Open AccessA New Landmark for the Middle Fossa Craniotomy Approach to the IAC
Author(s) -
Westbrook Benjamin James,
Crawford James V.
Publication year - 2011
Publication title -
otolaryngology–head and neck surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.232
H-Index - 121
eISSN - 1097-6817
pISSN - 0194-5998
DOI - 10.1177/0194599811415823a223
Subject(s) - operculum (bryozoa) , anatomy , medicine , middle cranial fossa , geology , biology , botany , genus
Objective Document measurements of the bony operculum of the petrous ridge as it relates to surgical anatomy of the temporal bone and thereby establish a new surgical landmark for the middle fossa craniotomy approach to the internal auditory canal. Method We analyzed 25 cadaveric temporal bones. Precise measurements were taken to identify the relationship of the bony operculum of the petrous ridge to: foramen spinosum, foramen of the greater superficial petrosal nerve, arcuate eminence, porus acousticus, and inner table of the calvarium. Results The following measurements of the operculum in relation to well established surgical landmarks of the floor of the middle cranial fossa were identified: operculum to foramen spinosum, 26.3mm [24.6‐28.0]; operculum to foramen of greater superficial petrosal nerve, 16.8mm [14.0‐19.7]; operculum to arcuate eminence, 17.3mm [15.1‐19.4]; operculum to superior border of porus acousticus, 5.3mm [3.5‐7.1]; distance from inner table of calvarium to operculum, 37.0mm [33.5‐40.5]; width of the operculum, 13.5mm [11.3‐15.7]. Conclusion This consistently present bony ridge can be used reliably to help safely identify the IAC when approached via middle fossa craniotomy, as it indicates the appropriate vertical plane of dissection.