Morphological aspects of tympanic bulla after lateral osteotomy in cats.

PURPOSE To evaluate tympanic bulla healing after experimental lateral osteotomy in cats. METHODS Twenty adult cats were submitted to unilateral lateral bulla osteotomy and divided into two groups: cats of B1 group (n=10) were euthanized at 8 weeks and cats of B2 group (n=10), at 16 weeks postoperative. RESULTS Oblique lateral radiographs taken immediately postoperative showed interruption in the contour of the external acoustic meatus of the operated bullae in all cats of both groups (McNemar test: p=0.0010*). This feature was still observed in the radiographs taken after 8 and 16 weeks postoperative (McNemar test: B1 p=0.0020*; B2 p=0.0312*). Macroscopic examination showed that the operated bullae were similar to the normal ones, with preservation of the tympanic cavity. Connective tissue at the osteotomy site was significantly found in the operated bullae in both groups (McNemar test: B1 p=0.0020*; B2 p=0.0010*). The length of connective tissue at the osteotomy site was measured by histomorphometry. There was no statistically significant difference between the values of B1 group and B2 group (Mann-Whitney test: p=0.0524). CONCLUSIONS Experimental lateral osteotomy did not alter significantly the tympanic bulla conformation and complete regeneration of the tympanic bulla frequently did not occur before 16 weeks of postoperative period.