title: Longitudinal and Horizontal Load Testing of Inflatable Penile Implant Cylinders of Two Manufacturers: An Ex Vivo Demonstration of Inflated Rigidity.
abstract: BACKGROUND
  Since the inception of the inflatable penile prosthesis, a new era has been ushered in for the management of erectile dysfunction. Despite multiple innovations to improve function and reliability, there are no current data comparing the biomechanical properties of these devices.
  
  
  OBJECTIVE
  To compare the resistance of the Coloplast Titan (Minneapolis, MN, USA) with that of the AMS 700 LGX (Minnetonka, MN, USA) penile prosthesis cylinders to longitudinal (penetration) and horizontal (gravity) forces.
  
  
  METHODS
  We compared two cylinder sizes from each company: the Coloplast Titan (18 and 22 cm) and the AMS 700 LGX (18 and 21 cm). To evaluate axial rigidity, which simulates forces during penetration, we performed a longitudinal load compression test to determine the load required to cause the cylinder to kink. To test horizontal rigidity, which simulates the horizontal forces exerted by gravity, we performed a modified cantilever test and measured the degrees of bend for each device. All devices were tested at 10, 15, and 20 PSI to simulate in vivo pressures.
  
  
  METHODS
  The main outcome measurement for the longitudinal load test (penetration) was the force required for the inflated cylinder to bend, thereby affecting its rigidity. The main outcome for the horizontal rigidity test (gravity) was the angle of displacement, in which a smaller angle represents a more horizontally rigid device.
  
  
  RESULTS
  Longitudinal column testing (penetration) demonstrated that less force was required for the AMS device to kink compared with the Coloplast implant across all three fill pressures tested. The Coloplast Titan also had a smaller angle of displacement at the modified cantilever test (gravity) compared with the AMS implant across all fill pressures.
  
  
  CONCLUSIONS
  The Coloplast Titan demonstrated greater resistance to longitudinal (penetration) and horizontal (gravity) forces in this study. The AMS device was very sensitive to fill pressures. In contrast, the Coloplast Titan's ability to resist these forces was less dependent on the device fill pressure.
authors: Department of Urology, Baylor College of Medicine, Houston, TX, USA; Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX.
authors: Jason M
authors: JM
authors: Scovell
authors: Materials Science and Nano-Engineering Department, Rice University, Houston, TX, USA.
authors: Liehui
authors: L
authors: Ge
authors: Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX; Escuela de Ingenieria y Cincias, Tecnologico de Monterrey, Monterrey, Mexico.
authors: Enrique V
authors: EV
authors: Barrera
authors: Institute for Urologic Excellence, Indio, CA, USA.
authors: Steven K
authors: SK
authors: Wilson
authors: Department of Urology, University of South Florida, Tampa, FL, USA.
authors: Rafael E
authors: RE
authors: Carrion
authors: Advanced Urology, Atlanta, GA, USA. Electronic address: tariq7@gmail.com.
authors: Tariq S
authors: TS
authors: Hakky
mesh_terms: D007172:Erectile Dysfunction / Q000628:therapy*; D006801:Humans; D008297:Male; D015917:Penile Prosthesis / Q000592:standards*; D011312:Pressure; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015203:Reproducibility of Results
keywords: Erectile Dysfunction; Material Properties; Prosthesis