Preoperative Ureteric Stenting: Protecting the Kidneys and the Ureters Before Major Surgery
Introduction
The ureter is one of surgery’s most treacherous anatomical neighbors. A slender muscular tube — barely 4–5 mm in diameter — coursing retroperitoneally from kidney to bladder, it passes in intimate proximity to the ovarian and iliac vessels, crosses the pelvic brim, runs beneath the uterine artery (“water under the bridge”), and enters the bladder posterolaterally. In normal anatomy, an experienced surgeon can identify and protect it. In the distorted retroperitoneal landscape created by large tumors, dense adhesions, previous radiation, inflammatory masses, or pelvic organ cancer, the ureter becomes invisible — and vulnerable.
Ureteric injury during surgery remains one of the most serious and underreported complications in abdominal and pelvic surgery. Ureteral injuries are rare but serious complications in abdominal and pelvic surgery. Most ureteral injuries are iatrogenic and occur during gynecologic, colorectal, and vascular surgery. When a ureter is injured, the consequences cascade: urine leakage, fistula formation, obstructive uropathy, permanent renal loss, prolonged reoperation, and — in the worst cases — sepsis and death.
Preoperative ureteric stenting — placing a double-J stent endoscopically before complex retroperitoneal or pelvic surgery — addresses this risk directly. The research of Makhan Lal Saha and colleagues at the Institute of Post Graduate Medical Education and Research (IPGMER), Kolkata, published in the Urology Journal, has specifically examined whether preoperative stenting before surgery for retroperitoneal tumors causing obstructive uropathy improves both renal function and intraoperative ureteric protection.
The Problem: Retroperitoneal Masses, Obstructive Uropathy, and Ureteric Vulnerability
How Retroperitoneal Pathology Threatens the Ureter
The retroperitoneum — the space behind the peritoneum containing the kidneys, ureters, great vessels, adrenal glands, and lymph nodes — is the site of a diverse range of pathological processes that can simultaneously obstruct the ureter and make it technically hazardous to operate near:
Malignant causes of retroperitoneal ureteric obstruction:
- Retroperitoneal lymph node metastases (from colon, cervical, bladder, testicular, prostate cancers)
- Primary retroperitoneal sarcomas (liposarcoma, leiomyosarcoma)
- Directly invading pelvic tumors (cervical, rectal, bladder cancer)
- Lymphoma with bulky retroperitoneal disease
Benign causes:
- Retroperitoneal fibrosis (idiopathic or drug-induced)
- Large ovarian cysts or tumors with retroperitoneal extension
- Inflammatory bowel disease with retroperitoneal inflammation
- Post-radiation fibrosis
In each of these situations, the same pathological process that obstructs the ureter also distorts its normal anatomical course — making it impossible to reliably locate by standard anatomical landmarks during surgery.
The Dual Problem: Functional and Surgical
When a retroperitoneal mass compresses or invades a ureter, two distinct but related problems arise simultaneously:
The functional problem: Ureteric obstruction causes progressive hydronephrosis and renal impairment — the longer obstruction persists, the greater the irreversible parenchymal damage. Patients presenting for major surgery with chronically obstructed kidneys face higher operative risk from anesthetic agents, fluid management challenges, and reduced capacity to tolerate intraoperative blood loss.
The surgical problem: The distorted anatomy makes intraoperative ureteric identification difficult or impossible — creating the conditions for inadvertent ureteric injury during tumor resection, lymph node dissection, or pelvic dissection.
Preoperative ureteric stenting addresses both problems with a single intervention.
What Is Preoperative Ureteric Stenting?
The Double-J Stent: Anatomy and Function
A double-J stent (DJ stent, also called a ureteral stent) is a soft, flexible plastic tube approximately 26 cm long, with a coiled (“pigtail”) end that sits in the renal pelvis and another coiled end that sits in the bladder. The coils prevent migration in either direction.
The stent is placed cystoscopically — under direct vision, a guidewire is passed retrograde through the ureter, and the stent is railroaded over the wire under fluoroscopic guidance. The procedure typically takes 15–30 minutes under sedation or light anesthesia and can be performed as a day-case intervention.
Mechanisms of Benefit
Preoperative ureteric stenting confers benefits through several distinct mechanisms:
Decompression of obstructed kidney: The stent bypasses the obstructing lesion, restoring urine drainage from the renal pelvis to the bladder. This decompression reverses the hydrostatic pressure that has been damaging the renal parenchyma — allowing partial or complete functional recovery before surgery.
Tactile identification during surgery: Preoperative ureteral stent placement provides tactile feedback during difficult pelvic surgery. When the surgeon palpates the retroperitoneal tissue, the firm stent within the ureter provides a clearly identifiable landmark — a cylindrical structure that can be felt even when it cannot be seen through surrounding tumor, fibrosis, or inflammatory tissue.
Structural reinforcement: The stented ureter has slightly increased diameter and rigidity compared to the unstented ureter — making it marginally more resistant to inadvertent crush injury from clamps or retractors.
Early injury recognition: If a ureteric injury does occur despite stenting, the stent’s presence facilitates recognition — urine leak patterns around a stented ureter are more localizable, and the injury is more likely to be detected intraoperatively rather than postoperatively.
The Evidence: Does Preoperative Stenting Actually Prevent Ureteric Injury?
The Controversy in the Literature
The evidence for preoperative ureteric stenting as injury prevention is genuinely contested — a fact that makes Saha’s outcomes-focused study valuable:
Meta-analyses examining preoperative ureteral stenting in colorectal surgery have produced inconsistent results. Some studies show reduction in ureteric injury rates; others show no benefit. The inconsistency likely reflects:
- Heterogeneity in case complexity across studies — stenting may benefit high-risk cases more than low-risk ones
- Variation in surgeon experience — less experienced surgeons may benefit more from stenting
- Publication bias — institutions that use stenting routinely may not report injury rates rigorously
- The relatively low baseline incidence of ureteric injury — making adequately powered RCTs extremely difficult to conduct
The Case for Stenting in High-Risk Cases
Despite the controversy in lower-risk settings, there is broad consensus that preoperative stenting is justified — and likely beneficial — in high-risk cases characterized by:
| Risk Factor | Rationale for Stenting |
| Retroperitoneal tumor with ureteric involvement | Distorted anatomy; obstructed kidney benefits from decompression |
| Previous pelvic radiation | Radiation fibrosis obliterates normal tissue planes |
| Recurrent pelvic surgery (reoperation) | Adhesions from previous surgery distort ureteric position |
| Inflammatory/infective mass adjacent to ureter | Inflammatory infiltration makes dissection hazardous |
| Bulky pelvic lymphadenopathy | Ureter may be encased within nodal mass |
| Known or suspected ureteric involvement by tumor | Direct invasion makes standard identification impossible |
In the subset of patients with documented preoperative ureteric obstruction, stenting before major retroperitoneal surgery provides the dual benefit of renal function optimization and surgical safety — two benefits that compound each other: a patient with better preoperative renal function tolerates surgery better and recovers more rapidly.
The IPGMER Kolkata Study: Outcomes in Obstructive Uropathy Patients
The study by Saha and colleagues specifically examined patients with retroperitoneal tumors causing obstructive uropathy — a population where both the functional and surgical rationale for preoperative stenting are strongest:
Key findings in this population included:
- Preoperative stenting achieved meaningful improvement in serum creatinine before surgery in a significant proportion of patients — indicating partial functional recovery of obstructed kidneys
- Intraoperative ureteric identification was facilitated in stented patients — surgeons reported easier localization of the ureter during retroperitoneal dissection
- Ureteric injury rates were lower in stented patients compared to historical unstented cohorts
- Postoperative renal function outcomes were better in patients whose kidneys had been decompressed before surgery
Preoperative Stenting in Specific Surgical Contexts
Colorectal Surgery
Ureteric injuries in colorectal surgery most commonly occur during sigmoid colectomy, anterior resection, and abdominoperineal resection — the operations that require dissection in the pelvis where the ureter is closest to the operative field. The incidence of ureteric injury in standard colorectal surgery is approximately 0.3–1.5% — seemingly low but clinically devastating when it occurs.
Most colorectal surgery centers do not use preoperative stenting routinely but select it for high-risk cases: T4 tumors adherent to pelvic sidewall, locally recurrent rectal cancer, previous pelvic radiation, or cases where imaging suggests ureteric involvement.
Gynecological Surgery
Gynecological procedures account for approximately 50–75% of all iatrogenic ureteric injuries. The ureter is particularly vulnerable during hysterectomy, where it passes within 2 cm of the cervix and must be mobilized away from the uterine artery.
In advanced ovarian cancer — where bulky retroperitoneal disease may encase both ureters — preoperative bilateral stenting before cytoreductive surgery is widely practiced and supported by observational data showing reduced ureteric injury rates.
Vascular Surgery
Retroperitoneal vascular surgery — particularly aortoiliac bypass, aortic aneurysm repair, and iliac vessel procedures — operates in direct proximity to the ureters. Post-radiation cases and redo vascular surgery are particularly high risk for ureteric injury.
Complications of Ureteric Stenting: The Other Side of the Equation
Stent-Related Morbidity
Preoperative stenting is not without its own complications — a consideration that must be weighed against its protective benefits:
- Lower urinary tract symptoms (LUTS): the most common complaint; frequency, urgency, and dysuria from bladder irritation by the distal coil affect 40–80% of stented patients
- Flank discomfort: from the proximal coil in the renal pelvis, particularly on voiding when vesicoureteric reflux occurs through the stented ureter
- Urinary tract infection: stent-related bacteriuria and UTI increase with stent duration
- Stent encrustation: with prolonged indwelling time (> 3 months); relevant when surgery is delayed after stent placement
The timing between stent placement and surgery is important: stents placed more than 4–6 weeks before surgery show higher complication rates and may develop encrustation that makes them harder to remove.
Conclusion
Preoperative ureteric stenting occupies a well-defined role in the surgeon’s risk-reduction armamentarium — not as a routine precaution for all pelvic surgery, but as a targeted intervention for the high-risk cases where retroperitoneal distortion, ureteric obstruction, or both create conditions where ureteric injury is a genuine threat and renal function optimization is a meaningful preoperative goal.
The work of Makhan Lal Saha and colleagues at IPGMER Kolkata — studying outcomes specifically in patients with obstructive uropathy from retroperitoneal tumors — provides Eastern Indian institutional data confirming the dual rationale for preoperative stenting in this population: improved renal function before surgery and improved intraoperative ureteric identification. This evidence contributes to an international evidence base that continues to refine the selection criteria for preoperative stenting.
Your next steps as a patient, surgeon, or urologist involved in high-risk retroperitoneal or pelvic surgery:
- If you are a general, gynecological, or vascular surgeon planning a case with significant retroperitoneal distortion, involve a urologist in preoperative planning — the decision about stenting is most valuable when made collaboratively, with both surgical and urological perspectives on case-specific risk
- If preoperative imaging shows ureteric obstruction or hydronephrosis, request urology consultation before scheduling major surgery — decompression before the operation, not emergency stenting after ureteric injury, is the correct sequence
- Understand that stent placement itself requires informed consent — a significant proportion of patients experience meaningful LUTS during stenting that affects daily function, and this should be communicated before placement
- Plan stenting timing carefully — a 2–4 week interval between stent placement and surgery provides adequate time for renal function recovery without excessive stent indwelling time
- After stent placement, measure creatinine serially before surgery — improvement in creatinine confirms functional recovery and provides an objective endpoint; lack of improvement may indicate irreversible parenchymal damage that changes surgical risk assessment
- Ensure a formal plan for stent removal is documented before surgery — stents placed preoperatively are sometimes forgotten postoperatively; every patient who undergoes preoperative ureteric stenting should have stent removal scheduled as a mandatory post-surgical step