Fig. 10.1
The inFlow Intraurethral device in proper position in this drawing cross-sectional area of a woman’s pelvis
The inFlow device with activator is indicated for use “in female patients 18 years of age or older who have incomplete bladder emptying due to impaired detrusor contractility of neurologic origin, and who are capable of operating it in accordance with instructions or who have trained caregivers. The device must be replaced every 29 days (or less)” (FDA 2014).
The FDA granted the approval based on non-clinical testing and a clinical trial that enrolled 273 women with impaired detrusor contractility using clean intermittent catheterization. Over half of the women stopped using the device as a result of discomfort and leakage of urine. The trial showed that 98 % of the 115 women that continued to use the inFlow device had comparable post-void residual urine volume with those who used the intermittent catheterization.
Adverse events associated with the device included asymptomatic bacteriuria, urinary tract infection, bladder inflammation, genital and urinary pain, blood in the urine (hematuria), urinary leakage around the device, urinary frequency/urgency, bladder spasms, and vulvar, vaginal, and urethral disorders. It is noteworthy that urinary tract infection appeared to occur at a lower rate with the inFlow device as compared to clean intermittent catheterization. Among patients treated with the inFlow device, infection was stable and managed with antibiotics.
The inFlow has been sold outside the USA for a decade, mostly in Germany and Australia. Approximately 15,000 devices have been sold to date, amounting to over 1,000 women and years of use based on typical device use of 1 month each. No serious adverse events have been reported. In Germany, the inFlow is available and is reimbursed by the country’s national health system.
Underactive Bladder, Atonic Bladder
Atonic bladder is a medical condition where patients are unable to spontaneously urinate due to insufficient detrusor muscle contraction. The inFlow device was developed to be an alternative to urinary catheters which are among the most commonly used medical devices. However, catheterization is associated with low quality of life, encrustation, stone formation, and recurrent urinary tract infections (UTIs).
The present standard of care for UAB and atonic bladder is clean intermittent catheterization (CIC). If a woman cannot or will not use CIC, then she is likely to end up with a urethral or suprapubic catheter and urine drainage bag. The inFlow prosthetic device compensates for the inability of women with atonic bladder to generate bladder pressure by providing near complete evacuation of urine on demand. By allowing almost normal use of a toilet, the inFlow eliminates the need to catheterize multiple times daily and eliminates tubes/drainage bags, improving its users’ self-image as well as their hygiene (Table 10.1).
Table 10.1
Bladder drainage options inFlow vs. catheterization
Indwelling | Intermittent catheterization | inFlow | |
|---|---|---|---|
Allows bladder cycling | ✓ | ✓ | |
Allows use of toilet | ✓ | ||
Easy to operate | ✓ | ✓ | |
Effectively empties bladder | ✓ | ✓ | |
Minimal UTI rate | ✓ | ✓ | |
Number of insertions/month | 1 | From 120 [×4/day] up to 240 [×8/day] | 1 |
Design
The inFlow device has four components: a sterilized, single-use urethral insert component with silicone shaft, fins, and flange; an introducer; an activator; and a sizing component. The device draws urine out to empty the bladder and blocks urine flow when continence is desired. A physician sizes the patient for an inFlow device and performs the initial insertion. After training, device insertion and removal can be performed by the patient or a caregiver. Each inserted component must be replaced at least once every 29 days.
To void, the user sits on a toilet, holds a remote control over the lower pelvic area, and presses a button. This magnetically activates the miniature internal pump, which drains the bladder at a normal flow rate. When the button is released, the valve is engaged, blocking further urine flow.
How the inFlow Works
The inFlow is a 3–7 cm long device in a silicone housing (shown on top with its disposable introducer and below after deployment). Nine sizes are available in order to account for variations in urethral length using a disposable introducer (Fig. 10.2).
