Result of Endoureterotomy in the Management of Primary Obstructive Megaureter in the First Year of Life: Preliminary Report

Abstract

Purpose:

The present study aimed to investigate the efficacy of endoureterotomy in patients who were less than 1-year-old with primary obstructive megaureter (POMU).

Patients and Methods:

Three of 10 patients with POMU aged between 2 and 12 months for whom conservative management was not applicable had recurrent urinary tract infection (UTI) and urosepsis, while the rest had decreased renal function. After obtaining the clinical history and performing physical examinations and imaging studies (ultrasonography, voiding cystourethrography (VCUG), radionuclide renal scan), the patients underwent endoureterotomy using a neonatal ureteroscope (4.5F) and Bugbee electrode with pure cutting current at the 6 o'clock position. A Double-J stent was inserted and removed 1 week later. This was followed by serial physical examination, renal function test, urine analysis, urine culture, and imaging studies in the 1st month and every 3 months after Double-J stent removal.

Results:

Hydroureteronephrosis was significantly decreased in nine patients. Postoperative VCUG revealed no sign of iatrogenic vesicoureteral reflux. In addition, a follow-up renal scan showed remarkable improvement in the renal function in the patients who had decreased renal function, except for one patient in whom uncontrolled urosepsis developed in the follow-up; the patient underwent cutaneous ureterostomy. No UTI was detected in the group who presented with recurrent UTI and urosepsis.

Conclusion:

According to the results of our study, endoureterotomy may be an alternative in management of POMU. Of course, further studies with longer follow-up periods are needed to confirm the applicability of this method in patients younger than 1 year.

Introduction

Ureteral diameter more than 5 mm in association with a group of anomalies is labeled as megaureter.^1,2 Several hypotheses have been made concerning the pathophysiology of primary obstructive megaureter (POMU), such as alteration in the muscularis layers of the distal part of the ureter by absent longitudinal muscle fiber and hypertrophied circular muscle or increase in the connective tissue deposition.^3,4 Males are more commonly involved, with dominancy at the left side.⁵ Patients with POMU may present with variable symptoms, such as urinary tract infection (UTI), urosepsis, failure to thrive, and abdominal mass. Multiple management strategies are available for children less than 1 year old, and the therapeutic modality is quite difficult to select. In patients with mild obstruction, conservative management by symptoms monitoring, periodic radiologic imaging study, and prophylactic antibiotic therapy is an acceptable modality.^6

–9 On the other hand, progressive renal damage is an indication for operative management, regardless of the patient's age.^10
–12

The ultimate goal of surgical intervention is preserving renal function and its development by relieving the obstruction of the collecting system without creation of iatrogenic reflux. To date, ureteroneocystostomy is an acceptable open surgical intervention for correction of obstructing megaureter in symptomatic patients. It has its own complications, however, especially when a dilated ureter is reimplanted into the small bladder, which may interfere with the functional development of the lower urinary tract because the trigone will be manipulated. It may create iatrogenic vesicoureteral reflux (VUR), as well.^12,13 Reimplantation of an obstructed megaureter should be avoided in the first year of life. because it has a higher failure rate as well as a greater risk of morbidity and reoperation.^10,14 Some researchers have recommended cutaneous ureterostomy^15,16 or temporary Double-J stent insertion¹⁷ to preserve the function of the kidney. These procedures have several complications, however, including encrustation, stent migration, UTI, stone formation, and stomal stenosis.^18
–20

In this study, we aim to report our preliminary experience of endoureterotomy for treatment of primary obstructed megaureter in children less than 1 year old.

Patients and Methods

The present study was performed between January 2010 and January 2011, and the patients were followed by serial physical examination, renal function test, urine analysis, urine culture, and imaging studies in the 1st month and every 3 months after Double-J stent removal. The study was conducted in 10 patients younger than 1 year who were selected from different centers. The patients were followed up in different manners regarding the timing of renal isotope scan and ultrasonography in the conservative management period. All the enrolled patients with impaired renal function had below 40% differential functions on the last preoperative isotope scan. All patients underwent renal ultrasonography, revealing a ureteral diameter of more than 15 mm. Moreover, voiding cystourethrography (VCUG) and diuretic renography were performed for all the patients to select those without reflux and obtain their baseline renal function. After confirming the diagnosis, urine analysis and urine culture were obtained and then prophylactic antibiotics were started.

Our inclusion criteria for surgical intervention were impaired differential function on the last preoperative assessment (differential function less than 40%), distal ureteral diameter more than 15 mm at ultrasonography, and recurrent UTI after a period of antibiotic prophylaxis or urosepsis. Based on the inclusion criteria, the patients were classified into two groups: (1) patients with decreased renal function, and (2) patients who presented with recurrent UTI or urosepsis (cases 5, 6, and 8) with acceptable renal function on the last preoperative renal scan (more than 40%).

The study and the procedure were reviewed and approved by the research and ethics committee of Shiraz University of Medical Sciences, Shiraz, Iran. All the patients' legal guardians were informed about the options that existed for management of this problem and informed consents for taking part in the study were obtained from them. Our procedure was started under general anesthesia. Before endoureterotomy, cystoscopy was performed to rule out posterior urethral valve and ectopic ureter. Then, a 0.018-inch guidewire was applied to access the affected ureter by ureteroscope (4.5F neonatal ureteroscope [Richard Wolf GmbH, Knittlingen, Germany]). In stenotic cases in which the ureteroscope was not advanced through the ureterovesical junction (UVJ), a zebra guidewire was used along with the safety guidewire to bypass it using a railroad maneuver. After passing through the UVJ, there was a stenotic ring a few millimeters behind the UVJ. After insertion of the safety wire and passing it through the stenotic ring, a retrograde incision was made at the 6 o'clock position longitudinally using a Bugbee electrode with pure cutting current (25W). The ureteroscope was advanced simultaneously when we made the incision. The stenotic ring was passed by the ureteroscope, and the adequacy and depth of the incision were rechecked while we were pulling off the ureteroscope from the ureter. After completion of the procedure, a 3F Double-J stent was inserted into the affected ureter. The stent was removed 1 week after the procedure, and antibiotic therapy (first generation cephalosporin) was continued during this time.

The patients were followed up for about 18 months, and urine culture and serial ultrasonography were obtained at the first month and every 3 months after ureteral stent removal. In addition, VCUG was performed at the sixth month of the follow-up to rule out iatrogenic VUR. Moreover, a radionuclide renal scan was obtained from the patients at 3, 6, and 18 months of the follow-up period. In this study, the operative goals were defined as reduction in the degree of hydroureteronephrosis, improvement in or stabilization of renal function, and elimination of the UTI episodes.

Results

The present study was conducted in 10 patients (7 boys and 3 girls) aged between 2 months and 12 months (mean 7.1 mos). The mean follow-up period was 18 months (range 6–24 mos). Left-side involvement was detected in all the patients, except for one whose problem was at the right side. Also, seven patients presented with decreased renal function (group 1), while three (group 2) were referred with recurrent UTI and urosepsis that was unresponsive to prophylactic antibiotic therapy. One of the patients was febrile because of UTI. In addition, four of the seven male patients were circumcised when they were referred to us.

The endoureterotomy procedure lasted for 25 up to 40 minutes. No significant intraoperative or postoperative complications were notable. The hospitalization time was 24 to 48 hours. At the 18th month of the follow-up, 6 of the 10 patients had complete resolution in the degree of hydroureteronephrosis (Fig. 1), and 3 patients showed reduction from severe to mild (Table 1). Except for one (case 9), all the patients in group 1 (cases No. 1, 2, 3, 4, 7, 9, and 10) showed significant improvement in renal function postoperatively. Although the degree of hydronephrosis in case 9 diminished from severe to moderate, urosepsis developed in that patient during the period of follow-up visits with reduction in kidney function on renal isotope scan; therefore, loop cutaneous ureterostomy was performed for this patient.

FIG. 1.

(A) Preoperation ultrasongraphy and (B) postoperative ultrasonography. BL=bladder; LU=left ureter; UBL=urinary bladder.

Table 1.

Characteristics of Patients at 6 and 18 Months of Follow-Up

			Creatinine			DTPA scan			Distal ureteral diameter (mm)			Degree of hydroureteronephrosis
No.	Sex	Age (mos)		Postop			Postop			Postop			Postop
			Preop	6	18	Preop	6	18	Preop	6	18	Preop	6	18
1	M	2	0.4	0.2	0.3	25% Lt	36% Lt	49% Lt	25	14	5	Severe	No	No
2	M	6	0.5	0.4	0.5	35% Lt	42% Lt	45%Lt	16	10	4	Moderate	No	No
3	M	12	0.5	0.6	0.5	29% Lt	40% Lt	40% Lt	25	14	8	Severe	Mild	Mild
4	M	7	0.4	0.4	0.4	9.2% Lt	32% Lt	37% Lt	17	10	3	Severe	No	No
5	M	8	0.4	0.5	0.5	50% Rt	48% Rt	49% Rt	20	14	7	Severe	Mild	Mild
6	F	5	0.6	0.4	0.5	50% Lt	50% Lt	49% Lt	22	20	11	Severe	Mild	Mild
7	M	9	0.5	0.5	0.5	29% Lt	49% Lt	48% Lt	21	14	5	Severe	No	No
8	F	5	0.5	0.4	0.4	45% Lt	47% Lt	45% Lt	25	14	8	Severe	No	No
^*9	F	6	0.5	0.5	0.4	10.5% Lt	8% Lt	—	18	12	—	Severe	Moderate	—
10	M	11	0.7	0.5	0.4	24% Lt	41% Lt	45% Lt	22	12	5	Severe	No	No

Case 9 was not included at 18 months of follow-up because of urosepsis and deteriorated renal function; she underwent cutaneous ureterostomy at 12 months of age.

All patients had no vesicoureteral reflux on preoperative and postoperative voiding cystourethrography.

Cases 5 and 6 presented with recurrent urinary tract infection, case 8 presented with urosepsis, and all others had decreased renal function.

DTPA=diethylenetriaminepentaacetic acid; preop=preoperative; postop=postoperative.

In group 2 (cases No. 5, 6, and 8), although renal function had not changed significantly, all the patients were infection free postoperatively, and distal ureteral diameters were decreased.

Discussion

POMU refers to the condition in which the patient presents with intrinsic ureteral obstruction in the distal end of the ureter. This condition can be explained by various pathophysiologic causes, including ureteral muscularis layer involvement by diminished longitudinal fibers and hypertrophic change of circular muscle fibers,⁴ changes in the innervation pattern of the muscularis layer,²¹ and deposition of collagen material in the abnormal matter.³ According to several pathophysiologic issues existing in the background of this condition, various treatment options are advised for management of POMU. In spite of these several methods of treatment, the management of this condition remains inconclusive, especially in children less than 1 year old.

Nonoperative conservative treatment was investigated by some researchers but had a failure rate of about 84%.²² In other studies, spontaneous resolution of POMU without impairment in the renal function was reported.^6,23

–26 POMU in association with progressive renal damage, symptoms such as fever and flank pain, and increasing dilatation, is indicated for operative management. Arena and coworkers³⁰ reported that hydroureteronephrosis resolved spontaneously in 55.6% of their patients when the retrovesical ureteral diameter was between 11 and 15 mm.²⁷ They also mentioned that spontaneous resolution was less likely when ureteral diameter was more than 15 mm.

Peters and colleagues¹⁰ conducted a study in which 89% of the patients were less than 8 months old and reported a remarkable reoperation rate. Similar to the plication method or excisional tapering technique, open surgery has its own complications, the most common of which being ureteral stricture.²⁸ In addition, an open surgical procedure is associated with technical difficulties regarding reimplantation of the dilated ureter into a small bladder. Consequently, some researchers have recommended cutaneous ureterostomy^15,16 or temporary Double-J stent insertion.¹⁷ Cutaneous ureterostomy is associated with many complications, such as ischemia of the distal ureter, stomal stenosis, and difficulty in other future surgeries.^19,20 Temporary Double-J stent placement is also accompanied by several complications, including stent migration, encrustation, UTI, and stone formation.¹⁸ Bladder dysfunction is another complication of open surgery in this age group.^14,29

The need for intervention for the aforementioned group and the remarkable complications of the open surgical techniques have led to emergence of minimally invasive methods that preserve renal function with acceptable postoperative results and minimal postoperative complications. There is a paucity of data, however, regarding the endoscopic management of POMU in the literature.

Yttrium-aluminum-garnet (YAG) laser endoureterotomy has also been described in the literature. This technique was used for ureteral stricture in two studies, one of which reported an acceptable success rate,³⁰ while the other reported a lower one.³¹ YAG laser was also used for correction of congenital megaureter in adults with symptomatic and radiologic improvement of all patients at 30.5 months.³²

Endoscopic balloon dilation is suggested by some clinicians as a minimally invasive therapy in patients less than 1 year old who have POMU.^13,33 This procedure, however, is not without its complications. As Garcia-Aparicio and associates³³ pointed out, 3 of 13 patients needed ureteral reimplantation because of persistent hydroureteronephrosis and VUR. Furthermore, the balloon is not available worldwide, and there is limited experience with this technique. Kajbafzadeh and colleagues¹² demonstrated the long-term safety of endoureterotomy in patients more than 1 year old.

Endoscopic ureteral incision for POMU in children more than 1 year old was first described by Kajbafzadeh and coworkers¹² with a postoperative success rate of about 90%.

The high rate of postoperative open surgery morbidity, creation of VUR, and its cost are diminished when using the endoscopic approach. The endoscopic technique also prevents damage to the vasculature of the distal end of the ureter. As reported by Defoor and associates,³⁴ open surgery would compromise it and result in ureteral stricture in the future.

In practice, an endoscopic ureteral incision could be made by several methods, such as cold knife, electrosurgical probes, and the holmium:YAG laser. In the present study, the researchers made use of the electrocautery method, because it provides precise control of the incision width and length with good ability to provide local hemostasis.¹²

A Double-J stent was inserted for all the patients for 1 week after the operation to promote ureteral healing. It may prevent restricturing or urine extravasation, as well. On the other hand, long-lasting ureteral stent placement can cause inflammation, leading to impairment in the healing process as well as scar tissue formation.³⁵

Kajbafzadeh and coworkers¹² performed endoureterotomy after at least 12 months of conservative management. In our study, all patients underwent endoureterotomy when they were less than 1 year old.

We used a Double-J stent for 1 week to reduce the risk of restricturing. The diameter of the distal ureteral part and the kidney function were improved in all the study patients, except for one who underwent cutaneous ureterostomy because of deterioration in her renal function and urosepsis in the follow-up (case 9). No new onset of UTI was observed in our patients postoperatively, however. The prophylactic antibiotic was discontinued after performing the renal scan to confirm obstruction resolution. Overall, the results of the current study suggest that endoureterotomy is practicable for children less than 1 year old with POMU. Of course, further studies with longer follow-up periods are needed on a larger number of patients to confirm the obtained results.

Conclusion

In this study, we tried a new method for management of POMU in patients less than 1 year old. There is controversy in the management of this problem. Minimally invasive procedures result in a high success rate and are not accompanied by the complications associated with other methods, especially conventional open surgery. The findings of the present study revealed a remarkable success rate in patients undergoing endoureterotomy. According to the preliminary results of our study, endoureterotomy may be an alternative in management of POMU. Of course, further studies with longer follow-up periods are needed to confirm the applicability of this method in patients less than 1 year old.

Footnotes

Acknowledgments

The present article was extracted from the thesis written by Mr. Mohammad Natami in Urology approved by Shiraz University of Medical Sciences (Proposal No. 90-01-01-4087).

The authors would like to thank the Research Improvement Center of Shiraz University of Medical Sciences, Shiraz, Iran, and Ms. A. Keivanshekouh for improving the use of English in the manuscript.

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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