Published online by Cambridge University Press: 29 June 2007
The present study evaluates histological characteristics of the soft tissue response to long-term implantation of Apaceram™ discs composed of dense hydroxyapatite in rats. Discs were implanted into the subcutaneous tissue of 76 rats for six to 20 months. Decalcified histological sections stained with haematoxylin and eosin (H & E) and Mallory's azan were examined. Different cell types surrounding implants were counted. The greatest proportion of macrophages was found at six months (13.5 per cent). This proportion gradually decreased to four per cent at 20 months. Small numbers of lymphocytes and foreign body giant cells were observed in every group, but neither neutrophils nor osteogenesis were observed in any specimens. Results of the present study and previous related studies indicate that despite reappearance of a small number of macrophages six months after implantation, Apaceram™ is useful for reconstructive surgery.
This paper was presented 17–19 October 1996 at the conference of the Otological Society of Japan in Tokyo, organized by the Department of Otolaryngology, School of Medicine, Keio University, Tokyo 160, Japan.