Objective: To explore a method of demonstrating the facial nerve anatomical landmarks under transmastoid and epitympanum approach with multi-slice CT using double oblique multi-planar reconstruction (MPR).
Method: Two temporal bone of a corpse were dissected, under transmastoid and epitympanum approach, to observe the anatomical landmarks of facial nerve. Based on that, the anatomical landmarks of facial nerve under transmastoid and epitympanum approach in 30 (60 ears) normal temporal bones of adult corpses were reconstructed using double oblique MPR in multi-slice CT. The achievement ratio was calculated and the differences among transverse plane, coronal plane, sagittal plane and double oblique were compared.
Result: The different part of facial nerve, such as mastoid segment, tympanum segment, pyramid segment, geniculate ganglion and the outer labyrinthine segment could be exposed clearly with the main anatomical landmarks, such as horizontal semicircular canal, epitympanic recess and cochleariform process through transmastoid and epitympanum approach. The image of anatomical landmarks could be showed in the same sections by double oblique multi-planar reconstruction. The double oblique multi-planar reconstruction to show the landmarks of facial nerve displaying on the same imaging is better than transverse plane, coronal plane and sagittal plane. The achievement ratio of every section is 100%.
Conclusion: Double oblique MPR is a new method to demonstrate anatomical landmarks through transmastoid and epitympanum approach in one slice. Combined with the operative approach and purpose, the reconstructive images with double oblique MPR can provide valuable information for operation.