Is a Biological Scaffold Needed for the Repair of Traumatic Tympanic Membrane Perforations?

Abstract

I read with great interest the article entitled ‘‘Acellular Collagen Scaffold With Basic Fibroblast Growth Factor for Repair of Traumatic Tympanic Membrane Perforation in a Rat Model’’ by Yao et al. The authors compared the efficacy of an acellular collagen scaffold (ACS) in combination with basic fibroblast growth factor (bFGF) for the repair of a traumatic tympanic membrane (TM) perforation in a rat model, and they concluded that an ACS is an effective TM scaffold and a carrier for bFGF. However, some issues remain to be considered. What is the clinical significance of this study? The ACS provided a scaffold for epithelial migration, and the authors suggested that this facilitated the healing of TM. Previous authors also generally accepted that regeneration of the TM was dependent on epithelial proliferation and migration with the aid of a fibrous scaffold layer, and perforations will fail to heal in the absence of a fibrous layer. However, clinical observations indicate that the failure of perforations to heal is due to internal or external migration of the epithelium and not the absence of a fibrous layer (Figure 1). Recently, we performed a series of clinical studies of a bFGF, epidermal growth factor (EGF), and 0.3% (w/v) ofloxacin ear drops with and without the scaffold for the repair of traumatic perforations. Although the topical application of bFGF, EGF, or ofloxacin ear drops improved the closure rate and reduced the closure time compared with spontaneous healing, surprisingly, neither the closure rate nor the closure time differed significantly among the 3 treatment groups or with and without the scaffold. We also performed a clinical study of physiological saline on the TM healing and found similar results (unpublished). The current view is that a solution alone or scaffold alone could accelerate the TM healing, and a biological scaffold is not required. Yao et al did not compare the healing effects of ACS, bFGF, and other solutions or scaffolds but examined only simple spontaneous healing. The TM healing seems like a simple question, but many interesting issues (eg, whether the scaffold is actually necessary and whether conventional dry treatment is reliable) are worth further discussion. Experimental studies mainly deal with clinical treatment, and biological materials should provide simple treatment, good efficacy, and low medical costs without being complicated and expensive. Our series of clinical studies suggest that the TM healing was similar to the healing of skin wounds, which is dependent on a moist environment. As Okan et al said, the best environment for healing is neither too dry nor too wet. However, the TM is a specialized structure located deep in the external auditory canal, and keeping it moist is an important issue.