I have been fortunate to cross paths with several trailblazers of the surgical management of male urinary incontinence. Dr Brantley Scott and Dr Timothy Boone from the Baylor College of Medicine, and later in my career, Dr J. J. Kaufman and Dr Shlomo Raz from University of California Los Angeles. They have all, along with others, influenced and inspired my interest in evaluating, managing, and investigating surgical treatment options for male urinary incontinence.

Historical Perspectives

The evolution of treatment for male sphincteric urinary incontinence may be traced back to the eighteenth century. Two main schools of thought simultaneously evolved. One school of thought advocated the construction of fixed urethral compression devices to enable urethral obstruction by fixed resistance. The other school of thought advocated creation of dynamic urethral compression in which outlet resistance is not fixed but may be decreased when voiding is desired or elevated between micturitions. Therapeutic fixed and dynamic urethral compression interventions may be further divided into external or internal compressive devices or procedures. Dynamic compressive devices applied externally were developed much later, such as the first artificial urinary sphincter (AUS), described by Foley in 1947, and the Vincent apparatus, described in 1960. The modern era of fixed urethral compression began in 1961 with Berry. Acrylic prostheses impregnated with bismuth to allow radiographic visualization were produced in various shapes and sizes and used to compress the urethra against the urogenital diaphragm. In 1968 the University of California Los Angeles group under the direction of Dr J. J. Kaufman began to use cavernous crural crossover to compress the bulbous urethra (Kaufman procedures). With the advent of the fluid-filled AUS pioneered by Dr Brantley Scott in 1973, interest in passive urethral compression disappeared in favor of the implantation of an inflatable circumferential prosthetic sphincter. Recently, the male synthetic prolene passive compression sling has made a comeback with variable safety and efficacy results.

I am in favor of the circumferential dynamic compression approach for artificial sphincteric prosthetic surgery. I believe it is more physiologic and reliable. Unfortunately, current pitfalls in the Brantley Scott AUS (now called the AMS 800) have not been addressed since 1981, dating the last modifications of the AMS 800 (Figure 1). Cuff atrophy, erosion, infection, device trauma from urethral catheterization, fluid leak, tubing degradation, and trauma remain current issues with the gold standard AMS 800.

Figure 1. The artificial urinary sphincter.

Novel Approaches in AUS Design Using Bluetooth Technology

To circumvent these technical difficulties, we have developed 2 devices based on Bluetooth technology. As chief surgeon and lead investigator of the companies below, along with Mr Peter Sayet, we have made the following patented contributions to the science and art of male urinary incontinence.

Precision Medical Devices had previously developed a new AUS. The Bluetooth Flow Control Device (PSS-FCD) had undergone 6 previous prototypes before establishing this current model (the new Smart Bionic Interactive [hybrid] Sphincter/Sling [SBISS] device).

The final FCD model was composed of 3 elements: (1) a control/battery pack (CBP), (2) a valve assembly with separate anvil cap piece, and (3) a remote master control module (Figure 2).

Figure 2. The flow control device.

The CBP consisted of electronic and drive components. A printed circuit board, stepper motor, and a lithium cell array are contained in the fully hermetically sealed waterproof titanium casing.

The valve assembly consisted of a cable link, a plunger, and 2 shell halves. The cable link connects the cuff and plunger to the CBP. The CBP opens and closes the plunger via the drive assembly and has the ability to adjust the magnitude of closure force with 10 different settings based on commands made to the CBP using the Bluetooth telemetry system. Closure pressure of the FCD was determined from the device clamp force measured using a strain gauge load cell and amplifier in a benchtop test stand.

The typical closure pressure of a healthy human urethra ranges from 75 to 100 cm H₂O. The PSS-FCD has a clamp pad with 2 flexible silicone ridges of 4 mm in width resulting in a total clamping area at a urethra closure of 75 mm². The FCD produced an average clamp force of 3.67 N resulting in a closure pressure of 0.057 N/mm², or about 584 cm H₂O at the PSS-FCD clamp stroke setting of 08. The clamp force can be adjusted by changing the clamp stroke within the range of 04 to 10 during or after implant surgery as required to occlude fluid flow.

Using animal studies, we have demonstrated biologic tissue compatibility without urethral trauma or erosion in a canine model during survival experiments lasting more than 1 year. We demonstrated the easy feasibility of performing full FCD replacement on 4 animals without complication.

The more recent update of the FCD is the Integral Medical Devices Inc SBISS (Figure 3)

Figure 3. The Smart Bionic Interactive (hybrid) Sphincter/Sling.

The main difference between the 2 aforementioned Bluetooth devices, the FCD and SBISS, is the avoidance of a hydraulic (fluid-filed) device. Furthermore, the drive mechanism and the functional component compresses the urethra at a multitude of pressure ranges in seconds. The devices utilize an electromechanical wire drive instead of a hydraulic scrotal pump and a fluid-filled cuff and reservoir. Unfortunately, the AMS 800 allows only 3 ranges of urethral pressure (51-60 cm H₂O, 61-70 cm H₂O, 71-80 cm H₂O).

The telemetric systems allow a better degree of adjustability with the electromechanical wire drive and valve system without the need for manual dexterity.

The previous FCD and the current SBISS systems have been designed to minimize cuff atrophy and ischemic damage to the urethra during its compression, which is of paramount importance in preserving the urethral tissue integrity. Another unique feature differentiating the SBISS from the FCD device is the use of a sling-like component and an already-attached flexible anvil belt added to assist in the preservation of the urethra over long durations of compression. We postulate that the newest prototype model SBISS holds promise to become more suitable for long-term use while maintaining superior closing power and leak rate than the current AMS 800 model. We anticipate ease of implant, a quicker learning curve, less trauma to the AUS, less infection, and more capability for self-adjustment by the patient to be the key advantages of these modern devices.

The combination of all these new design elements incorporated into the SBISS should set a new standard for safety and efficacy in the use of a compression device to optimally treat sphincteric deficiency in male urinary incontinence. Further animal studies will be ongoing to test the safety and efficacy of these novel AUS devices.

We’re looking forward to this journey.