The investigation of the histological and functional effects of hydroxyapatite use in nasal septal surgery in a rabbit model.

ABSTRACT Hasan K. The investigation of the histological and functional effects of hydroxyapatite use in nasal septal surgery in a rabbit model. Abant Izzet Baysal University Medical School, Department of Ear Nose Troat Head and Neck Surgery, Medical Residency Thesis, Bolu, 2014 Aim Hydroxyapatite is a biomaterial used in medical field more than 20 years. It is known to be used in rhinoplasty as augmentation material. But there is scant information about its use in septoplasty. In our study we aimed to investigate histological and functional effects of hydroxyapatite use in nasal septal surgey in a rabbit model. Method Three groups of eight New Zealand white rabbits weighing between 1.8 and 2.8 kg were used. In Group 1, aproxiametly 1x0.5 cm of cartilage was removed from the anterior part of the septal cartilage and this cartilage was placed without any other intervention, in order to constitute the sham group. In Group 2, 1x0.5 cm cartilage was removed from the the anterior part of the septal cartilage and it was replaced with hydroxyapatite plate which is about in the same size. In Group 3, 1x0.5 cm cartilage was removed from the anterior part of the septal cartilage, and it was placed with an hyroxyaatite plate side by side. During the experimental period of 3 months intermitant examinations were performed and the findings were recorded. At the end of experiment, all subjects were sacrified in order to perform macroscopical and histological evaluation. Findings Sings of inflammation were very mild or nonexistent in samples taken from Group 1. In Group 2 and 3 there were more inflammation compared to Group 1. The difference in the severity of inflammation between Group 1 and the other 2 groups was statistically significant. (p = 0.005) Inflamatory findings were more prominent in Group 3 compared to Group 2. However, the difference in the severity of inflammation between Group 3 and Group 2 was not statistically significant. (p = 0.161). Macroscopic examinations revealed that all the hydroxyapatite grafts were rejected in Group 2. In Group 3, in which both hydroxyapatite and cartilage were used, it was found that 5 grafts out of 8 were rejected. There were no statistically significant difference between Group 2 and 3 in terms of grafts material rejection, at the end of first, second, and third months. (p=0.50, p=0.31, p=0.10). Conclusion The data we obtained in our study shows that the use of hydroxyapatite as allograft in rabbit septum is quite difficult. Further animal experiments would be illustrative, especially by using thinner hydroxyapatite plates which have larger porous.