title: A Novel Thermal-activated Shape Memory Penile Prosthesis: Comparative Mechanical Testing.
abstract: OBJECTIVE
  To compare a novel nickel-titanium (Ni-Ti) shape memory alloy (SMA) penile prosthesis of our own design with commercially available prostheses using a format similar to mechanical testing done at major penile prosthesis manufacturers. We evaluated the mechanical parameters of commercially available penile prostheses and used this information to guide the development of the Ni-Ti-based physiological penile prosthesis that expands and becomes erect with a small amount of heat applied.
  
  
  METHODS
  A penile prosthesis consisting of an exoskeleton of temperature-tuned Nitinol was designed and prototyped. Mechanical testing was performed in a model of penile buckling, penile lateral deviation, and original penile shape recovery commonly used by penile prosthesis manufacturers for testing.
  
  
  RESULTS
  Our SMA penile prosthesis demonstrated useful mechanical characteristics, including rigidity to buckling when activated similar to an inflatable penile prosthesis (2.62 kgf SMA vs 1.42 kgf inflatable penile prosthesis vs 6.45 kgf for a malleable prosthesis). The Ni-Ti also became more pliable when deactivated within acceptable mechanical ranges of existing devices. It could be repeatedly cycled and generate a restorative force to become erect.
  
  
  CONCLUSIONS
  An SMA-based penile prosthesis represents a promising new technology in the treatment of erectile dysfunction. We demonstrated that an Ni-Ti-based prosthesis can produce the mechanical forces necessary for producing a simulated erection without the need for a pump or reservoir, comparable with existing prostheses.
authors.affiliation: Department of Urology, University of Wisconsin-Madison, Madison, WI. Electronic address: Leb@urology.wisc.edu.
authors.forename: Brian
authors.initials: B
authors.lastname: Le
authors.affiliation: Department of Urology, Southern Illinois University, Springfield, IL.
authors.forename: Kevin
authors.initials: K
authors.lastname: McVary
authors.affiliation: Feinberg School of Medicine, Northwestern University, Chicago, IL.
authors.forename: Kevin
authors.initials: K
authors.lastname: McKenna
authors.affiliation: Department of Urology, Southern Illinois University, Springfield, IL; Feinberg School of Medicine, Northwestern University, Chicago, IL.
authors.forename: Alberto
authors.initials: A
authors.lastname: Colombo
mesh_terms: D007172:Erectile Dysfunction / Q000601:surgery; D006245:Hardness Tests; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods*; D009532:Nickel; D015917:Penile Prosthesis; D011474:Prosthesis Design; D013696:Temperature; D013718:Tensile Strength; D014025:Titanium
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium