Middle ear congenital cholesteatoma: systematic review, meta-analysis and insights on its pathogenesis.

PURPOSE: Congenital cholesteatoma (CC) presents as a white pearl-like lesion behind a normal tympanic membrane (TM), without a history of otorrhea, infection, perforation or previous otologic surgery. Several recent studies provided new data improving this pathology characterization. The aim of this paper is to expand the knowledge about CC and to provide new insights on its pathogenesis. METHODS: The study consisted of two main research parts: (1) systematic review and meta-analysis; (2) medical literature review englobing anatomy, histology, embryology and congenital pathology of the ear. RESULTS: The search strategy identified a total of 636 papers. Seventy retrospective studies were included. A total of 1497 cases were studied and the mean age was 6.58 years, with a male-female ratio of 3:1, 34% were asymptomatic, 26% had hearing loss and 2% had facial dysfunction/paralysis. The overall estimate for antero-superior quadrant involvement was 0.70 [95% confident interval (CI) 0.64-0.76], in the postero-superior quadrant was 0.60 (95% CI 0.52-0.69), in the antero-inferior quadrant was 0.32 (95% CI 0.23-0.41), in the postero-inferior quadrant was 0.38 (95% CI 0.29-0.47), in the attic was 0.53 (95% CI 0.43-0.63) and in the mastoid was 0.33 (95% CI 0.26-0.41). More advanced Potsic stages were present in older patients. The most likely inclusion place seems to be between the pars flaccida and the upper quadrants of the pars tensa. CONCLUSIONS: During the last decades, a substantial improvement in CC diagnosis and management had been achieved. The presented mechanism seems to explain most of middle ear CC.

Pars tensa and tympanicomalleal joint: proposal for a new anatomic classification.

PURPOSE: The tympanic membrane (TM) belongs to the ear. Despite its place in the ear anatomy, can we give it also a different anatomic classification? The main objective is to clarify the nature of TM, tympanic bone and malleus to propose a new anatomic classification. METHODS: This cadaveric study was performed in two human heads and six fresh temporal bones. A study of the temporomandibular joint, external acoustic meatus (EAM), TM and middle ear structures was conducted. A medical literature review englobing anatomy, embryology, histology and phylogeny of the ear was performed and the results were compared with the results of the dissection. RESULTS: The external ear is constituted by the auricle and the EAM. This last segment is made by a cartilaginous and an osseous portion. The osseous portion of the EAM is constituted mainly by tympanic bone. The external ear is separated from the middle ear by the TM. Inside the middle ear, there are three ossicles: malleus, incus and stapes, which allow the conduction of sound to the cochlea. Based on the anatomic dissection and medical literature review of the tympanic bone, malleus and TM, we propose that these structures are interconnected like a joint, and named it "Tympanicomalleal joint". CONCLUSIONS: It seems that the TM can be part of a joint that evolved to improve sound transmission and middle ear protection. Thinking TM has part of a joint may help in the development of more efficient reconstructive surgical techniques.