Mechanical reliability of AMS 700 CX improved by parylene coating.

INTRODUCTION

Parylene coating was added to the silicone layers of the American Medical Systems (AMS) 700 controlled expansion (CX) penile prosthesis cylinders in January 2001. The coating was placed on non-tissue contacting silicone surfaces to increase lubricity, reduce friction, and silicone wear

AIM

We compared mechanical reliability of the original and Parylene-enhanced AMS 700 CX in a large single surgical group series.

METHODS

Seven hundred seventy-five consecutive patients receiving the AMS 700CX prosthesis (596 first time [virgin] and 179 revisions) were followed for 3 years. Four hundred fourteen received the non-coated model and 361 received the Parylene-coated device. Revision-free survival was estimated using the Kaplan-Meier product limit method and compared using the log-rank test.

MAIN OUTCOME MEASURES

We calculated overall survival from revision for any reason and survival from mechanical problems such as fluid leakage, cylinder, connector or tubing breakage, pump or reservoir defects.

RESULTS

For the entire series (virgin + revised) the 3-year revision free survival for any cause improved from 78.6% for non-coated to 87.4% for the Parylene-coated implants. Freedom from mechanical breakage showed similar improvement from 89.2% for the non-coated to 97.5% for enhanced models.

CONCLUSIONS

This study documents that short-term mechanical reliability and survival from revision for any cause is significantly increased with Parylene-coated AMS 700CX cylinders compared with the earlier AMS 700CX model with non-coated cylinders.