarrhoea. Her urine contained a large amount of pusand grew Esch. coli and S. viridans on culture. Intravenouspyelography showed the faint shadows of bilateralhydronephrotic kidneys. Cystoscopy revealed bilateralectopic ureteroceles; above each ureterocele was anormal ureteric orifice. There was no reflux into anyof the ureters on micturating cystography. At operation,when the child was 4 weeks old, the ureteroceles wereexcised by open transvesical operation; the right drainedthrough a large orifice into the proximal urethra butno orifice could be found on the left ureterocele. Thechild's general condition gradually deteriorated afteroperation; swinging fever and repeated vomiting per-sisted and she failed to gain any weight. In spite ofantibiotic therapy the urine was persistently infected.The blood urea rose to a maximum of 120 mg. %0.Intravenous pyelography six weeks after operation showedno concentration by the right double kidney; on theleft, only the main pyelon was visible, showing hydro-nephrosis and a dilated tortuous ureter with markeddelay in emptying of the ureter into the bladder (Fig. 6a).Clinically the child appeared to empty her bladdercompletely. It was apparent that her failure to improvewas the result of persistent impairment of drainageof the sole pyelon retaining significant function and thatdecompression of this pyelon was essential. Tubenephrostomy has, in our experience of such urinaryobstruction, been of very temporary benefit only; thepresence of an indwelling tube for more than a week orso invariably leads to the exacerbation of infection andto the patient's deterioration. A left cutaneous uretero-stomy was therefore performed, both left ureters beingdivided just above the bladder and brought out in theleft iliac fossa (Fig. 6b). The child's general conditionshowed an almost immediate and striking improvement

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(a)

FvG. 6.--J.S., baby girl with bilateral ectopic ureteroceles.

(a) Intravenous pyelogram six weeks after excision of the uretero-celes. The right pyelons and the left accessory pyelon do not show.Impaired drainage of the left main pyelon persists. Radiographtaken 80 minutes after injection.

(b) Temporary left cutaneous ureterostomy. Both left uretershave been divided near the bladder and drain on the surface.

(c) Intravenous pyelogram three months after reimplantationof the left ureters into the bladder. Both left pyelons are visible,showing moderate dilatation. Neither right pyelon shows.

(c)

and she was discharged home two weeks later on aurinary antiseptic. Intravenous pyelography six monthslater again showed no dye concentration on the rightside. On the left, both pyelons were now visible, eachshowing moderate hydronephrosis and hydroureter;a small calculus was present in the accessory ureter.The child had continued to pass urine in small quantitiesthrough the urethra. Six months after the uretero-stomy had been performed the left double ureters werereimplanted into the bladder, bringing them obliquelythrough the bladder wall in the hope of preventingreflux, and the small mobile calculus was removed.Three months after the reimplantation, intravenouspyelography again showed no concentration by theright double kidney; both pyelons on the left showed

good concentration of the dye but moderate dilatationremained (Fig. 6c). Six months later the child is welland thriving. Mild pyuria and bacilluria persist in spiteof prolonged chemotherapy.

Although radiographic improvement may beapparent after decompression of an ectopic uretero-cele, dilatation of the accessory ureter and pyuriaalmost invariably persist and heminephrectomy andureterectomy are indicated if the remainder of theurinary tract has returned to normal and the in-volved pyelon is thus not essential to the patient.Excisional surgery should be carried out as aprimary procedure if disease is limited to the one

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ARCHIVES OF DISEASE IN CHILDHOODpyelon and there are no secondary effects on theothers. Heminephrectomy or nephrectomy wasperformed in seven cases in the present series.

Surgery is not required urgently with the un-obstructed megaureter associated with duplication;a period of antibiotic treatment is of value, notonly therapeutically, but also in allowing a moreprecise assessment of the pathology and, particularlyin the young infant, in distinguishing intrinsicanomalies from reversible effects produced by infec-tion. The treatment of the idiopathic megaureterdepends upon its functional capacity and upon theintegrity of the remainder of the urinary tract.Excision of the involved pyelon, which was perform-ed in six of our cases, is preferable if it is dispensablebecause the free vesico-ureteric reflux, as with alarge vesical diverticulum, leads to the accumulationof residual urine which promotes infection andendangers not only the anomalous pyelon, but alsothe others. When retention of the pyelon is essentialthe residual urine in the ureter and bladder may,in the child of co-operative age, be diminished oreven eliminated by having the patient micturateevery two hours and, at each occasion, empty thebladder three times at two-minute intervals(Stephens, 1956). By this means and by the pro-longed use of urinary antiseptics deterioration inrenal function may be prevented. Plastic operationsat the uretero-vesical junction such as those des-cribed by Bischoff (1957) and by Hutch (1952),which aim at preventing vesico-ureteric reflux,have not been employed in any case in this seriesbut they have, in our experience, been applied withsuccess to the idiopathic megaureter involving asingle pyelon; it appears likely that, with slightmodification in technique, they could be used forthe duplicated ureter.Heminephrectomy presents few technical problems

in cases of ureteric duplication. The line of divisionof the kidney may be apparent as a groove on thesurface; frequently the diseased portion is firmerto palpation than the normal or is hydronephroticso that it is nearly always possible to excise onepyelon without opening the pelvi-calyceal system ofthe other. It is important that the ureter is com-pletely removed; a residual stump of ureter, not onlyin the case of the idiopathic megaureter but alsoin that of the ectopic ureterocele, particularly if theureterocele has previously been incised or excised,acts as a diverticulum, leading to the persistence ofinfection and possibly, as occurred in one of ourcases, to calculus formation. The double uretersoften share a common wall in the lowest inch or twoand, in order to avoid injury to the twin ureter orto its blood supply, only that part of the diseased

ureter which is unattached to its twin must beresected, leaving the common wall intact; theresulting small aperture in the bladder at the siteof the ureteric orifice requires a suture.The simple megaureter did not present as a

clinical problem in the present series. When itdoes so, treatment depends upon whether the in-volved pyelon is dispensable or must be retained.In the latter instance reimplantation of the ureterinto the bladder or uretero-ureterostomy (Rothfeld,1960) may be indicated.The treatment of hydronephrosis due to obstruc-

tion at the pelvi-ureteric junction is the same in theduplicated kidney as in the single organ. In oneof our cases pyeloplasty was performed; in theothers, nephrectomy or heminephrectomy.

In the treatment of loin pain associated withuncomplicated ureteric duplication, Gutierrez (1944)recommended upper segment heminephrectomy inthe adult because of presumed 'impaired uretericdynamism'. This procedure has little or no justi-fication in the child. In our five patients with loinpain the symptom was only occasional and did notappear to be severe.The treatment of the older child with chronic or

recurrent urinary infection associated with uretericduplication, but without complicating hydro-nephrosis or megaureter, differs little from that of thepatient without duplication; it consists mainly inthe prolonged administration of urinary antisepticsand the prevention of reinfection by the avoidanceof constipation, the elimination of obvious septicfoci and, in the girl, local cleanliness. Gross (1953),in the belief that duplicated ureters are mutuallyobstructive, advocated upper segment heminephrec-tomy and ureterectomy in order to promote drainagefrom the lower and larger portion of the kidney.Unless, however, impaired ureteric drainage can bedemonstrated radiologically, and this was not so infive of our cases of this type examined by the imageintensifier, excisional surgery does not appear to bejustifiable; its sole indication is in the unusual casein which chronic pyelonephritis can be shown to beconfined to a dispensable renal segment. In themajority of children with recurrent urinary infectionthe attacks tend to cease at about puberty (Williams,1958), but it must be presumed that each episodeis associated with pyelonephritis and with furtherimpairment of renal function. These patientsrequire prolonged frequent supervision; repeatedpyelographic examinations, with the object offinding indications for surgery, are of doubtfulvalue. In our experience anomalies such asmegaureter and hydronephrosis or pyelographicevidence of hypoplasia or pyelonephritis have always

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URINARY TRACT DUPLICATION IN CHILDHOOD 189been present at the initial investigation; we havenot observed them develop de novo during obser-vation extending, in many cases, over a period ofseveral years.

SummaryA series of 82 cases of ureteric duplication in

children is described. The complications foundwere of two types: first, structural lesions whichincluded ectopic ureterocele, unobstructed idio-pathic megaureter, simple obstructed megaureter,infective megaureter and pelvic hydronephrosis;second, urinary infection with a duplicated butotherwise apparently structurally normal urinarytract. The pathogenesis and treatment of thevarious complications are discussed. Attention isdrawn to the value of temporary cutaneous uretero-stomy in the treatment of the patient with ectopicureterocele and secondary obstruction of the mainpyelon which persists after decompression of theureterocele.

I am indebted to Miss Isabella Forshall and Mr. P. P.Rickham for permitting me to include their cases forthe purpose of this review, and to Dr. E. G. Hall andDr. J. Bouton for advice on the interpretation of renalhistopathology.

REFERENCES

Beer, E. and Mencher, W. H. (1938). Heminephrectomy in diseaseof the double kidney. Report of fourteen cases. Ann. Surg.,108, 705.

Bischoff, P. (1957). Megaureter. Brit. J. Urol., 29, 416.Braasch, W. F. (1912). The clinical diagnosis of congenital anomaly

in the kidney and ureter. Ann. Surg., 56, 726.Campbell, M. (1951). Clinical Pediatric Urology. Saunders,

Philadelphia and London.Ericsson, N. 0. (1954). Ectopic ureterocele in infants and children:

Clinical study. Acta Chir. Scand. Suppl., 197.and Ivemark, B. 1. (1958). Renal dysplasia and urinary-tract

infection. Ibid., 115, 58.Forsythe, W. I. and Whelan, R. F. (1958). The occurrence and

significance of vesico-ureteral reflux in children. Brit. J. Urol.,30, 189.

Gross, R. E. (1953). The Surgery of Infancy and Childhood; itsPrinciples and Techniques. Saunders, Philadelphia and London.and Clatworthy, H. W., Jr. (1950). Ureterocele in infancy andchildhood. Pediatrics, 5, 68.

Gutierrez, R. (1944). Double kidney as a source of impaireddynamism; its surgical treatment by heminephrectomy. Amer.J. Surg., 65, 256.

Hutch, J. A. (1952). Vesico-ureteral reflux in the paraplegic: causeand correction. J. Urol. (Baltimore), 68, 457.

Marshall, A. G. (1953). The persistence of foetal structures inpyelonephritic kidneys. Brit. J. Surg., 41, 38.

Murnaghan, G. F. (1957). Experimental investigation of thedynamics of the normal and dilated ureter. Brit. J. Urol.,29, 403.

Payne, R. A. (1959). Clinical significance of reduplicated kidneys.Ibid., 31, 141.

Rothfeld, S. H. (1960). Uretero-ureterostomy: A means of con-servation of renal tissue. J. Urol. (Baltimore), 84, 60.

Stephens, F. D. (1956). Double ureter in the child. Aust. N.Z.J. Surg., 26, 81.(1958). Ureterocele in infants and children. Ibid., 27, 288.

Thompson, I. M. and Amar, A. D. (1958). Clinical importance ofureteral duplication and ectopia. J. Anmer. med. Ass., 168, 881.

Williams, D. I. (1958). Urology in Childhood. Vol. 15 (Handbuchder Urologie). Springer, Berlin.

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