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Prenatal Hydronephrosis

Prenatally diagnosed urinary tract dilation (UTD)

• Seen in 1-3% fetuses
• UTD grading systems: anterior/posterior renal pelvic diameter (APRPD), SFO, and UTD
• If SFU 1-2 (UTD A1) detected before 28 weeks, repeat US at 32 weeks
• If SFU 3-4 (UTD A2-3) detected before 28 weeks, repeat US every 4 weeks
• SFU resolution: 100% Grade 1 resolve within 30 months, 90% Grade 2 resolve within 48 months
• Antibiotic prophylaxis: no clear recommendation, can consider for P3 or high risk patients, can give until VCUG rules out reflux
• if concern for GU anomaly, obtain US 48hrs after birth

Postnatal hydronephrosis management

SFU Grade	If...	Then...
Grade 1-2	Newly diagnosed	Renal US in 1-6mo
Grade 3		Renal US in 1-3mo
Grade 4		Renal US + VCUG + renal scan in 1-3mo
Grade 1-2	Hydronephrosis resolved	Follow up PRN
	Hydronephrosis stable	Renal US q6-12mo until resolved or toilet trained
	Hydronephrosis after toilet training	Space out or stop renal US
Grade 3	Improving hydronephrosis	Renal US q6-12mo until resolved
	Stable hydronephrosis	Renal US q3-12mo until resolved
	Worsening hydronephrosis	VCUG + renal scan
Grade 4	Improving hydronephrosis	Renal US q3-12mo until resolved
	Stable hydronephrosis	Renal US q3-6mo
	Worsening hydronephrosis	Pyeloplasty
	Split function < 30-40%
	Worsening renal function
	UTIs
	Stable hydronephrosis + renal function > 40%	Pyeloplasty vs surveillance

Ureteropelvic junction obstruction (UPJO)

Principles and presentation

• Definition: any restriction to urinary outflow that if left untreated will lead to progressive kidney damage
• Most UPJO in neonates are due to intrinsic narrowing, whereas older children usually caused by lower pole accessory vessel
• VUR can cause secondary UPJO due to ureteral kinking, may improve spontaneously after VUR treatment (staged approach preferred)
• Contralateral UPJO seen in 10-40%
• Ureteral polyp: can cause obstruction and hematuria, seen in 0.5% patients undergoing pyeloplasty, perform ureteroscopic removal

Surgical management

• Indications: increasing hydronephrosis on US, worsening differential renal function, breakthrough infections, or flank pain
• Anderson-Hynes dismembered pyeloplasty: gold standard, spatulate ureter laterally and pelvis medially, excess ureter (usually stenotic portion) excised after reanastomosis
• Nondismembered pyeloplasty: variety of techniques - Foley Y-V plasty, Heineke-Mickulicz, vertical flap, spiral flap
• Ureterocalicostomy: rarely used, indicated for severely scarred ureter or repeat surgery
• Stenting: normally performed to prevent leak, but can be skipped (requires second anesthesia for stent removal), warrants foley for 24-48hr to prevent reflux
• Success rates: 90-100% (symptom resolution, improved hydronephrosis, no need for reoperation)

Calyceal abnormalities

• Diverticulum: epithelial lined cavity with isthmus, usually asymptomatic but 40% present with stones, can follow with US if asymptomatic, can treat stones and ablate lining if symptomatic
• Hydrocalycosis: dilation of a major calyx, rare
• Megacalycosis: nonobstructive calyceal enlargement related to malformation of renal papillae, may also have increased number, usually asymptomatic
• Infundibulopelvic stenosis: dysmorphic kidney with degrees of stenosis, need treatment to protect renal function

Hydroureter

Neonatal hydroureteronephrosis

• Start antibiotic prophylaxis (amoxicillin 10-15mg/kg daily), treat for at least 6-12mo
• Obtain postnatal renal US 48hr after birth, bladder images will differentiate ectopic ureter vs megaureter vs ureterocele
• Examine for evidence of ureterocele
• VCUG recommended if bilateral hydroureteronephrosis or bladder/renal anomalies on renal US
• VCUG optional if unilateral hydroureteronephrosis and no bladder/renal anomalies on renal US
• Obtain VCUG to define anatomy prior to any interventions
• Obtain renal scan if ureteral dilation > 10mm, consider foley to optimize drainage

Megaureter

• Can be obstructing, refluxing, both, or neither
• Primary obstructed megaureter (POM): likely due to distal adynamic segment towards UVJ, may present with UTI, pain, or hematuria
• Most nonrefluxing megaureters < 10mm diameter resolve spontaneously with antibiotic prophylaxis along
• Antibiotic prophylaxis: start immediately after diagnosis
• Surgical indications: recurrent UTIs, worsening dilation, differential renal function < 40% or change of > 5% on sequential scans
• Surgical principles: stenotic ureter excised, megaureter straightened/tapered (plication or excisional tapering) with length/diameter ratio 5/1
• Urgent decompression can be performed with nephrostomy tube or cutaneous ureterostomy
• Outcomes: 90% success rates, complications include obstruction, relux, and persistent dilation
• Can consider UVJ balloon dilation with 2-6mo stent

Ureterocele

• Intravesical: entirely within bladder and above bladder neck
• Ectopic: some portion sits permanently at bladder neck or urethra
• Cecoureterocele: orifice is in bladder but ureterocele cavity extends submucosally into urethra
• Can prolapse as an interlabial mass, distinct from vagina
• Urgent management may require transurethral incision or nephrostomy tube
• Transurethral incision (TUI): no difference in technique outcomes, larger holes demonstrate greater reflux risk (0-50%), 78-97% success rates
• Observation: no evidence obstruction or UTI
• Upper pole heminephrectomy: nonfunctional dilated upper pole, no need for ureterectomy
• Common sheath reimplantation: refluxing lower pole and functional upper pole
• Ureteral reimplant: functional upper pole, non-refluxing lower pole
• End ureterostomy can provide temporary relief

Ectopic ureter

• Gender difference: ureter always enters proximal to male urethral sphincter (no incontinence), ectopic ureter may present as incontinence in females due to vaginal insertion
• Acute infection: consider nephrostomy tube or cutaneous ureterostomy
• Surgical management: reimplantation if single, ureteroureterostomy if duplicated, (hemi)nephrectomy if nonfunctional

Zinner syndrome

• Definition: ectopic ureter, seminal vesicle cyst, renal agenesis
• Initial evaluation obtain pelvic US in neonatal period, after puberty onset, or if new LUTS/pain develop
• Voiding symptoms: evaluation with uroflow and PVR, consider urodynamics if abnormal voiding pattern, patients with obstruction may benefit from cyst excision (versus patients with poor emptying)
• a-blockers: offer to patients with LUTS, SV cyst < 5cm
• Infection: manage with antibiotics/drainage, increases risk for infertility
• Surgical intervention: consider if pain, infection, or cyst size ≥ 5cm