title: Middle ear gas pressure regulation: the relevance of mastoid obliteration.
abstract: OBJECTIVE
  To establish a mathematical model of middle ear gas pressure regulation and to discuss potential implications for pathophysiology-oriented theoretical approach to middle ear surgery, with particular attention to mastoid obliteration.
  
  
  BACKGROUND
  Numerous studies support that small mastoid volume is associated with cholesteatoma. Latest studies show that mastoid obliteration is an effective technique to lower the recurrence rate in these ears.
  
  
  METHODS
  A mathematical model was used to predict the development of gas pressure balance in the function of different middle ear volumes (VME), considering normal and dysfunctional Eustachian tube. Published data as gas pressure input values and our 3D CT reconstruction data in healthy and pathologic middle ears of children were applied.
  
  
  RESULTS
  The model predicted ≤6.66 daPa pressure fluctuations in VME ≥3 ml, compared to ≥16 daPa of a VME ≤1 ml at perfect ET function, because of the different pressure change rate and pressure buffer effect of the MEs. Substantially larger fluctuations can be expected in a VME <3 ml with malfunctioning ET. Modeling mastoid obliteration predicts similar pressure fluctuations to a VME ≥3 ml resulting from elimination of gas exchange surface.
  
  
  CONCLUSIONS
  Pressure change is faster in smaller MEs than in larger ones. Healthy MEs between 3 and 6 ml are very sensitive to the duration of a potential ET dysfunction to develop ME pathology. In MEs with poor mastoid pneumatization and dysfunctional ET, typical in cholesteatoma cases, mastoid obliteration as surgical reduction of mucosal surface for gas exchange can improve ME gas pressure balance resulting in better long-term outcome.
authors.affiliation: *Department of Pediatric Otorhinolaryngology, Heim Pal Children's Hospital, 13 Delej utca, H-1089 Budapest, Hungary; †Budapest University of Technology and Economics, 3-9 Műegyetem rkp, H-1111 Budapest, Hungary; ‡Faculty of Engineering, University of Szeged, 13 Dugonics square, H-6720 Szeged, Hungary; and §Department of Otorhinolaryngology and Head and Neck Surgery, Health Science Centre, University of Debrecen, 98 Nagyerdei krt., H-4032 Debrecen, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Csakanyi
authors.forename: Gabor
authors.initials: G
authors.lastname: Katona
authors.forename: Denes
authors.initials: D
authors.lastname: Konya
authors.forename: Ferenc
authors.initials: F
authors.lastname: Mohos
authors.forename: Istvan
authors.initials: I
authors.lastname: Sziklai
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018424:Cholesteatoma, Middle Ear / Q000503:physiopathology / Q000601:surgery*; D003198:Computer Simulation; D004432:Ear, Middle / Q000503:physiopathology* / Q000601:surgery; D005064:Eustachian Tube / Q000503:physiopathology* / Q000601:surgery; D005740:Gases; D006801:Humans; D008416:Mastoid / Q000503:physiopathology / Q000601:surgery*; D008954:Models, Biological; D013506:Otologic Surgical Procedures; D010313:Partial Pressure; D012008:Recurrence
chemical_list: D005740:Gases