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Obstructed Megaureter Treatment & Management

  • Author: Robert A Mevorach, MD; Chief Editor: Edward David Kim, MD, FACS  more...
Updated: May 22, 2013

Medical Therapy

In mild cases of obstructed megaureter, physicians may monitor symptoms, perform periodic radiological imaging, and administer antibiotic prophylaxis. With improving or stable renal or ureteral dilatation and continued renal growth, prognosis (over 8 y of follow-up) is excellent.


Surgical Therapy

Megaureters detected in neonates and infants may require drainage for infections that do not respond to antibiotics alone. Additionally, the massively dilated ureter may be decompressed with ureterostomy, refluxing ureteroneocystostomy, pyelostomy, or nephrostomy drainage, which often allows a substantial decrease in ureteral size and greatly reduces ureteral bulk during both tailoring and reimplantation.

The ultimate goals of surgical intervention are to relieve obstruction, to return near-normal function to the collecting system, to create a nonrefluxing vesicoureteral reimplantation, and to preserve renal development without long-term complications. With these goals, the two main surgical approaches are as follows:

  • Distal ureteral mobilization with resection of the obstructing segment and reimplantation, with or without ureteral tailoring (to ensure a nonrefluxing tunnel)
  • Extensive tailoring of the ureter from the renal pelvis distally to provide a theoretical benefit for restoring normal peristalsis by reduction of ureteral luminal diameter

In experienced hands, both approaches yield excellent long-term results. Substantive differences are not statistically or clinically apparent.

Patients with voiding dysfunction or significant reflux may benefit from an intravesical ureteral reimplantation. Patients without voiding problems or reflux do equally well from an extravesical approach.

Primary endoureterotomy with stenting has been reported favorably in selected cases in children. In one series, 90% of cases showed improvement, with complete resolution reported in 71%.[5]

In adults, a direct nipple ureteroneocystostomy can be performed. This is technically simpler to perform since the ureters and submucosal tunnels require no tailoring. Limited reports with follow-up of up to 36 months indicate a high success rate with this technique in adults.[6]


Preoperative Details

Document that patients are free of infection at the time of reconstruction. Blood loss is normally insubstantial, and transfusion is rarely necessary.


Intraoperative Details

The incision is chosen to access the upper ureter, the lower ureter, or the entire ureter. Use intravesical and extravesical dissection, alone or in combination, to mobilize the enlarged ureter.

Take care to preserve the ureteral blood supply, which arises from the aorta, renal artery, gonadal artery, and internal iliac artery, particularly if undertaking extensive tailoring.

Tailoring either can be excisional or can involve varied forms of luminal exclusion and ureteral folding; however, reductions smaller than 10F are not recommended to avoid subsequent stenosis.

Neocystostomy tunnel lengths of 4:1-6:1 are recommended to avert postoperative reflux. Postoperative drains or splints for the ureters are used at the discretion of the surgeon.


Postoperative Details

Patients remain on antibiotic prophylaxis for months after surgery, until imaging studies or clinical status warrants discontinuation.



Repeated ultrasonography imaging is mandatory to assess whether hydronephrosis and hydroureter improve after surgery. Because the benefit of repeat VCUG and IVU studies is controversial, in the setting of clinical success and ultrasonography improvement, the only recommendation is that the patient and physician agree on the follow-up regimen.



Surgical complications are uncommon and often resolve with observation.

  • Ipsilateral reflux occurs in 2% of patients. Endoscopic ureteral bulking permits a less-invasive management of this complication when the clinical scenario warrants, and it may all but eliminate open reoperation.
  • Contralateral reflux occurs in 10% of patients but resolves within 1 year in nearly all cases.
  • Ureteral obstruction (1%): Early balloon dilation or incision of the meatal stenosis (3 mo) is highly successful. Strongly consider ureteral stenosis of 1.5 cm or greater and devascularized ureteral segments for open reoperation.
  • Incomplete bladder emptying requiring catheterization (5%): Permanent retention is not reported.

Outcome and Prognosis

Researchers report that surgical outcomes are 98% successful in all major series. Failures were usually in the form of reflux and often occurred with nontapered reimplants. Reoperation with tailoring and repeat neocystostomy is uniformly corrective.

Children who present with infection may experience persistent episodes of UTI. Consider these patients for prolonged prophylaxis to limit the impact of infection on renal growth. Additionally, emphasize UTI surveillance during pregnancy.

Renal function is the key determinant of prognosis because renal dysplasia and infection with associated renal insufficiency are the only expected long-term disabilities associated with primary obstructed megaureter.


Future and Controversies

As with all reconstructive procedures, the belief that recapitulation of anatomy is necessary to achieve excellent functional results is tested continually by the desire to minimize the extent and duration of surgical invasion. When patients are well-served, finding fault with either approach is difficult.

The next wave of interest will arise from the growing trend toward minimally invasive surgery and the application of improved laparoscopic and robotic techniques to reconstructive pediatric urology.

Contributor Information and Disclosures

Robert A Mevorach, MD Associate Professor, Departments of Urology and Pediatrics, University of Rochester School of Medicine

Robert A Mevorach, MD is a member of the following medical societies: American Academy of Pediatrics, American Urological Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Edward David Kim, MD, FACS Professor of Surgery, Division of Urology, University of Tennessee Graduate School of Medicine; Consulting Staff, University of Tennessee Medical Center

Edward David Kim, MD, FACS is a member of the following medical societies: American College of Surgeons, Tennessee Medical Association, Sexual Medicine Society of North America, American Society for Reproductive Medicine, American Society of Andrology, American Urological Association

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Repros.

Additional Contributors

Bradley Fields Schwartz, DO, FACS Professor of Urology, Director, Center for Laparoscopy and Endourology, Department of Surgery, Southern Illinois University School of Medicine

Bradley Fields Schwartz, DO, FACS is a member of the following medical societies: American College of Surgeons, Society of Laparoendoscopic Surgeons, Society of University Urologists, Association of Military Osteopathic Physicians and Surgeons, American Urological Association, Endourological Society

Disclosure: Nothing to disclose.

  1. Hendren WH, Henderson BM. Recent advances in pediatric surgery. Am J Surg. 1969 Sep. 118(3):338-55. [Medline].

  2. Creevy CD. The atonic distal ureteral segment (ureteral achalasia). J Urol. 1967 Mar. 97(3):457-63. [Medline].

  3. Williams DI, Hulme-Moir I. Primary obstructive mega-ureter. Br J Urol. 1970 Apr. 42(2):140-9. [Medline].

  4. Mortell A, Fourcade L, Solari V, Puri P. Bilateral megaureters in the Adriamycin rat model. Pediatr Surg Int. 2005 Mar. 21(3):212-6. [Medline].

  5. Kajbafzadeh AM, Payabvash S, Salmasi AH, Arshadi H, Hashemi SM, Arabian S, et al. Endoureterotomy for treatment of primary obstructive megaureter in children. J Endourol. 2007 Jul. 21(7):743-9. [Medline].

  6. Tatlisen A, Ekmekçioglu O. Direct nipple ureteroneocystostomy in adults with primary obstructed megaureter. J Urol. 2005 Mar. 173(3):877-80. [Medline].

  7. Arena F, Baldari S, Proietto F, Centorrino A, Scalfari G, Romeo G. Conservative treatment in primary neonatal megaureter. Eur J Pediatr Surg. 1998 Dec. 8(6):347-51. [Medline].

  8. Bakker HH, Scholtmeijer RJ, Klopper PJ. Comparison of 2 different tapering techniques in megaureters. J Urol. 1988 Nov. 140(5 Pt 2):1237-9. [Medline].

  9. Bapat S, Bapat M, Kirpekar D. Endoureterotomy for congenital primary obstructive megaureter: preliminary report. J Endourol. 2000 Apr. 14(3):263-7. [Medline].

  10. Belman AB. Megaureter. Classification, etiology, and management. Urol Clin North Am. 1974 Oct. 1(3):497-513. [Medline].

  11. DeFoor W, Minevich E, Reddy P, Polsky E, McGregor A, Wacksman J, et al. Results of tapered ureteral reimplantation for primary megaureter: extravesical versus intravesical approach. J Urol. 2004 Oct. 172(4 Pt 2):1640-3; discussion 1643. [Medline].

  12. Erbas B, Royal SA, Joseph D. Scintigraphic evaluation of obstructing primary megaureter with Tc-99m MAG3. Clin Nucl Med. 1997 Jun. 22(6):355-8. [Medline].

  13. Lee SD, Akbal C, Kaefer M. Refluxing ureteral reimplant as temporary treatment of obstructive megaureter in neonate and infant. J Urol. 2005 Apr. 173(4):1357-60; discussion 1360. [Medline].

  14. Lockhart JL, Politano VA. Management of massively dilated ureters in children. Urology. 1981 Sep. 18(3):229-34. [Medline].

  15. McLaughlin AP 3rd, Pfister RC, Leadbetter WF, Salzstein SL, Kessler WO. The pathophysiology of primary megaloureter. J Urol. 1973 May. 109(5):805-11. [Medline].

  16. Patti G, Menghini ML, Todini AR, Marrocco G, Calisti A. The role of the renal resistive index ratio in diagnosing obstruction and in the follow-up of children with unilateral hydronephrosis. BJU Int. 2000 Feb. 85(3):308-12. [Medline].

  17. Payabvash S, Kajbafzadeh AM, Tavangar SM, Monajemzadeh M, Sadeghi Z. Myocyte apoptosis in primary obstructive megaureters: the role of decreased vascular and neural supply. J Urol. 2007 Jul. 178(1):259-64; discussion 264. [Medline].

  18. Rabinowitz R, Barkin M, Schillinger JF, Jeffs RD. Surgical treatment of the massively dilated primary megaureter in children. Br J Urol. 1979 Feb. 51(1):19-23. [Medline].

  19. Rabinowitz R, Barkin M, Schillinger JF, Jeffs RD, Cook GT. Surgical treatment of the massively dilated ureter in children. Part II. Management by primary reconstruction. J Urol. 1977 Sep. 118(3):436-9. [Medline].

  20. Rabinowitz R, Barkin M, Schillinger JF, Jeffs RD, Cook GT. The influence of etiology on the surgical management and prognosis of the massively dilated ureter in children. J Urol. 1978 Jun. 119(6):808-13. [Medline].

  21. Shukla AR, Cooper J, Patel RP, Carr MC, Canning DA, Zderic SA, et al. Prenatally detected primary megaureter: a role for extended followup. J Urol. 2005 Apr. 173(4):1353-6. [Medline].

  22. Stehr M, Metzger R, Schuster T, Porn U, Dietz HG. Management of the primary obstructed megaureter (POM) and indication for operative treatment. Eur J Pediatr Surg. 2002 Feb. 12(1):32-7. [Medline].

  23. Tanagho EA. Embryologic basis for lower ureteral anomalies: a hypothesis. Urology. 1976 May. 7(5):451-64. [Medline].

  24. Thompson A, Gough DC. The use of renal scintigraphy in assessing the potential for recovery in the obstructed renal tract in children. BJU Int. 2001 Jun. 87(9):853-6. [Medline].

This renal sonogram demonstrates hydronephrosis with good parenchymal thickness and retained corticomedullary differentiation.
This pelvic sonogram reveals the classic spindle configuration of primary obstructed megaureter.
This panel from a technetium Tc 99m mercaptotriglycylglycine (MAG-3) renal scan shows differential obstruction of each kidney. While the classic image of a primary obstructed megaureter is shown on the left, a severe congenital ureteropelvic junction obstruction is present in the contralateral kidney. (These images are viewed with the left kidney on the left portion of each panel and the right kidney on the right portion of each panel.)
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