Upper Urinary Tract Obstruction

Infundibular Stricture

Causes

• Congenital
• Acquired — post-PCNL (~2%)
• Inflammation
• Crossing vessel — Fraley syndrome

Indications for management

• Preserve renal function — progressive deterioration
• Relieve symptoms — pain, infections, stones

Treatment options

• Nephrostomy or DJ stent
• Balloon dilatation
• Endoscopic incision → incise lateral
  • Avoid incising the anterior or posterior wall — blood vessels run there
  • Depth of cut 2–3 mm
  • Success 60–80%
• Partial nephrectomy → if other methods fail
• Nephrectomy → if non-functioning kidney

Ureteropelvic Junction Obstruction (UPJO)

Causes

Category	Mechanism	Detail
Congenital	Intrinsic	Absent circular muscle — seen in infants
Congenital	Extrinsic	Crossing vessels — seen in children & adolescence
Acquired	—	Stones, infection, malignancy, VUR

Investigation

• Labs, urinalysis & culture
• Imaging:
  • Pediatric → US — ballooning of the renal pelvis
  • Adult → CT urography
• MAG3 (functional / drainage)
• RGP (retrograde pyelogram)

Indications for intervention — Pediatric

• Symptoms / infection
• Progressive hydronephrosis
• Split function < 40%
• Stones
• Consider nephrectomy in pediatrics if function < 10%

Indications for intervention — Adult

• Symptoms & impaired renal function, or progressive impairment, or stones, or infection
• Nephrectomy if function < 20% and symptomatic
• If in doubt → place DJ stent or nephrostomy, then repeat assessment

Treatment options — success rates

Option	Success
Nephrostomy or stent	—
Balloon dilatation	71%
Endopyelotomy	81%
Pyeloplasty	90%
Nephrectomy	if non-functioning & symptomatic

Cautions / contraindications to dismembered pyeloplasty

• (1) Small intrarenal pelvis
• (2) Long diseased ureteric segment > 2 cm

Alternatives by anatomy:

• Long segment → spiral (Culp) pyeloplasty
• Small renal pelvis → ureterocalicostomy
• High ureteral insertion → Foley Y-V plasty (do NOT use for a large redundant pelvis)

Endopyelotomy — technique & failure

• Full-thickness lateral incision from the lateral ureteral lumen out to the periureteric fat
• Most likely to fail if:
  • Stenosis > 2 cm
  • Crossing vessels
  • Ipsilateral kidney function loss (< 25% function)
  • Massive hydronephrosis

Ureteric Stricture

Risk factors

• Impacted stone
• Ureteroscopy / ureteral surgery
• Radiation
• Infection

Work-up

• Goal: determine whether the stricture impairs renal function, produces symptoms, or arises from malignancy
• CTU + renal scan + RGP
• Biopsy if suspicious for malignancy

Management

• Stent or nephrostomy
• Balloon dilatation
• Endoureterotomy
• Surgical repair
• Nephrectomy → symptomatic, non-functioning

Balloon dilatation

• Diameter 12F–30F, time 30 s to 10 min
• Place a stent afterwards
• Failure rate increases if:
  • Ischemic etiology of the stricture
  • Length > 2 cm
  • Located in the mid ureter
  • Kidney function < 25%

Endoureterotomy & Endopyelotomy — Where to Cut

Location	Incision direction
UPJ	Lateral
Abdominal ureter	Lateral / posterolateral
Over common iliac vessels	Anterior
Pelvic ureter	Anteromedial
UVJ	12 o'clock

Special situations

• Transplant kidney ureteral stricture: do NOT excise the stenosis — ischemia will develop. Initial management is endoscopic.
• Uretero-intestinal anastomosis (ileal conduit): stricture is more common on the left ureter due to extensive mobilization — kinking occurs as the left ureter courses under the IMA.

Uretero-intestinal stricture — management algorithm

Stricture	Sub-condition	Management
Short < 1 cm, > 20% function	Right ureter	Endoscopic incision
Short < 1 cm, > 20% function	Left ureter	Consider formal repair
> 2 cm	< 20% function	Nephrectomy
> 2 cm	> 20% function	Formal repair

Retrocaval (Circumcaval) Ureter

• Embryology: persistence of the posterior cardinal as the IVC — ureter passes behind the IVC. Almost always right-sided. (preureteral vena cava > persistence of the subcardinal vein)
• Classic imaging: ureter loops medially behind the IVC — "reverse-J" / fish-hook appearance on IVU / CT urography.
• Type I (low loop, more common) — obstruction where the ureter crosses the IVC; Type II (high loop) — less obstruction.
• Treat only if symptomatic obstruction → ureteroureterostomy: divide ureter, transpose anterior to IVC, re-anastomose (open / lap / robotic).

Obstructed (Primary) Megaureter

• Definition: ureter > 7 mm distal diameter. Primary obstructive megaureter = aperistaltic juxtavesical segment (no reflux, no distal obstruction by stone/valve).
• More common in males, more often left-sided; up to ~25% bilateral.
• Work-up: US, VCUG (exclude reflux), MAG3 (function & drainage).
• Management:
  • Most resolve spontaneously → observe with serial US / renography.
  • Surgery if: declining function, breakthrough infections, worsening obstruction, or symptoms.
  • Repair = excision of aperistaltic segment + ureteral tapering / plication + reimplantation. In infants too small to reimplant, temporize with a stent or cutaneous ureterostomy.

Retroperitoneal Fibrosis (RPF / Ormond Disease)

• Fibro-inflammatory plaque encasing the aorta, IVC, and ureters → medial deviation + ureteric obstruction (classically mid-ureter, L3–L4).
• Idiopathic (~2/3); secondary causes: drugs (methysergide, ergot), malignancy, radiation, infection, IgG4-related disease.
• Imaging: CT/MRI shows a confluent peri-aortic plaque; the aorta is NOT lifted off the spine (vs. lymphoma). Biopsy if atypical to exclude malignancy.
• Management:
  • Relieve obstruction first → DJ stent or nephrostomy.
  • Idiopathic → corticosteroids ± steroid-sparing agents (tamoxifen, mycophenolate); IgG4-related responds to steroids.
  • Refractory / persistent obstruction → ureterolysis with intraperitoneal transposition or omental wrap. If ureterolysis fails → renal autotransplantation.
  • Stop the offending drug in secondary cases; treat the underlying cause.