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Ureteral Reimplantation in Infants
0022-534 7 /93/1504-1460$03.00/0 THE JOURNAL OF UROLOGY Copyright © 1993 by AMERICAN UROLOGICAL ASSOCIATION, INC.
Vol. 150, 1460-1462, November 1993 Printed in U. S.A.
URETERAL REIMPLANTATION IN INFANTS SAUL P. GREENFIELD , JOHN J. GRISWOLD AND JULIAN WAN From the Department of Urology, Children's Hospital of Buffalo, State University of New York, Buffalo, New York
ABSTRACT
Between 1984 and 1990, 30 infants (46 ureters) 8 weeks to 6 months old (mean age 4 months) underwent ureteral reimplantation. Weight at operation ranged from 4.9 to 9.5 kg. (mean 6.9) . Underlying abnormalities were primary vesicoureteral reflux (28 ureters) , primary ureterovesical junction obstruction ( 1 1 ) , ectopic ureterocele (4) and ectopic ureter (3) . Patients with reflux underwent surgery because of high grade reflux (grade IV or V) or breakthrough infection. Infants with primary ureterovesical junction obstruction underwent obstructive diethylenetriaminepenta acetic acid diuretic renograms. Reimplantations performed included 44 Glenn-Anderson advance ments, 1 Cohen cross-trigonal advancement and 1 Politano-Leadbetter procedure. Of the ureters 30 (65 % ) were tapered intravesically. Ureteral stents were used in all instances. Transient ureteral obstruction developed in 2 children following stent removal and 1 required temporary percutaneous nephrostomy drainage. No permanent ureterovesical obstruction was noted in any patient. Followup at 18 months revealed no postoperative reflux in 43 of 46 ureters (93 % ) . One infant required repeat reimplantation to correct a vesicoureteral fistula and the remaining 2 patients ( 2 ureters) with l o w grade reflux (grade I and II) are being observed. Surgery was successful i n 2 7 of 30 tapered ureters (90 % ) and in all 1 6 of the nontapered ureters ( 100 % ) . While the majority of infants with ureterovesical junction abnormalities may be observed, some may require surgery. Reimplantation, when necessary in this age group, can be performed with a high degree of success and diverting procedures such as vesicostomy or ureterostomy can be avoided. KEY WORDS: infant, vesico-ureteral reflux, ureteral obstruction
The advent of prenatal and early postnatal ultrasound screening has identified more infants with congenital hydro nephrotic conditions. 1-3 Specifically, abnormalities of the ure terovesical junction, including primary vesicoureteral reflux, ureterovesical junction obstruction, ectopic ureter and dupli cation anomalies, are being diagnosed with much greater fre quency within the first few months of life. The natural history of many of these early diagnosed conditions is unknown. Many, if not most, of these infants can be managed nonoperatively, since spontaneous improve ment and resolution of these abnor malities may occur with time. 1 • 4 However, some infants with uncontrollable infections, high grade vesicoureteral reflux or ureterovesical obstruction may benefit from surgical interven tion. Others with static anatomical abnormalities that will not resolve with time, such as ectopic ureters or ureteroceles with functioning renal moieties , may also require reimplantation. Success rates in older children of greater than 95 % with a variety of antireflux procedures are well documented. 5 - 7 There fore, we present a group of infants with a variety of underlying abnormalities who underwent early reimplantation and com pare the outcome with that in older patients. MATERIALS AND METHO D S
Between 1984 and 1990, 18 male and 12 female infants ( 46 ureters) less than 6 months old (range 8 weeks to 6 months, mean age 4 months) underwent ureteral reimplantation. There were 6 infants 8 weeks to 3 months old, 9 infants 3 to 4 months old, 9 infants 4 to 5 months old and 6 infants 5 to 6 months old. A unilateral operation was done in 15 infants, bilateral procedures were done in 13 and reimplantation was performed in 2 with a solitary functioning renal unit. Three reimplanta tions were performed upon complete ureteral duplications. Weight at operation ranged from 4.9 to 9.5 kg. (mean 6.9). A total of 10 infants (33 % ) presented with febrile urinary tract infections, 9 (30%) had hydronephrosis discovered by maternal prenatal ultrasound and 8 (26%) were identified by
early postnatal screening ultrasonography. Two other infants ( 7 % ) were discovered incidentally during cardiac catheteriza tion (1) and a radionuclide bone scan ( 1 ) . One infant (3%) was investigated for a palpable abdominal mass. All patients underwent abdominal ultrasonography and con trast voiding cystourethrography. Upper tract contrast medium or radionuclide imaging was delayed until age 1 month. Upper tract images obtained included excretory urography (IVP) in 28 patients, 99mtechnetium ( 99mTc)-dimercaptosuccinic acid renal scan in 8 and 99mTc-glucoheptonate renal scan in 12. In addition, 99 mTc-diethylenetriaminepentacetic acid (DTPA) renal scans with furosemide were performed in 14 infants suspected of having obstruction, defined as an emptying half time of greater than 20 minutes. 8 The most common diagnosis was vesicoureteral reflux (28 ureters) . All ureters showed high grade reflux (grade IV or V) except for 3 (grade II or III) in patients with high grade contralateral reflux. Ureterovesical junction obstruction was present in 1 1 ureters, ureteral ectopia in 3 and an ectopic ureterocele with an adequately functioning upper pole segment in 4 (see table) . Contralateral ureters without reflux or obstruc tion were not reimplanted. Five infants ( 1 7 % ) had break through urinary tract infections while on prophylactic anti biotics and 4 of those required hospitalization for treatment of urosepsis preoperatively. Reimplantation was done by the Glenn-Anderson advance ment technique in 44 ureters (28 patients) , the Cohen cross trigonal advancement ( 1 ) and the Politano-Leadbetter proce dure ( 1 ) . Greatly dilated ureters were treated with excisional
Accepted for publication April 30, 1993. 1460
Diagnosis of reimplanted ureter Diagnosis
No. Pts.
No. Ureters ( % )
Vesicoureteral reflux U reterovesical junction obstruction Ectopic ureter Ectopic ureterocele Totals
16 9 3 2 30
28 (61) 1 1 (24) 3 (7) ..!_Jfil 46 ( 100)
1461
URETERAL R.EIMPLANTATIO N IN INFANTS
tapering of the intravesical segment. Nontapered ureters were stented with an infant feeding tube (3F or 5F) for 6 days and tapered ureters for 9. The bladder was drained in all patients with a suprapubic catheter, which was removed 1 day after removal of the stents. Hospitalization ranged from 6 to 11 days (mean 8.2) for nontapered reimplantations and 9 to 26 days (mean 11.6) for tapered reimplantations. Followup ranged from 1.5 to 6.5 years (mean 3 . 1). Postoper ative surveillance consisted of urine cultures, contrast voiding cystourethrograms and IVPs at 6 months and 18 months post operatively. Diuretic (furosemide) DTPA renal scans were per formed in all patients postoperatively who had undergone sur gery for ureterovesical junction obstruction and whose prior scans showed obstruction. RESULTS
Two infants who had undergone ureteral reimplantation with tapering had in-hospital complications (transient ureteral ob struction immediately after stent removal). One infant im proved with hydration alone, while 1 required temporary per cutaneous nephrostomy drainage. Postoperative upper tract imaging revealed stable or improved drainage in all instances. All postoperative DTPA scans revealed nonobstructive wash out curves in patients who underwent surgery for primary obstruction. Followup voiding cystourethrograms at 6 months revealed no evidence of reflux in 39 ureters (85%) and persistent reflux in 7, all grade I or II. Radiographic studies were repeated in all infants at 18 months. In 2 infants the reflux resolved sponta neously and 1 with persistent reflux into 2 ureters underwent cystoscopic lysis of intravesical bands with subsequent resolu tion. Presently, 2 patients are being followed with persistent low grade (grades I and II) reflux. Both had undergone ureteral tapering for primary obstructive megaureter: 1 bilaterally (age 8 weeks) and 1 unilaterally (age 4 months). One patient required repeat reimplantation (3 % ) for correction of a vesicoureteral fistula after tapered bilateral reimplantation for high grade reflux at age 4 months. No patients who had undergone reim plantation without tapering had postoperative reflux. An ex ample is provided in figures 1 and 2. Finally, 5 of the 15 infants (33 % ) who underwent unilateral reimplantation had new low grade (grade I or II) contralateral reflux and they are all being observed. Overall, a successful outcome was achieved in 43 of 46 ureters reimplanted (93 %) or 27 of 30 patients (90 %). Surgery was successful in 27 of 30 tapered reimplantations (90%) and in all 16 nontapered reim plantations (100% ).
FIG. 2. IVP at age 2 years. Bilateral reimplantation was performed at age 8 weeks. DTPA renal scans with furosemide confirmed absence of residual obstruction. DISCUSSION
The widespread screening of fetuses with prenatal ultrasound has markedly increased the number of newborns being iden tified with hydronephrotic conditions. A significant number of these infants will ultimately have abnormalities of the ureterovesical junction. Of 187 neonatal hydronephrotic units identified prenatally by Homsy et al 13.4% and 9. 1 % had ureterovesical junction obstruction and vesicoureteral reflux, respectively.'3 Recent series on infants with primary obstructive megaureters report that 52 to 72% of the cases were discovered prenatally. 4 ' 9 Infants with prenatally diagnosed vesicoureteral reflux differ from older presenting children in that they have higher grades of reflux (65% grades IV or V) and male infants predominate (84 to 91%). 1 ' By contrast, in a review of 545 children of all ages with reflux, grade IV or V reflux was noted in 7.6% and only 15% were boys. 1 0 There is controversy surrounding the management of these newborns. Keating et al reported that 20 of 23 primary obstruc tive megaureters diagnosed prenatally (87%) were managed nonoperatively and renal function did not deteriorate. 4 Con versely, Peters et al reported on the successful outcome in infants less than 8 months old who underwent ureteral reim plantation for primary ureterovesical junction obstruction, sug gesting the necessity for early surgery. 9 The natural history over a long period of massively dilated refluxing ureters diag nosed prenatally or early in infancy is unknown. However, Gordon et al suggested that these infants may be managed expectantly, since spontaneous resolution is possible. 1 They observed cessation of reflux in 35% of the ureters followed for a mean of 2. 1 years and effective antibiotic prophylaxis in 80% of the patients followed. This is in contradistinction to findings in studies of older children, which showed that grade IV or V reflux rarely resolves spontaneously. 10 Therefore, the role of early surgery is an unresolved issue 2
FIG. 1. Percutaneous nephrostograms show high grade bilateral ure terovesical junction obstruction in newborn diagnosed prenatally. Note that no contrast medium enters bladder. Antenatal ultrasound had shown bilateral hydroureteronephrosis and oligohydramnios. A, right side. B, left side.
1462
URETERAL REIMPLANTATION IN INFANTS
and remains controversial. While many infants with congenital abnormalities of the ureterovesical junction may be managed nonoperatively, some may require surgery because of uncon trollable urinary tract infections or high grade obstruction. In addition, in a number of infants with massively dilated ureters secondary to vesicoureteral reflux the reflux will never resolve. Others with ectopic ureters and ureteroceles with well function ing renal moieties will require definitive correction, since spon taneous resolution will not occur. Our success rates of 100% in nontapered reimplants and 90% in tapered reimplants compare favorably with previous operative rates of success in older children. One need not delay an operation or propose temporary diverting procedures, such as vesicostomy or ureterostomy, if reimplantation is necessary or ultimately will be required. REFERENCES
1. Gordon, A. C., Thomas, D. F., Arthur, R. J., Irving, H. C. and Smith, S. E.: Prenatally diagnosed reflux: a follow-up study. Brit. J. Urol., 65: 407, 1990. 2. Anderson, P. A. M. and Rickwood, A. M. K.: Features of primary vesicoureteric reflux detected by prenatal sonography. Brit. J. Urol., 67: 267, 1991.
3. Homsy, Y. L., Saad, F., Laberge, I., Williot, P . and Pison, C.: Transitional hydronephrosis of the newborn and infant. J. Urol., part 2, 144: 579, 1990. 4. Keating, M. A., Escala, J., Snyder, H. McC., III, Heyman, S. and Duckett, J. W.: Changing concepts in management of primary obstructive megaureter. J. Urol., part 2, 142: 636, 1989. 5. Carpentier, P. J., Bettink, P. J., Hop, W. C. J. and Schroder, F. H.: Reflux-a retrospective study of 100 ureteric reimplantations by the Politano-Leadbetter method and 100 by the Cohen tech nique. Brit. J. Urol., 54: 230, 1982. 6. Ehrlich, R. M.: Success of the transvesical advancement technique for vesicoureteral reflux. J. Urol., 1 2 8 : 554, 1982. 7. Burbige, K. A.: Ureteral reimplantation: a comparison of results with the cross-trigonal and Politano-Leadbetter techniques in 120 patients. J. Urol., 1 4 6 : 1352, 199 1 . 8. Majd, M . , Kass, E. J. and Gainey, M. A.: Diuretic augmented radionuclide renography in the evaluation of hydronephrosis in children. J. Nucl. Med., 2 3 : 14, 1982. 9. Peters, C. A., Mandell, J., Lebowitz, R. L., Colodny, A. H., Bauer, S. B., Hendren, W. H. and Retik, A. B . : Congenital obstructed megaureters in early infancy: diagnosis and treatment. J. Urol., part 2, 142: 641, 1989. 10. Skoog, S. J., Belman, A. B . and Majd, M.: A nonsurgical approach to the management of primary vesicoureteral reflux. J. Urol., part 2, 138: 941, 1987.
Vol. 150, 1460-1462, November 1993 Printed in U. S.A.
URETERAL REIMPLANTATION IN INFANTS SAUL P. GREENFIELD , JOHN J. GRISWOLD AND JULIAN WAN From the Department of Urology, Children's Hospital of Buffalo, State University of New York, Buffalo, New York
ABSTRACT
Between 1984 and 1990, 30 infants (46 ureters) 8 weeks to 6 months old (mean age 4 months) underwent ureteral reimplantation. Weight at operation ranged from 4.9 to 9.5 kg. (mean 6.9) . Underlying abnormalities were primary vesicoureteral reflux (28 ureters) , primary ureterovesical junction obstruction ( 1 1 ) , ectopic ureterocele (4) and ectopic ureter (3) . Patients with reflux underwent surgery because of high grade reflux (grade IV or V) or breakthrough infection. Infants with primary ureterovesical junction obstruction underwent obstructive diethylenetriaminepenta acetic acid diuretic renograms. Reimplantations performed included 44 Glenn-Anderson advance ments, 1 Cohen cross-trigonal advancement and 1 Politano-Leadbetter procedure. Of the ureters 30 (65 % ) were tapered intravesically. Ureteral stents were used in all instances. Transient ureteral obstruction developed in 2 children following stent removal and 1 required temporary percutaneous nephrostomy drainage. No permanent ureterovesical obstruction was noted in any patient. Followup at 18 months revealed no postoperative reflux in 43 of 46 ureters (93 % ) . One infant required repeat reimplantation to correct a vesicoureteral fistula and the remaining 2 patients ( 2 ureters) with l o w grade reflux (grade I and II) are being observed. Surgery was successful i n 2 7 of 30 tapered ureters (90 % ) and in all 1 6 of the nontapered ureters ( 100 % ) . While the majority of infants with ureterovesical junction abnormalities may be observed, some may require surgery. Reimplantation, when necessary in this age group, can be performed with a high degree of success and diverting procedures such as vesicostomy or ureterostomy can be avoided. KEY WORDS: infant, vesico-ureteral reflux, ureteral obstruction
The advent of prenatal and early postnatal ultrasound screening has identified more infants with congenital hydro nephrotic conditions. 1-3 Specifically, abnormalities of the ure terovesical junction, including primary vesicoureteral reflux, ureterovesical junction obstruction, ectopic ureter and dupli cation anomalies, are being diagnosed with much greater fre quency within the first few months of life. The natural history of many of these early diagnosed conditions is unknown. Many, if not most, of these infants can be managed nonoperatively, since spontaneous improve ment and resolution of these abnor malities may occur with time. 1 • 4 However, some infants with uncontrollable infections, high grade vesicoureteral reflux or ureterovesical obstruction may benefit from surgical interven tion. Others with static anatomical abnormalities that will not resolve with time, such as ectopic ureters or ureteroceles with functioning renal moieties , may also require reimplantation. Success rates in older children of greater than 95 % with a variety of antireflux procedures are well documented. 5 - 7 There fore, we present a group of infants with a variety of underlying abnormalities who underwent early reimplantation and com pare the outcome with that in older patients. MATERIALS AND METHO D S
Between 1984 and 1990, 18 male and 12 female infants ( 46 ureters) less than 6 months old (range 8 weeks to 6 months, mean age 4 months) underwent ureteral reimplantation. There were 6 infants 8 weeks to 3 months old, 9 infants 3 to 4 months old, 9 infants 4 to 5 months old and 6 infants 5 to 6 months old. A unilateral operation was done in 15 infants, bilateral procedures were done in 13 and reimplantation was performed in 2 with a solitary functioning renal unit. Three reimplanta tions were performed upon complete ureteral duplications. Weight at operation ranged from 4.9 to 9.5 kg. (mean 6.9). A total of 10 infants (33 % ) presented with febrile urinary tract infections, 9 (30%) had hydronephrosis discovered by maternal prenatal ultrasound and 8 (26%) were identified by
early postnatal screening ultrasonography. Two other infants ( 7 % ) were discovered incidentally during cardiac catheteriza tion (1) and a radionuclide bone scan ( 1 ) . One infant (3%) was investigated for a palpable abdominal mass. All patients underwent abdominal ultrasonography and con trast voiding cystourethrography. Upper tract contrast medium or radionuclide imaging was delayed until age 1 month. Upper tract images obtained included excretory urography (IVP) in 28 patients, 99mtechnetium ( 99mTc)-dimercaptosuccinic acid renal scan in 8 and 99mTc-glucoheptonate renal scan in 12. In addition, 99 mTc-diethylenetriaminepentacetic acid (DTPA) renal scans with furosemide were performed in 14 infants suspected of having obstruction, defined as an emptying half time of greater than 20 minutes. 8 The most common diagnosis was vesicoureteral reflux (28 ureters) . All ureters showed high grade reflux (grade IV or V) except for 3 (grade II or III) in patients with high grade contralateral reflux. Ureterovesical junction obstruction was present in 1 1 ureters, ureteral ectopia in 3 and an ectopic ureterocele with an adequately functioning upper pole segment in 4 (see table) . Contralateral ureters without reflux or obstruc tion were not reimplanted. Five infants ( 1 7 % ) had break through urinary tract infections while on prophylactic anti biotics and 4 of those required hospitalization for treatment of urosepsis preoperatively. Reimplantation was done by the Glenn-Anderson advance ment technique in 44 ureters (28 patients) , the Cohen cross trigonal advancement ( 1 ) and the Politano-Leadbetter proce dure ( 1 ) . Greatly dilated ureters were treated with excisional
Accepted for publication April 30, 1993. 1460
Diagnosis of reimplanted ureter Diagnosis
No. Pts.
No. Ureters ( % )
Vesicoureteral reflux U reterovesical junction obstruction Ectopic ureter Ectopic ureterocele Totals
16 9 3 2 30
28 (61) 1 1 (24) 3 (7) ..!_Jfil 46 ( 100)
1461
URETERAL R.EIMPLANTATIO N IN INFANTS
tapering of the intravesical segment. Nontapered ureters were stented with an infant feeding tube (3F or 5F) for 6 days and tapered ureters for 9. The bladder was drained in all patients with a suprapubic catheter, which was removed 1 day after removal of the stents. Hospitalization ranged from 6 to 11 days (mean 8.2) for nontapered reimplantations and 9 to 26 days (mean 11.6) for tapered reimplantations. Followup ranged from 1.5 to 6.5 years (mean 3 . 1). Postoper ative surveillance consisted of urine cultures, contrast voiding cystourethrograms and IVPs at 6 months and 18 months post operatively. Diuretic (furosemide) DTPA renal scans were per formed in all patients postoperatively who had undergone sur gery for ureterovesical junction obstruction and whose prior scans showed obstruction. RESULTS
Two infants who had undergone ureteral reimplantation with tapering had in-hospital complications (transient ureteral ob struction immediately after stent removal). One infant im proved with hydration alone, while 1 required temporary per cutaneous nephrostomy drainage. Postoperative upper tract imaging revealed stable or improved drainage in all instances. All postoperative DTPA scans revealed nonobstructive wash out curves in patients who underwent surgery for primary obstruction. Followup voiding cystourethrograms at 6 months revealed no evidence of reflux in 39 ureters (85%) and persistent reflux in 7, all grade I or II. Radiographic studies were repeated in all infants at 18 months. In 2 infants the reflux resolved sponta neously and 1 with persistent reflux into 2 ureters underwent cystoscopic lysis of intravesical bands with subsequent resolu tion. Presently, 2 patients are being followed with persistent low grade (grades I and II) reflux. Both had undergone ureteral tapering for primary obstructive megaureter: 1 bilaterally (age 8 weeks) and 1 unilaterally (age 4 months). One patient required repeat reimplantation (3 % ) for correction of a vesicoureteral fistula after tapered bilateral reimplantation for high grade reflux at age 4 months. No patients who had undergone reim plantation without tapering had postoperative reflux. An ex ample is provided in figures 1 and 2. Finally, 5 of the 15 infants (33 % ) who underwent unilateral reimplantation had new low grade (grade I or II) contralateral reflux and they are all being observed. Overall, a successful outcome was achieved in 43 of 46 ureters reimplanted (93 %) or 27 of 30 patients (90 %). Surgery was successful in 27 of 30 tapered reimplantations (90%) and in all 16 nontapered reim plantations (100% ).
FIG. 2. IVP at age 2 years. Bilateral reimplantation was performed at age 8 weeks. DTPA renal scans with furosemide confirmed absence of residual obstruction. DISCUSSION
The widespread screening of fetuses with prenatal ultrasound has markedly increased the number of newborns being iden tified with hydronephrotic conditions. A significant number of these infants will ultimately have abnormalities of the ureterovesical junction. Of 187 neonatal hydronephrotic units identified prenatally by Homsy et al 13.4% and 9. 1 % had ureterovesical junction obstruction and vesicoureteral reflux, respectively.'3 Recent series on infants with primary obstructive megaureters report that 52 to 72% of the cases were discovered prenatally. 4 ' 9 Infants with prenatally diagnosed vesicoureteral reflux differ from older presenting children in that they have higher grades of reflux (65% grades IV or V) and male infants predominate (84 to 91%). 1 ' By contrast, in a review of 545 children of all ages with reflux, grade IV or V reflux was noted in 7.6% and only 15% were boys. 1 0 There is controversy surrounding the management of these newborns. Keating et al reported that 20 of 23 primary obstruc tive megaureters diagnosed prenatally (87%) were managed nonoperatively and renal function did not deteriorate. 4 Con versely, Peters et al reported on the successful outcome in infants less than 8 months old who underwent ureteral reim plantation for primary ureterovesical junction obstruction, sug gesting the necessity for early surgery. 9 The natural history over a long period of massively dilated refluxing ureters diag nosed prenatally or early in infancy is unknown. However, Gordon et al suggested that these infants may be managed expectantly, since spontaneous resolution is possible. 1 They observed cessation of reflux in 35% of the ureters followed for a mean of 2. 1 years and effective antibiotic prophylaxis in 80% of the patients followed. This is in contradistinction to findings in studies of older children, which showed that grade IV or V reflux rarely resolves spontaneously. 10 Therefore, the role of early surgery is an unresolved issue 2
FIG. 1. Percutaneous nephrostograms show high grade bilateral ure terovesical junction obstruction in newborn diagnosed prenatally. Note that no contrast medium enters bladder. Antenatal ultrasound had shown bilateral hydroureteronephrosis and oligohydramnios. A, right side. B, left side.
1462
URETERAL REIMPLANTATION IN INFANTS
and remains controversial. While many infants with congenital abnormalities of the ureterovesical junction may be managed nonoperatively, some may require surgery because of uncon trollable urinary tract infections or high grade obstruction. In addition, in a number of infants with massively dilated ureters secondary to vesicoureteral reflux the reflux will never resolve. Others with ectopic ureters and ureteroceles with well function ing renal moieties will require definitive correction, since spon taneous resolution will not occur. Our success rates of 100% in nontapered reimplants and 90% in tapered reimplants compare favorably with previous operative rates of success in older children. One need not delay an operation or propose temporary diverting procedures, such as vesicostomy or ureterostomy, if reimplantation is necessary or ultimately will be required. REFERENCES
1. Gordon, A. C., Thomas, D. F., Arthur, R. J., Irving, H. C. and Smith, S. E.: Prenatally diagnosed reflux: a follow-up study. Brit. J. Urol., 65: 407, 1990. 2. Anderson, P. A. M. and Rickwood, A. M. K.: Features of primary vesicoureteric reflux detected by prenatal sonography. Brit. J. Urol., 67: 267, 1991.
3. Homsy, Y. L., Saad, F., Laberge, I., Williot, P . and Pison, C.: Transitional hydronephrosis of the newborn and infant. J. Urol., part 2, 144: 579, 1990. 4. Keating, M. A., Escala, J., Snyder, H. McC., III, Heyman, S. and Duckett, J. W.: Changing concepts in management of primary obstructive megaureter. J. Urol., part 2, 142: 636, 1989. 5. Carpentier, P. J., Bettink, P. J., Hop, W. C. J. and Schroder, F. H.: Reflux-a retrospective study of 100 ureteric reimplantations by the Politano-Leadbetter method and 100 by the Cohen tech nique. Brit. J. Urol., 54: 230, 1982. 6. Ehrlich, R. M.: Success of the transvesical advancement technique for vesicoureteral reflux. J. Urol., 1 2 8 : 554, 1982. 7. Burbige, K. A.: Ureteral reimplantation: a comparison of results with the cross-trigonal and Politano-Leadbetter techniques in 120 patients. J. Urol., 1 4 6 : 1352, 199 1 . 8. Majd, M . , Kass, E. J. and Gainey, M. A.: Diuretic augmented radionuclide renography in the evaluation of hydronephrosis in children. J. Nucl. Med., 2 3 : 14, 1982. 9. Peters, C. A., Mandell, J., Lebowitz, R. L., Colodny, A. H., Bauer, S. B., Hendren, W. H. and Retik, A. B . : Congenital obstructed megaureters in early infancy: diagnosis and treatment. J. Urol., part 2, 142: 641, 1989. 10. Skoog, S. J., Belman, A. B . and Majd, M.: A nonsurgical approach to the management of primary vesicoureteral reflux. J. Urol., part 2, 138: 941, 1987.