Functional impairment of urine transport from the renal pelvis to the ureter.
About 1 in 1000 children.
May have bilateral PUJ obstruction.
More common in children with other urinary tract anomalies, such as VACTERL or multicystic dysplastic kidneys.
Theories behind aetiology in children:
- Intrinsic stenotic segment of ureter
- Congenitally aperistaltic segment of ureter
- Ureteric folds / tortuosity of proximal ureter (may resolve as child grows and ureter straightens)
- High PUJ insertion (?actually secondary phenomenon due to chronic obstruction of pelvis)
- Extrinsic obstruction from crossing lower pole vessel (found in about 30 % kids and adults undergoing pyeloplasty)
- Secondary obstruction secondary to VUR
- Anatomic abnormalities such as retrocaval ureter or horseshoe kidneys
Natural history & presentation:
The natural history of PUJ obstruction is children is variable and unpredictable.
Only approximately one third of children will go on to need surgery.
Many will either resolve, or never develop symptoms or lose function.
Cases may present with antenatal hydronephrosis on maternal ultrasound, with urinary tract infections, or with pain in a Dietl’s crisis. Rarely failure to thrive or hypertension can be attributed.
The paediatric kidney with PUJ obstruction is more susceptible to minor trauma.
Diagnosis of obstruction is confirmed with MAG3 renogram, after MCUG to exclude reflux.
Indications for surgical repair:
- Symptoms – pain, haematuria
- Recurrent UTIs
- Worsening renal function
- Worsening split renal function on renogram 5 – 10 % worse on progressive scans
- Split renal function < 40 %
- Increasing renal AP diameter on ultrasound
Surveillance
Annual ultrasound and bloods with bespoke MAG 3 renograms
Surgical options
Most common and accepted – Anderson-Hynes dismembered pyeloplasty.
Open vs laparoscopic – depends on experience and age.
Open
- Dorsal lumbotomy
- Limited exposure if unexpected findings
- Best for toddlers and infants without too much muscle
- Supra-12 – easily extended, more pain and worse cosmesis
- Anterior subcostal, staying extraperitoneal
Stent or no stent?
- Most surgeons prefer trans-anastomotic stent, although some advocate no stent
- Standard JJ vs transanastomotic nephro-ureteric stent which exits cutaneously and can be removed by pulling
Other options:
- Endoscopic management (balloon dilation etc) – generally not used in children
- Nephrectomy – if poorly/non functioning kidney (< 15 %)