Cartilage-wire-fascia compact total ossicular replacement prosthesis in one-stage cholesteatoma surgery

Evaluation on shear bond strength of different glass ionomer and hydroxy apatite cements used in ossiculoplasty

BACKGROUND

Glass ionomer cements (GIC) have been widely used in dentistry for many years. In recent years, GIC have also been used for ossiculoplasty. The bond strength of GIC used in ossiculoplasty and the way they may change over the years in the cementation area are being questioned. The bonding strength of the substance may be of importance for long-term outcomes.

AIMS

The aim of this study was to investigate the bond strength of different GIC on ossicles.

STUDY DESIGN

In vitro study.

METHODS

Twenty ossicles were obtained from patients who had undergone ear surgery. All specimens were randomly divided into four subgroups. All specimens were inserted into a specially designed apparatus for shear bond strength (SBS) testing. The tested materials [Aqua Meron (AM), Aqua Cem (AC), Ketac Cem (KC), and Otomimix CPB (OH)] were prepared and applied according to the manufacturer's instructions. The SBS was tested using a universal testing machine at a crosshead speed of 0.5 mm/min.

RESULTS

The mean SBSs were found to be 13.28 MPa, 23.43 MPa, 8.51MPa, and 1.78 MPa for AM, AC, KC, and OH, respectively. AC had the highest SBS, which was statistically significantly different from that of KC and OH (p<0.05). Both AM and KC had higher SBS than OH (p<0.05).

CONCLUSION

The results obtained in this study by investigating the bone-bonding strength of cements widely used in ossiculoplasty demonstrate that some of these substances have a greater ability to bond to ossicles compared to others. Further clinical investigations are needed to test different parameters.

The use of bone cement for ossicular chain defects

Bone cement is a good and cheap option for some ossicular chain problems such as incudostapedial re-bridging. The purpose of this retrospective study is to evaluate the audiologic results after reconstruction of three different types of ossicular chain defects, using bone cement. Group 1 consists of 42 patients who underwent an ossiculoplasty using bone cement between the damaged long process of the incus and an intact stapes superstructure. Group 2 consists of 46 patients in which incus interposition between malleus and stapes superstructure was performed, using bone cement to fix the interposed incus. For group 3, consisting of 32 patients who had a present malleus, a defective long process of the incus and a missing stapes superstructure, a re-shaped incus was placed between the stapes footplate and the malleus and bone cement was again used as a fixator. Preoperative and postoperative pure-tone audiometric findings were obtained and hearing differences were assessed. The mean preoperative and postoperative air-bone gaps were 34.8 and 15.6, 35 and 18.4, and 43.4 and 19.8 for groups 1, 2, and 3, respectively. There was a significant improvement in hearing outcomes in all the groups when comparing preoperative and postoperative mean air-bone gaps (p < 0.001). The postoperative air-bone gap was ≤20 dB in 76 % of patients in group 1, 64 % of patients in group 2, and 46 % of patients in group 3. Bone cement is an effective and cheap option for some ossicular chain problems such as incudostapedial re-bridging. It may also be used to fix the interposed incus to the stapes superstructure and/or malleus to avert displacement.

[Microsurgical middle ear operations : Variability of the audiometric results from frequency variations]

INTRODUCTION

The audiometric results after reconstructive tympanic surgery on 504 patients carried out between October 2005 and October 2007, including 190 cases of tympanoplasty type I and 314 cases of tympanoplasty type III according to Wullstein, were retrospectively analyzed at the Department of Otolaryngology, Ruprecht-Karls-University in Heidelberg.

PATIENTS AND METHODS

To investigate the influence of the frequencies used to compare the outcome, the pure tone average air-bone gaps (PTA-ABG) of the preoperative and postoperative audiograms of tympanoplasties type I and III were analyzed. The frequencies covered the ranges of 0.5 kHz, 1 kHz, 2 kHz, 4 kHz and 6 kHz. In each case the 3-frequency, 4-frequency and 5-frequency analyses were calculated for the different surgical groups.

RESULTS

The 3-frequency analysis (0.5 kHz, 1 kHz and 2 kHz) of the type 1tympanoplasties were 18.8 ± 11.8 dB preoperative and 12.3 ± 11.8 dB postoperative. In 58.9% of cases the PTA-ABG ≤ 10 dB and in 86.7% it was ≤ 20 dB. The 3-frequency analysis showed that the tympanoplasties type III had a PTA-ABG of 30.6 ± 15.3 dB preoperatively and 21.8 ± 15.1 dB postoperatively. In 30.4% of cases the PTA-ABG was ≤ 10 dB and ≤ 20 dB for 56%.

DISCUSSION

The detailed itemization of frequencies in this study and the consequent opportunity to modify the frequency range, allowed the impact of this selection on the PTA-ABG to be illustrated and various comparisons with other studies could be carried out. In this article, the exclusion criteria were dealt with liberally and risk patients were also included and data from patients who displayed prognostic risks regarding the successful surgery in terms of the audiometric reports were integrated. These prognostic risks were due to the poor aeration of the tympanum and recent (sometimes diverse), pre-surgery as well as chronic inflammatory processes. This study has proved that all surgery collectives showed significant improvements of the PTA-ABG. Therefore, all surgery collectives (measured against the audiometric evaluation) benefited from the surgery.