RESUMO
PURPOSE: In this study, we aimed to determine whether or not COM leads to loss of spiral and Scarpa ganglion neurons. METHODS: From the human temporal bone (HTB) collection at the University of Minnesota we selected human temporal bones with COM, defined as the presence of clinically intractable tissue abnormalities in the middle ear (cholesteatoma, perforation of the eardrum, granulation tissue, fibrosis, tympanosclerosis, and cholesterol granuloma). We also selected HTBs from donors with no ear diseases as controls. We quantitatively analyzed the number of spiral and Scarpa ganglion cells and compared the results obtained in the control and study groups. RESULTS: In both COM and control groups we observed a significant negative correlation between age and number of both spiral (R = -0.632; P < 0.001; 95% CI - 0.766 to - 0.434) and Scarpa ganglion (R = - 0.404; P = 0.008; 95% CI - 0.636 to - 0.051) cells. We did not find any significant differences in the number of spiral ganglion cells (in total or per segment) or in the density of Scarpa ganglion cells (in each vestibular nerve or both) in the COM group as compared with controls (P > 0.05). CONCLUSIONS AND RELEVANCE: Our results did not demonstrate significant loss of cochlear or vestibular peripheral ganglion neuron loss in HTBs with COM as compared with controls.
Assuntos
Otite Média , Nervo Vestibular , Cóclea , Humanos , Neurônios , Gânglio Espiral da Cóclea , Osso TemporalRESUMO
HYPOTHESIS: The presence of bony inner ear malformations may associate with a number of anatomical abnormalities affecting the middle ear structures. Those malformations may create pitfalls and complications for cochlear implantation. BACKGROUND: Inner ear malformations associate with varying degrees of hearing loss, and frequently require cochlear implantation for hearing rehabilitation. Therefore, the abnormalities affecting the middle- and inner-ear structures may increase the risk of surgical complications. METHODS: We examined 38 human temporal bones from donors with bony inner ear malformations. Using light microscopy, we analyzed the presence of abnormalities in the structures of the middle- and inner-ear. RESULTS: Our collection comprises of 38 specimens with inner-ear malformations (cochlear aplasia, nâ=â3; cochlear hypoplasia, nâ=â30; incomplete partition, nâ=â3; isolated vestibular malformation, nâ=â2). The anatomy of the middle ear was abnormal in most temporal bones with cochlear aplasia, cochlear hypoplasia, and incomplete partition type I (40%-100%). Some of those abnormalities (hypoplastic or obliterated mastoid, 55.2%; aplastic or obliterated round window, 71.0%; aberrant course of the facial nerve, 36.8%) may hinder the access to the round window using the conventional facial recess approach for cochlear implantation. The cochlear nerve and associated bony structures (internal auditory canal and bony canal for cochlear nerve) were normal in 71.0% of all temporal bones with inner ear malformations. CONCLUSION: Each different type of malformation may create specific surgical challenges to surgeons. Comprehensive preoperative imaging is fundamental toward the surgical success of cochlear implants in patients with malformations. Alternatives to circumvent those middle- and inner-ear abnormalities and potential complications are further discussed.