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Pediatrics: UPJO & Megaureter: Difference between revisions

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* '''See [[Ureteropelvic Junction Obstruction]] Chapter Notes'''
* '''See [[Ureteropelvic Junction Obstruction]] Chapter Notes'''
'''Management'''
 
=== Differential Diagnosis of Hydronephrosis in Child ===
 
# '''Ureteropelvic junction obstruction'''
# '''Multicyclic dysplastic kidney'''
# '''Ureteral stone'''
# '''Extrarenal pelvis'''
# '''Malignant ureteral obstruction'''
# '''Megaureter'''
# '''Peripelvic cyst'''
# '''Retrocaval ureter'''
# '''Vesicoureteral reflux (VUR)'''
# '''Fibroepithelial polyp'''
# '''Calyceal diverticulum'''
 
=== Management ===
 
==== Options (2): ====
# '''Observation'''
# '''Surgical intervention'''
##'''Endoscopic'''
##'''Pyeloplasty'''
 
===== Observation =====
* Only ≈1/3 of affected children will need surgical intervention
* Only ≈1/3 of affected children will need surgical intervention
* '''Indications for surgery (4):'''
 
*# '''Symptoms'''
===== '''Intervention''' =====
*# '''Infections''' while on prophylactic antibiotics
====== '''Indications (4):''' ======
*# '''Increasing hydronephrosis'''
# '''Symptoms'''
*# Low or decreasing differential '''renal function'''
# '''Infections''' while on prophylactic antibiotics
* '''Options: pyeloplasty vs. endoscopic'''
# '''Increasing hydronephrosis'''
** '''Pyeloplasty'''
# Low or decreasing differential '''renal function'''
*** '''Dismembered Pyeloplasty'''
 
**** '''Improved outcomes over non-dismemembered approach in the repair of a UPJO'''
====== Pyeloplasty ======
***** '''Anderson-Hynes dismembered pyeloplasty is the preferred technique  '''
* '''Dismembered Pyeloplasty'''
***** '''Advantages of dismembering the UPJ (3):'''
** '''Improved outcomes over non-dismemembered approach in the repair of a UPJO'''
*****# '''A vessel crossing the lower pole can be preserved'''
*** '''Anderson-Hynes dismembered pyeloplasty is the preferred technique  '''
*****# '''The adynamic part of the ureter excised'''
*** '''Advantages of dismembering the UPJ (3):'''
*****# '''Redundant pelvic tissue reduced'''
***# '''A vessel crossing the lower pole can be preserved'''
****** Main steps of the Anderson-Hynes dismembered pyeloplasty:
***# '''The adynamic part of the ureter excised'''
******* After opening the Gerota fascia, the anterior or posterior aspect of the UPJ is dissected (depending on the access used). The lower pole of the kidney is freed to avoid overlooking an accessory vessel. Electrocautery should be used with caution to minimize damage to the blood supply of both the pelvis and the ureter, with preference given to bipolar diathermy.
***# '''Redundant pelvic tissue reduced'''
******* A stay suture is placed in the pelvis proximal to the anticipated line of dismemberment; another stay suture can be placed in the ureter at the level of the stenosis.
**** Main steps of the Anderson-Hynes dismembered pyeloplasty:
******* The UPJ is dismembered, and the pelvis reduced if indicated. A tensely dilated pelvis should be decompressed with a 21-gauge needle before dismembering, to avoid excessive pelvic reduction.
***** After opening the Gerota fascia, the anterior or posterior aspect of the UPJ is dissected (depending on the access used). The lower pole of the kidney is freed to avoid overlooking an accessory vessel. Electrocautery should be used with caution to minimize damage to the blood supply of both the pelvis and the ureter, with preference given to bipolar diathermy.
******* The ureter is then spatulated along its lateral border, well beyond the dysplastic stenotic segment and carried through adequately into healthy ureteral tissue. At this stage, the stenotic part of the ureter should not be removed, because it can serve as a handle that minimizes ureteral tissue manipulation while performing the anastomosis, reducing the risk for mucosal edema.
***** A stay suture is placed in the pelvis proximal to the anticipated line of dismemberment; another stay suture can be placed in the ureter at the level of the stenosis.
******* The anastomosis can be completed with interrupted or continuous suturing. Suture size depends on the prevailing anatomy, but most often a 6-0 or 5-0 resorbable monofilament suture on a round needle is used. Care should be taken at the tip of the V of the anastomosis, which has to be assembled precisely and in a tension-free manner. Placing inadvertent excessive tension on the stay sutures while aligning the anastomosis should be avoided because it can lead to kinking of the ureter once tension is relieved.
***** The UPJ is dismembered, and the pelvis reduced if indicated. A tensely dilated pelvis should be decompressed with a 21-gauge needle before dismembering, to avoid excessive pelvic reduction.
******* Just before completing the anastomosis, the stenotic part of the ureter is removed and the pelvis is irrigated with saline to avoid blood clots obstructing the ureter.
***** The ureter is then spatulated along its lateral border, well beyond the dysplastic stenotic segment and carried through adequately into healthy ureteral tissue. At this stage, the stenotic part of the ureter should not be removed, because it can serve as a handle that minimizes ureteral tissue manipulation while performing the anastomosis, reducing the risk for mucosal edema.
******* Stenting the anastomosis is a matter of choice
***** The anastomosis can be completed with interrupted or continuous suturing. Suture size depends on the prevailing anatomy, but most often a 6-0 or 5-0 resorbable monofilament suture on a round needle is used. Care should be taken at the tip of the V of the anastomosis, which has to be assembled precisely and in a tension-free manner. Placing inadvertent excessive tension on the stay sutures while aligning the anastomosis should be avoided because it can lead to kinking of the ureter once tension is relieved.
******* The kidney is brought back to its native position, and the anastomosis can be covered with perinephric fat if available.
***** Just before completing the anastomosis, the stenotic part of the ureter is removed and the pelvis is irrigated with saline to avoid blood clots obstructing the ureter.
******* Usually the use of external drainage in the form of a Penrose is not indicated
***** Stenting the anastomosis is a matter of choice
*** '''Non-dismembered Pyeloplasty'''
***** The kidney is brought back to its native position, and the anastomosis can be covered with perinephric fat if available.
**** '''Techniques: Heineke-Mikulicz, Foley Y-V plasty'''
***** Usually the use of external drainage in the form of a Penrose is not indicated
*** '''Laparoscopic vs. open pyeloplasties'''
* '''Non-dismembered Pyeloplasty'''
**** Laparoscopic pyeloplasties provide excellent visualization of the anatomy, enhance cosmesis, and duplicate the results of open pyeloplasties with short-term follow-up.
** '''Techniques: Heineke-Mikulicz, Foley Y-V plasty'''
***** During laparoscopy monopolar cautery increases the risk of unrecognized lesions to intra-abdominal organs, particularly the bowel.
* '''Laparoscopic vs. open pyeloplasties'''
***** The technical challenges of this approach have been facilitated by the use of a robotic-assisted procedure that improves the anastomotic repair
** Laparoscopic pyeloplasties provide excellent visualization of the anatomy, enhance cosmesis, and duplicate the results of open pyeloplasties with short-term follow-up.
***** Trocars should not be removed before the intra-abdominal pressure is close to normal. Lowering the pressure before removing the trocars will reveal that the hemostasis is under control and prevents intra-abdominal (bowel, omentum) content from entering the port holes.
*** During laparoscopy monopolar cautery increases the risk of unrecognized lesions to intra-abdominal organs, particularly the bowel.
***** The peritoneal lining mirrors the light from the telescope, giving the transperitoneal approach better visibility than in the retroperitoneal route.
*** The technical challenges of this approach have been facilitated by the use of a robotic-assisted procedure that improves the anastomotic repair
***** Horseshoe kidneys are a relative contraindication to the retroperitoneal approach as access to the UPJ from the posterior aspect is extremely difficult
*** Trocars should not be removed before the intra-abdominal pressure is close to normal. Lowering the pressure before removing the trocars will reveal that the hemostasis is under control and prevents intra-abdominal (bowel, omentum) content from entering the port holes.
***** Hypothermia during laparoscopy in all infants is caused by insufflation of a large amount of CO2 due to port leakage.
*** The peritoneal lining mirrors the light from the telescope, giving the transperitoneal approach better visibility than in the retroperitoneal route.
***** Bladeless optical trocars or open access for the camera port might be helpful for pediatric minimally invasive surgery in obese patients
*** Horseshoe kidneys are a relative contraindication to the retroperitoneal approach as access to the UPJ from the posterior aspect is extremely difficult
**** '''Newborns may be more suitable for open pyeloplasty since access to the ureteropelvic junction (UPJ) requires only a very small incision.'''
*** Hypothermia during laparoscopy in all infants is caused by insufflation of a large amount of CO2 due to port leakage.
*** '''Complications (3):'''
*** Bladeless optical trocars or open access for the camera port might be helpful for pediatric minimally invasive surgery in obese patients
***# '''Prolonged urinary drainage postoperatively'''
** '''Newborns may be more suitable for open pyeloplasty since access to the ureteropelvic junction (UPJ) requires only a very small incision.'''
***# '''Lack of improvement in renal function or improvement in washout'''
* '''Complications (3):'''
***# '''Occasionally, worsening hydronephrosis and diminished renal function post-operatively'''
*# '''Prolonged urinary drainage postoperatively'''
***#* '''Such a situation may lend itself to a repair using endoscopic procedures or a repeat dismembered pyeloplasty'''
*# '''Lack of improvement in renal function or improvement in washout'''
** '''Endoscopic'''
*# '''Occasionally, worsening hydronephrosis and diminished renal function post-operatively'''
*** '''Preoperative screening for accessory vessels is required by CT, MRI, or transluminal US, so as to avoid vascular injury'''
*#* '''Such a situation may lend itself to a repair using endoscopic procedures or a repeat dismembered pyeloplasty'''
*** '''Endopyelotomy may have a place in the management of failed primary open or laparoscopic procedures followed by the placement of a double-pigtail catheter for 6 weeks. A repeat pyeloplasty, either open or laparoscopically, is the best choice in most cases.'''
 
====== Endoscopic ======
* '''Preoperative screening for accessory vessels is required by CT, MRI, or transluminal US, so as to avoid vascular injury'''
* '''Endopyelotomy may have a place in the management of failed primary open or laparoscopic procedures followed by the placement of a double-pigtail catheter for 6 weeks. A repeat pyeloplasty, either open or laparoscopically, is the best choice in most cases.'''


== Megaureter ==
== Megaureter ==


* '''Definition of megaureter: dilatation of the ureter irrespective of cause'''
* '''Definition of megaureter: dilatation of the ureter irrespective of cause'''
* '''Classified as primary vs. secondary'''
 
=== Classification ===
*'''Classified as primary vs. secondary'''
** '''Primary obstructed megaureters (POM)'''
** '''Primary obstructed megaureters (POM)'''
*** '''A condition intrinsic to the ureter itself;''' '''obstruction results from the presence of an abnormal adynamic segment at the terminal end of the ureter near or at the ureterovesical junction (UVJ)'''
*** '''A condition intrinsic to the ureter itself;''' '''obstruction results from the presence of an abnormal adynamic segment at the terminal end of the ureter near or at the ureterovesical junction (UVJ)'''
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*# '''Non-obstructed non-refluxing'''
*# '''Non-obstructed non-refluxing'''
*# '''Refluxing with obstruction'''
*# '''Refluxing with obstruction'''
* '''Management'''
 
** The goal is to prevent renal functional deterioration with either conservative or surgical treatment
=== Management ===
** '''Conservative'''
* The goal is to prevent renal functional deterioration with either conservative or surgical treatment
*** '''> 90% of antenatally detected non-refluxing, non-obstructing megaureters will improve with conservative management within the first few years of life'''
* '''Conservative'''
*** '''Patients with ureteral diameters > 10 mm were more prone to complications'''
** '''> 90% of antenatally detected non-refluxing, non-obstructing megaureters will improve with conservative management within the first few years of life'''
** '''Surgery'''
** '''Patients with ureteral diameters > 10 mm were more prone to complications'''
*** '''Indications for surgery of POM (5):'''
* '''Surgery'''
***# '''Symptoms'''
** '''Indications for surgery of POM (5):'''
***# '''Infections''' (recurring UTIs)
**# '''Symptoms'''
***# '''Increasing hydronephrosis/hydroureter'''
**# '''Infections''' (recurring UTIs)
***# '''< 40% differential renal function'''
**# '''Increasing hydronephrosis/hydroureter'''
***# '''≥ 5% decrease in differential renal function of on sequential “comparable” nuclear functional studies'''
**# '''< 40% differential renal function'''
***#* '''The T 1/2, or Lasix washout time, especially in neonatal megaureters is not a reliable indicator of obstruction'''
**# '''≥ 5% decrease in differential renal function of on sequential “comparable” nuclear functional studies'''
***#** Washout curves in neonates and infants can be affected by many factors other than restriction of flow.
**#* '''The T 1/2, or Lasix washout time, especially in neonatal megaureters is not a reliable indicator of obstruction'''
***#** A normal creatinine and symmetric renal function support initial observation in a child
**#** Washout curves in neonates and infants can be affected by many factors other than restriction of flow.
*** '''Options (3):'''
**#** A normal creatinine and symmetric renal function support initial observation in a child
***# '''Decompression'''
** '''Options (3):'''
***#* '''Indications for prompt decompression:'''
**# '''Decompression'''
***#*# '''Neonate with a megaureter and sepsis'''
**#* '''Indications for prompt decompression:'''
***#*# Ipsilateral reduced function (< 35% in a neonate)
**#*# '''Neonate with a megaureter and sepsis'''
***#*# Marked or increasing hydroureteronephrosis
**#*# Ipsilateral reduced function (< 35% in a neonate)
***#* '''Options (2):'''
**#*# Marked or increasing hydroureteronephrosis
***#*# '''Distal cutaneous ureterostomy (preferred)'''
**#* '''Options (2):'''
***#*# Nephrostomy tube
**#*# '''Distal cutaneous ureterostomy (preferred)'''
***#*#* Nephrostomy tubes are difficult to keep in place
**#*# Nephrostomy tube
***# '''Endoscopic'''
**#*#* Nephrostomy tubes are difficult to keep in place
***#* '''Endoscopic dilatation and stenting of the UVJ in POM is an alternative''' that is less invasive than formal open or laparoscopic surgical intervention, with short- to medium-term success rates ≈70%
**# '''Endoscopic'''
***# '''Surgical repair'''
**#* '''Endoscopic dilatation and stenting of the UVJ in POM is an alternative''' that is less invasive than formal open or laparoscopic surgical intervention, with short- to medium-term success rates ≈70%
***#* '''Excision and tapered re-implant'''
**# '''Surgical repair'''
***#** The stenotic distal part of the ureter is excised
**#* '''Excision and tapered re-implant'''
***#** The megaureter is straightened and then tapered to facilitate reimplantation in a nonrefluxing fashion with '''adequate ratio of length to diameter of 5:1 to improve coaptation of the ureteral lumen''', whereby effective peristalsis and urine transportation are achieved
**#** The stenotic distal part of the ureter is excised
***#*** '''Ureteral tailoring is usually necessary''' to achieve the proper length-to-diameter ratio required of successful reimplants. Especially in small children, the reimplant can be otherwise impossible.
**#** The megaureter is straightened and then tapered to facilitate reimplantation in a nonrefluxing fashion with '''adequate ratio of length to diameter of 5:1 to improve coaptation of the ureteral lumen''', whereby effective peristalsis and urine transportation are achieved
***#*** '''Folding techniques for ureteral tailoring are not applicable in ureters >1.75 cm in diameter.'''
**#*** '''Ureteral tailoring is usually necessary''' to achieve the proper length-to-diameter ratio required of successful reimplants. Especially in small children, the reimplant can be otherwise impossible.
***#*** The most serious complication to ureteral tailoring is compromise of the distal vasculature of the ureter with subsequent fibrosis.
**#*** '''Folding techniques for ureteral tailoring are not applicable in ureters >1.75 cm in diameter.'''
***#**** Fibrosis can lead to recurrent obstruction and require a redo. However, when performed with care, the risk of vascular compromise should be minimal
**#*** The most serious complication to ureteral tailoring is compromise of the distal vasculature of the ureter with subsequent fibrosis.
***#** Most surgeons advocate temporary postoperative stenting
**#**** Fibrosis can lead to recurrent obstruction and require a redo. However, when performed with care, the risk of vascular compromise should be minimal
***#* '''Complications: obstruction, vesicoureteric reflux, and persistent dilatation'''
**#** Most surgeons advocate temporary postoperative stenting
***#* A concomitant reimplantation and dismembered pyeloplasty should be discouraged, as the ureteral blood supply may be compromised.
**#* '''Complications: obstruction, vesicoureteric reflux, and persistent dilatation'''
**#* A concomitant reimplantation and dismembered pyeloplasty should be discouraged, as the ureteral blood supply may be compromised.


== Congenital ureteral strictures ==
== Congenital ureteral strictures ==
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