الفهرس 
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Abstract
Ossiculoplasty aims to rebuild the continuity and or mobility of the ossicular chain which may have been fixed, disrupted, or destroyed. The cause of ossicular damage (i.e., discontinuity, fixation) is cholesteatoma or chronic suppurative otitis media in more than 80% of patients. (Batista, 2004)
The challenge during ossiculoplasty has been how to achieve a stable reliable connection between the tympanic membrane and mobile stapes footplate that will provide the best long term hearing results. (Celik et al, 2001)
The ideal ossicular prosthesis should be manageable, versatile, biocompatible and stable over time. (Artuso et al, 2004)
Bioglass 45S5 is a bioactive glass ceramic which has the most potent effect on bone cell function.
In an experimental study done by Merwin (1982); it was discovered that the bioactive glass bonded not only with the remaining bone stock of the ossicles, but also directly to the tympanic membrane via collagen attachment to the surface of the glass.
This was the first time any implant material demonstrated direct bonding to the soft tissue of the tympanic membrane, by this time, the clinical use of Bioglass in ossiculoplasty was limited due to the difficulty in trimming the material and instability in infected media. Recent advances in biomaterial technologies led to the development of new forms of Bioglass that can overcome these difficulties.
Objective:
The objective of this study was to evaluate the short term results of using Bioglass as middle ear ossicular replacement prostheses.
Methodology:
Between December 2002 and November 2004, ossicular reconstruction using Bioglass prostheses was carried out in 30 patients presented with conductive hearing loss with or without chronic suppurative otitis media. Ossicular reconstruction was done using Bioglass incus bridging prostheses in 7 patients (groupI), using Bioglass PORPs in 10 patients (groupII) and using Bioglass TORPs in 13 patients (groupIII).
Middle ear risk index (MERI) developed by Kartush (2000) was used in our study as a means to improve the accuracy of reporting ossiculoplasty results and to allow meaningful comparison among studies.
Post operative follow up included clinical, audiologig and radiologic evaluation.
Results:
Cases were 17 males and 13 females with an age range 14 - 42 years.
MERI ranged from 1-3 in group I, 2-7 in group II and 3-8 in group III, it showed significant negative correlation with hearing outcome (gain) after 12 months in the study groups.
According to the American academy of otolaryngology-Head and neck surgery’s committee in 1995, closure of the air-bone gap to within 20 dB postoperatively is considered successful.
In groupI, the mean preoperative ABG was 50.4 dB while it was 14.57 dB 12 months postoperatively with 36 dB gain. ABG closure to within 20 dB was achieved in 6 of 7 cases of this group (85.7%).
In groupII (PORPs) the mean preoperative ABG was 36 dB while it was 22.8 dB after 12 months with 13.9 dB gain, the ABG closure to within 20 dB was achieved in six cases out of ten (60%) while it was less than 30 dB in the rest of this group (30%).
In groupIII, (TORPs) the mean preoperative ABG was 38.8 dB while it was 35.5 dB after 12 months with 3.9 dB gain. Closure of ABG to within 20 dB was not achieved in any case of this group. We obtained ABG closure to within 30 dB in 7 out of 11 cases (63%).
It is to be noted that the ABG gains were positively correlated significantly with the preoperative ABGs in all patients, while age was not.
There were no significant changes in the speech discrimination scores.
Few complications were encountered in this study, displacement occurred only in one case (3.3%), graft perforation with prostheses extrusion and recurrent cholesteatoma in two cases (6.7%), significant vertigo occurred in one case (3.3%) .
Tinnitus occurred in 40% of cases in the first months of the study.
No sensorineural affection or dead ears were encountered in this study, also no foreign body or allergic reactions to the material occurred.
Thin sections CT scans were taken in the postoperative period to assess presence, position of the prostheses if possible; also to measure the bone density of the prostheses with time and to monitor any other complication.
There was progressive increase in prostheses densities in comparison to the densities of the near-by labyrinthine bones; the mean percentages of material density after 1 month were 67.7% in groupI, 67.2% in groupII, and 58.2% in groupIII (average= 64.4%) while they were 92.6%, 86.7% and 77.2% after 6 months respectively (average= 85.5%).
It was noted that material density showed inverse significant correlation with age of the patient.
In conclusion; Bioglass is a promising material for ossiculoplasty in the presence of stapes suprastructures, but it needs special modification before continuing using as TORP.
Long term follow up is also recommended to assess the maintenance of hearing improvement with time.
The MERI is recommended as a uniform reporting protocol.