[Cutaneous responses to an injectable collagen implant (zyderm). Clinical, histological and ultrastructural correlations after intradermal tests]. / Réponses cutanées à l'implant de collagéne injectable (zyderm). Corrélations cliniques, histologiques et ultrastructurales aprés tests intradermiques.

A test implant of Zyderm collagen was carried out on 250 patients using the volar forearm site. The behaviour of the implant in the host tissue was followed-up in 6 cases by both direct and electron microscopy. There were 14 positive reactions. Biopsy was carried out in 3 cases, all of which exhibited severe reactions; foreign body granulomata were found in 2 of these, perivascular lymphocytic infiltration in the third. All 3 had a follow-up for 3 months and the biopsy sites healed normally. Trial implants are always advisable with collagen material. In order to avoid the possibility of such delayed hypersensitivity reactions, the test implant should be investigated at 72 hours and kept under observation for 4 weeks prior to carrying out the full corrective procedure. In two cases, reactive adverse reactions at the collagen implant treatment site were observed in spite of negative reaction at the test site. Nevertheless evidence suggests that Zyderm injectable collagen is a suitable material, leading to good cosmetic results; it carries minimal risk and is well tolerated even after a long period of time.