Arch Dis Child: first published as 10.1136/adc.36.186.180 on 1 April 1961. Downloaded from URINARY TRACT DUPLICATION IN CHILDHOOD BY J. H. JOHNSTON From Alder Hey Hospital, Liverpool (RECEIVED FOR PUBLICATION OCTOBER 10, 1960) The incidence of duplication of the urinary tract portion of the metanephrogenic blastema. As a has variously been estimated by different authors result, the accessory ureter, the upper extremity of to be between the extremes of 0-6% (Campbell, which dilates to form a pelvis without any obvious 1951) and 6% (Thompson and Amar, 1958) of pelvi-ureteric junction, drains by one, two or three individuals. The anomaly may remain symptom- calyces usually the upper third or less of the double less and undetected throughout life, but it carries kidney. The exterior of the kidney may show no a predisposition to pathological complications, the evidence of duplicity or a groove may indicate the most severe and urgent of which occur in early division between the two portions. The pelvi- childhood, at which age ureteric duplication is not calyceal systems of each part are, as a rule, entirely infrequently a urological emergency. separate; communication between the two has, however, been described by Beer and Mencher Embryology (1938) and by Braasch (1912). Very uncommonly Ureteric duplication follows the formation, at the accessory ureter takes origin from the caudal about the fifth week of intrauterine life, of an aspect of its fellow or of the mesonephric duct and accessory ureteric bud the precise site of origin of so drains the lower portion of the double kidney. which determines the ultimate anatomical features. copyright. If the bud arises from the main ureter the final Material result is an incomplete duplication with the ureters The present review is based on a clinical series of uniting above the bladder; if it takes origin from the 73 children with complete or incomplete duplication mesonephric duct immediately cranial to the main and of nine cases in which the abnormality was a ureter a complete duplication is produced with post-mortem finding. Cases of the minimal degree both ureters opening separately into the bladder. of duplication, e.g. the bifid pelvis, have been Since the lower end of the mesonephric duct becomes excluded and so too have those in which a super- http://adc.bmj.com/ incorporated in the wall of the urogenital sinus the numerary ureter terminated outside the urinary accessory ureter is carried caudally, crossing the tract or in the lower urethra in the female, i.e. the main one, and its orifice is found, as a rule, below so-called ectopic ureter, since in this group the and medial to the main orifice (Weigert-Meyer law). symptomatology and the diagnostic problems are When the accessory bud arises from the mesonephric quite different. Analysis of the series supports the duct at a still more cranial site it is carried farther findings of other authors that duplication, at least caudally and its orifice comes to lie outside the as a clinical problem, is commoner in the female bladder in that portion of the urogenital sinus than in the male (57: 25), that it is more commonly on September 30, 2021 by guest. Protected which incorporates the mesonephric duct or in the unilateral than bilateral (63: 19), that in unilateral derivatives of the duct itself. Thus, in the male, cases each side is more or less equally frequently the accessory ureter may enter the prostatic urethra affected (right 35; left 28) and that in bilateral cases above the ejaculatory duct or open into the duct, the anatomical pattern is not necessarily symmetrical. the seminal vesicle or the vas deferens. In the Triple ureters were found in two patients and female the orifice may lie in the urethra or in the quadruple ureters in one. Associated but unrelated vestibule adjacent to the urethral meatus; less congenital abnormalities of the urinary tract were commonly secondary fistulous communication with present in three patients with, respectively, a horse- the vagina or the uterus, possibly through Gartner's shoe kidney, a large vesical diverticulum of con- duct, may develop during prenatal life. The genital type and urethral valves. Although ureteric accessory ureter most commonly arises from the duplication is initiated at an early phase ofembryonic cranial aspect of the main ureter or of the meso- life the responsible stimulus appears, in most cases, nephric duct and thus makes contact with the cranial to act locally since obvious extra-urinary congenital 180 Arch Dis Child: first published as 10.1136/adc.36.186.180 on 1 April 1961. Downloaded from URINARY TRACT DUPLICATION IN CHILDHOOD 181 abnormalities were not present in any patient in the causes intravesical ballooning of the lower part present clinical series. Complicated or uncom- of the accessory ureter is due to the position of the plicated duplication was found at operation in one orifice relative to the vesical sphincter rather than patient with exomphalos and at necropsy in six to its size. When the sphincter is in its resting infants with other gross anomalies such as oeso- state of tonic contraction it compresses and occludes phageal atresia, imperforate anus, achondroplasia, the termination of the accessory ureter so that the myelomeningocele, diaphragmatic hernia and con- ureter can only empty adequately when the sphincter genital heart disease. In 15 cases the urinary tract relaxes during micturition. duplication was considered to be purely coincidental The ipsilateral main pyelon was of normal calibre and unrelated to the patient's symptoms. These or only slightly dilated with six of the ureteroceles; children were, for the most part, enuretics or cases in the remaining five it was considerably dilated. of obscure abdominal pain in whom an abdominal In four of these the corresponding ureteric orifice radiograph, by showing a large renal shadow, led to was normal in appearance, without, in at least intravenous pyelography. Five patients complained two cases, vesico-ureteric reflux; there can be little of recurrent loin pain on the side of an uncom- doubt that the main pyelon dilatation here was the plicated, uninfected ureteric duplication. result of compressive obstruction of its intramural ureter by the ureterocele, particularly since improve- Complications ment in the degree of dilatation and in radiographic function followed excision of the ureterocele in two The main childhood complications of double cases (Fig. 2a and b). In one patient the twin ureters which are of clinical importance fall into pyelon had the features of the idiopathic megaureter. two groups: (1) anatomical lesions consisting of It might be expected that an ectopic ureterocele obstructive or non-obstructive dilatation of one or encroaching, as it does, on the vesical outlet would both pyelons, associated with impairment of renal interfere with micturition and lead to chronic function, urinary stasis and infection; (2) chronic vesical retention of urine. In fact, this occurred or recurrent urinary infection with a reduplicated in only two of our patients, both male, in whom but otherwise anatomically normal urinary tract. the bladder was persistently distended, trabeculated copyright. Patients with structural complications usually and somewhat hypertrophied. Even in these cases present at a much earlier age than those with infec- the obstructive effects were not particularly severe tion alone. In this retrospective review of cases since, in both, the renal tract opposite to the uretero- it was, in some instances, impossible to determine cele was undilated. The low incidence of dysuria with certainty the precise pathologico-anatomical with ectopic ureterocele was also recorded by lesion which was present because of incomplete Ericsson (1954) and by Stephens (1958). It is investigation before excisional surgery, but it has likely that the emptying and collapse of the uretero- been possible, excluding the indeterminate cases, cele during micturition are responsible for this http://adc.bmj.com/ to recognize certain specific types of pyelonic relative freedom from urethral obstruction. dilatation, some of which are peculiar to the dupli- The ectopic ureterocele usually leads to symptoms cated urinary tract and some which may also affect in early infancy; seven of our patients were less than the single ureter. In several cases different lesions 5 months old. These children were seriously ill were present in the same patient. with symptoms of vomiting, failure to thrive and The Obstructed Megaureter associated with Ectopic apparent pain and all had gross pyuria. In one Ureterocele. Ectopic ureterocele (Fig. 1), with baby girl the ureterocele prolapsed through the on September 30, 2021 by guest. Protected obstruction of the corresponding accessory pyelon urethra. Intravenous pyelography does not, as a leading to its dilatation and to ureteric tortuosity, rule, demonstrate the dilated accessory pyelon owing was found in 11 instances in 10 patients, three male to depressed renal function but the ureterocele may and seven female. This lesion differs from the be seen as a round filling defect within the bladder 'true' ureterocele which occurs with a single, shadow. The ureterocele can usually be seen at normally sited ureteric orifice in that it is broader cystoscopy, but if it is particularly large it may based, usually larger, more centrally situated and obscure visibility and render elucidation difficult. the ureteric orifice lies, not at the apex of the cystic The ureterocele is often palpable on bimanual protrusion, but towards its lower extremity, at the examination of the pelvis under anaesthesia when bladder neck or in the proximal urethra. The the bladder is empty. orifice may be small and stenotic, as with the true ureterocele, but more frequently it is of normal size The Unobstructed Idiopathic Megaureter. The or even larger than normal; the obstruction which unobstructed or 'idiopathic' megaureter (Stephens, 6 Arch Dis Child: first published as 10.1136/adc.36.186.180 on 1 April 1961.