Prof. Giacomo Novara — Urology, University of Padua
Ureteral Strictures
Aetiology, diagnosis, and reconstructive treatment
Ureteral strictures are almost always iatrogenic in origin. They represent one of the most demanding reconstructive challenges in urology: the ureter has a precarious segmental blood supply, and its repair requires surgical solutions that vary according to the location and length of the defect. The strategy depends on where the injury is, how long the defect is, and when it is diagnosed.
⚠️ Aetiology — almost always iatrogenic
In Western countries, ureteral trauma from external causes (stab wounds, gunshot injuries) is exceptional. The vast majority of ureteral injuries — and the resulting strictures — are the consequence of surgical procedures on adjacent organs.
Urological causes
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Ureteroscopy
The most frequent urological cause. Ranges from simple mucosal abrasion to complete ureteral avulsion (the most severe complication, ~0.1% of cases but with devastating consequences).
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Radical prostatectomy
Rare but possible. The pelvic course of the ureter exposes it during bladder dissection. Typically involves the distal ureter.
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Uretero-ileal anastomosis (neobladder)
Stricture of the uretero-intestinal junction, occurring years after surgery. Requires reimplantation of the ureter into the neobladder.
Non-urological causes — the most frequent
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Hysterectomy
The classic cause. The pelvic ureter runs only 1–2 cm from the uterine cervix. It may be transected, ligated, or devascularised during parametrial dissection.
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Anti-incontinence surgery (sling)
The needle or tape may damage the distal ureter during pelvic placement.
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Colorectal surgery
Sigmoid resection (diverticular disease, neoplasia), right or left hemicolectomy. The lumbar ureter may be involved when not identified pre-emptively by the surgeon.
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Pelvic radiotherapy
Post-radiation periureteral fibrosis. Dramatically worsens the prognosis of any subsequent surgical repair due to vascular damage to the surrounding tissues.
📌 Intraoperative prevention: identify the ureter before beginning difficult dissection. The easiest landmark is the crossing with the common iliac vessels — the ureter is always identifiable here. Once isolated, follow it distally while staying outside the periureteral fat. In high-risk procedures, a mono-J ureteral catheter can be placed the day before as a palpable intraoperative "flag."
🔬 Why ureteroureterostomy fails
The ureter has a segmental and precarious blood supply: small retroperitoneal vessels forming a subadventitial plexus. When the ureter is transected, this plexus is interrupted in the segment distal to the injury. Anastomosing a well-vascularised proximal stump to a hypoperfused distal one leads almost invariably to re-stricture.
This principle — devascularisation of the distal stump — is why ureteroureterostomy (direct end-to-end anastomosis of the two stumps) is avoided except in desperate situations. The correct approach is not to reattach what has been cut, but to use well-vascularised healthy tissue to bridge the defect.
🔍 Diagnosis
Intraoperative recognition
The ideal scenario: the injury is identified during the procedure and repaired immediately.
Postoperative recognition
1
Clinical suspicion
Fever, flank pain, absent bowel function, drain output that does not appear bloody. The classic triad of unrecognised ureteral injury in the first 48–72 postoperative hours.
2
Creatinine in drain fluid
The key test: creatinine is measured in the fluid collected from the surgical drain. Plasma creatinine is ~80–150 µmol/L; urinary creatinine is 5,000–15,000 µmol/L. If drain fluid contains 1,000–4,000 µmol/L, it is urine. Definitive differentiation in a matter of minutes.
3
CT urography with contrast
Localises the site of injury (pelvic, lumbar, or vesico-ureteral junction), quantifies upstream dilatation, and documents periureteral fluid collections. Gold standard for diagnosis.
4
Urinary diversion and "cooling off"
Once the injury is confirmed, the patient is not taken back to theatre urgently. Percutaneous nephrostomy is placed (unilateral for unilateral injury, bilateral if bilateral), recovery from the primary procedure is awaited, and definitive repair is planned at 6–8 weeks.
Possible outcomes of a ureteral injury
Frequent outcome
Ureteral stricture
The injured segment heals with fibrous scarring and stenosis. Urine accumulates upstream, causing progressive hydronephrosis and risk of renal damage.
In gynaecological surgery
Uretero-vaginal fistula
The ureteral injury communicates with the vagina. The patient reports continuous uncontrollable urinary leakage from the vagina, sometimes weeks after surgery.
🔧 Reconstructive treatment — by location and length
The choice of procedure depends on three variables: location (where along the ureter the stricture lies), length of the defect, and tissue status (irradiated or not).
Proximal / sub-pelvic strictureShort defect near the renal pelvis
As in ureteropelvic junction obstruction: resection of the strictured segment and direct pelvis-to-healthy-ureter anastomosis. Indicated when the stricture is short and close to the junction. Success rate slightly lower than native UPJ pyeloplasty.
🚫 Avoid
Ureteroureterostomy
End-to-end anastomosis of the two ureteral stumps. Very high re-stricture rate due to devascularisation of the distal segment. Reserved for cases where no other option is technically feasible.
Pelvic strictureBelow the iliac vessels — the most frequent site in iatrogenic injuries
If the mountain will not come to Muhammad, Muhammad must go to the mountain. If the ureter can no longer reach the bladder, bring the bladder up to the healthy ureter.
✅ First choice
Psoas hitch + ureteroneocystostomy
The devascularised distal stump is abandoned. The bladder is mobilised by dividing the contralateral pedicles → the bladder becomes highly mobile. The bladder wall is anchored to the psoas muscle (psoas hitch). The uretero-vesical anastomosis is reconstructed at the "horn" of bladder fixed to the iliopsoas. High success rate in non-irradiated tissue. Possible reduction in bladder capacity (pear-shaped deformity).
⚠️ Irradiated patient: pelvic radiotherapy damages tissue vascularity. The success rate of psoas hitch drops dramatically in irradiated tissue. In these cases, consider solutions using non-irradiated intestinal tissue (ileal ureter).
Lumbar strictureMid-ureteral segment — typically from ureteroscopy or colonic surgery
✅ First choice — up to 4–5 cm
Ureteroplasty with buccal mucosa graft (BMG)
The stricture is opened longitudinally (ureterotomy). A mucosal graft harvested from the inner lip or cheek is sutured as a "patch" over the opened segment, augmenting the lumen. Covered with periureteral fat or peritoneum to vascularise the graft. Internal DJ stent for 4–6 weeks. Robotic lumbotomic approach. Results at Padua: 90% long-term success rate.
⚠️ Right side — alternative
Appendiceal ureteroplasty
Available on the right side only. The appendix is opened along the antimesenteric border and sutured as a pedicled flap over the strictured ureteral segment, augmenting the lumen. Vascularised by its mesentery. Same rationale as BMG ureteroplasty.
🚫 Avoid if possible
Ureteroureterostomy
Same limitation as for proximal strictures: the distal stump is hypoperfused and re-stricture is the rule. Only in cases where no alternative exists.
Extensive defects — ureteral replacementWhen the stricture is too long for a patch or psoas hitch
✅ First choice if renal function is preserved
Ileal ureter
A segment of ileum is isolated on its mesentery, oriented isoperistaltically, and used as a conduit between the renal pelvis and the bladder. Requires adequate renal function (ileum reabsorbs urinary solutes). If the kidney is compromised, reabsorption causes hyperchloraemic metabolic acidosis.
⚠️ Last resort
Renal autotransplantation
The kidney is detached from its native position, repositioned in the iliac fossa (as in cadaveric renal transplantation), and anastomosed to the iliac vessels. This brings the kidney closer to the bladder, eliminating the need for a long ureter. Indicated when the ureter is unusable and renal function precludes an ileal ureter. Traditionally performed open; robotic variants are under development.
🦷 Buccal mucosa ureteroplasty — the reference technique at Padua
Rationale and technique
Oral mucosa (lower lip or cheek) is a stratified squamous epithelium particularly well suited to the urinary environment: resistant to moisture, rapid engraftment, easily accessible. The technique — borrowed from urethroplasty — has been applied to the ureter with excellent results.
Harvest: mucosal strip from the inner lower lip (preferred site at Padua) or cheek. Donor site morbidity is minimal.
Preparation: trimming of submucosal tissue, preservation of the lamina propria.
Application: longitudinal ureterotomy over the strictured segment; the buccal mucosa patch is sutured with absorbable suture, mucosa facing the ureteral lumen.
Coverage: peritoneal flap or periureteral fat over the patch to ensure vascularisation and mechanical protection.
Internal DJ stent for 4–6 weeks, then removed cystoscopically.
The main postoperative issue in these patients is recurrent urinary tract infections, manageable with targeted antibiotic prophylaxis. Long-term ureteral patency is excellent in the vast majority of cases.
❓ Frequently Asked Questions
During hysterectomy, the pelvic ureter — which runs only a few centimetres from the uterus — may be inadvertently injured. Depending on the extent of the damage, the affected ureteral segment may develop fibrous stenosis, which obstructs urinary drainage and causes kidney dilatation (hydronephrosis). The kidney itself is not diseased: it is suffering because it cannot drain. The injury is diagnosed with a CT scan and treated surgically, usually several weeks after recovery from the initial procedure.
The ureter has a very delicate blood supply, delivered by small vessels that form a fine plexus around its wall. When it is transected, the segment downstream of the injury loses this vascular supply. If the two stumps are reattached, a healthy, well-perfused segment is anastomosed to a hypoperfused one that tends to necrose and re-stricture. This is why alternative tissues are preferred — such as buccal mucosa, a mobilised bladder flap, or a bowel segment — all of which bring their own blood supply to the repair site.
Buccal mucosa ureteroplasty involves harvesting a small mucosal graft from the inner lip or cheek and using it as a "patch" to widen the narrowed ureteral segment, without removing it. Harvest from the mouth is a quick, safe procedure: the oral cavity heals within a few days and morbidity is minimal (some localised discomfort and swelling). This technique, performed by robotic laparoscopy, yields excellent long-term outcomes: approximately 90% of patients maintain ureteral patency without the need for further intervention.
No. The ureteral stent (DJ, double-J) is a temporary device left in place for the time needed for the anastomosis or repair to heal — usually 4–6 weeks. It is then removed as an outpatient procedure under brief cystoscopy. In particular cases, if healing is not yet complete or re-stricture risk remains, the stent may be left longer, but always with a planned removal date. A stent must never be forgotten: if left beyond 6 months it can calcify and become impossible to remove by simple cystoscopy.