Residency · Residency · Urology

Ureteral Stricture and UPJ Obstruction in Adults

Ureteral Stricture Disease

Etiology

In adults, ureteral strictures most commonly arise from iatrogenic causes. These include ureteroscopy, which carries a 1-3% risk of stricture formation, as well as open, laparoscopic, or robotic surgeries involving gynecologic, colorectal, or vascular procedures. Radiation therapy for cancers such as cervical, rectal, or prostate cancer can also lead to strictures. Prolonged ureteral stenting is another iatrogenic factor contributing to stricture development. Stone-related strictures occur due to impacted stones causing inflammation or surgical injury during stone treatment. Inflammatory causes include infections like tuberculosis and schistosomiasis, as well as retroperitoneal fibrosis and endometriosis. Malignant strictures result from extrinsic compression or direct invasion by tumors, and malignancy must always be excluded when evaluating strictures. Congenital causes such as primary obstructive megaureter or ectopic ureter are less common in adults. Ischemic injury, often due to devascularization during surgery, represents the most critical mechanism underlying iatrogenic strictures.

Evaluation

Imaging plays a central role in evaluating ureteral strictures. A CT urogram helps identify the level, length, and cause of obstruction while ruling out malignancy. A MAG3 renal scan assesses differential renal function and drainage patterns. Retrograde pyelography remains the gold standard for defining stricture anatomy, providing detailed information on location, length, and caliber. If a retrograde approach is not feasible, an antegrade nephrostogram can be performed. Endoscopic evaluation with retrograde ureteroscopy allows direct visualization of the stricture and enables biopsy to exclude malignancy. Surgical planning depends on several key factors: the stricture’s location (proximal, mid, or distal ureter), its length (short defined as less than 2 cm versus long greater than 2 cm), the ipsilateral renal function, history of radiation exposure, and the patient’s comorbidities and prior surgical history.

<image>Retrograde pyelogram demonstrating a mid-ureteral stricture with proximal hydroureteronephrosis, and a normal contralateral ureter for comparison</image>

Endoscopic Management

Endoscopic treatment options include balloon dilation and endoureterotomy. Balloon dilation is most effective for short strictures less than 1 cm in length and those without ischemic etiology, achieving success rates of 50-70% in these cases. However, it performs poorly in radiation-induced or ischemic strictures. Endoureterotomy, performed with laser or cold knife, is best suited for short strictures under 1-2 cm that are not related to radiation. The procedure involves incising the stricture through its full thickness laterally, avoiding medial incisions near vessels to prevent injury. A ureteral stent is left in place for 4 to 6 weeks post-procedure. Success rates range from 55-75% in favorable strictures. Endoureterotomy is contraindicated for long strictures, radiation-induced strictures, or those caused by extrinsic compression.

Open/Robotic Reconstructive Options by Location

Distal Ureteral Stricture

For distal ureteral strictures, ureteral reimplantation (ureteroneocystostomy) is the gold standard. This can be performed using either refluxing techniques such as Lich-Gregoir or non-refluxing methods like Politano-Leadbetter, with success rates exceeding 90%. When the defect is larger, a psoas hitch procedure can be employed, wherein the bladder is mobilized and fixed to the psoas tendon to bridge gaps up to 5-6 cm. Additional length can be gained by dividing the contralateral superior vesical pedicle. The psoas hitch has a success rate greater than 95%. For even longer defects, the Boari flap technique creates a tubularized bladder flap to form a neo-ureter, suitable for defects up to 10-12 cm when combined with a psoas hitch. This requires adequate bladder capacity and also achieves success rates above 90%.

Mid-Ureteral Stricture

Short mid-ureteral strictures less than 2-3 cm with healthy surrounding tissue are best managed by ureteroureterostomy, which involves excision of the stricture and primary anastomosis. Both ends of the ureter are spatulated to create a wide, tension-free anastomosis over a stent, resulting in success rates over 90%. When ipsilateral reconstruction is not feasible, transureteroureterostomy (TUU) can be performed, connecting the injured ureter to the contralateral ureter. This requires a healthy recipient ureter and carries a risk of contralateral obstruction in less than 5% of cases.

Proximal Ureteral Stricture/UPJ

Proximal ureteral strictures and ureteropelvic junction (UPJ) obstruction are addressed in the subsequent section on UPJ obstruction. The standard surgical approach for UPJ strictures is dismembered pyeloplasty.

Long-Segment or Complex Strictures

For strictures measuring 3-6 cm, buccal mucosa graft ureteroplasty has emerged as a promising option. This onlay graft technique, analogous to buccal graft urethroplasty, is increasingly performed using robotic assistance and achieves success rates around 85%. Very long strictures exceeding 6-8 cm or pan-ureteral disease may require ileal ureter interposition, where an isolated ileal segment replaces the ureter. This technique can substitute the entire ureter but carries risks such as metabolic acidosis, mucus production, and recurrent infections, with success rates of approximately 80-85%. Appendiceal interposition is a less common option reserved for right-sided short defects. In complex cases, autotransplantation of the kidney to the ipsilateral iliac fossa can be performed as a salvage procedure, allowing direct ureteroneocystostomy with a short ureter.

<image>Surgical technique diagrams showing psoas hitch, Boari flap, and ileal ureter interposition for ureteral reconstruction at different levels</image>

UPJ Obstruction in Adults

Pathophysiology

UPJ obstruction in adults typically results from an intrinsic aperistaltic segment of the proximal ureter at the ureteropelvic junction, which is the most common cause. Extrinsic factors include a crossing lower-pole renal vessel, present in 20-30% of adult cases, which can compress the UPJ. A high ureteral insertion on the renal pelvis is another anatomical variant that may contribute. UPJ obstruction may present de novo in adulthood or represent previously undiagnosed congenital UPJ obstruction.

Clinical Presentation

Patients often experience intermittent flank pain, which may be triggered postprandially or after a fluid bolus, a phenomenon known as Dietl crisis. Stone formation can occur in the obstructed system, and hydronephrosis may be discovered incidentally on imaging. Other presentations include urinary tract infections or hematuria.

Diagnosis

CT urography reveals hydronephrosis with a dilated renal pelvis and an abrupt transition at the UPJ, while the ureter distal to the obstruction remains of normal caliber. A MAG3 diuretic renogram demonstrates delayed drainage with a half-time (T1/2) exceeding 20 minutes and assesses differential renal function. Pyeloplasty is appropriate when function is well preserved, defined as greater than 40% differential function. In cases with severely impaired function below 15-20%, nephrectomy or observation may be considered. Retrograde pyelography can confirm UPJ narrowing if the diagnosis is uncertain. The Whitaker test, which measures the pressure-flow relationship across the UPJ, is rarely needed.

Surgical Management

Robotic/Laparoscopic Dismembered Pyeloplasty (Anderson-Hynes)

The gold standard treatment for UPJ obstruction is robotic or laparoscopic dismembered pyeloplasty, which achieves success rates of 95-98%. The procedure involves mobilizing the UPJ and renal pelvis, identifying any crossing vessels and transposing the ureter anterior to them if present. The narrowed UPJ segment is excised, and the proximal ureter is spatulated laterally. Redundant renal pelvis tissue is reduced in a reduction pyeloplasty. The ureter is then anastomosed to the dependent portion of the renal pelvis in a watertight, tension-free manner. A ureteral stent is placed and typically removed after 4-6 weeks, and a drain is left in place. The robotic approach is favored in adults due to excellent visualization and shorter recovery times.

Endopyelotomy

Endopyelotomy involves endoscopic incision of the UPJ, performed either antegrade or retrograde using a holmium laser through a ureteroscope or an Acucise cutting balloon catheter. Success rates range from 70-85%, which is lower than pyeloplasty. This technique is best suited for secondary UPJ obstruction following failed pyeloplasty or for short-segment obstructions. It is contraindicated in the presence of crossing vessels due to the risk of hemorrhage, significant loss of renal function, or high-grade obstruction. Pre-procedure CT angiography is essential to exclude crossing vessels before attempting endopyelotomy.

Laparoscopic/Robotic Non-Dismembered Techniques

Non-dismembered laparoscopic or robotic techniques such as Fenger-plasty (Y-V plasty) and Heineke-Mikulicz repair (longitudinal incision with transverse closure) are limited in application and generally reserved for short, kink-type UPJ obstructions. The dismembered technique remains more versatile and widely used.

<image>Robotic dismembered pyeloplasty steps: identification of crossing vessel, excision of UPJ segment, spatulation, and completed anastomosis</image>

Special Considerations

Radiation-induced strictures pose a significant challenge due to ischemic and fibrotic tissue changes, resulting in high recurrence rates with endoscopic treatments. Reconstruction using well-vascularized tissue such as an omental wrap or buccal mucosa graft is preferred. Retroperitoneal fibrosis can be steroid-responsive, especially in IgG4-related disease, or idiopathic. Management includes ureterolysis with omental wrapping and stenting as a temporizing measure. Biopsy is important to exclude lymphoma or desmoplastic processes. In cases of bilateral strictures, the more symptomatic or worse-functioning side is addressed first, often with staged reconstruction. Transplant ureter strictures require specialized management covered under transplant complications.

Clinical Pearls

It is crucial to always exclude malignancy in any ureteral stricture, particularly when there is no clear iatrogenic or inflammatory cause. The ureter’s blood supply is segmental and delicate; the proximal ureter receives medial blood supply from the renal artery, while the distal ureter is supplied laterally by the iliac and vesical arteries. Iatrogenic devascularization is the leading cause of strictures. The combination of psoas hitch and Boari flap techniques can bridge defects up to 12-15 cm in the distal to mid ureter. Buccal mucosa graft ureteroplasty represents an exciting advancement for mid-ureteral and proximal strictures, avoiding the morbidity associated with ileal interposition. For UPJ obstruction, CT angiography should always be obtained before endopyelotomy to exclude a crossing vessel, as this poses a risk of life-threatening hemorrhage. Robotic pyeloplasty remains the gold standard for adult UPJ obstruction with success rates of 95-98%, while endopyelotomy should be reserved for cases with favorable anatomy or secondary obstruction.

References

• AUA Guidelines on Ureteral Stricture Management
• EAU Guidelines on Upper Urinary Tract Urothelial Carcinoma and Urinary Diversion
• Benson AD, et al. "Ureteral stricture management." Urol Clin North Am. 2015;42(1):9-19.
• Zhao LC, et al. "Robotic ureteral reconstruction using buccal mucosa grafts." J Urol. 2018;199(6):1553-1557.
• Nakada SY, et al. "Management of UPJ obstruction." Campbell-Walsh-Wein Urology. 12th Edition.
• Kapoor R, et al. "Ileal ureter substitution: long-term results." J Urol. 2014.

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