2005 Volume 15 Issue 3 Pages 195-202
The aim of this clinical study is to develop the new treatment for intractable otitis media such as adhesive otitis media, severe cholesteatoma, and so on. Poor development of mastoid cavity and its air cells is often observed in chronic otitis media patients. The functions of the mastoid air cells had not been found for a long time. Recent studies, however, reported that the mastoid air cells had the gas exchange function through their blood capillaries in mucosa covered over the wall of mastoid air cells. This system and the Eustachian tube function keep the middle ear cavity an adequate pressure. Therefore, failure of this system is thought to prevent chronic otitis media from recovery. In this study, we tried to regenerate the pneumatic air cells and their gas exchange function in the patient with chronic otitis media.
Eighteen patients (8 males and 10 females) were randomly selected from chronic otitis media patients with cholesteatom (n=10), cholesteatoma with adhesive otitis media (n=5), and severe chronic otitis media (n=3). Patients ranged in age from 5 to 85 years. All but one patient, with severe chronic otitis media, underwent both stages of the two-staged operation. These patients were divided into two groups. Group I (n=5) was performed the regenerative operation and the usual mastoidectomy. Group II (n=13) was performed the regenerative operation and the mastoidectomy with the mastoid cortex bone plasty. The followup period was from 9 to 12 months after the second-stage of tympanoplasty.
Hydroxyapatite of honeycomb-like structures was made and used as a framework for artificial pneumatic bones. This artificial material with a high macropore ratio of 90 % was mainly composed of calcium phosphate. And its surface was coated with collagen from porcine skin to promote mucosal cells attachment. At the first-stage of tympanoplasty, collagen-coated HA was implanted into the newly opened mastoid cavity and was fixed by fibrin glue in the both groups. After the first operation, recovery of mastoid aeration and regeneration of the pneumatic air cells of the newly opened mastoid cavity were assessed on high resolution CT scan images.
At the second-stage operation, the cortex bone of the mastoid was observed to be perfectly regenerated in all cases in group II. At the second-stage operation, regeneration of the pneumatic air cells in the mastoid cavity were observed in 3 of 17 cases, but in remained 14 cases, soft tissues and/or effusion were observed in the mastoid cavity. After removing the obstacles for communication between the both mastoid and tympanic cavity, in 14 of 18 cases (77. 8%), aeration was recovered and in 10 of 18 cases (55. 6%), honeycomb-like structures were regenerated by the final assessment. In all cases in group I, connective tissues grew into the micropores of implanted artificial pneumatic bones, and no aeration was observed in the mastoid cavity at the second-stage operation.
This study demonstrated that the mastoid air cells could be regenerated with implanted artificial pneumatic air cells in the newly opened mastoid cavity with intractable chronic otitis media patients. The mastoid cortex bone plasty was effective in regeneration of the mastoid air cells by prevention of connective tissues invasion to the mastoid cavity.
This tissue engineering method may be a possible treatment for intractable otitis media because of recovering the gas exchange function of the mastoid air cells.
