Study on the relationship between distance from margin of sigmoid sinus to posterior wall of external acoustic canal and retrolabyrinthine space

Objective By measuring the distance from the margin of sigmoid sinus to posterior wall of external acoustic canal and posterior semicircular canal in order to provide anatomical basis for minimally invasive operation on cerebellopontine angle under the assistance of endoscopy through retrolabyrinthine approach.Methods Fifteen head specimens(30 sides) of adult cadavers fixed with formalin were applied for study of radical mastoidectomy,labyrinthine skeletization and anatomy of sigmoid sinus.The distances from the margin of sigmoid sinus to posterior wall of external acoustic canal and posterior semicircular canal had been measured,then the figures were statistically analyzed.Results The distances from the margin of sigmoid sinus to posterior wall of external acoustic canal and posterior semicircular canal were 15.65±1.26 mm and 10.83±0.85 mm respectively,and they had significant relativity(r=0.672,P0.01).Conclusion By measuring the distance from the margin of sigmoid sinus to posterior wall of external acoustic canal and retrolabyrinthine space can be indirectly estimated,then it can provide more information about cerebellopontine angle for minimally invasive operation under the assistance of endoscopy through retrolabyrinthine approach.