Int. Adv. Otol. 2010; 6(3): 299-306

Alpha-tricalcium phosphate bone cement in the surgical treatment of open mastoid cavity.
Robinson Koji Tsuji, Vanda Jorgett, Ricardo Ferreira Bento, Rubens de Brito Neto. Clinical Hospital of the Medical University of São Paulo, Brazil

Hypothesis: This study aimed to evaluate the biocompatibility of alpha-tricalcium phosphate bone cement in the obliteration of the mastoid cavity in guinea pigs.
Background: Treatment with open cavity mastoidectomy can present poor functional results in chronic otitis media with cholesteatoma, especially if the cavity is quite large. Partial or total obliteration of the cavity can correct these problems. Alpha-tricalcium phosphate bone cement has physicochemical characteristics that suggest its potential in mastoid cavity obliteration.

Methods: Twenty guinea pigs were studied. All animals underwent surgery involving manipulation of the dorsal tympanic bulla. In the study group animals (n = 10), mastoid cavity obliteration was conducted with alpha-tricalcium phosphate bone cement. In the control group animals (n = 10), the cavity was left unfilled.
On postoperative day 60, the animals were sacrificed and studied for signs of rejection of the material and other complications. Temporal bones were removed for histopathological study, in which the type and degree of inflammatory response, as well as the degree of ossification, were analyzed.

Results: The mortality rate was the same in both groups. Deaths were attributed to anesthetic complications in the initial postoperative period. In the animals that survived, there were no complications, and there was good healing of the incision in both groups. There were no clinical signs of rejection of the material, and the histopathological analysis of the cement group revealed no signs of foreign body reaction (inflammatory response).

Conclusion: Alpha-tricalcium phosphate bone cement is biocompatible in the mastoid cavity of guinea pigs