Prospective cohort comparison of bioactive glass implants and conchal cartilage in reconstruction of the posterior canal wall during tympanomastoidectomy

Pooled analysis of the evidence for open cavity, combined approach and reconstruction of the mastoid cavity in primary cholesteatoma surgery

BACKGROUND

Cholesteatoma is keratinising epithelium within the middle-ear cleft or mastoid. This disease destroys the peripheral organs of balance and hearing, with possible intracranial sequelae. The management of cholesteatoma is surgical and the primary aim is to remove the disease and prevent recurrence. Secondary aims are to obtain a non-discharging, hearing ear. Cholesteatoma surgery falls into two broad categories: open cavity surgery and combined approach surgery. A third surgical category is reconstruction of an open mastoid cavity after open surgery. This study performed a pooled analysis of the worldwide literature to compare the rates of cholesteatoma not being cured (i.e. recidivism), ear discharge and hearing change among open cavity, combined approach and reconstruction mastoid surgery for primary cholesteatoma.

METHODS

A literature search for all types of cholesteatoma surgery in the PubMed, Google Scholar and Medline databases and in published conference proceedings was undertaken.

RESULTS

There was no level 1 evidence for the best method of primary cholesteatoma surgery. The highest evidence level found (level 2; 5366 patients) shows no difference in hearing change or discharge rate between open and combined approach surgery; however, these methods fail to cure the cholesteatomas in 16.0 per cent and 29.4 per cent of cases, respectively. In a total of 640 patients, reconstruction and/or repair mastoid surgery using a variety of non-comparable techniques had a failure rate of between 5.3 per cent and 20 per cent.

CONCLUSION

The available evidence suggests that reconstruction of the posterior canal wall and/or obliteration of the mastoid may be the best surgical treatment alternative. This technique appears to provide the lowest recidivism rate combined with a low post-operative ear discharge rate.

Bioactive-glass in Oral and Maxillofacial Surgery

The use of synthetic materials to repair craniofacial defects is increasing today and will increase further in the future. Because of the complexity of the anatomy in the head and neck region, reconstruction and augmentation of this area pose a challenge to the surgeon. This review discusses key facts and applications of traditional reconstruction bone substitutes, also offering comparative information. It then describes the properties and clinical applications of bioactive-glass (B-G) and its variants in oral and maxillofacial surgery, and provides clinical findings. The discussion of each compound includes a description of its composition and structure, the advantages and shortcomings of the material, and its current uses in the field of osteoplastic and reconstructive surgery. With a better understanding of the available alloplastic implants, the surgeon can make a more informed decision as to which implant would be most suitable in a particular patient.

Temporary removal of the posterior bony canal wall with reconstruction using microplate osteosynthesis in cholesteatoma surgery: a case series and description of the technique

We describe the surgical technique of temporary removal of the posterior auditory canal wall with reconstruction and report the outcome of using this technique as a treatment method for cholesteatoma in a case series. In 32 cases of cholesteatoma surgery a technique of temporary removal of the posterior bony wall was applied. During primary surgery the posterior auditory canal wall was removed using an oscillating saw. For the purpose of reconstruction, the canal wall was repositioned and fixed using two titanium microplates (n = 26). In case the canal wall could not be reconstructed with osteosynthesis, either glass-ionomeric cement (BioCem™) was used for fixation (n = 4) or fibrin glue (Tissucol™) (n = 2) to support the posterior wall. The outcome includes the healing process in the first postoperative month, the absence of residual or recurrent disease and the successful reconstruction of the posterior auditory canal wall as evaluated during second-look surgery. When microplates where used, we saw healing problems of the canal skin in about 4% of patients. Recurrent cholesteatoma was found in 4 cases (14%), residual cholesteatoma in 8 ears (25%). In the osteosynthesis group, successful reconstruction was achieved in 25 patients (96%). In 3 out of 4 patients of the glass-ionomeric cement group (75%) excessive granulation tissue developed with extensive bony lysis. Temporary removal of the posterior auditory canal wall offers potential for the control of cholesteatoma. Our first results suggest that osteosynthesis allows for a good anatomical and functional reconstruction.

Three-dimensional bioactive glass implants fabricated by rapid prototyping based on CO(2) laser cladding

Three-dimensional bioactive glass implants were produced by rapid prototyping based on laser cladding without using moulds. CO(2) laser radiation was employed to melt 45S5 and S520 bioactive glass particles and to deposit the material layer by layer following a desired geometry. Controlled thermal input and cooling rate by fine tuning of the processing parameters allowed the production of crack-free fully dense implants. Microstructural characterization revealed chemical composition stability, but crystallization during processing was extensive when 45S5 bioactive glass was used. Improved results were obtained using the S520 bioactive glass, which showed limited surface crystallization due to an expanded sintering window (the difference between the glass transition temperature and crystallization onset temperature). Ion release from the S520 implants in Tris buffer was similar to that of amorphous 45S5 bioactive glass prepared by casting in graphite moulds. Laser processed S520 scaffolds were not cytotoxic in vitro when osteoblast-like MC3T3-E1 cells were cultured with the dissolution products of the glasses; and the MC3T3-E1 cells attached and spread well when cultured on the surface of the materials.