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A randomized, blinded study of canal wall up versus canal wall down mastoidectomy determining the differences in viewing middle ear anatomy and pathology.

  • Hulka, G F
  • McElveen, J T Jr
Published Article
The American journal of otology
Publication Date
Sep 01, 1998
PMID: 9752963


Statistical analysis shows good reproducibility and randomization of this study. The canal wall down tympanomastoidectomy allowed for superior viewing of the three locations, sinus tympanic, posterior crus of stapes, and lateral at the tympanum, as they were marked in the study. This study shows the potential for improved visualization via the canal wall down tympanomastoidectomy. A significant amount of literature written by individuals and otology group practices is available retrospectively comparing the advantages and disadvantages of intact canal wall versus canal wall down mastoidectomy procedures for approaching middle ear pathology. In the interest of objectively evaluating the differences between these two approaches, we have studied temporal bones in a prospective randomized, blinded study comparing the two. Twelve bones were used and observed twice, once in each of 2 sessions. All bones were viewed in two dissections: intact canal wall and canal wall down mastoidectomy. Four points were marked on each temporal bone in three different colors applied in a randomized order to eliminate observer expectation. The four points marked include sinus tympani, posterior crus of the stapes footplate, lateral epitympanum, and Eustachian tube orifice. Both intact canal wall and canal wall down bones were provided randomly to the observer at each viewing session. Before the observer was allowed to see the dissections, those requiring replacement of the canal for the first session of the study had this done in a method using native posterior bony canal. Temporal bones were presented to an expert otologist in a randomized fashion with each temporal bone being placed in a temporal bone bowl holder and specialized framework, allowing for rotation and repositioning approximating the experience in an operating room setting. For each temporal bone, the observer filled in a questionnaire describing his or her observations by denoting both location and color of marks observed. (ABSTRACT TRUNCATED)

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