Pyramidal eminence and subpyramidal space: an endoscopic anatomical study.

OBJECTIVES/HYPOTHESIS: To describe retrotympanic endoscopic anatomy, especially the pyramidal eminence and contiguous spaces.

STUDY DESIGN: This was an anatomical study on a prospective case series.

METHODS: The anatomy of the retrotympanum was studied by endoscopy in nine patients affected by cholesteatoma who underwent tympanomastoid surgery and in six temporal bone dissections.

RESULTS: Pneumatization of the sinus tympani and posterior tympanic sinus or both, noted in 12 ears out of 15, may give rise to a recess beneath the pyramidal eminence, which we have called the subpyramidal space. This space can manifest with a variable degree of depth, shape, or extent depending on the shape and dimensions of the pyramidal eminence.

CONCLUSIONS: Endoscopic exploration of the middle ear may guarantee a very good exposure of retrotympanic structures, allowing detailed anatomical descriptions of hidden areas. Improvement in our knowledge of the anatomy may decrease the possibility of residual disease during cholesteatoma surgery.