Endoscopic removal of a proximal urethral stent using a holmium laser: Case report and literature review.

Urethral stents were initially developed for the management of urethral strictures and obstructive voiding disorders in select patients. Urethral stent complications are common and may require stent explantation, which is often quite challenging. We present our experience with endoscopic removal of an encrusted UroLume proximal urethral stent in a 72-year-old male using a holmium laser. The literature on various management options and outcomes for urethral stent removal is reviewed. Endoscopic removal of proximal urethral stents is feasible and safe and should be considered as the primary treatment option in patients requiring stent extraction.

INTRODUCTION

Urethral stents have been used for the treatment of various urethral pathologies including benign prostatic hyperplasia (BPH), urethral stricture disease, and detrusor-sphincter dyssynergia (DSD).[1] They can be categorized as permanent or temporary, according to their ability to promote epithelialization and become embedded within the urethra or to be removed or biodegraded.[1] Examples of permanent urethral stents include the UroLume® (American Medical Systems, Minnetonka, Minn), also known as the Wallstent™ in Europe, Titan®, and Memotherm™ (Engineers and Doctors A/s, Hornbaek, Denmark).[1] In recent years there has been tempered enthusiasm for the use of urethral stents due to their associated high complication rates.[2-6] This has subsequently led to the recommendation of limiting urethral stents to patients with significant comorbidities or contraindications to definitive surgical management.[2] Unfortunately, stent extraction can be potentially quite challenging and result in significant morbidity. Furthermore, there is no current consensus on the optimal method of urethral stent removal. We report our experience with a severely encrusted prostatic urethral stent in a patient with neurogenic bladder and DSD. We also review the literature on different management options and outcomes for the removal of permanent urethral stents.

CASE REPORT

A 72-year-old man with history of neurogenic bladder presented for evaluation of recurrent urinary tract infections, obstructive voiding symptoms, and an inability to perform self-catheterization. The patient had previously sustained a T6 spinal cord injury and subsequently had a sphincterotomy and urethral stent (UroLume™) placement 10 years ago for DSD and bladder outlet obstruction. A calcified urethral stent was visualized on a plain kidney–ureter–bladder (KUB) radiograph [Figure 1] and flexible urethroscopy confirmed the presence of a severely encrusted stent at the bladder neck, which almost completely obstructed the urethral lumen [Figure 2].

Figure 1

Plain radiograph of the pelvis with calcified stent at bladder neck

Figure 2

Endoscopic view of prostatic urethra showing complete stent calcification and obstruction of bladder neck and urethral lumen

The patient subsequently underwent laser fragmentation and extraction of the calcified stent. Initially, the stone was fragmented with Ho:YAG laser, using a 550-μm fiber, allowing the stent to be partially visualized. The hyperplastic tissue covering the stent was then resected using a bipolar transurethral resection loop and the holmium laser was then used to fragment the stent into smaller segments which were cystoscopically extracted [Figure 3]. Upon completion of the procedure, the bladder outlet was patent and without any evidence of residual stent fragments [Figure 4]. The patient's prostatic urethra remained patent at 7 months follow-up and the patient resumed intermittent self-catheterization without difficulty.

Figure 3

Endoscopic image of intra-vesical stent being treated by laser fiber

Figure 4

Endoscopic view of prostatic urethra after stent removal

DISCUSSION

Despite initial enthusiasm for urethral stent placement, long-term patient follow-up has demonstrated relatively high rates of associated complications, including hyperplastic tissue growth, stent separation, stent encrustation, recurrent urinary tract infections, and recurrent urethral obstruction.[2-6] As a result, both the EAU and the AUA guidelines on BPH recommend urethral stent placement in high risk patients who are poor surgical candidates.[78] Complications involving permanently implanted urethral stents present as a significant surgical challenge as their removal may be quite complex. Furthermore, the majority of patients with urethral stents are initially selected based on their increased surgical/medical risk, and stent removal becomes a similarly problematic issue as this may require a lengthy surgical procedure.

Historically, open stent explantation with urethral reconstruction was the most common method of stent removal in patients with bulbous urethral stent failure;[49] however, both endoscopic and open techniques have been employed for proximal urethral stents.[10-12] Interestingly, proximal stents implanted for BPH and DSD were more likely to require removal in comparison to stents placed for bulbous urethral strictures.[56] Stent misplacement and stent migration were among the main causes of stent failure within proximal urethra.[101113] The UroLume multicenter study group attempted to create recommendations regarding appropriate techniques for stent removal based on the initial underlying etiology and location of urethral obstruction.[11] For patients with urethral stents placed for BPH and/or DSD, endoscopic management was recommended with resection of the overlying urothelium, advancement of the stent into the bladder, and then en bloc removal of the stent through a larger sheath.[11]

Although several studies have reported endoscopic stent removal with minimal complications, others have found endoscopic removal to be quite challenging and even impossible, resulting in significant post-operative morbidity.[6101213] Most common complications included bleeding and urethral injury.[5611] These cases are especially challenging due to the surrounding fibrosis and hyperplastic tissue growth. In addition, endoscopic equipment used for stent removal is usually barrowed from stone and BPH-specific procedure sets, and may not be optimal for urethral stents. However, as mentioned previously, the proximal urethral anatomy is quite different from bulbous urethral anatomy and is likely the reason for the frequently observed stent migration. Furthermore, permanent urethral stents form a shape of a cylinder, whereas the prostatic urethra may have an asymmetric contour and may be wider at bladder neck, resulting in inadequate initial stent positioning to the urethral wall.[5] The variation of radial forces at this anatomical location is also different from the bulbous urethra, probably contributing to poorer fixation. This may create an environment for easier endoscopic treatment of urethral stent. Also, prostatic urethra provides a safer environment for resection and laser fragmentation in comparison to the bulbous urethra simply by protection provided by the surrounding prostatic lobes.

Our case of a 10-year-old prostatic indwelling UroLume® stent represents one of the longest indwelling stents removed endoscopically in the reported literature. Similar to other reports, we found the endoscopic removal of a prostatic urethral stent to be feasible and safe. Most of the published studies are case reports and most employ a holmium laser for simultaneous treatment of hyperplastic epithelial tissue and urethral stent.[31415] However, Tseng et al advocate use of a diode laser to provide less damage to surrounding tissues and to lower the power requirement (in comparison to holmium laser).[16] In the current case, despite significant stent encrustation, simultaneous transurethral laser lithotripsy and laser fragmentation of the UroLume® stent was successfully performed using a holmium laser.

The current literature regarding urethral stent extraction is limited by small case series or case reports, and most published cases do not report long-term patient follow-up [Table 1]. However, in patients with BPH or DSD, endoscopic laser fragmentation and stent removal appears to be very tolerable in high-risk patients with no immediate or short-term post-operative failures. This should be considered as a first-line treatment in the majority of such patients. Furthermore, the laser (Ho:YAG or diode) may be used simultaneously to vaporize the epithelial tissue covering the stent, eliminating the need to repeatedly exchange instruments. In patients requiring bulbous urethral stent removal, a combined approach of open explantation with urethroplasty may still be preferred, as the majority of these patients will develop recurrent strictures.

Table 1

Literature review of permanent urethral stent removal