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CONTACT INFORMATION |
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J. Francois Eid, M.D.
50 East 69th Street
New York, NY 10021 |
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Ph: 212-535-6690 |
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Fax: 212-535-7025 |
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Advancement and Innovation in Penile Prosthesis Technology |
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In late 2000, Parylene Micro Coating was introduced as a feature to enhance the American Medical Systems 700 Series cylinder durability and subsequent longevity. Parylene coating is applied via a vapor deposition process to non-tissue-contacting surfaces. It increases lubricity to the silicone surface, hence reducing friction and wear. The new Parylene coating, a micro-thin (60 millionths of an inch) layer, has been demonstrated in bench testing to add millions of fold and tube wear stress cycles before detectable wear is noted on the silicone surface.
AMS introduced the very first permanent antibiotic eluting implant (InhibiZone) in May 2001. InhibiZone is a formulation of Minocycline Hydrochloride and Rifampin, which is impregnated onto the outer surfaces of the device resulting in a marbled yellow-orange trace or modelled effect. Depending on the size of the penile prosthesis selected, devices are manufactured with a quantifiable amount of minocycline and rifampin. Antibiotics impregnated into the device surface elute from the silicone matrix when exposed to a warm, moist environment, resulting in a localized antibiotic regimen. Concentrations represent less than a common oral or IV dose. The cylinders, reservoir, pump and tubing are all completely treated with the drug eluting technology.
Minocycline and rifampin have been safely used as a surface treatment in indwelling venous and urinary catheters. The scientific platform was transferred to the IPP technology to focus on a proven method to provide broad-spectrum inhibitory activity against gram-positive, gram-negative bacteria (1). Literature shows the combination of minocycline and rifampin to act synergistically to prevent colonization of bacteria and be particularly effective against staphylococcus, the most common cause of IPP infection (2).
The majority of the InhibiZone antibiotic surface treatment elutes from the IPP within the initial 2-3 days post-implant, with the remainder of the drug eluting over the next 2-3 weeks. Thus, the effects of InhibiZone primarily reduce early infections. Expectations of a rifampin and minocycline combination should show a reduction in staphylococcal-based infections, the most common cause (about 70%) of IPP infections. Parylene micro coating to increase cylinder durability is also incorporated into the InhibiZone cylinders.
In January 2000 the Mentor Lock-out™ valve reservoir was introduced to the market. The Lockout valve is designed to prevent auto-inflation of the penile cylinders. The Lockout valve has been demonstrated in bench testing to prevent auto-inflation of cylinders despite extensive force on the reservoir or elevated pressure within the reservoir. In preliminary clinical evaluation, the Lock-out valve has significantly diminished the prevalence and severity of auto-inflation.
In May 2002, Mentor Corporation introduced a more anatomical distal cylinder tip (which was introduced with the Narrow-base cylinders in May of 1996) to the standard Alpha I cylinders. The anatomically shaped distal tip is designed to provide for a better fit and a natural aesthetic result. In addition, the smooth, soft distal tip of the Alpha I is seamlessly integrated into the cylinder bladder.
The Narrow-base cylinders prosthesis (introduced in May 1996) is the only pre-connected narrow inflatable device available. Implant base diameter is 3.7mm narrower (with rear tip extenders) than the regular Alpha I implant. The cylinder bladder diameter has also been reduced by 2mm, resulting in an ideal design for fibrotic corpora, re-operations and narrow anatomy. In addition the cylinder base/tubing angle is reduced from 45 degrees to 22.5 degrees, which allows for easier placement into the proximal corpora. The dilation required for placement of this device is only to 10mm. This allows for easier surgeries and decreases the risk of perforation of the tunica albuginea. Also the narrow-base cylinder design results in less pronounced folds while in the flaccid state. Finally, the narrow-base cylinder expands to 18mm girth when inflated (same as AMS 700 series).
The Mentor Titan™ Hydrophilic Coating prosthesis was introduced in the US in August 2002. This coating is covalently bonded and designed for long-term attachment to the device. This hydrophilic coating is designed to help inhibit bacterial adherence. This technology when used to coat central venous catheter and hydrocephalus shunts was effective against staphhylococcus(3,4). Animal studies demonstrated sustained inhibition against Staph epidermidis up to three days following implantation (5). This hydrophilic surface allows physicians to maintain their current antibiotic device preparation. When soaked in an antibiotic solution prior to implantation, antibiotic which will coat the device will then be eluted over a time period. In addition the surface of the cylinders become lubricious, which makes it easier to implant the device.
AMS introduced the Tactile pump for the 700 series implant in July of 2004. In addition of being able to transfer a slightly larger volume of fluid with each squeeze, the pump came with a modified exterior surface for easier inflation. The deflation part of the pump was also increased in size and sharper edges were added to permit easier localization of the deflation valve and permit better deflation. In January 2006 AMS introduced the first pump with a one-touch button called the AMS 700MS for “Momentary Squeeze” designed for easier deflation. These features allowed the patient to first press the button, and then squeeze the cylinders to obtain full deflation. Holding the deflation valve while squeezing the cylinders was no longer necessary. In addition, the pump had a smaller body, which increased patient comfort and a lockout valve to resist auto inflation. Finally palpable ridges were added to the pump to permit easier inflation.
In July of 2008, Coloplast (previously Mentor) received approval for the “One touch release” pump that also allowed the patient to squeeze one time only and release to obtain deflation. This is an important development for the Titan model because the deflation was always difficult for patients implanted with the previous model.
1. Raad I, Darouiche R, Dupuis J, Abi-Said D, Gabrielli A, Hachem R,Wall M, Harris R, Jones J, Buzaid A, Robertson C, Shenaq S, Curling P, Burke T, Ericsson C. Central venous catheters coated with minocycline and rifampin for the prevention of catheter-related colonization and bloodstream infections: a randomized, double-blind trial. Ann Internal Med 1997 v. 127 p. 267-274.
2. Carson CC. Management of prosthesis infections in urologic surgery. Urologic Clinics of North America Nov. 1999 v. 26(4)
p. 829-839.
3. Jansen B. Jansen s, Peters G, Pulvere G. In vitro efficacy of a central venous catheter (‘hydrocath’) loaded with teicoplanin to prevent bacterial colonization. J Hosp Infect 1992; 22:93-107.
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