title: Detection of human utricular otoconia degeneration in vital specimen and implications for benign paroxysmal positional vertigo.
abstract: Otoconia are assumed to be involved in inner ear disorders such as benign paroxysmal positional vertigo (BPPV). Up to now, the distinct structure and morphology of intact and degenerate human utricular otoconia has been only poorly investigated on vital specimen. In this study, human otoconia were obtained from the utricle in five patients undergoing translabyrinthine vestibular schwannoma surgery. Specimens were examined by environmental scanning electron microscopy. Intact and degenerate otoconia as well as fracture particles of otoconia and bone were analyzed by energy dispersive X-ray microanalysis (EDX) and powder X-ray diffraction (XRD). Intact otoconia reveal a uniform size showing characteristic symmetry properties. Degenerative changes can be observed at several stages with gradual minor and major changes in their morphology including fragment formation. EDX analyses reveal the characteristic chemical composition also for otoconia remnants. XRD shows that intact and degenerate otoconia as well as remnants consist of the calcite modification. In conclusion, electron microscopy serves as a standard method for morphological investigations of otoconia. Human utricular otoconia show a uniform outer morphology corresponding to a calcite-based nanocomposite. Morphological changes provide further evidence for degeneration of utricular otoconia in humans, which might be a preconditioning factor causing BPPV. In case of uncertain origin, particles can be clearly assigned to otoconial origin using EDX and XRD analyses.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University Medicine Mannheim, Ruprecht-Karls-University Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany, Leif.Walther@hno-praxis-sulzbach.de.
authors.forename: Leif Erik
authors.initials: LE
authors.lastname: Walther
authors.forename: Angela
authors.initials: A
authors.lastname: Wenzel
authors.forename: Jana
authors.initials: J
authors.lastname: Buder
authors.forename: Marc Boris
authors.initials: MB
authors.lastname: Bloching
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Kniep
authors.forename: Alexander
authors.initials: A
authors.lastname: Blödow
mesh_terms: D065635:Benign Paroxysmal Positional Vertigo / Q000175:diagnosis / Q000209:etiology; D018360:Crystallography, X-Ray / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology; D010037:Otolithic Membrane / Q000000981:diagnostic imaging / Q000648:ultrastructure; D011859:Radiography; D015203:Reproducibility of Results; D012444:Saccule and Utricle / Q000473:pathology / Q000648:ultrastructure