In conventional practice, the application of temporalis fascia or perichondrium grafts over the epithelial layer of the tympanic membrane (TM) often led to entrapment of the squamous epithelium beneath the graft, which was considered a potential cause of iatrogenic middle ear cholesteatoma and the formation of epithelial pearls of grafts during myringoplasty [1,2]. However, this conclusion has not been substantiated by evidence, relying primarily on experimental studies rather than clinical investigations.

The conventional over-underlay technique involves placement of the graft medial to the TM remnant and lateral to the handle of the malleus [3]. In recent years, we have adopted a modified over-underlay technique for the placement of cartilage-perichondrium grafts. In this technique, the cartilage graft is placed medial to the TM remnant, whereas the perichondrium graft is placed lateral to the epithelial layer [4,5]. This technique was modified based on the observation that the eardrum flap of perforation edges did not develop cholesteatoma in most of patients with traumatic perforation [[6], [7], [8], [9]]. Interestingly, the eardrum flap gradually undergoes necrosis and migrates into the external auditory canal (EAC) [10,11]. Based on this observation, we propose that the perichondrium flap is analogous to the eardrum flap and should be managed similarly by overlaying the epithelial layer. The objective of this study evaluated the 3-year graft outcomes and risk of iatrogenic cholesteatoma following cartilage-perichondrium over-underlay technique with perichondrial graft covering the native TM epithelium for large perforations.