Three-dimensional Reconstruction Observations And Clinical Application Of The Facial Nerve Canal

BackgroundFacial nerve was one of the most prone to cranial nerve palsy, most facial nerve paralysis caused paralysis were located within the temporal bone, and facial nerve canal structure were closely related. Result in changes of facial nerve canal bone lesions with trauma, congenital malformation, cholesteatoma and tumor involving the facial nerve canal, imaging data was accurate and objective diagnosis basis. Three-dimensional reconstruction of spiral CT has powerful functions, such as multi-planar reconstruction (MPR) and curve-planar reformation (CPR), especially of spiral CT in bone structure of good display ability, make facial nerve canal structure clear, can complete display of CT image.ObjectiveUsing the multi-planar reconstruction (MPR) and curve-planar reformation (CPR) of spiral CT post processing images technology, the observation of facial nerve canal and facial nerve labyrinthine segment, anterior knee, horizontal segment, posterior knee and vertical segment on the position, shape, size line, angle, and the diameter of the facial nerve canal of geniculate fossa and the distance of the vertical segment of facial nerve canal to the surrounding structures, to provide the morphological basis for clinical diagnosis of facial nerve canal disease.Materials and methodsThe collection of Image during 2013 January to 2014 December, the adult examination were performed with temporal bone with multi-slice CT scanning images of 200 cases, no ear, temporal bone, skull base deformity and by clinical examination showed no facial nerve paralysis, including 100 cases of male,100 cases of female,21-60 years old. By imaging examination and proved by surgery were diagnosed with fractures of the facial nerve canal, cholesteatoma of middle ear and facial nerve neuroma image data of the 20 cases respectively,23-57 years old. Will be to check the original image data input CT 3D-reconstruction workstation, using ADW 4.2 reconstruction software of multi-planar reconstruction (MPR) and curve-planar reformation (CPR) technology respectively, along the facial nerve canal for image post-processing show to the whole structure of facial nerve canal. Using measuring software of 3D reconstruction workstation, measure the diameter of the facial nerve canal on the diameter and angle. Using SPSS 13.0 software for statistical data from processing, use the mean±standard deviation (x±s).Results1. Multi-planar reconstruction (MPR) of the facial nerve canal on the oblique axial images can clearly show the labyrinthine segment, anterior knee and the initial part of horizontal segment of the facial nerve, oblique sagittal images can clearly show the horizontal segment, posterior knee and vertical section of the facial nerve canal. Multi-planar reconstruction (MPR) between the left and right side, the men and women, the image and specimens were no significant difference (P>0.05), the length and width of the labyrinthine segment, horizontal segment, vertical segment and anterior knee angle, posterior knee angle were (3.66±0.39) mm, (11.50±1.06) mm, (13.68±1.05) mm and (0.89±0.14) mm, (1.10±0.11) mm, (1.10±0.14) mm, (71.88±7.98)°, (110.10±6.13)°respectively.2. Curve-planar reformation (CPR) of the facial nerve canal on the axial, coronal and sagittal images can clearly display the entire walking of the facial nerve canal. The labyrinthine segment width and posterior knee angle between the axial image and coronal, sagittal image were significantly difference (P<0.05), anterior knee angle on the axial, coronal, sagittal respectively were significant difference (P<0.05), the horizontal segment width and vertical segment width between the axial, coronal image and the sagittal image were significant difference (P<0.05).3. Multi-planar reconstruction (MPR) and curve-planar reformation (CPR) images of the facial nerve canal on the length and width of labyrinthine segment, vertical segment respectively were no significant difference (P>0.05), anterior knee angle, horizontal segment length and width, posterior knee angle were significantly difference (P<0.05).4. Multi-planar reconstruction (MPR) of geniculate fossa length of the A line, B line, C line, D line, E line between the normal group of geniculate fossa of facial nerve canal each diameter length and fracture group were significant difference (P<0.05), the normal group were (2.88±0.32) mm, (3.29±0.27) mm, (1.63±0.18) mm, (1.67±0.18) mm, (3.26±0.29) mm respectively, the fracture group diameter were significantly higher than normal group.5. Vertical segment of facial nerve canal to the posterior wall of external acoustic meatus, posterior edge of external acoustic pore, anterior wall of sigmoid sinus, facial recess distance respectively between male and female were significant difference (P<0.05), they were (3.07±0.86) mm, (12.07±2.94) mm, (8.35±2.23) mm, (1.89±0.35) mm and (2.86±0.61) mm, (10.49±2.65) mm, (7.68±2.03) mm, (1.74±0.36) mm respectively.Conclusion1. Multi-planar reconstruction (MPR) and curve-planar reformation (CPR) of facial nerve canal of CT image can be visually displayed facial nerve canal, provides important anatomic data to judge the facial nerve canal dysplasia, fracture and tumor invasion of facial nerve canal.2. Multi-planar reconstruction (MPR) of geniculate fossa of facial nerve canal were measured the diameter, and provide objective evidence for the diagnosis of geniculate fossa expansion could be used as indicators of geniculate fossa fracture.3. Measurements of the vertical segment of facial nerve canal to the surrounding structure distance, determined the facial nerve canal in temporal bone position, provides a method of positioning of the facial nerve canal decompression surgery for facial nerve lesion.