First Report

U.S. Patient and Clinician Experiences With the inFlow™ Urinary Prosthesis for Permanent Urinary Retention in Women

Leanne Schimke, MSN, FNP-C, CRNP, CUNP; Kevin M. Connolly


Urol Nurs. 2020;40(2):61-73. 

In This Article

The inFlow Urinary Prosthesis

In October 2014, the FDA approved the inFlow Intraurethral Valve-Pump and Activator (collectively, the "inFlow Urinary Prosthesis") for the treatment of PUR. The FDA's review is available as De Novo Summary for DEN130044 (FDA Center for Devices and Radiological Health, 2014). In its analysis, the FDA described the pivotal trial (N = 273) that compared the inFlow to CIC, the current standard of care, and reviewed six non-comparative clinical studies (Chen et al., 2005; Lynch et al., 2003; Madjar et al., 1999, 2000; Mazouni et al., 2004; Nativ et al., 1997; Schurch et al., 1999).

Key findings from the FDA's review include:

  • Infection. In a scientific first, the UTI rate for the inFlow, although an indwelling device, appeared to be lower than that for CICs. When pivotal subjects were crossed over from CIC to the inFlow, UTI rates quickly declined and continued to decline the longer the inFlow was used.

  • Encrustation. No inFlow device failed due to encrustation.

  • Quality of Life. Quality of life improved significantly with the inFlow compared with CIC.

In addition, the FDA reported that the inFlow emptied the bladder as well as CIC and that multiple cystoscopy examinations demonstrated the inFlow had no deleterious effects on the urethral or bladder mucosa.

These findings and functional benefits, such as the ability to use a toilet or commode in a near-normal manner, may be reasonably interpreted as demonstrating that the inFlow represents the current state-of-the-art in bladder drainage. However, inFlow use in the United States to date has been restricted due to a lack of Medicare coverage, not an uncommon problem for innovative medical devices. The inFlow has a 19-year history as a CE-marked device, with an estimated 1,200 women-years of clinical experience, mostly in Germany and Australia, where national health systems provide coverage. As required by the International Organization of Standards (ISO), the inFlow's complaint files were audited annually by its notified body, and there were no recalls or reports of serious adverse events (unpublished regulatory data).

As the inFlow incorporates a unique approach to bladder drainage – it normalizes voiding vs. passively draining urine via a tube – clinicians will need to fully understand its operation to appropriately select and subsequently support women in using the device. Therefore, the next section describes the inFlow in some detail.

The inFlow's two components include a miniature valve-pump mechanism in a silicone housing that is inserted in the urethra (Figure 2) and a handheld remote control (the Activator) (Figure 3). Pressing the button on the Activator engages the device pump, which draws out urine at a near-normal flow rate. Release of the button automatically engages the device valve, which then blocks the flow of urine. As a prosthetic device, the inFlow is intended to normalize voiding to the greatest extent possible. It compensates for the inability to spontaneously urinate by providing, on demand, a forceful and virtually complete evacuation of urine, which allows most women to use a toilet in an almost normal manner (Figure 4).

Figure 2.

The inFlow Device Shown with Its Disposable Introducer (Top) and After Deployment (Bottom)
Source: © 2015–2020. Vesiflo, Inc. Reprinted with permission.

Figure 3.

The Activator Remote Control Shown in Its Base for Storage and Recharging
Source: © 2015–2020. Vesiflo, Inc. Reprinted with permission.

Figure 4.

Using the inFlow device to void allows most women to use a toilet or commode in a near-normal manner.
Source: © 2015–2020. Vesiflo, Inc. Reprinted with permission.

Prior to patient use, an initial evaluation by the treating urology provider is required to assess the individual's suitability for the device. Potential candidates for the inFlow device can be identified via urodynamic testing results, multiple bladder volume measurements that show a clinically significant post-void residual, or a history of urinary catheterization. The inFlow, designed for use by women, is a treatment option available for those who rely on CIC or indwelling urinary catheterization. Per FDA instructions for use, the only two contraindications to the inFlow are patients with an active urinary tract infection, and patients who are allergic to or otherwise cannot take oral antibiotics.

Patient sizing and initial device insertion are performed by a urology provider. Device size is determined using the inFlow Sizing Device, which measures urethral length. Nine device sizes are available, from 3 cm to 7 cm in 0.5 cm increments. The device is packaged with a disposable introducer, and pushing its plunger deploys the device. This causes flexible silicone fins on the device to expand, providing bladder neck fixation (Figure 5a). A silicone tab anchors the device at the meatus (Figure 5b).

Figure 5.

inFlow Device Deployment (A), inFlow Device in vivo (B), and inFlow Device Removal (C)
Source: © 2015–2020. Vesiflo, Inc. Reprinted with permission.

The inFlow device should be removed and replaced every 29 days, but the device can be easily and safely removed at any time by simply grasping its tab and pulling it straight out (Figure 5c). The insertion of replacement devices is typically performed in office by either an advanced practice provider or nurse; however, it can also be done by a trained caregiver or spouse at home.

The patient must keep the Activator available to them at all times, as well as an alternate means of bladder drainage, in case the device fails. Women must urinate every three to four hours during the day, and they should contact their provider if they see blood in the urine, sense dysuria, suspect the device is not functioning properly, or require an MRI (or radiation treatment, per FDA-approved instructions). The device contains a metal magnet and therefore needs to be removed prior to a, MRI. The inFlow can be easily removed and a new one reinserted after the MRI. If a woman is undergoing pelvic radiation, it is recommended the device be discontinued until radiation therapy is completed.

There are a number of women who cannot tolerate the inFlow device, possibly due to urethral hypersensitivity. These women self-identify after the initial device insertion, as they express an inability to accommodate to its presence. Prophylactic use of anticholinergics is a well-established practice for new inFlow users and is recommended in the FDA-approved instructions for use to improve tolerance of the device. -