title: Stapes surgery: the diameter of the long process of the incus.
abstract: OBJECTIVE
  The aim of this study was to examine the long process of the incus in respect of its shape and its dimensions at the site of the attachment of a stapes prosthesis.
  
  
  BACKGROUND
  One of the complications in stapes surgery is the erosion of the long process of the incus at the site of the attachment of the prosthesis, resulting in a fluctuating conductive hearing loss. Knowing the dimensions of the attachment site of the prosthesis at the long process of the incus will make it possible to optimize the size of the prosthesis loop.
  
  
  METHODS
  The incus was obtained from 11 patients who had undergone middle ear surgery for hearing improvement or cholesteatoma removal. The ossicles were kept in 4% paraformaldehyde and were processed for histological examination after decalcification in ethylenediamine tetra-acetic acid. The 5-microm slices were stained with toluidine blue and examined in the light microscope. Using digitized video images of the histological slices, the diameters, circumference, and surface of the specimens were determined.
  
  
  RESULTS
  The diameter of the long process of the incus at 1.4+/-0.28 mm from the tip, which is the average site of prosthesis attachment, showed an oval shape with a minimum diameter of 0.66+/-0.05 mm, a maximum diameter of 0.81+/-0.1 mm, and a circumference of 2.46+/-0.23 mm.
  
  
  CONCLUSIONS
  The loop of a stapes prosthesis should have the following dimensions: diameter 0.9 mm, loop length of 2.2 mm, and opening of loop 0.7 mm. However, the material of the prosthesis and its malleability are also important factors.
authors.affiliation: ENT-Department, University of Regensburg, Regensburg, Germany, and ORL-Zentrum, Hirslanden Klinik, Zürich, Switzerland. pingling.kwok@klinik.uni-regensburg.de
authors.forename: Pingling
authors.initials: P
authors.lastname: Kwok
authors.forename: Ugo
authors.initials: U
authors.lastname: Fisch
authors.forename: Otto
authors.initials: O
authors.lastname: Gleich
authors.forename: Klaus
authors.initials: K
authors.lastname: Achhammer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Strutz
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007188:Incus / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged; D019933:Ossicular Replacement / Q000379:methods* / Q000592:standards; D013201:Stapes Surgery / Q000592:standards