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Ureteral Stricture

Ureteral stricture disease is pathologic narrowing of the ureteral lumen that obstructs urine flow and threatens the renal unit. Modern stricture disease is predominantly iatrogenic and stone-related rather than congenital, and the operative algorithm is dictated by four variables: location, length, etiology, and the integrity of the surrounding vascular bed.[1][2][3] Reconstruction is the durable treatment. Endoscopic options remain reasonable for a narrow set of short, well-vascularized strictures but carry substantially higher long-term failure rates.[1]

For congenital ureteropelvic-junction obstruction (the dominant proximal-stricture etiology in pediatrics and the most common primary indication for pyeloplasty), see UPJ Obstruction.

Etiology and Epidemiology​

Acquired benign ureteral strictures are dominated by stone disease and iatrogenic injury, with the distribution varying by referral population. Stone-related factors accounted for 85.2% in one 142-patient single-center cohort.[1]

CategoryMechanismNotes
Stone-relatedImpacted stone, stone granuloma, mucosal injury during ureteroscopyStricture in 2.9% after URS versus 1.5% after shock wave lithotripsy in a claims database (reported range 0.5–5%).[2][9] A 2024 meta-analysis pooled 1.9% after URS overall and 4.9% with impacted stones; a selected 21-patient series found 5/21 (24%) after removal of stones impacted for >2 months at mean seven-month follow-up.[61][42]
Iatrogenic — gynecologicHysterectomy, cesarean section, endometriosis surgery, prolapse repairLaparoscopic hysterectomy carries ~2× the ureteral injury risk vs open (OR 2.12)[5][6][7]
Iatrogenic — colorectalLAR, APR, sigmoidectomyRetroperitoneal dissection near the pelvic brim and sacral promontory
Iatrogenic — urologicPyeloplasty, ureteral reimplant, prior endoscopic surgery, thermal ablation of a renal massProlonged or high-power laser activation during ureteroscopy can raise irrigant temperature above experimental tissue-injury thresholds; reducing laser energy or frequency, shortening activation, and using room-temperature or cooled irrigation are proposed ways to limit temperature rise.[44] Percutaneous radiofrequency ablation of a renal mass close to the collecting system has been reported to cause UPJ obliteration and stricture, including a case ending in nephrectomy; cooled pyeloperfusion and assessment of the ablation zone's proximity to the collecting system were described during renal radiofrequency ablation; a microwave-ablation case report described hydrodissection with pyeloperfusion.[45][46][65]
Post-transplantIschemia at the ureterovesical anastomosis, BK virus, rejectionReported incidence 0.6–10.5%; approximately 81% of strictures were distal/ureterovesical in one selected cohort[30][31]
RadiationCervical, prostate, rectal cancer treatmentLong, ischemic, often progressive; poor candidates for endoscopic repair
Inflammatory / infiltrativeRetroperitoneal fibrosis, tuberculosis, endometriosis, schistosomiasisSchistosoma haematobium infection commonly involves the bladder and ureters in early disease; chronic infection can progress to ureteral fibrosis and stricture[51]
IdiopathicNo identifiable causeDiagnosis of exclusion

Iatrogenic ureteral injury and the operative reality the reconstructive surgeon manages:[5][6][7][8]

  • Ureteral injury complicates approximately 0.08% of gynecologic laparoscopy for benign indications.[6]
  • In a population-based hysterectomy cohort, 1,094/1,753 ureteral injuries (62%) were unrecognized intraoperatively. Compared with hysterectomies without ureteral injury, unrecognized injury was associated with urinary fistula (adjusted OR 124) and sepsis (11.9); corresponding adjusted ORs for recognized injury were 5.9 and 2.0. Unrecognized injury was also associated with acute renal insufficiency (adjusted OR 23.8).[8]
  • Across studies of gynecologic and colorectal surgery, intraoperative detection of ureteral injury was associated with lower odds of complication-management failure than postoperative detection (pooled OR 0.22).[5]
  • Prophylactic stents can aid ureteral identification in selected complex cases, but a protective effect is not established.[34][35] A 2024 review found no significant reduction in injury in three RCTs (3,277 patients; RR 0.90, 95% CI 0.49–1.65).[34][35]

These data are the case for early consult, intraoperative ureteral identification, and a low threshold for direct repair when called to the table. Operative detail is covered under Intraoperative Consultation.

Ureteral stents during pelvic brachytherapy serve a separate purpose from identification. In a retrospective review of 289 patients without pretreatment hydronephrosis who received high-dose-rate interstitial brachytherapy for cervical cancer, ureteral stricture occurred in 11 of 255 unstented cases and 0 of 34 cases with bilateral ureteral stents placed during the procedure. A companion comparative-dosimetry analysis in five cases found that contouring the ureters and applying dose constraints reduced the ureteral dose by a median of 22–31%, the proposed mechanism for a protective effect. This is a single-center, nonrandomized comparison.[49]

Pathophysiology​

In 31 resected benign ureteral strictures, histology showed inflammatory cell infiltration in 10/31 (32%), fibroplasia in 14/31 (45%), and hyalinization in 7/31 (23%).[4] Type I and III collagen content was greatest in the hyalinization group.[4]

Two practical points for the reconstructive surgeon:

  • Vascular supply influences endoscopic selection. In a retrospective series with at least two years of follow-up, balloon dilation succeeded in 33/37 (89%) short strictures with intact supply versus 2/5 (40%) short strictures with compromised supply. Among compromised-supply strictures, balloon dilation succeeded in 1/6 (17%) long strictures and 2/6 (33%) recurrent UPJ strictures, while endoureterotomy with temporary stenting succeeded in 17/19 (89%) selected cases.[12]
  • Indwelling stents are not benign. In a porcine model, 14 days of stenting caused urothelial-mesenchymal transition and fibrosis that had not fully recovered 7 days after removal. This is relevant when planning long-term diversion versus definitive repair.[10]

Risk factors for post-ureteroscopy stricture:[2][9] ureteral perforation (strongest predictor), impacted stone, large stone burden, embedded fragments, failed initial URS, preoperative hydronephrosis, prior ureteral intervention. In a 21-patient series of stones impacted for more than 2 months, 5/21 (24%) developed a stricture at the previous stone site at mean 7-month follow-up; four of the five had sustained perforation during earlier unsuccessful removal attempts.[42] Because obstruction can be silent, postoperative surveillance renal ultrasound is reasonable after ureteroscopic stone removal; after fragmentation of a radiopaque stone, a KUB film can be added to assess residual fragments.[43]

Clinical Presentation​

Acquired ureteral strictures present with flank pain, recurrent UTI, hydronephrosis on imaging, hematuria, or asymptomatic renal-function decline. As with UPJO, the failure mode is often silent: a strictured upper tract can lose function for months before producing symptoms, a strong argument for surveillance imaging after at-risk pelvic surgery, ureteroscopy for impacted stones, and pelvic radiation.[1][2]

Diagnostic Evaluation​

The reconstructive workup answers four questions: Where is it? How long? What's the function? Is the bed vascularized?

ModalityRoleNotes
Renal ultrasoundInitial detection / serial surveillanceQuantifies hydronephrosis only
CT urographyAnatomic workhorse in adultsIdentifies stone, mass, periureteral pathology, level of obstruction
MR urographyNoncontrast techniques can help when iodinated contrast is unsuitable; assess gadolinium use separatelyIn 149 patients with creatinine >2.5 mg/dL (259 renal units), MRU identified 54/65 ureteral strictures (83%) versus 18/65 (28%) with noncontrast CT.[11]
Retrograde pyelogramDefines stricture length, location, and the proximal/distal ureteral caliberUsually performed at the time of stent or definitive repair
Antegrade nephrostogramWhen retrograde access fails or a nephrostomy is already in placePairs naturally with antegrade endoureterotomy
Diuretic renography (MAG3)Quantifies split function and helps assess suspected obstruction in clinical and anatomical context.[60]Same interpretive thresholds as in UPJO

Retrograde and antegrade studies can be combined into an "up-and-down-o-gram," pairing an antegrade nephrostogram with a retrograde pyelogram to delineate both ends of a complex stricture for operative planning.[50]

Stricture length informs operative selection: endourological treatment had higher success for strictures ≤2 cm in one cohort, while a separate retrospective series treated selected longer strictures endoscopically.[1][12]

Rule out UTUC before treating a stricture-appearing lesion as benign. A calyceal, renal pelvic or ureteral filling defect on delayed contrast imaging raises concern for upper tract urothelial carcinoma. UTUC within the ureteral wall can mimic a benign stricture. AUA/SUO 2023 recommends diagnostic ureteroscopy with biopsy of identified lesions and selective upper-tract cytologic washing for suspected UTUC . Its discussion permits rare exceptions when other evidence clearly establishes the diagnosis or endoscopy would not change management.[47]

With an existing stricture or difficult access, AUA/SUO advises gentle dilation or temporary stenting and limiting aggressive dilation with access sheaths . If ureteroscopy is unsafe or impossible, selective washing or barbotage may be attempted, with pyeloureterography when good-quality CT or MR urography cannot be obtained .[47]

Management​

Principles​

  • Reconstruction offers durable repair. A single-center observational cohort reported 95.7% success with reconstruction versus 51.6% with endourological treatment, defining success as symptomatic improvement and radiographic relief of blockage.[1]
  • Endoscopic management is a selective option for short (≤ 2 cm), well-vascularized strictures with mild-to-moderate hydronephrosis. Recent onset may favor balloon dilation, but a strict <3-month cutoff is not established.[1][12][13]
  • The surgical principles are unchanged across all reconstructions: tension-free, watertight, well-vascularized, spatulated, stented.[15]
  • In one minimally invasive series, 4 of 6 recurrences occurred within 12 months and all within 36 months.[28] In a separate endourological cohort, median recurrence time was 51 months.[1] Long-term follow-up is advised after endoscopic treatment.[1][28]
  • Preoperative ureteral rest (no stent or nephroureteral tube across the stricture for at least 4 weeks, with nephrostomy drainage or no hardware) before robotic repair of proximal or middle ureteral strictures was associated with higher success in a multi-institutional retrospective series: 170/188 (90.4%) rested versus 31/40 (77.5%) not rested among 228 analyzed patients, at median follow-up of 23 versus 22 months. Buccal mucosa graft ureteroplasty was used in 39/188 (20.7%) versus 15/40 (37.5%), respectively.[48]

Endoscopic Management​

TechniqueReported successBest candidateCaveats
Balloon dilationPooled technical success 89% ± 4%; reported success 54% ± 14% at 6–12 monthsShort (≤ 2 cm), recent, intact vascular supplyWith compromised supply: 2/5 (40%) short strictures, 1/6 (17%) long strictures, and 2/6 (33%) recurrent UPJ strictures in a small series[12][13]
Endoscopic treatment (predominantly dilation; incision used in selected cases)Symptomatic and radiographic success was 51.6% of 95 benign cases; catheter-free status with stable renal function and satisfactory imaging at 36 months was 31/43 (72%) in a mixed-etiology cohort (14 benign), after excluding 13 initial access failures and three lost to follow-up. Success was higher for short stricturesShort benign stricture; antegrade preferred for upper-tract, retrograde for distalInferior to reconstruction for long or ischemic strictures[1][28]
Segmental metallic stents (Allium, Uventa, Memokath)After successful placement, pooled primary success (continued patency without reintervention) was 73% under 1 yr, 66% at 1–2 yr, and 39% beyond 2 yr (Allium 81% and 65% at 1–2 and >2 yr)Short strictures from point injury; frail or non-operative patients as maintenance drainageObstruction, migration, encrustation, UTI; high failure in long, radiated, inflammatory or thermally injured strictures[14][36]

Polymer stents and nephrostomy tubes need regular exchange and are prone to failure; in one 129-episode series of metallic stents for chronic ureteral obstruction, functional failure occurred in 19% of Resonance, 48% of Allium and 65% of Memokath insertions, with no Resonance failures for benign indications.[40] Extrinsic malignant obstruction and radiation strictures behave differently from short benign strictures, and reconstruction candidacy should be settled before committing to indefinite drainage.

Reconstruction by Location​

See the Upper Tract Reconstruction database for operative selection and repairs by location and length.

The choice of reconstruction follows the level of the stricture and the length of the defect.

Stricture locationShort (≤ 2–3 cm)Mid (3–8 cm)Long (> 8 cm) or panureteral
DistalUreteroneocystostomyPsoas hitch ± reimplantBoari flap ± psoas hitch
MidUreteroureterostomyBMG ureteroplastyBoari flap + psoas hitch (reach midureter); ileal ureter
ProximalUreteroureterostomyBMG ureteroplasty; ureterocalicostomy if intrarenal pelvisIleal ureter; renal autotransplantation
Panureteral——Ileal ureter (workhorse); renal autotransplantation (salvage)

Robotic reconstruction is now widely used for the full range of repairs, from ureteroureterostomy and reimplantation to Boari flap, BMG ureteroplasty, ileal ureter and autotransplantation; multi-institutional retrospective series report success above 90% for ureteroureterostomy and pyeloplasty and low high-grade complication rates.[3][16][17]

Distal Reconstruction — Reimplant, Psoas Hitch, Boari Flap​

A graded set of operations on the bladder, deployed by length of distal defect:[15]

  1. Ureteroneocystostomy (refluxing or anti-refluxing). This is the usual choice for the truly distal stricture. Reported success is high in retrospective series. For adult acquired injury or stricture, neither refluxing nor nonrefluxing reimplantation is universally preferred: balance reflux against anastomotic obstruction, bladder function and available ureteral length.[34]
  2. Psoas hitch. Used for defects that prevent tension-free reimplant. In Pugh et al.’s robotic psoas hitch, division of the urachus and contralateral medial umbilical ligament frees the bladder; its ipsilateral dome is fixed to the ipsilateral psoas tendon or muscle while avoiding the genitofemoral nerve.[53] The ureter is implanted into the cephalad bladder dome. Reported success is comparably high.
  3. Boari flap. Used for longer distal or middle defects when bladder capacity, mobility, and tissue quality permit; a three-patient laparoscopic series described an 8–12 cm defect range and treated strictures measuring 8.2–9.2 cm.[59] A separate single-center cohort reported a median flap length of 5 cm (IQR 4–8 cm).[54] A wide-based, anteriorly oriented bladder flap is tubularized over a stent and rotated cephalad to bridge the gap; combined with a psoas hitch when even more length is needed. In a prospective multicenter database of 50 robotic Boari repairs for mixed etiologies, 45/50 (90%) had no recurrent symptoms, imaging obstruction, or further surgery at median 15 months; the five observed failures occurred within two months.[37] A separate single-center retrospective cohort included 81 analyzed patients (56/81, 69%, responded to the postoperative symptom survey) and reported new persistent bladder medication in 12/81 (15%) and reflux-related flank pain in 9/81 (11%) at median 2.3 years.[54]

Mid-Ureteral Reconstruction​

  • Ureteroureterostomy. Used for short defects (≤ 2–3 cm) with mobile, healthy ureter. Spatulated end-to-end anastomosis over a stent. A four-center retrospective series reported greater than 90% success after robotic ureteroureterostomy at median 24-month follow-up.[16] In a separate single-center series of 22 robotic distal ureteroureterostomies for strictures of median length 1.5 cm, 20/22 (91%) had no recurrent obstruction or further intervention at median 54.6-month follow-up.[17]
  • Buccal mucosa graft (BMG) ureteroplasty. See below.
  • Transureteroureterostomy. Historically used for irreplaceable distal segments; rarely employed today given the durability of BMG and ileal ureter and the morbidity of jeopardizing the contralateral renal unit.

Buccal Mucosa Graft Ureteroplasty​

The most important technical advance in ureteral reconstruction of the past decade. BMG is a free graft that must acquire a blood supply from its recipient bed, rather than a vascularized flap. It avoids bowel harvest and is an option for selected complex strictures; the cited early cohorts chiefly concern proximal and midureteral disease.[18][19][20]

Technique:

  • Approach: robotic, transperitoneal, with the stricture exposed by mobilizing the ureter on its periureteral fat
  • Configuration: onlay graft (approximately 79% in a 19-patient cohort), with anterior longitudinal stricturotomy and the graft sutured as a roof, or augmented anastomotic repair when the back wall is also diseased.[19]
  • Vascular cover: the free graft requires a vascular recipient bed. Omental reinforcement was used in 18/19 repairs in one robotic cohort; a 14-patient open series covered the graft with perirenal or retroperitoneal fat without an omental wrap and reported 13/14 stricture- and ectasia-free without a stent at median 15 months.[19][66]
  • Stent and follow-up: Babbar et al. describe stent removal at 4–6 weeks with pyelography to assess patency; a four-patient robotic BMG series used diuretic renography at least three months postoperatively.[62][63]

Outcomes:

  • Multi-institutional 10-year cohort: 150/163 analyzed patients (92.0%) were free of additional intervention for recurrent stenosis at median 29-month follow-up (range 12–56 months)[21]
  • Earlier series report 87–90% at median follow-up 26–28 months[19][20]
  • Redo experience includes 18/54 (33.3%) patients after failed ureteral reconstruction in one series; in a later cohort, 77/163 (47.2%) had any prior stricture treatment.[20][21]
  • Median LOS 1–2 days for the robotic approach

Appendiceal flap ureteroplasty is a useful right-sided alternative when a normal appendix is in the field. It is used as an onlay or interposition and avoids harvesting a separate ileal segment or oral graft, but uses the appendix itself. A 14-patient multi-institutional series reported 92.9% patency (median stricture 4.75 cm; 71% onlay, 29% interposition).[3][38]

Ileal Ureter Substitution​

Reserved for panureteral or complex long-segment defects beyond the reach of native-ureter, bladder-based, or graft reconstruction, including extensive radiation injury, multiple failed prior reconstructions, and recurrent strictures from systemic disease.[22][23]

  • Technique: isolate the shortest well-vascularized ileal segment that reaches between healthy anastomotic sites without tension, tailoring length to defect and laterality; orient it isoperistaltically and join it proximally to renal pelvis or ureter and distally to bladder.[55]
  • Antireflux maneuvers: Xu et al. described fixing a 4-cm distal portion of retained upper ureter between the psoas muscle and interposed ileum. In a mixed series of 41 long-stricture or ureteral-defect cases and three ureteral-cancer cases, cystography showed no ileoureteral reflux among 43 followed patients (mean 69 months).[24]
  • Combined techniques for full-length defects: ileal segment plus Boari flap and psoas hitch to extend bladder reach[23]
  • Success approximately 83% (no further open intervention) at mean 4.4 years in a 46-patient single-institution series, with a 24% major-complication rate; mean stricture length 9.1 cm and 26% of cases radiation-related[22]
  • Morbidity unique to ileum: mucus production (chronic intermittent obstruction), hyperchloremic metabolic acidosis (particularly with impaired renal function), B12 deficiency over years, and bowel-anastomosis morbidity. Assess renal reserve and the health and availability of the proposed bowel segment; EAU advises avoiding ileal substitution with impaired renal function or known intestinal disease and checking serum chemistry after surgery for hyperchloremic metabolic acidosis.[34] Prior pelvic radiation requires evaluating the bowel actually selected.[34]

Renal Autotransplantation​

Salvage operation for the most extensive reconstructive failures: total ureteral loss after multiple prior attempts, panureteral radiation injury where ileum is unavailable, or extensive periureteral malignancy precluding orthotopic reconstruction.[25][27]

  • Renal function was preserved (no significant creatinine change) in a 51-patient, 54-procedure two-institution series with 2 graft losses; ureteral stricture was the indication in only 20%. Median follow-up was 21.5 months, and early Clavien IIIa or higher complications occurred in 14.8%[27]
  • Cold ischemia time was the only predictor of postoperative complications in that series.[27]
  • In an eight-centre comparison (15 RAIUR, 39 RAKAT), robotic kidney autotransplantation (RAKAT) and robotic ileal ureter (RAIUR) gave similar renal function and Clavien III+ complications (10% versus 13%); RAKAT had a shorter stay (5 versus 8 days) and fewer complications of any grade (31% versus 73%).[26] A 2026 meta-analysis (low certainty, 1,044 patients, 41 autotransplants) found success of 93.0% for ileal ureter and 87.8% for autotransplantation, not significantly different.[39] Choice follows anatomy, prior surgery, bowel and renal status, and surgeon experience[26][39]

Post-Transplant Ureteral Strictures​

Stricture in a transplanted ureter is a distinct problem because the ureter is short, end-arterial, and the recipient has comorbid CKD that limits diagnostic and operative tolerance.[29][30][31]

  • Incidence: estimates among kidney transplant recipients vary; published reports cite approximately 5–10%, while a single-center cohort observed 25 strictures among 1,167 recipients (2.1%) over mean 61.9-month follow-up.[31][41]
  • Distal/ureterovesical location accounted for approximately 81% of stenoses in one selected post-transplant treatment cohort; distal transplant ureteral ischemia is a recognized mechanism.[30]
  • Etiology: ischemia (dominant), technical factors, BK virus reactivation, acute or chronic rejection. In a single-center cohort of 1,167 transplant recipients with 25 strictures, prolonged cold ischemia (>435 minutes; OR 43.9, 95% CI 1.6–1238.8), acute rejection (OR 3.0, 1.1–7.4), and postoperative complications such as urine leak or infection (OR 112.4, 2.4–5332.6) were associated with later stricture; these estimates are imprecise.[41]
  • Post-transplant treatment. EAU renal transplantation guidelines recommend nephrostomy with antegrade pyelography for decompression and diagnosis .[64] They recommend reconstruction or endoscopic balloon dilation or laser incision for strictures <3 cm , and reconstruction for late recurrence or strictures >3 cm in appropriate recipients .[64] A 2024 systematic review reports good endourologic outcomes, particularly for short, early strictures.[29]
  • Definitive reconstruction achieved freedom from surgical failure in 26/30 (86.7%) selected post-transplant patients in a three-center retrospective series using mainly pyeloureterostomy to native ureter or ureterovesical reimplantation; the chronic-stenting group had an associated eGFR decline from 43.5 to 32.0 mL/min/1.73 m² between post-treatment baseline and last follow-up.[30]
  • Robotic transplant-ureter reconstruction, including single-port platforms, is feasible; a 27-patient single-center series reported success in 25/27 (92.6%) at median 15-month follow-up (median stay 3 days), with complications in 14/27 (52%), mostly Clavien II.[31][32]

Prevention​

During complex abdominal or pelvic surgery, EAU recommends visual identification of the ureter.[34] For a stable trauma patient whose ureteral injury is found during laparotomy, ACS trauma guidance recommends repair during that operation; gynecologic and colorectal studies associate earlier detection with fewer complications.[33][5][8]

  • Ureteroscopy: avoid perforation, minimize mucosal trauma at impacted stones, size the access sheath to the ureter, stent any procedure with intraoperative concern. A 2026 meta-analysis of 15 studies comprising 20,635 ureteroscopies for ureteral stones estimated a pooled perforation incidence of 1.89% (95% CI 1.11–3.19%; I² 93.5%); studies restricted to impacted stones reported 13.71%.[56] Injury can follow balloon dilation, forceful or misdirected stone manipulation, intracorporeal lithotripsy, or extraction devices. Once recognized, stop ureteroscopic manipulation and place a ureteral stent when possible; BAUS consensus advises a delayed retrograde study at about six weeks after successful stenting.[57][52] Completely extruded stones may be left in situ, while obstructing submucosal fragments should be removed after localization; in a 20-patient referral series, small embedded fragments were associated with subsequent stricture.[58] If a guidewire is already across the injury, a stent can still be placed and the case ended. AUA recommends managing an endoscopic ureteral injury with a ureteral stent and/or nephrostomy tube when possible, placing a nephrostomy tube when a stent cannot be placed or fails to divert the urine (Statement 13a; Recommendation, Grade C).[52]
  • Pelvic surgery: anatomic identification of the ureter at the pelvic brim and along the cardinal ligament; selective prophylactic stenting in high-risk gynecologic cases
  • Intraoperative recognition of injury is the single most important determinant of long-term outcome. When in doubt, obtain a retrograde study or inspect directly on the table
  • Indocyanine green (ICG) fluorescence was used intravenously in a 47-patient radical-cystectomy urinary-diversion cohort to assess distal ureteral perfusion and guide transection for ureteroenteric anastomosis; a 25-patient robotic ureteral-reconstruction series used intraureteral ICG to localize the ureter and stricture margins.[67][68]

For the acute consult on a recognized intraoperative ureteral injury, see Intraoperative Consultation.

See Also​

Podcasts​

Upper Tract Reconstruction
BackTable Urology, Ep. 43 (2022) · Lee Zhao, Aditya Bagrodia
backtable.com

Videos​

Robotic Repair of Transplant Ureteral Stricture: Treatment Algorithm
Ji E, et al. Urology Video Journal 2025 (CC BY-NC-ND 4.0)
Open source videoRead the article

References​

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