Original Article

Fluoroscopically guided transurethral removal and/or replacement of ureteric stents in women

Acta Radiologica 2015, Vol. 56(5) 635–640 ! The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185114533246 acr.sagepub.com

Eoghan McCarthy, John Kavanagh, Sean McKernan, Niamh O’Mahony, Niall McEniff, J Mark Ryan and Michael Guiney

Abstract Background: Traditionally double J ureteric stents have been removed and replaced via cystoscopy. Fluoroscopically guided procedures for the removal/replacement of stents using endovascular snare devices have previously been described as a successful alternative. Purpose: To evaluate the technical and clinical success of fluoroscopically guided transurethral removal and/or replacement of ureteric stents in women. To assess radiation dose and screening time associated with this approach. Material and Methods: A 31-month retrospective review of all ureteric stent removals and/or replacements under fluoroscopic guidance performed in a university hospital radiology department. Results: One hundred and fourteen procedures were performed in 83 patients. Thirty ureteric stents were removed and 84 ureteric stents were replaced. The majority of patients required stents for urinary tract obstruction secondary to malignancy (78.3%). Overall technical and clinical success rates (defined respectively as satisfactory removal/replacement and drainage of the collecting system) of 98.2% were attained. Mean screening time was 13.9 min (range, 1.0–67.6 min). Effective radiation dose was in the range of 0.69–132 mSv with a mean of 11.18 mSv equating to the dose of a contrastenhanced computed tomography abdomen/pelvis. Conclusion: Transurethral ureteric stent removal and replacement under fluoroscopic guidance is highly successful, well tolerated by patients with acceptable radiation exposure, and can obviate the need for cystoscopic retrieval.

Keywords Antegrade ureteric stent, fluoroscopy, endovascular snare device Date received: 12 January 2014; accepted: 4 April 2014

Introduction Ureteric stent placement is an established procedure to relieve an obstructed renal collecting system (1,2). These stents may be placed in a retrograde or antegrade fashion (3). While stent placement for calculi is usually a short-term bridge to definitive therapy, benign or malignant ureteric strictures may require long-term stents. Unfortunately metallic stents have poor patency rates and have not been successful in the management of these strictures (4). Consequently, plastic stents remain the mainstay for long-term treatment. These stents are prone to obstruction and encrustation from precipitation of urinary salts. When these stents block

patients are at increased risk of obstructive uropathy and pyonephrosis. It is recommended that indwelling ureteric stents be replaced at 4–6-monthly intervals, or sooner if they are blocked (5). Traditionally this replacement has been performed cystoscopically. This can be performed at flexible cystoscopy, but often requires rigid cystoscopy, necessitating a general Department of Interventional Radiology, St James’s Hospital and Trinity College, Dublin, Ireland Corresponding author: John Kavanagh, Department of Interventional Radiology, St James’s Hospital and Trinity College, Dublin 8, Ireland. Email: [email protected]

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anesthetic. Successful retrograde fluoroscopic guided removal/replacement of double J stents in the interventional suite has been described in the literature (5–7). The perceived drawbacks of this approach are the time taken to perform and the radiation dose associated with the procedure. The main benefit of such an approach is the avoidance of general anesthetic. In this study we present our experience of this procedure. We review our technical and clinical success and how this compares with existing literature. We evaluate time expenditure of the procedure and evaluate for the first time radiation dose associated with such procedures.

UT, USA). This catheter was then guided into the bladder over the indwelling wire. The wire was subsequently removed and the snare introduced through the catheter into the bladder. The distal J of the ureteric stent was snared (Fig. 1) and the stent was withdrawn to the urethral orifice. If the stent was for replacement, the indwelling stent, now at the urethral orifice was cannulated with a hydrophilic 0.35-inch wire (Terumo Europe, Leuven, Belgium), which was introduced through the stent to the renal pelvis (Fig. 2).

Material and Methods Patients We carried out a retrospective review to identify all transurethral ureteric stent removals and replacements on female patients performed by interventional radiology over a 31-month period (June 2010–February 2013). Patients were identified via the interventional room logbooks and via a Picture Archive and Communications System (PACS) audit using the search term ‘‘ureteric stent’’. Patient demographics and relevant clinical data were obtained from the Electronic Patient Record (EPR) and their written medical records. The study had institutional review board approval and consent was not required. One hundred and fourteen procedures were performed on 83 consecutive women. The mean age of the cohort was 53 years (range, 21–81 years). The majority of patients required stents for urinary tract obstruction secondary to malignancy (78.3%), with the reminder requiring stents secondary to benign conditions such as endometriosis, fibroids, or inflammatory/infectious ureteral strictures.

Fig. 1. A 44-year-old woman with cervical carcinoma. The distal J of the ureteric stent is snared using the gooseneck snare and retracted through the urethral meatus.

Procedure The procedure was carried out under conscious sedation with IV antibiotic coverage (Co-amoxiclav, 1.2 g). The patient arrived in the interventional suite with an indwelling urinary catheter in situ, this catheter had either been placed by house staff or for oncology day-case patients by nursing staff on the oncology day ward. The procedure was performed in the supine position. The urogenital region was sterilized with bethadine or chlorhexidine based antiseptic. The bladder was filled with dilute intravenous contrast material. A 0.35inch guidewire was manipulated into the bladder via the urinary catheter, which was then removed. Topical lidocaine gel was applied to the endovascular snare catheter (Gooseneck snare, ev3, Plymouth, MN, USA or OneSnare, Merit Medical, South Jordan,

Fig. 2. The 0.35-inch hydrophilic wire is then advanced through the distal J into the right renal pelvis.

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The ureteric stent was removed and a 5Fr Bernstein catheter advanced over the hydrophilic wire into the renal pelvis (Fig. 3), a stiff 0.35-inch wire was left in the renal pelvis and an 8Fr ureteric stent (Flexima Ureteral Stent, Boston Scientific, Natick, MA,USA) advanced into the collecting system (Fig. 4). The pigtails were deployed in the standard fashion and the indwelling wires removed. Choice of stent length ranged through 22 cm, 24 cm, and 26 cm depending on the patient’s body habitus. Primary operators for

all cases were NME, JMR, or MG, each with over 10 years of experience as an attending interventional radiologist. With evolution of technique, there was minimal variation from the above technique. Occasionally operators injected the Bernstein catheter with contrast to outline the collecting system. A newer wire, the Radiofocus glidewire ‘‘Advantage’’ (Terumo Europe, Leuven, Belgium), which combines the flexibility of the hydrophilic wire and stiffness of the braided wire was also adopted by two operators negating wire exchange and Bernstein catheter placement. This wire was typically advanced directly through the existing ureteric stent at the urethral orifice allowing for withdrawal and immediate stent replacement, thus cutting down on screening time, radiation dose, and procedure length.

Patient outcomes

Fig. 3. A Bernstein catheter is advanced into the right renal pelvis and the 0.35-inch hydrophilic wire is exchanged for a stiff 0.35-inch wire.

The primary outcome was technical and clinical success of treatment. Technical success was regarded as successful removal and/or replacement of the ureteric stent in the interventional suite. Clinical success was defined as satisfactory drainage of the collecting system, that is to say no deviation from base-line renal function necessitating stent change within 30 days of the procedure. Secondary outcomes including radiation dose and screening time were also recorded. Effective dose was calculated based on the final dose area product (DAP) for each procedure and using 0.26 mSv/Gycm2 as the conversion factor (8). Screening time was obtained from the EPR.

Results

Fig. 4. A new 8Fr double J stent is advanced into the right collecting system.

Of the 114 procedures performed, 30 ureteric stents were removed and 84 ureteric stents were replaced within the study period. The overall technical success rate of the procedure was 98.2% (112 procedures). One procedure failed as the distal J of the stent had withdrawn completely into the ureter, rendering transurethral snaring impossible. In the remaining case the distal J of the stent resided within a bladder diverticulum and could not be snared. In both instances the patients went on to have successful cystoscopic management. All technically successful procedures were also clinically successful with satisfactory drainage of the renal system. Definitive time of procedure was not accurately maintained in all cases, as such procedure screening time was used as a surrogate marker. The mean screening time was 13.9 min (range, 1.0–67.7 min). The mean radiation exposure for the procedure was 4304.7 mGy.m2 (range, 266.6–51086.3 mGy.m2) equating to a mean effective dose of 11.18 mSv (range, 0.73–132 mSv).

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There were no major complications after the procedure. No urinary tract infections or prolonged episodes of hematuria (>24 h) were identified.

Discussion Traditionally, retrograde stenting of the ureter has been carried out via cystoscopic guidance, the benefit of this approach being direct visualization. This can be performed with either a flexible or rigid cystoscope. Rigid cystoscopic procedures tend to be painful and can be poorly tolerated without general anesthetic. The technique of antegrade removal of double J stent has also been described. This approach requires a large percutaneous tract and potentially traumatizes the renal parenchyma. As such this should be reserved for failed retrograde attempts (9). Transvesical ureteric stent removal and replacement under fluoroscopic guidance was first described by Yedlicka et al. (6). It is highly successful and in general well tolerated by patients. Pain is controlled with a combination of topical lidocaine gel to the urinary tract and IV conscious sedation (midazolam and fentanyl) as required. The procedure, if clinically appropriate can be performed as a day case. Park et al. described four modified fluoroscopically guided technique for the removal of stents via the bladder: (i) the ‘‘Guide-Wire Lasso’’ technique, involves introducing a folded 0.032-inch guidewire, through a 7F arterial

sheath, encircling the bladder end of the stent, fixing this to the arterial sheath and removing both from the bladder; (ii) the ‘‘Simple Snare’’ technique, which is the approach employed in our institution and described above; (iii) the ‘‘Direct Grasping’’ technique, this involves introducing grasping forceps or myocardial biopsy forceps into the bladder and directly grasping the stent tip for removal; and (iv) the ‘Modified Snare’ technique, whereby a snare and a 0.032-inch hydrophilic guidewire are inserted into the bladder lying on either side of the distal J. The wire is grasped by the snare forming a lasso, which is tightened around the distal stent and then the wire and snare are removed (10). Our technical success rate at 98.2% is in line with existing literature (range, 95.4–100%) (5,6,10–12). As discussed, all retrieval attempts in our institution were carried out using the ‘‘Simple Snare’’ technique. The use of endovascular/myocardial biopsy forceps may have been successful in the retrieval of the stent encountered where the distal J resided in a bladder diverticulum. It is unlikely that any fluoroscopically guided approach could have retrieved the stent that had fully retracted into the ureter. There is a learning curve associated with this procedure as evident from Figs 5 and 6 where higher radiation exposures and longer screening times were seen early in the study. Two important steps of the procedure we would like to highlight are: (i) maintenance of the intra-vesical wire in preparation for snaring the distal J.

Fig. 5. A dot-plot graph of radiation dose (mSv) on the Y axis and duration of the study (June 2010–February 2013) on X axis of all ureteric stent changes performed. The black line illustrates the trend of reducing radiation dose over the study period.

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Fig. 6. A dot-plot graph of time (min) and duration of the study (June 2010–February 2013) on the X axis of all stent changes performed. The black line illustrates the trend of reducing screening time during the study period.

On two occasions bladder access was compromised as the primary operator lost wire access. As a result the patients required re-catheterization for a second successful attempt; (ii) Deployment of the stent. The distal J must be deployed in the bladder. If too much pushing occurs the distal end may be lost into the ureter (5–7). Not enough pressure and the J may form in the urethra requiring extra manipulation and pushing from below resulting in un-necessary discomfort. Indeed the distal J of the stent in the patient exposed to the highest effective dose (132 mSv) migrated into the distal ureter on deployment. A complex retrieval with angiographic balloons and glide catheters followed prior to successful replacement. (Fig. 7) This illustrates a further learning point, currently if a stent is seen to be in the distal ureter on initial screening the procedure is abandoned and referred for cystoscopic replacement. This is the first study to properly assess the effective radiation dose associated with the fluoroscopic approach. While doses were larger during the initial stages, the mean effective dose at 11.18 mSv is equivalent to the dose of a contrast-enhanced computed tomography of the abdomen and pelvis (13). According to the linear no threshold model of radiation exposure and cancer risk, this mean dose equates to an estimated additional cancer risk of 0.068% based on a woman aged 53 years (14). In a population which is largely

Fig. 7. A 72-year-old woman with transitional cell carcinoma of the bladder. During routine ureteric stent replacement the distal J of the right ureteric stent was inadvertently deployed in the distal ureter. The stent was retrieved and snared using multiple guidewires and angiographic balloons.

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made up of patients with malignancy this can be viewed as an acceptable risk. Furthermore, cystoscopic placement is not devoid of radiation exposure as fluoroscopy is often necessary to prove correct stent positioning during and after the procedure (9). Kawahara et al. have described a new technique for retrieval of ureteric stents. In this cohort a crochet hook was used to grasp the stent without cystoscopic or fluoroscopic guidance (15). It is, however, unlikely that stent placement will ever be routinely performed without image guidance. Costings for individual cases have not been performed due to differences in snare and wire choice between operators. A significant benefit of fluoroscopically guided removal and replacement is that it negates the need for the general anesthetic costs associated with rigid cystoscopy. This is borne out in the literature with a saving of nearly $100 per procedure in the costings carried out by Chang et al. (5). This study is limited by its retrospective nature and the lack of clear documentation of procedural time. While successful retrograde replacement of a ureteric stent in male patients has been described, we have limited our study to female patients (12). Indeed, during the study period one case of retrograde replacement was attempted on a man. The length of the patient’s urethra did not allow for the ureteric stent to be withdrawn to the meatus while retaining its position in the distal ureter. This patient was referred for successful cystoscopic replacement. In conclusion, fluoroscopically guided transurethral removal and/or replacement of ureteric stents in women is a feasible and safe alternative to cystoscopy. Radiation doses are acceptable, and although a learning curve is identified initially, with time operators become more adept at the procedure. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

2. Hepperlen TW, Mardis HK, Kammandel H. Selfretained internal ureteral stents: a new approach. J Urol 1978;119:731–734. 3. Mitty HA, Train JS, Dan SJ. Placement of ureteral stents by antegrade and retrograde techniques. Radiol Clin North Am 1986;24:587–600. 4. Hekimoglu B, Men S, Pinar A, et al. Urothelial hyperplasia complicating use of metal stents in malignant ureteral obstruction. Eur Radiol 1996;6:675–681. 5. Chang RS, Liang HL, Huang JS, et al. Fluoroscopic guidance of retrograde exchange of ureteral stents in women. Am J Roentgenol 2008;190:1665–1670. 6. Yedlicka JW Jr, Azipuru R, Hunter DW, et al. Retrograde replacement of internal double-J ureteral stents. Am J Roentgenol 1991;156:1007–1009. 7. De Baere T, Denys A, Pappas P, et al. Ureteral stents: exchange under fluoroscopic control as an effective alternative to cystoscopy. Radiology 1994;190:887–889. 8. Hart D, Wall BF. Radiation exposure of the UK population from medical and dental x-ray examinations, NRPB-W4. See http://www.hpa.org.uk/webc/HPA webfile/HPAweb_C/1194947396204 (2002), accessed 08 January 2014. 9. Katske FA, Celis P. Technique for removal of migrated double-J ureteral stent. Urology 1991;37:579. 10. Park SW, Cha IH, Hong SJ, et al. Fluoroscopicallyguided transurethral removal and exchange of ureteral stents in female patients: technical notes. J Vasc Interv Radiol 2007;18:251–256. 11. Carrafiello G, Lagana D, Manigini M, et al. Fluoroscopically guided retrograde replacement of ureteral stents. Radiol Med (Torino) 2007;112:821–825. 12. Ozkan O, Akinci D, Bozlar U, et al. Rettrograde ureteral stent exchange under fluoroscopic guidance. Diagn Interv Radiol Ank Turk 2009;15:51–56. 13. ICRP, 2000. Managing Patient Dose in Computed Tomography. ICRP Publication 87. Ann ICRP 2000;30(4). 14. National Research Council. Health risks from exposure to low levels of ionizing radiation. BEIR VII Phase 2. Washington, DC: National Academies Press, 2006. 15. Kawahara T, Ito T, Terao H, et al. Ureteral stent exchange under fluoroscopic guidance using the crochet hook technique in women. Urol Int 2012;88:322–325.

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or replacement of ureteric stents in women.

Traditionally double J ureteric stents have been removed and replaced via cystoscopy. Fluoroscopically guided procedures for the removal/replacement o...
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