Pediatric Endourology
JOURNAL OF ENDOUROLOGY Volume 00, Number 00, XXXXXX 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2013.0665
Primary Obstructive Megaureter in Infants: Our Experience with Endoscopic Balloon Dilation and Cutting Balloon Ureterotomy Nicola Capozza, MD, Giovanni Torino, MD, PhD, Simona Nappo, MD, Giuseppe Collura, MD, PhD, and Ermelinda Mele, MD
Abstract
The management of primary obstructive megaureter (POM) is usually conservative, at least in the first year of life. Nevertheless, in high-grade POMs with increasing dilation, obstructive patterns found at renography, or cases involving decreased renal function, there is a clear indication for surgery. From January 2009 to March 2013, 12 patients, aged 6 to 12 months (mean 8 months), were treated endoscopically for POM. At the procedure, a clear stenotic ring was identified in 10 of the 12 patients, and a simple endoscopic high-pressure balloon dilation (EHPBD) was well performed in 7 patients. In the three cases with persistent ring, a cutting balloon ureterotomy (CBU) was then performed, resulting in the immediate and complete disappearance of the stenosis. In two cases, no ring could be seen at the procedure, and they showed no improvement at the follow-up. The mean follow-up was 21 months. Considering the whole series of patients treated endoscopically, the overall success rate of EHPBD + CBU was 83%. Patients with POM can be treated endoscopically. In the case of a persistent ring that is unresponsive to EHPBD, CBU seems to provide a valid definitive treatment of POM.
Introduction
Patients and Methods
T
From January 2009 to March 2013, 12 patients, aged 6 to 12 months (mean age 8 months), were treated endoscopically for POM. This series represents about 10% of all nonrefluxing megaureters followed in the same period at our institution. As described in a previous article,14 during this preliminary experience employing endoscopic treatment of POM, all the patients were initially evaluated using renal ultrasound in the first month of life as a follow-up to prenatal hydronephrosis. Renal and urinary tract ultrasound was then repeated every 2 months. Voiding cystourethrogram (VCUG) was performed in all cases. MAG3 renal imaging was performed between 1 and 2 months after birth, with the assessment of differential renal function and isotope washout. In the case of poor urinary drainage at the basal reno/ ureterogram, a diuretic test was performed. Washout halftime (T½) of > 20 minutes was taken as representing an obstruction.15–17 The inclusion criteria for the study were initial dilation of the distal ureter > 15 mm, increasing dilation at follow-up, urinary tract infection (UTI), and obstruction at MAG3 renography.
he management of primary obstructive megaureter (POM) is usually conservative, at least in the first year of life.1–3 Nevertheless, there are certain circumstances, such as high-grade POMs with increasing dilation, obstructive patterns found at renography, or cases involving decreased renal function that do not permit delay, given the risk of permanent renal damage.4,5 Until a few years ago, these cases were managed using temporary urinary diversion (ureterostomy, ureteral stenting),6–11 awaiting definitive surgical repair; this was conventionally indicated after 1 year of age. Recently, endoscopic high-pressure balloon dilation (EHPBD) of the vesicoureteral junction (VUJ) has been proposed as an alternative to surgery in the first year of life.12–14 The results have generally been extremely satisfactory. However, in some cases, the procedure remains only partially well performed despite prolonged dilation. In such cases of stenosis that do not respond to high-pressure dilation, the authors of this work completed the procedure by employing cutting balloon ureterotomy (CBU). We analyzed the outcome of a series of infants with obstructive megaureter, treated endoscopically by balloon dilation and CBU.
Surgical Unit of the Pediatric Urology, ‘‘Bambino Gesu`’’ Children’s Hospital and Research Institute, Rome, Italy.
1
CBU = cutting balloon ureterotomy; DUD = distal ureteral diameter; EHPBD = endoscopic high-pressure balloon dilation; F = female; ID = increasing dilatation; L = left; M = male; Obstruction (O) = T/2 > 20 minutes after diuretic during renography; No obstruction = good urinary drainage out of the ROIs at 30 minutes after injection of the MAG-3 without diuretic test; OPEN = reimplantation with open technique; R = right; UTI = urinary tract infection.
/ CBU / CBU / OPEN
/ OPEN / CBU
EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD No No No No No Yes No No No No Yes No 6 12 6 6 10 9 11 8 9 12 12 6 ID + O ID + O ID + O ID + O UTI + O ID + O ID + O UTI + O UTI + O UTI + O ID + O ID + O M M M M F F M F M M F M
L R L R R L L R L L L L
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
R: R: R: R: R: R: R: R: R: R: R: R:
55%; 44%; 53%; 47%; 51%; 50%; 60%; 49%; 62%; 49%; 53%; 67%;
45%/R: 56%/R: 47%/R: 53%/R: 49%/R: 50%/R: 40%/R: 51%/R: 38%/R: 51%/R: 47%/R: 33%/R: L: L: L: L: L: L: L: L: L: L: L: L: 1 2 3 4 5 6 7 8 9 10 11 12
54%; 45%; 55%; 47%; 55%; 50%; 58%; 51%; 45%; 50%; 54%; 65%;
L: L: L: L: L: L: L: L: L: L: L: L:
46% 55% 45% 53% 45% 50% 42% 49% 55% 50% 46% 35%
22 mm 19 mm 18 mm 19 mm 16 mm 17 mm 22 mm 16 mm 15 mm 16 mm 18 mm 26 mm
Procedures Postoperative Last obstruction preoperative Indication Age at surgery pattern at MAG-3 ultrasound for surgery (months) diuretic renography (DUD) Preoperative/ postoperative split renal function Preoperative obstruction pattern at MAG-3 diuretic Affected renography Patients Sex side
Table 1. Outcomes and Characteristics of the Patients
11 mm at 44 9 mm at 42 3 mm at 38 2 mm at 35 13 mm at 30 16 mm at 18 8 mm at 14 11 mm at 11 9 mm at 9 9 mm at 7 16 mm at 6 15 mm at 2
CAPOZZA ET AL.
Postoperative ultrasound (DUD) at follow-up (months)
2
Since the number of samples was small, we used a nonparametric paired test (Wilcoxon) to compare the difference of ureteral diameter before and after the treatment. All the patients affected by the above-stated criteria were treated with EHPBD of the VUJ, according to the technique described below. In the case of stenosis that was unresponsive to EHPBD, prolonged for up to 15 minutes, the balloon catheter was retracted and CBU was performed. The description of the patients and the outcome of the procedures are described in Table 1. Simple balloon catheter
An 8F to 9.8F cystoscope was used for the procedure. The dilation of the VUJ was performed with a balloon catheter (3F of diameter) filled with contrast medium for 5 to 15 minutes at the pressure of 12 to 14 atm. The balloon diameter at the maximum filling pressure was 4 mm. Cutting balloon
A small Peripheral Cutting Balloon (3F, balloon diameter 4 mm) was inserted across the VUJ through the cystoscope once the simple balloon catheter was retracted. Once in position, the cutting balloon was filled with the contrast medium to deploy the blades. A 4.7F Double-J stent was placed in all cases. The stent was then removed 6 to 8 weeks after the procedure (Fig. 1). A 4.7F Double-J stent was left in place for 6 to 8 weeks. Follow-up consisted of a renal ultrasound at 4 weeks after the Double-J removal and then every 3 months. MAG3 renography was performed 4 months after the procedure. Urinalysis was performed every month. The absence of urinary infection in all patients and the absence of reflux in the first five cases of our series meant that VCUG was not performed as routine. Results
No operative or postoperative complications were seen. The patients were discharged the day after the procedure. The follow-up was 2 to 44 months (mean 21 months). During the procedure, a clear stenotic ring was identified in 10 of the 12 patients. In two cases, no evidence of ureteral stenosis could be seen. In the 10 cases with a stenotic ring, the simple EHPBD was well performed in 7 cases. In the three cases with persistent ring after 15 minutes of EHPBD, a CBU was then performed resulting in the immediate and complete disappearance of the stenosis. At follow-up, 10 patients showed an improvement on ultrasound with no evidence of obstruction at the MAG3 renography. Two patients showed no improvement either on ultrasound or on MAG3. It is noteworthy that both these patients showed no evidence of a definite ureteral stenotic ring at the time of the procedure (Fig. 2). In these two patients, we performed open surgery (ureteroneocystostomy with ureteral tailoring) (Table 1). The median of pretreatment ureteral diameter was 18 mm (range 15–26 mm). The median of post-treatment was 10 mm (range 2–16 mm). There were statistically significant differences at the Wilcoxon test between baseline and postoperative ureteral diameter ( p = 0.002).
CUTTING BALLOON IN PRIMARY OBSTRUCTIVE MEGAURETER
3
FIG. 1. A small Peripheral Cutting Balloon.
Considering the whole series of patients treated endoscopically, the overall success rate of EHPBD + CBU was 83% (10/12). Discussion
The treatment of POM in infants is quite controversial. A conservative approach is indicated in most cases since POM tends to resolve spontaneously without any consequences for renal function.1–3 Nevertheless, there are severe cases of POM with increasing dilation, an obstructive pattern at renography, and/or decreased renal function; these can pose a risk of permanent renal damage. In such cases, there is a clear indication for surgery. Since the ureteroneocystostomy of a dilated ureter in a small bladder could be difficult and often associated with complications, some authors have suggested a temporary diversion (ureterostomy or ureteral stenting) to avoid the risk of renal damage and to reduce the size of the ureter until definitive surgical repair.6–11 The endoscopic dilatation of the VUJ, as the treatment of POM, has been shown to be feasible in children,12 even in those younger than 12 months.14,18 In our series, endoscopic treatment was given only in cases younger than 1 year, with a clear indication for surgery.
The most common finding at the endoscopic procedure was stenosis of a short tract of the distal ureter, with the appearance of a ring when the balloon catheter was inflated. The stenotic ring was extremely tough, and a balloon filling pressure exceeding 12 atm was needed to achieve its disappearance. In the three cases of our series, simple dilation with a balloon catheter was insufficient to make the ring disappear or even to reduce it, despite a dilation prolonged for up to 15 minutes at 15 atm. In cases that did not respond to EHPBD, the treatment with CBU was given, which achieved the immediate and complete disappearance of the ring. Conducting this study raised a number of questions that need to be addressed in the management of POM; for example, can CBU completely replace EHPBD? Should simple dilation precede or follow CBU? Is ureteral stenting really necessary after EHPBD/CBU? Regarding the first two, this study found that only the inflated balloon catheter allowed the identification of the true stenotic ring. In two cases, the authors could not identify any stricture. In such instances, dilation was not effective simply because there was nothing to dilate; CBU would have been ineffective for the same reason. Straightforward, EHPBD was well performed in most of the patients. Only its failure, seen in the three cases of our
FIG. 2. Flowchart of patients in the study. Overall success rate is 83%. EHPBD, endoscopic high-pressure balloon dilation.
4
CAPOZZA ET AL.
series, represented the indication to proceed to CBU. The authors are convinced, therefore, that this is the correct approach (dilation first and cutting next, if necessary), in disagreement with those19 who propose cutting before dilation. The last question regarding the real need for ureteral stenting after the procedure is again quite controversial. Routine stent placement has been questioned for a long time, especially in relation to balloon dilation and ureteroscopy for urolithiasis.20 The use of a stent is recommended only for the short period required to prevent the obstruction and renal failure due to edema, epithelial hyperplasia, or inflammatory cell reaction.21 Moreover, some authors have recently suggested that the ureteral stent is not necessary in uncomplicated procedures.22,23 Nevertheless, cases involving patients younger than 18 years and cases involving mucosal damage are considered as absolute indications for stenting. Therefore, in our series of infants younger than 1 year who underwent EHPBD, ureteral stenting seemed appropriate; and even more so in the infants who underwent CBU since the mucosa was damaged. A further question regarding the period of time that the stent should be maintained. In experimental studies, ureteral edema and consequent obstruction have been observed for more than 72 to 96 hours after ureteral dilation.24 In a study comparing two groups of patients with and without stent, the authors did not find any difference in terms of postoperative complications.20 Considering the age of the patients, we confirm the absolute indication for ureteral stenting, although the recommended time of 6 to 8 weeks could probably be reduced to 2 weeks.
6. 7. 8. 9.
10.
11.
12.
13. 14.
Conclusions
POM in infants can be treated endoscopically as a mininvasive alternative to open surgery. EHPBD has confirmed itself to be safe and effective in most cases. The endoscopic procedure used also allowed the identification of a stenotic ring of the distal ureter as the most common cause of obstruction. In the case of a persistent ring that is unresponsive to EHPBD, CBU seems to provide a valid definitive treatment of POM.
15.
Disclosure Statement
17.
16.
No competing financial interests exist. References
1. Keating MA, Escala J, Snyder HM, III, et al. Changing concepts in management of primary obstructive megaureter. J Urol 1989;142:636–640. 2. Baskin LS, Zderic SA, Snyder HM, Duckett JW. Primary dilated megaureter: Long-term followup. J Urol 1994;152: 618–621. 3. McLellan DL, Retik AB, Bauer SB, et al. Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter. J Urol 2002;168:2177–2180. 4. Peters CA, Mandell J, Lebowitz RL, et al. Congenital obstructed megaureters in early infancy: Diagnosis and treatment. J Urol 1989;142:641–645. 5. Stehr M, Metzger R, Schuster T, et al. Management of the primary obstructed megaureter (POM) and indication
18.
19. 20.
21.
for operative treatment. Eur J Pediatr Surg 2002;12:32– 37. Hendren WH. Operative repair of megaureter in children. J Urol 1969;101:491–507. Hendren WH. Technical aspects of megaureter repair. Birth Defects Orig Artic Ser 1977;13:21–33. Ransley PG, Dhillon HK, Gordon I, et al. The postnatal management of hydronephrosis diagnosed by prenatal ultrasound. J Urol 1990;144:584–587. Castagnetti M, Cimador M, Sergio M, De Grazia E. Double-J stent insertion across vesicoureteral junction—is it a valuable initial approach in neonates and infants with severe primary nonrefluxing megaureter? Urology 2006;68: 870–876. Carroll D, Chandran H, Joshi A, et al. Endoscopic placement of Double-J ureteric stents in children as a treatment for primary obstructive megaureter. Urol Ann 2010;2:114– 118. Farrugia MK, Steinbrecher HA, Malone PS. The utilization of stents in the management of primary obstructive megaureters requiring intervention before 1 year of age. J Pediatr Urol 2011;7:198–202. Angulo JM, Arteaga R, Rodrı´guez Alarco´n J, Calvo MJ. Role of retrograde endoscopic dilatation with balloon and derivation using double pig-tail catheter as an initial treatment for vesico-ureteral junction stenosis in children (Article in Spanish). Cir Pediatr 1998;11: 15–18. Angerri O, Caffaratti J, Garat JM, Villavicencio H. Primary obstructive megaureter: Initial experience with endoscopic dilatation. J Endourol 2007;21:999–1004. Torino G, Collura G, Mele E, et al. Severe primary obstructive megaureter in the first year of life: Preliminary experience with endoscopic balloon dilation. J Endourol 2012;26:325–329. Conway JJ, Maizels M. The ‘‘well tempered’’ diuretic renogram: A standard method to examine the asymptomatic neonate with hydronephrosis or hydroureteronephrosis. A report from combined meetings of The Society for Fetal Urology and members of The Pediatric Nuclear Medicine Council—The Society of Nuclear Medicine. J Nucl Med 1992;33:2047–2051. Mandell GA, Cooper JA, Leonard JC, et al. Procedure guideline for diuretic renography in children. J Nucl Med 1997;38:1647–1650. Shulkin BL, Mandell GA, Cooper JA, et al. Procedure guideline for diuretic renography in children 3.0. J Nucl Med Technol 2008;36:162–168. Garcia-Aparicio L, Blazquez-Go`mez E, Martin O, et al. Use of high-pressure balloon dilatation of the ureterovesical junction instead of ureteral reimplantation to treat primary obstructive megaureter: I sit justified? J Pediatr Urol 2013;9(6 Pt B):1229–1233. Smeulders N, Yankovic F, Chippington S, Cherian A. Primary obstructive megaureter: Cutting balloon endo-ureterotomy. J Pediatr Urol 2013;9:692.e1–e2. Basxeskiog˘lu B, Sofikerim M, Demirtasx A, Yenilmez A, Kaya C, Can C. Is ureteral stenting really necessary after ureteroscopic lithotripsy with balloon dilatation of ureteral orifice? A multi-institutional randomized controlled study. World J Urol 2011;29:731–736. Lumiaho J, Heino A, Pietila¨inen T, Ala-Opas M, Talja M, Va¨limaa T, To¨rma¨la¨ P. The morphological, in situ effects of a self-reinforced bioabsorbable polylactide (SR-PLA 96)
CUTTING BALLOON IN PRIMARY OBSTRUCTIVE MEGAURETER
ureteric stent; an experimental study. J Urol 2000;164: 1360–1363. 22. Byrne RR, Auge BK, Kourambas J, Munver R, Delvecchio F, Preminger GM. Routine ureteral stenting is not necessary after ureteroscopy and ureteropyeloscopy: A randomized trial. J Endourol 2002;16:9–13. 23. Borboroglu PG, Amling CL, Schenkman NS, Monga M, Ward JF, Piper NY, Bishoff JT, Kane CJ. Ureteral stenting after ureteroscopy for distal ureteral calculi: A multiinstitutional prospective randomized controlled study assessing pain, outcomes and complications. J Urol 2001;166: 1651–1657. 24. Boddy SA, Nimmon CC, Jones S, Ramsay JW, Britton KE, Levison DA, Whitifield HN. Acute ureteric dilatation for ureteroscopy. An experimental study. Br J Urol 1988;61: 27–31.
5
Address correspondence to: Nicola Capozza, MD Surgical Unit of the Pediatric Urology ‘‘Bambino Gesu`’’ Children’s Hospital and Research Institute Rome 00165 Italy E-mail: [email protected] Abbreviations Used CBU ¼ cutting balloon ureterotomy EHPBD ¼ endoscopic high-pressure balloon dilation POM ¼ primary obstructive megaureter UTI ¼ urinary tract infection VCUG ¼ voiding cystourethrogram VUJ ¼ vesicoureteral junction
JOURNAL OF ENDOUROLOGY Volume 00, Number 00, XXXXXX 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2013.0665
Primary Obstructive Megaureter in Infants: Our Experience with Endoscopic Balloon Dilation and Cutting Balloon Ureterotomy Nicola Capozza, MD, Giovanni Torino, MD, PhD, Simona Nappo, MD, Giuseppe Collura, MD, PhD, and Ermelinda Mele, MD
Abstract
The management of primary obstructive megaureter (POM) is usually conservative, at least in the first year of life. Nevertheless, in high-grade POMs with increasing dilation, obstructive patterns found at renography, or cases involving decreased renal function, there is a clear indication for surgery. From January 2009 to March 2013, 12 patients, aged 6 to 12 months (mean 8 months), were treated endoscopically for POM. At the procedure, a clear stenotic ring was identified in 10 of the 12 patients, and a simple endoscopic high-pressure balloon dilation (EHPBD) was well performed in 7 patients. In the three cases with persistent ring, a cutting balloon ureterotomy (CBU) was then performed, resulting in the immediate and complete disappearance of the stenosis. In two cases, no ring could be seen at the procedure, and they showed no improvement at the follow-up. The mean follow-up was 21 months. Considering the whole series of patients treated endoscopically, the overall success rate of EHPBD + CBU was 83%. Patients with POM can be treated endoscopically. In the case of a persistent ring that is unresponsive to EHPBD, CBU seems to provide a valid definitive treatment of POM.
Introduction
Patients and Methods
T
From January 2009 to March 2013, 12 patients, aged 6 to 12 months (mean age 8 months), were treated endoscopically for POM. This series represents about 10% of all nonrefluxing megaureters followed in the same period at our institution. As described in a previous article,14 during this preliminary experience employing endoscopic treatment of POM, all the patients were initially evaluated using renal ultrasound in the first month of life as a follow-up to prenatal hydronephrosis. Renal and urinary tract ultrasound was then repeated every 2 months. Voiding cystourethrogram (VCUG) was performed in all cases. MAG3 renal imaging was performed between 1 and 2 months after birth, with the assessment of differential renal function and isotope washout. In the case of poor urinary drainage at the basal reno/ ureterogram, a diuretic test was performed. Washout halftime (T½) of > 20 minutes was taken as representing an obstruction.15–17 The inclusion criteria for the study were initial dilation of the distal ureter > 15 mm, increasing dilation at follow-up, urinary tract infection (UTI), and obstruction at MAG3 renography.
he management of primary obstructive megaureter (POM) is usually conservative, at least in the first year of life.1–3 Nevertheless, there are certain circumstances, such as high-grade POMs with increasing dilation, obstructive patterns found at renography, or cases involving decreased renal function that do not permit delay, given the risk of permanent renal damage.4,5 Until a few years ago, these cases were managed using temporary urinary diversion (ureterostomy, ureteral stenting),6–11 awaiting definitive surgical repair; this was conventionally indicated after 1 year of age. Recently, endoscopic high-pressure balloon dilation (EHPBD) of the vesicoureteral junction (VUJ) has been proposed as an alternative to surgery in the first year of life.12–14 The results have generally been extremely satisfactory. However, in some cases, the procedure remains only partially well performed despite prolonged dilation. In such cases of stenosis that do not respond to high-pressure dilation, the authors of this work completed the procedure by employing cutting balloon ureterotomy (CBU). We analyzed the outcome of a series of infants with obstructive megaureter, treated endoscopically by balloon dilation and CBU.
Surgical Unit of the Pediatric Urology, ‘‘Bambino Gesu`’’ Children’s Hospital and Research Institute, Rome, Italy.
1
CBU = cutting balloon ureterotomy; DUD = distal ureteral diameter; EHPBD = endoscopic high-pressure balloon dilation; F = female; ID = increasing dilatation; L = left; M = male; Obstruction (O) = T/2 > 20 minutes after diuretic during renography; No obstruction = good urinary drainage out of the ROIs at 30 minutes after injection of the MAG-3 without diuretic test; OPEN = reimplantation with open technique; R = right; UTI = urinary tract infection.
/ CBU / CBU / OPEN
/ OPEN / CBU
EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD EHPBD No No No No No Yes No No No No Yes No 6 12 6 6 10 9 11 8 9 12 12 6 ID + O ID + O ID + O ID + O UTI + O ID + O ID + O UTI + O UTI + O UTI + O ID + O ID + O M M M M F F M F M M F M
L R L R R L L R L L L L
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
R: R: R: R: R: R: R: R: R: R: R: R:
55%; 44%; 53%; 47%; 51%; 50%; 60%; 49%; 62%; 49%; 53%; 67%;
45%/R: 56%/R: 47%/R: 53%/R: 49%/R: 50%/R: 40%/R: 51%/R: 38%/R: 51%/R: 47%/R: 33%/R: L: L: L: L: L: L: L: L: L: L: L: L: 1 2 3 4 5 6 7 8 9 10 11 12
54%; 45%; 55%; 47%; 55%; 50%; 58%; 51%; 45%; 50%; 54%; 65%;
L: L: L: L: L: L: L: L: L: L: L: L:
46% 55% 45% 53% 45% 50% 42% 49% 55% 50% 46% 35%
22 mm 19 mm 18 mm 19 mm 16 mm 17 mm 22 mm 16 mm 15 mm 16 mm 18 mm 26 mm
Procedures Postoperative Last obstruction preoperative Indication Age at surgery pattern at MAG-3 ultrasound for surgery (months) diuretic renography (DUD) Preoperative/ postoperative split renal function Preoperative obstruction pattern at MAG-3 diuretic Affected renography Patients Sex side
Table 1. Outcomes and Characteristics of the Patients
11 mm at 44 9 mm at 42 3 mm at 38 2 mm at 35 13 mm at 30 16 mm at 18 8 mm at 14 11 mm at 11 9 mm at 9 9 mm at 7 16 mm at 6 15 mm at 2
CAPOZZA ET AL.
Postoperative ultrasound (DUD) at follow-up (months)
2
Since the number of samples was small, we used a nonparametric paired test (Wilcoxon) to compare the difference of ureteral diameter before and after the treatment. All the patients affected by the above-stated criteria were treated with EHPBD of the VUJ, according to the technique described below. In the case of stenosis that was unresponsive to EHPBD, prolonged for up to 15 minutes, the balloon catheter was retracted and CBU was performed. The description of the patients and the outcome of the procedures are described in Table 1. Simple balloon catheter
An 8F to 9.8F cystoscope was used for the procedure. The dilation of the VUJ was performed with a balloon catheter (3F of diameter) filled with contrast medium for 5 to 15 minutes at the pressure of 12 to 14 atm. The balloon diameter at the maximum filling pressure was 4 mm. Cutting balloon
A small Peripheral Cutting Balloon (3F, balloon diameter 4 mm) was inserted across the VUJ through the cystoscope once the simple balloon catheter was retracted. Once in position, the cutting balloon was filled with the contrast medium to deploy the blades. A 4.7F Double-J stent was placed in all cases. The stent was then removed 6 to 8 weeks after the procedure (Fig. 1). A 4.7F Double-J stent was left in place for 6 to 8 weeks. Follow-up consisted of a renal ultrasound at 4 weeks after the Double-J removal and then every 3 months. MAG3 renography was performed 4 months after the procedure. Urinalysis was performed every month. The absence of urinary infection in all patients and the absence of reflux in the first five cases of our series meant that VCUG was not performed as routine. Results
No operative or postoperative complications were seen. The patients were discharged the day after the procedure. The follow-up was 2 to 44 months (mean 21 months). During the procedure, a clear stenotic ring was identified in 10 of the 12 patients. In two cases, no evidence of ureteral stenosis could be seen. In the 10 cases with a stenotic ring, the simple EHPBD was well performed in 7 cases. In the three cases with persistent ring after 15 minutes of EHPBD, a CBU was then performed resulting in the immediate and complete disappearance of the stenosis. At follow-up, 10 patients showed an improvement on ultrasound with no evidence of obstruction at the MAG3 renography. Two patients showed no improvement either on ultrasound or on MAG3. It is noteworthy that both these patients showed no evidence of a definite ureteral stenotic ring at the time of the procedure (Fig. 2). In these two patients, we performed open surgery (ureteroneocystostomy with ureteral tailoring) (Table 1). The median of pretreatment ureteral diameter was 18 mm (range 15–26 mm). The median of post-treatment was 10 mm (range 2–16 mm). There were statistically significant differences at the Wilcoxon test between baseline and postoperative ureteral diameter ( p = 0.002).
CUTTING BALLOON IN PRIMARY OBSTRUCTIVE MEGAURETER
3
FIG. 1. A small Peripheral Cutting Balloon.
Considering the whole series of patients treated endoscopically, the overall success rate of EHPBD + CBU was 83% (10/12). Discussion
The treatment of POM in infants is quite controversial. A conservative approach is indicated in most cases since POM tends to resolve spontaneously without any consequences for renal function.1–3 Nevertheless, there are severe cases of POM with increasing dilation, an obstructive pattern at renography, and/or decreased renal function; these can pose a risk of permanent renal damage. In such cases, there is a clear indication for surgery. Since the ureteroneocystostomy of a dilated ureter in a small bladder could be difficult and often associated with complications, some authors have suggested a temporary diversion (ureterostomy or ureteral stenting) to avoid the risk of renal damage and to reduce the size of the ureter until definitive surgical repair.6–11 The endoscopic dilatation of the VUJ, as the treatment of POM, has been shown to be feasible in children,12 even in those younger than 12 months.14,18 In our series, endoscopic treatment was given only in cases younger than 1 year, with a clear indication for surgery.
The most common finding at the endoscopic procedure was stenosis of a short tract of the distal ureter, with the appearance of a ring when the balloon catheter was inflated. The stenotic ring was extremely tough, and a balloon filling pressure exceeding 12 atm was needed to achieve its disappearance. In the three cases of our series, simple dilation with a balloon catheter was insufficient to make the ring disappear or even to reduce it, despite a dilation prolonged for up to 15 minutes at 15 atm. In cases that did not respond to EHPBD, the treatment with CBU was given, which achieved the immediate and complete disappearance of the ring. Conducting this study raised a number of questions that need to be addressed in the management of POM; for example, can CBU completely replace EHPBD? Should simple dilation precede or follow CBU? Is ureteral stenting really necessary after EHPBD/CBU? Regarding the first two, this study found that only the inflated balloon catheter allowed the identification of the true stenotic ring. In two cases, the authors could not identify any stricture. In such instances, dilation was not effective simply because there was nothing to dilate; CBU would have been ineffective for the same reason. Straightforward, EHPBD was well performed in most of the patients. Only its failure, seen in the three cases of our
FIG. 2. Flowchart of patients in the study. Overall success rate is 83%. EHPBD, endoscopic high-pressure balloon dilation.
4
CAPOZZA ET AL.
series, represented the indication to proceed to CBU. The authors are convinced, therefore, that this is the correct approach (dilation first and cutting next, if necessary), in disagreement with those19 who propose cutting before dilation. The last question regarding the real need for ureteral stenting after the procedure is again quite controversial. Routine stent placement has been questioned for a long time, especially in relation to balloon dilation and ureteroscopy for urolithiasis.20 The use of a stent is recommended only for the short period required to prevent the obstruction and renal failure due to edema, epithelial hyperplasia, or inflammatory cell reaction.21 Moreover, some authors have recently suggested that the ureteral stent is not necessary in uncomplicated procedures.22,23 Nevertheless, cases involving patients younger than 18 years and cases involving mucosal damage are considered as absolute indications for stenting. Therefore, in our series of infants younger than 1 year who underwent EHPBD, ureteral stenting seemed appropriate; and even more so in the infants who underwent CBU since the mucosa was damaged. A further question regarding the period of time that the stent should be maintained. In experimental studies, ureteral edema and consequent obstruction have been observed for more than 72 to 96 hours after ureteral dilation.24 In a study comparing two groups of patients with and without stent, the authors did not find any difference in terms of postoperative complications.20 Considering the age of the patients, we confirm the absolute indication for ureteral stenting, although the recommended time of 6 to 8 weeks could probably be reduced to 2 weeks.
6. 7. 8. 9.
10.
11.
12.
13. 14.
Conclusions
POM in infants can be treated endoscopically as a mininvasive alternative to open surgery. EHPBD has confirmed itself to be safe and effective in most cases. The endoscopic procedure used also allowed the identification of a stenotic ring of the distal ureter as the most common cause of obstruction. In the case of a persistent ring that is unresponsive to EHPBD, CBU seems to provide a valid definitive treatment of POM.
15.
Disclosure Statement
17.
16.
No competing financial interests exist. References
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Address correspondence to: Nicola Capozza, MD Surgical Unit of the Pediatric Urology ‘‘Bambino Gesu`’’ Children’s Hospital and Research Institute Rome 00165 Italy E-mail: [email protected] Abbreviations Used CBU ¼ cutting balloon ureterotomy EHPBD ¼ endoscopic high-pressure balloon dilation POM ¼ primary obstructive megaureter UTI ¼ urinary tract infection VCUG ¼ voiding cystourethrogram VUJ ¼ vesicoureteral junction
