Histologic Serial Changes of Obliterating Materials in the Rat Temporal Dorsal Bullae

1 and Myung-Koo Kang, MD 1 ABSTRACT Background and Objectives:Mastoid obliteration surgery is a modern trend for otitis media either with or without cholestea- toma. The aim of our study is to evaluate histologic changes and effectiveness over time resulting from different obliterating materials and the existence of mucosa in the temporal dorsal bullae in rats. Materials and Method:Rats were divided into two groups. One group had the mucosa removed and was treated with trichloroacetic acid (TCA). The other group with mucosa remaining was untreated. The temporal dorsal bullae of the two groups of rats were obliterated with Mimix ® (hydroxyapatite cement), Regenafil ® (demineralized bone matrix), cartilage chip, and bone chip. Three months and again six months after the implantation, 5 animals in each group were examined. A histological study was performed to evaluate inflammation, new bone formation, and mucocele formation within the bullae. Results:The group that had Mimix ® implanted had a high inflammatory reaction, low implanted material resorption and cyst formation. The group with Regenafil ® implanted had high cyst formation and more cyst formation with the passage of time. The group with bone chip implanted had high new bone formation, but also high cyst formation. The group that had cartilage chip implanted had high new bone formation, low implanted material resorp- tion and low cyst formation. Conclusion:Cartilage chip is the only material that should be used in the air cell with mucosa remaining. Demineralized bone matrix and bone chip should not be used in the air cell with mucosa remaining. Hydroxyapatite cement should not be used due to severe inflammation. (Korean J Otorhinolaryngol-Head Neck Surg 2009;52:220-7)