Medicine Section - Temporary Prostatic Stent

IMPORTANT REMINDER

Regence Medical Policies are developed to provide guidance for members and providers regarding coverage in accordance with contract terms. Benefit determinations are based in all cases on the applicable contract language. To the extent there may be any conflict between the Medical Policy and contract language, the contract language takes precedence.

PLEASE NOTE: Contracts exclude from coverage, among other things, services or procedures that are considered investigational or cosmetic. Providers may bill members for services or procedures that are considered investigational or cosmetic. Providers are encouraged to inform members before rendering such services that the members are likely to be financially responsible for the cost of these services.

Description

Prostatic obstruction is a common condition with a variety of etiologies. Benign prostatic hyperplasia (BPH) is the most common etiology, but obstruction may also occur acutely after surgical treatment for BPH, prostatic cancer or after radiation therapy. Intraprostatic stenting has been investigated as a short term treatment option permitting volitional urination as an alternative to the commonly used Foley catheter in which urine is collected in an external bag. In addition to volitional urination, the ideal temporary stent would be one that could be easily inserted and removed without migration, permitting adequate emptying of the bladder without disrupting the external sphincter such that continence could be maintained.

At the present time, there is one temporary prostatic stent that has received FDA approval. The Spanner™ Temporary Prostatic Stent (Abbeymoore Medical) received premarket application (PMA) approval from FDA on December 14, 2006 for temporary use (up to 30 days) to maintain urine flow and allow voluntary urination in patients following minimally invasive treatment of BPH and after initial post-treatment catheterization.  The Spanner™ stent is composed of a proximal balloon to prevent distal displacement, a urine port situated cephalad to the balloon and a reinforced stent of various lengths to span most of the prostatic urethra. The distal anchor is shaped like a teardrop and positioned in the distal meatus. As the patient voids, the force of the urine compresses the device against the sides of the meatus, thus minimally obstructing the urine flow. A distal anchor mechanism is attached by sutures. Finally, a retrieval suture extends to the meatus and deflates the proximal balloon when pulled. The device is inserted in an outpatient procedure under topical anesthesia.

The Cleveland Clinic Foundation began recruiting patients in November 2005 for a Phase I/II clinical trial (Identifier  NCT00252941). (2) This trial is intended to determine the feasibility, safety, and efficacy of the Memokath® 028SW urethral stent (Engineers and Doctors A/S, Copenhagen, Denmark) when used to prevent urinary obstructive symptoms after prostate seed implantation for the treatment of localized prostate cancer.  The Memokath® stent is a coil of nickel-titanium alloy which has 'shape memory', the lower end expanding when heated to 55 degrees C.  It is inserted under topical anesthesia via cystoscopy.

Note: This policy does not address the use of permanent prostatic stents. The Urolume is an example of an FDA approved permanent prostatic stent. This wire mesh device is placed into the urethra, where it is slowly incorporated into the urethral wall. This policy only addresses temporary stents, which are designed to be removable.

Policy/Criteria

A temporary prostatic stent is considered investigational.

Scientific Background

There are minimal published data regarding the Spanner™ Temporary Prostatic Stent (TPS). FDA approval of the Spanner™ TPS was based on preclinical trials and one multicenter, randomized, controlled trial which included 186 patients who had received transurethral microwave thermotherapy (TUMT) for BPH. (3,4) Immediately following post-TUMT Foley catheter removal patients were randomly assigned to either a treatment group (n=100) in which a TPS was placed or a control group (n=86) who received no additional procedure. The TPS was left in place for 28 days. Urinary tract symptoms and post void residual (PVR) were measured at one, two and four weeks following Foley catheter removal and at one and four weeks following stent removal. More adverse events were reported in the stent group except urinary retention which was more frequent in the control group. The stent group reported significantly superior improvement in symptoms at the one week follow-up visit (p=0.047) and PVR at the one and two week visits (p=0.001). Thereafter there was no significant difference between the stent and control groups. Eight (8%) patients had complications related to stent migration, expulsion and encrustation. The authors concluded that the Spanner™ TPS provided modest benefit with an acceptable amount of risk. However, these outcomes have not been duplicated in any other randomized, controlled study.

Corica and colleagues published the results of a case series of 30 patients who had obstruction of the prostatic urethra. (6) The Spanner™ stent was inserted and remained in situ for between 1 and 98 days (mean 57 days). The maximum urinary flow rate improved from 8.2 mL/s to 11.6 mL/sec, while the mean post void residual improved from 312 mL to 112.3 mL. There was temporary self limited incontinence during the first week in 11 of the 30 patients (37%). There were no significant complications. Two European research groups conducted studies for two new designs of removable stents in a total of 198 subjects. (7-9) Unsatisfactory outcomes were reported for both models; the stents required early removal due to migration and other sources of pain. Grimsley and colleagues described repeated temporary Spanner stent use in 43 consecutive patients with bladder-outlet obstruction who were unfit for surgery. (10) It was reported that 63% of the patients had unsatisfactory outcomes; the remaining 37% were considered to have had satisfactory outcomes either with a stent in situ after a mean of five changes or stent free after a successful voiding trial. The authors suggest that, in this population, a temporary stent might be reasonably used only as a trial for placement of a permanent stent. Additional study is needed to establish if use of the Spanner stent results in clinically significant improvement in health outcomes.

In summary, the available evidence is not sufficient to draw conclusions concerning the health outcome effects of TPS insertion following catheter removal after minimally invasive surgery for BPH.  Larger randomized, preferably sham-controlled studies are needed to evaluate the benefits and risks of this procedure. An updated search of the MEDLINE database through January 30, 2009 identified no additional published studies that alter these conclusions.

References

1. BlueCross and BlueShield Association Medical Policy Reference Manual, Policy No. 2.01.70
2. National Library of Medicine. "ClinicalTrials.gov." November 2005. National Institutes of Health.  www.clinicaltrials.gov/ct/gui/show/NCT00252941?order=1  (Verified 1/30/09)
3. www.fda.gov/cdrh/pdf6/p060010b.pdf  (Verified 1/30/09)
4. Shore ND, Dineen MK, Saslawsky MJ et al. A temporary intraurethral prostatic stent relieves prostatic obstruction following transurethral microwave thermotherapy. J Urol 2007;177(3):1040-6
5. Dineen MK, Shore ND, Lumerman JH, et al. Use of a temporary prostatic stent after transurethral microwave thermotherapy reduced voiding symptoms and bother without exacerbating irritative symptoms. Urology. 2008;71(5):873-7
6. Corica AP, Larson BT, Sagaz AG et al. A novel temporary prostatic stent for the relief of prostatic urethral obstruction. BJU Int 2004;93:346-48
7. van Dijk MM, Mochtar CA, Wijkstra J, et al.  Hourglass-shaped nitinol prostatic stent in treatment of patients with lower urinary tract symptoms due to bladder outlet obstruction. Urology 2005;66(4):845-9
8. van Dijk MM, Mochtar CA, Wijkstra J, et al. The bell-shaped nitinol prostatic stent in the treatment of lower urinary tract symptoms: experience in 108 patients. Eur Urol 2006;49(2):353-9
9. Kijvikai K, van Dijk MM, Pes PL, et al. Clinical utility of “blind placement” prostatic stent in patients with benign prostatic obstruction: a prospective study. Urology 2006;68(5):1025-30
10. Grimsley SJ, Khan MH, Lennox E et al. Experience with the spanner prostatic stent in patients unfit for surgery: an observational study. J Endourol 2007;21(9):1093-6

Cross References

None

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