title: Hardness evaluation of penile prostheses.
abstract: OBJECTIVE
  This work investigates the hardness and buckling force of penile prostheses to further understand the rigidity of penile prostheses before and after implantation.
  
  
  METHODS
  Evaluated herein are four prosthetic samples (three inflatable, one semi-rigid), five real prostheses (one inflatable, four semi-rigid), and one prosthesis after implantation. The hardness is measured with a Shore Durimeter by pressing the tester's indentor to the surface of the specimen. A volunteer with inflatable prosthesis implantation is evaluated with respect to penile hardness versus various numbers of pumping. The buckling force of the prosthesis is also determined by a push-pull gauge and a specially designed sampling table.
  
  
  RESULTS
  Results in this study demonstrate that although the inflatable prosthesis could only be pumped to a certain amount of hardness, hardness and buckling force correlate well with each other. After reaching the hardness limit, prostheses can even be pumped a further few times. However, continuous pumping only puts more tension on the prosthetic material without increasing hardness and could induce mechanical failure of the prosthesis. Results also indicate that the buckling force decreases with increasing length of the semirigid prostheses, and increases when the prosthesis has a larger diameter.
  
  
  CONCLUSIONS
  This mechanical measurement of rigidity in penile prostheses could provide more information to clinicians about the penile prosthesis before surgical implantation, and to patients about prosthesis usage after implantation.
authors.affiliation: Division of Experimental Surgery, Department of Surgery, Taipei Veterans General Hospital, and Department of Urology, School of Medicine, National Yang-Ming University, Taipei, Taiwan. wangsj@vghtpe.gov.tw
authors.forename: Shyh-Jen
authors.initials: SJ
authors.lastname: Wang
authors.forename: Kuang-Kuo
authors.initials: KK
authors.lastname: Chen
authors.forename: Alex Tong-Long
authors.initials: AT
authors.lastname: Lin
authors.forename: Shuenn-Tsong
authors.initials: ST
authors.lastname: Young
authors.forename: Luke S
authors.initials: LS
authors.lastname: Chang
mesh_terms: D006245:Hardness Tests; D006801:Humans; D008297:Male; D008422:Materials Testing; D015917:Penile Prosthesis; D013718:Tensile Strength; D016474:Weight-Bearing