Torps and porps: a transmission and scanning electron microscopic study.

TEM and SEM were used to evaluate the fate of eleven Plasti-pore prostheses left in the human middle ear for periods varying from seven to 34 months. It was evident that Plasti-pore is a relatively inert material based on its clinical performance, absence of gross fibrous tissue reaction from the middle ear, and the unchanged physical characteristics of the prosthesis. Micro-disintegration of the TORPs and PORPs was suggested by the consistent foreign body reaction invading their structure, and the presence of particulate-like matter inside the giant cells. However, micro-disintegration did not affect the physical characteristics of the prosthesis and seem to have little bearing on their clinical performance. The question of the long-term performance of Plasti-pore remains to be answered.