Vertical Segment Of Facial Nerve Research Articles

Excursus in Chorda-Facial Angle Variation in Cochlear Implant Surgery: Cadaveric Temporal Bone Study.

Facial recess approach through posterior tympanotomy is the most common & best appraoch for facilitating Cochlear Implant surgery through the round window. Sacrificing Chorda tympani nerve can be avoided by proper understanding of the anatomy of the Facial Recess & Chorda-Facial angles. Hence it is important to know the Chorda-Facial angle to prevent injury in Facial recess approach during Cochlear Implant surgery. Objective This study is done to know the Chorda-Facial angle variation with Round Window visibility during the Facial recess approach which is of relevance in Cochlear Implant surgery. Methods Thirty adult normal wet human cadaveric temporal bones were studied by performing by Posterior Tympanotomy & Facial Recess approach by using ZEISS microscope. Photographs were taken by digital camera of 26 megapixel, imported into computer, then Chorda-Facial angle were measured by Digimizer software & mean angle was calculated. Results The mean angle between the facial nerve & chorda tympani nerve was 20.232°. Bifurcation of chorda tympani nerve at the level of origin itself from the vertical segment of facial nerve was found in 6 Temporal bones out of 30. Round window visibility was noted in all 30 temporal bone specimens (100%). Conclusion The wide Chorda-Facial angle variations, especially the narrowest angle should be known to the otologist in particular to the Cochlear Implant surgeon, which may help avoid inadvertent damage to the CTN in facial recess approach during Cochlear Implant surgery & use diamond burr size of 0.6mm or 0.8mm.

Invasion Patterns of External Auditory Canal Squamous Cell Carcinoma: A Histopathology Study.

To describe the histopathology of the invasion patterns of advanced-stage external auditory canal (EAC) squamous cell carcinoma (SCC). Study Design Retrospective cohort study. Retrospective analysis of medical records of patients diagnosed with EAC SCC available at the Massachusetts Eye and Ear temporal bone (TB) collection. TBs underwent processing for histologic examination. Hematoxylin and eosin-stained slides were examined. Histologic findings were compared to premortem clinical data. Nine TBs were identified. Male:female ratio was 6:3. The average age of diagnosis and duration of survival was 64 (46-80 years) and 2.3 years (1-50 months), respectively. All presented with T4 disease, most commonly due to petrous apex (PA) invasion and facial nerve (FN) weakness. The mastoid air cells system served as a tumor conduit to the tegmen mastoideum and overlying dura in four patients, posterior fossa dura in one patient, vertical segment of FN in four patients, and middle ear (ME) and lateral semicircular canal in five patients. The tumor did not penetrate the tympanic membrane, oval window membrane (fenestra vestibule), or round window (RW) membrane. Supra- and infralabyrinthine pneumatization patterns allowed direct routes to the PA. Translabyrinthine PA invasion was seen in two patients. The most common locus of otic capsule invasion was the cochlea. One patient had FN paralysis due to compression rather than invasion. SCC does not tend to extend from the ME to the inner ear through the RW and vestibule-stapedial ligament. Tumors tend to spread along the preexisting TB air-tract routes. Well-aerated TB, may facilitate extension to the PA. 4 Laryngoscope, 131:E590-E597, 2021.

Measurement and Analysis of Facial Nerve on Fully Displayed Multislice Computed Tomographic Multiplanar Reconstruction Image

The objectives of this study were to measure the length of horizontal segment of facial nerve (HFN), the length of vertical segment of facial nerve (VFN), and the angle between these 2 segments on a fully displayed multislice computed tomographic multiplanar reconstruction (MPR) images of HFN and VFN and to analyze the data with respects to side, sex, and age. Parameters of 234 patients (468 observations, 118 men and 116 women, aged 4-70 years) with intact temporal bone were measured on multislice computed tomographic multiplanar reconstruction images. The data gained were analyzed by statistical method. The left and right lengths of VFN were significantly different (P < 0.05). And the length of HFN, the length of VFN, and the angle between males and females were significantly different (P < 0.05). We divided the data into 3 groups to study correlations between measurements and age. In underaged group, there was a strong positive correlation between the length of VFN and age; the value of Pearson correlation was 0.645. And there was a weak correlation between the angle and the age; the value of Pearson correlation was 0.270. In older-aged group, there was a moderate negative correlation between the length of VFN and age; the value of Pearson correlation was -0.408. Our results are of high potential to expand the visual field to facial nerve and may provide more detailed information to surgeries of facial nerve, middle ear, and temporal bone.

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.