Treatment and Workup for Hydronephrosis and Ureteral Stricture
Initial Diagnostic Workup
For hydronephrosis of unknown cause, MR urography (MRU) with and without IV contrast or MAG3 renal scan should be the primary imaging modality to identify the underlying cause and assess functional significance. 1
Imaging Strategy Based on Clinical Presentation
Asymptomatic unilateral hydronephrosis: MRU without and with IV contrast, MAG3 renal scan, or CT urography (CTU) with contrast are equivalent first-line options 1
Asymptomatic bilateral hydronephrosis or solitary kidney: MRU with contrast or MAG3 renal scan are preferred over CT to minimize radiation and provide functional assessment 1
Symptomatic hydronephrosis: Ultrasound with color Doppler, MRU with contrast, MAG3 renal scan, or CTU are all appropriate initial studies 1
Pediatric cases: MRU provides superior anatomic and functional detail for diagnosing ureteral strictures, which are frequently misdiagnosed on ultrasound and diuretic renal scintigraphy alone 2, 3
Stricture Characterization
Once a ureteral stricture is identified, determine the exact length and location before planning treatment, as this fundamentally dictates management options 4, 5. MRU excels at defining stricture length, location, and severity while simultaneously assessing renal function 2, 3.
Treatment Algorithm
Acute/Urgent Management
For infected obstructed systems (pyonephrosis) or symptomatic obstruction requiring immediate decompression, percutaneous nephrostomy (PCN) is the preferred initial intervention, particularly in septic or hemodynamically unstable patients. 1
PCN is superior to retrograde ureteral stenting when the patient is septic, hypotensive, or has failed retrograde access 1
For pregnant patients (≥20 weeks) with infected hydronephrosis, either retrograde ureteral stenting or PCN are appropriate options 1
In malignant obstruction with bilateral hydronephrosis and renal failure (GFR <15), retrograde stenting, PCN, or percutaneous antegrade stenting are equivalent alternatives 1
Definitive Treatment Based on Stricture Length
Short Strictures (<2 cm)
Endoscopic management with balloon dilation or laser endoureterotomy is appropriate for benign ureteral strictures less than 2 cm in length. 5, 6
Success rates range from 35-70% for endoscopic approaches 7, 5
Balloon dilation with or without stenting can be performed as initial therapy 6
Laser endoureterotomy provides an alternative minimally invasive option 6
Critical caveat: Endoscopic management has high failure rates for strictures >2 cm, and repeated endoscopic procedures may worsen stricture length and complicate subsequent reconstruction 5
Long Strictures (≥2 cm) or Failed Endoscopic Management
For ureteral strictures ≥2 cm or those that have failed endoscopic treatment, open surgical reconstruction should be performed rather than repeated endoscopic procedures. 4, 5
Surgical options include:
Simple stricture excision with end-to-end ureteroureterostomy: For focal mid-ureteral strictures with adequate ureteral length 4, 6
Ureteroneoimplantation (ureteral reimplantation): For distal ureteral strictures near the bladder 4, 6
Ureterolysis with omental wrapping: For extrinsic compression or radiation-induced strictures 4
Ileal ureter replacement: For extensive strictures where primary reconstruction is not feasible 4
Renal autotransplantation: For complex cases with extensive ureteral loss 4, 6
Urinary diversion: Reserved for radiation-induced strictures or cases where reconstruction has failed 6
Long-term success rates exceed 90% with appropriate surgical reconstruction, with significant complication rates <5% 4
Special Considerations
Radiation-Induced Strictures
Radiation-induced ureteral strictures are particularly challenging and often require urinary diversion rather than reconstruction due to poor tissue quality and high failure rates. 6
These strictures tend to be longer and more fibrotic 6
Endoscopic management has particularly poor outcomes in this population 6
Consider early urinary diversion to preserve renal function 6
Stone-Related Strictures
Patients with complicated ureteroscopy or severely impacted calculi (median size 1.15 cm) warrant close imaging follow-up after stone treatment due to risk of rapid renal deterioration from stricture formation. 6
60% of benign ureteral strictures in one series were caused by impacted stones 6
Ureteric complications during stone treatment (perforation, urinoma, guidewire fracture) significantly increase stricture risk 6
Obtain follow-up imaging 4-6 weeks post-procedure in high-risk cases 6
Post-Surgical Ureteral Injuries
For ureteral leaks or strictures after abdominal surgery, PCN decompression as primary management decreases reoperation rates and morbidity compared to immediate surgical repair. 1
PCN provides access for definitive treatment and may obviate need for repeated surgery 1
If retrograde stenting fails, interval PCN placement allows for secondary attempts at antegrade stenting across the injury 1
This approach is equally effective for renal transplant ureteral complications 1
Common Pitfalls to Avoid
Do not rely on ultrasound alone for diagnosing ureteral strictures, as they are frequently misdiagnosed as UPJ or UVJ obstruction 2, 3
Avoid repeated endoscopic procedures for recurrent strictures, as this worsens outcomes and complicates subsequent reconstruction 5
Do not delay imaging follow-up after complicated stone procedures or impacted calculi, as strictures can cause rapid renal deterioration 6
Consider patient life expectancy and comorbidities when planning treatment for malignant obstruction—chronic stent changes may be more appropriate than aggressive reconstruction in advanced disease 1, 6