Management of Upper Urinary Tract Obstruction

Ureteropelvic junction obstruction

• See Ureteropelvic Junction Obstruction Section in Pediatrics Surgery of the Ureter Chapter Notes

Etiology

• Classified: congenital vs. acquired or intrinsic vs. extrinsic
• Most cases are congenital, but may only become clinically apparent much later in life
  • Congenital ureteropelvic junction obstruction (UPJO) usually results from intrinsic disease
    • UPJO in neonates is most frequently found as a result of maternal-fetal ultrasound
      • Many newborns diagnosed with hydronephrosis on are subsequently found to have UPJO
• Congenital causes of UPJO (5): SHAVA
  1. True ureteral Stricture
  2. High insertion found more frequently in the presence of renal ectopia or fusion anomalies
  3. Aberrant vessels (controversy persists). Regardless, the presence of crossing vessels has a detrimental effect on the success rates of endopyelotomy
  4. Kinks or Valves produced by infoldings of the ureteral mucosa and muscularis
  5. Aperistaltic segment
• Acquired causes of UJPO (5): CRIIBS
  1. Cancer
  2. Vesicoureteral Reflux; can lead to upper tract dilation with subsequent elongation, tortuosity, and kinking of the ureter
  3. Post-Inflammatory or postoperative scarring or Ischemia
  4. Benign lesion (e.g. fibroepithelial polyps)
  5. Stones

Diagnosis and Evaluation

History and Physical Exam

• History
  • Signs and Symptoms§
    1. Periodic abdominal pain (loin pain), usually after diuresis
    2. Vomiting
    3. Recurrent pyelonephritis
    4. Fever
    5. Uncommonly, abdominal mass, or hematuria secondary to infection

Imaging

• Performed to determine the anatomic site and functional significance of an apparent obstruction
• Diuretic renography
  • Commonly used for diagnosing both UPJ and ureteral obstruction
  • Most commonly used agent in renogram studies is technetium 99m mercaptoacetyltriglycine (99m Tc-MAG3), especially in the pediatric population§
    • In the adult population, other agents can be used, such as diethylenetriamine pentaacetate (DTPA)
  • Provides quantitative data regarding differential renal function and obstruction, even in hydronephrotic renal units (see Pathophysiology of UUT Obstruction Chapter Notes for nuclear imaging details)
    • In general, kidneys with < 15% differential function are nonsalvageable in adults (Chapter 48 suggests <10%).
      • If the potential for salvageability of function is still unclear, an internal stent or percutaneous nephrostomy may be placed for temporary relief of obstruction and renal function studies subsequently repeated

Management

• Options:
  • Observation
    • If patient is asymptomatic and the physiologic significance of the obstruction seems indeterminate, careful observation with serial follow-up renal scans is appropriate
  • Intervention (4):
    1. Decompression (stent or nephrostomy tube)
    2. Endourological procedures (balloon dilation or endopyelotomy)
    3. Pyeloplasty
    4. Ureterocalycostomy
• Indications for interventions for UPJO (5): (similar to diversion for ureteric stone + HTN)
  1. Symptoms associated with the obstruction
  2. Stones
  3. Infection
  4. Renal dysfunction
  5. Causal hypertension

Endourologic procedures

• Options (2):
  1. Balloon dilation
  2. Endopyelotomy
• Advantages:
  1. Less invasive
  2. Reduced hospital stays and postoperative recovery
• Disadvantages (2):
  1. Higher risk of failure than pyeloplasty.
     • Patients should be counseled that the success rate of any endourologic approach may be less than that of formal reconstruction.
       • Success rates approach 85-90% for percutaneous endopyelotomy.
  2. Requires taking into account the degree of hydronephrosis, ipsilateral renal function, concomitant calculi, and possibly the presence of crossing vessels, whereas pyeloplasty (open, laparoscopic, or robotic) can be applied to almost any anatomic variation of UPJO
     • Moderate to severe hydronephrosis is most predictive of failure after percutaneous endopyelotomy
• Transplantation complications are particularly suited to endoscopic (antegrade or retrograde) management
• Approaches:
  • Retrograde balloon dilation alone
    • Long-term follow-up studies have shown a diminishing success rate over time
  • Endopyelotomy
    • Contraindications (3):
      1. >2 cm of obstruction
      2. Untreated UTI
      3. Untreated coagulopathy
    • Technique
      • Approaches: percutaneous antegrade or retrograde ureteroscopic
        • The main advantage of retrograde ureteroscopic endopyelotomy is that it allows direct visualization of the UPJ and assurance of a properly situated, full-thickness endopyelotomy incision without the need for percutaneous access
        • Percutaneous endopyelotomy remains appropriate for patients with UPJO and concomitant pyelocalyceal stones, which can be managed simultaneously.
      • Methods: can be done with an endopyelotome, holmium laser or cutting balloon catheter
        • Cutting balloon catheters have the potential to better dilate ischemic and fibrotic lesions resistant to conventional balloon catheter dilation[1]
        • Little evidence for significant differences in success among endopyelotomy techniques.
          • Differences lie in technical considerations and complications.
        • If using an endopyelotome or laser, a full-thickness lateral incision is made through the obstructing proximal ureter, from the ureteral lumen out to the peripelvic and periureteral fat
          • Incision should usually be made laterally because this is the location devoid of crossing vessels
      • A stent is placed across the incision and is left to heal.
        • No consensus as to the optimal stent size or duration after endopyelotomy
      • Postoperative care
        • Avoidance of strenuous activity for 8-10 days after the procedure
        • Once the stent is removed, that patient returns 1 month later for history and physical exam, urinalysis, and diuretic renography
        • For most adults, 2-3 year follow-up is justified
          • Studies indicate that even at 36 months some late failures are identified, but relatively few are identified at 60 months
      • Complications
        • Early
          1. Bleeding requiring transfusion
          2. Urinary leak
          3. Drainage-related complications
          4. Hydropneumothorax
             • Risk is increased if upper pole access is used
        • Late
          1. Recurrent obstruction
             • Options if percutaneous endopyelotomy fails:
               1. Retrograde endopyelotomy
               2. Repeat percutaneous endopyelotomy
               3. Laparoscopic, robotic, or open operative intervention

Pyeloplasty

• Principles of UPJ anastomosis (5):
  1. Widely patent
  2. Watertight
  3. Without tension
  4. Heal over a stent
  5. Reconstructed UPJ should allow a funnel-shaped transition between the pelvis and the ureter that is in a position of dependent drainage
• Absolute contraindications (3):
  1. Untreated UTI
  2. Uncorrected coagulopathy
  3. Cardiopulmonary compromise unsuitable for surgery
• Before definitive surgical management, drainage of a kidney with UPJO is recommended only for infection associated with the obstruction or renal dysfunction resulting from obstruction in a solitary kidney or bilateral disease [suggesting no stent in renal dysfunction from single side obstruction if contralateral kidney fine]
• Technique
  • Approaches: transperitoneal, retroperitoneal, or anterior extraperitoneal
    • Transperitoneal laparoscopic approach is the most widely used method due to its associated large working space and familiar anatomy.
    • Retroperitoneal laparoscopic approach and anterior extraperitoneal approach rely on creation of a working space using manual or balloon dilation.
  • Methods: dismembered vs. non-dismembered
    • Dismembered pyeloplasty
      • Example: Anderson-Hynes pyeloplasty
      • Preferred by most urologists because this procedure is almost universally applicable to different clinical scenarios
        • Can be used regardless of whether the ureteral insertion is high on the pelvis or already dependent.
        • Permits reduction of a redundant pelvis or straightening of a tortuous proximal ureter
        • Anterior or posterior transposition of the UPJ can be achieved when the obstruction is the result of accessory or aberrant lower pole vessels
          • In the presence of crossing aberrant or accessory lower pole renal vessels associated with UPJ obstruction, a dismembered pyeloplasty is the only method to allow transposition of the UPJ in relation to these vessels.
          • If dismembered pyeloplasty is performed for the presence of crossing vessels, the renal pelvis is first transected circumferentially above the UPJ and the lateral aspect of the proximal ureter is spatulated. The renal pelvis and proximal ureter are then transposed to the opposite side of the crossing vessel and the ureteropelvic anastomosis is then completed with intracorporeal suturing techniques
        • Unlike the flap techniques, only a dismembered pyeloplasty allows complete excision of the anatomically or functionally abnormal UPJ itself
      • Dismembered pyeloplasty is not well suited to UPJO associated with (2):
        1. Lengthy or multiple proximal ureteral strictures
           • The spiral flap may be of significant value when both UPJO and a relatively long segment of proximal ureteral narrowing or stricture occur in the same setting
        2. Small, relatively inaccessible intrarenal pelvis
    • Non-dismembered pyeloplasty
      • Examples: Y-V plasty and flap pyeloplasty (Culp)
        • The Foley Y-V-plasty is designed for repair of a UPJ obstruction secondary to a high ureteral insertion.
        • Flap procedures are not appropriate in the setting of crossing vessels and when reduction of redundant renal pelvis is desired
  • The provision of external drainage from the site of surgical repair is absolutely necessary
    • Helps reduce risk of urinoma formation leading to possible disruption of the suture line, scarring, or sepsis
  • Post-operative care
    • The Foley catheter is usually removed 24 to 36 hours postoperatively, and the surgical drain is removed before hospital discharge if the drain output remains negligible.
      • If the drain output increases after the Foley catheter removal, the Foley catheter should be replaced for 7 days to eliminate urinary reflux along the stent in the treated ureter and decrease urinary extravasation at the ureteropelvic anastomosis.
    • Ureteral stent is typically removed 4-6 weeks later in an outpatient setting
    • Follow-up including the use of imaging studies such as diuretic renal scan is performed
  • Complications
    • Late
      • Persistent urinary drainage
        • Common after an unstented pyeloplasty is common, and will often require intervention.
        • When associated with a large blood clot, and likely edema at the anastomosis, the kidney will need early drainage until the bleeding resolves and edema improves.
          • In children, this is best managed with a nephrostomy tube, as stent placement in a young infant would likely result in stent occlusion from the renal pelvic blood clot.
        • In the majority of cases not associated with an occlusive blood clot, the leak will resolve spontaneously, so observation is the best approach in the early postoperative period in these patients.
          • If the leak is persistent and not associated with a consolidated clot, it would most likely resolve with retrograde stent placement.
      • Recurrent obstruction
        • Most failures from laparoscopic pyeloplasty occur in the first 2 years.
        • Management
          • Options (2)
            • Repeat pyeloplasty (open surgery has been used as a salvage procedure after failed laparoscopic pyelopasty)
            • Endoscopic intervention (most patients can be managed

Ureterocalicostomy

• Indications (3):
  1. UPJO or proximal ureteral stricture is associated with a relatively small intrarenal pelvis
  2. To provide completely dependent drainage when the UPJ is associated with rotational anomalies such as horseshoe kidney
  3. Salvage technique for failed pyeloplasty

Recurrent obstruction after treatment

• An open or laparoscopic approach can be recommended to any patient in whom primary endourologic management has failed, and an endourologic approach in whom an open or laparoscopic repair has failed

Ureteral stricture disease

• Evaluation and treatment of ureteral strictures is essential to preserve renal function and rule out presence of malignancy

Etiology

• Classification: benign vs. malignant

Benign

• SIIRRII PUF (8):

1. Stones
2. Instrumentation, endoscopic
3. Infection (tuberculosis)
4. Renal ablation injury
5. Radiation
6. Ischemia (trauma, surgical dissection)
7. Idiopathic
8. PeriUreteral Fibrosis caused by abdominal aortic aneurysm or endometriosis
   • Endometeriosis
     • Most patients with ureteral obstruction associated with endometriosis are asymptomatic
       • Signs and symptoms may occur cyclically and include flank pain, dysuria, urgency, hematuria and frequent urinary tract infections.
     • Management
       • A trial of hormonal therapy using gonadotropin-releasing hormone agonists (Lupron) or medroxyprogesterone (Danazol) should be initiated for mild symptomatic obstruction when there is good preservation of renal function.
       • For more severe obstruction associated with significant periureteral fibrosis, surgical intervention to correct the obstruction, with or without hysterectomy and bilateral salpingo-oophorectomy, is recommended

• Hysterectomy accounts for over 50% of iatrogenic ureteral injuries
  • Most likely areas where the ureter can be occluded during hysterectomy (2):
    1. Level of the broad ligaments
    2. At the vaginal cuff and bladder trigone

Malignant

• Intrinsic: e.g. urothelial carcinoma
• Extrinsic: e.g. cervical cancer

Diagnosis and Evaluation

• The renal unit should be assessed for function before starting treatment because endourologic therapies require 25% function of the ipsilateral moiety to have reasonable success rates (Figure 49-34 suggests 20%)
• The presence of obstruction on CT can identify ureteral stricture disease, but antegrade or retrograde pyelogram, CT urography, or diagnostic ureteroscopy is necessary to define the location and length of the ureteral stricture

Management

• Options (3):
  1. Decompression
  2. Endourological procedures (balloon dilation or endoureterotomy)
  3. Surgical repair

Decompression

• Ureteral stent placement
  • Effective acutely in treating most ureteral strictures, particularly intrinsic ureteral strictures.
  • Patients with extrinsic ureteral compression eventually require percutaneous drainage or surgical management
  • The use of tandem ureteral stent placement (two parallel stents) has been shown to be effective in benign and malignant extrinsic ureteral obstruction
  • Placement of a ureteral stent in an obstructed system will result in decreased ureteral contractility
  • No clear consensus regarding the benefits of metallic stents

Endourologic procedures

• Best management for ureteral strictures < 2 cm with no previous intervention is an endoscopic approach
• Contraindications (1):
  1. Strictures >2cm because dilation alone is unlikely to be successful
• Options (2): balloon dilation or endoureterotomy
  • Balloon dilation
    • After 10 minutes of tamponade, the balloon is deflated and withdrawn. An internal stent is passed over a guidewire still in place, which is left indwelling for 2-4 weeks.
    • Follow-up diuretic renography is usually performed ≈1 month after stent extraction and at 6- to 12-month intervals thereafter
    • Success rates range from 50-76%, long-term outcomes are unfavorable
    • Best results obtained in patients with iatrogenic, non-anastomotic strictures such as those secondary to ureteroscopic instrumentation. In that setting, a success rate of 85% was achieved compared with a rate of 50% for anastomotic strictures
  • Endoureterotomy
    • The position for the incision is chosen as a function of the level of the ureter involved. In general
      • Lower ureteral strictures are incised in an anteromedial direction to stay away from the iliac vessels
      • Upper ureteral strictures are incised laterally or posterolaterally
    • The incision can be performed using a cold knife, a cutting electrode, or a holmium laser

Surgical repair

Ureteroureterostomy

• So-called end-to-end repair
• Bridges ureteral defect of 2-3cm
• Most appropriate for a short defects (2-3cm) involving the upper ureter or mid-ureter, either in the form of stricture or as a consequence of recent injury
  • Only short defects should be managed by end-to-end ureteroureterostomy because tension on the anastomosis almost always leads to stricture formation
  • Lower ureteral strictures are usually best managed by ureteroneocystostomy with or without a psoas hitch or Boari flap.
• Success rate for a tension-free, watertight ureteroureterostomy is > 90%
• Technique
  • In an open surgical approach, the choice of surgical incision depends on the level of the ureteral stricture
  • Place stay stitches: Use 3-0 silk to place stay stitches at 12 o'clock on proximal and distal ureter, a few cm away from the cut ends. This will facilitate orientation. These will be removed later.
  • Spatulate ureters: Use scissors to spatulate both ureters for 1-1.5 cm. Spatulate proximal ureter at 6 o'clock and distal ureter at 12 o'clock, using the silk stay sutures to guide orientation.
  • Posterior anastomosis: Use 4-0 absorbable monofilament suture (e.g. monocryl or PDS) to take an outside-in bite on proximal ureter at one corner of cut apex at 6 o’clock and then take corresponding inside-out bite on distal ureter just lateral to 6 o’clock. Tie stitch, cut tail, and place needle on rubber-shod clamp. Repeat bite on opposite side of cut apex at 6 o'clock and place needle on rubber-shod clamp.
  • Insert double J stent. Advance guidewire through proximal ureter into renal pelvis. Advance double J stent over guidewire and remove wire when stent in renal pelvis (meets resistance). To pass the distal end of the stent into the bladder, cut a side hole in the stent, and then pass the floppy end of the wire into the bladder and the firm end of the wire through the distal end of the stent and through the previously cut hole in the midportion of the stent. Advance the stent over the wire into the bladder and remove the wire.
  • Anterior anastamosis: Use 4-0 absorbable monofilament suture (e.g. monocryl or PDS) and place a U stitch at 12 o’clock: take an outside-in bite at 12 o’clock on the proximal ureter followed by inside-out bite on distal ureter just lateral to 12 o’clock apex, then outside-in bite on distal ureter on contralateral side of 12 o’clock apex, then corresponding inside-out on the proximal ureter. Tie this down, cut needle, and leave each suture side long.
  • Complete anastamosis: Use previous 4-0 absorbable monofilament sutures on shods and run each stitch anteriorly. Consider backhand for first bite at on corners. Once completed to 12 o'clock, tie to long tails from U suture. Cut tails.
    • If tissue quality is tenuous, interrupted anastomosis is recommended
      • Interrupted anastomosis allows more precise closure and ensures that the entire repair is not in jeopardy if a single area becomes compromised because of poor tissue quality, delayed ischemia, or an inadequate bite during the suturing.
      • With interrupted anastomosis, keep tail long as handles for subsequent stitch and cut them after stitch next to it is placed.
  • Remove silk stay sutures.
  • Insert surgical drain
  • Postoperative care
    • Foley catheter is usually left indwelling for 1 to 2 days.
    • Surgical drain may be removed if there is minimal output for 24 to 48 hours.
      • If the surgical procedure is not performed entirely in a retroperitoneal manner, it is important to determine the nature of the fluid from the surgical drain by checking the creatinine level of the fluid. If there is no urinary extravasation, the drain can then be removed.
    • The double-J ureteral stent is usually removed 4-6 weeks postoperatively

Ureterocalycostomy

• Ureteral stump is sewn end-to-side into an exposed renal calyx
• Rarely used; used where there is profound damage to the renal pelvis and UPJ

Ureteroneocystotomy

• Appropriate for injury or obstruction affecting 3-4 cm the distal of the ureter
• Bridges ureteral defect of 4-5cm
  • After adequate proximal ureteral mobilization, direct ureteroneocystostomy is performed only if a tension-free anastomosis is possible. Otherwise, a psoas hitch or Boari flap should be used as an adjunct.
• Technique:
  • Approaches: intravesical, extravesical, or through a combination of the two
  • Anastomosis can be tunneled or non-tunneled
    • A direct, non-tunneled anastomosis may be performed if postoperative reflux is acceptable
      • In a retrospective review, no significant difference in the preservation of renal function or risk of stenosis was found between refluxing versus anti-refluxing procedures. However, it is unclear if a non-refluxing anastomosis increases the risk of pyelonephritis in an adult patient
  • Extravesical ureteroneocystomy[2]
    • Cystotomy: Use cautery to make 1-1.5 cm vertical incision on anterior surface of bladder. Use 4-0 chromic to take inside out bites at 4 quadrants of the cystotomy. Apply snaps to these.
    • Spatulate ureter. Use scissors to spatulate the ureter for 1-1.5 cm at 6 o'clock.
    • Cephalad vesicoureteric anastomosis. Use 3-0 absorbable monofilament suture (e.g. monocryl or PDS) to take an outside-in bite on the bladder at the cephalad aspect of the cystotomy and then inside-out on one side of 6 o'clock apex of distal ureter. Use another 3-0 absorbable monofilament suture (e.g. monocryl or PDS) and repeat on contralateral side of cephalad aspect of cystotomy. Tie these down, cut end without needle, place needle end on shod.
    • Insert double J stent. Advance guidewire through ureter into renal pelvis. Advance double J stent over this, remove guidewire , and allow distal curl to fall into bladder.
    • Caudal vesicoureteric anastomosis. Use 3-0 absorbable monofilament suture (e.g. monocryl or PDS) and place a U stitch at 12 o'clock of ureter to caudal aspect of cystotomy: take an outside-in bite at 12 o'clock on the ureter followed by inside-out bite on caudal aspect of the cystotomy, then outside-in bite on caudal aspect of the cystotomy just opposite to previous bite, then inside-out on the opposite side at 12 o'clock on the ureter. Tie this down, cut needle off, and leave suture side long.
    • Complete vesicoureteric anastomosis. Use previous 3-0 absorbable monofilament sutures at apex and run each stitch distally. First bite is outside-in on ureter, second bite is backhand inside-out on bladder. Then subsequent bites are forehand outside-in on ureter, inside out on bladder. Once at the caudal end of anastomosis, tie to previous long 3-0 vicryl U sutures. Cut sutures.
    • Insert surgical drain

Psoas hitch

• An effective method to bridge a defect of the lower third of the ureter.
• Bridges ureteral defect of 6-10cm (other source says 5-8cm[3])
  • Can provide up to 5 cm of additional length compared to simple ureteroneocystostomy
  • May be preferred over ureteroureterostomy in lower ureteral injuries because the tenuous ureteral blood supply might not survive transection.
  • A ureteral defect extending proximal to the pelvic brim usually requires more than a psoas hitch alone
• Contraindications (1):
  • A small, contracted bladder with limited mobility
• Technique[4]
  • Identify the ureter. The ureter can be identified medial to the medial umbilical ligament (contains obliterated umbilical ligament) or anterior to the bifuctation of the common iliac artery.
  • Mobilize the ureter. Encircle the ureter with a vessel loop to facilitate traction. Mobilize the ureter distally and proximally. Care must be taken to preserve the periureteric adventitial tissue with its inherent blood supply of the ureter. Ligate and transect the ureter distally, and if being performed for ureteric mass or fistula, ligate and transect the ureter proximally above area of concern. For ureteric mass, send frozen section from the cut edge of the proximal ureter. Place a stay suture at 12 o'clock to facilitate orientation.
  • Mobilize the bladder. Fill the bladder with 200-300 mL of saline via the foley catheter. Dissect the peritoneum off the bladder. Depending on the length of the remaining proximal ureter, further bladder mobilization can be obtained by dividing the median umbilical ligament (urachus) and ipsilateral medial umbilical ligament. Additional mobility can be achieved by dividing the contralateral superior vesical artery.
    • Aim is to allow a tension-free fixation of the bladder to the psoas muscle at least 2-3cm above the common iliac vessel.
  • Cystotomy: Place two stay sutures, 4-5cm apart, in a oblique orientation such that the medial stay suture is more superior. Make a 4-5cm oblique incision between the stay sutures.
  • Evaluate bladder tension: Use index finger inside the open bladder to elevate the ipsilateral most cranial aspect of the bladder. Check if the raised flap easily reaches the intended point of fixation at the psoas muscle. If the bladder cannot be brought to the psoas muscle without tension, the oblique bladder incision is extended to obtain a longer bladder flap.
  • Fixation of bladder to psoas: Use two to three 3-0 absorbable monofilament sutures to take whole detrusor muscle thickness without mucosa and placed preferentially through the tendon of the psoas muscle above the common iliac artery and the femoral branch of the genitofemoral nerve.
    • Care should be taken to avoid injury to the genitofemoral nerve and the femoral nerve
  • Ureteroneocystotomy.
  • Insert stent.
  • Bladder closure.
  • Insert surgical drain
• Complications
  • Occur uncommonly
  • Early
    • Nerve injury
      • Femoral nerve is most likely to be injured during a psoas hitch
    • Bowel injury
    • Iliac vein injury
    • Urosepsis
  • Late
    • Urinary fistula
    • Ureteral obstruction
• Relative to the Boari flap, the advantages of psoas hitch include:
  1. Increased technical simplicity
  2. Decreased risk of vascular compromise
  3. Decreased risk of voiding difficulties

Boari flap

• A pedicle of bladder is swung cephalad and tubularized to bridge the a 10-15-cm gap to the injured ureter [Campbell's table says 12-15cm but text says 10-15cm]; a spiraled bladder flap can reach the renal pelvis in some circumstances, especially on the right side. Care should be taken to ensure adequate vascular supply to the flap
• A small bladder capacity is likely to be associated with difficult or inadequate Boari flap creation, warranting consideration of alternative methods in the preoperative surgical planning
• The ratio of flap length to base width should be ≤ 3:1 to help minimize flap ischemia

Renal descensus

• Renal mobilization can provide additional length to bridge a defect in the upper ureter or decrease tension on a ureteral repair
• Bridges ureteral defect of 5-8cm
• After entry to the Gerota fascia, the kidney is completely mobilized and rotated inferiorly and medially on its vascular pedicle. The lower pole of the kidney is then secured to the retroperitoneal muscle using several absorbable sutures. Up to 8 cm of additional length may be gained using this technique.

Transureterostomy

• Transposing the injured ureter across the midline and anastomosing it end-to-side into the uninjured ureter
• Most often performed as a secondary or delayed procedure
• Absolute contraindications (1):
  1. Insufficient length of the donor ureter to reach the contralateral recipient ureter
• Relative contraindications (5):
  1. History of nephrolithiasis
  2. Urothelial malignancy
  3. Retroperitoneal fibrosis
  4. Chronic pyelonephritis
  5. Abdominopelvic radiation
     • Any disease process that may affect both ureters represents a relative contraindication
• Reflux to the recipient ureter, if present, needs to be identified and corrected simultaneously. Therefore, a voiding cystogram should be performed preoperatively, in addition to any other imaging
• A tunnel under the sigmoid colon mesentery is created proximal to the inferior mesenteric artery to avoid ureteral tethering by this vessel; the donor ureter is then brought through the tunnel to the recipient side.
• The injured ureter becomes subsequently difficult to intubate or image with ureteroscopy through the bladder; ureteral access needs to be provided by a nephrostomy placed on the injured side.
• Caution is required while performing this procedure because it involves surgery on the uninjured, contralateral ureter with the theoretical risk for converting unilateral ureteral injury into bilateral ureteral injury. Instead of transureteroureterostomy, ileal interposition or ureteroureterostomy with renal mobilization, if necessary, are preferred.

Ileal ureter substitution

• Reconstruction of the ureter with urothelium-based tissue is most preferable because it is not absorptive and is resistant to the inflammatory and potentially carcinogenic effects of urine. Incorporation of other tissue is reserved for situations in which a defect cannot be bridged by other methods.
• Delayed ureteral repairs, especially when a very long segment of ureter is destroyed, can be performed by creation of a ureteral conduit out of ileum in much the same way that an ileal conduit is constructed to drain the urine after cystectomy.; appendix and fallopian tube have been found to be unreliable ureteral substitutes.
• When an isoperistaltic segment of ileum is directly anastomosed to the bladder, reflux and renal pelvic pressure increase are usually seen only during voiding. The retrograde transmission of intravesical pressure is dependent on the length of ileum segment used in interposition and the voiding pressure
• Only 12% of patients with normal preoperative renal function developed significant metabolic problems postoperatively, and preoperative renal function was identified to be an important prognostic factor
• Not recommended in the acute setting
• Contraindications (4):
  1. Baseline renal insufficiency (creatinine > 2 mg/dL)
  2. Inflammatory bowel disease
  3. Radiation enteritis
  4. Bladder dysfunction or outlet obstruction
• Before the surgical procedure, a full mechanical and antibiotic bowel preparation is often used
• The length of the ureteral defect is measured, and an appropriate segment of distal ileum is chosen. The segment should be ≥15 cm away from the ileocecal valve
• In the presence of a scarred or intrarenal pelvis, ileocalicostomy may be performed
• Patients with worsening metabolic abnormalities associated with a progressively dilating ileal ureter should be evaluated for vesicourethral dysfunction.
• Malignancy arising from an ileal ureter segment has been reported and it is recommended that regular endoscopic examination be performed starting at postoperative year 3 for early detection

Other interposition

• Short segments of small or large bowel are formed into a long, thin tube (Monti procedure)
• Appendix has also been used

Autotransplantation

• Generally, considered when the contralateral kidney is absent or poorly functioning or when other methods for ureteral substitution or repair are not feasible
• Final option before nephrectomy
• Not recommended in the acute setting

Ureteroenteric anastomotic stricture

• Rates of ureteroenteric anastomotic stricture after continent diversion is 3-25%, majority occur within the first 2 years
• Most patients with a long-term urinary conduit will have an element of chronic hydronephrosis that is not secondary to obstruction; obstruction suggested by a decrease in renal function or loss of reflux on a routine loopogram should prompt diuretic renography to quantitatively assess for functional obstruction
• Factors predicting stricture after ureteroenteric anastomosis:
  1. Technique used for ureteral dissection
  2. Segment of bowel used for the diversion
  3. Type of anastomosis performed
     • Risk of stricture is less in refluxing anastamoses compared to non-refluxing anastamoses and therefore the use of a reflexing anastamosis is preferred for continent reservoirs (note that there is no difference in risk of stricture for ureteroneocystotomy)
  4. Side of anastomosis
     • Higher incidence of stricture formation on the left
       • When performing an ileal conduit, the left ureter is brought underneath the sigmoid mesentery just overlying the aorta. The additional length and dissection needed on the left and the possibility of angulation around the inferior mesenteric artery may lead to increased risk of stricture on the left side

Management

• See Figure in Campbell's
• Antegrade endourologic management of ureteroenteric or ureterocolic strictures is preferred, unlike the management of ureteral strictures
• Strictures > 2cm or on the left are less likely to succeed with endourologic management
  • Endourologic success rate for
    • Strictures > 1cm is 6% vs. 50% strictures < 1 cm
    • Left sided-stricture 19% vs. 41% on the right
      • No difference was noted in sidedness with open repair
• Although long-term patency of minimally invasive procedures for ureteroenteric strictures is in the range of 50%, such approaches are still used as the initial intervention, reserving operative management for those patients in whom endourologic intervention fails and for patients with strictures > 1 cm
• When considering endoscopic incision of a left ureteroenteric stricture, the risk of hemorrhage is a consideration because the sigmoid mesentery can be in close proximity. This, taken with the lower success rates of all endoscopic approaches on the left side, supports serious consideration for primary repair when treating left ureteroenteric anastomotic strictures

Retrocaval ureter

• See Pediatrics Ureter Anomalies Chapter Notes

Questions

1. What are the causes of UPJO?
2. What are the indications for intervention in UPJO?
3. What are the options for intervention in UPJO?
4. How long is a stent kept for following pyeloplasty?
5. When should a ureterocalycostomy be considered?
6. What are the contraindications to endopyelotomy?
7. Persistence of which structure results in a retrocaval ureter?
8. What are the causes of ureteral stricture disease?
9. What are the management options for ureteral stricture disease?
10. What are the contraindications to transureterostomy?
11. What investigations are needed before considering transureteroureterostomy?
12. What are the contraindications to ileal ureter substitution?
13. What is the preferred approach (retrograde vs. antegrade) for the endoscopic management of ureteroenteric stricture?
14. What are the risk factors for failure of endourological management of a ureteroenteric anastamostic stricture?

Answers

1. What are the causes of UPJO?
   1. Congenital SHAVA
      1. True ureteral Stricture
      2. High insertion; found more frequently in the presence of renal ectopia or fusion anomalies
      3. Aberrant vessels (controversy persists). Regardless, the presence of crossing vessels has a detrimental effect on the success rates of endopyelotomy
      4. Kinks or Valves produced by infoldings of the ureteral mucosa and muscularis
      5. Aperistaltic segment
   2. Acquired CRIBS
      1. Cancer
      2. Reflux
      3. Ischemia
      4. Benign tumour
      5. Stones
2. What are the indications for intervention in UPJO?
   1. Symptoms
   2. Stones
   3. Renal insufficiency
   4. Infections
   5. Causal HTN
3. What are the options for intervention in UPJO?
   1. Observation
   2. Diversion (stent or nephrostomy tube)
   3. Endoscopic (balloon dilation, endopyelotomy)
   4. Pyeloplasty
   5. Ureterocalycostomy
4. How long is a stent kept for following pyeloplasty?
   1. 4-6 weeks
5. When should a ureterocalycostomy be considered?
   1. Small renal pelvis
   2. Dependent drainage in malrotated/ectopic kidney
   3. Failed pyeloplasty
6. What are the contraindications to endopyelotomy?
   1. Stricture > 2cm
   2. Active infection
   3. Uncontrolled coagulopathy
7. Persistence of which structure results in a retrocaval ureter?
   1. Posterior cardinal vein
8. What are the causes of ureteral stricture disease?
   1. Stones
   2. Instrumentation, endoscopic
   3. Infection (TB)
   4. Radiation
   5. Renal ablation injury
   6. Ischemia
   7. Idiopathic
   8. Periureteral fibrosis
9. What are the management options for ureteral stricture disease?
   1. Diversion
   2. Endoscopic
   3. Surgical
      1. Ureteroureterostomy
      2. Ureteroneocystotomy
      3. Psoas hitch
      4. Boari flap
      5. Renal descensus
      6. Transureteroureterostomy
      7. Ileal ureter
      8. Autotransplant
10. What are the contraindications to transureterostomy?
    1. Absolute: insufficient length of ureter
    2. Relative: history of stones, upper tract cancer, RPF, radiation, chronic pyelonephritis, any process that affects both ureters
11. What investigations are needed before considering transureteroureterostomy?
    1. VCUG to rule out reflux
12. What are the contraindications to ileal ureter substitution?
    1. Baseline renal insufficiency
    2. Bladder dysfunction or outlet obstruction
    3. Inflammatory bowel disease
    4. Radiation enteritis
13. What is the preferred approach (retrograde vs. antegrade) for the endoscopic management of ureteroenteric stricture?
    1. Antegrade
14. What are the risk factors for failure of endourological management of a ureteroenteric anastamostic stricture?
    1. Left sided stricture
    2. Stricture > 1cm

References

• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 49