Dear Editors,
I would like to address the article titled ‘Spontaneous closure of traumatic tympanic membrane perforations: observational study’ by Jellinge et al.Reference Jellinge, Kristensen and Larsen1
Their work is very important. I agree with the authors in that traumatic tympanic membrane perforation has the highest closure rate with spontaneous healing. Regarding inverted and everted edges, however, the authors cited my paper and wrote, ‘Previous reports of the importance of inverted and everted edges are contradictory,Reference Lou, Tang and Yang2, Reference Lou3 but it has been stated that the type of epithelial migration has importance for closure time but not for closure rate’.Reference Lou3
I feel that Jellinge et al. misunderstand the two concepts of inverted edge and outward epithelial migration, which resulted in a misquotation. Inverted and everted edges refer to the remaining residual eardrum at the perforation margin when tympanic membrane perforation occurred, and the edge comprises the three layers of the eardrum. Studies have suggested that an inverted edge may migrate inward into the middle tympanic cavity, which results in failure to heal, or the development of a middle-ear cholesteatoma.Reference Armstrong4–Reference Winerman, Man and Segal6 Our study suggested that the inverted and everted edges gradually become necrotic, form a crust, and migrate into the external auditory canal. Consequently, an inverted edge does not affect the outcome of spontaneous healing.Reference Lou and He7 Other studies obtained similar findings.Reference Park, Kim, Lee and Lee8–Reference Camnitz and Bost10 By contrast, outward migratory epithelium is the outer squamous epithelial layer of the tympanic membrane on the perforation edge that proliferates and migrates upward away from the centre of the perforation during the spontaneous healing process. This non-centripetal migration of proliferating epithelial cellsReference Lou3 may occur in perforations with and without inverted edges. It is merely an abnormal or pathological epithelium migration that occurs during the healing of traumatic tympanic membrane perforation, not another means of eardrum healing.
Our study showed that the perforation can start to heal only when the outward epithelial migration pattern evolves into a centripetal migration pattern. Once outward epithelial migration occurs, it may prolong and impede the closure of traumatic eardrum perforation.Reference Lou3
Based on these studies, I realise that the description of the quote in their Discussion confused inverted edge and outward migratory epithelium.
