Editing Pediatrics: UPJO & Megaureter (section)

== Ureteropelvic Junction Obstruction (UJPO) ==

* '''See [[Ureteropelvic Junction Obstruction]] Chapter Notes'''

=== 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

===== '''Intervention''' =====
====== '''Indications (4):''' ======
# '''Symptoms'''
# '''Infections''' while on prophylactic antibiotics
# '''Increasing hydronephrosis'''
# Low or decreasing differential '''renal function'''

====== Pyeloplasty ======
* '''Dismembered Pyeloplasty'''
** '''Improved outcomes over non-dismemembered approach in the repair of a UPJO'''
*** '''Anderson-Hynes dismembered pyeloplasty is the preferred technique  '''
*** '''Advantages of dismembering the UPJ (3):'''
***# '''A vessel crossing the lower pole can be preserved'''
***# '''The adynamic part of the ureter excised'''
***# '''Redundant pelvic tissue reduced'''
**** Main steps of the Anderson-Hynes dismembered pyeloplasty:
***** 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.
***** 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 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.
***** 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.
***** 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.
***** 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.
***** Stenting the anastomosis is a matter of choice
***** The kidney is brought back to its native position, and the anastomosis can be covered with perinephric fat if available.
***** Usually the use of external drainage in the form of a Penrose is not indicated
* '''Non-dismembered Pyeloplasty'''
** '''Techniques: Heineke-Mikulicz, Foley Y-V plasty'''
* '''Laparoscopic vs. open pyeloplasties'''
** Laparoscopic pyeloplasties provide excellent visualization of the anatomy, enhance cosmesis, and duplicate the results of open pyeloplasties with short-term follow-up.
*** During laparoscopy monopolar cautery increases the risk of unrecognized lesions to intra-abdominal organs, particularly the bowel.
*** The technical challenges of this approach have been facilitated by the use of a robotic-assisted procedure that improves the anastomotic repair
*** 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.
*** The peritoneal lining mirrors the light from the telescope, giving the transperitoneal approach better visibility than in the retroperitoneal route.
*** Horseshoe kidneys are a relative contraindication to the retroperitoneal approach as access to the UPJ from the posterior aspect is extremely difficult
*** Hypothermia during laparoscopy in all infants is caused by insufflation of a large amount of CO2 due to port leakage.
*** Bladeless optical trocars or open access for the camera port might be helpful for pediatric minimally invasive surgery in obese patients
** '''Newborns may be more suitable for open pyeloplasty since access to the ureteropelvic junction (UPJ) requires only a very small incision.'''
* '''Complications (3):'''
*# '''Prolonged urinary drainage postoperatively'''
*# '''Lack of improvement in renal function or improvement in washout'''
*# '''Occasionally, worsening hydronephrosis and diminished renal function post-operatively'''
*#* '''Such a situation may lend itself to a repair using endoscopic procedures or a repeat dismembered pyeloplasty'''

====== 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.'''