Epithelial migration in open mastoidectomy cavities.

Twenty patients who had undergone open cavity mastoidectomy for chronic middle ear disease were selected for study. Following initial microscopic aural toilet, each cavity was painted in its medial aspect with a marker solution of Bonney's Blue dye. Each patient was assessed at weekly intervals for a minimum of three months following application of dye, and a photographic record made of the cavity. Information was also sought regarding the clinical behaviour of the mastoid cavities, with particular regard to degree of otorrhoea, and accumulation of debris. Migration of epithelium inferred by visible movement of dye occurred in 17 of the 20 mastoid cavities. In all these cases migration occurred in a medial to lateral direction, towards the exterior. In two cases there was no visible migration throughout the period of observation, and inspection after six months revealed the dye to be still present in the original position. Both these cases were of dry trouble-free cavities in which accumulation of debris did not appear to be a problem. This finding calls into question the assumption that clean trouble-free cavities are maintained by a satisfactorily functioning epithelial migration. In the four cavities which suffered from intermittent otorrhoea, epithelial migration occurred at a similar rate to that in dry cavities.