Comparison of mechanical reliability of original and enhanced Mentor Alpha I penile prosthesis.

Abstract

We report the results of a prospective study of 1,381 Mentor Alpha I penile prostheses implanted to treat impotence, and compare original and enhanced penile prosthesis mechanical reliability. The study consisted of 410 original models manufactured before November 1992 and 971 enhanced models manufactured since December 1992. Implants were further stratified as first time (virgin) or replacements of a previous implant. Mechanical failure-free survival rates for the original prosthetic and enhanced models were compared. The 5-year survival rate increased from 75.3% for the original to 92.6% for the enhanced model overall (log rank p<0.0001), and from 75.3 to 93.6%, respectively, for the virgin implants only (log rank p<0.0001). The estimated failure rate of approximately 5.6% for the original model was fairly consistent during followup, while the significantly lower failure rate of 1.3% for the enhanced model was not. The failure rate of the enhanced model implants was about 0.8% per year during the first 3.5 years and increased to approximately 3.1% per year thereafter. Our results strongly support the premise that mechanical reliability is superior with the enhanced compared to the original model.