Intraluminal Device Pressures in 3-Piece Inflatable Penile Prostheses: The “Pathophysiology” of Mechanical Malfunction

Abstract

The role of intraluminal device pressures in the development of mechanical failures in 3-piece inflatable penile prostheses was investigated in a 2-part study. An in vitro study was performed in which mean intraluminal device pressures were recorded in Mentor IPP, Mentor Alpha-1, AMS 700 CX and AMS Ultrex devices. At maximum inflated volumes mean intraluminal device pressures exceeded 600 and 1,000mm.Hg at rest, and 850 and 1,300mm.Hg following external loading in Mentor and AMS products, respectively. The AMS 700 CX was associated with the highest mean intraluminal device pressure, with values approaching 1,400mm.Hg following external loading.A 4-year clinical review at our institution was performed comparing the mechanical malfunctions in 51, 3-piece implants with connectors between the pump and cylinders (AMS 700 CX) to the mechanical malfunctions of 50, 3-piece implants with pre-connected tubing between the pump and cylinders (Mentor Alpha-1). Fluid leaks were identified in 16% of the former and 4% of the latter devices. It is proposed that the high intraluminal device pressures are an important factor in the pathophysiology of the mechanical malfunctions in 3-piece inflatable penile prostheses and that connectors are considered components at risk for pressure-associated fluid leaks. The ideal penile prosthesis should maintain the superior rigidity and cosmetic features of the 3-piece inflatable penile prosthesis. However, this device should be pre-connected and designed to mimic more closely the anatomy of the human penis to achieve functional erections at lower intraluminal device pressure values.