Sectional anatomy aid for improvement of decompression surgery approach to vertical segment of facial nerve.

The aim of this study was to find a surgical approach to a vertical segment of the facial nerve (VFN) with a relatively wide visual field and small lesion by studying the location and structure of VFN with cross-sectional anatomy. High-resolution spiral computed tomographic multiplane reformation was used to reform images that were parallel to the Frankfort horizontal plane. To locate the VFN, we measured the distances as follows: from the VFN to the paries posterior bony external acoustic meatus on 5 typical multiplane reformation images, to the promontorium tympani and the root of the tympanic ring on 2 typical images. The mean distances from the VFN to the paries posterior bony external acoustic meatus are as follows: 4.47 mm on images showing the top of the external acoustic meatus, 4.20 mm on images with the best view of the window niche, 3.35 mm on images that show the widest external acoustic meatus, 4.22 mm on images with the inferior margin of the sulcus tympanicus, and 5.49 mm on images that show the bottom of the external acoustic meatus. The VFN is approximately 4.20 mm lateral to the promontorium tympani on images with the best view of the window niche and 4.12 mm lateral to the root of the tympanic ring on images with the inferior margin of the sulcus tympanicus. The other results indicate that the area and depth of the surgical wound from the improved approach would be much smaller than that from the typical approach. The surgical approach to the horizontal segment of the facial nerve through the external acoustic meatus and the tympanic cavity could be improved by grinding off the external acoustic meatus to show the VFN. The VFN can be found by taking the promontorium tympani and tympanic ring as references. This improvement is of high potential to expand the visual field to the facial nerve, remarkably without significant injury to the patients compared with the typical approach through the mastoid process.

Internal carotid artery in the operative plane of endoscopic endonasal transsphenoidal surgery.

The objective of this study was to measure the related parameters of intercarotid artery (ICA) in the operative plane of endonasal transsphenoidal approach for hypophyseal surgeries. Nine parameters of the ICA were examined in the computed tomographic angiographic (CTA) scan of 101 patients. The shortest distance between the middle point of the nasal columella and the projective point of the ICA (D(3)) was 85.50 (5.79) mm. The shortest distance between the anterior wall of the sphenoid sinus and the projective point of the ICA (D(4)) was 16.93 (3.50) mm. The distance between the bilateral projective points of the ICA (D(5)) was 21.60 (3.45) mm. The shortest distance from the anterior wall of the sphenoid sinus to the line between the bilateral projective points of the ICA (D(6)) was 12.1 (3.91) mm. The shortest distance between the middle point of nasal columella and the anterior wall of the sphenoid sinus (D(7)) was 72.67 (5.99) mm. The width of the angle between the bilateral ICA projective point from the middle point of the nasal columella (A(1)) was 14.9 (2.32) degrees. The width of the angle between the bilateral ICA projective points from the anterior-most point of sphenoid sinus (A(2)) was 85.49 (18.12) degrees. Clinically, it is relatively safe to work within the distances and angles measured in this research, and these results may provide information for clinical surgery of pituitary tumor.