CLINICAL STUDY
Retrograde Transileal Conduit Stent Placement for Obstructed Uropathy—Success of Primary and Exchange Stent Placement Charles Ross Tapping, FRCR, James H. Briggs, FRCR, Mark W. Little, MBBS, Mark J. Bratby, FRCR, Jane Phillips-Hughes, FRCR, Jeremy P. Crew, FRCUrol, and Phil Boardman, FRCR
ABSTRACT Purpose: To assess the safety, success, and complications associated with retrograde ureteric stent insertion via the ileal conduit. Materials and Methods: The study population comprised 35 consecutive patients (17 men and 18 women; mean age, 55 y; age range, 40–75 y) requiring primary (20 stents) and exchange (70 stents) retrograde ureteric stent insertion via the ileal conduit over a 3-year period. Patient demographic data, procedural and technical data, and clinical follow-up data were collected. Results: Technical success was 90% (18 of 20) for primary stent placement and 100% (70 of 70) for stent exchange. There were two immediate complications (o 24 h) of sepsis and ureteric injury and one early complication (4 25 h but o 30 d) of sepsis requiring observation and medical management. Difficult procedures (defined as a fluoroscopy screening time 4 31 min) and technical failures were found to be associated with encrusted stents visualized on prior computed tomography (P ¼ .012), increased length of ileal conduit (4 20 cm) (P ¼ .023), and ileal conduit kink (o 90 degrees) (P ¼ .032). Only the occurrence of encrusted stents visualized on prior computed tomography (P ¼ .022) was associated with complications. Conclusions: Retrograde placement of ureteric stents via the ileal conduit is safe and effective. Retrograde stent placement should be considered the treatment option of choice for a first-time occurrence of obstructive uropathy at the ureteroileal anastomosis.
Ureteroileal anastomotic strictures are a well-known complication following ileal conduit formation after radical cystectomy, occurring in up to 16% of cases (1). Open surgical revision of the anastomosis is often technically challenging because of scar tissue surrounding the operative site. Interventional radiology techniques involving either retrograde or antegrade stent insertions are a robust alternative to open surgery. Antegrade stents enter the patient via the back and traverse the kidney and terminate preferably outside the ileal conduit. Retrograde stents enter the ileal conduit and terminate in the renal collecting system. Although placement of antegrade stents is technically easier, patients are
Department of Radiology (C.R.T., J.H.B., M.W.L., M.J.B., J.P.-H.), Oxford University Hospitals, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK; Departments of Radiology (C.R.T., J.P.-H., P.B.) and Urology (J. P.C.), Oxford University Hospitals, Churchill Hospital, Headington, Oxford, United Kingdom. Received August 12, 2013; final revision received February 10, 2014; accepted February 12, 2014. Address correspondence to C.R.T.; E-mail: [email protected] None of the authors have identified a conflict of interest. & SIR, 2014 J Vasc Interv Radiol 2014; XX:]]]–]]] http://dx.doi.org/10.1016/j.jvir.2014.02.013
usually more comfortable with retrograde placement via the conduit. The retrograde approach also offers advantages in terms of minimizing potential for complications from puncturing the kidney (bleeding) and infection (2). Long-term management of patients with stents placed across ureteroileal strictures requires regular stent exchange to prevent the stents from becoming encrusted and blocked, which would require emergency stent exchange or nephrostomy to prevent infection and urinary sepsis. Although this technique has been described previously, it can often be challenging to perform. No study has assessed predictive factors for success and aimed to improve success at retrograde stent placement via the ileal conduit. The purpose of this study was to assess the safety, success, and complications associated with retrograde ureteric stent insertion via the ileal conduit.
MATERIALS AND METHODS The review board at our institution classified this study as service evaluation and waived the need for formal approval and study consent. Over a 36-month period, 90 retrograde stents were inserted in 35 consecutive patients. All patients presenting to our unit for primary stent insertion or retrograde ureteric stent exchange via
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the ileal conduit were included. Primary stent insertion with subsequent exchanges during the study period was performed in 10 patients. These patients were included with a cohort of 25 patients who had previously had stents inserted either in our institution or within our region. Among the 25 patients who had previously had stents inserted, 4 patients had stents inserted surgically, 8 patients had stents inserted with a combination of antegrade and retrograde approaches with a two-stage or three-stage technique, and 13 patients had a de novo stent insertion in a retrograde manner as described in this article. In our institution, retrograde stents are not usually inserted endoscopically. The cohort comprised 17 men and 18 women with a mean age of 55 years (range, 40–75 y). Patient demographics are presented in Table 1. The initial indication for ileal conduit formation was malignancy in 70% of patients. The remaining 30% of patients were treated for benign disease, including neurogenic bladder dysfunction, bladder sphincter detrusor overactivity, and chronic inflammatory disease of the bladder.
Definitions and Endpoints Regarding ileal conduit anatomy, the distal end of the ileal conduit is the portion of the ileal conduit nearest the Table 1 . Patient Demographics Exchange Primary Stent Placement (n ¼ 10
(n ¼ 25 Patients)
P Value
56 (40–72)
63 (48–75)
.658
45:55 2.3
50:50 6.7
.852 .658
Mean length of
18
19
.023*
conduit (cm) ASA grade (I–VI)
I–II
I–II
.958
Diabetes (%)
35
45
.655
Hypertension (%) Ischemic heart
50 25
45 40
.099 .124
40
38
II
30
28
III IV
20 10
24 10
V
0
0
Male:female Mean age of conduit (y)
disease (%) Renal disease (%)† I
.991
ASA ¼ American Society of Anesthesiologists. Significant factor P o .05. † Renal disease classified according to creatinine clearance (CrCl) calculated by the Cockcroft-Gault formula using the National Kidney Foundation classification system: stage I, CrCl Z 90 mL/min/1.73 m2; stage II, CrCl 60–89 mL/min/1.73 m2; stage III, CrCl 30–59 mL/min/1.73 m2; stage IV, CrCl 15–29 mL/ min/1.73 m2; and stage V, CrCl r 15 mL/min/1.73 m2. n
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ostomy, and the proximal end is the portion nearest the ureteric anastomosis. Technical procedural success was defined as placing the retrograde ureteric stent via the ileal conduit with the proximal end of the stent in the renal collecting system and the distal end outside of or just inside the ileal conduit and it draining urine. If the ureteric stent was visible external to the patient, confirming urine drainage was simple and immediate. If the distal end of the stent remained within the conduit, confirmation of urine drainage was noted when urine was seen collecting within the drainage bag attached to the patient’s skin after the procedure. Clinical success was defined as continued drainage of urine via the stent until stent exchange (not requiring further interventional radiology or urologic surgery input) and associated reduction in urea, creatinine, and inflammatory markers after the procedure, if applicable. Complications were defined as per Society of Interventional Radiology (SIR) guidelines and were divided into major and minor complications (3). Fluoroscopy screening time was recorded. Procedures were divided according to fluoroscopy screening times of 0–15 minutes, 16–30 minutes, and 4 31 minutes. Numerous factors were studied in relation to complications and duration of fluoroscopy screening and included age of conduit, length of conduit (measured from procedural contrast loopogram), presence of stent-related calcification, kink (o 90 degrees), American Society of Anesthesiologists grade, diabetes mellitus, ischemic heart disease, hypertensive disease, and presence of renal disease.
Stent Placement
Patients) Age (y), mean (range)
’
General Retrograde Ureteric Stent Insertion Technique Primary Stent Placement. Computed tomography (CT) was performed before the procedure in all patients presenting with obstructive uropathy or sepsis. Patients received prophylactic antibiotics before the proce dure: amoxicillin/clavulanic acid 1.2 g administered intravenously (MA Holder, Aprilia, Italy) (4). In cases of preexisting penicillin allergy, ceftriaxone 750 mg administered intravenously was used (Stravencon Ltd, London, UK). Conscious sedation was achieved with intravenous administration of 3 mg midazolam (Mercury Pharma International Ltd, Dublin, Ireland) and 50 μg fentanyl (Halmeln Pharmaceuticals Ltd, Gloucester, UK) before the procedure. A 12-F Foley catheter (C.R. Bard, Inc, Covington, Georgia) was introduced into the ileal conduit, and the 10-mL balloon was inflated. Contrast material was injected to provide a road map of the conduit. Contrast material was injected via the catheter to reflux up the ureters, which helped to guide access. If contrast material failed to identify the distal ureters, a hydrophilic guide wire (Terumo, Tokyo, Japan) was inserted into a 4-F Berenstein II catheter (Cordis, Miami Lakes, Florida) (alongside the inflated Foley catheter). The wire and catheter were manipulated to the
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blind end (proximal end) of the conduit, and contrast material was injected via the catheter from the proximal end of the conduit. The perianastomotic injection of contrast material helped to increase identification of the ureters. The wire and catheter were engaged into the distal ureter and navigated to its proximal end. When the catheter and guide wire reached the renal collecting system, the guide wire was removed, and contrast material was injected to confirm location. An Amplatz Ultra Stiff guide wire (William Cook Europe, Bjaeverskov, Denmark) was inserted, and the catheter was removed. A 28-cm, 8-F Flexima ureteral stent (Boston Scientific, Natick, Massachusetts) was inserted over the wire, and the distal end of the stent was positioned to protrude out of the conduit to allow for easier exchange in 4–6 months. Exchange Stent Insertion. Antibiotics and sedation were prescribed as noted for primary stent placement. The distal end of the ureteric stent was ideally protruding from the ileal conduit (see further on if this was not the case) and was firmly grasped. A stiff wire was inserted under fluoroscopy control. The existing stent was carefully withdrawn. A 4-F Berenstein II catheter was exchanged over the stiff wire, and contrast material was injected to confirm the position and location within the collecting system. A new 28-cm, 8-F Flexima ureteric stent was inserted over an Amplatz Ultra Stiff guide wire after removal of the Berenstein II catheter, and the distal end of the stent was left protruding from the ileal conduit.
Modifications to Basic Technique if Heavily Calcified or Long Tortuous Ileal Conduit Heavily Calcified Stent Exchange. Occasionally, the distal end of the 28-cm, 8-F Flexima ureteral stent was found to have migrated inward and was not accessible from the ileal conduit. In these cases, the stent was snared with a 10-mm Amplatz GooseNeck Snare (ev3, Plymouth, Minnesota) (Fig 1a). Under fluoroscopy guidance, the distal end of the ureteral stent was withdrawn out of the conduit and grasped with a forceps. If the stent was heavily encrusted, the stiff end of a stiff hydrophilic wire (Terumo) was carefully inserted into the stent and advanced under fluoroscopy guidance. This wire was normally advanced through the blocked stent up to the proximal J tip. The hydrophilic wire was exchanged for a stiff wire (Amplatz Ultra Stiff guide wire), and an attempt was made to withdraw the stent. If withdrawal of the stent still was not possible because of the heavy encrustation at the upper end of the double J stent, the stiff wire was used as a scaffold, and a 9-F peel-away sheath (Peel-Away Introducer set; Cook, Inc, Bloomington, Indiana) was inserted over the wire/ stent complex to its hub without its inner dilator (Fig 1b). Resistance was often encountered, but with
3
gentle rotation, the peel-away sheath could be advanced over the encrusted stent. The peel-away sheath was split to allow the stent to be grasped directly and retracted. The encrusted stent was withdrawn through the sheath over the stiff wire. The peel-away sheath was withdrawn leaving the stiff wire. A catheter was advanced over the stiff wire, and contrast material was injected to confirm the position in the renal pelvis. A new ureteral stent was inserted via the conduit (28-cm, 8-F Flexima ureteric stent) over the stiff wire (5). Stent Placement in a Long Tortuous Ileal Conduit. In long and tortuous ileal conduits, advancing the initial guide wire and catheter complex to the ureteric orifices is difficult. When the guide wire and catheter have been advanced to the renal pelvis, an Amplatz Ultra Stiff guide wire can be inserted through the catheter. The catheter can be removed, and an 8-F/10-F dilator/ sheath set can be used (Boston Scientific), which is advanced along the wire (Fig 1c) to the renal pelvis. A second Amplatz Ultra Stiff guide wire can be inserted, and the combination of both Amplatz Ultra Stiff guide wires straightens the conduit (Fig 1d). The dilator/sheath set is removed, and a 28-cm, 8-F ureteric stent is inserted (Fig 1e). The distal end of the ureteric stent is left protruding from the conduit.
Statistical Analysis Statistical analysis was performed using SPSS version 16.0 (SPSS Inc, Chicago, Illinois). Two-sided t tests and χ2 tests were performed. The level of statistical significance was set at P r .05.
RESULTS In patients presenting for primary stents, 90% (nine patients) of the contrast loopograms demonstrated reflux into the distal ureters with injection of contrast material from the distal Foley catheter. The success of ureteric reflux was increased by navigating a hydrophilic guide wire and catheter to the proximal end of the ileal conduit and injecting contrast material (described earlier); this identified the distal ureters in a further two cases increasing the success of opacification of the distal ureters to 100% (10 patients) in the de novo group. Reflux into the distal ureter/stent complex was demonstrated in 100% of cases of ureteric stent exchange.
Technical and Clinical Success Technical and clinical success is outlined in Table 2. Both cases of failed primary stent insertion proceeded to nephrostomy and antegrade ureteric stent insertion, a three-stage procedure: (i) initial 8-F nephrostomy inserted; (ii) antegrade ureteric insertion 24 hours later; and (iii) nephrostogram, confirmation of stent patency, and removal of nephrostomy. These failures were in patients
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Figure 1. A 65-year-old man with a history of cystectomy and ileal conduit formation for bladder cancer presented 5 years postoperatively with urinary obstruction and renal impairment. He originally had a retrograde ureteric stent placed via the conduit and currently presents for regular challenging stent exchanges. (a) A snare was used to capture the distal end of the double J stent. The ileal conduit was delineated with diluted contrast material beforehand, producing a road map of the ileal conduit. (b) After recanalization of the ureteric stent with a stiff wire, a second, stiffer wire was exchanged, and this allowed the stent to be straightened. The 9-F peel-away sheath was inserted over the wire/stent complex to remove the encrustations (arrow). (c) A wire within the renal collecting system was placed via the ileal conduit. The ileal conduit was long (4 20 cm) and extended from the level of L5. It was impossible to advance the peel-away sheath along the wire because of the kink and long conduit (asterisk). (d) After insertion of a wide-bore sheath, a second stiff wire was inserted to provide stability. (e) A 28-cm ureteric stent could be advanced via the ileal conduit over one of the stiff wires with the other wire acting as a scaffold. The two stiff wires have straightened the ileal conduit (asterisk).
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Table 2 . Technical and Clinical Success
Technical success Clinical success
Table 3 . Difficulty in Stent Placement as Measured by Fluoroscopy Time
Primary Stent
Exchange Stent
Placement (n ¼ 20)
Placement (n ¼ 70)*
18/20 (90%)
70/70 (100%)
Screening Time (min)
Of those technically
70/70 (100%)
successful (n ¼ 18) (100%)
n
Placement of two exchange stents was performed acutely for increased urea, creatinine, and inflammatory markers.
with convoluted and long ileal conduits. In both cases, the three-stage antegrade approach to inserting the ureteric stent was successful, and both patients had a good technical and clinical outcome from the procedure. All cases of technical success were also clinically successful with a reduction in urea (mean reduction, 5 mmol/L; range, 0–11 mmol/L) and creatinine (mean reduction, 20 μmol/L; range, 5–200 μmol/L) to the patients’ baseline, and reduction in inflammatory markers (mean reduction in white blood cell count, 4 109; range, 0–15 109; mean reduction in C-reactive protein, 15 mg/L; range, 0–100 mg/L). There was a significant difference between the reductions in parameters in primary versus exchange stent insertion (P r .001).
Duration and Difficulty of Procedure There was a significant difference in the fluoroscopy time to perform a primary stent insertion (mean fluoroscopy time, 18 min) versus an exchange stent insertion (mean fluoroscopy time, 6 min) (P ¼ .003) (Table 3). Significant factors associated with fluoroscopy time 4 31 minutes and technical failures were encrusted stents visualized on prior CT (P ¼ .012), increased length of conduit (4 20 cm) measured on procedural fluoroscopy (P ¼ .023), and ileal conduit kink (o 90 degrees) measured on procedural fluoroscopy (P ¼ .032).
Complications There were no cases of procedural or 30-day mortality. There were three complications. Two of these were immediate complications. One was a major (type C per SIR guidelines (3)) complication in a patient with retrograde exchange of sepsis requiring fluid resuscitation, intravenous acetaminophen 1 g (B. Braun, Melsungen, Germany), and intravenous antibiotics (amoxicillin/ clavulanic acid 1.2 g). The patient was discharged home in o 48 hours with no subsequent sequelae. The second immediate complication was a minor complication (type A per SIR guidelines (3)) that consisted of a ureteric injury in a patient with primary stent insertion, which manifested as leakage of contrast material from the distal ureter during retrograde stent placement. This leakage did not inhibit retrograde stent placement, and on CT urography performed immediately after the procedure, there was no further evidence of leakage.
Fluoroscopy Primary Stent Placement (n ¼ 20)
Exchange Stent Placement (n ¼ 70)
0–15 16–30
2 (10%) 16 (80%)
45 (64%) 15 (21%)
4 31*
2 (10%)
10 (15%)
n
Significant factors associated with fluoroscopy time 4 30 minutes were encrusted stents visualized on prior computed tomography (P ¼ .012), increased length of ileal conduit (4 20 cm) measured on procedural fluoroscopy (P ¼ .023), and ileal conduit kink (o 901) measured on procedural fluoroscopy (P ¼ .032).
There was one delayed major complication (type C per SIR guidelines (3)) in a patient with retrograde exchange. The patient presented with features of sepsis and required readmission 36 hours after the procedure. This patient required fluid resuscitation, intravenous acetaminophen 1 g and intravenous antibiotic therapy (amoxicillin/clavulanic acid 1.2 g). The patient was discharged home after an overnight hospital stay (o 48 h) with no further treatment required. Statistically, the single factor associated with complications was having encrusted stents visualized on prior CT (P ¼ .022).
DISCUSSION Primary and exchange retrograde ureteric stent placement via the ileal conduit is a safe and effective technique for maintaining urinary drainage in patients presenting with anastomotic stricture. The single procedure can be performed under conscious sedation with antibiotic prophylaxis as an outpatient procedure, although cases of emergency retrograde ileal conduit drainage are recognized (6). Retrograde stent placement negates the need for percutaneous nephrostomy and antegrade stent insertion. It also precludes the need for more invasive techniques to relieve obstructed ileal conduits. Retrograde stent placement permits continued urine drainage via the ileal conduit and allows successful retrograde stent exchange in the future maintaining the high durability of transileal stents (7,8). The technical success of the procedure (90% for primary placements and 100% for exchanges) is similar to other studies, which report rates of technical success ranging from 14%–86% for single-stage procedures (2,9– 11) and from 92%–95% for multistage procedures (7,8). Refluxing contrast material into the distal ureters is an important factor in achieving technical success. After the contrast loopogram has been performed, navigating a catheter and guide wire to the proximal end of the conduit and injecting contrast material can improve visualization of the distal ureters. The increased pressure
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that can be produced from injecting contrast material from within the conduit in close proximity to the ureters likely contributes to opacification of the ureters and distal conduit. Repeated exchanges can be performed safely and have high technical success rates (100% in this series). The complication rate of 4% is also similar to the complication rate from other studies, including studies placing stents in a three-stage procedure (4.4%) (8). Factors statistically associated with increased fluoroscopy screening time and technical difficulty included encrusted stents visualized on prior CT (P ¼ .012), increased length of ileal conduit (4 20 cm) (P ¼ .023), and ileal conduit kink (o 90 degrees) (Fig 2). Performing regular stent exchange can limit technical difficulty by reducing the frequency and quantity of encrustation. Additionally, using the double wire technique can help reduce kinking in tortuous ileal conduits potentially reducing fluoroscopy time. All ileal conduits in our institution are formed with a Wallace-type ureteroileal anastomosis. In this surgical procedure, both distal ureters are anastomosed together and to the proximal end of the ileal conduit. It is possible (although not investigated in this study) that retrograde navigation of a Bricker-type anastomosis may be more challenging and have a less favorable outcome than we have demonstrated. A Bricker-type anastomosis involves each distal ureter being anastomosed end-to-side of the ileal conduit. Both types of anastomosis are refluxing anastomoses and are associated with different complications. The Wallace-type anastomosis is criticized because a ureteric stone or stricture can cause obstruction to both
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kidneys if present, and if a subsequent nephroureterectomy is required, the surgical procedure is more difficult. The Bricker-type anastomosis is criticized because it is more likely to become to result in stricture, and it requires increased operative time for creation of the anastomosis. The timing of stent exchange is important. The only factors statistically associated with complications were an encrusted stent, which can be avoided by regular retrograde stent exchange. In our practice, stents are routinely exchanged every 6 months; however, in some circumstances (eg, repeated infections, encrustations, lithiasis, blockages) we increase the frequency to every 3–4 months, following discussion in a multidisciplinary team setting. This frequency reduces the likelihood of patients presenting to the department with blocked stents and urosepsis. In the event of a patient presenting between planned stent exchanges with urosepsis, we would advocate percutaneous nephrostomy to decompress the system and antibiotic treatment with retrograde exchange of the ureteroileal stent via the ileal conduit at a later date (6). In the event of an obstructed stent without signs or symptoms of urosepsis, urgent retrograde stent exchange via the conduit would be the treatment of choice. This treatment reduces the risk from performing percutaneous nephrostomy and allows rapid restoration of renal function. Patients prefer retrograde exchange via the conduit because they can lie supine rather than prone, which is an important consideration for comfort in patients with ileal conduits. There was a difference in reductions of urea, creatinine, and inflammatory markers when comparing primary and retrograde exchanges. The primary stents were inserted after patients presented with an obstructed urinary system, whereas patients receiving exchange stents had previously had the urinary system decompressed. Also, the patients receiving primary stents had presented acutely and were more likely to have increased inflammatory markers and to be systemically unwell. This study has limitations. First, it was retrospective in nature. There are no comparison groups. Data collection was limited to procedural records and clinical follow-up, which was relatively short at 36 months. The number of patients included in the study was also small. In conclusion, retrograde placement of ureteric stents via the ileal conduit is safe and effective and should be considered for a first-time occurrence of a blocked ileal conduit. Regular stent exchange should be a priority because encrustations increase the risk of complications and procedural difficulty.
ACKNOWLEDGMENT Figure 2. A long (4 20 cm) ileal conduit and a kinked conduit with an initial angle of o 901 (indicated by black lines).
The authors thank Dr. Victoria Allgar (Hull and York Medical School) for her assistance with statistical analysis of the data.
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REFERENCES 1. Gilbert SM, Lai J, Saigal CS, et al. Downstream complications following urinary diversion. J Urol 2013; 190:916–922. 2. Zaleski GX, Funaki B, Newmark G. Placement of retrograde nephroureteral stents through ileal conduits. AJR Am J Roentgenol 1998; 170:1275–1278. 3. Sacks D, McClenny TE, Cardella JF, Lewis CA. Society of Interventional Radiology clinical practice guidelines. J Vasc Interv Radiol 2003; 14: S199–S202. 4. Venkatesan AM, Kundu S, Sacks D, et al. Practice guidelines for adult antibiotic prophylaxis during vascular and interventional radiology procedures. Written by the Standards of Practice Committee for the Society of Interventional Radiology and Endorsed by the Cardiovascular Interventional Radiological Society of Europe and Canadian Interventional Radiology Association [corrected]. J Vasc Interv Radiol 2010; 21: 1611–1630. 5. Tapping CR, Boardman P. Retrograde exchange of heavily encrusted ureteric stents via the ileal conduit: a technical report. J Med Imaging Radiat Oncol 2014; 58:75–78.
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6. Tapping CR, Boardman P. Post laparotomy retrograde navigation of an obstructed ileal conduit to relieve urinary sepsis. J Vasc Interv Radiol 2013; 24:1752–1754. 7. Tal R, Bachar GN, Baniel J, et al. External-internal nephro-uretero-ileal stents in patients with an ileal conduit: long-term results. Urology 2004; 63:438–441. 8. Alago W Jr, Sofocleous CT, Covey AM, et al. Placement of transileal conduit retrograde nephroureteral stents in patients with ureteral obstruction after cystectomy: technique and outcome. AJR Am J Roentgenol 2008; 191:1536–1539. 9. Drake MJ, Cowan NC. Fluoroscopy guided retrograde ureteral stent insertion in patients with a ureteroileal urinary conduit: method and results. J Urol 2002; 167:2049–2051. 10. Banner MP, Amendola MA, Pollack HM. Anastomosed ureters: fluoroscopically guided transconduit retrograde catheterization. Radiology 1989; 170:45–49. 11. Applbaum YN, Diamond AB, Rappoport AS. Retrograde ureteral catheterization via the ileal conduit. AJR Am J Roentgenol 1986; 146: 61–63.
Retrograde Transileal Conduit Stent Placement for Obstructed Uropathy—Success of Primary and Exchange Stent Placement Charles Ross Tapping, FRCR, James H. Briggs, FRCR, Mark W. Little, MBBS, Mark J. Bratby, FRCR, Jane Phillips-Hughes, FRCR, Jeremy P. Crew, FRCUrol, and Phil Boardman, FRCR
ABSTRACT Purpose: To assess the safety, success, and complications associated with retrograde ureteric stent insertion via the ileal conduit. Materials and Methods: The study population comprised 35 consecutive patients (17 men and 18 women; mean age, 55 y; age range, 40–75 y) requiring primary (20 stents) and exchange (70 stents) retrograde ureteric stent insertion via the ileal conduit over a 3-year period. Patient demographic data, procedural and technical data, and clinical follow-up data were collected. Results: Technical success was 90% (18 of 20) for primary stent placement and 100% (70 of 70) for stent exchange. There were two immediate complications (o 24 h) of sepsis and ureteric injury and one early complication (4 25 h but o 30 d) of sepsis requiring observation and medical management. Difficult procedures (defined as a fluoroscopy screening time 4 31 min) and technical failures were found to be associated with encrusted stents visualized on prior computed tomography (P ¼ .012), increased length of ileal conduit (4 20 cm) (P ¼ .023), and ileal conduit kink (o 90 degrees) (P ¼ .032). Only the occurrence of encrusted stents visualized on prior computed tomography (P ¼ .022) was associated with complications. Conclusions: Retrograde placement of ureteric stents via the ileal conduit is safe and effective. Retrograde stent placement should be considered the treatment option of choice for a first-time occurrence of obstructive uropathy at the ureteroileal anastomosis.
Ureteroileal anastomotic strictures are a well-known complication following ileal conduit formation after radical cystectomy, occurring in up to 16% of cases (1). Open surgical revision of the anastomosis is often technically challenging because of scar tissue surrounding the operative site. Interventional radiology techniques involving either retrograde or antegrade stent insertions are a robust alternative to open surgery. Antegrade stents enter the patient via the back and traverse the kidney and terminate preferably outside the ileal conduit. Retrograde stents enter the ileal conduit and terminate in the renal collecting system. Although placement of antegrade stents is technically easier, patients are
Department of Radiology (C.R.T., J.H.B., M.W.L., M.J.B., J.P.-H.), Oxford University Hospitals, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK; Departments of Radiology (C.R.T., J.P.-H., P.B.) and Urology (J. P.C.), Oxford University Hospitals, Churchill Hospital, Headington, Oxford, United Kingdom. Received August 12, 2013; final revision received February 10, 2014; accepted February 12, 2014. Address correspondence to C.R.T.; E-mail: [email protected] None of the authors have identified a conflict of interest. & SIR, 2014 J Vasc Interv Radiol 2014; XX:]]]–]]] http://dx.doi.org/10.1016/j.jvir.2014.02.013
usually more comfortable with retrograde placement via the conduit. The retrograde approach also offers advantages in terms of minimizing potential for complications from puncturing the kidney (bleeding) and infection (2). Long-term management of patients with stents placed across ureteroileal strictures requires regular stent exchange to prevent the stents from becoming encrusted and blocked, which would require emergency stent exchange or nephrostomy to prevent infection and urinary sepsis. Although this technique has been described previously, it can often be challenging to perform. No study has assessed predictive factors for success and aimed to improve success at retrograde stent placement via the ileal conduit. The purpose of this study was to assess the safety, success, and complications associated with retrograde ureteric stent insertion via the ileal conduit.
MATERIALS AND METHODS The review board at our institution classified this study as service evaluation and waived the need for formal approval and study consent. Over a 36-month period, 90 retrograde stents were inserted in 35 consecutive patients. All patients presenting to our unit for primary stent insertion or retrograde ureteric stent exchange via
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the ileal conduit were included. Primary stent insertion with subsequent exchanges during the study period was performed in 10 patients. These patients were included with a cohort of 25 patients who had previously had stents inserted either in our institution or within our region. Among the 25 patients who had previously had stents inserted, 4 patients had stents inserted surgically, 8 patients had stents inserted with a combination of antegrade and retrograde approaches with a two-stage or three-stage technique, and 13 patients had a de novo stent insertion in a retrograde manner as described in this article. In our institution, retrograde stents are not usually inserted endoscopically. The cohort comprised 17 men and 18 women with a mean age of 55 years (range, 40–75 y). Patient demographics are presented in Table 1. The initial indication for ileal conduit formation was malignancy in 70% of patients. The remaining 30% of patients were treated for benign disease, including neurogenic bladder dysfunction, bladder sphincter detrusor overactivity, and chronic inflammatory disease of the bladder.
Definitions and Endpoints Regarding ileal conduit anatomy, the distal end of the ileal conduit is the portion of the ileal conduit nearest the Table 1 . Patient Demographics Exchange Primary Stent Placement (n ¼ 10
(n ¼ 25 Patients)
P Value
56 (40–72)
63 (48–75)
.658
45:55 2.3
50:50 6.7
.852 .658
Mean length of
18
19
.023*
conduit (cm) ASA grade (I–VI)
I–II
I–II
.958
Diabetes (%)
35
45
.655
Hypertension (%) Ischemic heart
50 25
45 40
.099 .124
40
38
II
30
28
III IV
20 10
24 10
V
0
0
Male:female Mean age of conduit (y)
disease (%) Renal disease (%)† I
.991
ASA ¼ American Society of Anesthesiologists. Significant factor P o .05. † Renal disease classified according to creatinine clearance (CrCl) calculated by the Cockcroft-Gault formula using the National Kidney Foundation classification system: stage I, CrCl Z 90 mL/min/1.73 m2; stage II, CrCl 60–89 mL/min/1.73 m2; stage III, CrCl 30–59 mL/min/1.73 m2; stage IV, CrCl 15–29 mL/ min/1.73 m2; and stage V, CrCl r 15 mL/min/1.73 m2. n
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ostomy, and the proximal end is the portion nearest the ureteric anastomosis. Technical procedural success was defined as placing the retrograde ureteric stent via the ileal conduit with the proximal end of the stent in the renal collecting system and the distal end outside of or just inside the ileal conduit and it draining urine. If the ureteric stent was visible external to the patient, confirming urine drainage was simple and immediate. If the distal end of the stent remained within the conduit, confirmation of urine drainage was noted when urine was seen collecting within the drainage bag attached to the patient’s skin after the procedure. Clinical success was defined as continued drainage of urine via the stent until stent exchange (not requiring further interventional radiology or urologic surgery input) and associated reduction in urea, creatinine, and inflammatory markers after the procedure, if applicable. Complications were defined as per Society of Interventional Radiology (SIR) guidelines and were divided into major and minor complications (3). Fluoroscopy screening time was recorded. Procedures were divided according to fluoroscopy screening times of 0–15 minutes, 16–30 minutes, and 4 31 minutes. Numerous factors were studied in relation to complications and duration of fluoroscopy screening and included age of conduit, length of conduit (measured from procedural contrast loopogram), presence of stent-related calcification, kink (o 90 degrees), American Society of Anesthesiologists grade, diabetes mellitus, ischemic heart disease, hypertensive disease, and presence of renal disease.
Stent Placement
Patients) Age (y), mean (range)
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General Retrograde Ureteric Stent Insertion Technique Primary Stent Placement. Computed tomography (CT) was performed before the procedure in all patients presenting with obstructive uropathy or sepsis. Patients received prophylactic antibiotics before the proce dure: amoxicillin/clavulanic acid 1.2 g administered intravenously (MA Holder, Aprilia, Italy) (4). In cases of preexisting penicillin allergy, ceftriaxone 750 mg administered intravenously was used (Stravencon Ltd, London, UK). Conscious sedation was achieved with intravenous administration of 3 mg midazolam (Mercury Pharma International Ltd, Dublin, Ireland) and 50 μg fentanyl (Halmeln Pharmaceuticals Ltd, Gloucester, UK) before the procedure. A 12-F Foley catheter (C.R. Bard, Inc, Covington, Georgia) was introduced into the ileal conduit, and the 10-mL balloon was inflated. Contrast material was injected to provide a road map of the conduit. Contrast material was injected via the catheter to reflux up the ureters, which helped to guide access. If contrast material failed to identify the distal ureters, a hydrophilic guide wire (Terumo, Tokyo, Japan) was inserted into a 4-F Berenstein II catheter (Cordis, Miami Lakes, Florida) (alongside the inflated Foley catheter). The wire and catheter were manipulated to the
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blind end (proximal end) of the conduit, and contrast material was injected via the catheter from the proximal end of the conduit. The perianastomotic injection of contrast material helped to increase identification of the ureters. The wire and catheter were engaged into the distal ureter and navigated to its proximal end. When the catheter and guide wire reached the renal collecting system, the guide wire was removed, and contrast material was injected to confirm location. An Amplatz Ultra Stiff guide wire (William Cook Europe, Bjaeverskov, Denmark) was inserted, and the catheter was removed. A 28-cm, 8-F Flexima ureteral stent (Boston Scientific, Natick, Massachusetts) was inserted over the wire, and the distal end of the stent was positioned to protrude out of the conduit to allow for easier exchange in 4–6 months. Exchange Stent Insertion. Antibiotics and sedation were prescribed as noted for primary stent placement. The distal end of the ureteric stent was ideally protruding from the ileal conduit (see further on if this was not the case) and was firmly grasped. A stiff wire was inserted under fluoroscopy control. The existing stent was carefully withdrawn. A 4-F Berenstein II catheter was exchanged over the stiff wire, and contrast material was injected to confirm the position and location within the collecting system. A new 28-cm, 8-F Flexima ureteric stent was inserted over an Amplatz Ultra Stiff guide wire after removal of the Berenstein II catheter, and the distal end of the stent was left protruding from the ileal conduit.
Modifications to Basic Technique if Heavily Calcified or Long Tortuous Ileal Conduit Heavily Calcified Stent Exchange. Occasionally, the distal end of the 28-cm, 8-F Flexima ureteral stent was found to have migrated inward and was not accessible from the ileal conduit. In these cases, the stent was snared with a 10-mm Amplatz GooseNeck Snare (ev3, Plymouth, Minnesota) (Fig 1a). Under fluoroscopy guidance, the distal end of the ureteral stent was withdrawn out of the conduit and grasped with a forceps. If the stent was heavily encrusted, the stiff end of a stiff hydrophilic wire (Terumo) was carefully inserted into the stent and advanced under fluoroscopy guidance. This wire was normally advanced through the blocked stent up to the proximal J tip. The hydrophilic wire was exchanged for a stiff wire (Amplatz Ultra Stiff guide wire), and an attempt was made to withdraw the stent. If withdrawal of the stent still was not possible because of the heavy encrustation at the upper end of the double J stent, the stiff wire was used as a scaffold, and a 9-F peel-away sheath (Peel-Away Introducer set; Cook, Inc, Bloomington, Indiana) was inserted over the wire/ stent complex to its hub without its inner dilator (Fig 1b). Resistance was often encountered, but with
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gentle rotation, the peel-away sheath could be advanced over the encrusted stent. The peel-away sheath was split to allow the stent to be grasped directly and retracted. The encrusted stent was withdrawn through the sheath over the stiff wire. The peel-away sheath was withdrawn leaving the stiff wire. A catheter was advanced over the stiff wire, and contrast material was injected to confirm the position in the renal pelvis. A new ureteral stent was inserted via the conduit (28-cm, 8-F Flexima ureteric stent) over the stiff wire (5). Stent Placement in a Long Tortuous Ileal Conduit. In long and tortuous ileal conduits, advancing the initial guide wire and catheter complex to the ureteric orifices is difficult. When the guide wire and catheter have been advanced to the renal pelvis, an Amplatz Ultra Stiff guide wire can be inserted through the catheter. The catheter can be removed, and an 8-F/10-F dilator/ sheath set can be used (Boston Scientific), which is advanced along the wire (Fig 1c) to the renal pelvis. A second Amplatz Ultra Stiff guide wire can be inserted, and the combination of both Amplatz Ultra Stiff guide wires straightens the conduit (Fig 1d). The dilator/sheath set is removed, and a 28-cm, 8-F ureteric stent is inserted (Fig 1e). The distal end of the ureteric stent is left protruding from the conduit.
Statistical Analysis Statistical analysis was performed using SPSS version 16.0 (SPSS Inc, Chicago, Illinois). Two-sided t tests and χ2 tests were performed. The level of statistical significance was set at P r .05.
RESULTS In patients presenting for primary stents, 90% (nine patients) of the contrast loopograms demonstrated reflux into the distal ureters with injection of contrast material from the distal Foley catheter. The success of ureteric reflux was increased by navigating a hydrophilic guide wire and catheter to the proximal end of the ileal conduit and injecting contrast material (described earlier); this identified the distal ureters in a further two cases increasing the success of opacification of the distal ureters to 100% (10 patients) in the de novo group. Reflux into the distal ureter/stent complex was demonstrated in 100% of cases of ureteric stent exchange.
Technical and Clinical Success Technical and clinical success is outlined in Table 2. Both cases of failed primary stent insertion proceeded to nephrostomy and antegrade ureteric stent insertion, a three-stage procedure: (i) initial 8-F nephrostomy inserted; (ii) antegrade ureteric insertion 24 hours later; and (iii) nephrostogram, confirmation of stent patency, and removal of nephrostomy. These failures were in patients
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Figure 1. A 65-year-old man with a history of cystectomy and ileal conduit formation for bladder cancer presented 5 years postoperatively with urinary obstruction and renal impairment. He originally had a retrograde ureteric stent placed via the conduit and currently presents for regular challenging stent exchanges. (a) A snare was used to capture the distal end of the double J stent. The ileal conduit was delineated with diluted contrast material beforehand, producing a road map of the ileal conduit. (b) After recanalization of the ureteric stent with a stiff wire, a second, stiffer wire was exchanged, and this allowed the stent to be straightened. The 9-F peel-away sheath was inserted over the wire/stent complex to remove the encrustations (arrow). (c) A wire within the renal collecting system was placed via the ileal conduit. The ileal conduit was long (4 20 cm) and extended from the level of L5. It was impossible to advance the peel-away sheath along the wire because of the kink and long conduit (asterisk). (d) After insertion of a wide-bore sheath, a second stiff wire was inserted to provide stability. (e) A 28-cm ureteric stent could be advanced via the ileal conduit over one of the stiff wires with the other wire acting as a scaffold. The two stiff wires have straightened the ileal conduit (asterisk).
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Table 2 . Technical and Clinical Success
Technical success Clinical success
Table 3 . Difficulty in Stent Placement as Measured by Fluoroscopy Time
Primary Stent
Exchange Stent
Placement (n ¼ 20)
Placement (n ¼ 70)*
18/20 (90%)
70/70 (100%)
Screening Time (min)
Of those technically
70/70 (100%)
successful (n ¼ 18) (100%)
n
Placement of two exchange stents was performed acutely for increased urea, creatinine, and inflammatory markers.
with convoluted and long ileal conduits. In both cases, the three-stage antegrade approach to inserting the ureteric stent was successful, and both patients had a good technical and clinical outcome from the procedure. All cases of technical success were also clinically successful with a reduction in urea (mean reduction, 5 mmol/L; range, 0–11 mmol/L) and creatinine (mean reduction, 20 μmol/L; range, 5–200 μmol/L) to the patients’ baseline, and reduction in inflammatory markers (mean reduction in white blood cell count, 4 109; range, 0–15 109; mean reduction in C-reactive protein, 15 mg/L; range, 0–100 mg/L). There was a significant difference between the reductions in parameters in primary versus exchange stent insertion (P r .001).
Duration and Difficulty of Procedure There was a significant difference in the fluoroscopy time to perform a primary stent insertion (mean fluoroscopy time, 18 min) versus an exchange stent insertion (mean fluoroscopy time, 6 min) (P ¼ .003) (Table 3). Significant factors associated with fluoroscopy time 4 31 minutes and technical failures were encrusted stents visualized on prior CT (P ¼ .012), increased length of conduit (4 20 cm) measured on procedural fluoroscopy (P ¼ .023), and ileal conduit kink (o 90 degrees) measured on procedural fluoroscopy (P ¼ .032).
Complications There were no cases of procedural or 30-day mortality. There were three complications. Two of these were immediate complications. One was a major (type C per SIR guidelines (3)) complication in a patient with retrograde exchange of sepsis requiring fluid resuscitation, intravenous acetaminophen 1 g (B. Braun, Melsungen, Germany), and intravenous antibiotics (amoxicillin/ clavulanic acid 1.2 g). The patient was discharged home in o 48 hours with no subsequent sequelae. The second immediate complication was a minor complication (type A per SIR guidelines (3)) that consisted of a ureteric injury in a patient with primary stent insertion, which manifested as leakage of contrast material from the distal ureter during retrograde stent placement. This leakage did not inhibit retrograde stent placement, and on CT urography performed immediately after the procedure, there was no further evidence of leakage.
Fluoroscopy Primary Stent Placement (n ¼ 20)
Exchange Stent Placement (n ¼ 70)
0–15 16–30
2 (10%) 16 (80%)
45 (64%) 15 (21%)
4 31*
2 (10%)
10 (15%)
n
Significant factors associated with fluoroscopy time 4 30 minutes were encrusted stents visualized on prior computed tomography (P ¼ .012), increased length of ileal conduit (4 20 cm) measured on procedural fluoroscopy (P ¼ .023), and ileal conduit kink (o 901) measured on procedural fluoroscopy (P ¼ .032).
There was one delayed major complication (type C per SIR guidelines (3)) in a patient with retrograde exchange. The patient presented with features of sepsis and required readmission 36 hours after the procedure. This patient required fluid resuscitation, intravenous acetaminophen 1 g and intravenous antibiotic therapy (amoxicillin/clavulanic acid 1.2 g). The patient was discharged home after an overnight hospital stay (o 48 h) with no further treatment required. Statistically, the single factor associated with complications was having encrusted stents visualized on prior CT (P ¼ .022).
DISCUSSION Primary and exchange retrograde ureteric stent placement via the ileal conduit is a safe and effective technique for maintaining urinary drainage in patients presenting with anastomotic stricture. The single procedure can be performed under conscious sedation with antibiotic prophylaxis as an outpatient procedure, although cases of emergency retrograde ileal conduit drainage are recognized (6). Retrograde stent placement negates the need for percutaneous nephrostomy and antegrade stent insertion. It also precludes the need for more invasive techniques to relieve obstructed ileal conduits. Retrograde stent placement permits continued urine drainage via the ileal conduit and allows successful retrograde stent exchange in the future maintaining the high durability of transileal stents (7,8). The technical success of the procedure (90% for primary placements and 100% for exchanges) is similar to other studies, which report rates of technical success ranging from 14%–86% for single-stage procedures (2,9– 11) and from 92%–95% for multistage procedures (7,8). Refluxing contrast material into the distal ureters is an important factor in achieving technical success. After the contrast loopogram has been performed, navigating a catheter and guide wire to the proximal end of the conduit and injecting contrast material can improve visualization of the distal ureters. The increased pressure
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that can be produced from injecting contrast material from within the conduit in close proximity to the ureters likely contributes to opacification of the ureters and distal conduit. Repeated exchanges can be performed safely and have high technical success rates (100% in this series). The complication rate of 4% is also similar to the complication rate from other studies, including studies placing stents in a three-stage procedure (4.4%) (8). Factors statistically associated with increased fluoroscopy screening time and technical difficulty included encrusted stents visualized on prior CT (P ¼ .012), increased length of ileal conduit (4 20 cm) (P ¼ .023), and ileal conduit kink (o 90 degrees) (Fig 2). Performing regular stent exchange can limit technical difficulty by reducing the frequency and quantity of encrustation. Additionally, using the double wire technique can help reduce kinking in tortuous ileal conduits potentially reducing fluoroscopy time. All ileal conduits in our institution are formed with a Wallace-type ureteroileal anastomosis. In this surgical procedure, both distal ureters are anastomosed together and to the proximal end of the ileal conduit. It is possible (although not investigated in this study) that retrograde navigation of a Bricker-type anastomosis may be more challenging and have a less favorable outcome than we have demonstrated. A Bricker-type anastomosis involves each distal ureter being anastomosed end-to-side of the ileal conduit. Both types of anastomosis are refluxing anastomoses and are associated with different complications. The Wallace-type anastomosis is criticized because a ureteric stone or stricture can cause obstruction to both
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kidneys if present, and if a subsequent nephroureterectomy is required, the surgical procedure is more difficult. The Bricker-type anastomosis is criticized because it is more likely to become to result in stricture, and it requires increased operative time for creation of the anastomosis. The timing of stent exchange is important. The only factors statistically associated with complications were an encrusted stent, which can be avoided by regular retrograde stent exchange. In our practice, stents are routinely exchanged every 6 months; however, in some circumstances (eg, repeated infections, encrustations, lithiasis, blockages) we increase the frequency to every 3–4 months, following discussion in a multidisciplinary team setting. This frequency reduces the likelihood of patients presenting to the department with blocked stents and urosepsis. In the event of a patient presenting between planned stent exchanges with urosepsis, we would advocate percutaneous nephrostomy to decompress the system and antibiotic treatment with retrograde exchange of the ureteroileal stent via the ileal conduit at a later date (6). In the event of an obstructed stent without signs or symptoms of urosepsis, urgent retrograde stent exchange via the conduit would be the treatment of choice. This treatment reduces the risk from performing percutaneous nephrostomy and allows rapid restoration of renal function. Patients prefer retrograde exchange via the conduit because they can lie supine rather than prone, which is an important consideration for comfort in patients with ileal conduits. There was a difference in reductions of urea, creatinine, and inflammatory markers when comparing primary and retrograde exchanges. The primary stents were inserted after patients presented with an obstructed urinary system, whereas patients receiving exchange stents had previously had the urinary system decompressed. Also, the patients receiving primary stents had presented acutely and were more likely to have increased inflammatory markers and to be systemically unwell. This study has limitations. First, it was retrospective in nature. There are no comparison groups. Data collection was limited to procedural records and clinical follow-up, which was relatively short at 36 months. The number of patients included in the study was also small. In conclusion, retrograde placement of ureteric stents via the ileal conduit is safe and effective and should be considered for a first-time occurrence of a blocked ileal conduit. Regular stent exchange should be a priority because encrustations increase the risk of complications and procedural difficulty.
ACKNOWLEDGMENT Figure 2. A long (4 20 cm) ileal conduit and a kinked conduit with an initial angle of o 901 (indicated by black lines).
The authors thank Dr. Victoria Allgar (Hull and York Medical School) for her assistance with statistical analysis of the data.
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REFERENCES 1. Gilbert SM, Lai J, Saigal CS, et al. Downstream complications following urinary diversion. J Urol 2013; 190:916–922. 2. Zaleski GX, Funaki B, Newmark G. Placement of retrograde nephroureteral stents through ileal conduits. AJR Am J Roentgenol 1998; 170:1275–1278. 3. Sacks D, McClenny TE, Cardella JF, Lewis CA. Society of Interventional Radiology clinical practice guidelines. J Vasc Interv Radiol 2003; 14: S199–S202. 4. Venkatesan AM, Kundu S, Sacks D, et al. Practice guidelines for adult antibiotic prophylaxis during vascular and interventional radiology procedures. Written by the Standards of Practice Committee for the Society of Interventional Radiology and Endorsed by the Cardiovascular Interventional Radiological Society of Europe and Canadian Interventional Radiology Association [corrected]. J Vasc Interv Radiol 2010; 21: 1611–1630. 5. Tapping CR, Boardman P. Retrograde exchange of heavily encrusted ureteric stents via the ileal conduit: a technical report. J Med Imaging Radiat Oncol 2014; 58:75–78.
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6. Tapping CR, Boardman P. Post laparotomy retrograde navigation of an obstructed ileal conduit to relieve urinary sepsis. J Vasc Interv Radiol 2013; 24:1752–1754. 7. Tal R, Bachar GN, Baniel J, et al. External-internal nephro-uretero-ileal stents in patients with an ileal conduit: long-term results. Urology 2004; 63:438–441. 8. Alago W Jr, Sofocleous CT, Covey AM, et al. Placement of transileal conduit retrograde nephroureteral stents in patients with ureteral obstruction after cystectomy: technique and outcome. AJR Am J Roentgenol 2008; 191:1536–1539. 9. Drake MJ, Cowan NC. Fluoroscopy guided retrograde ureteral stent insertion in patients with a ureteroileal urinary conduit: method and results. J Urol 2002; 167:2049–2051. 10. Banner MP, Amendola MA, Pollack HM. Anastomosed ureters: fluoroscopically guided transconduit retrograde catheterization. Radiology 1989; 170:45–49. 11. Applbaum YN, Diamond AB, Rappoport AS. Retrograde ureteral catheterization via the ileal conduit. AJR Am J Roentgenol 1986; 146: 61–63.
