PMC8216801_01
(a, b) Preoperative axial CT showing (asterixs) the petrous apex with bone erosion and a titanium plate covering the partially covering anterior limitation of the temporal bone. (c, d) Non-EPI DWI with coronal and axial planes. Note the diffusion restriction in the petrous apex of the left temporal bone.
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fig1
A titanium net had been implanted to stabilize the middle and posterior cranial fossae in a revision surgery six years earlier (Figure 1).
Intraoperative image showing the petrous apex with the cholesteatoma matrix prior to removal. The superior semicircular canal has been plugged, sealed, and partly amputated.
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fig2
Hopkin's wide-angle endoscope was used to control the extension and removal of the cholesteatoma of the petrous apex that could not be assessed with the microscope (Figures 2 and 3).
3D reconstruction of CTs. (a) The preoperative scan reconstruction. (b) The postoperative scan exhibiting the defect of the petrous apex after the partial translabyrinthine approach.
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fig3
Hopkin's wide-angle endoscope was used to control the extension and removal of the cholesteatoma of the petrous apex that could not be assessed with the microscope (Figures 2 and 3).
Coronal CT of the amputated superior semicircular canal (asterix) and the postoperative defect of the left petrous apex.
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fig4
All cholesteatoma matrixes were eliminated from the petrous apex (Figure 4).
Left ear, pre- ( air conduction and  bone conduction) and postoperative ( air conduction and  bone conduction) pure-tone audiogram. Hearing thresholds remained on the operated left ear one year after surgery.
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fig5
The preoperative hearing threshold could be preserved by superior semicircular canal plugging (Figure 5).