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Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not?

Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To... Arab Journal of Urology (2013) 11,85–90 Arab Journal of Urology (Official Journal of the Arab Association of Urology) www.sciencedirect.com STONES/ENDOUROLOGY ORIGINAL ARTICLE Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not? Mohamed M. Abdallah , Mohamed Selim, Tarek Abdelbakey Urology Department, Menoufiya University Hospital, Menoufiya, Egypt Received 18 November 2012, Received in revised form 17 December 2012, Accepted 18 December 2012 Available online 24 January 2013 KEYWORDS Abstract Objectives: To assess the role of temporary thermally expandable urethral stents in maintaining urethral patency in patients with a recurrent bulbar Bulbar urethral stric- urethral stricture. ture; Patients and methods: Twenty-three men with a recurrent bulbar urethral Stents; stricture after several attempts at direct visual internal urethrotomy (DVIU) and/ Recurrent stricture or failed urethroplasty were managed with a thermally expandable, biocom- patible nickel–titanium alloy urethral stent (Memokath MK044, Pnn Medical, ABBREVIATIONS Kvistgaard, Denmark). The stents were applied by a special mounting device via a DSD, detrusor sphinc- rigid urethroscope after DVIU. All patients were followed using plain radiography, ter dyssynergia; DVIU, uroflowmetry and urine analysis every 3 months for 1 year, and then every 6 months. direct visual internal Results: The mean (SD) age of the patients was 55.4 (7.3) years and the mean urethrotomy; PVR, (SD) stricture length was 3.6 (1.2) cm. All patients tolerated the stent, with minimal postvoid residual discomfort in some patients. Four patients (17%) had urinary tract infections, three (urine) (13%) had haematuria, three (13%) had obstructed stents due to encrustation, in five (22%) the stent migrated, and two patients had no delayed complications. The mean (SD) follow-up was 17.4 (6.1) months. Corresponding author. Address: Department of Urology, Faculty of Medicine, Shibin Elkom, Minofia, Egypt. Tel.: +20 1003413438. E-mail address: mmarzouk@yahoo.com (M.M. Abdallah). Peer review under responsibility of Arab Association of Urology. Production and hosting by Elsevier 2090-598X ª 2013 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.aju.2012.12.005 86 Abdallah et al. Conclusion: Urethral stenting with nickel–titanium alloy thermally expandable stents can be an acceptable temporary procedure for patients with recurrent bulbar urethral strictures who are unfit for or who refuse urethroplasty. However, they have limitations; the search for an ideal urethral stent continues. ª 2013 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Introduction Egypt, from August 2008 to November 2011. The study was reviewed and approved by the hospital ethics com- mittee. The study included a heterogeneous group of 23 A urethral stricture results from a scarring process that men who presented with symptoms of BOO due to a affects the anterior urethra, with subsequent spongiofi- recurrent urethral stricture. Most of the patients had brosis that is gradually progressive and results in a de- undergone dilatation or DVIU and urethroplasty. crease in the diameter of the urethral lumen. Patients The study included patients who had a recurrent usually start to complain of obstructive symptoms, stricture of the bulbar urethra, referred to treatment, according to the severity of the obliteration [1,2]. that was 50 mm long on urethrography and with A definitive diagnosis can be made with an ascending 10 mm of healthy urethral tissue distal to the external urethrogram coupled with diagnostic cystoscopy [3]. sphincter. Patients were excluded if there was <10 mm The use of ultrasonography has been advocated as a reli- of visibly healthy bulbar urethral tissue distal to the able method to define the extent of spongiofibrosis and external sphincter, or any urological condition that the absolute length of the urethral stricture [4]. would require additional urethral instrumentation, e.g. The treatment plan for a urethral stricture includes BPH requiring treatment, active prostate cancer, blad- variable options, e.g. dilatation, urethrotomy, stenting der malignancy, or recurrent urinary stone formation. and reconstructive surgical techniques, and no one tech- Patients were counselled about their condition and nique is appropriate for all stricture diseases [5]. the possible management options. Patients who chose Urethral dilatation alone or coupled with direct visual stent insertion were informed about possible complica- internal urethrotomy (DVIU) is not curative in all cases, tions and disadvantages. Written informed consent but can be in selected patients [6]. DVIU is especially was obtained from all patients. suitable for a short stricture in the bulbar urethra with no spongiofibrosis, has high failure rates when the Preoperative preparation stricture is long, and should not be used in the penile ure- thra. Also, several failed DVIU procedures compromise All patients had a history taken, a general and local the chances of success in a future urethroplasty [5]. Ure- examination, preoperative laboratory tests and retro- throplasty remains the best option, with higher success grade urethrography, uroflowmetry, an estimate of their rates and a satisfactory outcome, when indicated [6]. postvoid residual (PVR) urine volume, and urethros- Urethral stents are another method used to oppose copy at the time of the stent insertion. the forces of wound contraction after internal urethrot- omy or dilatation. Removable urethral stents are de- Instrumentation signed to prevent the process of epithelialisation from incorporating the stent into the urethral wall, and are of- The thermo-expandable stent (Memokath MK044, ten left in place for up to 6–12 months before they are Pnn Medical, Kvistgaard, Denmark) for bulbar urethral removed. Table 1 [7–18] shows the indications, compli- strictures was used; this is a temporary stent, made of a cations and success rates of different types of stents, as nickel–titanium alloy that has a ‘shape memory’ feature given in previous reports. [8]. This alloy is present in two crystalline forms, the more A thermo-expandable stent with an ‘inherited’ shape rigid form holding the memorised shape of the Memo- memory, made of Nitinol, has been assessed in many kath at body temperature and higher. The other form is studies in the USA, assessing its efficacy as a temporary softer and pliable; transition to this form takes place treatment for urethral strictures [7]. In the present study when the alloy is cooled to 10 C [19]. The stent is avail- we assessed the role of temporary thermo-expandable able in lengths from 30 to 70 mm in intervals of 10 mm. It urethral stents in maintaining urethral patency in pa- expands from 24 to 44 F at its proximal end, forming a tients with a recurrent bulbar urethral stricture. cone that fixes it to the urethra and prevents migration. Patients and methods Operative procedure This study was conducted in the Urology department of The operating table for insertion should have available Menoufiya University Hospital, Menoufiya University, urethral dilators (up to 26 F), a guidewire (0.09 mm, Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures 87 Table 1 Indications, complications and success rates of different types of stents in previous studies. Study No. of Stent type Indication Complications, n or n (%) Mean follow-up Success, n or patients (months) n (%) UTI Encrustation Migration Hyperplasia [9] 175 Urolume BUS 15 (11) NS 7 (4) All had ES 24 163 (93) [11] 29 Memokath DSD 10 (35) 14 (48) 7 (24) NS 21 NS [12] 8 Medinvent wallstent BUS NS NS NS All had ES 8 NS [7] 18 Metallic coil self-expanding BUS 7 (39) No NS No 8 17 (94) [13] 20 Expandable titanium BPH & BUS No No No No 12 15 (75) [14] 7 Medinvent wallstent BUS NS NS NS 4 23–31 3 [15] 49 Memotherm 25 BPH 21 BUS-otomy NS NS NS 2 (4) 24 45 (91) [16] 12 Medinvent wallstent DSD No No No No 60 5 [10] 60 Urolume BUS NS NS NS NS 45.6 52 (87) [8] 211 Memokath BPH (6) No (13) NS 96 (63) [18] 13 Urolume Posterior US 5 NS 2 NS 18 7 [17] 10 Memokath BUS 2 2 3 2 12 5 (B)US, (bulbar) urethral stricture; NS, not specified; ES, encrustation of the stent. 0.038 inch) with a straight tip, a 50 mL plastic syringe, a the tip of the stent. Under direct vision, while the outer thermometer, two markers and a ruler. An antibiotic sheath is steady, the joined inner sheath and the cysto- was administered intravenously before the procedure. scope lens are gently retracted from the outer sheath un- Most patients received spinal anaesthesia and some re- til the black connector at the tip of the introducer is ceived local anaesthesia with intra-urethral 2% lidocaine outside the stent. The stent was then released [8]. The gel 5–10 min before the procedure, and a mild sedative procedure was done as ‘one-day’ surgery. (midazolam) at a dose of 0.03 mg/kg given slowly over at least 2 min [20]. The patients were placed in the lithot- Follow-up omy position, prepared and draped appropriately; cy- sto-urethroscopy was used to assess the site of the An antibiotic was administered intravenously for 3 days urethral stricture and exclude the presence of stones or after the procedure, and then oral antibiotics for 7 days; neoplasia. analgesics were given on demand [21]. Patients were dis- The urethral strictures were treated by internal ure- charged after taking a control plain film, uroflowmetry throtomy to a minimum diameter of 26 F, then the and an estimate of the PVR, to ensure the appropriate length of the stricture assessed to define the appropriate position and function of the stent. The patients were length of the Memokath stent, based on the estimated asked to take vitamin C to acidify their urine and thus stricture length plus 2.0 cm to allow for a 10-mm overlap decrease the incidence of encrustation. Patients were fol- at either end of the stricture. The three retaining straps lowed up by uroflowmetry, urine analysis and plain from the Memokath transport shell were removed using radiography at 2 weeks after the procedure and then a scalpel, the transport shells removed from the stent every 3 months for the first year, and then every delivery system, and the mandrel was pushed out of 6 months. the delivery system, by inserting the cystoscope lens into For stent removal the patients had local intra-urethral the hub of the delivery system. The locking collar at the anaesthesia as noted above. Cold saline (5–10 C) was base of the insertion sheath was then rotated clockwise. used as the irrigant, and diagnostic cysto-urethroscopy A soft rubber ring inside the collar is compressed to cre- was used to check the distal end of the Memokath stent. ate a watertight junction between the sheath and the cys- The tip of the stent was grasped by forceps and pulled toscope lens. Sterile water or saline is connected at distally, then released turn-by-turn linearly (Figs. 1 and 635 C to the stopcock and the light source is mounted. 2) [19]. The stent, on its introducing sheath, is mounted onto the cystoscope so that the tip of the cystoscope is clear of the Results stent by 2–3 mm, the cystoscope is advanced until the tip passes 1 cm proximal to the proximal end of the stric- The mean (SD) age of the 23 patients with a recurrent ture, then 50 mL of hot water (50 C) is flushed through bulbar urethral stricture was 55.4 (7.3) years. All the cystoscope. This expands the proximal 4–6 mm into patients had a history of DVIU, dilatations and urethro- a cone shape (44 F) which ‘locks’ the stent into position. plasties. The mean (SD, range) preoperative flow rate The stent is released from the sheath when the cysto- was 4.6 (1.2, 3–7) mL/s and the preoperative PVR vol- scope lens is withdrawn from the black connector at ume was 165 (19, 130–190) mL. The mean (SD) stricture 88 Abdallah et al. managed conservatively, with no stent removal required. Urethral hyperplasia was noted in two patients (8%) who presented with lower urinary tract obstructive symptoms, and the diagnosis was confirmed by cystos- copy; they required removal of the stents. Three patients (13%) had obstructed stents due to encrustation during the first 6 months, and needed lithotripsy to clear the encrustation, which failed in one and the stent was ex- changed (Fig. 2). In five patients (22%) the stent mi- grated, requiring exchange and correctly positioned new stents (Fig. 3). Two patients felt uncomfortable with the stent and had their stent removed at their re- quest. Two patients were free of delayed complications. The mean (SD) follow-up was 17.4 (6.1) months. Thus overall, 10 patients (43%) developed complications Figure 1 Impact of the stent rings on the urethra. (migration, urethral hyperplasia and encrustation) that required intervention. Discussion Urethral stents were first introduced in 1980 by Fabian [22] for treating infravesical obstruction due to BPH. Subsequently, the indications were expanded to include the treatment of detrusor sphincter dyssynergia (DSD) due to spinal cord injury and, in 1988, the treatment of urethral strictures [23]. Thermo-expandable urethral stents were first introduced by Soni et al. [24] to treat pa- tients with DSD. In the present series, 23 patients with recurrent bulbar urethral strictures were treated with the Memokath ther- mo-expandable urethral stent. The insertion of these stents was simple and minimally invasive, comparable with dilatation and DVIU. Unfortunately the stents Figure 2 Stent removal. failed to give good results during the long-term follow- up. This situation might differ in the near future, as there are further reports of urethroplasty and its accept- length was 3.6 (1.2) cm. The procedure was done under able results [25,26]. spinal anaesthesia in 18 patients (78%) and with intra- The main indications for their use are recurrent bulbar urethral xylocaine gel and a mild sedative in five urethral strictures after failure of several previous ure- (22%). The mean (SD) operative duration was 34 (9) throplasties and DVIUs, or in patients with medical min. comorbidities who are unfit for major surgery, or for All patients tolerated the stent, with minimal discom- those who refuse urethroplasty [27]. In the present study fort in some patients. Perineal pain occurred in six pa- the original cause of the stricture had no effect on the tients (26%) that was transient and disappeared within decision to insert a stent or on the incidence of complica- a few weeks of follow-up. The urinary flow rate im- tions. This was similar to the results reported by Palmin- proved after stent insertion, to a mean (SD, range) of teri et al. [28] in their study of the management of 21 (2.5, 17–25) mL/s. The PVR volume decreased after patients with failed urethral stents. There was an appro- stent insertion to 50 (14, 30–70) mL. priate stent position and function in all the present pa- Four patients (17%) had UTIs twice or three times tients immediately after stent insertion, with an during the first 3 months of follow-up, and these were improvement in the flow rate and PVR. Also, Perry controlled by appropriate antibiotics, according to urine et al. [8] reported that most patients treated with the culture and antibiotic-sensitivity tests. Three patients Memokath stent for BOO of the prostatic urethra voided (13%) had intermittent gross haematuria during the first immediately after the procedure, so that the outcome of 2 weeks after insertion. The haematuria was initially stent placement was immediately apparent. Recurrent painful; one patient complained of the presence of a UTI was noted in 17% of the present 23 patients, which few drops of blood at the urethral meatus, and was was lower than the rate observed by Badlani et al. [9], Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures 89 Figure 3 (A) A urethral stent normally placed; (B) Urethral stent migrated upwards into the prostatic urethra. who reported UTI in 27% of the 60 patients in whom a developed obstructive symptoms after 9–11 months. Urolume stent was inserted and who were followed for This was managed by transurethral resection after stent 2 years. This difference might be due to the small sample removal. This rate was slightly lower than that reported size and the short follow-up in our study (the mean fol- by Badlani et al. [9] in their study of the Urolume stent low-up was 17.4 months). The incidence of UTI might (41.3%). The narrowing was the result of urethral epithe- be attributed to a previous history of UTI, together with lium overgrowth through the interstices of the stent. The a prolonged obstructed urinary flow and the presence of low incidence of urethral hyperplasia with the Memo- the stent as a foreign body. All these factors predispose kath stent was attributed to the tight coiling of the stent, to a high incidence of UTI that also might be resistant the inert property of the nickel–titanium alloy from to treatment. Haematuria was present in 13% of the which it is made, and the short duration of indwelling. present patients, a higher rate than reported by Perry Yachia [29] reported that with the current urethral stents, et al. [8] of 3% in their cases. This was explained by other than the Memokath, occasional tissue ingrowth be- the previous DVIU done during stent insertion, and tween the loops of the coils, and reactive tissue prolifer- added vigorous perineal trauma (as during riding a bicy- ation at the sphincter end, can cause partial or complete cle). Although the Memokath stent has a funnel shape at obliteration of the stent. The reason for such reactive one end to resist migration, the stent migrated in 22% of tissue proliferation is that the radial stiffness of the present patients (five of 23). Migration was related to the sphincter end of the stent causes repeated friction accidental perineal trauma, a faulty trial of catheterisa- to the urethral wall during opening and closing of the tion, and the presence of the stricture close to the sphinc- sphincter. Also, Eisenberg et al. [18] found that the most ter. This was a higher rate than reported by Perry et al. common surgical interventions required for failed ure- [8], who had stent migration in 13% of their cases (29 pa- thral stent were transurethral resection of the hyperplasia tients of 211), and because the Urolume stents do not mi- (32%) and endoscopic litholapaxy for stent encrustation grate due to their incorporation into the wall of the or stones (17%). urethra [10]. In the present study the occurrence of complications Obstructive symptoms and a decreased flow rate were increased with time. The mean (SD) period for encrusta- reported in eight of the present patients (35%). The tion was 9.8 (2) months, while that of hyperplasia was 10 symptoms became gradually more severe over 6– (1.4) months, and that for migration was 10 (3) months. 9 months. Encrustation was noted in five of these pa- With an increasing follow-up the stents tended to have a tients, that necessitated urethroscopy and lithotripsy to high failure rate that ultimately required removal of the remove the encrusted material. Perry et al. [8] found stents in 35% of the patients after a mean (SD) period of encrustation in 2% of their cases (five of 211) and men- 9 (3) months. This period was shorter than that reported tioned that the reason for the lack of encrustation on by Chapple and Bhargava [27] in their study on manag- these stents was not known, but was attributed to the ing the failure of a permanently implanted urethral exceptional smoothness of the surface of the stent and stent, as the mean (range) duration for the stents to re- the inert property of the alloy. Encrustation in the pres- main in situ before their removal due to failure was 26 ent patients was attributed to the higher incidence of UTI (3–85) months. This suggested to us that the Memokath and the prolonged obstruction of urinary flow. Also, stent was best reserved for use as a temporary stent and noncompliance of some patients with the prescribed not for permanent use. medications for urine acidification predisposed them to The failure rate in our study was 52% (12 patients) encrustation. Urethral hyperplasia was noted at the ends and of these, eight stents were removed due to complica- of the stent in two patients (8%) who gradually tions, for migration in five, in one for encrustation, in 90 Abdallah et al. [9] Badlani GH, Press SM, Defalco A, Oesterling JE, Smith AD. two for urethral hyperplasia and in four as the patients Urolume endourethral prosthesis for the treatment of urethral were unwilling to continue with the stent. This rate was stricture disease: long-term results of the North American similar to that reported by Mehta and Tophill [11].We Multicenter UroLume Trial. Urology 1995;45:846–56. had no difficulty in removing the Memokath stents, [10] Sertcelik N, Sagnak L, Imamoglu A, Temel M, Tuygun C. The which might be attributed to the synthetic nature of use of self-expanding metallic urethral stents in the treatment of recurrent bulbar urethral strictures: long-term results. BJU Int the stents and the short period of insertion. This con- 2000;86:686–9. trasts with the report by Elkassaby et al. [30], that fail- [11] Mehta SS, Tophill PR. Memokath stents for the treatment of ure of a permanently implanted urethral stent detrusor sphincter dyssynergia (DSD) in men with spinal cord represents a significant therapeutic challenge, which of- injury: the Princess Royal Spinal Injuries Unit 10-year experience. ten leads to a difficult substitution procedure, with con- Spinal cord 2006;44:1–6. [12] Milroy E. Stents in therapy of urethral strictures. Urologe A sequent limitation of the success of the procedure. As 1998;37:51–5. permanent urethral stents tend to be incorporated into [13] Boullier JA, Parra RO. Prostatic titanium urethral stents. A new the wall of the urethra, this hinders their removal. treatment option for obstructive uropathy: early clinical results In conclusion, we recommend only the temporary use and indications. ASAIO Trans 1991;37:M297–8. of thermo-expandable (Memokath) stents for patients [14] Baert L, Verhamme L, Van Poppel H, Vandeursen H, Baert J. Long-term consequences of urethral stents. J Urol with previously failed urethroplasties who refuse further 1993;150:853–5. surgical management, or those who are medically unfit [15] Ricciotti G, Bozzo W, Perachino M, Pezzica C, Puppo P. Heat- for urethroplasty. The long-term results of the Memo- expansible permanent intraurethral stents for benign prostatic kath stent were not encouraging and the patients had hyperplasia and urethral strictures. J Endourol 1995;9:417–22. complications related to the stent; they are also expen- [16] McFarlane IP, Foley SJ, Shah PJ. Long-term outcome of permanent urethral stents in the treatment of detrusor-sphincter sive. The use of these stents was associated with compli- dyssynergia. Br J Urol 1996;78:729–32. cations that sometimes required exchange or removal of [17] Abdallah M, Bissada NM. Experience with urethral stents for the stent. The overall experience with Memokath stents recurrent urethral stricture. Urology 2009;74:S87–8. was disappointing, and thus we use this stent only with [18] Eisenberg ML, Elliott SP, McAninch JW. Preservation of lower highly selected patients, as noted, and do not use them urinary tract function in posterior urethral stenosis: selection of appropriate patients for urethral stents. J Urol 2007;178:2456–60. when urethral reconstruction is feasible. [19] Barber NJ, Roodhouse AJ, Rathenborg P, Nordling J, Ellis BW. Ease of removal of thermo-expandable prostate stents. BJU Int Conflict of interest 2005;96:578–80. [20] Song YS, Song ES, Kim KJ, Park YH, Ku JH. Midazolam anesthesia during rigid and flexible cystoscopy. Urol Res No conflict of interest. 2007;35:139–42. [21] Turan H, Balci U, Erdinc FS, Tulek N, Germiyanoglu C. Source of Funding Bacteriuria, pyuria and bacteremia frequency following outpa- tient cystoscopy. Int J Urol 2006;13:25–8. [22] Fabian KM. The intra-prostatic ‘partial catheter’ (urological None. spiral) (author’s transl). Urologe A 1980;19:236–8. [23] Milroy EJ, Chapple CR, Cooper JE, Eldin A, Wallsten H, Seddon References AM, et al. A new treatment for urethral strictures. Lancet 1988;1:1424–7. [1] Bhargava S, Chapple CR. Buccal mucosal urethroplasty: is it the [24] Soni BM, Vaidyanatham S, Krishnan KR. Use of Memokath, a new gold standard? 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Management of urethral stricture permanently implanted urethral stent––a therapeutic challenge. disease: developing options for surgical intervention. BJU Int Eur Urol 2008;54:665–70. 2004;94:971–6. [28] Palminteri E, Gacci M, Berdondini E, Poluzzi M, Franco G, [6] Andrich DE, Mundy AR. Urethral strictures and their surgical Gentile V. Management of urethral stent failure for recurrent treatment. BJU Int 2000;86:571–80. anterior urethral strictures. Eur Urol 2010;57:615–21. [7] Yachia D, Beyar M. Temporarily implanted urethral coil stent for [29] Yachia D. Recent advances in ureteral stents. Curr Opin Urol the treatment of recurrent urethral strictures: a preliminary 2008;18:241–6. report. J Urol 1991;146:1001–4. [30] Elkassaby AA, Al-Kandari AM, Shokeir AA. The surgical [8] Perry MJ, Roodhouse AJ, Gidlow AB, Spicer TG, Ellis BW. management of obstructive stents used for urethral strictures. J Thermo-expandable intraprostatic stents in bladder outlet Urol 2007;178:204–7. obstruction: an 8-year study. BJU Int 2002;90:216–23. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arab Journal of Urology Taylor & Francis

Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not?

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Arab Journal of Urology (2013) 11,85–90 Arab Journal of Urology (Official Journal of the Arab Association of Urology) www.sciencedirect.com STONES/ENDOUROLOGY ORIGINAL ARTICLE Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not? Mohamed M. Abdallah , Mohamed Selim, Tarek Abdelbakey Urology Department, Menoufiya University Hospital, Menoufiya, Egypt Received 18 November 2012, Received in revised form 17 December 2012, Accepted 18 December 2012 Available online 24 January 2013 KEYWORDS Abstract Objectives: To assess the role of temporary thermally expandable urethral stents in maintaining urethral patency in patients with a recurrent bulbar Bulbar urethral stric- urethral stricture. ture; Patients and methods: Twenty-three men with a recurrent bulbar urethral Stents; stricture after several attempts at direct visual internal urethrotomy (DVIU) and/ Recurrent stricture or failed urethroplasty were managed with a thermally expandable, biocom- patible nickel–titanium alloy urethral stent (Memokath MK044, Pnn Medical, ABBREVIATIONS Kvistgaard, Denmark). The stents were applied by a special mounting device via a DSD, detrusor sphinc- rigid urethroscope after DVIU. All patients were followed using plain radiography, ter dyssynergia; DVIU, uroflowmetry and urine analysis every 3 months for 1 year, and then every 6 months. direct visual internal Results: The mean (SD) age of the patients was 55.4 (7.3) years and the mean urethrotomy; PVR, (SD) stricture length was 3.6 (1.2) cm. All patients tolerated the stent, with minimal postvoid residual discomfort in some patients. Four patients (17%) had urinary tract infections, three (urine) (13%) had haematuria, three (13%) had obstructed stents due to encrustation, in five (22%) the stent migrated, and two patients had no delayed complications. The mean (SD) follow-up was 17.4 (6.1) months. Corresponding author. Address: Department of Urology, Faculty of Medicine, Shibin Elkom, Minofia, Egypt. Tel.: +20 1003413438. E-mail address: mmarzouk@yahoo.com (M.M. Abdallah). Peer review under responsibility of Arab Association of Urology. Production and hosting by Elsevier 2090-598X ª 2013 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.aju.2012.12.005 86 Abdallah et al. Conclusion: Urethral stenting with nickel–titanium alloy thermally expandable stents can be an acceptable temporary procedure for patients with recurrent bulbar urethral strictures who are unfit for or who refuse urethroplasty. However, they have limitations; the search for an ideal urethral stent continues. ª 2013 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Introduction Egypt, from August 2008 to November 2011. The study was reviewed and approved by the hospital ethics com- mittee. The study included a heterogeneous group of 23 A urethral stricture results from a scarring process that men who presented with symptoms of BOO due to a affects the anterior urethra, with subsequent spongiofi- recurrent urethral stricture. Most of the patients had brosis that is gradually progressive and results in a de- undergone dilatation or DVIU and urethroplasty. crease in the diameter of the urethral lumen. Patients The study included patients who had a recurrent usually start to complain of obstructive symptoms, stricture of the bulbar urethra, referred to treatment, according to the severity of the obliteration [1,2]. that was 50 mm long on urethrography and with A definitive diagnosis can be made with an ascending 10 mm of healthy urethral tissue distal to the external urethrogram coupled with diagnostic cystoscopy [3]. sphincter. Patients were excluded if there was <10 mm The use of ultrasonography has been advocated as a reli- of visibly healthy bulbar urethral tissue distal to the able method to define the extent of spongiofibrosis and external sphincter, or any urological condition that the absolute length of the urethral stricture [4]. would require additional urethral instrumentation, e.g. The treatment plan for a urethral stricture includes BPH requiring treatment, active prostate cancer, blad- variable options, e.g. dilatation, urethrotomy, stenting der malignancy, or recurrent urinary stone formation. and reconstructive surgical techniques, and no one tech- Patients were counselled about their condition and nique is appropriate for all stricture diseases [5]. the possible management options. Patients who chose Urethral dilatation alone or coupled with direct visual stent insertion were informed about possible complica- internal urethrotomy (DVIU) is not curative in all cases, tions and disadvantages. Written informed consent but can be in selected patients [6]. DVIU is especially was obtained from all patients. suitable for a short stricture in the bulbar urethra with no spongiofibrosis, has high failure rates when the Preoperative preparation stricture is long, and should not be used in the penile ure- thra. Also, several failed DVIU procedures compromise All patients had a history taken, a general and local the chances of success in a future urethroplasty [5]. Ure- examination, preoperative laboratory tests and retro- throplasty remains the best option, with higher success grade urethrography, uroflowmetry, an estimate of their rates and a satisfactory outcome, when indicated [6]. postvoid residual (PVR) urine volume, and urethros- Urethral stents are another method used to oppose copy at the time of the stent insertion. the forces of wound contraction after internal urethrot- omy or dilatation. Removable urethral stents are de- Instrumentation signed to prevent the process of epithelialisation from incorporating the stent into the urethral wall, and are of- The thermo-expandable stent (Memokath MK044, ten left in place for up to 6–12 months before they are Pnn Medical, Kvistgaard, Denmark) for bulbar urethral removed. Table 1 [7–18] shows the indications, compli- strictures was used; this is a temporary stent, made of a cations and success rates of different types of stents, as nickel–titanium alloy that has a ‘shape memory’ feature given in previous reports. [8]. This alloy is present in two crystalline forms, the more A thermo-expandable stent with an ‘inherited’ shape rigid form holding the memorised shape of the Memo- memory, made of Nitinol, has been assessed in many kath at body temperature and higher. The other form is studies in the USA, assessing its efficacy as a temporary softer and pliable; transition to this form takes place treatment for urethral strictures [7]. In the present study when the alloy is cooled to 10 C [19]. The stent is avail- we assessed the role of temporary thermo-expandable able in lengths from 30 to 70 mm in intervals of 10 mm. It urethral stents in maintaining urethral patency in pa- expands from 24 to 44 F at its proximal end, forming a tients with a recurrent bulbar urethral stricture. cone that fixes it to the urethra and prevents migration. Patients and methods Operative procedure This study was conducted in the Urology department of The operating table for insertion should have available Menoufiya University Hospital, Menoufiya University, urethral dilators (up to 26 F), a guidewire (0.09 mm, Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures 87 Table 1 Indications, complications and success rates of different types of stents in previous studies. Study No. of Stent type Indication Complications, n or n (%) Mean follow-up Success, n or patients (months) n (%) UTI Encrustation Migration Hyperplasia [9] 175 Urolume BUS 15 (11) NS 7 (4) All had ES 24 163 (93) [11] 29 Memokath DSD 10 (35) 14 (48) 7 (24) NS 21 NS [12] 8 Medinvent wallstent BUS NS NS NS All had ES 8 NS [7] 18 Metallic coil self-expanding BUS 7 (39) No NS No 8 17 (94) [13] 20 Expandable titanium BPH & BUS No No No No 12 15 (75) [14] 7 Medinvent wallstent BUS NS NS NS 4 23–31 3 [15] 49 Memotherm 25 BPH 21 BUS-otomy NS NS NS 2 (4) 24 45 (91) [16] 12 Medinvent wallstent DSD No No No No 60 5 [10] 60 Urolume BUS NS NS NS NS 45.6 52 (87) [8] 211 Memokath BPH (6) No (13) NS 96 (63) [18] 13 Urolume Posterior US 5 NS 2 NS 18 7 [17] 10 Memokath BUS 2 2 3 2 12 5 (B)US, (bulbar) urethral stricture; NS, not specified; ES, encrustation of the stent. 0.038 inch) with a straight tip, a 50 mL plastic syringe, a the tip of the stent. Under direct vision, while the outer thermometer, two markers and a ruler. An antibiotic sheath is steady, the joined inner sheath and the cysto- was administered intravenously before the procedure. scope lens are gently retracted from the outer sheath un- Most patients received spinal anaesthesia and some re- til the black connector at the tip of the introducer is ceived local anaesthesia with intra-urethral 2% lidocaine outside the stent. The stent was then released [8]. The gel 5–10 min before the procedure, and a mild sedative procedure was done as ‘one-day’ surgery. (midazolam) at a dose of 0.03 mg/kg given slowly over at least 2 min [20]. The patients were placed in the lithot- Follow-up omy position, prepared and draped appropriately; cy- sto-urethroscopy was used to assess the site of the An antibiotic was administered intravenously for 3 days urethral stricture and exclude the presence of stones or after the procedure, and then oral antibiotics for 7 days; neoplasia. analgesics were given on demand [21]. Patients were dis- The urethral strictures were treated by internal ure- charged after taking a control plain film, uroflowmetry throtomy to a minimum diameter of 26 F, then the and an estimate of the PVR, to ensure the appropriate length of the stricture assessed to define the appropriate position and function of the stent. The patients were length of the Memokath stent, based on the estimated asked to take vitamin C to acidify their urine and thus stricture length plus 2.0 cm to allow for a 10-mm overlap decrease the incidence of encrustation. Patients were fol- at either end of the stricture. The three retaining straps lowed up by uroflowmetry, urine analysis and plain from the Memokath transport shell were removed using radiography at 2 weeks after the procedure and then a scalpel, the transport shells removed from the stent every 3 months for the first year, and then every delivery system, and the mandrel was pushed out of 6 months. the delivery system, by inserting the cystoscope lens into For stent removal the patients had local intra-urethral the hub of the delivery system. The locking collar at the anaesthesia as noted above. Cold saline (5–10 C) was base of the insertion sheath was then rotated clockwise. used as the irrigant, and diagnostic cysto-urethroscopy A soft rubber ring inside the collar is compressed to cre- was used to check the distal end of the Memokath stent. ate a watertight junction between the sheath and the cys- The tip of the stent was grasped by forceps and pulled toscope lens. Sterile water or saline is connected at distally, then released turn-by-turn linearly (Figs. 1 and 635 C to the stopcock and the light source is mounted. 2) [19]. The stent, on its introducing sheath, is mounted onto the cystoscope so that the tip of the cystoscope is clear of the Results stent by 2–3 mm, the cystoscope is advanced until the tip passes 1 cm proximal to the proximal end of the stric- The mean (SD) age of the 23 patients with a recurrent ture, then 50 mL of hot water (50 C) is flushed through bulbar urethral stricture was 55.4 (7.3) years. All the cystoscope. This expands the proximal 4–6 mm into patients had a history of DVIU, dilatations and urethro- a cone shape (44 F) which ‘locks’ the stent into position. plasties. The mean (SD, range) preoperative flow rate The stent is released from the sheath when the cysto- was 4.6 (1.2, 3–7) mL/s and the preoperative PVR vol- scope lens is withdrawn from the black connector at ume was 165 (19, 130–190) mL. The mean (SD) stricture 88 Abdallah et al. managed conservatively, with no stent removal required. Urethral hyperplasia was noted in two patients (8%) who presented with lower urinary tract obstructive symptoms, and the diagnosis was confirmed by cystos- copy; they required removal of the stents. Three patients (13%) had obstructed stents due to encrustation during the first 6 months, and needed lithotripsy to clear the encrustation, which failed in one and the stent was ex- changed (Fig. 2). In five patients (22%) the stent mi- grated, requiring exchange and correctly positioned new stents (Fig. 3). Two patients felt uncomfortable with the stent and had their stent removed at their re- quest. Two patients were free of delayed complications. The mean (SD) follow-up was 17.4 (6.1) months. Thus overall, 10 patients (43%) developed complications Figure 1 Impact of the stent rings on the urethra. (migration, urethral hyperplasia and encrustation) that required intervention. Discussion Urethral stents were first introduced in 1980 by Fabian [22] for treating infravesical obstruction due to BPH. Subsequently, the indications were expanded to include the treatment of detrusor sphincter dyssynergia (DSD) due to spinal cord injury and, in 1988, the treatment of urethral strictures [23]. Thermo-expandable urethral stents were first introduced by Soni et al. [24] to treat pa- tients with DSD. In the present series, 23 patients with recurrent bulbar urethral strictures were treated with the Memokath ther- mo-expandable urethral stent. The insertion of these stents was simple and minimally invasive, comparable with dilatation and DVIU. Unfortunately the stents Figure 2 Stent removal. failed to give good results during the long-term follow- up. This situation might differ in the near future, as there are further reports of urethroplasty and its accept- length was 3.6 (1.2) cm. The procedure was done under able results [25,26]. spinal anaesthesia in 18 patients (78%) and with intra- The main indications for their use are recurrent bulbar urethral xylocaine gel and a mild sedative in five urethral strictures after failure of several previous ure- (22%). The mean (SD) operative duration was 34 (9) throplasties and DVIUs, or in patients with medical min. comorbidities who are unfit for major surgery, or for All patients tolerated the stent, with minimal discom- those who refuse urethroplasty [27]. In the present study fort in some patients. Perineal pain occurred in six pa- the original cause of the stricture had no effect on the tients (26%) that was transient and disappeared within decision to insert a stent or on the incidence of complica- a few weeks of follow-up. The urinary flow rate im- tions. This was similar to the results reported by Palmin- proved after stent insertion, to a mean (SD, range) of teri et al. [28] in their study of the management of 21 (2.5, 17–25) mL/s. The PVR volume decreased after patients with failed urethral stents. There was an appro- stent insertion to 50 (14, 30–70) mL. priate stent position and function in all the present pa- Four patients (17%) had UTIs twice or three times tients immediately after stent insertion, with an during the first 3 months of follow-up, and these were improvement in the flow rate and PVR. Also, Perry controlled by appropriate antibiotics, according to urine et al. [8] reported that most patients treated with the culture and antibiotic-sensitivity tests. Three patients Memokath stent for BOO of the prostatic urethra voided (13%) had intermittent gross haematuria during the first immediately after the procedure, so that the outcome of 2 weeks after insertion. The haematuria was initially stent placement was immediately apparent. Recurrent painful; one patient complained of the presence of a UTI was noted in 17% of the present 23 patients, which few drops of blood at the urethral meatus, and was was lower than the rate observed by Badlani et al. [9], Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures 89 Figure 3 (A) A urethral stent normally placed; (B) Urethral stent migrated upwards into the prostatic urethra. who reported UTI in 27% of the 60 patients in whom a developed obstructive symptoms after 9–11 months. Urolume stent was inserted and who were followed for This was managed by transurethral resection after stent 2 years. This difference might be due to the small sample removal. This rate was slightly lower than that reported size and the short follow-up in our study (the mean fol- by Badlani et al. [9] in their study of the Urolume stent low-up was 17.4 months). The incidence of UTI might (41.3%). The narrowing was the result of urethral epithe- be attributed to a previous history of UTI, together with lium overgrowth through the interstices of the stent. The a prolonged obstructed urinary flow and the presence of low incidence of urethral hyperplasia with the Memo- the stent as a foreign body. All these factors predispose kath stent was attributed to the tight coiling of the stent, to a high incidence of UTI that also might be resistant the inert property of the nickel–titanium alloy from to treatment. Haematuria was present in 13% of the which it is made, and the short duration of indwelling. present patients, a higher rate than reported by Perry Yachia [29] reported that with the current urethral stents, et al. [8] of 3% in their cases. This was explained by other than the Memokath, occasional tissue ingrowth be- the previous DVIU done during stent insertion, and tween the loops of the coils, and reactive tissue prolifer- added vigorous perineal trauma (as during riding a bicy- ation at the sphincter end, can cause partial or complete cle). Although the Memokath stent has a funnel shape at obliteration of the stent. The reason for such reactive one end to resist migration, the stent migrated in 22% of tissue proliferation is that the radial stiffness of the present patients (five of 23). Migration was related to the sphincter end of the stent causes repeated friction accidental perineal trauma, a faulty trial of catheterisa- to the urethral wall during opening and closing of the tion, and the presence of the stricture close to the sphinc- sphincter. Also, Eisenberg et al. [18] found that the most ter. This was a higher rate than reported by Perry et al. common surgical interventions required for failed ure- [8], who had stent migration in 13% of their cases (29 pa- thral stent were transurethral resection of the hyperplasia tients of 211), and because the Urolume stents do not mi- (32%) and endoscopic litholapaxy for stent encrustation grate due to their incorporation into the wall of the or stones (17%). urethra [10]. In the present study the occurrence of complications Obstructive symptoms and a decreased flow rate were increased with time. The mean (SD) period for encrusta- reported in eight of the present patients (35%). The tion was 9.8 (2) months, while that of hyperplasia was 10 symptoms became gradually more severe over 6– (1.4) months, and that for migration was 10 (3) months. 9 months. Encrustation was noted in five of these pa- With an increasing follow-up the stents tended to have a tients, that necessitated urethroscopy and lithotripsy to high failure rate that ultimately required removal of the remove the encrusted material. Perry et al. [8] found stents in 35% of the patients after a mean (SD) period of encrustation in 2% of their cases (five of 211) and men- 9 (3) months. This period was shorter than that reported tioned that the reason for the lack of encrustation on by Chapple and Bhargava [27] in their study on manag- these stents was not known, but was attributed to the ing the failure of a permanently implanted urethral exceptional smoothness of the surface of the stent and stent, as the mean (range) duration for the stents to re- the inert property of the alloy. Encrustation in the pres- main in situ before their removal due to failure was 26 ent patients was attributed to the higher incidence of UTI (3–85) months. This suggested to us that the Memokath and the prolonged obstruction of urinary flow. Also, stent was best reserved for use as a temporary stent and noncompliance of some patients with the prescribed not for permanent use. medications for urine acidification predisposed them to The failure rate in our study was 52% (12 patients) encrustation. Urethral hyperplasia was noted at the ends and of these, eight stents were removed due to complica- of the stent in two patients (8%) who gradually tions, for migration in five, in one for encrustation, in 90 Abdallah et al. [9] Badlani GH, Press SM, Defalco A, Oesterling JE, Smith AD. two for urethral hyperplasia and in four as the patients Urolume endourethral prosthesis for the treatment of urethral were unwilling to continue with the stent. This rate was stricture disease: long-term results of the North American similar to that reported by Mehta and Tophill [11].We Multicenter UroLume Trial. 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Journal

Arab Journal of Urology – Taylor & Francis

Published: Mar 1, 2013

Keywords: Bulbar urethral stricture; Stents; Recurrent stricture; DSD, detrusor sphincter dyssynergia; DVIU, direct visual internal urethrotomy; PVR, postvoid residual (urine)

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