Comparison of Mechanical Reliability of Original and Enhanced Mentor Alpha I Penile Prosthesis

Purpose: 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.

Materials And Methods: 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.

Results: 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.

Conclusions: Our results strongly support the premise that mechanical reliability is superior with the enhanced compared to the original model.