title: Vascular findings in the facial nerve canal in human temporal bones with diabetes mellitus.
abstract: OBJECTIVE
  To identify pathological changes to vessels in the facial nerve canal among patients with diabetes mellitus.
  
  
  METHODS
  Histopathologic human temporal bone study.
  
  
  METHODS
  This study examined 26 temporal bones from 13 patients with type 1 diabetes mellitus and 40 temporal bones from 20 patients with type 2 diabetes mellitus. Temporal bones from patients with type 2 diabetes mellitus were divided into 2 groups according to the method of diabetes management: insulin (n = 11) and oral hypoglycemic agents (n = 9). For the control groups, 16 age-matched normal temporal bones from 11 subjects were recruited for type 1 diabetes mellitus and 11 age-matched normal temporal bones from 8 subjects were recruited for type 2 diabetes mellitus.
  
  
  METHODS
  Thicknesses of vessel walls in the labyrinthine, tympanic, and mastoid portions of the facial nerve canal were examined under light microscopy.
  
  
  RESULTS
  Vessel walls for all portions of the facial nerve canal were significantly thicker in diabetic patients than in normal controls for both types 1 and 2 diabetes. In type 2 diabetic patients, vessel wall thickness was significantly greater in patients treated with insulin therapy than in patients treated via oral hypoglycemic agents.
  
  
  CONCLUSIONS
  The facial nerve in patients with diabetes mellitus is ischemic compared with normal controls. These findings suggest a histologic basis for the high incidence and difficulty in achieving improvement of facial nerve palsy in patients with diabetes mellitus.
authors.affiliation: Otitis Media Research Center, Department of Otolaryngology, University of Minnesota, Minneapolis, 55455, USA.
authors.forename: Shin
authors.initials: S
authors.lastname: Kariya
authors.forename: Sebahattin
authors.initials: S
authors.lastname: Cureoglu
authors.forename: Norimasa
authors.initials: N
authors.lastname: Morita
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Nomiya
authors.forename: Rie
authors.initials: R
authors.lastname: Nomiya
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Schachern
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nishizaki
authors.forename: Michael M
authors.initials: MM
authors.lastname: Paparella