Radical Mastoidectomy: Long Term Results and Analysis

Abstract
We performed a long-term, retrospective, non-controlled study on the anatomic (drainage), functional (hearing) and reconstructive (ossiculoplasties) results of both radical and modified radical mastoidectomies. For ossicular chain reconstruction we used bioceramic implants of autochthonous origin and defined the statistical relevant factors that could influence the rate of implant rejection. In a cohort of 200 patients with mastoidectomies, we performed ossiculoplasies with bioceramic implants on 108 patients and followed them clinically for a period of minimum 7 years. We have defined several factors that could influence the results of the implantation and studied the statistic correlations. The rejection rate after 9.12 years was 21% (23 patients). Histological integration rate was 79% (85 patients), similar to results reported in literature for both bioceramic and titanium implants. Hydroxyapatite has many of the ideal characteristics required to be a good prosthesis with a high degree of biocompatibility, very low extrusion rate, low risk of disease transmission and good functional results. Although perhaps considered of historical interest, bioceramic implants are cheaper and can be produced locally, which is a great advantage for struggling economies.

On the same inital cohort of 200 patients we defined the functional results by analitical function of the severity and the period of evolution of disease. These criteria can be defined by assessing the patient's pre-operative absolute hearing thresholds (AHT), bone conduction threshold (BCT), and age at the time of surgery. The two parameters evolve inversely proportional to the functional results, resulting in a comprehensive and exact analytical tool. The global average hear gain ratio was 32% and the ratio for unmodified pre-operative hearing (statu-quo ante) was 61%. With favorable prognostic factors the average gain rate was 56% and the hearing-loss rate was 5% (1- dB SPL nominal value). The maximum ratio for gain was 81% and for hearing loss was 0%.

The drainge (anatomic) results, similar to previously published functional results, are defined by analitical function of the severity and the period of evolution of disease. Our main goal was to define the situations and factors (presence of complications, type of disease, type of tympanic perforation or status of ossicular chain) that influence the drainage results and could give us some kind of anatomical prognosis. The follow-up started at the moment of complete epithelization for each cavity as time represents the main study comparison criteria. Drainage failure was assessed by the number of otorrhea episodes. We conclude that practically and ideally, we can clean out a maximum of 84% of the mastoid and petrous cells. Our results of 78% draninage success are congruent to this theory. The remaining 16% of cells may contain irreversible lesions.